WorldWideScience

Sample records for atmospheric temperature

  1. Lidar observations of middle atmosphere temperature variability

    Directory of Open Access Journals (Sweden)

    G. P. Gobbi

    Full Text Available We discuss 223 middle atmosphere lidar temperature observations. The record was collected at Frascati (42°N–13°E, during the 41-month period January 1989-May 1992, corresponding to the maximum of solar cycle 22. The choice of this interval was aimed at minimizing the temperature variability induced by the 11-year solar cycle. The average climatology over the 41-month period and comparison with a reference atmosphere (CIRA86 are presented. Monthly temperature variability over the full period, during opposite quasi-biennial oscillation phases and on a short-term scale (0.5–4 h, is analyzed. Results indicate the 50–55-km region as less affected by variability caused by the natural phenomena considered in the analysis. Due to this minimum in natural noise characterizing the atmospheric temperature just above the stratopause, observations of that region are well suited to the detection of possible temperature trends induced by industrial activities.

  2. Regularization for Atmospheric Temperature Retrieval Problems

    Science.gov (United States)

    Velez-Reyes, Miguel; Galarza-Galarza, Ruben

    1997-01-01

    Passive remote sensing of the atmosphere is used to determine the atmospheric state. A radiometer measures microwave emissions from earth's atmosphere and surface. The radiance measured by the radiometer is proportional to the brightness temperature. This brightness temperature can be used to estimate atmospheric parameters such as temperature and water vapor content. These quantities are of primary importance for different applications in meteorology, oceanography, and geophysical sciences. Depending on the range in the electromagnetic spectrum being measured by the radiometer and the atmospheric quantities to be estimated, the retrieval or inverse problem of determining atmospheric parameters from brightness temperature might be linear or nonlinear. In most applications, the retrieval problem requires the inversion of a Fredholm integral equation of the first kind making this an ill-posed problem. The numerical solution of the retrieval problem requires the transformation of the continuous problem into a discrete problem. The ill-posedness of the continuous problem translates into ill-conditioning or ill-posedness of the discrete problem. Regularization methods are used to convert the ill-posed problem into a well-posed one. In this paper, we present some results of our work in applying different regularization techniques to atmospheric temperature retrievals using brightness temperatures measured with the SSM/T-1 sensor. Simulation results are presented which show the potential of these techniques to improve temperature retrievals. In particular, no statistical assumptions are needed and the algorithms were capable of correctly estimating the temperature profile corner at the tropopause independent of the initial guess.

  3. Reconciling atmospheric temperatures in the early Archean

    DEFF Research Database (Denmark)

    Pope, Emily Catherine; Bird, Dennis K.; Rosing, Minik Thorleif;

    rock record. The goal of this study is to compile and reconcile Archean geologic and geochemical features that are in some way controlled by surface temperature and/or atmospheric composition, so that at the very least paleoclimate models can be checked by physical limits. Data used to this end include...... the oxygen isotope record of chemical sediments and ancient ocean crust, chemical equilibria amongst primary phases in banded iron formations (BIFs), sedimentary features indicative of temperate or glacial environments, and paleosol indicators of atmospheric CO2. Further, we explore the extent to which...... hydrogen isotopes contribute to the geologic record as a signal for glaciations, continental growth and atmospheric methane levels. Oceanic serpentinites and subduction-related volcanic and hydrothermal environments obtain their hydrogen isotope signature from seawater, and thus may be used to calculate...

  4. Temperature Swings in a Hot Jupiter's Atmosphere

    Science.gov (United States)

    Kohler, Susanna

    2016-04-01

    Weather variations in the atmosphere of a planet on a highly eccentric orbit are naturally expected to be extreme. Now, a study has directly measured the wild changes in the atmosphere of a highly eccentric hot Jupiter as it passes close to its host star.Diagram of the HD 80606 system. The inset images labeled AH show the temperature distribution of the planet at different stages as it swings around its star. [de Wit et al. 2016]Eccentric OpportunityFor a hot Jupiter a gas giant that orbits close to its host star the exoplanet HD 80606 b exhibits a fairly unusual path. Rather than having a circularized orbit, HD 80606 b travels on an extremely elliptic 111-day orbit, with an eccentricity of e ~ 0.93. Since the amount of flux HD 80606 b receives from its host varies by a factor of ~850 over the course of its orbit, it stands to reason that this planet must have extreme weather swings!Now a team of scientists led by Julien de Wit (Massachusetts Institute of Technology) has reanalyzed old observations of HD 80606 and obtained new ones using the Spitzer Space Telescope. The longer observing time and new data analysis techniques allowed the team to gain new insights into how the exoplanets atmosphere responds to changes in the stellar flux it receives during its orbit.Extreme VariationsBy measuring the infrared light coming from HD 80606, de Wit and collaborators modeled the planets temperature during 80 hours of its closest approach to its host star. This period of time included the ~20 hours in which most of the planets temperature change is expected to occur, as it approaches to a distance a mere 6 stellar radii from its host.The authors find that the layer of the atmosphere probed by Spitzer heats rapidly from 500K to 1400K (thats ~440F to a scalding 2000+F!) as the planet approaches periastron.The atmosphere then cools similarly quickly as the planet heads away from the star once more.Relative infrared brightness of HD 80606 b at 4.5 and 8 m. The dip marks where

  5. Distributed Temperature Sensing in the Atmosphere

    Science.gov (United States)

    van de Giesen, Nicolaas; Selker, John; Sayde, Chadi; Thomas, Christoph K.; Higgins, Chad; Schilperoort, Bart; Coenders-Gerrits, Miriam; Luxemburg, Wim; Hilgersom, Koen; van Emmerik, Tim; Solcerova, Anna; Berghuijs, Wouter

    2016-04-01

    Over the past ten years, Distributed Temperature Sensing (DTS) has been applied for monitoring many different environmental processes, from groundwater movement, to seepage into streams and canals, to soil moisture, and internal waves in lakes. DTS uses optical fibres, along which temperatures are determined by measuring Raman shifts in light that scatters back after a laser pulse has been sent into the fiber. Over the past decade, performance of DTS equipment has dramatically improved. It is now possible to determine fiber temperatures with 0.05 K accuracy, for each 25 cm along a fiber optic cable. With typical spatial resolutions of 1 m, cable lengths can run up to 5 km. Accuracy improves with integration over longer sampling intervals, but measurements over 60 s can give 0.1 K accuracy with proper in-field calibration. DTS can also be used for atmospheric properties such as air temperature, vapor pressure, and wind speed. This presentation provides a complete overview of recent advances in atmospheric DTS observations. Air temperature is the simplest, as one simply has to suspend a fiber optic cable along the profile of interest. This can be from a balloon or along poles. Care has to be taken to correct for radiative heating of the cable. Using a thin white cable minimalizes radiative effects and normally brings the measured temperature to within 1 K of actual air temperature, sufficient for studies on effects of shading in natural and urban landscapes. It is also possible to correct for radiative heating by modeling in some detail the cable's thermal behavior or by using two cables of different diameters. Supporting structures may also have an effect on cable temperatures, which should be minimized or corrected for. Water vapor can be measured by comparing the temperatures of wet and dry cables. These wet and dry bulb temperatures allow derivation of humidity profiles, which, in turn, allows for Bowen-ratio type of calculations of latent and sensible heat

  6. Reconciling atmospheric temperatures in the early Archean

    Science.gov (United States)

    Pope, E. C.; Rosing, M.; Bird, D. K.; Albarede, F.

    2012-12-01

    Average surface temperatures of Earth in the Archean remain unresolved despite decades of diverse approaches to the problem. As in the present, early Earth climates were complex systems dependent on many variables. With few constraints on such variables, climate models must be relatively simplistic, and consider only one or two factors that drive Archean climate (e.g. a fainter young sun, a low albedo, the extent and effect of cloud cover, or the presence and abundance of a wide array of greenhouse and icehouse gasses). Compounded on the limitations of modeling is the sparse and often ambiguous Archean rock record. The goal of this study is to compile and reconcile Archean geologic and geochemical features that are in some way controlled by surface temperature and/or atmospheric composition, so that at the very least paleoclimate models can be checked by physical limits. Data used to this end include the oxygen isotope record of chemical sediments and ancient ocean crust, chemical equilibria amongst primary phases in banded iron formations (BIFs), sedimentary features indicative of temperate or glacial environments, and paleosol indicators of atmospheric CO2. Further, we explore the extent to which hydrogen isotopes contribute to the geologic record as a signal for glaciations, continental growth and atmospheric methane levels. Oceanic serpentinites and subduction-related volcanic and hydrothermal environments obtain their hydrogen isotope signature from seawater, and thus may be used to calculate secular variation in δDSEAWATER which may fluctuate significantly due to hydrogen escape, continental growth and large-scale glaciation events. Further, ancient records of low-δD meteoric fluids signal both cooler temperatures and the emergence of large continents (increasing the effects of continental weathering on climate). Selective alteration of δD in Isua rocks to values of -130 to -100‰ post-dates ca. 3.55Ga Ameralik dikes, but may be associated with a poorly

  7. Temperature structure in the atmospheric boundary layer

    Science.gov (United States)

    Smedman, Ann-Sofi

    2010-05-01

    Temperature structure in the atmospheric boundary layer It is well established from experimental and theoretical studies that the temperature structure in the atmospheric boundary layer is depends on stability. During free convection conditions the flow is dominated by circular thermals but when stratification is becoming slightly unstable longitudinal roll structures that extend vertically throughout the entire boundary layer will be present. In close to neutral conditions on the unstable side (the UVCN regime) when the Obukhov length is much greater than the surface layer depth, it is observed that the structure of the surface layer turbulence does not accord with standard similarity theory. In particular the efficiency of the turbulent exchange of sensible and latent heat is observed to be more strongly enhanced than is consistent with the standard model. Also the profiles of dissipation of turbulent kinetic energy and temperature fluctuation variance are found to depend on the structure of the whole boundary layer (i.e. are non-local), indicating that a large-scale transport process is at work. At the same time, co-spectral analysis shows how the large scale eddy motions that determine the heat transport process near the surface are typically 1/5 of the surface layer depth. All these features are found to be similar in measurements at two marine sites, in the Baltic Sea and in Lake Ontario respectively and at several flat land sites ( around Uppsala and at the Island of Gotland), indicating that they are determined by the dynamics of the whole boundary layer rather than being simply dependent on the surface boundary conditions. The observed structures can also be interpreted as possible manifestations of a bifurcation of the large scale eddy structure towards a state in which there are quasi-steady longitudinal rolls and, on a smaller scale, unsteady detached eddies. Our interpretation of the results from the measurements is that, in the UVCN regime, the latter

  8. TES/Aura L2 Atmospheric Temperatures Limb V005

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  9. TES/Aura L2 Atmospheric Temperatures Limb V004

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  10. TES/Aura L2 Atmospheric Temperatures Nadir V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  11. TES/Aura L2 Atmospheric Temperatures Nadir V006

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  12. TES/Aura L2 Atmospheric Temperatures Nadir V004

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  13. TES/Aura L2 Atmospheric Temperatures Limb V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  14. TES/Aura L2 Atmospheric Temperatures Limb V006

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  15. TES/Aura L2 Atmospheric Temperatures Nadir V005

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  16. Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature Differences

    CERN Document Server

    Komacek, Thaddeus D

    2016-01-01

    The full-phase infrared light curves of low-eccentricity hot Jupiters show a trend of increasing dayside-to-nightside brightness temperature difference with increasing equilibrium temperature. Here we present a three-dimensional model that explains this relationship, in order to shed insight on the processes that control heat redistribution in tidally-locked planetary atmospheres. This three-dimensional model combines predictive analytic theory for the atmospheric circulation and dayside-nightside temperature differences over a range of equilibrium temperature, atmospheric composition, and potential frictional drag strengths with numerical solutions of the circulation that verify this analytic theory. This analytic theory shows that the longitudinal propagation of waves mediates dayside-nightside temperature differences in hot Jupiter atmospheres, analogous to the wave adjustment mechanism that regulates the thermal structure in Earth's tropics. These waves can be damped in hot Jupiter atmospheres by either r...

  17. LIDAR for atmospheric backscatter and temperature measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objectives of this effort are to measure atmospheric backscatter profiles and temperature using a zenith looking lidar, designed for a small lander.The lidar...

  18. Fast Temperature Sensor for use in Atmospheric Sciences Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Southwest Sciences proposes a novel sensor to measure atmospheric temperature at high frequency (10 Hz) and with high precision and accuracy (0.1 degrees C)....

  19. ATMOSPHERIC CIRCULATION OF HOT JUPITERS: DAYSIDE–NIGHTSIDE TEMPERATURE DIFFERENCES

    Energy Technology Data Exchange (ETDEWEB)

    Komacek, Thaddeus D.; Showman, Adam P., E-mail: tkomacek@lpl.arizona.edu [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721 (United States)

    2016-04-10

    The full-phase infrared light curves of low-eccentricity hot Jupiters show a trend of increasing dayside-to-nightside brightness temperature difference with increasing equilibrium temperature. Here, we present a three-dimensional model that explains this relationship, in order to provide insight into the processes that control heat redistribution in tidally locked planetary atmospheres. This three-dimensional model combines predictive analytic theory for the atmospheric circulation and dayside–nightside temperature differences over a range of equilibrium temperatures, atmospheric compositions, and potential frictional drag strengths with numerical solutions of the circulation that verify this analytic theory. The theory shows that the longitudinal propagation of waves mediates dayside–nightside temperature differences in hot Jupiter atmospheres, analogous to the wave adjustment mechanism that regulates the thermal structure in Earth’s tropics. These waves can be damped in hot Jupiter atmospheres by either radiative cooling or potential frictional drag. This frictional drag would likely be caused by Lorentz forces in a partially ionized atmosphere threaded by a background magnetic field, and would increase in strength with increasing temperature. Additionally, the amplitude of radiative heating and cooling increases with increasing temperature, and hence both radiative heating/cooling and frictional drag damp waves more efficiently with increasing equilibrium temperature. Radiative heating and cooling play the largest role in controlling dayside–nightside temperature differences in both our analytic theory and numerical simulations, with frictional drag only being important if it is stronger than the Coriolis force. As a result, dayside–nightside temperature differences in hot Jupiter atmospheres increase with increasing stellar irradiation and decrease with increasing pressure.

  20. Improved controlled atmosphere high temperature scanning probe microscope

    OpenAIRE

    Hansen, Karin Vels; Wu, Yuehua; Jacobsen, Torben; Mogensen, Mogens Bjerg; Kuhn, Luise Theil

    2013-01-01

    To locally access electrochemical active surfaces and interfaces in operando at the sub-micron scale at high temperatures in a reactive gas atmosphere is of great importance to understand the basic mechanisms in new functional materials, for instance, for energy technologies, such as solid oxide fuel cells and electrolyzer cells. Here, we report on advanced improvements of our original controlled atmosphere high temperature scanning probe microscope, CAHT-SPM. The new microscope can employ a ...

  1. Temperature field simulation of gob influenced by atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    王刚; 罗海珠; 梁运涛; 王继仁

    2015-01-01

    The current temperature field model of mine gob does not take the boundary conditions of the atmospheric pressure into account, while the actual atmospheric pressure is influenced by weather, so as to produce differences between ventilation negative pressure of the working face and the negative pressure of gas drainage in gob, thus interfering the calculated results of gob temperature field. According to the characteristics of the actual air flow and temperature change in gob, a two-dimensional temperature field model of the gob was built, and the relational model between the air pressure of intake and outlet of the gob and the atmospheric pressure was established, which was introduced into the boundary conditions of temperature field to conduct calculation. By means of analysis on the simulation example, and comparison with the traditional model, the results indicate that atmospheric pressure change had notable impact on the distribution of gob temperature field. The laboratory test system of gob temperature field was constructed, and the relative error between simulated and measured value was no greater than 9.6%, which verified the effectiveness of the proposed model. This work offers theoretical basis for accurate calculation of temperature and prediction of ignition source in mine gob, and has important implications on preventing spontaneous combustion of coal.

  2. Simulation of atmospheric temperature effects on cosmic ray muon flux

    Energy Technology Data Exchange (ETDEWEB)

    Tognini, Stefano Castro; Gomes, Ricardo Avelino [Instituto de Física, Universidade Federal de Goiás, CP 131, 74001-970, Goiânia, GO (Brazil)

    2015-05-15

    The collision between a cosmic ray and an atmosphere nucleus produces a set of secondary particles, which will decay or interact with other atmosphere elements. This set of events produced a primary particle is known as an extensive air shower (EAS) and is composed by a muonic, a hadronic and an electromagnetic component. The muonic flux, produced mainly by pions and kaons decays, has a dependency with the atmosphere’s effective temperature: an increase in the effective temperature results in a lower density profile, which decreases the probability of pions and kaons to interact with the atmosphere and, consequently, resulting in a major number of meson decays. Such correlation between the muon flux and the atmosphere’s effective temperature was measured by a set of experiments, such as AMANDA, Borexino, MACRO and MINOS. This phenomena can be investigated by simulating the final muon flux produced by two different parameterizations of the isothermal atmospheric model in CORSIKA, where each parameterization is described by a depth function which can be related to the muon flux in the same way that the muon flux is related to the temperature. This research checks the agreement among different high energy hadronic interactions models and the physical expected behavior of the atmosphere temperature effect by analyzing a set of variables, such as the height of the primary interaction and the difference in the muon flux.

  3. Ocean versus atmosphere control on western European wintertime temperature variability

    Science.gov (United States)

    Yamamoto, Ayako; Palter, Jaime B.; Lozier, M. Susan; Bourqui, Michel S.; Leadbetter, Susan J.

    2015-12-01

    Using a novel Lagrangian approach, we assess the relative roles of the atmosphere and ocean in setting interannual variability in western European wintertime temperatures. We compute sensible and latent heat fluxes along atmospheric particle trajectories backtracked in time from four western European cities, using a Lagrangian atmospheric dispersion model driven with meteorological reanalysis data. The material time rate of change in potential temperature and the surface turbulent fluxes computed along the trajectory show a high degree of correlation, revealing a dominant control of ocean-atmosphere heat and moisture exchange in setting heat flux variability for atmospheric particles en route to western Europe. We conduct six idealised simulations in which one or more aspects of the climate system is held constant at climatological values and these idealised simulations are compared with a control simulation, in which all components of the climate system vary realistically. The results from these idealised simulations suggest that knowledge of atmospheric pathways is essential for reconstructing the interannual variability in heat flux and western European wintertime temperature, and that variability in these trajectories alone is sufficient to explain at least half of the internannual flux variability. Our idealised simulations also expose an important role for sea surface temperature in setting decadal scale variability of air-sea heat fluxes along the Lagrangian pathways. These results are consistent with previous studies showing that air-sea heat flux variability is driven by the atmosphere on interannual time scales over much of the North Atlantic, whereas the SST plays a leading role on longer time scales. Of particular interest is that the atmospheric control holds for the integrated fluxes along 10-day back trajectories from western Europe on an interannual time scale, despite that many of these trajectories pass over the Gulf Stream and its North Atlantic

  4. Assessing atmospheric temperature data sets for climate studies

    Directory of Open Access Journals (Sweden)

    Magnus Cederlöf

    2016-07-01

    Full Text Available Observed near-surface temperature trends during the period 1979–2014 show large differences between land and ocean, with positive values over land (0.25–0.27 °C/decade that are significantly larger than over the ocean (0.06–0.12 °C/decade. Temperature trends in the mid-troposphere of 0.08-0.11 °C/decade, on the other hand, are similar for both land and ocean and agree closely with the ocean surface temperature trend. The lapse rate is consequently systematically larger over land than over the ocean and also shows a positive trend in most land areas. This is puzzling as a response to external warming, such as from increasing greenhouse gases, is broadly the same throughout the troposphere. The reduced tropospheric warming trend over land suggests a weaker vertical temperature coupling indicating that some of the processes in the planetary boundary layer such as inversions have a limited influence on the temperature of the free atmosphere. Alternatively, the temperature of the free atmosphere is influenced by advection of colder tropospheric air from the oceans. It is therefore suggested to use either the more robust tropospheric temperature or ocean surface temperature in studies of climate sensitivity. We also conclude that the European Centre for Medium-Range Weather Forecasts Reanalysis Interim can be used to obtain consistent temperature trends through the depth of the atmosphere, as they are consistent both with near-surface temperature trends and atmospheric temperature trends obtained from microwave sounding sensors.

  5. Dayside-Nightside Temperature Differences in Hot Jupiter Atmospheres

    Science.gov (United States)

    Komacek, Thaddeus D.; Showman, Adam P.

    2015-12-01

    The infrared phase curves of low-eccentricity transiting hot Jupiters show a trend of increasing flux amplitude, or increasing day-night temperature difference, with increasing equilibrium temperature. Here we utilize atmospheric circulation modeling and analytic theory to understand this trend, and the more general question: what processes control heat redistribution in tidally-locked giant planet atmospheres? We performed a wide range of 3D numerical simulations of the atmospheric circulation with simplified forcing, and constructed an analytic theory that explains the day-night temperature differences in these simulations over a wide parameter space. Our analytic theory shows that day-night temperature differences in tidally-locked planet atmospheres are mediated by wave propagation. If planetary-scale waves are free to propagate longitudinally, they will efficiently flatten isentropes and lessen day-night temperature differences. If these waves are damped, the day-night temperature differences will necessarily be larger. We expect that wave propagation in hot Jupiter atmospheres can be damped in two ways: by either radiative cooling or frictional drag. Both of these processes increase in efficacy with increasing equilibrium temperature, as radiative cooling is directly related to the cube of temperature and magnetically-induced (Lorentz) drag becomes stronger with increasing partial ionization and hence temperature. We find that radiative cooling plays the largest role in damping wave propagation and hence plays the biggest role in controlling day-night temperature differences. As a result, day-night temperature differences in hot Jupiter atmospheres decrease with increasing pressure and increase with increasing stellar flux. One can apply this result to phase curve observations of individual hot Jupiters in multiple bandpasses, as varying flux amplitudes between wavelengths implies that different photospheric pressure levels are being probed. Namely, a larger

  6. Atmospheric temperature sensing with a multiorder Fabry-Perot interferometer.

    Science.gov (United States)

    Wang, J; Drayson, S R; Hayes, P B

    1989-12-01

    A Fabry-Perot interferometer has a periodic response. By matching the free spectral range of a Fabry-Perot interferometer (FPI) with the period of the CO(2) spectrum, considerable advantages of throughput and spectral resolution can be achieved, leading to high spectral resolution and vertical resolution for atmospheric temperature sounders. In this paper, the concept of a high resolution multiorder Fabry-Perot interferometer using portions of the 15-microm and 4.3-microm bands of CO(2)for the purpose of atmospheric temperature sounding is discussed. Suitable sounding spectral positions, FPI free spectral range, and weighting functions are calculated. An effective spectral resolution of 0.02 cm(-1) can be achieved by the proposed sounder with a FPI finess of ~100 which is within the present state-of-the-art technology in the infrared region, leading to considerable improvement in the vertical resolution of the atmospheric temperature sounder. PMID:20555996

  7. Dayside-Nightside Temperature Differences in Hot Jupiter Atmospheres

    Science.gov (United States)

    Komacek, T. D.; Showman, A. P.

    2015-12-01

    The full-phase light curves of individual close-in extrasolar giant planets, or "hot Jupiters," show a trend of increasing fractional amplitude with increasing planetary equilibrium temperature. The attached figure shows this trend for 7 transiting low-eccentricity hot Jupiters. For these planets, this trend can be realized as a trend of increasing dayside-to-nightside temperature difference with increasing equilibrium temperature, as these planets are expected to be tidally locked. Here we examine this trend, in order to shed insight on the physical processes that regulate heat redistribution in tidally-locked planet atmospheres. We utilize a combination of analytic theory to predict how heat is redistributed from day to night over a range of equilibrium temperature, atmospheric composition, and potential frictional drag strengths, and confirm the theory using numerical circulation modeling. Our theory identifies that the transition from low to high day-night temperature differences is mediated by wave adjustment, the same process that regulates heat redistribution in the tropics of Earth. Due to their low rotation rate and hence large Rossby deformation radius, tidally locked planets allow for wave propagation to occur over a much larger latitude range than on Earth. Hence, wave adjustment processes play a key role in the the global, not just equatorial, heat redistribution in hot Jupiter atmospheres. Wave propagation can be damped in hot Jupiter atmospheres by either radiative cooling to space or potential frictional drag. This frictional drag, if present, would likely be caused by Lorentz forces in a partially ionized atmosphere threaded by a planetary-scale magnetic field. The radiative cooling timescale is inversely related to the cube of temperature, and any Lorentz drag would increase with temperature due to the increasing ionization fraction of the atmosphere. Hence, both of these processes damp waves more effectively as equilibrium temperature increases

  8. Atmospheric CO2: principal control knob governing Earth's temperature.

    Science.gov (United States)

    Lacis, Andrew A; Schmidt, Gavin A; Rind, David; Ruedy, Reto A

    2010-10-15

    Ample physical evidence shows that carbon dioxide (CO(2)) is the single most important climate-relevant greenhouse gas in Earth's atmosphere. This is because CO(2), like ozone, N(2)O, CH(4), and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapor can and does. Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect. Without the radiative forcing supplied by CO(2) and the other noncondensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state. PMID:20947761

  9. Improved controlled atmosphere high temperature scanning probe microscope

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Wu, Yuehua; Jacobsen, Torben;

    2013-01-01

    fuel cells and electrolyzer cells. Here, we report on advanced improvements of our original controlled atmosphere high temperature scanning probe microscope, CAHT-SPM. The new microscope can employ a broad range of the scanning probe techniques including tapping mode, scanning tunneling microscopy...

  10. High temperature condensate clouds in super-hot Jupiter atmospheres

    CERN Document Server

    Wakeford, Hannah R; Lewis, Nikole K; Kataria, Tiffany; Marley, Mark S; Fortney, Jonathan J; Mandell, Avi M

    2016-01-01

    Deciphering the role of clouds is central to our understanding of exoplanet atmospheres, as they have a direct impact on the temperature and pressure structure, and observational properties of the planet. Super-hot Jupiters occupy a temperature regime similar to low mass M-dwarfs, where minimal cloud condensation is expected. However, observations of exoplanets such as WASP-12b (Teq ~ 2500 K) result in a transmission spectrum indicative of a cloudy atmosphere. We re-examine the temperature and pressure space occupied by these super-hot Jupiter atmospheres, to explore the role of the initial Al- and Ti-bearing condensates as the main source of cloud material. Due to the high temperatures a majority of the more common refractory material is not depleted into deeper layers and would remain in the vapor phase. The lack of depletion into deeper layers means that these materials with relatively low cloud masses can become significant absorbers in the upper atmosphere. We provide condensation curves for the initial ...

  11. Phase relation between global temperature and atmospheric carbon dioxide

    OpenAIRE

    Stallinga, Peter; Khmelinskii, Igor

    2013-01-01

    The primary ingredient of Anthropogenic Global Warming hypothesis is the assumption that atmospheric carbon dioxide variations are the cause for temperature variations. In this paper we discuss this assumption and analyze it on basis of bi-centenary measurements and using a relaxation model which causes phase shifts and delays.

  12. Temperature diagnostics of the solar atmosphere using SunPy

    CERN Document Server

    Leonard, Andrew

    2014-01-01

    The solar atmosphere is a hot (about 1MK), magnetised plasma of great interest to physicists. There have been many previous studies of the temperature of the Sun's atmosphere (Plowman2012, Wit2012, Hannah2012, Aschwanden2013, etc.). Almost all of these studies use the SolarSoft software package written in the commercial Interactive Data Language (IDL), which has been the standard language for solar physics. The SunPy project aims to provide an open-source library for solar physics. This work presents (to the authors' knowledge) the first study of its type to use SunPy rather than SolarSoft. This work uses SunPy to process multi-wavelength solar observations made by the Atmospheric Imaging Assembly (AIA) instrument aboard the Solar Dynamics Observatory (SDO) and produce temperature maps of the Sun's atmosphere. The method uses SunPy's utilities for querying databases of solar events, downloading solar image data, storing and processing images as spatially aware Map objects, and tracking solar features as the S...

  13. Simulation of low temperature atmospheric pressure corona discharge in helium

    Science.gov (United States)

    Bekasov, Vladimir; Kirsanov, Gennady; Eliseev, Stepan; Kudryavtsev, Anatoly; Sisoev, Sergey

    2015-11-01

    The main objective of this work was to construct a numerical model of corona discharge in helium at atmospheric pressure. The calculation was based on the two-dimensional hybrid model. Two different plasma-chemical models were considered. Models were built for RF corona and negative DC corona discharge. The system of equations is solved by the finite element method in the COMSOL Multiphysics. Main parameters of the discharge (the density of charged and excited particles, the electron temperature) and their dependence on the input parameters of the model (geometry, electrode voltage, power) were calculated. The calculations showed that the shape of the electron distribution near the electrode depends on the discharge power. The neutral gas heating data obtained will allow predicting the temperature of the gases at the designing of atmospheric pressure helium plasma sources.

  14. Low Temperature and Modified Atmosphere: Hurdles for Antibiotic Resistance Transfer?

    Science.gov (United States)

    Van Meervenne, Eva; Van Coillie, Els; Van Weyenberg, Stephanie; Boon, Nico; Herman, Lieve; Devlieghere, Frank

    2015-12-01

    Food is an important dissemination route for antibiotic-resistant bacteria. Factors used during food production and preservation may contribute to the transfer of antibiotic resistance genes, but research on this subject is scarce. In this study, the effect of temperature (7 to 37°C) and modified atmosphere packaging (air, 50% CO2-50% N2, and 100% N2) on antibiotic resistance transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes was evaluated. Filter mating was performed on nonselective agar plates with high-density inocula. A more realistic setup was created by performing modified atmosphere experiments on cooked ham using high-density and low-density inocula. Plasmid transfer was observed between 10 and 37°C, with plasmid transfer also observed at 7°C during a prolonged incubation period. When high-density inocula were used, transconjugants were detected, both on agar plates and cooked ham, under the three atmospheres (air, 50% CO2-50% N2, and 100% N2) at 7°C. This yielded a median transfer ratio (number of transconjugants/number of recipients) with an order of magnitude of 10(-4) to 10(-6). With low-density inocula, transfer was only detected under the 100% N2 atmosphere after 10-day incubation at 7°C, yielding a transfer ratio of 10(-5). Under this condition, the highest bacterial density was obtained. The results indicate that low temperature and modified atmosphere packaging, two important hurdles in the food industry, do not necessarily prevent plasmid transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes.

  15. The atmospheric temperatures over Olympus Mons on Mars: An atmospheric hot ring

    Science.gov (United States)

    Wolkenberg, P.; Formisano, V.; Rinaldi, G.; Geminale, A.

    2010-05-01

    We study the thermal fields over Olympus Mons separating seasons (northern spring and summer against southern spring and summer) and local time observations (day side versus night side). Temperature vertical profiles retrieved from Planetary Fourier Spectrometer on board Mars Express (PFS-MEX) data have been used. In many orbits (running north to south along a meridian) passing over the top of the volcano there is evidence of a hot air on top of the volcano, of two enhancement of the air temperature both north and south of it and in between a collar of air that is colder than nearby at low altitudes, and warmer than nearby at high altitudes. Mapping together many orbits passing over or near the volcano we find that the hot air has the tendency to form an hot ring around it. This hot structure occurs mostly between LT = 10.00 and 15.00 and during the northern summer. Distance of the hot structure from the top of the volcano is about 600 km (10° of latitude). The hot atmospheric region is 300-420 km (5-7°) wide. Hot ring temperature contrasts of about 40 K occur at 2 km above the surface and decrease to 20 K at 5 km and to 10 K at 10 km. The atmospheric circulation over an area of 40° × 40° (latitudes and longitudes) is affected by the topography and the presence of Olympus Mons (-133°W, 18°N). We discuss also the thermal stability of the atmosphere over the selected area using the potential temperatures. The temperature field over the top of the volcano shows unstable atmosphere within 10 km from the surface. Finally, we interpret the hot temperatures around volcano as an adiabatic compression of down-welling branch coming from over the top of volcano. Different air temperature profiles are observed in the same seasons during the night, or in different seasons. In northern spring-summer during the night the isothermal contours do not show the presence of the volcano until we reach close to the surface very much, where a thermal inversion is observed. The

  16. NOAA Climate Data Record (CDR) of Upper Atmospheric Temperature 4 Layer Microwave, Version 3.3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 4 Layer Upper Atmosphere Temperature (UAT) Climate Data Record (CDR) dataset is a monthly analysis of the tropospheric and stratospheric data using temperature...

  17. Atmospheric Temperature Profile Measurements Using Mobile High Spectral Resolution Lidar

    Science.gov (United States)

    Razenkov, Ilya I.; Eloranta, Edwin W.

    2016-06-01

    The High Spectral Resolution Lidar (HSRL) designed at the University of Wisconsin-Madison discriminates between Mie and Rayleigh backscattering [1]. It exploits the Doppler effect caused by thermal motion of molecules, which broadens the spectrum of the transmitted laser light. That allows for absolute calibration of the lidar and measurements of the aerosol volume backscatter coefficient. Two iodine absorption filters with different absorption line widths (a regular iodine vapor filter and Argon buffered iodine filter) allow for atmospheric temperature profile measurements. The sensitivity of the measured signal-to-air temperature ratio is around 0.14%/K. The instrument uses a shared telescope transmitter-receiver design and operates in eyesafe mode (the product of laser average power and telescope aperture equals 0.1 Wm2 at 532 nm).

  18. Atmospheric Temperature Profile Measurements Using Mobile High Spectral Resolution Lidar

    Directory of Open Access Journals (Sweden)

    Razenkov Ilya I.

    2016-01-01

    Full Text Available The High Spectral Resolution Lidar (HSRL designed at the University of Wisconsin-Madison discriminates between Mie and Rayleigh backscattering [1]. It exploits the Doppler effect caused by thermal motion of molecules, which broadens the spectrum of the transmitted laser light. That allows for absolute calibration of the lidar and measurements of the aerosol volume backscatter coefficient. Two iodine absorption filters with different absorption line widths (a regular iodine vapor filter and Argon buffered iodine filter allow for atmospheric temperature profile measurements. The sensitivity of the measured signal-to-air temperature ratio is around 0.14%/K. The instrument uses a shared telescope transmitter-receiver design and operates in eyesafe mode (the product of laser average power and telescope aperture equals 0.1 Wm2 at 532 nm.

  19. Temperature retrieval at the southern pole of the Venusian atmosphere

    Science.gov (United States)

    Garate-Lopez, Itziar; Garcia-Munoz, A.; Hueso, R.; Sanchez-Lavega, A.

    2013-10-01

    Venus’ thermal radiation spectrum is punctuated by CO2 bands of various strengths probing into different atmospheric depths. It is thus possible to invert measured spectra of thermal radiation to infer atmospheric temperature profiles. VIRTIS-M observations of Venus in the 3-5 µm range allow us to study the night time thermal structure of the planet’s upper troposphere and lower mesosphere from 50 to 105 km [1, 2]. Building a forward radiative transfer model that solves the radiative transfer equation for the atmosphere on a line-by-line basis, we confirmed that aerosol scattering must be taken into account and we studied the impact of factors such as cloud opacity, and the size, composition and vertical distribution of aerosols [3]. The cloud top altitude and aerosol scale height have a notable impact on the spectrum. However, their weighting function matrices have similar structures contributing to the degeneracy of the temperature retrieval algorithm [2]. Our retrieval code is focused on the strong 4.3µm CO2 band, which enables the determination of the thermal profile above the cloud top, and based on the algorithm proposed by Grassi et al. (2008) in their equation (2). We present temperature maps for the south pole of Venus, where a highly variable vortex is observed. We aim to combine these maps with our previously measured velocity fields from the same VIRTIS-M infrared images [4], in order to infer the potential vorticity distribution for different vortex configurations and to improve the understanding of its unpredictable character and its role in the general atmospheric circulation. Acknowledgements This work was supported by the Spanish MICIIN projects AYA2009-10701 and AYA2012-36666 with FEDER funds, by Grupos Gobierno Vasco IT-765-13 and by Universidad País Vasco UPV/EHU through program UFI11/55. IGL and AGM gratefully acknowledge ESA/RSSD for hospitality and access to ‘The Grid’ computing resources. References [1] Roos-Serote, M., et al

  20. Diurnal Variation of Air Temperature in the Atmospheric Surface Layer

    Directory of Open Access Journals (Sweden)

    Tanja Likso

    2006-09-01

    Full Text Available In order to illustrate the nature of the diurnal temperature variations in the atmospheric surface layer in all seasons a set of hourly observations at the Zagreb-Maksimir Observatory (Croatia, measured at three different levels (5 cm, 50 cm and 2 m above ground during the year 2005, was used. An approximate method for calculating air temperature at 5 cm, using the air temperature at 2 m, is presented. For this purpose, hourly data (screen height temperature, cloudiness, air pressure at barometer level and wind speed at 2 m collected at the Zagreb-Maksimir Observatory during the summer season of 2005 have been used. Th is method is based on the Monin-Obukhov similarity theory. Estimated values have been compared with observations. The results obtained are the most accurate for cloudy weather, and the least accurate in the case of clear sky. A systematic error of this approach was discovered using a clustering procedure and is briefly discussed.

  1. Diurnal Variation of Air Temperature in the Atmospheric Surface Layer

    Directory of Open Access Journals (Sweden)

    Tanja Likso

    2006-12-01

    Full Text Available In order to illustrate the nature of the diurnal temperature variations in the atmospheric surface layer in all seasons a set of hourly observations at the Zagreb-Maksimir Observatory (Croatia, measured at three different levels (5 cm, 50 cm and 2 m above ground during the year 2005, was used. An approximate method for calculating air temperature at 5 cm, using the air temperature at 2 m, is presented. For this purpose, hourly data (screen height temperature, cloudiness, air pressure at barometer level and wind speed at 2 m collected at the Zagreb-Maksimir Observatory during the summer season of 2005 have been used. Th is method is based on the Monin-Obukhov similarity theory. Estimated values have been compared with observations. The results obtained are the most accurate for cloudy weather, and the least accurate in the case of clear sky. A systematic error of this approach was discovered using a clustering procedure and is briefly discussed.

  2. Application of an acoustic noise removal method to aircraft-based atmospheric temperature measurements

    Science.gov (United States)

    Hugo, Ronald J.; Nowlin, Scott R.; Hahn, Ila L.; Eaton, Frank D.; McCrae, Kim A.

    2003-01-01

    An acoustic noise removal method is used to reject engine acoustical disturbances from aircraft-based atmospheric temperature measurements. Removal of engine noise from atmospheric temperature measurements allows a larger wave number range to be fit while quantifying the magnitude of atmospheric temperature turbulence. The larger wave number range was found to result in a more statistically certain spectral slope estimate, with up to a 50% reduction in the standard deviation of measured spectral slopes. The noise removal technique was found to break down under conditions of weak atmospheric temperature turbulence where the engine acoustical disturbance can be several orders of magnitude larger than atmospheric temperature turbulence.

  3. Accuracy analysis on Rayleigh lidar measurements of atmospheric temperature based on spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Kun Liang; Yong Ma; Fei Cheng; Hongyuan Wang

    2009-01-01

    We make a detailed analysis on the linearity and accuracy of the relationship between the full-width at half-height (FWHH) of the atmosphere molecules Rayleigh scattering spectrum and the square root of the atmospheric temperature. A simulation of the FWHH of the atmosphere molecules Rayleigh scattering spectrum is made based on the S6 Atmosphere Model and U.S. Standard Atmosphere Model. The calcu-lated temperature is compared with the initial simulation temperature. The result shows that the FWHH of the atmosphere molecules Rayleigh scattering spectrum is nearly proportional to the atmospheric tem-perature. The goodness-of-fit index of the fitting curve is 0.9977 and the maximum absolute error of measured atmospheric temperature is about 2 K.

  4. TES/Aura L3 Atmospheric Temperatures Monthly Gridded V002

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  5. TES/Aura L3 Atmospheric Temperatures Monthly Gridded V001

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  6. TES/Aura L3 Atmospheric Temperatures Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  7. TES/Aura L3 Atmospheric Temperatures Daily Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Daily atmospheric temperature and VMR for the atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard pressure...

  8. TES/Aura L2 Atmospheric Temperatures Limb Special Observation V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  9. TES/Aura L2 Atmospheric Temperatures Nadir Special Observation V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  10. TES/Aura L2 Atmospheric Temperatures Nadir Special Observation V005

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  11. TES/Aura L2 Atmospheric Temperatures Limb Special Observation V004

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  12. TES/Aura L2 Atmospheric Temperatures Nadir Special Observation V004

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  13. TES/Aura L2 Atmospheric Temperatures Limb Special Observation V006

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  14. TES/Aura L2 Atmospheric Temperatures Limb Special Observation V005

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  15. TES/Aura L2 Atmospheric Temperatures Nadir Special Observation V006

    Data.gov (United States)

    National Aeronautics and Space Administration — Atmospheric vertical profile estimates and associated errors (diagonals and covariance matrices), along with retrieved surface temperature, cloud effective optical...

  16. Effect of O3 on the atmospheric temperature structure of early Mars

    CERN Document Server

    von Paris, P; Godolt, M; Grenfell, J L; Stracke, B; Rauer, H

    2015-01-01

    Ozone is an important radiative trace gas in the Earth's atmosphere. The presence of ozone can significantly influence the thermal structure of an atmosphere, and by this e.g. cloud formation. Photochemical studies suggest that ozone can form in carbon dioxide-rich atmospheres. We investigate the effect of ozone on the temperature structure of simulated early Martian atmospheres. With a 1D radiative-convective model, we calculate temperature-pressure profiles for a 1 bar carbon dioxide atmosphere. Ozone profiles are fixed, parameterized profiles. We vary the location of the ozone layer maximum and the concentration at this maximum. The maximum is placed at different pressure levels in the upper and middle atmosphere (1-10 mbar). Results suggest that the impact of ozone on surface temperatures is relatively small. However, the planetary albedo significantly decreases at large ozone concentrations. Throughout the middle and upper atmospheres, temperatures increase upon introducing ozone due to strong UV absorpt...

  17. VUV-absorption cross section of CO2 at high temperatures and impact on exoplanet atmospheres

    CERN Document Server

    Venot, Olivia; Bénilan, Yves; Gazeau, Marie-Claire; Hébrard, Eric; Larcher, Gwenaelle; Schwell, Martin; Dobrijevic, Michel; Selsis, Franck

    2015-01-01

    Ultraviolet (UV) absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar system. Transiting exoplanets whose atmospheres can now be studied by transit spectroscopy receive extremely strong UV fluxes and have typical temperatures ranging from 400 to 2500 K. At these temperatures, UV photolysis cross section data are severely lacking. Our goal is to provide high-temperature absorption cross sections and their temperature dependency for important atmospheric compounds. This study is dedicated to CO2, which is observed and photodissociated in exoplanet atmospheres. We performed these measurements for the 115 - 200 nm range at 300, 410, 480, and 550 K. In the 195 - 230 nm range, we worked at seven temperatures between 465 and 800 K. We found that the absorption cross section of CO2 is very sensitive to temperature, especially above 160 nm....

  18. VUV-absorption cross section of CO2 at high temperatures and impact on exoplanet atmospheres

    OpenAIRE

    Venot Olivia; Fray Nicolas; Bénilan Yves; Gazeau Marie-Claire; Hébrard Eric; Larcher Gwenaelle; Schwell Martin; Dobrijevic Michel; Selsis Franck

    2014-01-01

    Ultraviolet (UV) absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar system. Transiting exoplanets whose atmospheres can now be studied by transit spectroscopy receive extremely strong UV fluxes and have typical temperatures ranging from 400 to 2500 K. At these temperatures, UV photolysis cross section data are se...

  19. Convective cells of internal gravity waves in the earth's atmosphere with finite temperature gradient

    Directory of Open Access Journals (Sweden)

    O. Onishchenko

    2013-03-01

    Full Text Available In this paper, we have investigated vortex structures (e.g. convective cells of internal gravity waves (IGWs in the earth's atmosphere with a finite vertical temperature gradient. A closed system of nonlinear equations for these waves and the condition for existence of solitary convective cells are obtained. In the atmosphere layers where the temperature decreases with height, the presence of IGW convective cells is shown. The typical parameters of such structures in the earth's atmosphere are discussed.

  20. Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets

    OpenAIRE

    Kasting, James F.; Chen, Howard; Kopparapu, Ravi Kumar

    2015-01-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3-D calculations. However, at surface temperatures above 350 K, the stratosphere warms and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a '...

  1. The effect of atmospheric temperature and pressure on the occurrence of acute myocardial infarction in Kaunas.

    Science.gov (United States)

    Radišauskas, Ričardas; Vaičiulis, Vidmantas; Ustinavičienė, Rūta; Bernotienė, Gailutė

    2013-01-01

    OBJECTIVE. The aim of the study was to evaluate the impact of meteorological variables (atmospheric temperature and pressure) on the daily occurrence of acute myocardial infarction (AMI). MATERIAL AND METHODS. The study used the daily values of atmospheric temperature and pressure in 2000-2007. The meteorological data were obtained from the Lithuanian Hydrometeorological Service for Kaunas. The relative risks of event occurrence were computed for 5°C atmospheric temperature and for 10-hPa atmospheric pressure variations by means of the Poisson regression model. RESULTS. The occurrence of AMI and atmospheric temperature showed an inverse linear relationship, while the occurrence of AMI and atmospheric pressure, a positive linear relationship. Among the youngest subjects (25-44 years old), no relationships were detected. Contrary, among the subjects aged 45-64 years and those aged 65 years and older, the occurrence of AMI significantly decreased with higher temperature (P=0.001 and P=0.002, respectively). A decrease in atmospheric temperature by 10ºC reduced the risk of AMI by 8.7% in the age groups of 45-64 and 65 years and older and by 19% in the age group of 25 years and older. Among the first AMI cases, the risk increased by 7.5% in the age group of 45-64-year olds and by 6.4% in the age group of 25-64-year olds. The relationship between atmospheric temperature and pressure, and AMI occurrence was found to be linear but inverse. An increase in atmospheric pressure by 10 hPa resulted in an increase in risk by 4% among the subjects aged 65 years and more and by 3% among the subjects aged 25 years and more. CONCLUSIONS. Atmospheric temperature and pressure variations had the greatest effect on middle-aged and aging subjects (starting from 45 years). At younger age, the effect of such factors on the AMI risk was considerably lower.

  2. Translational, rotational and vibrational temperatures of a gliding arc discharge at atmospheric pressure air

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas;

    2014-01-01

    Gliding arc discharges have generally been used to generate non-equilibrium plasma at atmospheric pressure. Temperature distributions of a gliding arc are of great interest both for fundamental plasma research and for practical applications. In the presented studies, translational, rotational...... and vibrational temperatures of a gliding arc generated at atmospheric pressure air are investigated. Translational temperatures (about 1100 K) were measured by laser-induced Rayleigh scattering, and two-dimensional temperature imaging was performed. Rotational and vibrational temperatures (about 3600 K and 6700...

  3. Vertical thermal structure of the Venus atmosphere from temperature and pressure measurements

    Energy Technology Data Exchange (ETDEWEB)

    Linkin, V.M.; Blamon, Z.; Lipatov, A.P.; Devyatkin, S.I.; Dyachkov, A.V.; Ignatova, S.I.; Kerzhanovich, V.V.; Malyk, K.; Stadny, V.I.; Sanotskiy, Y.V.

    1986-05-01

    Accurate temperature and pressure measurements were made on the Vega-2 lander during its entire descent. The temperature and pressure at the surface were 733 K and 89.3 bar, respectively. A strong temperature inversion was found in the upper troposphere. Several layers with differing static stability were visible in the atmospheric structure.

  4. Temperature Structure and Atmospheric Circulation of Dry, Tidally Locked Rocky Exoplanets

    CERN Document Server

    Koll, Daniel D B

    2016-01-01

    Next-generation space telescopes will observe the atmospheres of rocky planets orbiting nearby M-dwarfs. Understanding these observations will require well-developed theory in addition to numerical simulations. Here we present theoretical models for the temperature structure and atmospheric circulation of dry, tidally locked rocky exoplanets with grey radiative transfer and test them using a general circulation model (GCM). First, we develop a radiative-convective model that captures surface temperatures of slowly rotating and cool atmospheres. Second, we show that the atmospheric circulation acts as a global heat engine, which places strong constraints on large-scale wind speeds. Third, we develop a radiative-convective-subsiding model which extends our radiative-convective model to hot and thin atmospheres. We find that rocky planets develop large day-night temperature gradients at a ratio of wave-to-radiative timescales up to two orders of magnitude smaller than the value suggested by work on hot Jupiters....

  5. Quantfication of high frequency thermal waves in the martian atmosphere: Analysis of MGS Horizon Sensor atmospheric temperatures

    Science.gov (United States)

    Murphy, J. R.; Martin, T. Z.; Blackmon, M.; Nelli, S.

    2001-11-01

    Stationary and high frequency travelling atmospheric thermal waves on Mars have been quantitatively studied via analyses of temperatures obtained with the Mars Global Surveyor orbiter Horizon Sensor Array (MHSA) instrument. This infrared instrument obtains both in-track and cross-track determinations of martian atmospheric temperature with a vertically broad weighting function. The six local times of coverage provided by these four simultaneous fields of view from MGS's sun-synchronous mapping orbit allow for quantification of eastward and westward travelling diurnal and semi-diurnal atmospheric thermal waves. These high frequency wave (tide) phenomena exhibit seasonal variations due to both changing solar heating and to varying atmospheric dust content. Comparisons with numerical model results illustrate the viability of the MHSA time/space sampling to provide valid determination of the amplitudes and phases of these wave phenomena. The results from these studies are complimentary to the more vertically resolved but less time-of-sol abundant MGS TES temperatures. Results of the MHSA analyses indicate the annual persistence of eastward travelling (asynchronous or 'non-travelling') atmospheric tidal modes, and the sensitivity of tidal amplitudes to both season and dust load. Stationary waves at middle latitudes of both hemispheres exhibit significant seasonal variability, as has previously been inferred from TES data and which is theoretically consistent with thermal wind considerations. The accumulating data being obtained by MGS' instruments, including the MHSA, offer the opportunity to investigate interannual atmospheric variability from a self-consistent set of orbital measurements. Current results will be presented. This work has been funded by NASA's Mars Data Analysis Program.

  6. Mega-heatwave temperatures due to combined soil desiccation and atmospheric heat accumulation

    Science.gov (United States)

    Miralles, Diego G.; Teuling, Adriaan J.; van Heerwaarden, Chiel C.; Vilà-Guerau de Arellano, Jordi

    2014-05-01

    The recent European mega-heatwaves of 2003 and 2010 broke temperature records across Europe. Although events of this magnitude were unprecedented from a historical perspective, they are expected to become common by the end of the century. However, our understanding of extreme heatwave events is limited and their representation in climate models remains imperfect. Here we investigate the physical processes underlying recent mega-heatwaves using satellite and balloon measurements of land and atmospheric conditions from the summers of 2003 in France and 2010 in Russia, in combination with a soil-water-atmosphere model. We find that, in both events, persistent atmospheric pressure patterns induced land-atmosphere feedbacks that led to extreme temperatures. During daytime, heat was supplied by large-scale horizontal advection, warming of an increasingly desiccated land surface and enhanced entrainment of warm air into the atmospheric boundary layer. Overnight, the heat generated during the day was preserved in an anomalous kilometres-deep atmospheric layer located several hundred metres above the surface, available to re-enter the atmospheric boundary layer during the next diurnal cycle. This resulted in a progressive accumulation of heat over several days, which enhanced soil desiccation and led to further escalation in air temperatures. Our findings suggest that the extreme temperatures in mega-heatwaves can be explained by the combined multi-day memory of the land surface and the atmospheric boundary layer.

  7. Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets

    Science.gov (United States)

    Kasting, James F.; Chen, Howard; Kopparapu, Ravi K.

    2015-11-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3D calculations. However, at surface temperatures above 350 K, the stratosphere warms and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a moist greenhouse explanation for loss of water from Venus, or some exoplanet receiving a comparable amount of stellar radiation, remains a viable hypothesis. Temperatures in the upper parts of such atmospheres are well below those estimated for a gray atmosphere, and this factor should be taken into account when performing inverse climate calculations to determine habitable zone boundaries using 1D models.

  8. Stratospheric Temperatures and Water Loss from Moist Greenhouse Atmospheres of Earth-like Planets

    CERN Document Server

    Kasting, James F; Kopparapu, Ravi Kumar

    2015-01-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3-D calculations. However, at surface temperatures above 350 K, the stratosphere warms and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a 'moist greenhouse' explanation for loss of water from Venus, or some exoplanet receiving a comparable amount of stellar radiation, remains a viable hypothesis. Temperatures in the upper parts of such atmospheres are well below those estimated for a gray atmosphere, and this factor should be taken into account when performing 'inverse' climate calculations to determine habitable zone boundaries using 1-D models.

  9. STRATOSPHERIC TEMPERATURES AND WATER LOSS FROM MOIST GREENHOUSE ATMOSPHERES OF EARTH-LIKE PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Kasting, James F.; Kopparapu, Ravi K. [Department of Geosciences, The Pennsylvania State University, State College, PA 16801 (United States); Chen, Howard, E-mail: jfk4@psu.edu, E-mail: hwchen@bu.edu [Department of Astronomy, Boston University, 725 Commonwealth Ave., Boston, MA 02215 (United States)

    2015-11-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3D calculations. However, at surface temperatures above 350 K, the stratosphere warms and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a moist greenhouse explanation for loss of water from Venus, or some exoplanet receiving a comparable amount of stellar radiation, remains a viable hypothesis. Temperatures in the upper parts of such atmospheres are well below those estimated for a gray atmosphere, and this factor should be taken into account when performing inverse climate calculations to determine habitable zone boundaries using 1D models.

  10. Dependence of global temperatures on atmospheric CO2 and solar irradiance

    OpenAIRE

    David J. Thomson

    1997-01-01

    Changes in global average temperatures and of the seasonal cycle are strongly coupled to the concentration of atmospheric CO2. I estimate transfer functions from changes in atmospheric CO2 and from changes in solar irradiance to hemispheric temperatures that have been corrected for the effects of precession. They show that changes from CO2 over the last century are about three times larger than those from changes in solar irradiance. The increase in global average ...

  11. A Minimized Mutual Information retrieval for simultaneous atmospheric pressure and temperature

    OpenAIRE

    Koner, Prabhat K.; Drummond, James R.

    2010-01-01

    The primary focus of the Mars Trace Gas Orbiter (TGO) collaboration between NASA and ESA is the detection of the temporal and spatial variation of the atmospheric trace gases using a solar occultation Fourier transform spectrometer. To retrieve any trace gas mixing ratios from these measurements, the atmospheric pressure and temperature have to be known accurately. Thus, a prototype retrieval model for the determination of pressure and temperature from a broadband high resolution infrared Fou...

  12. Altitude dependence of atmospheric temperature trends: Climate models versus observation

    CERN Document Server

    Douglass, D H; Singer, F

    2004-01-01

    As a consequence of greenhouse forcing, all state of the art general circulation models predict a positive temperature trend that is greater for the troposphere than the surface. This predicted positive trend increases in value with altitude until it reaches a maximum ratio with respect to the surface of as much as 1.5 to 2.0 at about 200 to 400 hPa. However, the temperature trends from several independent observational data sets show decreasing as well as mostly negative values. This disparity indicates that the three models examined here fail to account for the effects of greenhouse forcings.

  13. Using optimal estimation method for upper atmospheric Lidar temperature retrieval

    Science.gov (United States)

    Zou, Rongshi; Pan, Weilin; Qiao, Shuai

    2016-07-01

    Conventional ground based Rayleigh lidar temperature retrieval use integrate technique, which has limitations that necessitate abandoning temperatures retrieved at the greatest heights due to the assumption of a seeding value required to initialize the integration at the highest altitude. Here we suggests the use of a method that can incorporate information from various sources to improve the quality of the retrieval result. This approach inverts lidar equation via optimal estimation method(OEM) based on Bayesian theory together with Gaussian statistical model. It presents many advantages over the conventional ones: 1) the possibility of incorporating information from multiple heterogeneous sources; 2) provides diagnostic information about retrieval qualities; 3) ability of determining vertical resolution and maximum height to which the retrieval is mostly independent of the a priori profile. This paper compares one-hour temperature profiles retrieved using conventional and optimal estimation methods at Golmud, Qinghai province, China. Results show that OEM results show a better agreement with SABER profile compared with conventional one, in some region it is much lower than SABER profile, which is a very different results compared with previous studies, further studies are needed to explain this phenomenon. The success of applying OEM on temperature retrieval is a validation for using as retrieval framework in large synthetic observation systems including various active remote sensing instruments by incorporating all available measurement information into the model and analyze groups of measurements simultaneously to improve the results.

  14. Precision analysis on the weighted mean temperature of the atmosphere grid data offered by GGOS Atmosphere in Xinjiang

    Science.gov (United States)

    Liu, Lilong; Li, Junyu; Chen, Xiangping; Cai, Chenghui

    2015-12-01

    As the fact that most of the ground-based GPS lacks of the detection of the upper-air meteorological data, thus the application of ground-based GPS sensing of water vapor technology has been limited due to the inaccurately calculated weighted mean temperature. In that case, this paper has studied and analyzed the methods of obtaining weighted mean temperature by deriving the data from GGOS Atmosphere weighted mean temperature grid data in Xinjiang. By using the radiosonde data, this paper has evaluated the accuracy of the weighted mean temperature(GTm) derived from GGOS atmosphere weighted mean temperature grid data and considering the seasonal and geographic factors , we employed a correction model to fit the residuals of GTm. Results show that the GTm derived from mean value interpolation and corrected by correction model meet the requirements of ground-based GPS precision sensing of Water Vapor in Xinjiang ; The inner average precision RMSD is 2.33K , MAE is 1.80 K; The outer average precision RMSD is 2.36K , MAE is 1.85 K.

  15. Simultaneous wind and temperature measurements in the middle atmosphere with a twin Doppler lidar

    Science.gov (United States)

    Hildebrand, Jens; Baumgarten, Gerd; Fiedler, Jens; Lübken, Franz-Josef

    2016-04-01

    Winds play an important role for the filtering of gravity waves traveling from the ground to higher altitudes. They control the propagation of gravity waves and the amount of transported energy and momentum. The thermal structure of the atmosphere determines its stability, hence the buoyancy frequency. Therefore, knowing winds and temperatures in the middle atmosphere is crucial to study and interpret atmospheric dynamics comprehensively. Both temperature and wind affect the propagation of infrasound waves through the middle atmosphere. Observing winds and temperatures in the middle atmosphere on routine basis is challenging since a large part of this altitude range is not accessible by radars or satellites. Using the Doppler Rayleigh Iodine Spectrometer DoRIS, our Rayleigh/Mie/Raman lidar at the Arctic station ALOMAR in Northern Norway (69°N, 16°E) is capable to measure winds and temperatures simultaneously in the middle atmosphere between about 20 and 80 km altitude. Since two independently steerable telescopes are used, we can derive two wind components at once. Winds and temperatures are measured even under daylight conditions, yielding observations spanning multiple days, which is essential for, e.g., gravity-wave studies. We will present results from case studies and a larger data set covering winter situations between 2012 and 2015, including stratospheric warmings and periods of enhanced gravity wave activity.

  16. SUMER: Temperatures, densities, and velocities in the outer solar atmosphere

    Science.gov (United States)

    Lemaire, Philippe; Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.; Grewing, M.; Huber, M. C. E.; Jordan, Stuart D.; Kuehne, M.; Marsch, Eckart

    1992-01-01

    The SUMER (Solar Ultraviolet Measurement of Emitted Radiation) instrumentation that will be mounted on the SOHO (Solar and Heliospheric Observatory) spacecraft is in development. It has some capability of improving the solar angular resolution and the spectral resolution already obtained in the far UV to the extreme UV, corresponding to the temperature range between 10,000 and a few 1,000,000 K. Some insights into the SUMER spectrometer, developed to study the dynamics and to infer temperatures and densities of the low corona and the chromosphere-corona transition zone in using the 50 to 160 nm wavelength range, are given. The SUMER scientific goals and the techniques used are outlined. The instrumentation and the expected performances are described. The way the observations can be conducted is emphasized and the operation of SUMER in coordination with other SOHO instrumentations and in cooperation with ground based observations is explained.

  17. Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) data processing and atmospheric temperature and trace gas retrieval

    Science.gov (United States)

    Riese, M.; Spang, R.; Preusse, P.; Ern, M.; Jarisch, M.; Offermann, D.; Grossmann, K. U.

    1999-07-01

    The Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiment aboard the Shuttle Pallet Satellite (SPAS) was successfully flown in early November 1994 (STS 66) and in August 1997 (STS 85). This paper focuses on the first flight of the instrument, which was part of the Atmospheric Laboratory for Application and Science 3 (ATLAS 3) mission of NASA. During a free flying period of 7 days, limb scan measurements of atmospheric infrared emissions were performed in the 4 to 71 μm wavelength region. For improved horizontal resolution, three telescopes (viewing directions) were used that sensed the atmosphere simultaneously. Atmospheric pressures, temperatures, and volume mixing ratios of various trace gases were retrieved from the radiance data by using a fast onion-peeling retrieval technique. This paper gives an overview of the data system including the raw data processing and the temperature and trace gas profile retrieval. Examples of version 1 limb radiance data (level 1 product) and version 1 mixing ratios (level 2 product) of ozone, ClONO2, and CFC-11 are given. A number of important atmospheric transport processes can already be identified in the level 1 limb radiance data. Radiance data of the lower stratosphere (18 km) indicate strong upwelling in some equatorial regions, centered around the Amazon, Congo, and Indonesia. Respective data at the date line are consistent with convection patterns associated with El Niño. Very low CFC-11 mixing ratios occur inside the South Polar vortex and cause low radiance values in a spectral region sensitive to CFC-11 emissions. These low values are a result of considerable downward transport of CFC-11 poor air that occurred during the winter months. Limb radiance profiles and retrieved mixing ratio profiles of CFC-11 indicate downward transport over ˜5 km. The accuracy of the retrieved version 1 mixing ratios is rather different for the various trace gases. In the middle atmosphere the estimated

  18. Low-temperature sintering process for UO2 pellets in partially-oxidative atmosphere

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-dong; GAO Jia-cheng; WANG Yong; CHANG Xin

    2008-01-01

    Low-temperature sintering(LTS) experiments of UO2 pellets and their results were reported. Moreover, a routine process of LTS for UO2 pellets was primarily established. Being sintered at 1 400 ℃ for 3 h in a partially-oxidative atmosphere, the relative density of the pellet can be up to around 94%. Pellets with such a high density are of benefit for following-up reduction-sintering processes. Orthogonal test indicates that the importance of factors affecting the density decreases in the sequence of partial-oxidative sintering temperature and time, reduction-sintering time and temperature, and sintering atmosphere. It is found that it is helpful to introducing a small amount of water vapor into the sintering atmosphere during the latter stage. It is believed that it is the key factor to raise the O/U ratio of original powder in order to improve the properties of the low-temperature sintered pellets.

  19. VUV-absorption cross section of CO2 at high temperatures and impact on exoplanet atmospheres

    Directory of Open Access Journals (Sweden)

    Venot Olivia

    2014-02-01

    Full Text Available Ultraviolet (UV absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar system. Transiting exoplanets whose atmospheres can now be studied by transit spectroscopy receive extremely strong UV fluxes and have typical temperatures ranging from 400 to 2500 K. At these temperatures, UV photolysis cross section data are severely lacking. Our goal is to provide high-temperature absorption cross sections and their temperature dependency for important atmospheric compounds. This study is dedicated to CO2, which is observed and photodissociated in exoplanet atmospheres. We performed these measurements for the 115 - 200 nm range at 300, 410, 480, and 550 K. In the 195 - 230 nm range, we worked at seven temperatures between 465 and 800 K. We found that the absorption cross section of CO2 is very sensitive to temperature, especially above 160 nm. Within the studied range of temperature, the CO2 cross section can vary by more than two orders of magnitude. This, in particular, makes the absorption of CO2 significant up to wavelengths as high as 230 nm, while it is negligible above 200 nm at 300 K. To investigate the influence of these new data on the photochemistry of exoplanets, we implemented the measured cross section into a 1D photochemical model. The model predicts that accounting for this temperature dependency of CO2 cross section can affect the computed abundances of NH3, CO2, and CO by one order of magnitude in the atmospheres of hot Jupiter and hot Neptune.

  20. Seasonal variability of diurnal temperature range in Egypt with links to atmospheric circulations and sea surface temperature

    Science.gov (United States)

    El Kenawy, A.; Lopez Moreno, J. I.; Vicente-Serrano, S.

    2010-09-01

    The diurnal temperature range (DTR) is an important climate-change variable. Seasonal and annual variability of DTR in Egypt was investigated based on a monthly dataset of 40 observatories distributing across the country. The trends were calculated using the Rho spearman rank test at the 95 % level of significance. The trends at the independent individual scale were compared with a regional series created for the whole country following the Thiessen polygon approach. A cross-tabulation analysis was performed between the trends of the DTR and the trends of maximum and minimum temperatures to account for directional causes of variability of the DTR at seasonal and annual scales. The physical processes controlling the DTR variability were also assessed in terms of large atmospheric circulations representing in the indices of the North Atlantic Oscillation (NAO), the East Atlantic (EA) pattern, El Niño Southern Oscillation (ENSO) index and the EAWR (East Atlantic/West Russia) Pattern. Also, the variability of the DTR was linked with anomaly of Sea Surface Temperature (SST). A cooling trend was observed in Egypt with strong behavior in winter and summer rather than fall and spring. The upwarding trend of the mean minimum temperature was mainly responsible for variability of the DTR rather than the mean maximum temperature. Also, the EA and the EAWR indices were the main indices accounted for most of variation in the DTR in Egypt, particularly in summer. Key words: trend analysis, temperature variability, Diurnal temperature range, atmospheric circulation, sea surface temperature, Egypt.

  1. Impedance measurements on Au microelectrodes using controlled atmosphere high temperature scanning probe microscope

    DEFF Research Database (Denmark)

    Wu, Yuehua; Hansen, Karin Vels; Jacobsen, Torben;

    2011-01-01

    High temperature impedance measurements on Au microelectrodes deposited on polished yttria stabilized zirconia (YSZ) pellets were demonstrated using a newly designed controlled atmosphere high temperature scanning probe microscope (CAHT-SPM). Probes based on Pt0.8Ir0.2 were fabricated and employed....... The impedance spectra of circular Au microelectrodes down to 8μm in diameter at different temperatures were successfully obtained. The CAHT-SPM presented in this paper is capable of obtaining topography images, conductivity images and impedance spectra in-situ in a temperature range from room temperature...

  2. Temperature Structure and Atmospheric Circulation of Dry Tidally Locked Rocky Exoplanets

    Science.gov (United States)

    Koll, Daniel D. B.; Abbot, Dorian S.

    2016-07-01

    Next-generation space telescopes will observe the atmospheres of rocky planets orbiting nearby M-dwarfs. Understanding these observations will require well-developed theory in addition to numerical simulations. Here we present theoretical models for the temperature structure and atmospheric circulation of dry, tidally locked rocky exoplanets with gray radiative transfer and test them using a general circulation model (GCM). First, we develop a radiative-convective (RC) model that captures surface temperatures of slowly rotating and cool atmospheres. Second, we show that the atmospheric circulation acts as a global heat engine, which places strong constraints on large-scale wind speeds. Third, we develop an RC-subsiding model which extends our RC model to hot and thin atmospheres. We find that rocky planets develop large day-night temperature gradients at a ratio of wave-to-radiative timescales up to two orders of magnitude smaller than the value suggested by work on hot Jupiters. The small ratio is due to the heat engine inefficiency and asymmetry between updrafts and subsidence in convecting atmospheres. Fourth, we show, using GCM simulations, that rotation only has a strong effect on temperature structure if the atmosphere is hot or thin. Our models let us map out atmospheric scenarios for planets such as GJ 1132b, and show how thermal phase curves could constrain them. Measuring phase curves of short-period planets will require similar amounts of time on the James Webb Space Telescope as detecting molecules via transit spectroscopy, so future observations should pursue both techniques.

  3. Temperature variations in Titan's upper atmosphere: Impact on Cassini/Huygens

    Directory of Open Access Journals (Sweden)

    B. Kazeminejad

    2005-06-01

    Full Text Available Temperature variations of Titan's upper atmosphere due to the plasma interaction of the satellite with Saturn's magnetosphere and Titan's high altitude monomer haze particles can imply an offset of up to ±30K from currently estimated model profiles. We incorporated these temperature uncertainties as an offset into the recently published Vervack et al. (2004 (Icarus, Vol. 170, 91-112 engineering model and derive extreme case (i.e. minimum and maximum profiles temperature, pressure, and density profiles. We simulated the Huygens probe hypersonic entry trajectory and obtain, as expected, deviations of the probe trajectory for the extreme atmosphere models compared to the simulation based on the nominal one. These deviations are very similar to the ones obtained with the standard Yelle et al. (1997 (ESA SP-1177 profiles. We could confirm that the difference in aerodynamic drag is of an order of magnitude that can be measured by the probe science accelerometer. They represent an important means for the reconstruction of Titan's upper atmospheric properties. Furthermore, we simulated a Cassini low Titan flyby trajectory. No major trajectory deviations were found. The atmospheric torques due to aerodynamic drag, however, are twice as high for our high temperature profile as the ones obtained with the Yelle maximum profile and more than 5 times higher than the worst case estimations from the Cassini project. We propose to use the Cassini atmospheric torque measurements during its low flybys to derive the atmospheric drag and to reconstruct Titan's upper atmosphere density, pressure, and temperature. The results could then be compared to the reconstructed profiles obtained from Huygens probe measurements. This would help to validate the probe measurements and decrease the error bars.

  4. A Useful Tool for Atmospheric Correction and Surface Temperature Estimation of Landsat Infrared Thermal Data

    Science.gov (United States)

    Rivalland, Vincent; Tardy, Benjamin; Huc, Mireille; Hagolle, Olivier; Marcq, Sébastien; Boulet, Gilles

    2016-04-01

    Land Surface temperature (LST) is a critical variable for studying the energy and water budgets at the Earth surface, and is a key component of many aspects of climate research and services. The Landsat program jointly carried out by NASA and USGS has been providing thermal infrared data for 40 years, but no associated LST product has been yet routinely proposed to community. To derive LST values, radiances measured at sensor-level need to be corrected for the atmospheric absorption, the atmospheric emission and the surface emissivity effect. Until now, existing LST products have been generated with multi channel methods such as the Temperature/Emissivity Separation (TES) adapted to ASTER data or the generalized split-window algorithm adapted to MODIS multispectral data. Those approaches are ill-adapted to the Landsat mono-window data specificity. The atmospheric correction methodology usually used for Landsat data requires detailed information about the state of the atmosphere. This information may be obtained from radio-sounding or model atmospheric reanalysis and is supplied to a radiative transfer model in order to estimate atmospheric parameters for a given coordinate. In this work, we present a new automatic tool dedicated to Landsat thermal data correction which improves the common atmospheric correction methodology by introducing the spatial dimension in the process. The python tool developed during this study, named LANDARTs for LANDsat Automatic Retrieval of surface Temperature, is fully automatic and provides atmospheric corrections for a whole Landsat tile. Vertical atmospheric conditions are downloaded from the ERA Interim dataset from ECMWF meteorological organization which provides them at 0.125 degrees resolution, at a global scale and with a 6-hour-time step. The atmospheric correction parameters are estimated on the atmospheric grid using the commercial software MODTRAN, then interpolated to 30m resolution. We detail the processing steps

  5. Trends in atmospheric patterns conducive to seasonal precipitation and temperature extremes in California.

    Science.gov (United States)

    Swain, Daniel L; Horton, Daniel E; Singh, Deepti; Diffenbaugh, Noah S

    2016-04-01

    Recent evidence suggests that changes in atmospheric circulation have altered the probability of extreme climate events in the Northern Hemisphere. We investigate northeastern Pacific atmospheric circulation patterns that have historically (1949-2015) been associated with cool-season (October-May) precipitation and temperature extremes in California. We identify changes in occurrence of atmospheric circulation patterns by measuring the similarity of the cool-season atmospheric configuration that occurred in each year of the 1949-2015 period with the configuration that occurred during each of the five driest, wettest, warmest, and coolest years. Our analysis detects statistically significant changes in the occurrence of atmospheric patterns associated with seasonal precipitation and temperature extremes. We also find a robust increase in the magnitude and subseasonal persistence of the cool-season West Coast ridge, resulting in an amplification of the background state. Changes in both seasonal mean and extreme event configurations appear to be caused by a combination of spatially nonuniform thermal expansion of the atmosphere and reinforcing trends in the pattern of sea level pressure. In particular, both thermal expansion and sea level pressure trends contribute to a notable increase in anomalous northeastern Pacific ridging patterns similar to that observed during the 2012-2015 California drought. Collectively, our empirical findings suggest that the frequency of atmospheric conditions like those during California's most severely dry and hot years has increased in recent decades, but not necessarily at the expense of patterns associated with extremely wet years.

  6. Sea ice edge position impact on the atmospheric boundary layer temperature structure

    Science.gov (United States)

    Khavina, Elena; Repina, Irina

    2016-04-01

    Processes happening in the Arctic region nowadays strongly influence global climate system; the polar amplification effect can be considered one of the main indicators of ongoing changes. Dramatic increase in amount of ice-free areas in the Arctic Ocean, which took place in 2000s, is one of the most significant examples of climate system dynamic in polar region. High amplitude of changes in Arctic climate, both observed and predicted, and existing inaccuracies of climate and weather forecasting models, enforce the development of a more accurate one. It is essential to understand the physics of the interaction between atmosphere and ocean in the Northern Polar area (particularly in boundary layer of the atmosphere) to improve the models. Ice conditions have a great influence on the atmospheric boundary layer in the Arctic. Sea ice inhibits the heat exchange between atmosphere and ocean water during the polar winter, while the heat exchange above the ice-free areas increases rapidly. Due to those significant temperature fluctuations, turbulence of heat fluxes grows greatly. The most intensive interaction takes place at marginal ice zones, especially in case of the cold outbreak - intrusion of cooled air mass from the ice to free water area. Still, thermal structure and dynamic of the atmosphere boundary layer are not researched and described thoroughly enough. Single radio sounding observations from the planes being done, bur they do not provide high-resolution data which is necessary for study. This research is based on continuous atmosphere boundary layer temperature and sea ice observation collected in the Arctic Ocean during the two NABOS expeditions in August and September in 2013 and 2015, as well as on ice conditions satellite data (NASA TEAM 2 and VASIA 2 data processing). Atmosphere temperature data has been obtained with Meteorological Temperature Profiler MTP-5 (ATTEX, Russia). It is a passive radiometer, which provides continuous data of atmospheric

  7. Dynamic responses of atmospheric carbon dioxide concentration to global temperature changes between 1850 and 2010

    Science.gov (United States)

    Wang, Weile; Nemani, Ramakrishna

    2016-02-01

    Changes in Earth's temperature have significant impacts on the global carbon cycle that vary at different time scales, yet to quantify such impacts with a simple scheme is traditionally deemed difficult. Here, we show that, by incorporating a temperature sensitivity parameter (1.64 ppm yr-1 °C-1) into a simple linear carbon-cycle model, we can accurately characterize the dynamic responses of atmospheric carbon dioxide (CO2) concentration to anthropogenic carbon emissions and global temperature changes between 1850 and 2010 ( r 2 > 0.96 and the root-mean-square error CO2 concentration (~15 ppm °C-1), generally consistent with previous estimates based on reconstructed CO2 and climate records over the Little Ice Age. Our results suggest that recent increases in global surface temperatures, which accelerate the release of carbon from the surface reservoirs into the atmosphere, have partially offset surface carbon uptakes enhanced by the elevated atmospheric CO2 concentration and slowed the net rate of atmospheric CO2 sequestration by global land and oceans by ~30% since the 1960s. The linear modeling framework outlined in this paper thus provides a useful tool to diagnose the observed atmospheric CO2 dynamics and monitor their future changes.

  8. Marketability of ready-to-eat cactus pear as affected by temperature and modified atmosphere.

    Science.gov (United States)

    Cefola, Maria; Renna, Massimiliano; Pace, Bernardo

    2014-01-01

    In order to increase the diffusion of cactus pear fruits, in this study, the proper maturity index for peeling and processing them as ready-to-eat product was evaluated and characterized. Thereafter, the effects of different storage temperatures and modified atmosphere conditions on the marketability of ready-to-eat cactus pear were studied. The storage of ready-to-eat fruits at 4 °C in both passive (air) and semi-active (10 kPa O2 and 10 kPa CO2) modified atmosphere improved the marketability by 30%, whereas the storage at 8 °C caused a dangerous reduction in O2 partial pressure inside modified atmosphere packages, due to fruits' increased metabolic activity. A very low level of initial microbial growth was detected, while a severe increase in mesophilic and psychrophilic bacteria was shown in control samples at both temperatures during storage; an inhibitory effect of modified atmosphere on microbial growth was also observed. In conclusion, modified atmosphere improved only the marketability of fruits stored at 4 °C; whereas the storage at 8 °C resulted in deleterious effects on the ready-to-eat fruits, whether stored in air or in modified atmosphere.

  9. High-Temperature, Dual-Atmosphere Corrosion of Solid-Oxide Fuel Cell Interconnects

    Science.gov (United States)

    Gannon, Paul; Amendola, Roberta

    2012-12-01

    High-temperature corrosion of ferritic stainless steel (FSS) surfaces can be accelerated and anomalous when it is simultaneously subjected to different gaseous environments, e.g., when separating fuel (hydrogen) and oxidant (air) streams, in comparison with single-atmosphere exposures, e.g., air only. This so-called "dual-atmosphere" exposure is realized in many energy-conversion systems including turbines, boilers, gasifiers, heat exchangers, and particularly in intermediate temperature (600-800°C) planar solid-oxide fuel cell (SOFC) stacks. It is generally accepted that hydrogen transport through the FSS (plate or tube) and its subsequent integration into the growing air-side surface oxide layer can promote accelerated and anomalous corrosion—relative to single-atmosphere exposure—via defect chemistry changes, such as increased cation vacancy concentrations, decreased oxygen activity, and steam formation within the growing surface oxide layers. Establishment of a continuous and dense surface oxide layer on the fuel side of the FSS can inhibit hydrogen transport and the associated effects on the air side. Minor differences in FSS composition, microstructure, and surface conditions can all have dramatic influences on dual-atmosphere corrosion behaviors. This article reviews high-temperature, dual-atmosphere corrosion phenomena and discusses implications for SOFC stacks, related applications, and future research.

  10. Estimation of the Ocean Skin Temperature using the NASA GEOS Atmospheric Data Assimilation System

    Science.gov (United States)

    Koster, Randal D.; Akella, Santha; Todling, Ricardo; Suarez, Max

    2016-01-01

    This report documents the status of the development of a sea surface temperature (SST) analysis for the Goddard Earth Observing System (GEOS) Version-5 atmospheric data assimilation system (ADAS). Its implementation is part of the steps being taken toward the development of an integrated earth system analysis. Currently, GEOS-ADAS SST is a bulk ocean temperature (from ocean boundary conditions), and is almost identical to the skin sea surface temperature. Here we describe changes to the atmosphere-ocean interface layer of the GEOS-atmospheric general circulation model (AGCM) to include near surface diurnal warming and cool-skin effects. We also added SST relevant Advanced Very High Resolution Radiometer (AVHRR) observations to the GEOS-ADAS observing system. We provide a detailed description of our analysis of these observations, along with the modifications to the interface between the GEOS atmospheric general circulation model, gridpoint statistical interpolation-based atmospheric analysis and the community radiative transfer model. Our experiments (with and without these changes) show improved assimilation of satellite radiance observations. We obtained a closer fit to withheld, in-situ buoys measuring near-surface SST. Evaluation of forecast skill scores corroborate improvements seen in the observation fits. Along with a discussion of our results, we also include directions for future work.

  11. Coupling of surface temperatures and atmospheric CO_2 concentrations during the Palaeozoic era

    OpenAIRE

    Came, Rosemarie E.; Eiler, John M.; Veizer, Ján; Azmy, Karem; Brand, Uwe; Weidman, Christopher R.

    2007-01-01

    Atmospheric carbon dioxide concentrations seem to have been several times modern levels during much of the Palaeozoic era (543–248 million years ago), but decreased during the Carboniferous period to concentrations similar to that of today. Given that carbon dioxide is a greenhouse gas, it has been proposed that surface temperatures were significantly higher during the earlier portions of the Palaeozoic era. A reconstruction of tropical sea surface temperatures based on the δ^(18)O of carbona...

  12. Neural Network Based Retrieval of Atmospheric Temperature Profile Using AMSU-A Observations

    Directory of Open Access Journals (Sweden)

    R. K. Gangwar

    2014-01-01

    Full Text Available The present study describes artificial neural network (ANN based approach for the retrieval of atmospheric temperature profiles from AMSU-A microwave temperature sounder. The nonlinear relationship between the temperature profiles and satellite brightness temperatures dictates the use of ANN, which is inherently nonlinear in nature. Since latitudinal variation of temperature is dominant one in the Earth’s atmosphere, separate network configurations have been established for different latitudinal belts, namely, tropics, mid-latitudes, and polar regions. Moreover, as surface emissivity in the microwave region of electromagnetic spectrum significantly influences the radiance (or equivalently the brightness temperature at the satellite altitude, separate algorithms have been developed for land and ocean for training the networks. Temperature profiles from National Center for Environmental Prediction (NCEP analysis and brightness temperature observations of AMSU-A onboard NOAA-19 for the year 2010 have been used for training of the networks. Further, the algorithm has been tested on the independent dataset comprising several months of 2012 AMSU-A observations. Finally, an error analysis has been performed by comparing retrieved profiles with collocated temperature profiles from NCEP. Errors in the tropical region are found to be less than those in the mid-latitude and polar regions. Also, in each region the errors over ocean are less than the corresponding ones over land.

  13. Implications of atmospheric conditions for analysis of surface temperature variability derived from landscape-scale thermography

    Science.gov (United States)

    Hammerle, Albin; Meier, Fred; Heinl, Michael; Egger, Angelika; Leitinger, Georg

    2016-08-01

    Thermal infrared (TIR) cameras perfectly bridge the gap between (i) on-site measurements of land surface temperature (LST) providing high temporal resolution at the cost of low spatial coverage and (ii) remotely sensed data from satellites that provide high spatial coverage at relatively low spatio-temporal resolution. While LST data from satellite (LSTsat) and airborne platforms are routinely corrected for atmospheric effects, such corrections are barely applied for LST from ground-based TIR imagery (using TIR cameras; LSTcam). We show the consequences of neglecting atmospheric effects on LSTcam of different vegetated surfaces at landscape scale. We compare LST measured from different platforms, focusing on the comparison of LST data from on-site radiometry (LSTosr) and LSTcam using a commercially available TIR camera in the region of Bozen/Bolzano (Italy). Given a digital elevation model and measured vertical air temperature profiles, we developed a multiple linear regression model to correct LSTcam data for atmospheric influences. We could show the distinct effect of atmospheric conditions and related radiative processes along the measurement path on LSTcam, proving the necessity to correct LSTcam data on landscape scale, despite their relatively low measurement distances compared to remotely sensed data. Corrected LSTcam data revealed the dampening effect of the atmosphere, especially at high temperature differences between the atmosphere and the vegetated surface. Not correcting for these effects leads to erroneous LST estimates, in particular to an underestimation of the heterogeneity in LST, both in time and space. In the most pronounced case, we found a temperature range extension of almost 10 K.

  14. Douglas-fir seedlings exhibit metabolic responses to increased temperature and atmospheric drought.

    Directory of Open Access Journals (Sweden)

    Kirstin Jansen

    Full Text Available In the future, periods of strongly increased temperature in concert with drought (heat waves will have potentially detrimental effects on trees and forests in Central Europe. Norway spruce might be at risk in the future climate of Central Europe. However, Douglas-fir is often discussed as an alternative for the drought and heat sensitive Norway spruce, because some provenances are considered to be well adapted to drier and warmer conditions. In this study, we identified the physiological and growth responses of seedlings from two different Douglas-fir provenances to increased temperature and atmospheric drought during a period of 92 days. We analysed (i plant biomass, (ii carbon stable isotope composition as an indicator for time integrated intrinsic water use efficiency, (iii apparent respiratory carbon isotope fractionation as well as (iv the profile of polar low molecular metabolites. Plant biomass was only slightly affected by increased temperatures and atmospheric drought but the more negative apparent respiratory fractionation indicated a temperature-dependent decrease in the commitment of substrate to the tricarboxylic acid cycle. The metabolite profile revealed that the simulated heat wave induced a switch in stress protecting compounds from proline to polyols. We conclude that metabolic acclimation successfully contributes to maintain functioning and physiological activity in seedlings of both Douglas-fir provenances under conditions that are expected during heat waves (i.e. elevated temperatures and atmospheric drought. Douglas-fir might be a potentially important tree species for forestry in Central Europe under changing climatic conditions.

  15. Long-term air temperature variation in the Karkonosze mountains according to atmospheric circulation

    Science.gov (United States)

    Migała, Krzysztof; Urban, Grzegorz; Tomczyński, Karol

    2016-07-01

    The results of meteorological measurements carried out continuously on Mt Śnieżka in Karkonosze mountains since 1880 well document the warming observed on a global scale. Data analysis indicates warming expressed by an increase in the mean annual air temperature of 0.8 °C/100 years. A much higher temperature increase was recorded in the last two decades at the turn of the twenty-first century. Mean decade air temperatures increased from -0.1 to 1.5 °C. It has been shown that there are relationships between air temperature at Mt Śnieżka and global mechanisms of atmospheric and oceanic circulation. Thermal conditions of the Karkonosze (Mt Śnieżka) accurately reflect global climate trends and impact of the North Atlantic Oscillation (NAO) index, macrotypes of atmospheric circulation in Europe (GWL) and Atlantic Multidecadal Oscillation (AMO). The increase in air temperature during the 1989-2012 solar magnetic cycle may reveal a synergy effect to which astrophysical effects and atmospheric and oceanic circulation effects contribute, modified by constantly increasing anthropogenic factors.

  16. Rotational and Vibrational Temperatures of Atmospheric Double Arc Argon-Nitrogen Plasma

    Institute of Scientific and Technical Information of China (English)

    YAN Jian-Hua; TU Xin; MA Zeng-Yi; CEN Ke-Fa; B.G.Chéron

    2007-01-01

    The spectroscopic technique is employed to study the emission of atmospheric argon-nitrogen plasma jet generated by an original dc double anode plasma torch. The molecular bands of the N(+2) first negative system are observed at the torch exit and chosen to evaluate the rotational and vibrational temperatures in comparison with the simulated spectra. The excitation temperature (Texc≈9600 K) is determined from the Boltzmann plot method. The results show that the rotational, vibrational, electron and kinetic temperatures are in good agreement with one another, which indicates that the core region of atmospheric double arc argon-nitrogen plasma jet at the torch exit is close to the local thermodynamic equilibrium state under our experimental conditions.

  17. A Minimized Mutual Information retrieval for simultaneous atmospheric pressure and temperature

    CERN Document Server

    Koner, Prabhat K

    2010-01-01

    The primary focus of the Mars Trace Gas Orbiter (TGO) collaboration between NASA and ESA is the detection of the temporal and spatial variation of the atmospheric trace gases using a solar occultation Fourier transform spectrometer. To retrieve any trace gas mixing ratios from these measurements, the atmospheric pressure and temperature have to be known accurately. Thus, a prototype retrieval model for the determination of pressure and temperature from a broadband high resolution infrared Fourier Transform spectrometer experiment with the Sun as a source on board a spacecraft orbiting the planet Mars is presented. It is found that the pressure and temperature can be uniquely solved from remote sensing spectroscopic measurements using a Regularized Total Least Squares method and selected pairs of micro-windows without any a-priori information of the state space parameters and other constraints. The selection of the pairs of suitable micro-windows is based on the information content analysis. A comparative info...

  18. Ocean and atmosphere coupling, connection between sub-polar Atlantic air temperature, Icelandic minimum and temperature in Serbia

    Directory of Open Access Journals (Sweden)

    Milovanović Boško

    2009-01-01

    Full Text Available In the presented paper correlation between the northern part of the Atlantic ocean (belt between 50-65°N and the atmospheric pressure is examined. Connection between the ocean temperature and atmospheric pressure is the most obvious in the El Nino southern oscillation mechanism. Thus, so far it is not known that such a mechanism exist in the Atlantic ocean. The main accent in the presented paper is focused on the connection between Iceland low and the sea surface temperature (SST in the subpolar part of the Atlantic ocean (used data are in grid 5x5°. By hierarchical cluster analysis five relatively unified clusters of sea surface temperatures grid cells are defined. By multiple linear regression, we examined the correlation between each of the depicted clusters with position and intensity of Iceland low, and identified the most important grid cells inside every cluster. The analysis of the relation between Iceland low and air temperature in Serbia and Belgrade has shown the strongest correlation for the longitude of this centre of action. .

  19. High Temperature Corrosion of Water Wall Materials T23 and T24 in Simulated Furnace Atmospheres

    Institute of Scientific and Technical Information of China (English)

    赵钦新; 张知翔; 成丁南; 王云刚; 邓翔

    2012-01-01

    Candidate materials for water wall of supercritical and ultra-supercritical utility boilers,T23 and T24,were chosen as the experimental samples and exposed to oxidizing atmosphere,reducing atmosphere and oxidizing/reducing alternating atmosphere separately.The corrosion temperature was 450-550?C.The effects of oxygen con-tent and temperature on the corrosion in reducing atmosphere and alternating atmosphere were investigated.The scanning electron microscope(SEM) and energy dispersive spectrometer(EDS) were used to examine the corroded samples.The results show that the corrosion kinetics of T23 and T24 can be described by the double logarithmic equation and parabolic equation respectively.To describe the corrosion of materials accurately it is not sufficient to analyze the macro-mass gain and the macro-thickness of the corroded layer only,but the EDS should be applied to examine the migration depth of corrosive elements O and S.It is revealed that the corrosion becomes more severe when H2S is present in the corrosive gas.S is more active than O,and Cr can reduce the migration of oxygen but not S.The combination corrosion of S and O and pure [S] has a stronger corrodibility than pure H2S.T24 suffers the most severe corrosion at oxygen content of 0.8%.Corrosion is aggravated when the corrosion temperature is above 450 ℃ in the alternating atmosphere.T23 has better corrosion resistance than T24 and W contributes a lot to the corrosion resistance of T23.

  20. Temporal Evolution of the Size and Temperature of Betelgeuse's Extended Atmosphere

    CERN Document Server

    O'Gorman, Eamon; Brown, Alexander; Guinan, Edward F; Richards, Anita M S; Vlemmings, Wouter; Wasatonic, Richard

    2015-01-01

    We use the Very Large Array (VLA) in the A configuration with the Pie Town (PT) Very Long Baseline Array (VLBA) antenna to spatially resolve the extended atmosphere of Betelgeuse over multiple epochs at 0.7, 1.3, 2.0, 3.5, and 6.1 cm. The extended atmosphere deviates from circular symmetry at all wavelengths while at some epochs we find possible evidence for small pockets of gas significantly cooler than the mean global temperature. We find no evidence for the recently reported e-MERLIN radio hotspots in any of our multi-epoch VLA/PT data, despite having sufficient spatial resolution and sensitivity at short wavelengths, and conclude that these radio hotspots are most likely interferometric artefacts. The mean gas temperature of the extended atmosphere has a typical value of 3000 K at 2 $R_{\\star}$ and decreases to 1800 K at 6 $R_{\\star}$, in broad agreement with the findings of the single epoch study from Lim et al. (1998). The overall temperature profile of the extended atmosphere between $2 R_{\\star} \\less...

  1. Atmosphere-only GCM (ACCESS1.0) simulations with prescribed land surface temperatures

    Science.gov (United States)

    Ackerley, Duncan; Dommenget, Dietmar

    2016-06-01

    General circulation models (GCMs) are valuable tools for understanding how the global ocean-atmosphere-land surface system interacts and are routinely evaluated relative to observational data sets. Conversely, observational data sets can also be used to constrain GCMs in order to identify systematic errors in their simulated climates. One such example is to prescribe sea surface temperatures (SSTs) such that 70 % of the Earth's surface temperature field is observationally constrained (known as an Atmospheric Model Intercomparison Project, AMIP, simulation). Nevertheless, in such simulations, land surface temperatures are typically allowed to vary freely, and therefore any errors that develop over the land may affect the global circulation. In this study therefore, a method for prescribing the land surface temperatures within a GCM (the Australian Community Climate and Earth System Simulator, ACCESS) is presented. Simulations with this prescribed land surface temperature model produce a mean climate state that is comparable to a simulation with freely varying land temperatures; for example, the diurnal cycle of tropical convection is maintained. The model is then developed further to incorporate a selection of "proof of concept" sensitivity experiments where the land surface temperatures are changed globally and regionally. The resulting changes to the global circulation in these sensitivity experiments are found to be consistent with other idealized model experiments described in the wider scientific literature. Finally, a list of other potential applications is described at the end of the study to highlight the usefulness of such a model to the scientific community.

  2. Atmospheric point discharge current measurements using a temperature-compensated logarithmic current amplifier

    OpenAIRE

    Marlton, Graeme; Harrison, R. Giles; Nicoll, Keri A

    2013-01-01

    Measurements of atmospheric corona currents have been made for over 100 years to indicate the atmospheric electric field. Corona currents vary substantially, in polarity and in magnitude. The instrument described here uses a sharp point sensor connected to a temperature compensated bi-polar logarithmic current amplifier. Calibrations over a range of currents from ±10 fA to ±3 μA and across ±20 ◦C show it has an excellent logarithmic response over six orders of magnitude from 1 pA to 1 μA i...

  3. Atmospheric pressure chemical vapor deposition (APCVD) grown bi-layer graphene transistor characteristics at high temperature

    KAUST Repository

    Qaisi, Ramy M.

    2014-05-15

    We report the characteristics of atmospheric chemical vapor deposition grown bilayer graphene transistors fabricated on ultra-scaled (10 nm) high-κ dielectric aluminum oxide (Al2O3) at elevated temperatures. We observed that the drive current increased by >400% as temperature increased from room temperature to 250 °C. Low gate leakage was maintained for prolonged exposure at 100 °C but increased significantly at temperatures >200 °C. These results provide important insights for considering chemical vapor deposition graphene on aluminum oxide for high temperature applications where low power and high frequency operation are required. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Venus high temperature atmospheric dropsonde and extreme-environment seismometer (HADES)

    Science.gov (United States)

    Boll, Nathan J.; Salazar, Denise; Stelter, Christopher J.; Landis, Geoffrey A.; Colozza, Anthony J.

    2015-06-01

    The atmospheric composition and geologic structure of Venus have been identified by the US National Research Council's Decadal Survey for Planetary Science as priority targets for scientific exploration; however, the high temperature and pressure at the surface, along with the highly corrosive chemistry of the Venus atmosphere, present significant obstacles to spacecraft design that have severely limited past and proposed landed missions. Following the methodology of the NASA Innovative Advanced Concepts (NIAC) proposal regime and the Collaborative Modeling and Parametric Assessment of Space Systems (COMPASS) design protocol, this paper presents a conceptual study and initial feasibility analysis for a Discovery-class Venus lander capable of an extended-duration mission at ambient temperature and pressure, incorporating emerging technologies within the field of high temperature electronics in combination with novel configurations of proven, high Technology Readiness Level (TRL) systems. Radioisotope Thermal Power (RTG) systems and silicon carbide (SiC) communications and data handling are examined in detail, and various high-temperature instruments are proposed, including a seismometer and an advanced photodiode imager. The study combines this technological analysis with proposals for a descent instrument package and a relay orbiter to demonstrate the viability of an integrated atmospheric and in-situ geologic exploratory mission that differs from previous proposals by greatly reducing the mass, power requirements, and cost, while achieving important scientific goals.

  5. Venus High Temperature Atmospheric Dropsonde and Extreme-Environment Seismometer (HADES)

    Science.gov (United States)

    Boll, Nathan J.; Salazar, Denise; Stelter, Christopher J.; Landis, Geoffrey A.; Colozza, Anthony J.

    2014-01-01

    The atmospheric composition and geologic structure of Venus have been identified by the US National Research Council's Decadal Survey for Planetary Science as priority targets for scientific exploration, however the high temperature and pressure at the surface, along with the highly corrosive chemistry of the Venus atmosphere, present significant obstacles to spacecraft design that have severely limited past and proposed landed missions. Following the methodology of the NASA Innovative Advanced Concepts (NIAC) proposal regime and the Collaborative Modeling and Parametric Assessment of Space Systems (COMPASS) design protocol, this paper presents a conceptual study and initial feasibility analysis for a Discovery-class Venus lander capable of an extended-duration mission at ambient temperature and pressure, incorporating emerging technologies within the field of high temperature electronics in combination with novel configurations of proven, high Technology Readiness Level (TRL) systems. Radioisotope Thermal Power (RTG) systems and silicon carbide (SiC) communications and data handling are examined in detail, and various high-temperature instruments are proposed, including a seismometer and an advanced photodiode imager. The study combines this technological analysis with proposals for a descent instrument package and a relay orbiter to demonstrate the viability of an integrated atmospheric and in-situ geologic exploratory mission that differs from previous proposals by greatly reducing the mass, power requirements, and cost, while achieving important scientific goals.

  6. Morphological features and variations of temperature in the upper thermosphere simulated by a whole atmosphere GCM

    Directory of Open Access Journals (Sweden)

    H. Fujiwara

    2010-02-01

    Full Text Available In order to illustrate morphological features and variations of temperature in the upper thermosphere, we performed numerical simulations with a whole atmosphere general circulation model (GCM for the solar minimum and geomagnetically quiet conditions in March, June, September, and December. In previous GCMs, tidal effects were imposed at the lower boundaries assuming dominant diurnal and semi-diurnal tidal modes. Since the GCM used in the present study covers all the atmospheric regions, the atmospheric tides with various modes are generated within the GCM. The global temperature distributions obtained from the GCM are in agreement with ones obtained from NRLMSISE-00. In addition, the GCM also represents localised temperature structures which are superimposed on the global day-night distributions. These localised structures, which vary from hour to hour, would be observed as variations with periods of about 2–3 h at a single site. The amplitudes of the 2–3 h variations are significant at high-latitude, while the amplitudes are small at low-latitude. The diurnal temperature variation is more clearly identified at low-latitude than at high-latitude. When we assume the same high-latitude convection electric field in each month, the temperature calculated in the polar cap region shows diurnal variation more clearly in winter than in summer. The midnight temperature maximum (MTM, which is one of the typical low-latitude temperature structures, is also seen in the GCM results. The MTMs in the GCM results show significant day-to-day variation with amplitudes of several 10s to about 150 K. The wind convergence and stream of warm air are found around the MTM. The GCM also represent the meridional wind reversals and/or abatements which are caused due to local time variations of airflow pattern in the low-latitude region.

  7. Laser diagnostics on atmospheric-pressure low-temperature helium pulsed plasmas in room- and cryogenic-temperature environments

    Science.gov (United States)

    Sakakibara, Noritaka; Muneoka, Hitoshi; Urabe, Keiichiro; Yasui, Ryoma; Terashima, Kazuo

    2015-09-01

    In atmospheric-pressure low- temperature plasmas, the control of the plasma gas temperature (Tg) by a few kelvin is considered to be crucial for their applications to novel materials processing such as bio-materials. However, there have been only few studies that focused on the influence of Tg on the plasma characteristics. On the other hand, it was reported that helium metastables played a key role in the dependency of chemical reactions on Tg in helium-nitrogen plasmas. In this study, laser diagnostics were carried out in atmospheric-pressure helium pulsed plasmas near or below room temperature, at 340 -100 K. Parallel electrodes of copper rods (diameter: 2 mm) with a gap distance of 535 μm were used and pulsed discharges with a pulse width of a few hundred nanoseconds were generated inside a reactor. The density and lifetime of helium metastables were estimated by laser absorption spectroscopy measurements and Tg was evaluated by near-infrared laser heterodyne interferometry measurements. At 300 K, the helium metastable density was 1.5 × 1013 cm-3 while the lifetime was 3.1 μs, and increase in Tg was up to 70 K. Dependency of the density and lifetime of helium metastables on Tg was observed and also discussed.

  8. Corona discharge as a temperature probe of atmospheric air microwave plasma jet

    International Nuclear Information System (INIS)

    We developed and tested a new method for temperature measurements of near-LTE air plasmas at atmospheric pressure. This method is specifically suitable for plasmas at relatively low gas temperature (800-1700 K) with no appropriate radiation for direct spectroscopic temperature measurements. Corona discharge producing cold non-equilibrium plasma is employed as a source of excitation and is placed into the microwave plasma jet. The gas temperature of the microwave plasma jet is determined as the rotational temperature of N2* produced in the corona discharge. The corona probe temperature measurement was tested by the use of a thermocouple. We found a fairly good agreement between the two methods after correcting the thermocouple measured temperatures for radiative losses. The corona probe method can be generally applied to determine the temperature of the near-LTE plasmas and contrary to the thermocouple it can be used for higher plasma temperatures and is not affected by radiative losses and problems of interaction with the microwave plasma and electromagnetic fields.

  9. Atmospheric depression-mediated water temperature changes affect the vertical movement of chum salmon Oncorhynchus keta.

    Science.gov (United States)

    Kitagawa, Takashi; Hyodo, Susumu; Sato, Katsufumi

    2016-08-01

    The Sanriku coastal area, Japan, is one of the southern-most natural spawning regions of chum salmon Oncorhynchus keta. Here, we report their behavioral response to changes in ambient temperature after the passage of an atmospheric depression during the early spawning season. Before the passage, all electrically tagged fish moved vertically for several hours to depths below the shallow thermocline at >100 m. However, during the atmospheric depression, the salmon shortened the duration of their vertical movements and spent most time at the surface. The water column was homogenous at thermocline was no longer in a thermally defined layer, due to strong vertical mixing by high wave action. Instead, they likely spent time within the cooler water temperatures at the surface of bays to minimize metabolic energy cost during migration.

  10. Analytical design of sensors for measuring during terminal phase of atmospheric temperature planetary entry

    Science.gov (United States)

    Millard, J. P.; Green, M. J.; Sommer, S. C.

    1972-01-01

    An analytical study was conducted to develop a sensor for measuring the temperature of a planetary atmosphere from an entry vehicle traveling at supersonic speeds and having a detached shock. Such a sensor has been used in the Planetary Atmosphere Experiments Test Probe (PAET) mission and is planned for the Viking-Mars mission. The study specifically considered butt-welded thermocouple sensors stretched between two support posts; however, the factors considered are sufficiently general to apply to other sensors as well. This study included: (1) an investigation of the relation between sensor-measured temperature and free-stream conditions; (2) an evaluation of the effects of extraneous sources of heat; (3) the development of a computer program for evaluating sensor response during entry; and (4) a parametric study of sensor design characteristics.

  11. Dominant modes of Diurnal Temperature Range variability over Europe and their relationships with large-scale atmospheric circulation and sea surface temperature anomaly patterns

    OpenAIRE

    Ionita, Monica; Lohmann, Gerrit; Rimbu, Norel; Scholz, Patrick

    2012-01-01

    The relationships between the dominant modes of interannual variability of Diurnal Temperature Range (DTR) over Europe and large-scale atmospheric circulation and sea surface temperature anomaly fields are investigated through statistical analysis of observed and reanalysis data. It is shown that the dominant DTR modes as well as their relationship with large-scale atmospheric circulation and sea surface temperature anomaly fields are specific for each season. During winter the first and seco...

  12. Effect of temperature-dependent organic carbon decay on atmospheric pCO2

    Science.gov (United States)

    Matsumoto, Katsumi; Hashioka, Taketo; Yamanaka, Yasuhiro

    2007-06-01

    Extendingy an almost universal observation that the rate of microbial activity increases with temperature, we propose that marine microbial activity was suppressed during previous glacial periods and allowed proportionally more organic carbon to be exported out of the surface ocean. A stronger organic carbon pump and therefore lower rain ratios of CaCO3 to organic carbon may have contributed to the low atmospheric CO2 content during the Last Glacial Maximum. Previous study of temperature-dependent export production (Laws et al., 2000) and our map of data-based, global distribution of the rain ratios lend support to today's rain ratios being controlled at least partly by temperature. A close examination with a high-resolution regional ocean ecosystem model indicates that the correlation between rain ratio and temperature is caused indeed by preferential remineralization of organic matter, but a part of the correlation is also driven by temperature-dependent community composition. An extrapolation of these results to the globe using a global carbon cycle box model with a module for sediments indicates that the drawdown of atmospheric CO2 by the proposed mechanism is approximately 30 ppm. While this estimate is subject to uncertainty, the fact that it represents nearly one third of the glacial-interglacial variation in atmosphere pCO2 suggests the potential importance of the new mechanism. Given the historical difficulty in explaining the full CO2 amplitude with a single cause, we suggest that a set of multiple mechanisms were responsible and that the temperature-dependent POC degradation rate is one of them. We discuss two possible difficulties with our proposal that have to do with the potentially important role that ballasts play in organic carbon export and the possibility that enhanced biological pump is self limiting.

  13. Temperatures at the last interglacial simulated by a coupled ocean-atmosphere climate model

    OpenAIRE

    Montoya Redondo, María Luisa; Crowley, Thomas J.; von Storch, Hans

    1998-01-01

    The last interglacial (Eemian, 125,000 years ago) has generally been considered the warmest time period in the last 200,000 years and thus sometimes been used as a reference for greenhouse projections. Herein we report results from a coupled ocean-atmosphere climate model of the surface temperature response to changes in the radiative forcing at the last interglacial. Although the model generates the expected summer warming in the northern hemisphere, winter cooling of a comparable magnitude ...

  14. The measurement of the electron temperature in a spark discharge in air at atmospheric pressure

    International Nuclear Information System (INIS)

    The electron temperature in atmospheric pressure spark surface discharge was measured from the relative intensity ratio using several well-resolved atomic N I, N II, O II lines. The evaluated value is of 18 000 K. The repeated sparks were glowed by a pulsed high voltage source which restricted the are phase of sparks by appropriate low value of capacitors in voltage multiplier. (Authors)

  15. Comment on "Scaling of atmosphere and ocean temperature correlations in observations and climate models"

    CERN Document Server

    Bunde, A; Havlin, S; Koscielny-Bunde, E; Schellnhuber, H J; Vjushin, D; Bunde, Armin; Eichner, Jan F.; Havlin, Shlomo; Koscielny-Bunde, Eva; Schellnhuber, Hans J.; Vjushin, Dmitry

    2003-01-01

    In a recent letter [K. Fraedrich and R. Blender, Phys. Rev. Lett. 90, 108501 (2003)], Fraedrich and Blender studied the scaling of atmosphere and ocean temperature. They analyzed monthly temperature records by using the detrended fluctuation analysis and claim that the scaling exponent alpha over the inner continents is equal to 0.5, being characteristic of uncorrelated random sequences. Here we show that also for the inner continents, the exponent is between 0.6 and 0.7, similar as for the coastline-stations.

  16. Atmospheric pressure and temperature profiling using near IR differential absorption lidar

    Science.gov (United States)

    Korb, C. L.; Schwemmer, G. K.; Dombrowski, M.; Weng, C. Y.

    1983-01-01

    The present investigation is concerned with differential absorption lidar techniques for remotely measuring the atmospheric temperature and pressure profile, surface pressure, and cloud top pressure-height. The procedure used in determining the pressure is based on the conduction of high-resolution measurements of absorption in the wings of lines in the oxygen A band. Absorption with respect to these areas is highly pressure sensitive in connection with the mechanism of collisional line broadening. The method of temperature measurement utilizes a determination of the absorption at the center of a selected line in the oxygen A band which originates from a quantum state with high ground state energy.

  17. The relationship between ozone formation and air temperature in the atmospheric surface layer

    Science.gov (United States)

    Belan, Boris D.; Savkin, Denis; Tolmachev, Gennadii

    2016-04-01

    Studying the formation and dynamics of ozone in the atmosphere is important due to several reasons. First, the contribution of tropospheric ozone to the global greenhouse effect is only slightly less than that of water vapor, carbon dioxide, and methane. Second, tropospheric ozone acts as a strong poison that has negative effects on human health, animals, and vegetation. Third, being a potent oxidizer, ozone destroys almost all materials, including platinum group metals and compounds. Fourthly, ozone is formed in situ from precursors as a result of photochemical processes, but not emitted into the atmosphere by any industrial enterprises directly. In this work, we present some results of the study aimed at the revealing relationship between ozone formation rate and surface air temperature in the background atmosphere. It has been found that this relationship is nonlinear. Analysis of the possible reasons showed that the nonlinear character of this relationship may be due to a nonlinear increase in the reaction constants versus air temperature and a quadratic increase in the concentration of hydrocarbons with increasing temperature. This work was supported by the Ministry of Education and Science contract no.14.613.21.0013 (ID: RFMEFI61314X0013).

  18. [Effects of temperature and heating time on armco iron spectral emissivity in atmospheric environment].

    Science.gov (United States)

    Yu, Kun; Wang, Wen-Bao; Zhang, Kai-Hua; Liu, Yu-Fang

    2014-09-01

    The spectral emissivity of pure iron at 1.55 μm was investigated systematically by using our self-designed reflective experimental apparatus based on the Kirchhoff's law, and the influences of temperature and heating time on the spectral emissivity of pure iron were also discussed. The experimental data showed that the spectral emissivity of pure iron increased with temperature rising and its peak value and valley value appeared at certain temperatures. By analyzing the emissivity model of metal with oxidation layer, the variation of the spectral emissivity of pure iron was illustrated. The influence of heating time on the spectral emissivity was different at different temperature. The research results will further enrich pure iron spectral emissivity data, and provide the experimental basis for its application in atmospheric environment.

  19. A Software Tool for Atmospheric Correction and Surface Temperature Estimation of Landsat Infrared Thermal Data

    Directory of Open Access Journals (Sweden)

    Benjamin Tardy

    2016-08-01

    Full Text Available Land surface temperature (LST is an important variable involved in the Earth’s surface energy and water budgets and a key component in many aspects of environmental research. The Landsat program, jointly carried out by NASA and the USGS, has been recording thermal infrared data for the past 40 years. Nevertheless, LST data products for Landsat remain unavailable. The atmospheric correction (AC method commonly used for mono-window Landsat thermal data requires detailed information concerning the vertical structure (temperature, pressure and the composition (water vapor, ozone of the atmosphere. For a given coordinate, this information is generally obtained through either radio-sounding or atmospheric model simulations and is passed to the radiative transfer model (RTM to estimate the local atmospheric correction parameters. Although this approach yields accurate LST data, results are relevant only near this given coordinate. To meet the scientific community’s demand for high-resolution LST maps, we developed a new software tool dedicated to processing Landsat thermal data. The proposed tool improves on the commonly-used AC algorithm by incorporating spatial variations occurring in the Earth’s atmosphere composition. The ERA-Interim dataset (ECMWFmeteorological organization was used to retrieve vertical atmospheric conditions, which are available at a global scale with a resolution of 0.125 degrees and a temporal resolution of 6 h. A temporal and spatial linear interpolation of meteorological variables was performed to match the acquisition dates and coordinates of the Landsat images. The atmospheric correction parameters were then estimated on the basis of this reconstructed atmospheric grid using the commercial RTMsoftware MODTRAN. The needed surface emissivity was derived from the common vegetation index NDVI, obtained from the red and near-infrared (NIR bands of the same Landsat image. This permitted an estimation of LST for the entire

  20. Interannual variability of the atmospheric CO2 growth rate: roles of precipitation and temperature

    Science.gov (United States)

    Wang, Jun; Zeng, Ning; Wang, Meirong

    2016-04-01

    The interannual variability (IAV) in atmospheric CO2 growth rate (CGR) is closely connected with the El Niño-Southern Oscillation. However, sensitivities of CGR to temperature and precipitation remain largely uncertain. This paper analyzed the relationship between Mauna Loa CGR and tropical land climatic elements. We find that Mauna Loa CGR lags precipitation by 4 months with a correlation coefficient of -0.63, leads temperature by 1 month (0.77), and correlates with soil moisture (-0.65) with zero lag. Additionally, precipitation and temperature are highly correlated (-0.66), with precipitation leading by 4-5 months. Regression analysis shows that sensitivities of Mauna Loa CGR to temperature and precipitation are 2.92 ± 0.20 PgC yr-1 K-1 and -0.46 ± 0.07 PgC yr-1 100 mm-1, respectively. Unlike some recent suggestions, these empirical relationships favor neither temperature nor precipitation as the dominant factor of CGR IAV. We further analyzed seven terrestrial carbon cycle models, from the TRENDY project, to study the processes underlying CGR IAV. All models capture well the IAV of tropical land-atmosphere carbon flux (CFTA). Sensitivities of the ensemble mean CFTA to temperature and precipitation are 3.18 ± 0.11 PgC yr-1 K-1 and -0.67 ± 0.04 PgC yr-1 100 mm-1, close to Mauna Loa CGR. Importantly, the models consistently show the variability in net primary productivity (NPP) dominates CGR, rather than heterotrophic respiration. Because previous studies have proved that NPP is largely driven by precipitation in tropics, it suggests a key role of precipitation in CGR IAV despite the higher CGR correlation with temperature. Understanding the relative contribution of CO2 sensitivity to precipitation and temperature has important implications for future carbon-climate feedback using such ''emergent constraint''.

  1. Implications of solar irradiance variability upon long-term changes in the Earth's atmospheric temperatures

    Science.gov (United States)

    Lee, Robert B., III

    1992-01-01

    From 1979 through 1987, it is believed that variability in the incoming solar energy played a significant role in changing the Earth's climate. Using high-precision spacecraft radiometric measurements, the incoming total solar irradiance (total amount of solar power per unit area) and the Earth's mean, global atmospheric temperatures were found to vary in phase with each other. The observed irradiance and temperature changes appeared to be correlated with the 11-year cycle of solar magnetic activity. During the period from 1979 through 1985, both the irradiance and temperature decreased. From 1985 to 1987, they increased. The irradiance changed approximately 0.1 percent, while the temperature varied as much as 0.6 C. During the 1979-1987 period, the temperatures were forecasted to rise linearly because of the anthropogenic build-up of carbon dioxide and the hypothesized 'global warming', 'greenhouse effect', scenarios. Contrary to these scenarios, the temperatures were found to vary in a periodic manner in phase with the solar irradiance changes. The observed correlations between irradiance and temperature variabilily suggest that the mean, global temperature of the Earth may decline between 1990 and 1997 as solar magnetic activity decreases.

  2. On the average temperature of airless spherical bodies and the magnitude of Earth’s atmospheric thermal effect

    OpenAIRE

    Volokin, Den; ReLlez, Lark

    2014-01-01

    The presence of atmosphere can appreciably warm a planet’s surface above the temperature of an airless environment. Known as a natural Greenhouse Effect (GE), this near-surface Atmospheric Thermal Enhancement (ATE) as named herein is presently entirely attributed to the absorption of up-welling long-wave radiation by greenhouse gases. Often quoted as 33 K for Earth, GE is estimated as a difference between planet’s observed mean surface temperature and an effective radiating temperature calcul...

  3. Investigating Titan's Atmospheric Chemistry at Low Temperature in Support of the NASA Cassini Mission

    Science.gov (United States)

    Sciamma-O'Brien, Ella; Salama, Farid

    2013-01-01

    Titan's atmosphere, composed mainly of N2 and CH4, is the siege of a complex chemistry induced by solar UV radiation and electron bombardment from Saturn's magnetosphere. This organic chemistry occurs at temperatures lower than 200 K and leads to the production of heavy molecules and subsequently solid aerosols that form the orange haze surrounding Titan. The Titan Haze Simulation (THS) experiment has been developed on the COSMIC simulation chamber at NASA Ames in order to study the different steps of Titan's atmospheric chemistry at low temperature and to provide laboratory data in support for Cassini data analysis. The chemistry is simulated by plasma in the stream of a supersonic expansion. With this unique design, the gas mixture is adiabatically cooled to Titan-like temperature (approx. 150 K) before inducing the chemistry by plasma discharge. Different gas mixtures containing N2, CH4, and the first products of the N2,-CH4 chemistry (C2H2, C2H4, C6H6...) but also heavier molecules such as PAHs or nitrogen containing PAHs can be injected. Both the gas phase and solid phase products resulting from the plasma-induced chemistry can be monitored and analyzed. Here we present the results of recent gas phase and solid phase studies that highlight the chemical growth evolution when injecting heavier hydrocarbon trace elements in the initial N2-CH4 mixture. Due to the short residence time of the gas in the plasma discharge, only the first steps of the chemistry have time to occur in a N2-CH4 discharge. However by adding acetylene and benzene to the initial N2-CH4 mixture, we can study the intermediate steps of Titan's atmospheric chemistry as well as specific chemical pathways. These results show the uniqueness of the THS experiment to help understand the first and intermediate steps of Titan fs atmospheric chemistry as well as specific chemical pathways leading to Titan fs haze formation.

  4. Atmospheric controls on northeast Pacific temperature variability and change, 1900-2012.

    Science.gov (United States)

    Johnstone, James A; Mantua, Nathan J

    2014-10-01

    Over the last century, northeast Pacific coastal sea surface temperatures (SSTs) and land-based surface air temperatures (SATs) display multidecadal variations associated with the Pacific Decadal Oscillation, in addition to a warming trend of ∼ 0.5-1 °C. Using independent records of sea-level pressure (SLP), SST, and SAT, this study investigates northeast (NE) Pacific coupled atmosphere-ocean variability from 1900 to 2012, with emphasis on the coastal areas around North America. We use a linear stochastic time series model to show that the SST evolution around the NE Pacific coast can be explained by a combination of regional atmospheric forcing and ocean persistence, accounting for 63% of nonseasonal monthly SST variance (r = 0.79) and 73% of variance in annual means (r = 0.86). We show that SLP reductions and related atmospheric forcing led to century-long warming around the NE Pacific margins, with the strongest trends observed from 1910-1920 to 1940. NE Pacific circulation changes are estimated to account for more than 80% of the 1900-2012 linear warming in coastal NE Pacific SST and US Pacific northwest (Washington, Oregon, and northern California) SAT. An ensemble of climate model simulations run under the same historical radiative forcings fails to reproduce the observed regional circulation trends. These results suggest that natural internally generated changes in atmospheric circulation were the primary cause of coastal NE Pacific warming from 1900 to 2012 and demonstrate more generally that regional mechanisms of interannual and multidecadal temperature variability can also extend to century time scales.

  5. Attribution of atmospheric CO2 and temperature increases to regions: importance of preindustrial land use change

    International Nuclear Information System (INIS)

    The historical contribution of each country to today’s observed atmospheric CO2 excess and higher temperatures has become a basis for discussions around burden-sharing of greenhouse gas reduction commitments in political negotiations. However, the accounting methods have considered greenhouse gas emissions only during the industrial era, neglecting the fact that land use changes (LUC) have caused emissions long before the Industrial Revolution. Here, we hypothesize that considering preindustrial LUC affects the attribution because the geographic pattern of preindustrial LUC emissions differs significantly from that of industrial-era emissions and because preindustrial emissions have legacy effects on today’s atmospheric CO2 concentrations and temperatures. We test this hypothesis by estimating CO2 and temperature increases based on carbon cycle simulations of the last millennium. We find that accounting for preindustrial LUC emissions results in a shift of attribution of global temperature increase from the industrialized countries to less industrialized countries, in particular South Asia and China, by up to 2–3%, a level that may be relevant for political discussions. While further studies are needed to span the range of plausible quantifications, our study demonstrates the importance of including preindustrial emissions for the most scientifically defensible attribution. (letter)

  6. Direct measurements of the effect of biomass burning over the Amazon on the atmospheric temperature profile

    Directory of Open Access Journals (Sweden)

    L. Remer

    2009-11-01

    Full Text Available Aerosols suspended in the atmosphere interact with solar radiation and clouds, thus change the radiation energy fluxes in the atmospheric column. In this paper we measure changes in the atmospheric temperature profile as a function of the smoke loading and the cloudiness, over the Amazon basin, during the dry seasons (August and September of 2005–2008. We show that as the aerosol optical depth (AOD increases from 0.02 to a value of ~0.6, there is a decrease of ~4°C at 1000 hPa, and an increase of ~1.5°C at 850 hPa. The warming of the aerosol layer at 850 hPa is likely due to aerosol absorption when the particles are exposed to direct illumination by the sun. The large values of cooling in the lower layers could be explained by a combination of aerosol extinction of the solar flux in the layers aloft together with an aerosol-induced increase of cloud cover which shade the lower atmosphere. We estimate that the increase in cloud fraction due to aerosol contributes about half of the observed cooling in the lower layers.

  7. The relation between atmospheric humidity and temperature trends for stratospheric water

    Science.gov (United States)

    Fueglistaler, S.; Liu, Y. S.; Flannaghan, T. J.; Haynes, P. H.; Dee, D. P.; Read, W. J.; Remsberg, E. E.; Thomason, L. W.; Hurst, D. F.; Lanzante, J. R.; Bernath, P. F.

    2013-01-01

    We analyze the relation between atmospheric temperature and water vapor—a fundamental component of the global climate system—for stratospheric water vapor (SWV). We compare measurements of SWV (and methane where available) over the period 1980-2011 from NOAA balloon-borne frostpoint hygrometer (NOAA-FPH), SAGE II, Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS)/Aura, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) to model predictions based on troposphere-to-stratosphere transport from ERA-Interim, and temperatures from ERA-Interim, Modern Era Retrospective-Analysis (MERRA), Climate Forecast System Reanalysis (CFSR), Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC), HadAT2, and RICHv1.5. All model predictions are dry biased. The interannual anomalies of the model predictions show periods of fairly regular oscillations, alternating with more quiescent periods and a few large-amplitude oscillations. They all agree well (correlation coefficients 0.9 and larger) with observations for higher-frequency variations (periods up to 2-3 years). Differences between SWV observations, and temperature data, respectively, render analysis of the model minus observation residual difficult. However, we find fairly well-defined periods of drifts in the residuals. For the 1980s, model predictions differ most, and only the calculation with ERA-Interim temperatures is roughly within observational uncertainties. All model predictions show a drying relative to HALOE in the 1990s, followed by a moistening in the early 2000s. Drifts to NOAA-FPH are similar (but stronger), whereas no drift is present against SAGE II. As a result, the model calculations have a less pronounced drop in SWV in 2000 than HALOE. From the mid-2000s onward, models and observations agree reasonably, and some differences can be traced to problems in the temperature data. These results indicate that both SWV and temperature data may still

  8. The Relation Between Atmospheric Humidity and Temperature Trends for Stratospheric Water

    Science.gov (United States)

    Fueglistaler, S.; Liu, Y. S.; Flannaghan, T. J.; Haynes, P. H.; Dee, D. P.; Read, W. J.; Remsberg, E. E.; Thomason, L. W.; Hurst, D. F.; Lanzante, J. R.; Bernath, P. F.

    2013-01-01

    We analyze the relation between atmospheric temperature and water vapor-a fundamental component of the global climate system-for stratospheric water vapor (SWV). We compare measurements of SWV (and methane where available) over the period 1980-2011 from NOAA balloon-borne frostpoint hygrometer (NOAA-FPH), SAGE II, Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS)/Aura, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) to model predictions based on troposphere-to-stratosphere transport from ERA-Interim, and temperatures from ERA-Interim, Modern Era Retrospective-Analysis (MERRA), Climate Forecast System Reanalysis (CFSR), Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC), HadAT2, and RICHv1.5. All model predictions are dry biased. The interannual anomalies of the model predictions show periods of fairly regular oscillations, alternating with more quiescent periods and a few large-amplitude oscillations. They all agree well (correlation coefficients 0.9 and larger) with observations for higherfrequency variations (periods up to 2-3 years). Differences between SWV observations, and temperature data, respectively, render analysis of the model minus observation residual difficult. However, we find fairly well-defined periods of drifts in the residuals. For the 1980s, model predictions differ most, and only the calculation with ERA-Interim temperatures is roughly within observational uncertainties. All model predictions show a drying relative to HALOE in the 1990s, followed by a moistening in the early 2000s. Drifts to NOAA-FPH are similar (but stronger), whereas no drift is present against SAGE II. As a result, the model calculations have a less pronounced drop in SWV in 2000 than HALOE. From the mid-2000s onward, models and observations agree reasonably, and some differences can be traced to problems in the temperature data. These results indicate that both SWV and temperature data may still suffer

  9. Convective organization in the super-parameterized community atmosphere model with constant surface temperature

    Science.gov (United States)

    Kuang, Z.

    2015-12-01

    Organization in a moist convecting atmosphere is investigated using the super-parameterized community atmosphere model (SPCAM) in aquaplanet setting with constant surface temperature, with and without planetary rotation. Without radiative and surface feedbacks, convective organization is dominated by convectively coupled gravity waves without planetary rotation and convectively coupled equatorial waves when there is planetary rotation. This behavior is well captured when the cloud resolving model (CRM) in SPCAM is replaced by its linear response function, computed following Kuang (2010), for the state of radiative convective equilibrium (RCE). With radiative feedback, however, convection self-aggregates, and with planetary rotation, the tropical zonal wavenumber-frequency spectrum features a red noise background. These behaviors in the presence of the radiative feedback are not captured when the CRM is replaced by its linear response function around the RCE state with radiative feedback included in the construction. Implications to organization in a moist convecting atmosphere will be discussed. Kuang, Z., Linear response functions of a cumulus ensemble to temperature and moisture perturbations and implication to the dynamics of convectively coupled waves, J. Atmos. Sci., 67, 941-962, (2010)

  10. Temperature-dependent Henry's law constants of atmospheric organics of biogenic origin.

    Science.gov (United States)

    Leng, Chunbo; Kish, J Duncan; Kelley, Judas; Mach, Mindy; Hiltner, Joseph; Zhang, Yunhong; Liu, Yong

    2013-10-10

    There have been growing interests in modeling studies to understand oxidation of volatile organic compounds in the gas phase and their mass transfer to the aqueous phase for their potential roles in cloud chemistry, formation of secondary organic aerosols, and fate of atmospheric organics. Temperature-dependent Henry's law constants, key parameters in the atmospheric models to account for mass transfer, are often unavailable. In the present work, we investigated gas-liquid equilibriums of isoprene, limonene, α-pinene, and linalool using a bubble column technique. These compounds, originating from biogenic sources, were selected for their implications in atmospheric cloud chemistry and secondary organic aerosol formation. We reported Henry's law constants (K(H)), first order loss rates (k), and gas phase diffusion coefficients over a range of temperatures relevant to the lower atmosphere (278-298 K) for the first time. The measurement results of K(H) values for isoprene, limonene, α-pinene, and linalool at 298 K were 0.036 ± 0.003; 0.048 ± 0.004; 0.029 ± 0.004; and 21.20 ± 0.30 mol L(-1) atm(-1), respectively. The fraction for these compounds in stratocumulus and cumulonimbus clouds at 278 K were also estimated in this work (isoprene, 1.0 × 10(-6), 6.8 × 10(-6); limonene, 1.5 × 10(-6), 1.0 × 10(-5); α-pinene, 4.5 × 10(-7), 3.1 × 10(-6); and linalool, 6.2 × 10(-4), 4.2 × 10(-3)). Our measurements in combination with literature results indicated that noncyclic alkenes could have smaller K(H) values than those of cyclic terpenes and that K(H) values may increase with an increasing number of double bonds. It was also shown that estimated Henry's law constants and their temperature dependence based on model prediction can differ from experimental results considerably and that direct measurements of temperature-dependent Henry's law constants of atmospheric organics are necessary for future work.

  11. Mars Global Surveyor Thermal Emission Spectrometer (TES) Observations: Atmospheric Temperatures During Aerobraking and Science Phasing

    Science.gov (United States)

    Conrath, Barney J.; Pearl, John C.; Smith, Michael D.; Maguire, William C.; Christensen, Philip R.; Dason, Shymala; Kaelberer, Monte S.

    1999-01-01

    Between September 1997, when the Mars Global Surveyor spacecraft arrived at Mars, and September 1998 when the final aerobraking phase of the mission began, the Thermal Emission Spectrometer (TES) has acquired an extensive data set spanning approximately half of a Martian year. Nadir-viewing spectral measurements from this data set within the 15-micrometers CO2 absorption band are inverted to obtain atmospheric temperature profiles from the surface up to about the 0.1 mbar level. The computational procedure used to retrieve the temperatures is presented. Mean meridional cross sections of thermal structure are calculated for periods of time near northern hemisphere fall equinox, winter solstice, and spring equinox, as well as for a time interval immediately following the onset of the Noachis Terra dust storm. Gradient thermal wind cross sections are calculated from the thermal structure. Regions of possible wave activity are identified using cross sections of rms temperature deviations from the mean. Results from both near-equinox periods show some hemispheric asymmetry with peak eastward thermal winds in the north about twice the magnitude of those in the south. The results near solstice show an intense circumpolar vortex at high northern latitudes and waves associated with the vortex jet core. Warming of the atmosphere aloft at mid-northern latitudes suggests the presence of a strong cross-equatorial Hadley circulation. Although the Noachis dust storm did not become global in scale, strong perturbations to the atmospheric structure are found, including an enhanced temperature maximum aloft at high northern latitudes resulting from intensification of the Hadley circulation. TES results for the various seasonal conditions are compared with published results from Mars general circulation models, and generally good qualitative agreement is found.

  12. Torrefaction and low temperature carbonization of oil palm fiber and Eucalyptus in nitrogen and air atmospheres.

    Science.gov (United States)

    Lu, Ke-Miao; Lee, Wen-Jhy; Chen, Wei-Hsin; Liu, Shih-Hsien; Lin, Ta-Chang

    2012-11-01

    Torrefaction is a pretreatment method for upgrading biomass as solid fuels. To provide flexible operations for effectively upgrading biomass at lower costs, the aim of this study was to investigate the properties of oil palm fiber and eucalyptus pretreated in nitrogen and air atmospheres at temperatures of 250-350°C for 1h. Based on energy and solid yield and introducing an energy-mass co-benefit index (EMCI), oil palm fiber pretreatment under nitrogen at 300°C provided the solid fuel with higher energy density and less volume compared to other temperatures. Pretreatment of oil palm fiber in air resulted in the fuel with low solid and energy yields and is therefore not recommended. For eucalyptus, nitrogen and air can be employed to upgrade the biomass, and the suggested temperatures are 325 and 275°C, respectively.

  13. An analysis of the dependence of clear-sky top-of-atmosphere outgoing longwave radiation on atmospheric temperature and water vapor

    Science.gov (United States)

    Dessler, A. E.; Yang, P.; Lee, J.; Solbrig, J.; Zhang, Z.; Minschwaner, K.

    2008-09-01

    We have analyzed observations of clear-sky top-of-atmosphere outgoing longwave radiation (OLR) measured by the Clouds and the Earth's Radiant Energy System (CERES). These measurements were obtained during March 2005 at night and over the ocean and cover latitudes from 70°N to 70°S. First, we compare the OLR measurements to OLR calculated from two radiative transfer models. The models use as input simultaneous and collocated measurements of atmospheric temperature and atmospheric water vapor made by the Atmospheric Infrared Sounder (AIRS). We find excellent agreement between the models' predictions of OLR and observations, well within the uncertainty of the measurements. We also analyze the sensitivity of OLR to changing surface temperature Ts, atmospheric temperature Ta, and atmospheric water vapor q. We find that OLR is most sensitive to unit changes in Ta when that change occurs in the lower troposphere. For q, the altitude distribution of sensitivity varies between the midlatitudes, subtropics, and the convective region. We also partition the observed variations in OLR into contributions from changing Ts, Ta, and q. In the midlatitudes, changes in Ts and Ta contribute approximately equally, and are partially offset by changes in q. In the subtropics, changes in Ta dominate, with a smaller contribution from changes in Ts and a relatively small offsetting contribution from q. In the tropical convective region, a rapid increase in q in the midtroposphere leads to a dramatic reduction in OLR with increasing Ts, which has been termed the "super greenhouse effect".

  14. The generalization of upper atmospheric wind and temperature based on the Voigt line shape profile.

    Science.gov (United States)

    Zhang, Chunmin; He, Jian

    2006-12-25

    The principle of probing the upper atmospheric wind field, which is the Voigt profile spectral line shape, is presented for the first time. By the Fourier Transform of Voigt profile, with the Imaging Spectroscope and the Doppler effect of electromagnetic wave, the distribution and calculation formulae of the velocity field, temperature field, and pressure field of the upper atmosphere wind field are given. The probed source is the two major aurora emission lines originated from the metastable O(1S) and O(1D) at 557.7nm and 630.0nm. From computer simulation and error analysis, the Voigt profile, which is the correlation of the Gaussian profile and Lorentzian profile, is closest to the actual airglow emission lines. PMID:19532147

  15. Radial Temperature Profile Measurements in a Microwave Plasma at Atmospheric Pressure

    Science.gov (United States)

    Green, K. M.; Borras, M. C.; Flores, G. J., III; Woskov, P. P.; Hadidi, K.; Thomas, P.

    1998-11-01

    Radial profile measurements of the electronic excitation and rotational temperature are obtained for a Microwave Plasma Continuous Emissions Monitor (MP-CEM). The MP-CEM, employed in monitoring trace metals in furnace exhausts using atomic emission spectroscopy, operates at atmospheric pressure with air as the working gas. An iron solution is introduced into the plasma, and the intensity of the atomic emission spectrum of the Fe I excited levels is measured. The relative intensities of these lines give the electronic excitation temperature. Rotational temperatures are obtained through molecular emission spectroscopy in nitrogen plasmas. To collect the profile measurements, an optical detection system equipped with a collimator lens scans the plasma. By applying Abel inversion techniques to the integrated signals from the scanned plasma chords, the radial temperature profile is determined. For a plasma maintained at 1.5 kW by a 2.45 GHz microwave source with an axial flow of 10 scfh and a swirl flow of 20 scfh, a core electronic excitation temperature in air of 5300 K ± 600 K is measured, and a rotational temperature in nitrogen of 5100 K ± 300 K has been determined.

  16. Rapid coupling of Antarctic temperature and atmospheric CO2 during deglaciation

    Directory of Open Access Journals (Sweden)

    T. D. van Ommen

    2012-02-01

    Full Text Available Antarctic ice cores provide clear evidence of a close coupling between variations in Antarctic temperature and the atmospheric concentration of CO2 during the glacial/interglacial cycles of the past 800 thousand years. Precise information on the relative timing of the temperature and CO2 changes can assist in refining our understanding of the physical processes involved in this coupling. Here, we focus on the last deglaciation, 19 000 to 11 000 years before present, during which CO2 concentrations increased by ~80 parts per million by volume and Antarctic temperature increased by ~10 °C. Utilising a recently developed proxy for regional Antarctic temperature, derived from five near-coastal ice cores, and two ice core CO2 records with high dating precision, we show that the increase in CO2 lagged the increase in regional Antarctic temperature by only 0–400 years. This new value for the lag, consistent for both CO2 records, implies a faster feedback between temperature and CO2 than the centennial to millennial-scale lags suggested by previous studies.

  17. Behaviour of ferritic stainless steels subjected to dry biogas atmospheres at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Promdirek, P. [SIMaP, Grenoble INP/CNRS/UJF, BP 75, 38402 Saint Martin d' Heres cedex (France); Materials and Production Technology Engineering, King Mongkut' s University of Technology North Bangkok, 1518 Pibulsongkram road, Bangsue, Bangkok, 10800 (Thailand); Department of Metallurgical Engineering, Chulalongkorn University, 254 Phyathai Road, Patumwan, Bangkok, 10330 (Thailand); Lothongkhum, G. [Department of Metallurgical Engineering, Chulalongkorn University, 254 Phyathai Road, Patumwan, Bangkok, 10330 (Thailand); Chandra-ambhorn, S. [Materials and Production Technology Engineering, King Mongkut' s University of Technology North Bangkok, 1518 Pibulsongkram road, Bangsue, Bangkok, 10800 (Thailand); Wouters, Y.; Galerie, A. [SIMaP, Grenoble INP/CNRS/UJF, BP 75, 38402 Saint Martin d' Heres cedex (France)

    2011-07-15

    The objective of this study is to understand the high temperature corrosion behaviour of the ferritic stainless steel type AISI 441 (18CrTiNb), a candidate for SOFC interconnectors, under dry synthetic fermentation biogas (CH{sub 4} + CO{sub 2} mixtures), possibly used at the anode side of the cell. Thermodynamic analysis showed that, in such mixtures, the partial pressure of oxygen lies in the range of 10{sup -23} to 10{sup -20} bar for temperature between 700 and 900 C and that the formation of solid carbon may take place in several conditions. XRD results confirmed the formation of Cr{sub 2}O{sub 3} and Mn-Cr spinel, with a mixture of internal carbides. In this temperature range, kinetic experiments showed linear mass change. Comparing with the linear rate constants of 441 oxidised in pure CO{sub 2}, corrosion in biogas was larger and increased with increasing the methane content in the biogas. The surface morphology of the corroded specimens showed a dense oxide scale at temperatures less than 800 C, serving as an efficient barrier to carbon penetration. However, when the temperature reaches 900 C, cracks and pores appear in the oxide scale, carbon can precipitate and diffuse easier than at 800 C and may lead to internal carbide formation. In such biogas atmospheres, 800 C seems the maximum operating temperature of devices containing this ferritic stainless steel. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Influence of a Carrington-like event on the atmospheric chemistry, temperature and dynamics: revised

    International Nuclear Information System (INIS)

    This study investigates the influence of a major solar proton event (SPE) similar to the Carrington event of 1–2 September 1859 by means of the 3D chemistry climate model (CCM) SOCOL v2.0. Ionization rates were parameterized according to CRAC:CRII (Cosmic Ray-induced Atmospheric Cascade: Application for Cosmic Ray Induced Ionization), a detailed state-of-the-art model describing the effects of SPEs in the entire altitude range of the CCM from 0 to 80 km. This is the first study of the atmospheric effect of such an extreme event that considers all the effects of energetic particles, including the variability of galactic cosmic rays, in the entire atmosphere. We assumed two scenarios for the event, namely with a hard (as for the SPE of February 1956) and soft (as for the SPE of August 1972) spectrum of solar particles. We have placed such an event in the year 2020 in order to analyze the impact on a near future atmosphere. We find statistically significant effects on NOx, HOx, ozone, temperature and zonal wind. The results show an increase of NOx of up to 80 ppb in the northern polar region and an increase of up to 70 ppb in the southern polar region. HOx shows an increase of up to 4000%. Due to the NOx and HOx enhancements, ozone reduces by up to 60% in the mesosphere and by up to 20% in the stratosphere for several weeks after the event started. Total ozone shows a decrease of more than 20 DU in the northern hemisphere and up to 20 DU in the southern hemisphere. The model also identifies SPE induced statistically significant changes in the surface air temperature, with warming in the eastern part of Europe and Russia of up to 7 K for January. (letter)

  19. Climate-Induced Variability of Sea Level in Stockholm: Influence of Air Temperature and Atmospheric Circulation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This study is focused on climate-induced variation of sea level in Stockholm during 1873-1995. After the effect of the land uplift is removed, the residual is characterized and related to large-scale temperature and atmospheric circulation. The residual shows an overall upward trend, although this result depends on the uplift rate used. However, the seasonal distribution of the trend is uneven. There are even two months (June and August) that show a negative trend. The significant trend in August may be linked to fresh water input that is controlled by precipitation. The influence of the atmospheric conditions on the sea level is mainly manifested through zonal winds, vorticity and temperature. While the wind is important in the period January-May, the vorticity plays a main role during June and December. A successful linear multiple-regression model linking the climatic variables (zonal winds, vorticity and mean air temperature during the previous two months) and the sea level is established for each month. An independent verification of the model shows that it has considerable skill in simulating the variability.

  20. Influence of a Carrington-like event on the atmospheric chemistry, temperature and dynamics

    Directory of Open Access Journals (Sweden)

    M. Calisto

    2012-09-01

    Full Text Available We have modeled the atmospheric impact of a major solar energetic particle event similar in intensity to what is thought of the Carrington Event of 1–2 September 1859. Ionization rates for the August 1972 solar proton event, which had an energy spectrum comparable to the Carrington Event, were scaled up in proportion to the fluence estimated for both events. We have assumed such an event to take place in the year 2020 in order to investigate the impact on the modern, near future atmosphere. Effects on atmospheric chemistry, temperature and dynamics were investigated using the 3-D Chemistry Climate Model SOCOL v2.0. We find significant responses of NOx, HOx, ozone, temperature and zonal wind. Ozone and NOx have in common an unusually strong and long-lived response to this solar proton event. The model suggests a 3-fold increase of NOx generated in the upper stratosphere lasting until the end of November, and an up to 10-fold increase in upper mesospheric HOx. Due to the NOx and HOx enhancements, ozone reduces by up to 60–80% in the mesosphere during the days after the event, and by up to 20–40% in the middle stratosphere lasting for several months after the event. Total ozone is reduced by up to 20 DU in the Northern Hemisphere and up to 10 DU in the Southern Hemisphere. Free tropospheric and surface air temperatures show a significant cooling of more than 3 K and zonal winds change significantly by 3–5 m s−1 in the UTLS region. In conclusion, a solar proton event, if it took place in the near future with an intensity similar to that ascribed to of the Carrington Event of 1859, must be expected to have a major impact on atmospheric composition throughout the middle atmosphere, resulting in significant and persistent decrease in total ozone.

  1. Influence of a Carrington-like event on the atmospheric chemistry, temperature and dynamics

    Directory of Open Access Journals (Sweden)

    M. Calisto

    2012-06-01

    Full Text Available We have modeled the atmospheric impact of a major solar energetic particle event similar in intensity to what is thought of the Carrington Event of 1–2 September 1859. Ionization rates for the August 1972 solar proton event, which had an energy spectrum comparable to the Carrington Event, were scaled up in proportion to the fluence estimated for both events. We have assumed such an event to take place in the year 2020 in order to investigate the impact on the modern, near future atmosphere. Effects on atmospheric chemistry, temperature and dynamics were investigated using the 3-D Chemistry Climate Model SOCOL v2.0. We find significant responses of NOx, HOx, ozone, temperature and zonal wind. Ozone and NOx have in common an unusually strong and long-lived response to this solar proton event. The model suggests a 3-fold increase of NOx generated in the upper stratosphere lasting until the end of November, and an up to 10-fold increase in upper mesospheric HOx. Due to the NOx and HOx enhancements, ozone reduces by up to 60–80% in the mesosphere during the days after the event, and by up to 20–40% in the middle stratosphere lasting for several months after the event. Total ozone is reduced by up to 20 DU in the Northern Hemisphere and up to 10 DU in the Southern Hemisphere. Free tropospheric and surface air temperatures show a significant cooling of more than 3 K and zonal winds change significantly by 3–5 m s−1 in the UTLS region. In conclusion, a solar proton event, if it took place in the near future with an intensity similar to that ascribed to of the Carrington Event of 1859, must be expected to have a major impact on atmospheric composition throughout the middle atmosphere, resulting in significant and persistent decrease in total ozone.

  2. Limitations When Using Proxies of Atmospheric Circulation to Infer Regional Temperature

    Science.gov (United States)

    Kelsey, E. P.; Wake, C. P.; Osterberg, E. C.; Kreutz, K. J.

    2011-12-01

    One objective of ice core paleoclimatology is to reconstruct past variability of climate parameters such as surface air temperature. Stable isotope ratios of ice cores collected from some locations can be used with confidence to reconstruct regional air temperature. Other glaciochemical records (e.g., major ions) have been used as proxies for regional atmospheric circulation patterns, including the Arctic Oscillation and Pacific-North American pattern, typically based on the strength of semi-permanent sea level pressure centers such as the Icelandic Low and Aleutian Low. The Arctic Oscillation and Pacific North American pattern are associated with regional air temperature anomalies, and consequently ice core proxies of these circulation patterns could be used to infer paleotemperature patterns. However, detailed analysis of the 20th Century Reanalysis dataset (1871-2008) for the Northern Hemisphere winter suggests that these atmospheric circulation patterns do not always result in the same regional air temperature anomalies. A principal component analysis of detrended and area-weighted winter (December-March) temperature and sea level pressure was performed, and the leading eigenmodes were compared, along with the winter mean positions of the Icelandic and Aleutian Lows. Robust results based on multiple statistical analyses were obtained only when the extreme seasonal values of these variables were examined. Although statistically significant results were obtained when looking at temperature patterns associated with specific sea level pressure patterns and the positions of the Icelandic and Aleutian Lows, more consistent relationships were found when examining sea level pressure patterns associated with the leading eigenmodes of temperature. The seasons of extreme eigenvalues of the leading temperature eigenmodes are associated with mean positions of the Icelandic and Aleutian Lows at climatologically extreme north/south and west/east locations, respectively

  3. On the '-1' scaling of air temperature spectra in atmospheric surface layer flows

    Science.gov (United States)

    Li, D.; Katul, G. G.; Gentine, P.

    2015-12-01

    The spectral properties of scalar turbulence at high wavenumbers have been extensively studied in turbulent flows, and existing theories explaining the k-5/3 scaling within the inertial subrange appear satisfactory at high Reynolds numbers. Equivalent theories for the low wavenumber range have been comparatively lacking because boundary conditions prohibit attainment of such universal behavior. A number of atmospheric surface layer (ASL) experiments reported a k-1 scaling in air temperature spectra ETT(k) at low wavenumbers but other experiments did not. Here, the occurrence of a k-1 scaling in ETT(k) in an idealized ASL flow across a wide range of atmospheric stability regimes is investigated theoretically and experimentally. Experiments reveal a k-1 scaling persisted across different atmospheric stability parameter values (ζ) ranging from mildly unstable to mildly stable conditions (-0.1budget models and upon using a Heisenberg eddy viscosity as a closure to the spectral flux transfer term, conditions promoting a k-1 scaling are identified. Existence of a k-1 scaling is shown to be primarily linked to an imbalance between the production and dissipation rates of half the temperature variance. The role of the imbalance between the production and dissipation rates of half the temperature variance in controlling the existence of a '-1' scaling suggests that the '-1' scaling in ETT(k) does not necessarily concur with the '-1' scaling in the spectra of longitudinal velocity Euu(k). This finding explains why some ASL experiments reported k-1 in Euu(k) but not ETT(k). It also differs from prior arguments derived from directional-dimensional analysis that lead to simultaneous k-1 scaling in Euu(k) and ETT(k) at low wavenumbers in a neutral ASL.

  4. An estimate of the impact of transient luminous events on the atmospheric temperature

    Directory of Open Access Journals (Sweden)

    E. Arnone

    2008-09-01

    Full Text Available We present an order of magnitude estimate of the impact of sprites and other transient luminous events (TLEs on the atmospheric temperature via ozone changes. To address the effects of expected TLE-ozone changes of at most a few percent, we first study the linearity of the radiatively driven response of a stratosphere-mesosphere model and of a general circulation model (GCM to a range of uniform climatological ozone perturbations. The study is limited to Northern Hemisphere winter conditions, when planetary wave activity is high and the non linear stratosphere-troposphere coupling can be strong. Throughout most of the middle atmosphere of both models, the radiatively driven temperature response to uniform 5% to 20% ozone perturbations shows a close-to linear relationship with the magnitude of the perturbation. A mid-latitude stratopause ozone perturbation is then imposed as an idealised experiment that mimics local temperature gradients introduced by the latitudinal dependence of TLEs. An unrealistically high 20% magnitude is adopted for the regional ozone perturbation to obtain statistical significance in the model response. The local linearity of the radiatively driven response is used to infer a first order estimate of TLE-induced temperature changes of the order of 0.015 K under typical conditions, and less than a peak temperature change of 0.3 K at 60–70 km height in coincidence of extraordinarily active TLE-producing thunderstorms before horizontal mixing quickly occurs. In the latter case, dedicated mesoscale modelling is needed to study the relevance of regional non linear processes which are expected to impact these radiatively driven responses.

  5. Mechanical characterisation of tungsten–1 wt.% yttrium oxide as a function of temperature and atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, T.; Jiménez, A. [Materials Science Department, Technical University of Madrid, E.T.S. de Ingenieros de Caminos, Canales y Puertos, C/Profesor Aranguren s/n, 28040 Madrid (Spain); Muñóz, A.; Monge, M.A.; Ballesteros, C. [Departamento de Física, Universidad Carlos III de Madrid, Leganés (Spain); Pastor, J.Y. [Materials Science Department, Technical University of Madrid, E.T.S. de Ingenieros de Caminos, Canales y Puertos, C/Profesor Aranguren s/n, 28040 Madrid (Spain)

    2014-11-15

    This study evaluates the mechanical behaviour of an Y{sub 2}O{sub 3}-dispersed tungsten (W) alloy and compares it to a pure W reference material. Both materials were processed via mechanical alloying (MA) and subsequent hot isostatic pressing (HIP). We performed non-standard three-point bending (TPB) tests in both an oxidising atmosphere and vacuum across a temperature range from 77 K, obtained via immersion in liquid nitrogen, to 1473 K to determine the mechanical strength, yield strength and fracture toughness. This research aims to evaluate how the mechanical behaviour of the alloy is affected by oxides formed within the material at high temperatures, primarily from 873 K, when the materials undergo a massive thermal degradation. The results indicate that the alloy is brittle to a high temperature (1473 K) under both atmospheres and that the mechanical properties degrade significantly above 873 K. We also used Vickers microhardness tests and the dynamic modulus by impulse excitation technique (IET) to determine the elastic modulus at room temperature. Moreover, we performed nanoindentation tests to determine the effect of size on the hardness and elastic modulus; however, no significant differences were found. Additionally, we calculated the relative density of the samples to assess the porosity of the alloy. Finally, we analysed the microstructure and fracture surfaces of the tested materials via field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). In this way, the relationship between the macroscopic mechanical properties and micromechanisms of failure could be determined based on the temperature and oxides formed.

  6. A case study of multi-annual temperature oscillations in the atmosphere: Middle Europe

    Science.gov (United States)

    Offermann, D.; Goussev, O.; Kalicinsky, Ch.; Koppmann, R.; Matthes, K.; Schmidt, H.; Steinbrecht, W.; Wintel, J.

    2015-12-01

    SABER temperature measurements from 2002 to 2012 are analyzed from 18 to 110 km altitude in Middle Europe. Data are complemented by radiosonde measurements in the altitude range from 0 to 30 km. Low frequency oscillations with periods of about 2.4-2.2 yr, 3.4 yr, and 5.5 yr are seen in either data set. Surprising vertical structures in amplitudes and phases are observed with alternating minima and maxima of amplitudes, steep phase changes (180°) at the altitudes of the minima, and constant phase values in between. HAMMONIA CCM simulations driven by boundary conditions for the years 1996-2006 are analyzed for corresponding features, and very similar structures are found. Data from another CCM, the CESM-WACCM model, are also analyzed and show comparable results. Similar oscillation periods have been reported in the literature for the ocean. A possible forcing of the atmospheric oscillations from below was therefore tested with a special HAMMONIA run. Here, climatological boundary conditions were used, i.e. the boundaries in all eleven years were the same. Surprisingly also in this data set the same atmospheric oscillations are obtained. We therefore conclude that the oscillations are intrinsically forced, self-sustained in the atmosphere. The oscillations turned out to be quite robust as they are still found in a HAMMONIA run with strongly reduced vertical resolution. Here only the form of the vertical amplitude and phase profile of the 2.2 yr feature is lost but the oscillation itself is still there, and the two other oscillations are essentially unchanged. Similar oscillations are seen in the earth surface temperatures. Global Land Ocean Temperature Index data (GLOTI) reaching back to 1880 show such oscillations during all that time. The oscillations are also seen in parameters other than atmospheric temperature. They are found in surface data such as the North Atlantic Oscillation Index (NAO) and in zonal winds in the troposphere and lower stratosphere. The

  7. Observation of semiannual and annual oscillation in equatorial middle atmospheric long term temperature pattern

    OpenAIRE

    A. Guharay; D. Nath; Pant, P.; B. Pande; Russell, J.M.; Pandey, K

    2009-01-01

    Extensive measurement of middle atmospheric temperature with the help of lidar data of more than 10 years (1998–2008) and TIMED/SABER data of 7 years (2002–2008), has been carried out from a low latitude station, Gadanki, India (13.5° N, 79.2° E), which exhibits the presence of semiannual oscillation (SAO) and annual oscillation (AnO). The AnO component is stronger in the mesospheric region (80–90 km) and the SAO is dominant at stratospheric altitudes (30–50 km). Overall, the ...

  8. Surface modification of non-fabricated polypropylene textile in low-temperature plasma at atmospheric pressure

    International Nuclear Information System (INIS)

    The plasma activation of polypropylene (PP) non-fabricated textile in low temperature plasma at atmospheric pressure has been studied. The aim of the present work was the study of the surface modification of non-fabricated textiles in order to improve their hydrophilic properties. The surface treatment has been provided by nonequilibrium discharges as barrier discharge and surface discharge. The surface properties have been characterized by measuring the contact angle of PP textiles with liquid, standard industrial permeability measurements and absorption tests. The degradation of treated PP samples has also been studied. (author)

  9. Electron Density and Temperature Measurements, and Abundance Anomalies in the Solar Atmosphere

    Indian Academy of Sciences (India)

    Anita Mohan; Bhola N. Dwivedi; Enrico Landi

    2000-09-01

    Using spectra obtained from the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrograph on the spacecraft SOHO (Solar and Heliospheric Observatory), we investigate the height dependence of electron density, temperature and abundance anomalies in the solar atmosphere. In particular, we present the behaviour of the solar FIP effect (the abundance enhancement of elements with first ionization potential < 10 eV in the corona with respect to photospheric values) with height above an active region observed at the solar limb, with emphasis on the so-called transition region lines.

  10. Surface modification of the nanoparticles by an atmospheric room-temperature plasma fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Chen Guangliang [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)], E-mail: glchen@zstu.edu.cn; Chen Shihua [Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY 13244 (United States); Feng Wenran [Department of Materials Science and Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617 (China); Chen Wenxing [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Yang Size [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2008-04-30

    Using hexamethyldisiloxane (HMDSO) monomer, the magnetic nanoparticles (NPs) of nickel oxide (NiO) were modified by using an atmospheric room-temperature plasma fluidized bed (ARPFB). The plasma gas temperature of the ARPFB was not higher than 325 K, which was favorable for organic polymerization. The plasma optical emission spectrum (OES) of the gas mixture consisting of argon (Ar) and HMDSO was recorded by a UV-visible monochromator. The as-treated NPs were characterized by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the assembling NPs were isolated greatly after modified by the organosilicon polymer. Moreover, this treatment process changed the wettability of the NPs from super-hydrophilicity to super-hydrophobicity, and the contact angle (CA) of water on the modified NPs surface exceeded 150 deg. Therefore, the ARPFB is a prospective technology for the NPs surface modification according to the different requirements.

  11. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere.

    Science.gov (United States)

    Makowska, Małgorzata G; Theil Kuhn, Luise; Cleemann, Lars N; Lauridsen, Erik M; Bilheux, Hassina Z; Molaison, Jamie J; Santodonato, Louis J; Tremsin, Anton S; Grosse, Mirco; Morgano, Manuel; Kabra, Saurabh; Strobl, Markus

    2015-12-01

    High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. This paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 °C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. This covers a broad field of research from fundamental to technological investigations of various types of materials and components. PMID:26724075

  12. Electron density and temperature measurement by continuum radiation emitted from weakly ionized atmospheric pressure plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sanghoo; Choe, Wonho, E-mail: wchoe@kaist.ac.kr [Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Youn Moon, Se [High-enthalpy Plasma Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju 561-756 (Korea, Republic of); Park, Jaeyoung [5771 La Jolla Corona Drive, La Jolla, CA 92037 (United States)

    2014-02-24

    The electron-atom neutral bremsstrahlung continuum radiation emitted from weakly ionized plasmas is investigated for electron density and temperature diagnostics. The continuum spectrum in 450–1000 nm emitted from the argon atmospheric pressure plasma is found to be in excellent agreement with the neutral bremsstrahlung formula with the electron-atom momentum transfer cross-section given by Popović. In 280–450 nm, however, a large discrepancy between the measured and the neutral bremsstrahlung emissivities is observed. We find that without accounting for the radiative H{sub 2} dissociation continuum, the temperature, and density measurements would be largely wrong, so that it should be taken into account for accurate measurement.

  13. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Makowska, Małgorzata G., E-mail: malg@dtu.dk [Department of Energy Conversion and Storage, Technical University of Denmark, Roskilde 4000 (Denmark); European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); Theil Kuhn, Luise; Cleemann, Lars N. [Department of Energy Conversion and Storage, Technical University of Denmark, Roskilde 4000 (Denmark); Lauridsen, Erik M. [Xnovo Technology ApS, Galoche Alle 15, Køge 4600 (Denmark); Bilheux, Hassina Z.; Molaison, Jamie J.; Santodonato, Louis J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Tremsin, Anton S. [Space Sciences Laboratory, University of California at Berkeley, Berkeley, California 94720 (United States); Grosse, Mirco [Institute for Applied Material Research, Karlsruhe Institute of Technology, Karlsruhe DE-76021 (Germany); Morgano, Manuel [Paul Scherrer Institut, Villigen PSI CH-5232 (Switzerland); Kabra, Saurabh [ISIS, Rutherford Appleton Laboratory, Chilton OX11 0QX (United Kingdom); Strobl, Markus [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden)

    2015-12-15

    High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. This paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 °C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. This covers a broad field of research from fundamental to technological investigations of various types of materials and components.

  14. Synergy between middle infrared and millimeter-wave limb sounding of atmospheric temperature and minor constituents

    Science.gov (United States)

    Cortesi, Ugo; Del Bianco, Samuele; Ceccherini, Simone; Gai, Marco; Dinelli, Bianca Maria; Castelli, Elisa; Oelhaf, Hermann; Woiwode, Wolfgang; Höpfner, Michael; Gerber, Daniel

    2016-05-01

    Synergistic exploitation of redundant and complementary information from independent observations of the same target remains a major issue in atmospheric remote sounding and increasing attention is devoted to investigate optimized or innovative methods for the combination of two or more measured data sets. This paper focuses on the synergy between middle infrared and millimeter-wave limb sounding measurements of atmospheric composition and temperature and reports the results of a study conducted as part of the preparatory activities of the PREMIER (Process Exploration through Measurements of Infrared and millimeter-wave Emitted Radiation) mission candidate to the Core Missions of the European Space Agency (ESA) Earth Explorer 7. The activity was based on data acquired by the MIPAS-STR (Michelson Interferometer for Passive Atmospheric Sounding - STRatospheric aircraft) and MARSCHALS (Millimetre-wave Airborne Receivers for Spectroscopic CHaracterisation in Atmospheric Limb Sounding) instruments on-board the high-altitude research aircraft M-55 Geophysica during the flight of the PremierEx (PREMIER Experiment) campaign on 10 March 2010 from Kiruna, Sweden, for observation of the Arctic upper troposphere and lower stratosphere. The cloud coverage observed along the flight provided representative test cases to evaluate the synergy in three different scenarios: low clouds in the first part, no clouds in the central part and high tropospheric clouds at the end. The calculation of synergistic profiles of four atmospheric targets (i.e., O3, HNO3, H2O and temperature) was performed using a posteriori combination of individual retrieved profiles, i.e., Level 2 (L2) data rather than simultaneous inversion of observed radiances, i.e., Level 1 (L1) data. An innovative method of data fusion, based on the Measurement Space Solution (MSS) was applied along with the standard approach of inversion of MARSCHALS spectral radiances using MIPAS-STR retrieval products as a priori

  15. Climate change scenarios of extreme temperatures and atmospheric humidity for Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Tejeda-Martinez, A. [Departamento de Ciencias Atmosfericas, Universidad Veracruzana, Xalapa, Veracruz (Mexico)]. E-mail: atejeda@uv.mx; Conde-Alvarez, C. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico); Valencia-Treviso, L.E. [Departamento de Ciencias Atmosfericas, Universidad Veracruzana, Xalapa, Veracruz (Mexico)

    2008-10-15

    The following study explores climatic change scenarios of extreme temperature and atmospheric humidity for the 2020 and 2050 decades. They were created for Mexico through the GFDLR30, ECHAM4 and HadCM2 general circulation models. Base scenario conditions were associated with the normal climatological conditions for the period 1961-1990, with a database of 50 surface observatories. It was necessary to empirically estimate the missing data in approximately half of the pressure measurements. For the period 1961-1990, statistical models of the monthly means of maximum and minimum temperatures and atmospheric humidity (relative and specific) were obtained from the observed data of temperature, solar radiation and precipitation. Based on the simulations of the GFDLR30, ECHAM4 and HADCM2 models, a future scenario of monthly means of maximum and minimum temperatures and humidity in climatic change conditions was created. The results shown are for the representative months of winter (January) and summer (July). [Spanish] En este articulo se presentan escenarios de cambio climatico referidos a temperaturas extremas y humedad atmosferica para las decadas de 2020 y 2050. Fueron generados para Mexico a partir de los modelos de circulacion general GFDLR30, ECHAM4 y HADCM2. El escenario base corresponde a las normales climatologicas del periodo 1961-1990 para 50 observatorios de superficie. Para la mitad de ellos fue necesario estimar empiricamente la presion atmosferica a partir de la altitud y para la totalidad se obtuvieron modelos estadisticos de los promedios mensuales de temperaturas maxima y minima asi como de humedad atmosferica (relativa y especifica). Esos modelos estadisticos, combinados con las salidas de los modelos de circulacion general mencionados, produjeron escenarios futuros de medias mensuales de temperaturas extremas y de humedad bajo condiciones de cambio climatico. Se mostraran los resultados para un mes representativo del invierno (enero) y otro del verano

  16. Organic particulate material levels in the atmosphere: conditions favoring sensitivity to varying relative humidity and temperature.

    Science.gov (United States)

    Pankow, James F

    2010-04-13

    This study examines the sensitivity in predicted levels of atmospheric organic particulate matter (M(o), microg m(-3)) as those levels may potentially be affected by changes in relative humidity and temperature. In a given system, for each partitioning compound, f(g) and f(p) represent the gaseous and particulate fractions (f(g) + f(p) = 1). Sensitivity in the M(o) levels becomes dampened as the compounds contributing significantly to M(o) are increasingly found in the particle phase (f(p) --> 1). Thus, although local maxima in sensitivity can be encountered as M(o) levels increase, because as M(o) increases each f(p) --> 1, then increasing M(o) levels generally tend to reduce sensitivity in M(o) levels to changes in relative humidity and temperature. Experiments designed to elucidate the potential magnitudes of the effects of relative humidity and temperature on M(o) levels must be carried out at M(o) levels that are relevant for the ambient atmosphere: The f(p) values for the important partitioning compounds must not be elevated above ambient-relevant values. Systems in which M(o) levels are low (e.g., 1-2 microg m(-3)) and/or composed of unaged secondary organic aerosol are the ones most likely to show sensitivity to changing relative humidity and temperature. Results from two published chamber studies are examined in the above regard: [Warren B, et al. (2009) Atmos Environ 43:1789-1795] and [Prisle NL, et al. (2010) Geophys Res Lett 37:L01802].

  17. Denali Ice Core Record of North Pacific Hydroclimate, Temperature and Atmospheric Circulation over the Past Millennium

    Science.gov (United States)

    Osterberg, E. C.; Wake, C. P.; Kreutz, K. J.; Winski, D.; Ferris, D. G.; Introne, D.; Campbell, S.; Birkel, S. D.

    2015-12-01

    While tree ring and lake sediment core studies have revealed a great deal about North Pacific (e.g. Alaska) surface temperature variability over the past millennium, we do not have an equivalent understanding of North Pacific hydroclimate variability or temperatures at high elevations. A millennial-length precipitation proxy record is needed to place late 20th century Alaskan precipitation increases into longer context, and to evaluate hydroclimate changes during the Little Ice Age and Medieval Climate Anomaly. High-elevation summer temperature records would be valuable for understanding the sensitivity of Alaskan glaciers to past warm and cool periods. Here we present an overview of the new Denali Ice Core record collected from the summit plateau (4000 m a.s.l.) of Mt. Hunter (63° N, 151° W) in Denali National Park, Alaska. Two parallel ice cores were collected to bedrock (208 m in length) in May-June 2013, sampled using the Dartmouth continuous melter system, and analyzed for major ions, trace elements, particle concentration and size distribution, and stable isotope ratios at Dartmouth and the Universities of Maine and New Hampshire. The cores are dated using robust annual oscillations in dust elements, methanesulfonate, ammonium, and stable isotopes, and validated using major volcanic eruptions recorded as sulfate, chloride and heavy metal spikes, and the 1963 nuclear weapons testing 137Cs spike. Preliminary analyses indicate a significant increase in both summer temperature and annual accumulation over the 20th century, and significant relationships with major ocean-atmospheric modes including the Pacific Decadal Oscillation. We compare the new Denali record to the Eclipse Icefield and Mt. Logan ice core records and develop composite records of North Pacific hydroclimate and atmospheric circulation variability over the past millennium.

  18. Multitechnique characterisation of 304L surface states oxidised at high temperature in steam and air atmospheres

    Science.gov (United States)

    Mamede, Anne-Sophie; Nuns, Nicolas; Cristol, Anne-Lise; Cantrel, Laurent; Souvi, Sidi; Cristol, Sylvain; Paul, Jean-François

    2016-04-01

    In case of a severe accident occurring in a nuclear reactor, surfaces of the reactor coolant system (RCS), made of stainless steel (304L) rich in Cr (>10%) and Ni (8-12%), are oxidised. Fission products (FPs) are released from melt fuel and flow through the RCS. A part of them is deposited onto surfaces either by vapour condensation or by aerosol deposition mechanisms. To be able to understand the nature of interactions between these FPs and the RCS surfaces, a preliminary step is to characterize the RSC surface states in steam and air atmosphere at high temperatures. Pieces of 304L stainless steel have been treated in a flow reactor at two different temperatures (750 °C and 950 °C) for two different exposition times (24 h and 72 h). After surfaces analysing by a unique combination of surface analysis techniques (XPS, ToF-SIMS and LEIS), for 304L, the results show a deep oxide scale with multi layers and the outer layer is composed of chromium and manganese oxides. Oxide profiles differ in air or steam atmosphere. Fe2O3 oxide is observed but in minor proportion and in all cases no nickel is detected near the surface. Results obtained are discussed and compared with the literature data.

  19. Manganese oxide phases and morphologies: A study on calcination temperature and atmospheric dependence

    Directory of Open Access Journals (Sweden)

    Matthias Augustin

    2015-01-01

    Full Text Available Manganese oxides are one of the most important groups of materials in energy storage science. In order to fully leverage their application potential, precise control of their properties such as particle size, surface area and Mnx+ oxidation state is required. Here, Mn3O4 and Mn5O8 nanoparticles as well as mesoporous α-Mn2O3 particles were synthesized by calcination of Mn(II glycolate nanoparticles obtained through an economical route based on a polyol synthesis. The preparation of the different manganese oxides via one route facilitates assigning actual structure–property relationships. The oxidation process related to the different MnOx species was observed by in situ X-ray diffraction (XRD measurements showing time- and temperature-dependent phase transformations occurring during oxidation of the Mn(II glycolate precursor to α-Mn2O3 via Mn3O4 and Mn5O8 in O2 atmosphere. Detailed structural and morphological investigations using transmission electron microscopy (TEM and powder XRD revealed the dependence of the lattice constants and particle sizes of the MnOx species on the calcination temperature and the presence of an oxidizing or neutral atmosphere. Furthermore, to demonstrate the application potential of the synthesized MnOx species, we studied their catalytic activity for the oxygen reduction reaction in aprotic media. Linear sweep voltammetry revealed the best performance for the mesoporous α-Mn2O3 species.

  20. Retrieving Atmospheric Temperature and Moisture Profiles from NPP CRIS/ATMS Sensors Using Crimss EDR Algorithm

    Science.gov (United States)

    Liu, X.; Kizer, S.; Barnet, C.; Dvakarla, M.; Zhou, D. K.; Larar, A. M.

    2012-01-01

    The Joint Polar Satellite System (JPSS) is a U.S. National Oceanic and Atmospheric Administration (NOAA) mission in collaboration with the U.S. National Aeronautical Space Administration (NASA) and international partners. The NPP Cross-track Infrared Microwave Sounding Suite (CrIMSS) consists of the infrared (IR) Crosstrack Infrared Sounder (CrIS) and the microwave (MW) Advanced Technology Microwave Sounder (ATMS). The CrIS instrument is hyperspectral interferometer, which measures high spectral and spatial resolution upwelling infrared radiances. The ATMS is a 22-channel radiometer similar to Advanced Microwave Sounding Units (AMSU) A and B. It measures top of atmosphere MW upwelling radiation and provides capability of sounding below clouds. The CrIMSS Environmental Data Record (EDR) algorithm provides three EDRs, namely the atmospheric vertical temperature, moisture and pressure profiles (AVTP, AVMP and AVPP, respectively), with the lower tropospheric AVTP and the AVMP being JPSS Key Performance Parameters (KPPs). The operational CrIMSS EDR an algorithm was originally designed to run on large IBM computers with dedicated data management subsystem (DMS). We have ported the operational code to simple Linux systems by replacing DMS with appropriate interfaces. We also changed the interface of the operational code so that we can read data from both the CrIMSS science code and the operational code and be able to compare lookup tables, parameter files, and output results. The detail of the CrIMSS EDR algorithm is described in reference [1]. We will present results of testing the CrIMSS EDR operational algorithm using proxy data generated from the Infrared Atmospheric Sounding Interferometer (IASI) satellite data and from the NPP CrIS/ATMS data.

  1. High temperature corrosion in chloridizing atmospheres: development of material quasi-stability diagrams and coatings

    Energy Technology Data Exchange (ETDEWEB)

    Doublet, S.; Schuetze, M. [Karl-Winnacker-Institut der DECHEMA e.V., Theodor-Heuss-Allee 25, D-60486 Frankfurt am Main (Germany)

    2004-07-01

    Chlorine gas is widely encountered in chemical industries, e. g. in waste incinerators and plastic/polymer decomposition mills. The presence of chlorine may significantly reduce the life-time of the components. Although metallic materials have been widely used under such conditions there is still a need for data on the role of the different alloying elements in commercial alloys. The purpose of this work is to produce a clear picture of which alloying elements play a detrimental role and which elements are beneficial. These results can be used as a tool for general assessment of metallic alloys with regard to their performance in chloridizing high temperature environments. A previous study has already been performed in oxidizing-chloridizing atmospheres and led to the elaboration of material quasi-stability diagrams. As a follow-up the present work has been performed in reducing-chloridizing atmospheres in order to validate these diagrams at low partial pressures of oxygen. The behaviour of 9 commercial materials where the content of the major alloying elements was varied in a systematic manner was investigated in reducing-chloridizing atmospheres (in Ar containing up to 2 vol.% Cl{sub 2} and down to 1 ppm O{sub 2}) at 800 deg. C. As the thermodynamical approach to corrosion in such atmospheres could not explain all the phenomena which occur, kinetics calculations i.e. diffusion calculations were carried out. Pack cementation and High Velocity Oxy-Fuel (HVOF) coatings were also developed from the best alloying elements previously found by the calculations and the corrosion experiments. Corrosion tests on the coated materials were then performed in the same conditions as the commercial alloys. (authors)

  2. Atmospheric temperature in the Venus mesosphere, investigated by VIRTIS/Venus Express

    Science.gov (United States)

    Migliorini, A.; Grassi, D.; Piccioni, G.; Lebonnois, S.; Montabone, L.; Drossart, P.

    2012-04-01

    Atmospheric temperature, retrieved using remote sensing data acquired with the VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) instrument on board the European Venus Express mission, is presented for the night side of Venus both in the northern and southern hemispheres of the planet. The explored pressure range covers from 100 to 4 mbar, corresponding approximately to the altitude range from 65 to 80 km. Differences between the dusk and dawn sides are observed in the temperature values, the dawn being the coldest quadrant in the pressure range 100 to 12 mbar. The most important observed feature is the cold-collar region around 60-70°, which is 15 to 20 K colder than the temperature at the pole at 100 mbar (about 65 km), also showing a significant thermal inversion. A peculiar pattern of maxima and minima in temperature is observed at 100 and 12 mbar. The application of a global circulation model (Lebonnois et al., 2010) to our data allows to interpret the observed features as indication of diurnal and/or semidiurnal thermal tides (Migliorini et al., 2011).

  3. High atmospheric temperatures and 'ambient incubation' drive embryonic development and lead to earlier hatching in a passerine bird.

    Science.gov (United States)

    Griffith, Simon C; Mainwaring, Mark C; Sorato, Enrico; Beckmann, Christa

    2016-02-01

    Tropical and subtropical species typically experience relatively high atmospheric temperatures during reproduction, and are subject to climate-related challenges that are largely unexplored, relative to more extensive work conducted in temperate regions. We studied the effects of high atmospheric and nest temperatures during reproduction in the zebra finch. We characterized the temperature within nests in a subtropical population of this species in relation to atmospheric temperature. Temperatures within nests frequently exceeded the level at which embryo's develop optimally, even in the absence of parental incubation. We experimentally manipulated internal nest temperature to demonstrate that an average difference of 6°C in the nest temperature during the laying period reduced hatching time by an average of 3% of the total incubation time, owing to 'ambient incubation'. Given the avian constraint of laying a single egg per day, the first eggs of a clutch are subject to prolonged effects of nest temperature relative to later laid eggs, potentially increasing hatching asynchrony. While birds may ameliorate the negative effects of ambient incubation on embryonic development by varying the location and design of their nests, high atmospheric temperatures are likely to constitute an important selective force on avian reproductive behaviour and physiology in subtropical and tropical regions, particularly in the light of predicted climate change that in many areas is leading to a higher frequency of hot days during the periods when birds breed. PMID:26998315

  4. High atmospheric temperatures and ‘ambient incubation’ drive embryonic development and lead to earlier hatching in a passerine bird

    Science.gov (United States)

    Griffith, Simon C.; Mainwaring, Mark C.; Sorato, Enrico; Beckmann, Christa

    2016-01-01

    Tropical and subtropical species typically experience relatively high atmospheric temperatures during reproduction, and are subject to climate-related challenges that are largely unexplored, relative to more extensive work conducted in temperate regions. We studied the effects of high atmospheric and nest temperatures during reproduction in the zebra finch. We characterized the temperature within nests in a subtropical population of this species in relation to atmospheric temperature. Temperatures within nests frequently exceeded the level at which embryo’s develop optimally, even in the absence of parental incubation. We experimentally manipulated internal nest temperature to demonstrate that an average difference of 6°C in the nest temperature during the laying period reduced hatching time by an average of 3% of the total incubation time, owing to ‘ambient incubation’. Given the avian constraint of laying a single egg per day, the first eggs of a clutch are subject to prolonged effects of nest temperature relative to later laid eggs, potentially increasing hatching asynchrony. While birds may ameliorate the negative effects of ambient incubation on embryonic development by varying the location and design of their nests, high atmospheric temperatures are likely to constitute an important selective force on avian reproductive behaviour and physiology in subtropical and tropical regions, particularly in the light of predicted climate change that in many areas is leading to a higher frequency of hot days during the periods when birds breed. PMID:26998315

  5. Model atmospheres broad-band colors, bolometric corrections and temperature calibrations for O - M stars

    Science.gov (United States)

    Bessell, M. S.; Castelli, F.; Plez, B.

    1998-05-01

    Broad band colors and bolometric corrections in the Johnson-Cousins-Glass system (Bessell, 1990; Bessell & Brett, 1988) have been computed from synthetic spectra from new model atmospheres of Kurucz (1995a), Castelli (1997), Plez, Brett & Nordlund (1992), Plez (1995-97), and Brett (1995a,b). These atmospheres are representative of larger grids that are currently being completed. We discuss differences between the different grids and compare theoretical color-temperature relations and the fundamental color temperature relations derived from: (a) the infrared-flux method (IRFM) for A-K stars (Blackwell & Lynas-Gray 1994; Alonso et al. 1996) and M dwarfs (Tsuji et al. 1996a); (b) lunar occultations (Ridgway et al. 1980) and (c) Michelson interferometry (Di Benedetto & Rabbia 1987; Dyck et al. 1996; Perrin et al. 1997) for K-M giants, and (d) eclipsing binaries for M dwarfs. We also compare color - color relations and color - bolometric correction relations and find good agreement except for a few colors. The more realistic fluxes and spectra of the new model grids should enable accurate population synthesis models to be derived and permit the ready calibration of non-standard photometric passbands. As well, the theoretical bolometric corrections and temperature - color relations will permit reliable transformation from observed color magnitude diagrams to theoretical HR diagrams. Tables 1-6 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

  6. A novel atmospheric Temperature Sounding Unit: system design and performance analyses

    Science.gov (United States)

    Chakraborty, Prantik; Gupta, Priyanka; Dave, Dilip B.; Desai, Nilesh M.; Misra, Tapan

    2016-05-01

    This paper reports the development of a millimeter-wave space-borne atmospheric Temperature Sounding Unit (TSU) in Indian Space Research Organization (ISRO). This is ISRO's first leap towards millimeter-wave technology. The sensor has several new accomplishments to its credit which include among others, the philosophy of sounding channel selection, the new assortment of temperature sounding channels, simultaneous observation of both polarizations of all channels, compact dual-band scanning Gregorian reflector antenna, indigenously developed black-body target for in-orbit calibration, in-house developed millimeter-wave RF front-end and pre-detection automatic gain control method. The prime feature of this instrument is its unique set of channels which can profile the earth's atmosphere from surface to 40 km altitude with vertical resolution ranging from less than a km near surface to +/-2.5 km at 30km altitude. The channels are predominantly off-resonant frequencies in the 50―60 GHz O2 absorption spectrum which offer near-uniform attenuation and hence more channel-bandwidth and better temperature sensitivity and yet have adequate overlap of their weighting functions to achieve the desired vertical resolution. These channels are different and have fewer bands from what has been flown in all earlier sounding missions worldwide e.g. AMSU-A, SSMIS, ATMS etc. The TSU radiometer has been characterized thoroughly using ingenious methods such as low-power active RF energizing along with frequency sweep. This is a compact, low-mass, low-power instrument and has been configured for the ISRO mini-satellite (IMS-2) bus. The flight model with improved hardware performance is being built and a suitable opportunity of flying it is being explored.

  7. ATMOSPHERIC IMAGING ASSEMBLY OBSERVATIONS OF CORONAL LOOPS: CROSS-FIELD TEMPERATURE DISTRIBUTIONS

    International Nuclear Information System (INIS)

    We construct revised response functions for the Atmospheric Imaging Assembly (AIA) using the new atomic data, ionization equilibria, and coronal abundances available in CHIANTI 7.1. We then use these response functions in multithermal analysis of coronal loops, which allows us to determine a specific cross-field temperature distribution without ad hoc assumptions. Our method uses data from the six coronal filters and the Monte Carlo solutions available from our differential emission measure (DEM) analysis. The resulting temperature distributions are not consistent with isothermal plasma. Therefore, the observed loops cannot be modeled as single flux tubes and must be composed of a collection of magnetic strands. This result is now supported by observations from the High-resolution Coronal Imager, which show fine-scale braiding of coronal strands that are reconnecting and releasing energy. Multithermal analysis is one of the major scientific goals of AIA, and these results represent an important step toward the successful achievement of that goal. As AIA DEM analysis becomes more straightforward, the solar community will be able to take full advantage of the state-of-the-art spatial, temporal, and temperature resolution of the instrument.

  8. Inactivation of Gram-positive biofilms by low-temperature plasma jet at atmospheric pressure

    Science.gov (United States)

    Marchal, F.; Robert, H.; Merbahi, N.; Fontagné-Faucher, C.; Yousfi, M.; Romain, C. E.; Eichwald, O.; Rondel, C.; Gabriel, B.

    2012-08-01

    This work is devoted to the evaluation of the efficiency of a new low-temperature plasma jet driven in ambient air by a dc-corona discharge to inactivate adherent cells and biofilms of Gram-positive bacteria. The selected microorganisms were lactic acid bacteria, a Weissella confusa strain which has the particularity to excrete a polysaccharide polymer (dextran) when sucrose is present. Both adherent cells and biofilms were treated with the low-temperature plasma jet for different exposure times. The antimicrobial efficiency of the plasma was tested against adherent cells and 48 h-old biofilms grown with or without sucrose. Bacterial survival was estimated using both colony-forming unit counts and fluorescence-based assays for bacterial cell viability. The experiments show the ability of the low-temperature plasma jet at atmospheric pressure to inactivate the bacteria. An increased resistance of bacteria embedded within biofilms is clearly observed. The resistance is also significantly higher with biofilm in the presence of sucrose, which indicates that dextran could play a protective role.

  9. Climate change and agroecosystems: the effect of elevated atmospheric CO2 and temperature on crop growth, development, and yield

    Directory of Open Access Journals (Sweden)

    Streck Nereu Augusto

    2005-01-01

    Full Text Available The amount of carbon dioxide (CO2 of the Earths atmosphere is increasing, which has the potential of increasing greenhouse effect and air temperature in the future. Plants respond to environment CO2 and temperature. Therefore, climate change may affect agriculture. The purpose of this paper was to review the literature about the impact of a possible increase in atmospheric CO2 concentration and temperature on crop growth, development, and yield. Increasing CO2 concentration increases crop yield once the substrate for photosynthesis and the gradient of CO2 concentration between atmosphere and leaf increase. C3 plants will benefit more than C4 plants at elevated CO2. However, if global warming will take place, an increase in temperature may offset the benefits of increasing CO2 on crop yield.

  10. Investigating Titan's Atmospheric Chemistry at Low Temperature with the Titan Haze Simulation Experiment

    Science.gov (United States)

    Sciamma-O'Brien, E. M.; Salama, F.

    2012-12-01

    Titan, Saturn's largest satellite, possesses a dense atmosphere (1.5 bar at the surface) composed mainly of N2 and CH4. The solar radiation and electron bombardment from Saturn's magnetosphere induces a complex organic chemistry between these two constituents leading to the production of more complex molecules and subsequently to solid aerosols. These aerosols in suspension in the atmosphere form the haze layers giving Titan its characteristic orange color. Since 2004, the instruments onboard the Cassini orbiter have produced large amounts of observational data, unraveling a chemistry much more complex than what was first expected, particularly in Titan's upper atmosphere. Neutral, positively and negatively charged heavy molecules have been detected in the ionosphere of Titan, including benzene (C6H6) and toluene (C6H5CH3). The presence of these critical precursors of polycyclic aromatic hydrocarbon (PAH) compounds suggests that PAHs might play a role in the production of Titan's aerosols. The aim of the Titan Haze Simulation (THS) experiment, developed at the NASA Ames COSmIC facility, is to study the chemical pathways that link the simple molecules resulting from the first steps of the N2-CH4 chemistry to benzene, and to PAHs and nitrogen-containing PAHs (PANHs) as precursors to the production of solid aerosols. In the THS experiment, Titan's atmospheric chemistry is simulated by plasma in the stream of a supersonic expansion. With this unique design, the gas mixture is cooled to Titan-like temperature (~150K) before inducing the chemistry by plasma discharge. Due to the short residence time of the gas in the plasma discharge, the THS experiment can be used to probe the first and intermediate steps of Titan's chemistry by injecting different gas mixtures in the plasma. The products of the chemistry are detected and studied using two complementary techniques: Cavity Ring Down Spectroscopy and Time-Of-Flight Mass Spectrometry. Thin tholin deposits are also produced

  11. Atmospheric pressure, density, temperature and wind variations between 50 and 200 km

    Science.gov (United States)

    Justus, C. G.; Woodrum, A.

    1972-01-01

    Data on atmospheric pressure, density, temperature and winds between 50 and 200 km were collected from sources including Meteorological Rocket Network data, ROBIN falling sphere data, grenade release and pitot tube data, meteor winds, chemical release winds, satellite data, and others. These data were analyzed by a daily difference method and results on the distribution statistics, magnitude, and spatial structure of the irregular atmospheric variations are presented. Time structures of the irregular variations were determined by the analysis of residuals from harmonic analysis of time series data. The observed height variations of irregular winds and densities are found to be in accord with a theoretical relation between these two quantities. The latitude variations (at 50 - 60 km height) show an increasing trend with latitude. A possible explanation of the unusually large irregular wind magnitudes of the White Sands MRN data is given in terms of mountain wave generation by the Sierra Nevada range about 1000 km west of White Sands. An analytical method is developed which, based on an analogy of the irregular motion field with axisymmetric turbulence, allows measured or model correlation or structure functions to be used to evaluate the effective frequency spectra of scalar and vector quantities of a spacecraft moving at any speed and at any trajectory elevation angle.

  12. Natural variability of atmospheric temperatures and geomagnetic intensity over a wide range of time scales.

    Science.gov (United States)

    Pelletier, Jon D

    2002-02-19

    The majority of numerical models in climatology and geomagnetism rely on deterministic finite-difference techniques and attempt to include as many empirical constraints on the many processes and boundary conditions applicable to their very complex systems. Despite their sophistication, many of these models are unable to reproduce basic aspects of climatic or geomagnetic dynamics. We show that a simple stochastic model, which treats the flux of heat energy in the atmosphere by convective instabilities with random advection and diffusive mixing, does a remarkable job at matching the observed power spectrum of historical and proxy records for atmospheric temperatures from time scales of one day to one million years (Myr). With this approach distinct changes in the power-spectral form can be associated with characteristic time scales of ocean mixing and radiative damping. Similarly, a simple model of the diffusion of magnetic intensity in Earth's core coupled with amplification and destruction of the local intensity can reproduce the observed 1/f noise behavior of Earth's geomagnetic intensity from time scales of 1 (Myr) to 100 yr. In addition, the statistics of the fluctuations in the polarity reversal rate from time scales of 1 Myr to 100 Myr are consistent with the hypothesis that reversals are the result of variations in 1/f noise geomagnetic intensity above a certain threshold, suggesting that reversals may be associated with internal fluctuations rather than changes in mantle thermal or magnetic boundary conditions. PMID:11875208

  13. Relationship between North American winter temperature and large-scale atmospheric circulation anomalies and its decadal variation

    Science.gov (United States)

    Yu, B.; Lin, H.; Wu, Z. W.; Merryfield, W. J.

    2016-07-01

    The interannual relationship between North American (NA) winter temperature and large-scale atmospheric circulation anomalies and its decadal variation are analyzed. NA temperature anomalies are dominated by two leading maximum covariance analysis (MCA) modes of NA surface temperature and Northern Hemisphere 500 hPa geopotential anomalies. A new teleconnection index, termed the Asian-Bering-North American (ABNA) pattern, is constructed from the normalized geopotential field after linearly removing the contribution of the Pacific-North American (PNA) pattern. The ABNA pattern is sustained by synoptic eddy forcing. The first MCA mode of NA surface temperature is highly correlated with the PNA and ABNA teleconnections, and the second mode with the North Atlantic Oscillation (NAO). This indicates that NA temperature is largely controlled by these three large-scale atmospheric patterns, i.e., the PNA, ABNA and NAO. These temperature-circulation relationships appear stationary in the 20th century.

  14. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    International Nuclear Information System (INIS)

    A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials

  15. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    Science.gov (United States)

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui; Zhang, Jue; Fang, Jing

    2015-10-01

    A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.

  16. On the magnetic field signal radiated by an atmospheric pressure room temperature plasma jet

    International Nuclear Information System (INIS)

    In this paper, the magnetic field signal radiated from an atmospheric pressure room temperature plasma plume is measured. It's found that the magnetic field signal has similar waveform as the current carried by the plasma plume. By calibration of the magnetic field signal, the plasma plume current is obtained by measuring the magnetic field signal radiated by the plasma plume. In addition, it is found that, when gas flow modes changes from laminar regime to turbulence regime, the magnetic field signal waveforms appears different, it changes from a smooth curve to a curve with multiple spikes. Furthermore, it is confirmed that the plasma plume generated by a single electrode (without ground electrode) plasma jet device carries higher current than that with ground electrode.

  17. Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device

    Science.gov (United States)

    Whalley, Richard D.; Walsh, James L.

    2016-08-01

    Flowing low temperature atmospheric pressure plasma devices have been used in many technological applications ranging from energy efficient combustion through to wound healing and cancer therapy. The generation of the plasma causes a sudden onset of turbulence in the inhomogeneous axisymmetric jet flow downstream of the plasma plume. The mean turbulent velocity fields are shown to be self-similar and independent of the applied voltage used to generate the plasma. It is proposed that the production of turbulence is related to a combination of the small-amplitude plasma induced body forces and gas heating causing perturbations in the unstable shear layers at the jet exit which grow as they move downstream, creating turbulence.

  18. Turbulent jet flow generated downstream of a low temperature dielectric barrier atmospheric pressure plasma device.

    Science.gov (United States)

    Whalley, Richard D; Walsh, James L

    2016-01-01

    Flowing low temperature atmospheric pressure plasma devices have been used in many technological applications ranging from energy efficient combustion through to wound healing and cancer therapy. The generation of the plasma causes a sudden onset of turbulence in the inhomogeneous axisymmetric jet flow downstream of the plasma plume. The mean turbulent velocity fields are shown to be self-similar and independent of the applied voltage used to generate the plasma. It is proposed that the production of turbulence is related to a combination of the small-amplitude plasma induced body forces and gas heating causing perturbations in the unstable shear layers at the jet exit which grow as they move downstream, creating turbulence. PMID:27561246

  19. Recharge to extensive aquifers by means of atmospheric chloride deposition and ground temperature

    International Nuclear Information System (INIS)

    One of the most uncertain and at the same time essential values for groundwater knowledge and management is aquifer recharge, especially in large areas with scarce data. Under steady state circumstances the atmospheric chloride deposition balance is an effective method to estimate average diffuse recharge and its possible error. Progress in the application are reported to some aquifers, in some of which the water mixtures in groundwater sampling from the aquifer due to recharge spatial variability are considered. Also, recharge affects in ground temperature distribution is considered as an indicator of recharge. Spanish examples from the Iberian Peninsula: Donana, Anoia, the Llobregat delta, and the whole territory are considered, and also from the archipelagos The Canaries: Gran Canaria, Fuerteventura and La Gomera, and the Balearic Islands: Mallorca. (Author) 19 refs.

  20. Solar Atmospheric Magnetic Energy Coupling: Broad Plasma Conditions and Temperature Scales

    CERN Document Server

    Orange, N Brice; Gendre, Bruce; Morris, David C; Oluseyi, Hakeem M

    2016-01-01

    Solar variability investigations that include its magnetic energy coupling are paramount to solving many key solar/stellar physics problems. Particularly understanding the temporal variability of magnetic energy redistribution and heating processes. Using three years of observations from the {\\it Solar Dynamics Observatory's} Atmospheric Imaging Assembly and Heliosemic Magnetic Imager, radiative and magnetic fluxes were measured from coronal hole, quiet Sun, active regions, active region cores (i.e., inter moss), and at full-disk scales, respectively. We present, and mathematically describe, their coupling of radiative fluxes, across broad temperature gradients, to the available photospheric magnetic energy. A comparison of the common linear relationship of radiative to magnetic coupling is performed against our extended broken power-law description, which reveals a potential entanglement of thermodynamic and magnetic energy contributions in existing literature. As such, our work provides an improved approach...

  1. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Jue, E-mail: zhangjue@pku.edu.cn; Fang, Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)

    2015-10-15

    A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.

  2. Laser schlieren deflectometry for temperature analysis of filamentary non-thermal atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, J.; Foest, R.; Reuter, S.; Weltmann, K.-D. [INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Kewitz, T. [Institute of Experimental and Applied Physics, University Kiel, 24098 Kiel (Germany); Sperka, J. [Department of Physical Electronics, Masaryk University, 61137 Brno (Czech Republic)

    2012-10-15

    The heat convection generated by micro filaments of a self-organized non-thermal atmospheric pressure plasma jet in Ar is characterized by employing laser schlieren deflectometry (LSD). It is demonstrated as a proof of principle, that the spatial and temporal changes of the refractive index n in the optical beam path related to the neutral gas temperature of the plasma jet can be monitored and evaluated simultaneously. The refraction of a laser beam in a high gradient field of n(r) with cylindrical symmetry is given for a general real refraction index profile. However, the usually applied Abel approach represents an ill-posed problem and in particular for this plasma configuration. A simple analytical model is proposed in order to minimize the statistical error. Based on that, the temperature profile, specifically the absolute temperature in the filament core, the FWHM, and the frequencies of the collective filament dynamics are obtained for non-stationary conditions. For a gas temperature of 700 K inside the filament, the presented model predicts maximum deflection angles of the laser beam of 0.3 mrad which is in accordance to the experimental results obtained with LSD. Furthermore, the experimentally obtained FWHM of the temperature profile produced by the filament at the end of capillary is (1.5 {+-} 0.2) mm, which is about 10 times wider than the visual radius of the filament. The obtained maximum temperature in the effluent is (450 {+-} 30) K and is in consistence with results of other techniques. The study demonstrates that LSD represents a useful low-cost method for monitoring the spatiotemporal behaviour of microdischarges and allows to uncover their dynamic characteristics, e.g., the temperature profile even for challenging diagnostic conditions such as moving thin discharge filaments. The method is not restricted to the miniaturized and self-organized plasma studied here. Instead, it can be readily applied to other configurations that produce measurable

  3. Laser schlieren deflectometry for temperature analysis of filamentary non-thermal atmospheric pressure plasma

    Science.gov (United States)

    Schäfer, J.; Foest, R.; Reuter, S.; Kewitz, T.; Šperka, J.; Weltmann, K.-D.

    2012-10-01

    The heat convection generated by micro filaments of a self-organized non-thermal atmospheric pressure plasma jet in Ar is characterized by employing laser schlieren deflectometry (LSD). It is demonstrated as a proof of principle, that the spatial and temporal changes of the refractive index n in the optical beam path related to the neutral gas temperature of the plasma jet can be monitored and evaluated simultaneously. The refraction of a laser beam in a high gradient field of n(r) with cylindrical symmetry is given for a general real refraction index profile. However, the usually applied Abel approach represents an ill-posed problem and in particular for this plasma configuration. A simple analytical model is proposed in order to minimize the statistical error. Based on that, the temperature profile, specifically the absolute temperature in the filament core, the FWHM, and the frequencies of the collective filament dynamics are obtained for non-stationary conditions. For a gas temperature of 700 K inside the filament, the presented model predicts maximum deflection angles of the laser beam of 0.3 mrad which is in accordance to the experimental results obtained with LSD. Furthermore, the experimentally obtained FWHM of the temperature profile produced by the filament at the end of capillary is (1.5 ± 0.2) mm, which is about 10 times wider than the visual radius of the filament. The obtained maximum temperature in the effluent is (450 ± 30) K and is in consistence with results of other techniques. The study demonstrates that LSD represents a useful low-cost method for monitoring the spatiotemporal behaviour of microdischarges and allows to uncover their dynamic characteristics, e.g., the temperature profile even for challenging diagnostic conditions such as moving thin discharge filaments. The method is not restricted to the miniaturized and self-organized plasma studied here. Instead, it can be readily applied to other configurations that produce measurable

  4. Optimal adjustment of the atmospheric forcing parameters of ocean models using sea surface temperature data assimilation

    Directory of Open Access Journals (Sweden)

    M. Meinvielle

    2013-10-01

    Full Text Available In ocean general circulation models, near-surface atmospheric variables used to specify the atmospheric boundary condition remain one of the main sources of error. The objective of this research is to constrain the surface forcing function of an ocean model by sea surface temperature (SST data assimilation. For that purpose, a set of corrections for ERAinterim (hereafter ERAi reanalysis data is estimated for the period of 1989–2007, using a sequential assimilation method, with ensemble experiments to evaluate the impact of uncertain atmospheric forcing on the ocean state. The control vector of the assimilation method is extended to atmospheric variables to obtain monthly mean parameter corrections by assimilating monthly SST and sea surface salinity (SSS climatological data in a low resolution global configuration of the NEMO model. In this context, the careful determination of the prior probability distribution of the parameters is an important matter. This paper demonstrates the importance of isolating the impact of forcing errors in the model to perform relevant ensemble experiments. The results obtained for every month of the period between 1989 and 2007 show that the estimated parameters produce the same kind of impact on the SST as the analysis itself. The objective is then to evaluate the long-term time series of the forcing parameters focusing on trends and mean error corrections of air–sea fluxes. Our corrections tend to equilibrate the net heat-flux balance at the global scale (highly positive in ERAi database, and to remove the potentially unrealistic negative trend (leading to ocean cooling in the ERAi net heat flux over the whole time period. More specifically in the intertropical band, we reduce the warm bias of ERAi data by mostly modifying the latent heat flux by wind speed intensification. Consistently, when used to force the model, the corrected parameters lead to a better agreement between the mean SST produced by the

  5. Retrieving Atmospheric Temperature Profiles from AMSU-A Data with Neural Networks

    Institute of Scientific and Technical Information of China (English)

    YAO Zhigang; CHEN Hongbin; LIN Longfu

    2005-01-01

    Back propagation neural networks are used to retrieve atmospheric temperature profiles from NOAA-16 Advanced Microwave Sounding Unit-A (AMSU-A) measurements over East Asia. The collocated radiosonde observation and AMSU-A data over land in 2002-2003 are used to train the network, and the data over land in 2004 are used to test the network. A comparison with the multi-linear regression method shows that the neural network retrieval method can significantly improve the results in all weather conditions.When an offset of 0.5 K or a noise level of +0.2 K is added to all channels simultaneously, the increase in the overall root mean square (RMS) error is less than 0.1 K. Furthermore, an experiment is conducted to investigate the effects of the window channels on the retrieval. The results indicate that the brightness temperatures of window channels can provide significantly useful information on the temperature retrieval near the surface. Additionally, the RMS errors of the profiles retrieved with the trained neural network are compared with the errors from the International Advanced TOVS (ATOVS) Processing Package (IAPP).It is shown that the network-based algorithm can provide much better results in the experiment region and comparable results in other regions. It is also noted that the network can yield remarkably better results than IAPP at the low levels and at about the 250-hPa level in summer skies over ocean. Finally,the network-based retrieval algorithm developed herein is applied in retrieving the temperature anomalies of Typhoon Rananim from AMSU-A data.

  6. The Temperature of the Dimethylhydrazine Drops Moving in the Atmosphere after Depressurization of the Fuel Tank Rockets

    Directory of Open Access Journals (Sweden)

    Bulba Elena

    2016-01-01

    Full Text Available This work includes the results of the numerical modeling of temperature changes process of the dimethylhydrazine (DMH drops, taking into account the radial temperature gradient in the air after the depressurization of the fuel compartments rockets at high altitude. There is formulated a mathematical model describing the process of DMH drops thermal state modifying when it's moving to the Earth's surface. There is the evaluation of the influence of the characteristic size of heptyl drops on the temperature distribution. It's established that the temperatures of the small size droplets practically completely coincide with the distribution of temperature in the atmosphere at altitudes of up to 40 kilometers.

  7. Effect of irradiation and modified atmosphere packaging on the microbiological and sensory quality of pork stored at refrigeration temperatures

    International Nuclear Information System (INIS)

    The effect of combining low-dose irradiation (1.75 kGy) with modified atmosphere packaging (MAP) on the microbiological and sensory quality of pork chops stored at refrigeration temperatures was studied. The microflora of irradiated MAP pork was almost exclusively composed of lactic acid bacteria, predominantly Lactobacillus spp. Modified atmospheres containing either 25 or 50% CO2, balance N2, resulted in the best microbial control in irradiated pork held at 4°C, compared to an unirradiated MAP control, and these atmospheres were subsequently used in sensory studies. The atmosphere containing 25% CO2 75% N2 maintained the uncooked colour and odour of irradiated pork chops more effectively than 50% CO2 50% N2. Therefore packaging in a modified atmosphere containing 25% CO2, balance N2, followed by irradiation to a dose of 1.75 kGy is recommended to improve the microbiological and sensory quality of pork chops

  8. Physiological and phytochemical quality of ready-to-eat rocket leaves as affected by processing, modified atmosphere and storage temperature

    OpenAIRE

    Amaro, Ana Luísa; Pereira, Maria João; Carvalho, Susana; Vasconcelos, Marta; Pintado, Maria Manuela

    2014-01-01

    Rocket leaves are widely consumed as a ready-to-eat (RTE) leafy vegetable, valued by its wide range of health promoting phytonutrients, including vitamin C and phenolic compounds. Processing and storage conditions are known to affect quality of RTE rocket leaves, with package atmosphere and low temperature as key factors in quality maintenance throughout processing to consumption. However, information on rocket leaves nutritional quality as affected by modified atmosphere and storage...

  9. Synthesis of porous superparamagnetic iron oxides from colloidal nanoparticles: Effect of calcination temperature and atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Wei; Xu, Jing; Ding, Wei; Wang, Yajie; Zheng, Wenping; Wu, Feng; Li, Jinjun, E-mail: ljjcbacademy@163.com

    2015-03-01

    Nanostructured iron oxides with superparamagnetism were synthesized from colloidal particles of hydrous iron oxide. The synthesis procedure involved preparation of acetone-nanoparticle composite and calcination of the composite in air or nitrogen. The effects of calcination temperature and atmosphere on the properties of the products were investigated. Powder X-ray diffraction, {sup 57}Fe Mössbauer spectra, transmission electron microscopy, nitrogen sorption, thermal analysis and vibrating-sample magnetometry were applied to characterize the materials. The products calcined in flowing air are composed of nanoparticles, while those calcined in flowing nitrogen contain nanosheets. The former has larger specific surface areas, whereas the latter has stronger saturation magnetization in external magnetic field. Increasing calcination temperature reduced the specific surface area of the product, whereas enhanced its saturation magnetization. Furthermore, the iron oxides with superparamagnetism showed good affinity to arsenite, and therefore they could be potential adsorbents for arsenic remediation in water. - Highlights: • Nanostructured superparamagnetic iron oxides were synthesized from colloidal nanoparticles. • Calcination in air led to formation of nanoparticles. • Calcination in nitrogen led to formation of nanosheets. • The superparamagnetic materials had high adsorption capabilities for arsenite.

  10. High Temperature Behavior of Oxidized Mild Steel in Dry and Wet Atmospheres

    International Nuclear Information System (INIS)

    During the hot rolling process, steels develop an oxide scale on their surface. This scale can affect the mechanical properties of the rolled steel and its surface aspect. The main problem comes from the mechanical integrity of the oxide scales which could delaminate or crack, leading eventually to later oxide incrustation within the steel. The objective of the present work is to qualify the mechanical integrity of the iron oxide scales during the hot rolling process. The laboratory experiments use a four point bending test to simulate the mechanical solicitation which takes place during the rolling sequence of the steel slabs. The oxide scales grow on a mild steel at 900 .deg. C under wet or dry atmosphere and the oxidized steel is then mechanically tested at 900 .deg. C or 700 .deg. C. The high temperature four point bending tests are completed with microstructural observations and with the record of acoustic emission to follow in-situ the mechanical damages of the oxide scales. The results show the role of water vapor which promotes the scale adherence, and the role of the temperature as the oxide are more damaged at 700 .deg. C than at 900 .deg. C

  11. Interpretation of biomass gasification yields regarding temperature intervals under nitrogen-steam atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Haykiri-Acma, H.; Yaman, S. [Istanbul Technical University, Chemical and Metallurgical Engineering Faculty, Chemical Engineering Department, 34469 Maslak, Istanbul (Turkey)

    2007-04-15

    Gasification of some agricultural waste biomass samples (sunflower shell, pine cone, cotton refuse, and olive refuse) and colza seed was performed using a thermogravimetric analyzer at temperatures up to 1273 K with a constant heating rate of 20 K/min under a dynamic nitrogen-steam atmosphere. Derivative thermogravimetric analysis profiles of the samples were derived from the non-isothermal thermogravimetric analysis data. Gasification yields of the biomass samples at temperature intervals of 473-553 K, 553-653 K, 653-773 K, 773-973 K, and 973-1173 K were investigated considering the successive stages of ''evolution of carbon oxides'', ''start of hydrocarbon evolution'', ''evolution of hydrocarbons'', ''dissociation'', and ''evolution of hydrogen'', respectively. Although, there were some interactions between these stages, some evident relations were observed between the gasification yields in a given stage and the chemical properties of the parent biomass materials. (author)

  12. Response of leaf litter decomposition to rises in atmospheric CO2 and temperature

    Science.gov (United States)

    Hammrich, A.; Flury, S.; Gessner, M. O.

    2007-05-01

    Atmospheric concentrations of CO2 have considerably increased in the last century and are expected to rise further. Elevated CO2 concentrations not only increase global temperature but also have potential to change plant litter quality, for example by increasing lignin content, changing C:N ratios and altering tannin contents. These chemical changes may interact with increased temperature to alter litter decomposition. To test whether changes in litter quality and warming affect decomposition, we conducted a field experiment with leaf litter collected from six species of mature deciduous trees exposed to either ambient or elevated CO2 levels. We used a set of 16 enclosures installed in four blocks in a freshwater marsh in a prealpine lake to test for the effects of CO2-mediated litter quality and temperature and the interaction of both factors. We measured leaf mass loss of the twelve litter types in control and heated enclosures (4 °C above ambient) and also in the open marsh. In contrast to expectations, species decomposing at low (oak and beech) and medium (hornbeam and maple) rates showed faster mass loss when leaves were grown under elevated CO2 conditions, whereas fast-decomposing species (cherry and basswood) showed no clear response. The accelerated decomposition of CO2-enriched litter could be due to higher amounts of nonstructural carbohydrates, which may have been either leached or readily degraded. Warming had a surprisingly small influence on mass loss of the tested litter species, and interactive effects were weak. These results suggest that direct and indirect effects of elevated CO2 levels on litter decomposition may not be readily predictable from first principles.

  13. Simulation of atmospheric temperature inversions over greater cairo using the MM5 Meso-Scale atmospheric model

    International Nuclear Information System (INIS)

    Air pollution episodes have been recorded in Cairo, during the fall season, since 1999, as a result of specific meteorological conditions combined with large quantity of pollutants created by several ground-based sources. The main reason for the smog-like episodes (black clouds) is adverse weather conditions with low and variable winds, high humidity and strong temperature inversions in the few-hundred meters above the ground. The two important types of temperature inversion affecting the air pollution are surface or ground (radiation) inversion and subsidence (elevated) inversion. The surface temperature inversion is associated with a rapid decrease in the ground surface temperature with the simultaneous existence of warm air in the lower troposphere. The inversion develops at dusk and continues until the surface warms again the following day. Pollutants emitted during the night are caught under this inversion lid.Subsidence inversion forms when warm air masses move over colder air masses. The inversion develops with a stagnating high-pressure system (generally associated with fair weather). Under these conditions, the pressure gradient becomes progressively weaker so that winds become light. These light winds greatly reduce the horizontal transport and dispersion of pollutants. At the same time, the subsidence inversion acts as a barrier to the vertical dispersion of the pollutants. In this study, the Penn State/NCAR meso -scale model (MM5) is used to simulate the temperature inversion phenomenon over Greater Cairo region during the fall season of 2004. Accurate computations of the heat transfer at the surface are needed to capture this phenomenon. This can only be achieved by high-resolution simulations in both horizontal and vertical directions. Hence, for accurate simulation of the temperature inversion over Greater Cairo, four nested domains of resolutions of 27 km, 9 km, 3 km and 1 km, respectively, were used in the horizontal planes. Furthermore, 42 levels

  14. Spatial and Temporal Dependence of Temperature Variations Induced by Atmospheric Pressure Variations in Shallow Underground Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Perrier, F.; Le Mouel, J.L. [Inst Phys Globe, Equipe Geomagnetisme, F-75005 Paris (France); Univ Paris Diderot, UMR7154, F-75005 Paris (France); Richon, P. [CEA Bruyeres-le-Chatel, DIF, 91 (France); Richon, P. [Inst Phys Globe, Equipe Geol Syst Volcan, UMR7154, F-75005 Paris (France)

    2010-07-01

    Pressure-induced temperature (PIT) variations are systematically observed in the atmosphere of underground cavities. Such PIT variations are due to the compressibility of the air, damped by heat exchange with the rock surface. It is important to characterize such processes for numerous applications, such as the preservation of painted caves or the assessment of the long-term stability of underground laboratories and underground waste repositories. In this paper we thoroughly study the spatio-temporal dependence of the PIT response versus frequency using vertical and horizontal profiles of temperature installed in an abandoned underground quarry located in Vincennes, near Paris. The PIT response varies from about 20 * 10{sup -3} C hPa{sup -1} at a frequency of 2 * 10{sup -4} Hz to 2-3 * 10{sup -3} C hPa{sup -1} at a frequency of one cycle per day. An analytical expression based on a simple heat exchange model accounts for the observed features of the PIT response and allows for correcting the measured time series, having standard deviations of about 10{sup -2} C, to residual variations with a standard deviation of about 2 * 10{sup -3} C. However, a frequency-dependent attenuation of the response, corresponding to a reduction in amplitude with a factor varying from 2 to 3, is observed near the walls. This effect is not included in the simple analytical expression, but it can be accounted for by a one-dimensional differential equation, solved numerically, where temperature variations in the atmosphere are damped by an effective radiative coupling with the rock surface, complemented by a diffusive coupling near the walls. The TIP response is observed to remain stable over several years, but a large transient enhancement of about a factor of two is observed near the roof at one location from July to October 2005. In a cavity located below the Paris Observatory, an additional contribution is identified in the PIT response function versus frequency for frequencies smaller

  15. Characterizations of atmospheric pressure low temperature plasma jets and their applications

    Science.gov (United States)

    Karakas, Erdinc

    2011-12-01

    Atmospheric pressure low temperature plasma jets (APLTPJs) driven by short pulses have recently received great attention because of their potential in biomedical and environmental applications. This potential is due to their user-friendly features, such as low temperature, low risk of arcing, operation at atmospheric pressure, easy handheld operation, and low concentration of ozone generation. Recent experimental observations indicate that an ionization wave exists and propagates along the plasma jet. The plasma jet created by this ionization wave is not a continuous medium but rather consists of a bullet-like-structure known as "Plasma Bullet". More interestingly, these plasma bullets actually have a donut-shaped makeup. The nature of the plasma bullet is especially interesting because it propagates in the ambient air at supersonic velocities without any externally applied electric field. In this dissertation, experimental insights are reported regarding the physical and chemical characteristics of the APLTPJs. The dynamics of the plasma bullet are investigated by means of a high-speed ICCD camera. A plasma bullet propagation model based on the streamer theory is confirmed with adequate explanations. It is also found that a secondary discharge, ignited by the charge accumulation on the dielectric electrode surfaces at the end of the applied voltage, interrupts the plasma bullet propagation due to an opposing current along the ionization channel. The reason for this interesting phenomenon is explained in detail. The plasma bullet comes to an end when the helium mole fraction along the ionization channel, or applied voltage, or both, are less than some critical values. The presence of an inert gas channel in the surrounding air, such as helium or argon, has a critical role in plasma bullet formation and propagation. For this reason, a fluid dynamics study is employed by a commercially available simulation software, COMSOL, based on finite element method. Spatio

  16. Wind and Temperature Spectrometry of the Upper Atmosphere in Low-Earth Orbit

    Science.gov (United States)

    Herrero, Federico

    2011-01-01

    Wind and Temperature Spectrometry (WATS) is a new approach to measure the full wind vector, temperature, and relative densities of major neutral species in the Earth's thermosphere. The method uses an energy-angle spectrometer moving through the tenuous upper atmosphere to measure directly the angular and energy distributions of the air stream that enters the spectrometer. The angular distribution gives the direction of the total velocity of the air entering the spectrometer, and the energy distribution gives the magnitude of the total velocity. The wind velocity vector is uniquely determined since the measured total velocity depends on the wind vector and the orbiting velocity vector. The orbiting spectrometer moves supersonically, Mach 8 or greater, through the air and must point within a few degrees of its orbital velocity vector (the ram direction). Pointing knowledge is critical; for example, pointing errors 0.1 lead to errors of about 10 m/s in the wind. The WATS method may also be applied without modification to measure the ion-drift vector, ion temperature, and relative ion densities of major ionic species in the ionosphere. In such an application it may be called IDTS: Ion-Drift Temperature Spectrometry. A spectrometer-based coordinate system with one axis instantaneously pointing along the ram direction makes it possible to transform the Maxwellian velocity distribution of the air molecules to a Maxwellian energy-angle distribution for the molecular flux entering the spectrometer. This implementation of WATS is called the gas kinetic method (GKM) because it is applied to the case of the Maxwellian distribution. The WATS method follows from the recognition that in a supersonic platform moving at 8,000 m/s, the measurement of small wind velocities in the air on the order of a few 100 m/s and less requires precise knowledge of the angle of incidence of the neutral atoms and molecules. The same is true for the case of ion-drift measurements. WATS also

  17. Analysis of the correlations between atmospheric boundary-layer and free-tropospheric temperatures in the tropics

    Science.gov (United States)

    Wu, Wei; Dessler, Andrew E.; North, Gerald R.

    2006-10-01

    We investigate the vertical correlations between temperature variations at 925 hPa, in the atmospheric boundary layer, and temperature variations in the free troposphere and lower stratosphere in the Tropics in daily and monthly averaged satellite and radiosonde measurements and in six General Circulation Models (GCMs). The results show generally positive correlations between the boundary layer temperatures and temperatures in the rest of the troposphere, with negative correlations occurring around the tropopause and in the lower stratosphere. In typically non-convective regions, the variations at the surface show little connection to mid and upper tropospheric temperature variations. In the convective Western Pacific, the correlations are low in the mid troposphere and much larger around 200 hPa. GCMs generally capture the temperature correlations, although as a group they tend to overpredict the coupling between the boundary layer and the rest of the troposphere. The basic correlation patterns of monthly temperature are found similar to the daily results.

  18. Modeling of atmospheric corrosion of metals and its acceleration by increasing temperature in chambers of artificial climate

    International Nuclear Information System (INIS)

    Data are given on studying the effect of temperature on the rates of iron, zinc, cadmium, and copper corrosion in a pure humid atmosphere and in the presence of a thin phase water layer on the metal. The coefficients of corrosion acceleration with temperature have been determined. By conducting the experiments in chambers with artificial climate at 40-60 deg C, it has been shown how the corrosion process can be accelerated on the metals investigated in comparison with real conditions

  19. An atmospheric general circulation model for Pluto with predictions for New Horizons temperature profiles

    Science.gov (United States)

    Zalucha, Angela M.

    2016-06-01

    Results are presented from a 3D Pluto general circulation model (GCM) that includes conductive heating and cooling, non-local thermodynamic equilibrium (non-LTE) heating by methane at 2.3 and 3.3 μm, non-LTE cooling by cooling by methane at 7.6 μm, and LTE CO rotational line cooling. The GCM also includes a treatment of the subsurface temperature and surface-atmosphere mass exchange. An initially 1 m thick layer of surface nitrogen frost was assumed such that it was large enough to act as a large heat sink (compared with the solar heating term) but small enough that the water ice subsurface properties were also significant. Structure was found in all three directions of the 3D wind field (with a maximum magnitude of the order of 10 m s-1 in the horizontal directions and 10-5 microbar s-1 in the vertical direction). Prograde jets were found at several altitudes. The direction of flow over the poles was found to very with altitude. Broad regions of up-welling and down-welling were also found. Predictions of vertical temperature profiles are provided for the Alice and Radio science Experiment instruments on New Horizons, while predictions of light curves are provided for ground-based stellar occultation observations. With this model methane concentrations of 0.2 per cent and 1.0 per cent and 8 and 24 microbar surface pressures are distinguishable. For ground-based stellar occultations, a detectable difference exists between light curves with the different methane concentrations, but not for different initial global mean surface pressures.

  20. The signatures of large-scale patterns of atmospheric variability in Antarctic surface temperatures

    Science.gov (United States)

    Marshall, Gareth J.; Thompson, David W. J.

    2016-04-01

    We investigate the impact that the four principal large-scale patterns of Southern Hemisphere (SH) atmospheric circulation variability have on Antarctic surface air temperature (SAT): (1) the southern baroclinic annular mode (BAM), which is associated with variations in extratropical storm amplitude; (2) the Southern Annular Mode (SAM), associated with latitudinal shifts in the midlatitude jet; and (3) the two Pacific-South American patterns (PSA1 and PSA2), which are characterized by wave trains originating in the tropical Pacific that extend across the SH extratropics. A key aspect is the use of 35 years of daily observations and reanalysis data, which affords a sufficiently large sample size to assess the signatures of the circulation patterns in both the mean and variability of daily mean SAT anomalies. The BAM exerts the weakest influence on Antarctic SAT, albeit it is still important over select regions. Consistent with previous studies, the SAM is shown to influence SAT across most of the continent throughout the year. The PSA1 also affects SAT across almost all of Antarctica. Regionally, both PSA patterns can exert a greater impact on SAT than the SAM but also have a significantly weaker influence during summer, reflecting the seasonality of the SH response to El Niño-Southern Oscillation. The SAM and PSA patterns have distinct signatures in daily SAT variance that are physically consistent with their signatures in extratropical dynamic variability. The broad-scale climate linkages identified here provide benchmarks for interpreting the Antarctic climate response to future changes in tropical sea surface temperatures, ozone recovery, and greenhouse gas increases.

  1. Characteristics of SAO and AO in equatorial middle atmospheric temperature pattern

    International Nuclear Information System (INIS)

    Complete text of publication follows. More than 10 years (1998-2008) of data from a low latitude station, Gadanki, India (13.5deg N, 79.2deg E), has been utilized to measure middle atmospheric temperature pattern, using lidar and TIMED/SABER, which exhibits the presence of semi-annual oscillation (SAO) and annual oscillation (AO). AO component is stronger in mesospheric region (80-90 km) and SAO is dominant at stratospheric altitudes (30-50 km). Overall, AO possesses higher amplitude ∼ 6 K, and SAO shows relatively less amplitude ∼ 1-2 K. AO at 90 km, has its crest around summer solstice, and the same at 80 shows peak around winter solstice with a downward progression speed ∼ 1.67 km/month. SAO propagates downward with an average phase speed ∼ 7 km/month and its phase maximizes around equinox and solstice at 50 and 30 km, respectively. Observed SAO has also shown seasonal asymmetry in the peak.

  2. Observation of semiannual and annual oscillation in equatorial middle atmospheric long term temperature pattern

    Energy Technology Data Exchange (ETDEWEB)

    Guharay, A.; Pant, P. [Aryabhatta Research Institute of observational scienES (ARIES), Nainital (India); Nath, D. [National Atmospheric Research Lab. (NARL), Gadanki (India); Pande, B.; Pandey, K. [Kumaun Univ., Nainital (India). Dept. of Physics; Russell, J.M. III [Hampton Univ., Hampton, VA (United States). Center for Atmospheric Sciences

    2009-07-01

    Extensive measurement of middle atmospheric temperature with the help of lidar data of more than 10 years (1998-2008) and TIMED/SABER data of 7 years (2002-2008), has been carried out from a low latitude station, Gadanki, India (13.5 N, 79.2 E), which exhibits the presence of semiannual oscillation (SAO) and annual oscillation (AnO). The AnO component is stronger in the mesospheric region (80-90 km) and the SAO is dominant at stratospheric altitudes (30-50 km). Overall, the AnO possesses higher amplitude {proportional_to}6-7 K, and the SAO shows less amplitude {proportional_to}1-2 K. The AnO present at 90 km finds crest near summer solstice, and the same at 80 km shows peak near winter solstice with a downward progression speed {proportional_to}1.7 km/month. The SAO propagates downward with an average phase speed {proportional_to}9 km/month and phase maximizes around equinox and solstice at 50 and 30 km, respectively. The observed SAO has also shown seasonal asymmetry in peaks. (orig.)

  3. Observation of semiannual and annual oscillation in equatorial middle atmospheric long term temperature pattern

    Directory of Open Access Journals (Sweden)

    A. Guharay

    2009-11-01

    Full Text Available Extensive measurement of middle atmospheric temperature with the help of lidar data of more than 10 years (1998–2008 and TIMED/SABER data of 7 years (2002–2008, has been carried out from a low latitude station, Gadanki, India (13.5° N, 79.2° E, which exhibits the presence of semiannual oscillation (SAO and annual oscillation (AnO. The AnO component is stronger in the mesospheric region (80–90 km and the SAO is dominant at stratospheric altitudes (30–50 km. Overall, the AnO possesses higher amplitude ~6–7 K, and the SAO shows less amplitude ~1–2 K. The AnO present at 90 km finds crest near summer solstice, and the same at 80 km shows peak near winter solstice with a downward progression speed ~1.7 km/month. The SAO propagates downward with an average phase speed ~9 km/month and phase maximizes around equinox and solstice at 50 and 30 km, respectively. The observed SAO has also shown seasonal asymmetry in peaks.

  4. Temperature Dependence of Nitro-Quenching by Atmospheric-Pressure Plasma

    Science.gov (United States)

    Mitani, Masaki; Ichiki, Ryuta; Iwakiri, Yutaro; Akamine, Shuichi; Kanazawa, Seiji

    2015-09-01

    A lot of techniques exist as the hardening method of steels, such as nitriding, carburizing and quenching. However, low-alloy steels cannot be hardened by nitriding because hardening by nitriding requires nitride precipitates of special alloy elements such as rare metals. Recently, nitro-quenching (NQ) was developed as a new hardening process, where nitrogen invokes martensitic transformation instead of carbon. NQ is adaptable to hardening low-alloy steels because it does not require alloy elements. In industrial NQ, nitrogen diffusion into steel surface is operated in high temperature ammonia gas. As a new technology, we have developed surface hardening of low-alloy steel by NQ using an atmospheric-pressure plasma. Here the pulsed-arc plasma jet with nitrogen/hydrogen gas mixture is sprayed onto steel surface and then water quench the sample. As a result, the surface of low-alloy steel was partially hardened up to 800 Hv by producing iron-nitrogen martensite. However, the hardness profile is considerably non-uniform. We found that the non-uniform hardness profile can be controlled by changing the treatment gap, the gap between the jet nozzle and the sample surface. Eventually, we succeeded in hardening a targeted part of steel by optimizing the treatment gap. Moreover, we propose the mechanism of non-uniform hardness.

  5. Retrieval of structure functions of air temperature and refractive index from large eddy simulations of the atmospheric boundary layer

    NARCIS (Netherlands)

    Wilson, C.; Eijk, A.M.J. van; Fedorovich, E.

    2013-01-01

    A methodology is presented to infer the refractive-index structure function parameter and the structure parameters for temperature and humidity from numerical simulations of the turbulent atmospheric convective boundary layer (CBL). The method employs spatial and temporal averaging of multiple reali

  6. Growth behavior prediction of fresh catfish fillet with Pseudomonas aeruginosa under stresses of allyl isothiocyanate, temperature and modified atmosphere

    Science.gov (United States)

    Pseudomonas aeruginosa, a common spoilage microorganism in fish, grows rapidly when temperature rises above 4 degree C. The combination of allyl isothiocyanate (AIT) and modified atmosphere (MA) was applied and proved to be effective to retard the growth of P. aeruginosa. The objective of this resea...

  7. Variability of the Structure Parameters of Temperature and Humidity Observed in the Atmospheric Surface Layer Under Unstable Conditions

    NARCIS (Netherlands)

    Braam, M.; Moene, A.F.; Beyrich, F.

    2014-01-01

    The structure parameters of temperature and humidity are important in scintillometry as they determine the structure parameter of the refractive index of air, the primary atmospheric variable obtained with scintillometers. In this study, we investigate the variability of the logarithm of the Monin-O

  8. A new procedure for estimating the cell temperature of a high concentrator photovoltaic grid connected system based on atmospheric parameters

    International Nuclear Information System (INIS)

    Highlights: • Concentrating grid-connected systems are working at maximum power point. • The operating cell temperature is inherently lower than at open circuit. • Two novel methods for estimating the cell temperature are proposed. • Both predict the operating cell temperature from atmospheric parameters. • Experimental results show that both methods perform effectively. - Abstract: The working cell temperature of high concentrator photovoltaic systems is a crucial parameter when analysing their performance and reliability. At the same time, due to the special features of this technology, the direct measurement of the cell temperature is very complex and is usually obtained by using different indirect methods. High concentrator photovoltaic modules in a system are operating at maximum power since they are connected to an inverter. So that, their cell temperature is lower than the cell temperature of a module at open-circuit voltage since an important part of the light power density is converted into electricity. In this paper, a procedure for indirectly estimating the cell temperature of a high concentrator photovoltaic system from atmospheric parameters is addressed. Therefore, this new procedure has the advantage that is valid for estimating the cell temperature of a system at any location of interest if the atmospheric parameters are available. To achieve this goal, two different methods are proposed: one based on simple mathematical relationships and another based on artificial intelligent techniques. Results show that both methods predicts the cell temperature of a module connected to an inverter with a low margin of error with a normalised root mean square error lower or equal than 3.3%, an absolute root mean square error lower or equal than 2 °C, a mean absolute error lower or equal then 1.5 °C, and a mean bias error and a mean relative error almost equal to 0%

  9. Mid-to-late Holocene temperature evolution and atmospheric dynamics over Europe in regional model simulations

    Science.gov (United States)

    Russo, Emmanuele; Cubasch, Ulrich

    2016-08-01

    The improvement in resolution of climate models has always been mentioned as one of the most important factors when investigating past climatic conditions, especially in order to evaluate and compare the results against proxy data. Despite this, only a few studies have tried to directly estimate the possible advantages of highly resolved simulations for the study of past climate change. Motivated by such considerations, in this paper we present a set of high-resolution simulations for different time slices of the mid-to-late Holocene performed over Europe using the state-of-the-art regional climate model COSMO-CLM. After proposing and testing a model configuration suitable for paleoclimate applications, the aforementioned mid-to-late Holocene simulations are compared against a new pollen-based climate reconstruction data set, covering almost all of Europe, with two main objectives: testing the advantages of high-resolution simulations for paleoclimatic applications, and investigating the response of temperature to variations in the seasonal cycle of insolation during the mid-to-late Holocene. With the aim of giving physically plausible interpretations of the mismatches between model and reconstructions, possible uncertainties of the pollen-based reconstructions are taken into consideration. Focusing our analysis on near-surface temperature, we can demonstrate that concrete advantages arise in the use of highly resolved data for the comparison against proxy-reconstructions and the investigation of past climate change. Additionally, our results reinforce previous findings showing that summertime temperatures during the mid-to-late Holocene were driven mainly by changes in insolation and that the model is too sensitive to such changes over Southern Europe, resulting in drier and warmer conditions. However, in winter, the model does not correctly reproduce the same amplitude of changes evident in the reconstructions, even if it captures the main pattern of the pollen

  10. The atmospheric muon flux in correlation with temperature variations in the low stratosphere (50-200 mb).

    Science.gov (United States)

    Bertaina, M.; Briatore, L.; Longhetto, A.; Navarra, G.; EAS-TOP collaboraiton

    The dependence of the muon flux from the atmospheric parameters (pressure and temperature) is a well known effect since long time ago, that is usually corrected for in cosmic ray measurements. We have correlated at EAS-TOP (LNGS) the muon flux detected by the EMD detector (29 stations, 10m2 each, E_thr>3MeV) with the atmospheric temperature (10-1000mb levels) monitored by the radio-soundings of the Aeronautica Militare at Pratica di Mare (Rome). A significant effect has been observed when the muon flux is correlated with the atmospheric temperature in the region 50-200mb (50-200gr/cm2), as expected, since this is the region where the mesons of first generation are produced. The effect becomes even larger (K_T=-9.5+/-1.1)x10-4 K-1) when the variations of the cosmic ray primary flux is taken into account (Neutron Monitor, Rome). Then, the technique has been used to monitor strong temperature variations in the low stratosphere through the muon flux in two periods, showing that the average temperature variations in the low stratosphere are reproduced with a ~2K uncertainty. The main results of this analysis will be presented.

  11. Online diagnosis of electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure by optical emission spectra

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Methane coupling under low temperature plasmas at atmospheric pressure is a green process by use of renewable sources of energy. In this study, CH4+H2 dis- charge plasma was on-line diagnosed by optical emission spectra so as to char- acterize the discharge system and to do spade work for the optimization of the technical parameters for future commercial production of methane coupling under plasmas. The study was focused on a calculation method for the online diagnosis of the electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure. The diagnostic method is easy, efficient and fairly precise. A serious er- ror in a literature was corrected during the reasoning of its series of equations formerly used to calculate electron temperatures in plasmas.

  12. Temperature rise in objects due to optical focused beam through atmospheric turbulence near ground and ocean surface

    Science.gov (United States)

    Stoneback, Matthew; Ishimaru, Akira; Reinhardt, Colin; Kuga, Yasuo

    2013-03-01

    We consider an optical beam propagated through the atmosphere and incident on an object causing a temperature rise. In clear air, the physical characteristics of the optical beam transmitted to the object surface are influenced primarily by the effect of atmospheric turbulence, which can be significant near the ground or ocean surface. We use a statistical model to quantify the expected power transfer through turbulent atmosphere and provide guidance toward the threshold of thermal blooming for the considered scenarios. The bulk thermal characteristics of the materials considered are used in a thermal diffusion model to determine the net temperature rise at the object surface due to the incident optical beam. These results of the study are presented in graphical form and are of particular interest to operators of high power laser systems operating over large distances through the atmosphere. Numerical examples include a CO2 laser (λ=10.6 μm) with: aperture size of 5 cm, varied pulse duration, and propagation distance of 0.5 km incident on 0.1-mm copper, 10-mm polyimide, 1-mm water, and 10-mm glass/resin composite targets. To assess the effect of near ground/ocean laser propagation, we compare turbulent (of varying degrees) and nonturbulent atmosphere.

  13. The Titan Haze Simulation experiment: laboratory simulation of Titan's atmospheric chemistry at low temperature

    Science.gov (United States)

    Sciamma-O'Brien, E.; Contreras, C. S.; Ricketts, C. L.; Salama, F.

    2012-04-01

    In Titan’s atmosphere, a complex organic chemistry between its two main constituents, N2 and CH4, leads to the production of heavy molecules and subsequently to solid organic aerosols. Several instruments onboard Cassini have detected neutral, positively and negatively charged particles and heavy molecules in the ionosphere of Titan[1,2]. In particular, the presence of benzene (C6H6) and toluene (C6H5CH3)[3], which are critical precursors of polycyclic aromatic hydrocarbon (PAH) compounds, suggests that PAHs might play a role in the production of Titan’s aerosols. The Titan Haze Simulation (THS) experiment has been developed at NASA Ames’ Cosmic Simulation facility (COSmIC) to study the chemical pathways that link the simple precursor molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN…) to benzene, and to PAHs and nitrogen-containing PAHs (or PANHs) as precursors to the production of solid aerosols. In the THS experiment, Titan’s atmospheric chemistry is simulated by plasma in the stream of a supersonic jet expansion. With this unique design, the gas mixture is cooled to Titan-like temperature (~150K) before inducing the chemistry by plasma discharge. Different gas mixtures containing the first products of Titan’s N2-CH4 chemistry but also much heavier molecules like PAHs or PANHs can be injected to study specific chemical reactions. The products of the chemistry are detected and studied using two complementary techniques: Cavity Ring Down Spectroscopy[4] and Time-Of-Flight Mass Spectrometry[5]. Thin tholin deposits are also produced in the THS experiment and can be analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and Scanning Electron Microscopy (SEM). We will present the results of ongoing mass spectrometry studies on the THS experiment using different gas mixtures: N2-CH4, N2-C2H2, N2-C2H4, N2-C2H6, N2-C6H6, and similar mixtures with an N2-CH4 (90:10) mixture instead of pure N2, to study specific pathways

  14. Atmospheric forcing intensifies the effects of regional ocean warming on reef-scale temperature anomalies during a coral bleaching event

    Science.gov (United States)

    Zhang, Zhenlin; Falter, James; Lowe, Ryan; Ivey, Greg; McCulloch, Malcolm

    2013-09-01

    We investigate how local atmospheric conditions and hydrodynamic forcing contributed to local variations in water temperature within a fringing coral reef-lagoon system during the peak of a marine heat wave in 2010-2011 that caused mass coral bleaching across Western Australia. A three-dimensional circulation model Regional Ocean Modeling System (ROMS) with a built-in air-sea heat flux exchange module Coupled Ocean Atmosphere Experiment (COARE) was coupled with a spectral wave model Simulating Waves Nearshore (SWAN) to resolve the surface heat exchange and wave-driven reef circulation in Coral Bay, Ningaloo Reef. Using realistic oceanic and atmospheric forcing, the model predictions were in good agreement with measured time series of water temperature at various locations in the coral reef system during the bleaching event. Through a series of sensitivity analyses, we found that the difference in temperature between the reef and surrounding offshore waters (ΔT) was predominantly a function of both the daily mean net heat flux (Qnet>¯) and residence time, whereas diurnal variations in reef water temperature were dependent on the diurnal fluctuation in the net heat flux. We found that reef temperatures were substantially higher than offshore in the inner lagoon under normal weather conditions and over the entire reef domain under more extreme weather conditions (0.7°C-1.5°C). Although these temperature elevations were still less than that caused by the regional ocean warming (2°C-3°C), the arrival of peak seasonal temperatures in the summer of 2010-2011 (when net atmospheric heat fluxes were positive and abnormally high) caused substantially higher thermal stresses than would have otherwise occurred if offshore temperatures had reached their normal seasonal maxima in autumn (when net atmospheric heat fluxes were negative or cooling). Therefore, the degree heating weeks calculated based on offshore temperature substantially underestimated the thermal stresses

  15. GASEOUS MEAN OPACITIES FOR GIANT PLANET AND ULTRACOOL DWARF ATMOSPHERES OVER A RANGE OF METALLICITIES AND TEMPERATURES

    Energy Technology Data Exchange (ETDEWEB)

    Freedman, Richard S. [SETI Institute, Mountain View, CA (United States); Lustig-Yaeger, Jacob [Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Lupu, Roxana E.; Marley, Mark S. [Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, CA (United States); Lodders, Katharina, E-mail: Richard.S.Freedman@nasa.gov [Planetary Chemistry Laboratory, Washington University, St. Louis, MO (United States)

    2014-10-01

    We present new calculations of Rosseland and Planck gaseous mean opacities relevant to the atmospheres of giant planets and ultracool dwarfs. Such calculations are used in modeling the atmospheres, interiors, formation, and evolution of these objects. Our calculations are an expansion of those presented in Freedman et al. to include lower pressures, finer temperature resolution, and also the higher metallicities most relevant for giant planet atmospheres. Calculations span 1 μbar to 300 bar, and 75-4000 K, in a nearly square grid. Opacities at metallicities from solar to 50 times solar abundances are calculated. We also provide an analytic fit to the Rosseland mean opacities over the grid in pressure, temperature, and metallicity. In addition to computing mean opacities at these local temperatures, we also calculate them with weighting functions up to 7000 K, to simulate the mean opacities for incident stellar intensities, rather than locally thermally emitted intensities. The chemical equilibrium calculations account for the settling of condensates in a gravitational field and are applicable to cloud-free giant planet and ultracool dwarf atmospheres, but not circumstellar disks. We provide our extensive opacity tables for public use.

  16. GASEOUS MEAN OPACITIES FOR GIANT PLANET AND ULTRACOOL DWARF ATMOSPHERES OVER A RANGE OF METALLICITIES AND TEMPERATURES

    International Nuclear Information System (INIS)

    We present new calculations of Rosseland and Planck gaseous mean opacities relevant to the atmospheres of giant planets and ultracool dwarfs. Such calculations are used in modeling the atmospheres, interiors, formation, and evolution of these objects. Our calculations are an expansion of those presented in Freedman et al. to include lower pressures, finer temperature resolution, and also the higher metallicities most relevant for giant planet atmospheres. Calculations span 1 μbar to 300 bar, and 75-4000 K, in a nearly square grid. Opacities at metallicities from solar to 50 times solar abundances are calculated. We also provide an analytic fit to the Rosseland mean opacities over the grid in pressure, temperature, and metallicity. In addition to computing mean opacities at these local temperatures, we also calculate them with weighting functions up to 7000 K, to simulate the mean opacities for incident stellar intensities, rather than locally thermally emitted intensities. The chemical equilibrium calculations account for the settling of condensates in a gravitational field and are applicable to cloud-free giant planet and ultracool dwarf atmospheres, but not circumstellar disks. We provide our extensive opacity tables for public use

  17. Atmospheric correction for sea surface temperature retrieval from single thermal channel radiometer data onboard Kalpana satellite

    Indian Academy of Sciences (India)

    Naveen R Shahi; Neeraj Agarwal; Aloke K Mathur; Abhijit Sarkar

    2011-06-01

    An atmospheric correction method has been applied on sea surface temperature (SST) retrieval algorithm using Very High Resolution Radiometer (VHRR) single window channel radiance data onboard Kalpana satellite (K-SAT). The technique makes use of concurrent water vapour fields available from Microwave Imager onboard Tropical Rainfall Measuring Mission (TRMM/TMI) satellite. Total water vapour content and satellite zenith angle dependent SST retrieval algorithm has been developed using Radiative Transfer Model [MODTRAN ver3.0] simulations for Kalpana 10.5–12.5 m thermal window channel. Retrieval of Kalpana SST (K-SST) has been carried out for every half-hourly acquisition of Kalpana data for the year 2008 to cover whole annual cycle of SST over Indian Ocean (IO). Validation of the retrieved corrected SST has been carried out using near-simultaneous observations of ship and buoys datasets covering Arabian Sea, Bay of Bengal and IO regions. A significant improvement in Root Mean Square Deviation (RMSD) of K-SST with respect to buoy (1.50–1.02 K) and to ship datasets (1.41–1.19 K) is seen with the use of near real-time water vapour fields of TMI. Furthermore, comparison of the retrieved SST has also been carried out using near simultaneous observations of TRMM/TMI SST over IO regions. The analysis shows that K-SST has overall cold bias of 1.17 K and an RMSD of 1.09 K after bias correction.

  18. High throughput measurement of high temperature strength of ceramics in controlled atmosphere and its use on solid oxide fuel cell anode supports

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Curran, Declan; Rasmussen, Steffen;

    2014-01-01

    In the development of structural and functional ceramics for high temperature electrochemical conversion devices such as solid oxide fuel cells, their mechanical properties must be tested at operational conditions, i.e. at high temperature and controlled atmospheres. Furthermore, characterization...

  19. On the Observed Relationships between Variability in Gulf Stream Sea Surface Temperatures and the Atmospheric Circulation in the North Atlantic

    Science.gov (United States)

    Wills, Samantha; Thompson, David; Ciasto, Laura

    2016-04-01

    The advent of increasingly high-resolution satellite observations and numerical models has led to a series of advances in our understanding of the role of midlatitude sea surface temperature (SST) in climate variability, especially near western boundary currents (WBC). Observational analyses have suggested that ocean dynamics play a central role in driving interannual SST variability over the Kuroshio-Oyashio and Gulf Stream extensions. Numerical experiments have suggested that variations in the SST field within these WBC regions may have a much more pronounced influence on the atmospheric circulation than previously thought. In this study, the authors examine the observational support for (or against) a robust atmospheric response to midlatitude SST variability in the Gulf Stream extension. To do so, lead/lag analysis based on daily-mean data is applied to assess the evidence for two-way coupling between SST anomalies and the atmospheric circulation on transient timescales, building off of previous studies that have utilized weekly data. A novel decomposition approach is employed to demonstrate that atmospheric circulation anomalies over the Gulf Stream extension can be separated into two distinct patterns of midlatitude atmosphere/ocean interaction: 1) a pattern that peaks 2-3 weeks before the largest SST anomalies in the Gulf Stream extension, which can be viewed as the "atmospheric forcing" and 2) a pattern that peaks several weeks after the largest SST anomalies, which the authors argue can be viewed as the "atmospheric response". The latter pattern is linearly independent of the former, and is interpreted as the potential response of the atmospheric circulation to SST variability in the Gulf Stream extension.

  20. Validation of gas temperature measurements by OES in an atmospheric air glow discharge with water electrode using Rayleigh scattering

    Energy Technology Data Exchange (ETDEWEB)

    Verreycken, T; Van Gessel, A F H; Pageau, A; Bruggeman, P, E-mail: p.j.bruggeman@tue.n [Eindhoven University of Technology, Department of Applied Physics, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2011-04-15

    Rayleigh scattering is used to determine the gas temperature of an atmospheric pressure dc excited glow discharge in air with a water electrode. The obtained temperatures are compared with calculated rotational temperatures measured by optical emission spectroscopy of OH(A-X) and N{sub 2}(C-B). At a current of 15 mA a deviation is found between T{sub rot}(OH) and the gas temperature obtained from Rayleigh scattering of about 1000 K. The gas temperatures obtained from Rayleigh scattering, N{sub 2}(C) and OH(A) in the positive column are, respectively, 2600 {+-} 100 K, 2700 {+-} 150 K and 3600 {+-} 200 K. It is shown that the rotational temperature of N{sub 2}(C) is a reliable measurement of the gas temperature while this is not the case for OH(A). The results are explained in the context of quenching processes of the excited states. Spatially resolved gas temperatures in both longitudinal and radial directions are presented. The observed strong temperature gradients near the electrodes are checked to be consistent with the power dissipation and the heat transfer in the discharge. The effect of the polarity of the water electrode and filamentation on the measured temperatures is discussed.

  1. Atmospheric and Coupled Model Intercomparison in Terms of Amplitude-Phase Characteristics of Surface Air Temperature Annual Cycle

    Institute of Scientific and Technical Information of China (English)

    Alexey V. ELISEEV; Igor I. MOKHOV; Konstantin G. RUBINSTEIN; Maria S. GUSEVA

    2004-01-01

    A model intercomparison in terms of surface air temperature annual cycle ampitude-phase characteristics(SAT AC APC)is performed. The models included in the intercomparison belong to two groups:five atmospheric models with prescribed sea surface temperature and sea ice cover and four coupled models forced by the atmospheric abundances of anthropogenic consituents (in total six coupled model simulations). Over land, the models, simulating higher than observed time averaged SAT,also tend to simulate smaller than observed amplitude of its annual and semiannual harmonics and (outside the Tropics laterthan-observed spring and autumn moments. The models with larger(smaller) time averaged amplitudes of annual and semiannual harmonics also tend to simulate larger(smaller)interannual standard deviations. Over the oceans, the coupled models with larger interannual standard deviations of annual mean SAT tend to simulate larger interannual standard deviations of both annual and semiannual SAT harmonics amplitudes. Most model errors are located in the belts 60°-70°N and 60°-70°S and over Antarctica. These errors are larger for those coupled models which do not employ dynamical modules for sea ice.No systematic differences are found in the simulated time averaged fields of the surface air temperature annual cycle characteristics for atmospheric models on one hand and for the coupled models on the other. But the coupled models generally simulate interannual variability of SAT AC APC better than the atmospheric models (which tend to underestimate it). For the coupled models, the results are not very sensitive to the choice of the particular scenario of anthropogenic forcing.There is a strong linear positive relationship between the model simulated time averaged semiannual SAT harmonics amplitude and interannual standard deviation of annual mean SAT.It is stronger over the tropical oceans and is weaker in the extratropics. In the tropical oceanic areas, it is stronger for the

  2. High Temperature Corrosion of Fe-C-S Cast Irons in Oxidizing and Sulfidizing Atmospheres

    Institute of Scientific and Technical Information of China (English)

    Thuan-Dinh NGUYEN; Dong-Bok LEE

    2008-01-01

    The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Feo.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.

  3. Temporal Variations of Titan's Middle-Atmospheric Temperatures from 2004 to 2009 Observed by Cassini/CIRS

    Science.gov (United States)

    Achterberg, Richard K.; Gierasch, Peter J.; Conrath, Barney J.; Flasar, F. Michael; Nixon, Conor A.

    2011-01-01

    We use five and one-half years of limb- and nadir-viewing temperature mapping observations by the Composite Infrared Radiometer-Spectrometer (CIRS) on the Cassini Saturn orbiter, taken between July 2004 and December 2009 (Ls from 293 deg. to 48 deg.; northern mid-winter to just after northern spring equinox), to monitor temperature changes in the upper stratosphere and lower mesosphere of Titan. The largest changes are in the northern (winter) polar stratopause, which has declined in temperature by over 20 K between 2005 and 2009. Throughout the rest of the mid to upper stratosphere and lower mesosphere, temperature changes are less than 5 K. In the southern hemisphere, temperatures in the middle stratosphere near 1 mbar increased by 1-2 K from 2004 through early 2007, then declined by 2-4 K throughout 2008 and 2009, with the changes being larger at more polar latitudes. Middle stratospheric temperatures at mid-northern latitudes show a small 1-2 K increase from 2005 through 2009, at north polar latitudes within the polar vortex, temperatures in the middle stratosphere show an approximately 4 K increase during 2007, followed by a comparable decrease in temperatures in 2008 and into early 2009. The observed temperature changes in the north polar region are consistent with a weakening of the subsidence within the descending branch of the middle atmosphere meridional circulation.

  4. Temperature and atmospheric pressure may be considered as predictors for the occurrence of bacillary dysentery in Guangzhou, Southern China

    Directory of Open Access Journals (Sweden)

    Tiegang Li

    2014-06-01

    Full Text Available Introduction The control of bacillary dysentery (BD remains a big challenge for China. Methods Negative binomial multivariable regression was used to study relationships between meteorological variables and the occurrence of BD during the period of 2006-2012. Results Each 1°C rise of temperature corresponded to an increase of 3.60% (95%CI, 3.03% to 4.18% in the monthly number of BD cases, whereas a 1 hPa rise in atmospheric pressure corresponded to a decrease in the number of BD cases by 2.85% (95%CI = 3.34% to 2.37% decrease. Conclusions Temperature and atmospheric pressure may be considered as predictors for the occurrence of BD in Guangzhou.

  5. Understanding convection features over Bay of Bengal using sea surface temperature and atmospheric variables

    Science.gov (United States)

    Uma, R.; Lakshmi Kumar, T. V.; Narayanan, M. S.

    2016-08-01

    Tropical oceanic regions are frequently prone to deep convections. Hence, it is very essential to understand the features of convection with the help of oceanic and atmospheric variables such as sea surface temperature (SST), outgoing longwave radiation (OLR), rainfall, relative humidity, columnar water vapour (CWV) etc. and the linkage among them. In our present study, we have divided the Bay of Bengal (BoB) into ten different subregions (SR) and have attempted to study the connection between the above-stated variables during convective and non-convective events in the southwest monsoon (SWM) season (June to September) for the period 1998-2010. The monthly behaviour of SST/OLR decreased by 0.5 °C/14 W/m2 from May to June and increased by 0.1 °C/7 W/m2 from September to October. Among the ten SRs, SR 5 and SR 10 are observed to be coldest and warmest, respectively, based on the SST variations. Intra-seasonal oscillations of the above-mentioned variables show the influences of quasi-biweekly oscillations (QBWO) and Madden-Julian oscillations (MJO). As the threshold values for SST, OLR and rainfall were already reported, we have drawn our attention to deduce a threshold value for water vapour in lower level troposphere (water vapour density (WVD) at 850 mb) which highly influences the convection. In arriving at a threshold of low-level water vapour, we have analysed the convective and non-convective events of each central 1 × 1° grid in all the SRs for the period from 1998 to 2010, along with water vapour scale height. Our analysis inferred that the low-level water vapour density at 850 mb varied above 12 g/m3during convective days and below 12 g/m3during non-convective days. We noticed that the variability in water vapour density is more in non-convective days than in convective days over BoB. The results of the study may be useful to understand the water vapour dynamics with SST, OLR and rainfall.

  6. Trends in persistent seasonal-scale atmospheric circulation patterns responsible for precipitation and temperature extremes in California

    Science.gov (United States)

    Swain, D. L.; Horton, D. E.; Singh, D.; Diffenbaugh, N. S.

    2015-12-01

    Long-lived anomalous atmospheric circulation patterns are often associated with surface weather extremes. This is particularly true from a hydroclimatic perspective in regions that have well-defined "wet seasons," where atmospheric anomalies that persist on a seasonal scale can lead to drought or (conversely) increase the risk of flood. Recent evidence suggests that both natural variability and global warming may be responsible for spatially and temporally heterogeneous changes in Northern Hemisphere atmospheric conditions over the past several decades. In this investigation, we assess observed trends in cool-season (Oct-May) circulation patterns over the northeastern Pacific Ocean which have historically been associated with precipitation and temperature extremes in California. We find that the occurrence of certain extreme seasonal-scale atmospheric configurations has changed substantially over the 1948-2015 period, and also that there has been a trend towards amplification of the cool-season mean state in this region. Notably, patterns similar to the persistent anticyclone associated with the extremely warm and dry conditions experienced during the ongoing 2012-2015 California drought occur more frequently in the second half of the observed record. This finding highlights the importance of examining changes in extreme and/or persistent atmospheric circulation configurations, which may exhibit different responses to natural and anthropogenic forcings than the mean state.

  7. Radiative analysis of global mean temperature trends in the middle atmosphere: Effects of non-locality and secondary absorption bands

    Science.gov (United States)

    Fomichev, V. I.; Jonsson, A. I.; Ward, W. E.

    2016-02-01

    In this paper, we provide a refined and extended assignment of past and future temperature changes relative to previous analyses and describe and evaluate the relevance of vertical coupling and non-linear and secondary radiative mechanisms for the interpretation of climatic temperature variations in the middle atmosphere. Because of their nature, the latter mechanisms are not adequately accounted for in most regression analyses of temperature trends as a function of local constituent variations. These mechanisms are examined using (1) globally averaged profiles from transient simulations with the Canadian Middle Atmosphere Model (CMAM) forced by changes in greenhouse gases and ozone depleting substances and (2) a one-dimensional radiative-equilibrium model forced using the diagnosed global mean changes in radiatively active constituents as derived from the CMAM model runs. The conditions during the periods 1975 to 1995 and 2010 to 2040 (during which the rates of change in ozone and CO2 differ) provide a suitable contrast for the role of the non-linear and non-local mechanisms being evaluated in this paper to be clearly differentiated and evaluated. Vertical coupling of radiative transfer effects and the influence of secondary absorption bands are important enough to render the results of multiple linear regression analyses between the temperature response and constituent changes misleading. These effects are evaluated in detail using the 1D radiative-equilibrium model using profiles from the CMAM runs as inputs. In order to explain the differences in the CMAM temperature trends prior to and after 2000 these other radiative effects must be considered in addition to local changes in the radiatively active species. The middle atmosphere temperature cools in response to CO2 and water vapor increases, but past and future trends are modulated by ozone changes.

  8. Mutation Breeding of Extracellular Polysaccharide-Producing Microalga Crypthecodinium cohnii by a Novel Mutagenesis with Atmospheric and Room Temperature Plasma

    OpenAIRE

    Bin Liu; Zheng Sun; Xiaonian Ma; Bo Yang; Yue Jiang; Dong Wei; Feng Chen

    2015-01-01

    Extracellular polysaccharides (EPS) produced by marine microalgae have the potential to be used as antioxidants, antiviral agents, immunomodulators, and anti-inflammatory agents. Although the marine microalga Crypthecodinium cohnii releases EPS during the process of docosahexaenoic acid (DHA) production, the yield of EPS remains relatively low. To improve the EPS production, a novel mutagenesis of C. cohnii was conducted by atmospheric and room temperature plasma (ARTP). Of the 12 mutants o...

  9. Temperature-programmed desorption of oxygen from La-Sr-Co-Fe perovskite in atmospheres with varying oxygen partial pressure

    International Nuclear Information System (INIS)

    A temperature-programmed desorption technique under atmospheres with variable partial pressure of oxygen has been developed using a homemade fixed-bed flow reactor equipped with a yttria-stabilized zirconia (YSZ) oxygen sensor as a detector of oxygen desorbed from a sample. Its significance has been verified for the particular catalytic material of La-Sr-Co-Fe-O perovskite-type oxide. (author)

  10. Design and fabrication of a data logger for atmospheric pressure, temperature and relative humidity for gas-filled detector development

    CERN Document Server

    Sahu, S; Rudra, Sharmili; Biswas, S; Mohanty, B; Sahu, P K

    2015-01-01

    A novel instrument has been developed to monitor and record the ambient pa- rameters such as temperature, atmospheric pressure and relative humidity. These parameters are very essential for understanding the characteristics such as gain of gas filled detectors like Gas Electron Multiplier (GEM) and Multi Wire Propor- tional Counter (MWPC). In this article the details of the design, fabrication and operation processes of the device has been presented.

  11. Temperature Measurements in Venus Upper Atmosphere between 2007 and 2015 from ground-based Infrared Heterodyne Spectroscopy

    Science.gov (United States)

    Krause, Pia; Wischnewski, Carolin; Sornig, Manuela; Stangier, Tobias; Sonnabend, Guido; Herrmann, Maren; Wiegand, Moritz; Kostiuk, Theodor; Livengood, Timothy

    2016-04-01

    The structure of Venus atmosphere has been the target of intense studies in the past decade. Among manifold ground based observations, the recent space mission Venus Express in particular has shed light on many open questions concerning the thermal and the dynamical behavior of its atmosphere. A comprehensive understanding of this atmospheric region is still missing. Therefore, direct measurements of atmospheric parameters on various time scales and at different locations on the planet are essential for an understanding and for the validation of global circulation models. Such observations are provided by the infrared heterodyne spectrometers THIS (University of Cologne), HIPWAC (NASA GSFC) and MILAHI (Tohoku University). These instruments fully resolve CO2 non-LTE emission lines for Doppler-wind and temperature retrievals at an pressure level of 1μbar (~110 km) by operating around 10μm. The Long- and short-term variability of daytime temperatures at the ~1μbar level from ground-based observing campaigns between 2007 to 2015 shall be presented. The observations yield a large quantity of temperature measurements at different positions on the planetary disk which allows to map a good part of the dayside of Venus. In addition a detailed study of the interesting but not well understood and only poorly investigated area close to the terminator will be given. Investigations on the general behavior of the temperature and differences between the morning and evening terminators are accomplished. Ongoing analysis of thermal variability and comparison to other observing methods and model calculations are in progress and will be included in the presentation if already available.

  12. Quality of fresh retail pork cuts stored in modified atmosphere under temperature conditions simulating export to distant markets.

    Science.gov (United States)

    McMullen, L M; Stiles, M E

    1994-01-01

    The effect of storage temperature on microbial and sensory quality of retail cuts of pork was determined on samples stored under temperature regimens designed to simulate conditions that could be encountered in accessing distant markets with retail-ready product. Samples were packaged in modified atmosphere with 100% CO(2) and export of retail-ready pork cuts to distant markets with a three-week time for delivery to market at -1·5°C can be achieved with one to two weeks of marketing time at retail market at 4 to 7°C.

  13. A Novel Continuously Initiated Polymerization by One-Atmosphere Low Temperature Plasma Device

    Institute of Scientific and Technical Information of China (English)

    You qingliang; Meng yuedong; Wang jianhua; Ou qiongrong; Xu xu; Zhong shaofeng

    2005-01-01

    A novel atmospheric plasma device developed in this paper, which is more effective and convenient to study the plasma-initiated polymerization (PIP) than conventional setup. The structure and mechanism of the device is introduced. Some plasma-initiated polymerization experiments are carried out on the device, and the conversion of AA (Acrylic acid) and AM (Acryl amide) atmospheric (N2) plasma polymerization are respectively 89% and 94% after 120 h post polymerization, whereby IR spectra of the product (AA, AM). Our PIP result are confirmed.

  14. UAS and DTS: Using Drones and Fiber Optics to Measure High Resolution Temperature of the Atmospheric Boundary Layer

    Science.gov (United States)

    Predosa, R. A.; Darricau, B.; Higgins, C. W.

    2015-12-01

    The atmospheric boundary layer (ABL) is the lowest part of the atmosphere that directly interacts with the planet's surface. The development of the ABL plays a vital role, as it affects the transport of atmospheric constituents such as air pollutants, water vapor, and greenhouse gases. Measurements of the processes in the ABL have been difficult due to the limitations in the spatial and temporal resolutions of the equipment as well as the height of the traditional flux tower. Recent advances in the unmanned aerial vehicle (UAV) and distributed temperature sensing (DTS) technologies have provided us with new tools to study the complex processes in ABL. We conducted a series of pioneering experiments in Eastern Oregon using a platform that combines UAV and DTS to collect data during morning and evening transitions in the ABL. The major components of this platform consists of a quad-copter, a DTS computer unit, and a set of customized fiber optic cables. A total of 75 flights were completed to investigate: (1) the capability of a duplexed fiber optic cable to reduce noise in the high spatial and temporal temperature measurements taken during the morning transition; (2) the possibility of using fiber optic cable as "wet bulb" thermometer to calculate relative humidity in the ABL at high spatial and temporal resolution. The preliminary results showed that using a fiber optic cable in a duplexed configuration with the UAV-DTS platform can effectively reduce noise level during the morning transition data collection. The customized "wet bulb" fiber optic cable is capable of providing information for the calculation of relative humidity in the ABL at unprecedented spatial and temporal resolutions. From this study, the UAV-DTS platform demonstrated great potential in collecting temperature data in the ABL and with the development of atmospheric sensor technologies, it will have more applications in the future.

  15. Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature Differences. II. Comparison with Observations

    CERN Document Server

    Komacek, Thaddeus D; Tan, Xianyu

    2016-01-01

    The full-phase infrared light curves of low-eccentricity hot Jupiters show a trend of increasing fractional dayside-nightside brightness temperature difference with increasing incident stellar flux, both averaged across the infrared and in each individual wavelength band. The analytic theory of Komacek & Showman (2016) shows that this trend is due to the decreasing ability with increasing incident stellar flux of waves to propagate from day to night and erase temperature differences. Here, we compare the predictions of this theory to observations, showing that it explains well the shape of the trend of increasing dayside-nightside temperature difference with increasing equilibrium temperature. Applied to individual planets, the theory matches well with observations at high equilibrium temperatures but systematically under-predicts the dayside-nightside brightness temperature differences at equilibrium temperatures less than $2000 \\ \\mathrm{K}$. We interpret this as likely due to as the effects of clouds m...

  16. Experimental study on the minimum ignition temperature of coal dust clouds in oxy-fuel combustion atmospheres.

    Science.gov (United States)

    Wu, Dejian; Norman, Frederik; Verplaetsen, Filip; Van den Bulck, Eric

    2016-04-15

    BAM furnace apparatus tests were conducted to investigate the minimum ignition temperature of coal dusts (MITC) in O2/CO2 atmospheres with an O2 mole fraction from 20 to 50%. Three coal dusts: Indonesian Sebuku coal, Pittsburgh No.8 coal and South African coal were tested. Experimental results showed that the dust explosion risk increases significantly with increasing O2 mole fraction by reducing the minimum ignition temperature for the three tested coal dust clouds dramatically (even by 100°C). Compared with conventional combustion, the inhibiting effect of CO2 was found to be comparatively large in dust clouds, particularly for the coal dusts with high volatile content. The retardation effect of the moisture content on the ignition of dust clouds was also found to be pronounced. In addition, a modified steady-state mathematical model based on heterogeneous reaction was proposed to interpret the observed experimental phenomena and to estimate the ignition mechanism of coal dust clouds under minimum ignition temperature conditions. The analysis revealed that heterogeneous ignition dominates the ignition mechanism for sub-/bituminous coal dusts under minimum ignition temperature conditions, but the decrease of coal maturity facilitates homogeneous ignition. These results improve our understanding of the ignition behaviour and the explosion risk of coal dust clouds in oxy-fuel combustion atmospheres. PMID:26799218

  17. Influence of Changing Atmospheric Circulation on Precipitation δ 18O-Temperature Relations in Canada during the Holocene

    Science.gov (United States)

    Edwards, Thomas W. D.; Wolfe, Brent B.; Macdonald, Glen M.

    1996-11-01

    Postglacial precipitation δ 18O history has been reconstructed for two regions of Canada. Long-term shifts in the oxygen-isotope composition of annual precipitation (δ 18O p) in southern Ontario appear to have occurred with a consistent isotope-temperature relation throughout the past 11,500 14C yr. The modern isotope-temperature relation in central Canada near present boreal treeline evidently became established between 5000 and 4000 years ago, although the relation during the last glacial maximum and deglaciation may also have been similar to present. In the early Holocene, however, unusually high δ 18O papparently persisted, in spite of low temperature locally, probably associated with high zonal index. A rudimentary sensitivity analysis suggests that a small reduction in distillation of moisture in Pacific air masses traversing the western Cordillera, perhaps accompanied by a higher summer:winter precipitation ratio, could have been responsible for the observed effect. Equivalent isotope-temperature "anomalies" apparently occurred elsewhere in western North America in response to changing early-Holocene atmospheric circulation patterns, suggesting that a time-slice map of δ 18O pfor North America during this period might provide a useful target for testing and validation of atmospheric general circulation model simulations using isotopic water tracers.

  18. Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003-2014

    Science.gov (United States)

    Eriksen Holmen, Silje; Hall, Chris M.; Tsutsumi, Masaki

    2016-06-01

    Neutral temperatures at 90 km height above Tromsø, Norway, have been determined using ambipolar diffusion coefficients calculated from meteor echo fading times using the Nippon/Norway Tromsø Meteor Radar (NTMR). Daily temperature averages have been calculated from November 2003 to October 2014 and calibrated against temperature measurements from the Microwave Limb Sounder (MLS) on board Aura. Large-scale periodic oscillations ranging from ˜ 9 days to a year were found in the data using Lomb-Scargle periodogram analysis, and these components were used to seasonally detrend the daily temperature values before assessing trends. Harmonic oscillations found are associated with the large-scale circulation in the middle atmosphere together with planetary and gravity wave activity. The overall temperature change from 2003 to 2014 is -2.2 K ± 1.0 K decade-1, while in summer (May-June-July) and winter (November-December-January) the change is -0.3 K ± 3.1 K decade-1 and -11.6 K ± 4.1 K decade-1, respectively. The temperature record is at this point too short for incorporating a response to solar variability in the trend. How well suited a meteor radar is for estimating neutral temperatures at 90 km using meteor trail echoes is discussed, and physical explanations behind a cooling trend are proposed.

  19. Diversity in neotropical wet forests during the Cenozoic is linked more to atmospheric CO2 than temperature.

    Science.gov (United States)

    Royer, Dana L; Chernoff, Barry

    2013-08-01

    Models generally predict a response in species richness to climate, but strong climate-diversity associations are seldom observed in long-term (more than 10(6) years) fossil records. Moreover, fossil studies rarely distinguish between the effects of atmospheric CO2 and temperature, which limits their ability to identify the causal controls on biodiversity. Plants are excellent organisms for testing climate-diversity hypotheses owing to their strong sensitivity to CO2, temperature and moisture. We find that pollen morphospecies richness in an angiosperm-dominated record from the Palaeogene and early Neogene (65-20 Ma) of Colombia and Venezuela correlates positively to CO2 much more strongly than to temperature (both tropical sea surface temperatures and estimates of global mean surface temperature). The weaker sensitivity to temperature may be due to reduced variance in long-term climate relative to in higher latitudes, or to the occurrence of lethal or sub-lethal temperatures during the warmest times of the Eocene. Physiological models predict that productivity should be the most sensitive to CO2 within the angiosperms, a prediction supported by our analyses if productivity is linked to species richness; however, evaluations of non-angiosperm assemblages are needed to more completely test this idea.

  20. Sterilization of packed matter by means of low temperature atmospheric pressure plasmas

    DEFF Research Database (Denmark)

    Leipold, Frank

    2010-01-01

    Summary form only given. The decontamination of material in closed containers by means of atmospheric pressure plasmas is investigated. The target is Listeria monocytogenes, a bacterium which causes listeriosis and can be found in plants and food. The non-pathogenic species, Listeria innocua, is...

  1. Sterilization of packed matter by means of low temperature atmospheric pressure plasmas

    DEFF Research Database (Denmark)

    Leipold, Frank

    2010-01-01

    Summary form only given. The decontamination of material in closed containers by means of atmospheric pressure plasmas is investigated. The target is Listeria monocytogenes, a bacterium which causes listeriosis and can be found in plants and food. The non-pathogenic species, Listeria innocua...

  2. Atmospheric pressure plasma surface modification of titanium for high temperature adhesive bonding

    NARCIS (Netherlands)

    Akram, M.; Jansen, K.M.B.; Ernst, L.J.; Bhowmik, S.

    2011-01-01

    In this investigation surface treatment of titanium is carried out by plasma ion implantation under atmospheric pressure plasma in order to increase the adhesive bond strength. Prior to the plasma treatment, titanium surfaces were mechanically treated by sand blasting. It is observed that the contac

  3. Method of enhanced lithiation of doped silicon carbide via high temperature annealing in an inert atmosphere

    Science.gov (United States)

    Hersam, Mark C.; Lipson, Albert L.; Bandyopadhyay, Sudeshna; Karmel, Hunter J; Bedzyk, Michael J

    2014-05-27

    A method for enhancing the lithium-ion capacity of a doped silicon carbide is disclosed. The method utilizes heat treating the silicon carbide in an inert atmosphere. Also disclosed are anodes for lithium-ion batteries prepared by the method.

  4. 3D modelling of the early Martian Climate under a denser CO2 atmosphere: Temperatures and CO2 ice clouds

    CERN Document Server

    Forget, Francois; Millour, Ehouarn; Madeleine, Jean-Baptiste; Kerber, Laura; Leconte, Jeremy; Marcq, Emmanuel; Haberle, Robert M

    2012-01-01

    On the basis of geological evidence, it is often stated that the early martian climate was warm enough for liquid water to flow on the surface thanks to the greenhouse effect of a thick atmosphere. We present 3D global climate simulations of the early martian climate performed assuming a faint young sun and a CO2 atmosphere with pressure between 0.1 and 7 bars. The model includes a detailed radiative transfer model using revised CO2 gas collision induced absorption properties, and a parameterisation of the CO2 ice cloud microphysical and radiative properties. A wide range of possible climates is explored by using various values of obliquities, orbital parameters, cloud microphysic parameters, atmospheric dust loading, and surface properties. Unlike on present day Mars, for pressures higher than a fraction of a bar, surface temperatures vary with altitude because of the adiabatic cooling and warming of the atmosphere when it moves vertically. In most simulations, CO2 ice clouds cover a major part of the planet...

  5. Seasonal oscillations of middle atmosphere temperature observed by Rayleigh lidars and their comparisons with TIMED/SABER observations

    Science.gov (United States)

    Dou, Xiankang; Li, Tao; Xu, Jiyao; Liu, Han-Li; Xue, Xianghui; Wang, Shui; Leblanc, Thierry; McDermid, I. Stuart; Hauchecorne, Alain; Keckhut, Philippe; Bencherif, Hassan; Heinselman, Craig; Steinbrecht, Wolfgang; Mlynczak, M. G.; Russell, J. M.

    2009-10-01

    The long-term temperature data sets obtained by Rayleigh lidars at six different locations from low to high latitudes within the Network for the Detection of Atmospheric Composition Change (NDACC) were used to derive the annual oscillations (AO) and semiannual oscillations (SAO) of middle atmosphere temperature: Reunion Island (21.8°S); Mauna Loa Observatory, Hawaii (19.5°N); Table Mountain Facility, California (34.4°N); Observatoire de Haute Provence, France (43.9°N); Hohenpeissenberg, Germany (47.8°N); Sondre Stromfjord, Greenland (67.0°N). The results were compared with those derived from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite. The zonal mean temperatures at similar latitudes show good agreement. The observations also reveal that the AO dominates the seasonal oscillations in both the stratosphere and the mesosphere at middle and high latitudes, with the amplitudes increasing poleward. The SAO oscillations are weaker at all six sites. The oscillations in the upper mesosphere are usually stronger than those in the upper stratosphere with a local minimum near 50-65 km. The upper mesospheric signals are clearly out of phase with upper stratospheric signals. Some differences between lidar and SABER results were found in both the stratosphere and mesosphere. These could be due to: the difference in data sampling between ground-based and space-based instruments, the length of data set, the tidal aliasing owing to the temperature AO and SAO since lidar data are nighttime only, and lidar temperature analysis algorithms. The seasonal oscillations of tidal amplitudes derived from SABER observations suggests that the tidal aliasing of the lidar temperature AO and SAO in the upper mesosphere may over- or under-estimate the real temperature oscillations, depending on the tidal phases. In addition, the possibly unrealistic seasonal

  6. Atmospheric Heating by Saharan Dust and Its Implication on the Temperature Profiles over the Tropical Cyclone Main Development Region

    Science.gov (United States)

    Wong, S.; Dessler, A. E.; Mahowald, N.; Yang, P.; Feng, Q.

    2007-12-01

    We have investigated anomalies in atmospheric temperature profiles that are associated with Saharan dust over the tropical cyclone main development region (10°-20°N, 20°-30°W), using temperature data from Atmospheric Infrared Sounder (AIRS) and aerosol data from Moderate Resolution Imaging Spectroradiometer (MODIS). We find that Saharan dust is associated with a vertical temperature structure that has a warm anomaly lying above the marine boundary layer (~850 hPa) and a cold anomaly throughout the middle troposphere (~350-600 hPa). We then estimate dynamical and dust radiative heating of the atmospheric column. The dynamical heating is estimated using wind and temperature data from NCEP reanalysis, while the dust radiative heating is computed using the NASA/GSFC CLIRAD radiative transfer model for both shortwave and longwave. Dust particle size distributions and vertical concentration profiles for use in the radiative transfer calculations are prescribed according to the simulation of the MATCH dust transport model. The warm anomaly in the lower tropsphere can be explained by the dynamical and dust radiative heating. For air columns with aerosol optical thickness greater than one, the dust heating rate is at least 20% of the dynamical heating rate in the lower troposphere. The cold anomaly in the middle troposphere cannot be explained by dynamical or radiative heating. Suppression of deep convection probably plays an essential role in cooling the middle troposphere over the dust layer by reduction of latent heat release. We will also investigate the sensitivity of dust radiative heating rate using assumed particle shapes for dust.

  7. Effect of oxygen concentration in modified atmosphere packaging on color and texture of beef patties cooked to different temperatures.

    Science.gov (United States)

    Bao, Yulong; Puolanne, Eero; Ertbjerg, Per

    2016-11-01

    Patties were made from raw minced beef after storage for 6days in modified atmosphere (0, 20, 40, 60, and 80% oxygen) to study the combined effect of oxygen concentration and cooking temperature on hardness and color. Increased oxygen concentrations generally led to larger (P<0.01) thiobarbituric acid-reactive substances (TBARS) values, greater (P<0.01) loss of free thiols and more formation of cross-linked myosin heavy chain. Hardness of cooked patties was generally lower (P<0.01) without oxygen. Premature browning of cooked patties was observed already at a relative low oxygen concentration of 20%. The internal redness of cooked patties decreased (P<0.05) with increasing oxygen concentrations and increasing cooking temperatures. Mean particle size (D(3,2)) of homogenized cooked meat generally increased (P<0.05) with increasing cooking temperatures and increasing oxygen concentrations, and particle size was correlated (r=0.80) with hardness of cooked patties. PMID:27341620

  8. The Mathematical Representation of Wind Speed and Temperature Profiles in the Unstable Atmospheric Surface Layer

    DEFF Research Database (Denmark)

    Paulson, C.A.

    1970-01-01

    Analytical expressions which specify non-dimensionalized wind speed and potential temperature gradients as functions of stability are integrated. The integrated equations are tested against Swinhank's wind and temperature profiles measured at Kerang, Australia. It is found that a representation s...... suggested independently by Businger and by Dyer gives the best fit to temperature profiles and describes the wind profiles equally as well as a relation suggested by Panofsky et al....

  9. Reconstruction of internal gravity wave parameters from radio occultation retrievals of vertical temperature profiles in the Earth atmosphere

    Directory of Open Access Journals (Sweden)

    V. N. Gubenko

    2011-03-01

    Full Text Available The new method for the reconstruction of internal gravity wave (IGW parameters from a single vertical temperature profile measurement in the Earth atmosphere has been developed. This method does not require any additional information not contained in the profile and may be used for the analysis of profiles measured by various techniques. The criterion for the IGW identification has been formulated and argued. In the case when this criterion is satisfied, then analyzed temperature fluctuations can be considered as wave-induced. The method is based on the analysis of relative amplitude thresholds of the temperature wave field and on the linear IGW saturation theory in which amplitude thresholds are restricted by dynamical (shear instability processes in the atmosphere. When the amplitude of an internal gravity wave reaches the shear instability limit, energy is assumed to be dissipated in such a way that the amplitude is maintained at the instability limit as the wave propagates upwards. In order to approbate the method we have used in situ data of simultaneous balloon high-resolution measurements of the temperature and wind velocity in the Earth stratosphere (France where a long-period inertia-gravity wave has been detected. Using the temperature data only, we have reconstructed all the measured wave parameters with uncertainties not larger than 30%. An application of the method to the radio occultation data has given the possibility to identify the IGWs in the Earth stratosphere and to determine the magnitudes of key wave parameters such as the intrinsic frequency, amplitudes of vertical and horizontal perturbations of the wind velocity, vertical and horizontal wavelengths, intrinsic vertical and horizontal phase (and group speeds, kinetic and potential energy, vertical fluxes of the wave energy and horizontal momentum. The obtained results of internal wave studies in the Earth stratosphere deduced from the COSMIC and CHAMP GPS occultation

  10. Reconstruction of internal gravity wave parameters from radio occultation retrievals of vertical temperature profiles in the Earth's atmosphere

    Directory of Open Access Journals (Sweden)

    V. N. Gubenko

    2011-10-01

    Full Text Available A new method for the reconstruction of internal gravity wave (IGW parameters from a single vertical temperature profile measurement in the Earth's atmosphere has been developed. This method does not require any additional information not contained in the profile and may be used for the analysis of profiles measured by various techniques. The criterion for the IGW identification has been formulated and argued. In the case when this criterion is satisfied, then analyzed temperature fluctuations can be considered as wave-induced. The method is based on the analysis of relative amplitude thresholds of the temperature wave field and on the linear IGW saturation theory in which amplitude thresholds are restricted by dynamical (shear instability processes in the atmosphere. When the amplitude of an internal gravity wave reaches the shear instability limit, energy is assumed to be dissipated in such a way that the amplitude is maintained at the instability limit as the wave propagates upwards. In order to approbate the method we have used data of simultaneous high-resolution balloon measurements of the temperature and wind velocity in the Earth's stratosphere over France where a long-period inertia-gravity wave has been detected. Using the radiosonde temperature data only, we have reconstructed all wave parameters, which were determined by radiosondes, with relative deviations not larger than 30%. An application of the method to the radio occultation (RO data has given the possibility to identify the IGWs in the Earth's stratosphere and to determine the magnitudes of key wave parameters such as the intrinsic frequency, amplitudes of vertical and horizontal perturbations of the wind velocity, vertical and horizontal wavelengths, intrinsic vertical and horizontal phase (and group speeds, kinetic and potential energy, vertical fluxes of the wave energy and horizontal momentum. The obtained results of internal wave studies in the Earth's stratosphere

  11. Temperature profiling of the atmospheric boundary layer with rotational Raman lidar during the HD(CP)2 Observational Prototype Experiment

    Science.gov (United States)

    Hammann, E.; Behrendt, A.; Le Mounier, F.; Wulfmeyer, V.

    2015-03-01

    The temperature measurements of the rotational Raman lidar of the University of Hohenheim (UHOH RRL) during the High Definition of Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observation Prototype Experiment (HOPE) in April and May 2013 are discussed. The lidar consists of a frequency-tripled Nd:YAG laser at 355 nm with 10 W average power at 50 Hz, a two-mirror scanner, a 40 cm receiving telescope, and a highly efficient polychromator with cascading interference filters for separating four signals: the elastic backscatter signal, two rotational Raman signals with different temperature dependence, and the vibrational Raman signal of water vapor. The main measurement variable of the UHOH RRL is temperature. For the HOPE campaign, the lidar receiver was optimized for high and low background levels, with a novel switch for the passband of the second rotational Raman channel. The instrument delivers atmospheric profiles of water vapor mixing ratio as well as particle backscatter coefficient and particle extinction coefficient as further products. As examples for the measurement performance, measurements of the temperature gradient and water vapor mixing ratio revealing the development of the atmospheric boundary layer within 25 h are presented. As expected from simulations, a reduction of the measurement uncertainty of 70% during nighttime was achieved with the new low-background setting. A two-mirror scanner allows for measurements in different directions. When pointing the scanner to low elevation, measurements close to the ground become possible which are otherwise impossible due to the non-total overlap of laser beam and receiving telescope field of view in the near range. An example of a low-level temperature measurement is presented which resolves the temperature gradient at the top of the stable nighttime boundary layer 100 m above the ground.

  12. Atmospheric circulation in regional climate models over Central Europe: links to surface air temperature and the influence of driving data

    Energy Technology Data Exchange (ETDEWEB)

    Plavcova, Eva [Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Prague 4 (Czech Republic); Technical University, Department of Applied Mathematics, Liberec (Czech Republic); Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Kysely, Jan [Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Prague 4 (Czech Republic); Technical University, Department of Applied Mathematics, Liberec (Czech Republic)

    2012-10-15

    The study examines simulation of atmospheric circulation, represented by circulation indices (flow direction, strength and vorticity), and links between circulation and daily surface air temperatures in regional climate models (RCMs) over Central Europe. We explore control simulations of five high-resolution RCMs from the ENSEMBLES project driven by re-analysis (ERA-40) and the same global climate model (ECHAM5 GCM) plus of one RCM (RCA) driven by different GCMs. The aims are to (1) identify errors in RCM-simulated distributions of circulation indices in individual seasons, (2) identify errors in simulated temperatures under particular circulation indices, and (3) compare performance of individual RCMs with respect to the driving data. Although most of the RCMs qualitatively reflect observed distributions of the airflow indices, each produces distributions significantly different from the observations. General biases include overestimation of the frequency of strong flow days and of strong cyclonic vorticity. Some circulation biases obviously propagate from the driving data. ECHAM5 and all simulations driven by ECHAM5 underestimate frequency of easterly flow, mainly in summer. Except for HIRHAM, however, all RCMs driven by ECHAM5 improve on the driving GCM in simulating atmospheric circulation. The influence on circulation characteristics in the nested RCM differs between GCMs, as demonstrated in a set of RCA simulations with different driving data. The driving data control on circulation in RCA is particularly weak for the BCM GCM, in which case RCA substantially modifies (but does not improve) the circulation from the driving data in both winter and summer. Those RCMs with the most distorted atmospheric circulation are HIRHAM driven by ECHAM5 and RCA driven by BCM. Relatively strong relationships between circulation indices and surface air temperatures were found in the observed data for Central Europe. The links differ by season and are usually stronger for

  13. Isoepoxydon dehydrogenase (idh) gene expression in relation to patulin production by Penicillium expansum under different temperature and atmosphere.

    Science.gov (United States)

    De Clercq, N; Vlaemynck, G; Van Pamel, E; Van Weyenberg, S; Herman, L; Devlieghere, F; De Meulenaer, B; Van Coillie, E

    2016-03-01

    Penicillium expansum growth and patulin production occur mainly at post-harvest stage during the long-term storage of apples. Low temperature in combination with reduced oxygen concentrations is commonly applied as a control strategy to extend apple shelf life and supply the market throughout the year. Our in vitro study investigated the effect of temperature and atmosphere on expression of the idh gene in relation to the patulin production by P. expansum. The idh gene encodes the isoepoxydon dehydrogenase enzyme, a key enzyme in the patulin biosynthesis pathway. First, a reverse transcription real-time PCR (RT-qPCR) method was optimized to measure accurately the P. expansum idh mRNA levels relative to the mRNA levels of three reference genes (18S, β-tubulin, calmodulin), taking into account important parameters such as PCR inhibition and multiple reference gene stability. Subsequently, two P. expansum field isolates and one reference strain were grown on apple puree agar medium (APAM) under three conditions of temperature and atmosphere: 20 °C - air, 4 °C - air and 4 °C - controlled atmosphere (CA; 3% O2). When P. expansum strains reached a 0.5 and 2.0 cm colony diameter, idh expression and patulin concentrations were determined by means of the developed RT-qPCR and an HPLC-UV method, respectively. The in vitro study showed a clear reduction in patulin production and down-regulation of the idh gene expression when P. expansum was grown under 4 °C - CA. The results suggest that stress (low temperature and oxygen level) caused a delay of the fungal metabolism rather than a complete inhibition of toxin biosynthesis. A good correlation was found between the idh expression and patulin production, corroborating that temperature and atmosphere affected patulin production by acting at the transcriptional level of the idh gene. Finally, a reliable RT-qPCR can be considered as an alternative tool to investigate the effect of control strategies on the toxin formation in

  14. Atmospheric correction of Landsat data for the retrieval of sea surface temperature in coastal waters

    Institute of Scientific and Technical Information of China (English)

    XING Qianguo; CHEN Chuqun; SHI Ping; YANG Jingkun; TANG Shilin

    2006-01-01

    A mono-window algorithm was introduced to retrieve sea surface temperature (SST) using Landsat data in coastal waters. In this algorithm, the effective mean air temperature and the water vapor content of air column were estimated with the local meteorological parameters of air temperature and relative humidity, based on the facts that in the troposphere, ( 1 ) air temperature decreases linearly with the altitude, and (2) water vapor content lapses exponentially with the altitude. The sea-truth temperature data and MODIS Terra SST product were used to validate the SST retrieved from Landsat TM and ETM + thermal infrared (TIR) data with the algorithm. The results show that the algorithm can improve the spatial temperature contrast which is often masked due to water vapor effects, and the temperature derived from the algorithm is closer to the sea-truth SST. When applying the algorithm, the initial parameters of air temperature and relative humidity can be easily collected from local meteorological stations, and there is no need to identify the model of air profile.

  15. Interdecadal Variations of Precipitation and Temperature in China Around the Abrupt Change of Atmospheric Circulation in 1976

    Institute of Scientific and Technical Information of China (English)

    LI Chunhui; WAN Qilin; LIN Ailan; GU Dejun; ZHENG Bin

    2009-01-01

    The interdecadal characteristics of rainfall and temperature in China before and after the abrupt change of the general circulation in 1976 are analyzed using the global 2.5°×2.5° monthly mean reanalysis data from the National Centers for Environmental Prediction of US and the precipitation and temperature data at the 743 stations of China from the National Climate Center of China. The results show that after 1976, springtime precipitation and temperature were anomalously enhanced and reduced respectively in South China, while the reverse was true in the western Yangtze River basin. In summer, precipitation was anomalously less in South China, more in the Yangtze River basin, less again in North China and more again in Northeast China, showing a distribution pattern alternating with negative and positive anomalies ("-, +, -, +"). Meanwhile, temperature shows a distribution of warming in South China, cooling in the Yangtze and Huaihe River basins, and warming again in northern China. In autumn, precipitation tended to decrease and temperature tended to increase in most parts of the country. In winter, precipitation increased moderately in South China and warming was the trend across all parts of China. The interdecadal decline of mean temperature in spring and summer in China was mainly due to the daily maximum temperature variation, while the interdecadal increase was mainly the result of the minimum temperature change. The overall warming in autumn (winter) was mostly influenced by the minimum (maximum) temperature variation. These changes were closely related to the north-south shifts of the ascending and descending branches of the Hadley cell, the strengthening and north-south progression of the westerly jet stream, and the atmospheric stratification and water vapor transport conditions.

  16. Future Changes Projections of Atmospheric Circulation and Precipitation and Temperature Patterns Over South America in Austral Summer

    Science.gov (United States)

    Shimizu, M. H.; Cavalcanti, I. F.

    2012-12-01

    Atmospheric circulation is primarily driven by temperature gradients across the globe due to differential heating of Earth's surface which leads to a surplus of energy in the tropics and a deficit in the high latitudes. However, due to global warming, changes in atmospheric circulation are expected, which could result in modifications also in precipitation pattern. There are some evidences of changes in atmospheric circulation, such as the expansion of tropical belt and the poleward shift of large-scale atmospheric circulation systems, such as jet streams. These changes can be enhanced in a scenario with increasing greenhouse gases concentration. The objective of this study was to analyze future changes of atmospheric circulation and precipitation and temperature patterns in the austral summer over South America under Representative Pathway Concentration 8.5 (RCP 8.5) emission scenario. This evaluation was made according to model projections based on the coordinated climate change experiments defined by Coupled Model Intercomparison Project phase 5 (CMIP5). Historical simulations were used to evaluate model performance in reproduce main climatic features over South America in the Austral Summer. This analysis showed that some models perform better than others, with a wide range of difference between simulations and Global Precipitation Climatology Project (GPCP) and European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim data sets. In general, the models captured the main features of Austral Summer such as the northwest-southeast precipitation band associated with the South Atlantic Convergence Zone (SACZ) and the anticyclonic circulation at high levels related to Bolivian High. The projections from different models pointed out in general to a reduction of precipitation, however the signal was not the same over all the continent and for all models. For example, Met Office's HadGEM2-ES projection indicated a reduction of precipitation in most of

  17. Spectroscopic Evidence for a Temperature Inversion in the Dayside Atmosphere of the Hot Jupiter WASP-33b

    CERN Document Server

    Haynes, Korey; Madhusudhan, Nikku; Deming, Drake; Knutson, Heather

    2015-01-01

    We present observations of two occultations of the extrasolar planet WASP-33b using the Wide Field Camera 3 (WFC3) on the HST, which allow us to constrain the temperature structure and composition of its dayside atmosphere. WASP-33b is the most highly irradiated hot Jupiter discovered to date, and the only exoplanet known to orbit a delta-Scuti star. We observed in spatial scan mode to decrease instrument systematic effects in the data, and removed fluctuations in the data due to stellar pulsations. The RMS for our final, binned spectrum is approximately 1.05 times the photon noise. We compare our final spectrum, along with previously published photometric data, to atmospheric models of WASP-33b spanning a wide range in temperature profiles and chemical compositions. We find that the data require models with an oxygen-rich chemical composition and a temperature profile that increases at high altitude. We also find that our spectrum displays an excess in the measured flux towards short wavelengths that is best...

  18. Influence of land-atmosphere feedbacks on temperature and precipitation extremes in the GLACE-CMIP5 ensemble

    Science.gov (United States)

    Lorenz, Ruth; Argüeso, Daniel; Donat, Markus G.; Pitman, Andrew J.; Hurk, Bart; Berg, Alexis; Lawrence, David M.; Chéruy, Frédérique; Ducharne, Agnès.; Hagemann, Stefan; Meier, Arndt; Milly, P. C. D.; Seneviratne, Sonia I.

    2016-01-01

    We examine how soil moisture variability and trends affect the simulation of temperature and precipitation extremes in six global climate models using the experimental protocol of the Global Land-Atmosphere Coupling Experiment of the Coupled Model Intercomparison Project, Phase 5 (GLACE-CMIP5). This protocol enables separate examinations of the influences of soil moisture variability and trends on the intensity, frequency, and duration of climate extremes by the end of the 21st century under a business-as-usual (Representative Concentration Pathway 8.5) emission scenario. Removing soil moisture variability significantly reduces temperature extremes over most continental surfaces, while wet precipitation extremes are enhanced in the tropics. Projected drying trends in soil moisture lead to increases in intensity, frequency, and duration of temperature extremes by the end of the 21st century. Wet precipitation extremes are decreased in the tropics with soil moisture trends in the simulations, while dry extremes are enhanced in some regions, in particular the Mediterranean and Australia. However, the ensemble results mask considerable differences in the soil moisture trends simulated by the six climate models. We find that the large differences between the models in soil moisture trends, which are related to an unknown combination of differences in atmospheric forcing (precipitation, net radiation), flux partitioning at the land surface, and how soil moisture is parameterized, imply considerable uncertainty in future changes in climate extremes.

  19. Changes in flavonoids of sliced and fried yellow onions (allium cepa L. var. zittauer) during storage at different atmospheric, temperature and light conditions

    DEFF Research Database (Denmark)

    Islek, Merve; Nilufer-Erdil, Dilara; Knuthsen, Pia

    2015-01-01

    Flavonoid changes in sliced and fried onions which were packed and stored at different atmospheric conditions (air, nitrogen and vacuum), temperatures (ambient, +5 and -18C) and light (dark or light) were investigated. Flavonoids were extracted using accelerated solvent extraction and analyzed us......, or -18C, vacuum or nitrogen atmosphere, under dark, preserved flavonoids for 21 days, whereas for fried onions, 7 days of storage at +5C, vacuum atmosphere under dark resulted in highest flavonoid content. © 2014 Wiley Periodicals, Inc....

  20. Transfer and distortion of atmospheric information in the satellite temperature retrieval problem

    Science.gov (United States)

    Thompson, O. E.

    1981-01-01

    A systematic approach to investigating the transfer of basic ambient temperature information and its distortion by satellite systems and subsequent analysis algorithms is discussed. The retrieval analysis cycle is derived, the variance spectrum of information is examined as it takes different forms in that process, and the quality and quantity of information existing at each stop is compared with the initial ambient temperature information. Temperature retrieval algorithms can smooth, add, or further distort information, depending on how stable the algorithm is, and how heavily influenced by a priori data.

  1. The effects of re-firing process under oxidizing atmosphere and temperatures on the properties of strontium aluminate phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Karacaoglu, Erkul, E-mail: erkaracaoglu@gmail.com [Anadolu University, Graduate School of Sciences, Department of Materials Science and Engineering, Eskisehir (Turkey); Fosfortek Phosphor Technologies Co., Eskisehir (Turkey); Karasu, Bekir [Anadolu University, Materials Science and Engineering Department, Eskisehir (Turkey)

    2013-10-15

    Graphical abstract: The comparative emission spectra of standard and re-fired Phosphor A under oxidizing atmosphere at various temperatures. The colour of Phosphor A re-fired at higher temperatures above 900 °C shifted from yellowish-green to bluish-green in the dark. But, the bluish-green emission could only be seen when it was exposed to UV and disappeared as soon as the light source was removed. Moreover, the emission intensities decreased as the re-firing temperatures increased. This could be attributed to the oxidation of Eu{sup 2+} during the re-firing process. It is well known fact from the literature that the reduction of Eu{sup 3+} to Eu{sup 2+} in appropriate host materials needs an annealing process in a reducing atmosphere such as H{sub 2}, H{sub 2}/N{sub 2} mixture or CO. Up to now, the reduction phenomena of Eu{sup 3+} → Eu{sup 2+} in air have been found in phosphates (Ba{sub 3}(PO{sub 4}){sub 2}:Eu), sulphates (BaSO{sub 4}:Eu), borates (SrB{sub 4}O{sub 7}:Eu, SrB{sub 6}O{sub 10}:Eu and BaB{sub 8}O{sub 13}:Eu) and aluminates (Sr{sub 4}Al{sub 14}O{sub 25}:Eu). Interestingly, an apparent blue shift in the phosphorescence spectrum was observed in the samples re-fired at 1000 °C and above, indicating a minimal effect on the oxidation state or the electronic energy levels of the co-doped Dy{sup 3+} ions, which were thought to act as long-lived hole traps resulting in long afterglow. - Highlights: • This study examines the effects re-firing at oxidizing atmosphere of photoluminescence of three different commercial SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+}-phosphors. • All the commercial SrAl{sub 2}O{sub 4}:Eu{sup 2+},Dy{sup 3+}-phosphors completely lost their phosphorescence after being re-fired at 1300 °C. • Oxidizing environment and re-firing temperature naturally affecting the valance of Eu{sup 2+} may cause the basic lattice structure to be modified and also limit their applications at higher temperatures, such as third firing vetrosa d

  2. High Temperature Energy Storage for In Situ Planetary Atmospheric Measurement Technologies Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of energy storage capable of operational temperatures of 380:C and 486oC with a specific capacity 200 Wh/kg for use as a power source on the Venusian...

  3. NOAA Climate Data Record (CDR) of Reflectance and Brightness Temperatures from AVHRR Pathfinder Atmospheres - Extended (PATMOS-x), Version 5.3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This NOAA Climate Data Record (CDR) of AVHRR reflectance and brightness temperatures was produced by the University of Wisconsin using the AVHRR Pathfinder...

  4. A theoretical study of a two-wavelength lidar technique for the measurement of atmospheric temperature profiles

    Science.gov (United States)

    Korb, C. L.; Weng, C. Y.

    1982-01-01

    The theory of differential absorption lidar measurements for lines with a Voigt profile is given and applied to a two-wavelength technique for measuring the atmospheric temperature profile using a high J line in the oxygen A band. Explicit expressions for the temperature and pressure dependence of the absorption coefficient are developed for lines with a Voigt profile. An iteration procedure for calculating the temperature for narrow laser bandwidths is described which has an accuracy better than 0.2 K for bandwidths less than 0.01/cm. To reduce the errors in lidar measurements due to uncertainties in pressure, a method for estimating the pressure from the temperature profile is described. A procedure for extending the differential absorption technique to the case of finite laser bandwidth with good accuracy is also described. Simulation results show that a knowledge of the laser frequency is needed to 0.005/cm for accurate temperature measurements. Evaluation of the sensitivity for both ground- and Shuttle-based measurements shows accuracies generally better than 1 K. This technique allows up to an order of magnitude improvement in sensitivity compared to other differential absorption lidar techniques.

  5. Inter-annual temperature and precipitation variations over the Litani Basin in response to atmospheric circulation patterns

    Science.gov (United States)

    Ramadan, H. H.; Ramamurthy, A. S.; Beighley, R. E.

    2012-05-01

    This study examines the sensitivity of a mid-size basin's temperature and precipitation response to different global and regional climate circulation patterns. The implication of the North Atlantic Oscillation (NAO), El Niño Southern Oscillation (ENSO), Indian Monsoon and ten other teleconnection patterns of the Northern Hemisphere are investigated. A methodology to generate a basin-scale, long-term monthly surface temperature and precipitation time series has been established using different statistical tests. The Litani River Basin is the focus of this study. It is located in Lebanon, east of the Mediterranean Basin, which is known to have diverse geophysical and environmental characteristics. It was selected to explore the influence of the diverse physical and topographical features on its hydroclimatological response to global and regional climate patterns. We also examine the opportunity of conducting related studies in areas with limited long-term measured climate and/or hydrological data. Litani's monthly precipitation and temperature data have been collected and statistically extrapolated using remotely sensed data products from satellites and as well as in situ gauges. Correlations between 13 different teleconnection indices and the basin's precipitation and temperature series are investigated. The study shows that some of the annual and seasonal temperature and precipitation variance can be partially associated with many atmospheric circulation patterns. This would give the opportunity to relate the natural climate variability with the watershed's hydroclimatology performance and thus differentiate it from other anthropogenic induced climate change outcomes.

  6. An atmospheric pressure high-temperature laminar flow reactor for investigation of combustion and related gas phase reaction systems.

    Science.gov (United States)

    Oßwald, Patrick; Köhler, Markus

    2015-10-01

    A new high-temperature flow reactor experiment utilizing the powerful molecular beam mass spectrometry (MBMS) technique for detailed observation of gas phase kinetics in reacting flows is presented. The reactor design provides a consequent extension of the experimental portfolio of validation experiments for combustion reaction kinetics. Temperatures up to 1800 K are applicable by three individually controlled temperature zones with this atmospheric pressure flow reactor. Detailed speciation data are obtained using the sensitive MBMS technique, providing in situ access to almost all chemical species involved in the combustion process, including highly reactive species such as radicals. Strategies for quantifying the experimental data are presented alongside a careful analysis of the characterization of the experimental boundary conditions to enable precise numeric reproduction of the experimental results. The general capabilities of this new analytical tool for the investigation of reacting flows are demonstrated for a selected range of conditions, fuels, and applications. A detailed dataset for the well-known gaseous fuels, methane and ethylene, is provided and used to verify the experimental approach. Furthermore, application for liquid fuels and fuel components important for technical combustors like gas turbines and engines is demonstrated. Besides the detailed investigation of novel fuels and fuel components, the wide range of operation conditions gives access to extended combustion topics, such as super rich conditions at high temperature important for gasification processes, or the peroxy chemistry governing the low temperature oxidation regime. These demonstrations are accompanied by a first kinetic modeling approach, examining the opportunities for model validation purposes. PMID:26520986

  7. An atmospheric pressure high-temperature laminar flow reactor for investigation of combustion and related gas phase reaction systems

    Science.gov (United States)

    Oßwald, Patrick; Köhler, Markus

    2015-10-01

    A new high-temperature flow reactor experiment utilizing the powerful molecular beam mass spectrometry (MBMS) technique for detailed observation of gas phase kinetics in reacting flows is presented. The reactor design provides a consequent extension of the experimental portfolio of validation experiments for combustion reaction kinetics. Temperatures up to 1800 K are applicable by three individually controlled temperature zones with this atmospheric pressure flow reactor. Detailed speciation data are obtained using the sensitive MBMS technique, providing in situ access to almost all chemical species involved in the combustion process, including highly reactive species such as radicals. Strategies for quantifying the experimental data are presented alongside a careful analysis of the characterization of the experimental boundary conditions to enable precise numeric reproduction of the experimental results. The general capabilities of this new analytical tool for the investigation of reacting flows are demonstrated for a selected range of conditions, fuels, and applications. A detailed dataset for the well-known gaseous fuels, methane and ethylene, is provided and used to verify the experimental approach. Furthermore, application for liquid fuels and fuel components important for technical combustors like gas turbines and engines is demonstrated. Besides the detailed investigation of novel fuels and fuel components, the wide range of operation conditions gives access to extended combustion topics, such as super rich conditions at high temperature important for gasification processes, or the peroxy chemistry governing the low temperature oxidation regime. These demonstrations are accompanied by a first kinetic modeling approach, examining the opportunities for model validation purposes.

  8. Simulation of sea surface temperatures with the surface heat fluxes from an atmospheric circulation model

    OpenAIRE

    Karaca, Mehmet; MÜLLER, DETLEV

    2011-01-01

    The global fields of the surface heat fluxes for the December-February period are calculated with the UCLA atmospheric circulation model (ACM). This model operates on a global grid net. The planetary boundary layer (PBL), as the decisive subsystem for the surface fluxes, is parameterized in terms of its bulk properties. For several locations in the north Atlantic, the model heat fluxes are incorporated into the forcing of a simple ocean mixed-layer (OML) model. The OML-model uses a slight gen...

  9. Trifluoro methyl peroxynitrate (CF 3OONO 2): Temperature dependence of the UV absorption spectrum and atmospheric implications

    Science.gov (United States)

    Malanca, Fabio E.; Chiappero, Malisa S.; Argüello, Gustavo A.; Wallington, Timothy J.

    The ultraviolet absorption spectrum of gas phase CF 3OONO 2 has been measured over the wavelength range 200-340 nm at 233-300 K. Absorption cross-sections at wavelengths of 290-340 nm were found to increase significantly with increasing temperature. The UV spectra of CF 3C(O)Cl and CF 3C(O)F were measured and were consistent with previous work [Rattigan et al., 1993. Temperature-dependent absorption cross-sections of CF 3COCl, CF 3COF, CH 3COF, CCl 3CHO and CF 3COOH. Journal of Photochemistry and Photobiology A: Chemistry 73, 1-9]. Implications for the atmospheric chemistry of CF 3OONO 2 are discussed.

  10. Daily changes of radon concentration in soil gas under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Evelise G.; Oliveira, Arno Heeren de, E-mail: evelise.lara@gmail.com, E-mail: heeren@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Rocha, Zildete; Rios, Francisco Javier, E-mail: rochaz@cdtn.br, E-mail: javier@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    This work aims at relating the daily change in the radon concentration in soil gas in a Red Yellow Acrisol (SiBCS) under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity. The {sup 226}Ra, {sup 232}Th, U content and permeability were also performed. The measurements of radon soil gas were carried out by using an AlphaGUARD monitor. The {sup 226}Ra activity concentration was made by Gamma Spectrometry (HPGe); the permeability was carried out using the RADON-JOK permeameter and ICP-MS analysis to {sup 232}Th and U content. The soil permeability is 5.0 x 10{sup -12}, which is considered average. The {sup 226}Ra (22.2 ± 0.3 Bq.m{sup -3}); U content (73.4 ± 3.6 Bq.kg{sup -1}) and {sup 232}Th content (55.3 ± 4.0 Bq.kg{sup -1}) were considered above of average concentrations, according to mean values for soils typical (~ 35.0 Bq.kg{sup -1}) by UNSCEAR. The results showed a difference of 26.0% between the highest and the lowest concentration of radon in soil gas: at midnight (15.5 ± 1.0 kBq.m{sup -3}) and 3:00 pm, the highest mean radon concentration (21.0 ± 1.0 kBq.m{sup -3}). The room temperature and surface soil temperature showed equivalent behavior and the surface soil temperature slightly below room temperature during the entire monitoring time. Nevertheless, the relative humidity showed the highest cyclical behavior, showing a higher relationship with the radon concentration in soil gas. (author)

  11. Mean ocean temperature change over the last glacial transition based on atmospheric changes in heavy noble mixing ratios

    Science.gov (United States)

    Bereiter, Bernhard; Severinghaus, Jeff; Shackleton, Sarah; Baggenstos, Daniel; Kawamura, Kenji

    2016-04-01

    On paleo-climatic timescales heavy noble gases (Krypton and Xenon) are passively cycled through the atmosphere-ocean system without seeing any significant sink or source. Since the solubility in water of each gas species is characterized by a specific temperature dependency, mixing ratios in the atmosphere change with changing ocean temperatures. In this study, we use this fact to reconstruct mean global ocean temperatures (MOT) over the course of the last glacial transition based on measurements of trapped air in the WAIS Divide ice core. We analyzed 70 ice samples with a recently developed method which determines the isotopic ratios of N2, Ar, Kr (and in some cases also of Xe, though with less precision) and the elemental ratios of Kr/N2, Xe/N2 and Xe/Kr. We use the isotope ratios to correct the elemental ratios for gravitational enrichment in the firn column. The corrected elemental ratios are then used in a simple box model to reconstruct MOT. The three elemental ratio pairs are first interpreted as independent measures of MOT and then combined to a single "best-estimate" MOT record with an average uncertainty of 0.27°C. We find a clear link to Antarctic temperatures and a LGM-Holocene change in MOT of 2.4°C. This value is in good agreement with results from marine sediment cores (which, however, have an uncertainty of 1°C). Our record provides an unprecedented constrain on ocean heat uptake over the last glacial transition and therefore gives new insights in the mechanisms underlying long term ocean heat fluxes. To our knowledge, this is the first time that MOT has been reconstructed in such great detail.

  12. Global measurements of sea surface temperature, wind speed and atmospheric water content from satellite microwave radiometry

    Science.gov (United States)

    Njoku, E. G.; Swanson, L.

    1983-01-01

    The Scanning Multichannel Microwave Radiometer (SMMR) was launched on the Seasat and Nimbus 7 satellites in 1978. The SMMR has the ability to measure sea surface temperature and wind speed with the aid of microwaves. In addition, the instrument was designed to measure water vapor and cloud liquid water with better spatial resolution than previous microwave radiometers, and to make sea-ice measurements with higher precision. A description is presented of the results of global analyses of sea surface temperature, wind speed, water vapor, and cloud liquid water, taking into account data provided by the SMMR on the Seasat satellite. It is found that the SMMR data show good self-consistency, and can usefully measure global distributions of sea surface temperatures, surface winds, water vapor, and cloud liquid water.

  13. Synthesis of MIL-100(Fe at Low Temperature and Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    Jing Shi

    2013-01-01

    Full Text Available MIL-100(Fe, a mesoporous metal-organic framework (MOF, has a large BET specific surface area and pore volume with the presence of a significant amount of accessible Lewis acid metal sites upon dehydration. The structural characteristics of MIL-100(Fe make it a good candidate for potential applications in gas storage, separation, and heterogeneous catalysis. Mainly, this MOF is obtained by the hydrothermal synthesis in a Teflon-lined autoclave at high temperature (>150°C under static conditions. However, this method has several disadvantages such as high temperature, high (autogenous pressure, long time, and comparable low MOF yield. Therefore, development of a facile method for synthesis of MIL-100(Fe is vitally important for fundamental understanding and practical application. Herein, MIL-100(Fe is synthesized by a facile low-temperature (90% still could be achieved, suggesting that this simple and energy saving method has the potential to be used practically.

  14. Soil- and Atmosphere-Induced Plant Water Stress in Cotton as Inferred From Foliage Temperatures

    Science.gov (United States)

    Idso, S. B.; Reginato, R. J.; Farah, S. M.

    1982-08-01

    Foliage temperatures of cotton obtained by means of infrared thermometry, along with air wet and dry bulb temperature measurements, were used to investigate certain relationships existing between the water contents of soil and air and the ability of the crop to maintain transpiration at the potential rate. It was found that as soil water content is progressively depleted following an irrigation, departure from potential transpiration begins to occur at smaller and smaller values of air vapor pressure deficit in a regularly predictable fashion. It was also demonstrated that the plant water potential of cotton transpiring at the potential rate is a function of the air vapor pressure deficit and that the difference between this base value and the tension that develops under nonpotential conditions is a unique function of a newly developed plant water stress index. Finally, an example of the application of this foliage temperature-based index to evaluating the effects of an irrigation event is presented.

  15. Benzylammonium Thermometer Ions: Internal Energies of Ions Formed by Low Temperature Plasma and Atmospheric Pressure Chemical Ionization

    Science.gov (United States)

    Stephens, Edward R.; Dumlao, Morphy; Xiao, Dan; Zhang, Daming; Donald, William A.

    2015-12-01

    The extent of internal energy deposition upon ion formation by low temperature plasma and atmospheric pressure chemical ionization was investigated using novel benzylammonium thermometer ions. C-N heterolytic bond dissociation enthalpies of nine 4-substituted benzylammoniums were calculated using CAM-B3LYP/6-311++G(d,p), which was significantly more accurate than B3LYP/6-311++G(d,p), MP2/6-311++G(d,p), and CBS-QB3 for calculating the enthalpies of 20 heterolytic dissociation reactions that were used to benchmark theory. All 4-substituted benzylammonium thermometer ions fragmented by a single pathway with comparable dissociation entropies, except 4-nitrobenzylammonium. Overall, the extent of energy deposition into ions formed by low temperature plasma was significantly lower than those formed by atmospheric pressure chemical ionization under these conditions. Because benzylamines are volatile, this new suite of thermometer ions should be useful for investigating the extent of internal energy deposition during ion formation for a wide range of ionization methods, including plasma, spray and laser desorption-based techniques.

  16. Benzylammonium Thermometer Ions: Internal Energies of Ions Formed by Low Temperature Plasma and Atmospheric Pressure Chemical Ionization.

    Science.gov (United States)

    Stephens, Edward R; Dumlao, Morphy; Xiao, Dan; Zhang, Daming; Donald, William A

    2015-12-01

    The extent of internal energy deposition upon ion formation by low temperature plasma and atmospheric pressure chemical ionization was investigated using novel benzylammonium thermometer ions. C-N heterolytic bond dissociation enthalpies of nine 4-substituted benzylammoniums were calculated using CAM-B3LYP/6-311++G(d,p), which was significantly more accurate than B3LYP/6-311++G(d,p), MP2/6-311++G(d,p), and CBS-QB3 for calculating the enthalpies of 20 heterolytic dissociation reactions that were used to benchmark theory. All 4-substituted benzylammonium thermometer ions fragmented by a single pathway with comparable dissociation entropies, except 4-nitrobenzylammonium. Overall, the extent of energy deposition into ions formed by low temperature plasma was significantly lower than those formed by atmospheric pressure chemical ionization under these conditions. Because benzylamines are volatile, this new suite of thermometer ions should be useful for investigating the extent of internal energy deposition during ion formation for a wide range of ionization methods, including plasma, spray and laser desorption-based techniques. Graphical Abstract ᅟ.

  17. Numerical study of a buoyant plume from a multi-flue stack into a variable temperature gradient atmosphere.

    Science.gov (United States)

    Velamati, Ratna Kishore; Vivek, M; Goutham, K; Sreekanth, G R; Dharmarajan, Santosh; Goel, Mukesh

    2015-11-01

    Air pollution is one of the major global hazards and industries have been one of its major contributors. This paper primarily focuses on analyzing the dispersion characteristics of buoyant plumes of the pollutant released from a multi-flue vertical stack into a variable temperature gradient atmosphere (α) in a constant-velocity cross wind using two stack configurations-inline and parallel. The study is conducted for different Froude numbers, Fr = 12.64, 9.55, and 8.27. The atmospheric temperature gradients considered for the study are 0, +1, +1.5, and +2 K/100 m. The numerical study is done using the commercial computational fluid dynamics (CFD) code FLUENT. The effects of stack configuration, α, and Fr on the plume characteristics are presented. It is observed that the plume rises higher and disperses over a larger area with the inline configuration due to better mixing and shielding effect. With higher α, it is seen that the plume rises initially and then descends due to variation of the buoyant force. The plume rise initially is strongly influenced by the momentum of the jet, and as it moves downstream, it is influenced by the cooling rate of the plume. Furthermore, the plume rises higher and disperses over a larger area with a decrease in Fr. PMID:26099599

  18. Model of a surface-wave discharge at atmospheric pressure with a fixed profile of the gas temperature

    Science.gov (United States)

    Nikovski, M.; Kiss'ovski, Zh; Tatarova, E.

    2016-03-01

    We present a 3D model of a surface-wave-sustained discharge at 2.45 GHz at atmospheric pressure. A small plasma source creates a plasma column in a dielectric tube and a plasma torch is observed above the top. The plasma parameters and the axial profile of the gas temperature are significantly changed in the presence of the substrate above the plasma torch. The Boltzmann equation for electrons under the local approximation is solved, together with the heavy particle balance equations at a fixed axial profile of the gas temperature. The model of this finite length plasma column includes also the dispersion relation of azimuthally-symmetric surface waves. A detailed collisional-radiative model is also implemented for argon discharge at atmospheric pressure, which includes 21 rate balance equations for excited Ar atoms [(Ar(1s5-1s2), Ar(2p10-2p1), Ar(2s3d), Ar(3p)], for positive Ar+ and Ar2 + ions and for excited molecules. The changes in the EEDF shape and the mean electron energy along the plasma column are investigated and the axial structures of the discharge and plasma parameters are obtained.

  19. Degradation of metaflumizone in soil: impact of varying moisture, light, temperature, atmospheric CO2 level, soil type and soil sterilization.

    Science.gov (United States)

    Chatterjee, Niladri Sekhar; Gupta, Suman; Varghese, Eldho

    2013-01-01

    Soil is a major sink for the bulk of globally used pesticides. Hence, fate of pesticides in soil under the influence of various biotic and abiotic factors becomes important for evaluation of stability and safety. This paper presents the impact of varying moisture, light, temperature, atmospheric CO(2) level, soil type and soil sterilization on degradation of metaflumizone, a newly registered insecticide in India. Degradation of metaflumizone in soil followed the first order reaction kinetics and its half life values varied from ~20 to 150 d. Under anaerobic condition, degradation of metaflumizone was faster (t(½) 33.4 d) compared to aerobic condition (t(½) 50.1 d) and dry soil (t(½) 150.4 d). Under different light exposures, degradation was the fastest under UV light (t(½) 27.3 d) followed by Xenon light (t(½) 43 d) and dark condition (t(½) 50.1 d). Degradation rate of metaflumizone increased with temperature and its half life values ranged from 30.1 to 100.3d. Elevated atmospheric CO(2) level increased the degradation in soil (t(½) 20.1-50.1 d). However, overall degradation rate was the fastest at 550 ppm atmospheric CO(2) level, followed by 750 ppm and ambient level (375 ppm). Degradation of metaflumizone was faster in Oxisol (pH 5.2, Total Organic Carbon 1.2%) compared to Inceptisol (pH 8.15, TOC 0.36%). In sterile soil, only 5% dissipation of initial concentration was observed after 90 d of sampling. Under various conditions, 4-cyanobenzoic acid (0.22-1.86 mg kg(-1)) and 4-trifluoromethoxy aniline (0.21-1.23 mg kg(-1)) were detected as major degradation products.

  20. Coupling between atmospheric CO2 and temperature during the onset of the Little Ice Age

    NARCIS (Netherlands)

    Hoof, T.B. van

    2004-01-01

    Present day global warming is primarily caused by the greenhouse effect of the increased CO2 emissions since the onset of the industrial revolution. A coupling between temperature and the greenhouse gas CO2 has also been observed in several ice-core records on a glacial-interglacial timescale as we

  1. Screen level temperature increase due to higher atmospheric carbon dioxide in calm and windy nights revisited

    NARCIS (Netherlands)

    Steeneveld, G.J.; Holtslag, A.A.M.; McNider, R.T.; Pielke sr., R.A.

    2011-01-01

    Long-term surface observations over land have shown temperature increases during the last century, especially during nighttime. Observations analyzed by Parker [2004] show similar long-term trends for calm and windy conditions at night, and on basis of this it was suggested that the possible effect

  2. The synthesis of [2-13C]2-nitropropane at room temperature and at atmospheric pressure

    NARCIS (Netherlands)

    Jacquemijns M; Zomer G

    1990-01-01

    In this report the synthesis of [2-13C]2-nitropropane at room temperature is described. [2-13C]Acetone was converted into the oxime with hydroxy hydrochloridelamine and sodium carbonate. Treatment with hypobromic acid resulted in 2-13C]2-bromo-2-nitropropane. Hydrogenation with sodium borohydride

  3. Response of atmospheric ground level temperatures to changes in the total solar irradiance

    CERN Document Server

    Erlykin, Anatoly

    2015-01-01

    The attribution of part of global warming to changes in the total solar irradiance (TSI) is an important topic which is not, yet, fully understood. Here, we examine the TSI induced temperature (T) changes on a variety of time scales, from one day to centuries and beyond, using a variety of assumptions. Also considered is the latitude variation of the T-TSI correlations, where it appears that over most of the globe there is a small increase in the sensitivity of temperature to TSI in time. It is found that the mean global sensitivity (alpha)measured in K(Wm-2)-1 varies from about 0.003 for 1 day, via 0.05 for 11-years to about 0.2 for decades to centuries. We conclude that mean global temperature changes related to TSI are not significant from 1975 onwards. Before 1975, when anthropogenic gases were less important, many of the temperature changes can be attributed to TSI variations. Over much longer periods of time, from Kyear to Myear, the TSI changes are more efficient still, the sensitivity alpha increasing...

  4. Effects of Modified Atmosphere Packaging, Food Life Extenders and Temperature on the Shelf Life of Ready-Made Dishes.

    Science.gov (United States)

    Sato, Jun; Maenishi, Takuya; Saito, Yuki; Masuda, Toshiro; Kadotani, Naoki; Kozakai, Hiroshi; Ito, Masanori

    2016-01-01

    The combined effect of several microbial control factors including gas barrier of containers, modified atmosphere packaging, food life extenders and storage temperature was discussed in order to determine the possibility for improving the shelf life for hamburger steak and deepfried chicken, representative ready-made dishes sold at convenience stores in Japan. Multiple measures including cold storage were effective in improving the shelf life of ready-made dishes. It was also suggested that storage tests for ready-made dishes should be conducted at 10℃, a practical temperature, to confirm the storable period, as well as at 15℃, an adequate abuse temperature, to confirm the effects of various microbial control factors. In the present study, the test group 4 (nitrogen + barrier containers + pH modifier) performed most favorably at both temperatures, indicating the efficacy of multiple means including "cold storage" in improving the shelf life (extending the consume-by date) of ready-made dishes. All strains isolated from the tested hamburger steak and deep-fried chicken were common food contaminant bacterial species. PMID:27009505

  5. NO density and gas temperature measurements in atmospheric pressure nanosecond repetitively pulsed (NRP) discharges by Mid-IR QCLAS

    Science.gov (United States)

    Simeni Simeni, Marien; Stancu, Gabi-Daniel; Laux, Christophe

    2014-10-01

    Nitric oxide is a key species for many processes: in combustion, in human skin physiology... Recently, NO-ground state absolute density measurements produced by atmospheric pressure NRP discharges were carried out in air as a function of the discharge parameters, using Quantum Cascade Laser Absorption Spectroscopy. These measurements were space averaged and performed in the post-discharge region in a large gas volume. Here we present radial profiles of NO density and temperature measured directly in the discharge for different configurations. Small plasma volume and species densities, high temperature and EM noise environment make the absorption diagnostic challenging. For this purpose the QCLAS sensitivity was improved using a two-detector system. We conducted lateral absorbance measurements with a spatial resolution of 300 μm for two absorption features at 1900.076 and 1900.517 cm-1. The radial temperature and NO density distributions were obtained from the Abel inverted lateral measurements. Time averaged NO densities of about 1.E16 cm-3 and gas temperature of about 1000K were obtained in the center of the discharge. PLASMAFLAME Project (Grant No ANR-11-BS09-0025).

  6. Photodissociation in the atmosphere of Mars - Impact of high resolution, temperature-dependent CO2 cross-section measurements

    Science.gov (United States)

    Anbar, A. D.; Allen, M.; Nair, H. A.

    1993-01-01

    We have investigated the impact of high resolution, temperature-dependent CO2 cross-section measurements, reported by Lewis and Carver (1983), on calculations of photodissociation rate coefficients in the Martian atmosphere. We find that the adoption of 50 A intervals for the purpose of computational efficiency results in errors in the calculated values for photodissociation of CO2, H2O, and O2 which are generally not above 10 percent, but as large as 20 percent in some instances. These are acceptably small errors, especially considering the uncertainties introduced by the large temperature dependence of the CO2 cross section. The inclusion of temperature-dependent CO2 cross sections is shown to lead to a decrease in the diurnally averaged rate of CO2 photodissociation as large as 33 percent at some altitudes, and increases of as much as 950 percent and 80 percent in the photodissociation rate coefficients of H2O and O2, respectively. The actual magnitude of the changes depends on the assumptions used to model the CO2 absorption spectrum at temperatures lower than the available measurements, and at wavelengths longward of 1970 A.

  7. Effects of Modified Atmosphere Packaging, Food Life Extenders and Temperature on the Shelf Life of Ready-Made Dishes.

    Science.gov (United States)

    Sato, Jun; Maenishi, Takuya; Saito, Yuki; Masuda, Toshiro; Kadotani, Naoki; Kozakai, Hiroshi; Ito, Masanori

    2016-01-01

    The combined effect of several microbial control factors including gas barrier of containers, modified atmosphere packaging, food life extenders and storage temperature was discussed in order to determine the possibility for improving the shelf life for hamburger steak and deepfried chicken, representative ready-made dishes sold at convenience stores in Japan. Multiple measures including cold storage were effective in improving the shelf life of ready-made dishes. It was also suggested that storage tests for ready-made dishes should be conducted at 10℃, a practical temperature, to confirm the storable period, as well as at 15℃, an adequate abuse temperature, to confirm the effects of various microbial control factors. In the present study, the test group 4 (nitrogen + barrier containers + pH modifier) performed most favorably at both temperatures, indicating the efficacy of multiple means including "cold storage" in improving the shelf life (extending the consume-by date) of ready-made dishes. All strains isolated from the tested hamburger steak and deep-fried chicken were common food contaminant bacterial species.

  8. Impact of temperature field inhomogeneities on the retrieval of atmospheric species from MIPAS IR limb emission spectra

    Directory of Open Access Journals (Sweden)

    M. Kiefer

    2010-04-01

    Full Text Available We examine volume mixing ratios (vmr retrieved from limb emission spectra recorded with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS. In level 2 (L2 data products of three different retrieval processors, which perform one dimensional (1-D retrievals, we find significant differences between species' profiles from ascending and descending orbit parts. The relative differences vary systematically with time of the year, latitude, and altitude. In the lower stratosphere their monthly means can reach maxima of 20% for CFC-11, CFC-12, HNO3, H2O, 10% for CH4 and N2O. Relative differences between monthly means of 1-D retrieval results and of the true atmospheric state can be expected to reach half of these percentage values, while relative differences in single vmr profiles might well exceed those numbers. Often there are no physical or chemical reasons for these differences, so they are an indicator for a problem in the data processing. The differences are generally largest at locations where the meridional temperature gradient of the atmosphere is strong. On the contrary, when performing the retrieval with a tomographic two dimensional (2-D retrieval, L2 products generally do not show these differences. This implies that inhomogeneities in the temperature field, and possibly in the species' fields, which are accounted for in the 2-D algorithm and not in standard 1-D processors, may cause significant deviations in the results. Inclusion of an externally given adequate temperature gradient in the forward model of a 1-D processor helps to reduce the observed differences. However, only the full tomographic approach is suitable to resolve the horizontal inhomogeneities. Implications for the use of the 1-D data, e.g. for validation, are discussed. The dependence of the ascending/descending differences on the observation strategy suggests that this problem is to be expected to affect in

  9. Geophysical validation of temperature retrieved by the ESA processor from MIPAS/ENVISAT atmospheric limb-emission measurements

    Directory of Open Access Journals (Sweden)

    M. Ridolfi

    2007-08-01

    Full Text Available The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS has been operating since March 2002 onboard of the ENVIronmental SATellite of the European Space Agency (ESA. The high resolution (0.035 cm−1 full width half maximum, unapodized limb-emission measurements acquired by MIPAS in the first two years of operation have very good geographical and temporal coverage and have been re-processed by ESA with the most recent versions (4.61 and 4.62 of the inversion algorithms. The products of this processing chain are pressures at the tangent points and geolocated profiles of temperature and of the volume mixing ratios of six key atmospheric constituents: H2O, O3, HNO3, CH4, N2O and NO2. As for all the measurements made with innovative instruments and techniques, this data set requires a thorough validation. In this paper we present a geophysical validation of the temperature profiles derived from MIPAS measurements by the ESA retrieval algorithm. The validation is carried-out by comparing MIPAS temperature with correlative measurements made by radiosondes, lidars, in-situ and remote sensors operated either from the ground or stratospheric balloons.

    The results of the intercomparison indicate that the bias of the MIPAS profiles is generally smaller than 1 or 2 K depending on altitude. Furthermore we find that, especially at the edges of the altitude range covered by the MIPAS scan, the random error estimated from the intercomparison is larger (typically by a factor of two to three than the corresponding estimate derived on the basis of error propagation.

    In this work we also characterize the discrepancies between MIPAS temperature and the temperature fields resulting from the analyses of the European Centre for Medium-range Weather Forecasts (ECMWF. The bias and the standard deviation of these discrepancies are consistent with those obtained when

  10. Geophysical validation of temperature retrieved by the ESA processor from MIPAS/ENVISAT atmospheric limb-emission measurements

    Directory of Open Access Journals (Sweden)

    M. Ridolfi

    2007-04-01

    Full Text Available The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS has been operating since March 2002 onboard of the ENVIronmental SATellite of the European Space Agency (ESA. The high resolution (0.035 cm−1 limb-emission measurements acquired by MIPAS in the first two years of operation have very good geographical and temporal coverage and have been re-processed by ESA with the most recent versions (4.61 and 4.62 of the inversion algorithms. The products of this processing chain are geolocated profiles of temperature and of the volume mixing ratios of six key atmospheric constituents: H2O, O3, HNO3, CH4, N2O and NO2. As for all the measurements made with innovative instruments and techniques, this data set requires a thorough validation. In this paper we present a geophysical validation of the temperature profiles derived from MIPAS measurements by the ESA retrieval algorithm. The validation is carried-out by comparing MIPAS temperature with correlative measurements made by radiosondes, lidars, in-situ and remote sensors operated either from the ground or stratospheric balloons.

    The results of the intercomparison indicate that the bias of the MIPAS profiles is generally smaller than 1 or 2 K depending on altitude. Furthermore we find that, especially at the edges of the altitude range covered by the MIPAS scan, the random error estimated from the intercomparison is larger (typically by a factor of two to three than the corresponding estimate derived on the basis of error propagation.

    In this work we also characterize the discrepancies between MIPAS temperature and the temperature fields resulting from the analyses of the European Centre for Medium-range Weather Forecasts (ECMWF. The bias and the standard deviation of these discrepancies are consistent with those obtained when comparing MIPAS to correlative measurements; however, in this case the

  11. Simultaneous measurement of Ni-Al particle size, velocity, and temperature in atmospheric thermal plasmas

    International Nuclear Information System (INIS)

    A technique for simultaneously measuring particle size, velocity, and temperature has been applied to the in-flight characterization of a Ni--Al particles sprayed in a 28 kW plasma torch. The radial distribution of particle size, velocity, temperature and particle concentration were obtained at stand off distances between 63.5 and 88.9 mm. These measurements and their relationship to the characteristics of the resulting coating are discussed. Injection geometry dependent particle sizing and an apparant fracturing of the original particles into smaller particles was observed. A significant fraction of the largest particles observed did not appear to the molten. Particle behavior was found to be relatively insensitive to gas mixture and flow rate. 1 ref., 8 figs

  12. Rheological behavior of Shengli coal-solvent slurry at low-temperatures and atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    WANG Yong-gang; YAN Yan; GUO Xiang-kun; Xu De-ping

    2009-01-01

    We report the results from systematic studies of Shengli lignite coal-solvent slurries. Solvent type, temperature, coal to solvent ratio, particle granularity, shear rate and shear time were investigated. The viscosity of the solvents is time independent. However, the slurries are thixotropic. A change from pseudo-plastic to Newtonian behavior occurs as the temperature, or as the solvent to coal ratio, increases. The solvent used in the slurry affects the point at which the theology changes from pseudo-plastic to Newtonian. The REC slurry changes at 1 : 1.2 coal to solvent ratio and at 40 ℃. The HAR slurry changes at a 1:1.5 ratio and at 60 ℃. The theology of the slurries is pseudo-plastic at low shear rates but Newtonian at high shear rates.

  13. The temperature structure and pressure balance of magnetic loops in active regions. [in solar atmosphere

    Science.gov (United States)

    Foukal, P.

    1975-01-01

    EUV observations show many active region loops in lines formed at temperatures between 10,000 and 2,000,000 K. The brightest loops are associated with flux tubes leading to the umbrae of sunspots. It is shown that the high visibility of certain loops in transition region lines is due principally to a sharp radial decrease of temperature to chromospheric values toward the loop axis. The plasma density of these cool loops is not significantly greater than in the hot gas immediately surrounding it. Consequently, the internal gas pressure of the cool material is clearly lower. The hot material immediately surrounding the cool loops is generally denser than the external corona by a factor 3-4. When the active region is examined in coronal lines, this hot high pressure plasma shows up as loops that are generally parallel to the cool loops but significantly displaced laterally.

  14. A comparison of atmospheric temperature over China between radiosonde observations and multiple reanalysis datasets

    Science.gov (United States)

    Guo, Yanjun; Zhang, Siqi; Yan, Jinghui; Chen, Zhe; Ruan, Xin

    2016-04-01

    The quality controlled (RAW) and homogenized (ADJ) radiosonde temperatures within 850-30 hPa collected at 118 stations in China are compared, on a monthly mean basis, with the temperatures extracted from 8 reanalysis datasets (REA) including NCEP-1, NCEP-2, ERA-40 (ECMWF 45-yr Reanalysis), ERA-Interim, JRA-55 (Japanese 55-yr Reanalysis), 20CR (20th Century Reanalysis), MERRA (Modern Era Retrospective-Analysis), and CFSR (Climate Forecast System Reanalysis). Average differences, correlations, standard deviations, and linear trends among RAW, ADJ, and REA for the period 1981-2010 are analyzed. The results reveal significant inhomogeneity in the time series of RAW radiosonde temperature in China; an overall negative adjustment was thus employed to obtain the ADJ temperatures, and the effect of the negative adjustment is the most significant within 200-100 hPa. Such a homogenization process has removed the system errors in RAW, possibly caused by radiosonde instrument changes and observation system upgrades. Hence, the correlation is higher between ADJ and REA than that between RAW and REA. The mean difference between ADJ and REA is about 1℃ during 1981-2010, while REA are mostly cooler in the troposphere and warmer in the stratosphere than ADJ; nonetheless, they have a significant high and positive correlation and their annual variability is notably consistent. Furthermore, the linear trends in REA and ADJ both demonstrate warming in the lower-mid troposphere and cooling in the mid stratosphere, with large uncertainties found in the upper troposphere and lower stratosphere. In general, ERA-Interim, JRA-55, and MERRA are more consistent with ADJ than other reanalysis datasets.

  15. Incipient corrosion behavior of Haynes 230 under a controlled reducing atmosphere at high temperatures

    Science.gov (United States)

    Tung, Hsiao-Ming; Stubbins, James F.

    2012-08-01

    In situ thermogravimetry analysis (TGA) was used to investigate the incipient corrosion behavior of alloy 230 exposed under a reducing environment in a temperature range of 850-1000 °C. Both oxidation and loss of alloying elements of alloy 230 were observed to occur concurrently in these conditions. The surface oxide which formed on the substrate does not appear to be as effective in providing a protective layer during the incipient corrosion period.

  16. The synthesis of [2-13C]2-nitropropane at room temperature and at atmospheric pressure

    OpenAIRE

    Jacquemijns M; Zomer G

    1990-01-01

    In this report the synthesis of [2-13C]2-nitropropane at room temperature is described. [2-13C]Acetone was converted into the oxime with hydroxy hydrochloridelamine and sodium carbonate. Treatment with hypobromic acid resulted in 2-13C]2-bromo-2-nitropropane. Hydrogenation with sodium borohydride gave [2-13C]2-nitropropane in 14,3% overall yield.

  17. A 6U CubeSat Constellation for Atmospheric Temperature and Humidity Sounding

    Science.gov (United States)

    Padmanabhan, Sharmila; Brown, Shannon; Kangaslahti, Pekka; Cofield, Richard; Russell, Damon; Stachnik, Robert; Steinkraus, Joel; Lim, Boon

    2013-01-01

    We are currently developing a 118/183 GHz sensor that will enable observations of temperature and precipitation profiles over land and ocean. The 118/183 GHz system is well suited for a CubeSat deployment as 10cm antenna aperture provides sufficiently small footprint sizes (is approx. 25km). This project will enable low cost, compact radiometer instrumentation at 118 and 183 GHz that would fit in a 6U CubeSat with the objective of mass-producing this design to enable a suite of small satellites to image the key geophysical parameters that are needed to improve prediction of extreme weather events. We will take advantage of past and current technology developments at JPL viz. HAMSR (High Altitude Microwave Scanning Radiometer), Advanced Component Technology (ACT'08) to enable low-mass and low-power high frequency airborne radiometers. The 35 nm InP enabling technology provides significant reduction in power consumption (Low Noise Amplifier + Mixer Block consumes 24 mW). In this paper, we will describe the design and implementation of the 118 GHz temperature sounder and 183 GHz humidity sounder instrument on the 6U CubeSat. In addition, a summary of radiometer calibration and retrieval techniques of the temperature and humidity will be discussed. The successful demonstration of this instrument on the 6U CubeSat would pave the way for the development of a constellation consisting of suite of these instruments. The proposed constellation of these 6U CubeSat radiometers would allow sampling of tropospheric temperature and humidity with fine temporal (on the order of minutes) and spatial resolution (is approx. 25 km).

  18. Coupling between atmospheric CO2 and temperature during the onset of the Little Ice Age

    OpenAIRE

    Hoof, T.B. van

    2004-01-01

    Present day global warming is primarily caused by the greenhouse effect of the increased CO2 emissions since the onset of the industrial revolution. A coupling between temperature and the greenhouse gas CO2 has also been observed in several ice-core records on a glacial-interglacial timescale as well as on a millennial timescale during the glacials. In marked contrast, no significant ice-derived CO2 fluctuations occur on centennial time scales contemporaneously with well-documented cooling ev...

  19. Solar cycle variability in mean thermospheric composition and temperature induced by atmospheric tides

    Science.gov (United States)

    Jones, M.; Forbes, J. M.; Hagan, M. E.

    2016-06-01

    In this paper we demonstrate that dissipation of upward propagating tides produces significant changes in the mean temperature of the thermosphere, ranging from +19 K at solar minimum to -15 K at solar maximum in the equatorial region. Our methodology consists of measuring the differential response of the thermosphere-ionosphere-electrodynamics general circulation model (TIE-GCM) under solar minimum and solar maximum conditions to constant tidal forcing at its 97 km lower boundary, as specified by the observationally based Climatological Tidal Model of the Thermosphere. Diagnosis of the model reveals that these changes are mainly driven by 5.3 μm nitric oxide (NO) cooling, which more efficiently cools the thermosphere at solar maximum. The main role of the tides is to modify the mean molecular oxygen densities ([O2]) through tidal-induced advective transport, which then lead to changes in NO densities through oxygen-nitrogen chemistry. Through tidal-induced changes in temperature and O, O2, and N2 densities, effects on the ionosphere are also quite substantial; tidal-induced modifications to zonal-mean F region peak electron densities (NmF2) are of order -10% at solar maximum and -30% at solar minimum in the equatorial region. Our results introduce an additional consideration when attributing long-term changes in thermospheric temperature and electron densities to CO2 cooling effects alone; that is, dissipation of upward propagating tides may constitute an additional element of global change in the ionosphere-thermosphere (IT) system.

  20. CFCl3 (CFC-11): UV Absorption Spectrum Temperature Dependence Measurements and the Impact on Atmospheric Lifetime Uncertainty

    Science.gov (United States)

    McGillen, M.; Fleming, E. L.; Jackman, C. H.; Burkholder, J. B.

    2013-12-01

    CFCl3 (CFC-11) is both a major ozone-depleting substance and a potent greenhouse gas that is removed primarily via stratospheric UV photolysis. Uncertainty in the temperature dependence of its UV absorption spectrum is a significant contributing factor to the overall uncertainty in its global lifetime and, thus, model calculations of stratospheric ozone recovery and climate change. In this work, the CFC-11 UV absorption spectrum was measured over a range of wavelength (184.95-230 nm) and temperature (216-296 K). We report a spectrum temperature dependence that is less than currently recommended for use in atmospheric models. The impact on its atmospheric lifetime was quantified using the NASA Goddard Space Flight Center 2-D coupled chemistry-radiation-dynamics model and the spectrum parameterization developed in this work. The modeled global annually averaged lifetime was 58.1 × 0.7 years (2σ uncertainty due solely to the spectrum uncertainty). The lifetime is slightly reduced and the uncertainty significantly reduced from that obtained using current UV spectrum recommendations. CFCl 3 (CFC-11) 2-D model results: Left: Global annually averaged loss rate coefficient (local lifetime) and photolysis and reaction contributions (see legend). Middle: Molecular loss rate and uncertainty limits; the slow and fast profiles were calculated using the 2σ uncertainty estimates in the CFC-11 UV absorption spectrum from this work. Right: CFC-11 concentration profile. CFC-11 loss process contribution to the overall local lifetime uncertainty (2σ) calculated using the 2-D model (see text). Left: Results obtained from this work. Right: Results obtained using model input from Sander et al. [2011] and updates in SPARC [2013].

  1. Effects of temperature and other atmospheric conditions on long-term gaseous mercury observations in the Arctic

    Directory of Open Access Journals (Sweden)

    A. S. Cole

    2009-12-01

    Full Text Available Gaseous elemental mercury (GEM measurements at Alert, Canada, from 1995 to 2007 were analyzed for statistical time trends and for correlations with meteorological and climate data. A significant decreasing trend in annual GEM concentration is reported at Alert, with an estimated slope of −0.0086 ng m−3 yr−1 (−0.6% yr−1 over this 13-year period. It is shown that there has been a shift in the month of minimum mean GEM concentration from May to April due to a change in the timing of springtime atmospheric mercury depletion events (AMDEs. These AMDEs are found to decrease with increasing local temperature within each month, both at Alert and at Amderma, Russia. These results agree with the temperature dependence suggested by previous experimental results and theoretical kinetic calculations and highlight the potential for changes in Arctic mercury chemistry with climate. A correlation between total monthly AMDEs at Alert and the Polar/Eurasian Teleconnection Index was observed only in March, perhaps due to higher GEM inputs in early spring in those years with a weak polar vortex. A correlation of AMDEs at Alert with wind direction supports the origin of mercury depletion events over the Arctic Ocean, in agreement with a previous trajectory study of ozone depletion events. Interannual variability in total monthly depletion event frequency at Alert does not appear to correlate significantly with total or first-year northern hemispheric sea ice area or with other major teleconnection patterns. Nor do AMDEs at either Alert or Amderma correlate with local wind speed, as might be expected if depletion events are sustained by stable, low-turbulence atmospheric conditions. The data presented here – both the change in timing of depletion events and their relationship with temperature – can be used as additional constraints to improve the ability of global models to predict the cycling and deposition of mercury

  2. Surface treatment of a titanium implant using low temperature atmospheric pressure plasmas

    Science.gov (United States)

    Lee, Hyun-Young; Tang, Tianyu; Ok, Jung-Woo; Kim, Dong-Hyun; Lee, Ho-Jun; Lee, Hae June

    2015-09-01

    During the last two decades, atmospheric pressure plasmas(APP) are widely used in diverse fields of biomedical applications, reduction of pollutants, and surface treatment of materials. Applications of APP to titanium surface of dental implants is steadily increasing as it renders surfaces wettability and modifies the oxide layer of titanium that hinders the interaction with cells and proteins. In this study, we have treated the titanium surfaces of screw-shaped implant samples using a plasma jet which is composed of a ceramic coaxial tube of dielectrics, a stainless steel inner electrode, and a coper tube outer electrode. The plasma ignition occurred with Ar gas flow between two coaxial metal electrodes and a sinusoidal bias voltage of 3 kV with a frequency of 20 kHz. Titanium materials used in this study are screw-shaped implants of which diameter and length are 5 mm and 13 mm, respectively. Samples were mounted at a distance of 5 mm below the plasma source, and the plasma treatment time was set to 3 min. The wettability of titanium surface was measured by the moving speed of water on its surface, which is enhanced by plasma treatment. The surface roughness was also measured by atomic force microscopy. The optimal condition for wettability change is discussed.

  3. The influence of atmospheric blocking on extreme winter minimum temperatures in North America

    Science.gov (United States)

    Whan, Kirien; Zwiers, Francis; Sillmann, Jana

    2016-04-01

    Regional climate models (RCMs) are the primary source of high-resolution climate projections and it is of crucial importance to evaluate their ability to simulate extreme events under current climate conditions. Many extreme events are influenced by circulation features that occur outside, or on the edges of, RCM domains. Thus it is of interest to know whether such dynamically controlled aspects of extremes are well represented by RCMs. This study assesses the relationship between upstream blocking and cold temperature extremes over North America in observations, reanalysis products (ERA-Interim, NARR) and RCMs (CanRCM4, CRCM5, HIRHAM5, RCA4). Generalized extreme value distributions were fitted to winter minimum temperature (TNn) incorporating blocking frequency (BF) as a covariate, which has a significant influence on TNn. The magnitude of blocking influence in the RCMs is consistent with observations but the spatial extent varies. CRCM5 and HIRHAM5 reproduce the pattern of influence best compared to observations. CanRCM4 and RCA4 capture the influence of blocking in British Columbia and the northeastern United States but the extension of influence that is seen in observations and reanalysis, into the southern United States is not evident. The difference in the 20-year return value (20RV) of TNn between high and low BF indicates that blocking is associated with a decrease of up to 15°C in the 20RV over the majority of the United States and in western Canada. In northern North America the difference in the 20RV is positive as blocking is associated with warmer temperatures. The 20RVs are generally simulated well by the RCMs.

  4. Oxidation characteristics of nickel-base superalloys at high temperature in air and helium atmospheres

    International Nuclear Information System (INIS)

    Nickel-base superalloys are considered as materials for piping and structural materials in a very high temperature gas cooled reactor (VHTR). They are subjected to the environmental degradation caused by a continuous process for oxidation due to small amount of impurities in He coolant during long term operation. In the present study, the oxidation behaviors of several nickel-base superalloys such as Alloy-617, Haynes-214 and Haynes-230 in particular, were studied at the temperature of 900 and 1100 C degrees in air, and in the high purity He environment. Oxide layers were analyzed by SEM (Scanning Electron Microscope) and EDX (Energy Dispersive X-ray analysis). The differences in oxidation behaviors of these alloys were mainly caused by different protective oxide layers on surface. In the case of Alloy-617 and Haynes-230, Cr2O3 layer formed on the surface which is not stable at 1100 C degrees. Therefore, the weight increased significantly due to oxidation at the initial stage, which followed by a decrease due to the scaling and volatilization of Cr2O3 layer. On the other hand, since Haynes-214 has mainly Al2O3 oxide layer on surface which is more stable and has more dense structure at higher temperature, the weight gain eventually reaches to parabolic. Microstructural characteristics of internal carbides and carbide depletion zone were analyzed. With oxidation time, continuous grain boundary carbides of M23C6 type were getting thin or it disappeared partially. Especially, carbides on grain boundary disappeared entirely below oxide layer (carbide depletion zone). It was getting wide with oxidation time. For Haynes-214, the size of carbide depletion zone was smaller than other alloys because Al2O3 layer acted as a diffusion layer prevented effectively the penetration of oxygen into base metal. (authors)

  5. Atmospheric pollen season in Zagreb (Croatia) and its relationship with temperature and precipitation

    Science.gov (United States)

    Peternel, Renata; Srnec, Lidija; Čulig, Josip; Zaninović, Ksenija; Mitić, Božena; Vukušić, Ivan

    . The number of individuals allergic to plant pollen has recently been on a constant increase, especially in large cities and industrial areas. Therefore, monitoring of airborne pollen types and concentrations during the pollen season is of the utmost medical importance. The research reported in this paper aims to determine the beginning, course and end of the pollen season for the plants in the City of Zagreb, to identify allergenic plants, and to assess the variation in airborne pollen concentration as a function of temperature and precipitation changes for the year 2002. A volumetric Hirst sampler was used for airborne pollen sampling. Qualitative and quantitative pollen analysis was performed under a light microscope (magnification ×400). In the Zagreb area, 12 groups of highly allergenic plants (alder, hazel, cypress, birch, ash, hornbeam, grasses, elder, nettles, sweet chestnut, artemisia and ambrosia) were identified. Birch pollen predominated in spring, the highest concentrations being recorded in February and March. Grass pollen prevailed in May and June, and pollen of herbaceous plants of the genus Urtica (nettle) and of ambrosia in July, August and September. Air temperature was mostly higher or considerably higher than the annual average in those months, which resulted in a many days with high and very high airborne pollen concentrations. The exception was April, when these concentrations were lower because of high levels of precipitation. This also held for the first half of August and the second half of September. Pollen-sensitive individuals were at high risk from February till October because of the high airborne pollen concentrations, which only showed a transient decrease when the temperature fell or there was precipitation.

  6. Retrieval of temperature profiles from CHAMP for climate monitoring: intercomparison with Envisat MIPAS and GOMOS and different atmospheric analyses

    Directory of Open Access Journals (Sweden)

    A. Gobiet

    2007-02-01

    Full Text Available This study describes and evaluates a Global Navigation Satellite System (GNSS radio occultation (RO retrieval scheme particularly aimed at delivering bias-free atmospheric parameters for climate monitoring and research. The focus of the retrieval is on the sensible use of a priori information for careful high-altitude initialisation in order to maximise the usable altitude range. The RO retrieval scheme has been meanwhile applied to more than five years of data (September 2001 to November 2006 from the German CHAllenging Minisatellite Payload for geoscientific research (CHAMP satellite. In this study it was validated against various correlative datasets including the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS and the Global Ozone Monitoring for Occultation of Stars (GOMOS sensors on Envisat, five different atmospheric analyses, and the operational CHAMP retrieval product from GeoForschungsZentrum (GFZ Potsdam. In the global mean within 10 to 30 km altitude we find that the present validation observationally constrains the potential RO temperature bias to be <0.2 K. Latitudinally resolved analyses show biases to be observationally constrained to <0.2–0.5 K up to 35 km in most cases, and up to 30 km in any case, even if severely biased (about 10 K or more a priori information is used in the high altitude initialisation of the retrieval. No evidence is found for the 10–35 km altitude range of RO bias sources other than those potentially propagated downward from initialisation, indicating that the widely quoted RO promise of "unbiasedness and long-term stability due to intrinsic self-calibration" can indeed be realized given care in the data processing to strictly limit structural uncertainty. The results demonstrate that an adequate high-altitude initialisation technique is crucial for accurate stratospheric RO retrievals and that still common methods of initialising the involved hydrostatic integral with an upper boundary

  7. The influence of persistence of atmospheric circulation on temperature anomalies revisited

    Science.gov (United States)

    Cahynova, Monika; Huth, Radan

    2010-05-01

    In this study we focus on the effect of persistence of circulation types on the occurrence of high and low temperatures in summer and winter, respectively, at several stations in Central Europe in the second half of the 20th century. The key question is to compare the subjective Hess-Brezowsky catalogue with its "objectivized" version, because serious concern has arisen on the credibility of the mid-1980s enhancement of persistence of the Hess-Brezowsky circulation types. For a direct comparison we have chosen an objective (automated) circulation catalogue that is based on the definition of Hess-Brezowsky types, and that also reproduces the minimum 3-day duration of circulation types. In this catalogue there is no significant upward trend in the persistence of types. We identify "hot" and "cold" circulation types and examine if there is a trend within these types, either in their frequency or temperature severity. We then determine whether the persistence of circulation types plays a role in these trends, e.g. whether the warming of "hot" types is caused rather by their longer duration or by the overall rise of their extremeness. The research is conducted within the COST733 Action "Harmonisation and Applications of Weather Types Classifications for European Regions". The Czech participation in it is supported by the Ministry of Education, Youth, and Sports of the Czech Republic, contract OC115.

  8. Can climate sensitivity be estimated from short-term relationships of top-of-atmosphere net radiation and surface temperature?

    International Nuclear Information System (INIS)

    Increasing the knowledge in climate radiative feedbacks is critical for current climate studies. This work focuses on short-term relationships between global mean surface temperature and top-of-atmosphere (TOA) net radiation. The relationships may be used to characterize the climate feedback as suggested by some recent studies. As those recent studies, an energy balance model with ocean mixed layer and both radiative and non-radiative heat sources is used here. The significant improvement of current model is that climate system memories are considered. Based on model simulations, short-term relationship between global mean surface temperature and TOA net radiation (or the linear striation feature as suggested by previous studies) might represent climate feedbacks when the system had no memories. However, climate systems with the same short-term feedbacks but different memories would have a similar linear striation feature. This linear striation feature reflects only fast components of climate feedbacks and may not represent the total climate feedback even when the memory length of climate systems is minimal. The potential errors in the use of short-term relationships in estimations of climate sensitivity could be big. In short time scales, fast climate processes may overwhelm long-term climate feedbacks. Thus, the climate radiative feedback parameter obtained from short-term data may not provide a reliable estimate of climate sensitivity. This result also suggests that long-term observations of global surface temperature and TOA radiation are critical in the understanding of climate feedbacks and sensitivities.

  9. Hyperbaric storage of melon juice at and above room temperature and comparison with storage at atmospheric pressure and refrigeration.

    Science.gov (United States)

    Queirós, Rui P; Santos, Mauro D; Fidalgo, Liliana G; Mota, Maria J; Lopes, Rita P; Inácio, Rita S; Delgadillo, Ivonne; Saraiva, Jorge A

    2014-03-15

    Hyperbaric storage (8h) of melon juice (a highly perishable food) at 25, 30 and 37°C, under pressure at 25-150 MPa was compared with atmospheric pressure storage (0.1 MPa) at the same temperatures and under refrigeration (4°C). Comparatively to the refrigerated condition, hyperbaric storage at 50/75 MPa resulted in similar or lower microbial counts (total aerobic mesophiles, enterobacteriaceae, and yeasts/moulds) while at 100/150 MPa, the counts were lower for all the tested temperatures, indicating in the latter case, in addition to microbial growth inhibition, a microbial inactivation effect. At 25 MPa no microbial inhibition was observed. Physicochemical parameters of all samples stored under pressure (pH, titratable acidity, total soluble solids, browning degree and cloudiness) did not show a clear variation trend with pressure, being the results globally similar to refrigeration storage. These results show the potential of hyperbaric storage, at and above room temperature and with potential energy savings, comparatively to refrigeration.

  10. Dependence of Ozone Generation on Gas Temperature Distribution in AC Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

    Science.gov (United States)

    Takahashi, Go; Akashi, Haruaki

    AC atmospheric pressure multi-filament dielectric barrier discharge in oxygen has been simulated using two dimensional fluid model. In the discharge, three kinds of streamers have been obtained. They are primary streamers, small scale streamers and secondary streamers. The primary streamers are main streamers in the discharge and the small scale streamers are formed after the ceasing of the primary streamers. And the secondary streamers are formed on the trace of the primary streamers. In these streamers, the primary and the small scale streamers are very effective to generate O(3P) oxygen atoms which are precursor of ozone. And the ozone is generated mainly in the vicinity of the dielectrics. In high gas temperature region, ozone generation decreases in general. However, increase of the O(3P) oxygen atom density in high gas temperature region compensates decrease of ozone generation rate coefficient. As a result, amount of ozone generation has not changed. But if the effect of gas temperature was neglected, amount of ozone generation increases 10%.

  11. Temperature and atmospheric CO2 concentration estimates through the PETM using triple oxygen isotope analysis of mammalian bioapatite

    Science.gov (United States)

    Gehler, Alexander; Gingerich, Philip D.; Pack, Andreas

    2016-07-01

    The Paleocene–Eocene Thermal Maximum (PETM) is a remarkable climatic and environmental event that occurred 56 Ma ago and has importance for understanding possible future climate change. The Paleocene–Eocene transition is marked by a rapid temperature rise contemporaneous with a large negative carbon isotope excursion (CIE). Both the temperature and the isotopic excursion are well-documented by terrestrial and marine proxies. The CIE was the result of a massive release of carbon into the atmosphere. However, the carbon source and quantities of CO2 and CH4 greenhouse gases that contributed to global warming are poorly constrained and highly debated. Here we combine an established oxygen isotope paleothermometer with a newly developed triple oxygen isotope paleo-CO2 barometer. We attempt to quantify the source of greenhouse gases released during the Paleocene–Eocene transition by analyzing bioapatite of terrestrial mammals. Our results are consistent with previous estimates of PETM temperature change and suggest that not only CO2 but also massive release of seabed methane was the driver for CIE and PETM.

  12. Temperature and atmospheric CO2 concentration estimates through the PETM using triple oxygen isotope analysis of mammalian bioapatite.

    Science.gov (United States)

    Gehler, Alexander; Gingerich, Philip D; Pack, Andreas

    2016-07-12

    The Paleocene-Eocene Thermal Maximum (PETM) is a remarkable climatic and environmental event that occurred 56 Ma ago and has importance for understanding possible future climate change. The Paleocene-Eocene transition is marked by a rapid temperature rise contemporaneous with a large negative carbon isotope excursion (CIE). Both the temperature and the isotopic excursion are well-documented by terrestrial and marine proxies. The CIE was the result of a massive release of carbon into the atmosphere. However, the carbon source and quantities of CO2 and CH4 greenhouse gases that contributed to global warming are poorly constrained and highly debated. Here we combine an established oxygen isotope paleothermometer with a newly developed triple oxygen isotope paleo-CO2 barometer. We attempt to quantify the source of greenhouse gases released during the Paleocene-Eocene transition by analyzing bioapatite of terrestrial mammals. Our results are consistent with previous estimates of PETM temperature change and suggest that not only CO2 but also massive release of seabed methane was the driver for CIE and PETM. PMID:27354522

  13. Percentage Contributions from Atmospheric and Surface Features to Computed Brightness Temperatures

    Science.gov (United States)

    Jackson, G. S.

    2006-12-01

    Over the past few years, there has become an increasing interest in the use of millimeter-wave (mm-wave) and sub-millimeter-wave (submm-wave) radiometer observations to investigate the properties of ice particles in clouds. Passive radiometric channels respond to both the integrated particle mass throughout the volume and field of view, and to the amount, location, and size distribution of the frozen (and liquid) particles with the sensitivity varying for different frequencies and hydrometeor types. One methodology used since the 1960's to discern the relationship between the physical state observed and the brightness temperature (TB) is through the temperature weighting function profile. In this research, the temperature weighting function concept is exploited to analyze the sensitivity of various characteristics of the cloud profile, such as relative humidity, ice water path, liquid water path, and surface emissivity. In our numerical analysis, we compute the contribution (in Kelvin) from each of these cloud and surface characteristics, so that the sum of these various parts equals the computed TB. Furthermore, the percentage contribution from each of these characteristics is assessed. There is some intermingling/contamination of the contributions from various components due to the integrated nature of passive observations and the absorption and scattering between the vertical layers, but all in all the knowledge gained is useful. This investigation probes the sensitivity over several cloud classifications, such as cirrus, blizzards, light snow, anvil clouds, and heavy rain. The focus is on mm-wave and submm-wave frequencies, however discussions of the effects of cloud variations to frequencies as low as 10 GHz and up to 874 GHz will also be presented. The results show that nearly 60% of the TB value at 89 GHz comes from the earth's surface for even the heaviest blizzard snow rates. On the other hand, a significant percentage of the TB value comes from the snow

  14. Temperature and atmosphere tunability of the nanoplasmonic resonance of a volumetric eutectic-based Bi₂O₃-Ag metamaterial.

    Science.gov (United States)

    Sadecka, Katarzyna; Toudert, Johann; Surma, Hancza B; Pawlak, Dorota A

    2015-07-27

    Nanoplasmonic materials are intensively studied due to the advantages they bring in various applied fields such as photonics, optoelectronics, photovoltaics and medicine. However, their large-scale fabrication and tunability are still a challenge. One of the promising ways of combining these two is to use the self-organization mechanism and after-growth engineering as annealing for tuning the properties. This paper reports the development of a bulk nanoplasmonic, Bi2O3-Ag eutectic-based metamaterial with a tunable plasmonic resonance between orange and green wavelengths. The material, obtained by a simple growth technique, exhibits a silver nanoparticle-related localized surface plasmon resonance (LSPR) in the visible wavelength range. We demonstrate the tunability of the LSPR (spectral position, width and intensity) as a function of the annealing temperature, time and the atmosphere. The critical role of the annealing atmosphere is underlined, annealing in vacuum being the most effective option for a broad control of the LSPR. The various potential mechanisms responsible for tuning the localized surface plasmon resonance upon annealing are discussed in relation to the nanostructures of the obtained materials. PMID:26367573

  15. Degradation of Kresoxim-Methyl in Water: Impact of Varying pH, Temperature, Light and Atmospheric CO2 Level.

    Science.gov (United States)

    Khandelwal, Ashish; Gupta, Suman; Gajbhiye, Vijay T; Varghese, Eldho

    2016-01-01

    In the present investigation, persistence of kresoxim-methyl (a broad spectrum strobilurin fungicide) was studied in water. Results revealed that kresoxim-methyl readily form acid metabolite. Therefore, residues of kresoxim-methyl were quantified on the basis of parent molecule alone and sum total of kresoxim-methyl and its acid metabolite. In water, influence of various abiotic factors like pH, temperature, light and atmospheric carbon dioxide level on dissipation of kresoxim-methyl was studied. The half life value for kresoxim-methyl and total residue varied from 1 to 26.1 and 6.1 to 94.0 days under different conditions. Statistical analysis revealed the significant effect of abiotic factors on the dissipation of kresoxim-methyl from water.

  16. New Index for Winter Temperature of the Korean Peninsula and the East Asia based on the atmospheric teleconnection patterns

    Science.gov (United States)

    Kim, S. T.; Sohn, S. J.

    2015-12-01

    This study proposes a new index for monitoring and predicting winter temperature of the Korean Peninsula based on dominant atmospheric winter teleconnection modes and the utilization of the index is extended further to representing the East Asia Winter Monsoon (EAWM). Among the teleconnection modes it is found that both East Atlantic (EA) and Western Pacific (WP) modes are most strongly correlated with the Korean winter temperature in a way that the modes are partly associated with change in sea level pressure (SLP) around the Korean Peninsula. Particularly, the EA and WP modes are related with SLP variation over both Siberian High region and the Kuroshio extension region to the east of Japan, respectively. Based on this relationship, the two boxed regions representing the northeast-southwest SLP gradients are determined for the new index, which is found to be related with the EAWM circulation. The SLP gradients control the intensity of surface winds blowing into the Korean Peninsula from the Siberian regions which can transport cold air. The index shows the best performance in representing winter climate not only for the Korean Peninsula but also for the East Asia among the SLP-based EAWM indices. Furthermore, the new index maintains a better correlation with the winter temperature of both the East Asia and Korea over a certain period of years (i.e., running 30 year periods) than other SLP based EAWM indices and also shows good performance in delineating extreme cold/warm winters. The predictability of the new index and its usable potential for winter temperature prediction in coupled climate models are assessed and discussed further.

  17. Atmospheric corrosion effects of HNO 3—Influence of temperature and relative humidity on laboratory-exposed copper

    Science.gov (United States)

    Samie, Farid; Tidblad, Johan; Kucera, Vladimir; Leygraf, Christofer

    The effect of HNO 3 on the atmospheric corrosion of copper has been investigated at varied temperature (15-35 °C) and relative humidity (0-85% RH). Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) confirmed the existence of cuprite and gerhardtite as the two main corrosion products on the exposed copper surface. For determination of the corrosion rate and for estimation of the deposition velocity ( Vd) of HNO 3 on copper, gravimetry and ion chromatography has been employed. Temperature had a low effect on the corrosion of copper. A minor decrease in the mass gain was observed as the temperature was increased to 35 °C, possibly as an effect of lower amount of cuprite due to a thinner adlayer on the metal surface at 35 °C. The Vd of HNO 3 on copper, however, was unaffected by temperature. The corrosion rate and Vd of HNO 3 on copper was the lowest at 0% RH, i. e. dry condition, and increased considerably when changing to 40% RH. A maximum was reached at 65% RH and the mass gain remained constant when the RH was increased to 85% RH. The Vd of HNO 3 on copper at ⩾65% RH, 25 °C and 0.03 cm s -1 air velocity was as high as 0.15±0.03 cm s -1 to be compared with the value obtained for an ideal absorbent, 0.19±0.02 cm s -1. At sub-ppm levels of HNO 3, the corrosion rate of copper decreased after 14 d and the growth of the oxide levelled off after 7 d of exposure.

  18. The statistical inhomogeneity of surface air temperature in global atmospheric reanalyses

    Science.gov (United States)

    Ferguson, C. R.; Lee, M. H.

    2015-12-01

    Recently, a new generation of so-called climate reanalyses has emerged, including the 161-year NOAA—Cooperative Institute for Research in Environmental Sciences (NOAA-CIRES) Twentieth Century Reanalysis Version 2c (20CR V2c), the 111-year ECMWF pilot reanalysis of the twentieth century (ERA-20C), and the 55-year JMA conventional reanalysis (JRA-55C). These reanalyses were explicitly designed to achieve improved homogeneity through assimilation of a fixed subset of (mostly surface) observations. We apply structural breakpoint analysis to evaluate inhomogeneity of the surface air temperature in these reanalyses (1851-2011). For the modern satellite era (1979-2013), we intercompare their inhomogeneity to that of all eleven available satellite reanalyses. Where possible, we distinguish between breakpoints that are likely linked to climate variability and those that are likely due to an artificial observational network shift. ERA-20C is found to be the most homogenous reanalysis, with 40% fewer artificial breaks than 20CR V2c. Despite its gains in homogeneity, continued improvements to ERA-20C are needed. In this presentation, we highlight the most spatially extensive artificial break events in ERA-20C.

  19. Variable Temperature Setup for Scanning Electron Microscopy in Liquids and Atmospheric Pressure Gaseous Environments

    Science.gov (United States)

    Al-Asadi, Ahmed; Zhang, Jie; Li, Jianbo; Denault, Lauraine; Potyrailo, Radislav; Kolmakov, Andrei

    2014-03-01

    A thermoelectric cooling / heating setup for commercial Quantomix QX WETSEM scanning electron microscopy environmental cells was designed and tested. This addition allows extending ambient pressure in situ studies to be conducted in a wide temperature range both in liquid and gaseous environments. Instead of cooling/heating the entire body of QX-WETCELL, ultrathin polyimide electron transparent membrane window supported by metal mesh on the top of the cell has been used as an agent for heat transfer to/ from the Pelltier element. A butterfly wing of Morph sulkowskyi has been used as a model object in the QX-WETCELL's chamber due to its unique micro/nanostructure and peculiar wettability behavior. The dynamics of the water desorption, condensation and freezing processes were observed complementary using both optical microscopy and Scanning Electron Microscopy in vivo. The observations revel that the initial droplet formation were most likely taking place on the top of the wing ridges due to the waxy component of its surface. In addition, The SEM observation showed that the high intensity electron beam can heat the butterfly wing locally delaying the water condensation and freezing processes.

  20. Exploiting the atmosphere's memory for monthly, seasonal and interannual temperature forecasting using Scaling LInear Macroweather Model (SLIMM)

    Science.gov (United States)

    Del Rio Amador, Lenin; Lovejoy, Shaun

    2016-04-01

    Traditionally, most of the models for prediction of the atmosphere behavior in the macroweather and climate regimes follow a deterministic approach. However, modern ensemble forecasting systems using stochastic parameterizations are in fact deterministic/ stochastic hybrids that combine both elements to yield a statistical distribution of future atmospheric states. Nevertheless, the result is both highly complex (both numerically and theoretically) as well as being theoretically eclectic. In principle, it should be advantageous to exploit higher level turbulence type scaling laws. Concretely, in the case for the Global Circulation Models (GCM's), due to sensitive dependence on initial conditions, there is a deterministic predictability limit of the order of 10 days. When these models are coupled with ocean, cryosphere and other process models to make long range, climate forecasts, the high frequency "weather" is treated as a driving noise in the integration of the modelling equations. Following Hasselman, 1976, this has led to stochastic models that directly generate the noise, and model the low frequencies using systems of integer ordered linear ordinary differential equations, the most well-known are the Linear Inverse Models (LIM). For annual global scale forecasts, they are somewhat superior to the GCM's and have been presented as a benchmark for surface temperature forecasts with horizons up to decades. A key limitation for the LIM approach is that it assumes that the temperature has only short range (exponential) decorrelations. In contrast, an increasing body of evidence shows that - as with the models - the atmosphere respects a scale invariance symmetry leading to power laws with potentially enormous memories so that LIM greatly underestimates the memory of the system. In this talk we show that, due to the relatively low macroweather intermittency, the simplest scaling models - fractional Gaussian noise - can be used for making greatly improved forecasts

  1. Rlationship between the aerosol scattering ratio and temperature of atmosphere and the sensitivity of a Doppler wind lidar with iodine filter

    Institute of Scientific and Technical Information of China (English)

    Jinshan Zhu; Yubao Chen; Zhaoai Yan; Songhua Wu; Zhishen Liu

    2008-01-01

    The sensitivity of Doppler wind lidar is an important parameter which affects the performance of Doppler wind lidar. Aerosol scattering ratio, atmospheric temperature, and wind speed obviously affect the mea- surement of Doppler wind lidar with iodine filter. We discuss about the relationship between the measurement sensitivity and the above atmospheric parameters. The numerical relationship between them is given through the theoretical simulation and calculation.

  2. Seasonal modes of dryness and wetness variability over Europe and their connections with large scale atmospheric circulation and global sea surface temperature

    OpenAIRE

    Ionita, Monica; Boroneant, Constanta; Chelcea, Silvia

    2015-01-01

    The relationship between the seasonal modes of interannual variability of a multiscalar drought index over Europe and the large-scale atmospheric circulation and sea surface temperature (SST) anomaly fields is investigated through statistical analysis of observed and reanalysis data. It is shown that the seasonal modes of dryness and wetness variability over Europe and their relationship with the large-scale atmospheric circulation and global SST anomaly fields differ from one season to anoth...

  3. Polymer Surface Treatment by Atmospheric Pressure Low Temperature Surface Discharge Plasma:Its Characteristics and Comparison with Low Pressure Oxygen Plasma Treatment

    Institute of Scientific and Technical Information of China (English)

    Atsushi KUWABARA; Shin-ichi KURODA; Hitoshi KUBOTA

    2007-01-01

    The polymer treatment with a low-temperature plasma jet generated on the atmospheric pressure surface discharge (SD) plasma is performed.The change of the surface property over time,in comparison with low pressure oxygen (O2) plasma treatment,is examined.As one compares the treatment by atmospheric pressure plasma to that by the low pressure O2 plasma of PS (polystyrene) the treatment effects were almost in complete agreement.However,when the atmospheric pressure plasma was used for PP(polypropylene),it produced remarkable hydrophilic effects.

  4. Doppler Rayleigh/Mie/Raman lidar for wind and temperature measurements in the middle atmosphere up to 80 km

    Directory of Open Access Journals (Sweden)

    G. Baumgarten

    2010-11-01

    Full Text Available A direct detection Doppler lidar for measuring wind speed in the middle atmosphere up to 80 km with 2 h resolution was implemented in the ALOMAR Rayleigh/Mie/Raman lidar (69° N, 16° E. The random error of the line of sight wind is about 0.6 m/s and 10 m/s at 49 km and 80 km, respectively. We use a Doppler Rayleigh Iodine Spectrometer (DoRIS at the iodine line 1109 (~532.260 nm. DoRIS uses two branches of intensity cascaded channels to cover the dynamic range from 10 to 100 km altitude. The wind detection system was designed to extend the existing multi-wavelength observations of aerosol and temperature performed at wavelengths of 355 nm, 532 nm and 1064 nm. The lidar uses two lasers with a mean power of 14 W at 532 nm each and two 1.8 m diameter tiltable telescopes. Below about 49 km altitude the accuracy and time resolution is limited by the maximum count rate of the detectors used and not by the number of photons available. We report about the first simultaneous Rayleigh temperature and wind measurements by lidar in the strato- and mesosphere on 17 and 23 January 2009.

  5. Treatment of Candida albicans biofilms with low-temperature plasma induced by dielectric barrier discharge and atmospheric pressure plasma jet

    International Nuclear Information System (INIS)

    Because of some disadvantages of chemical disinfection in dental practice (especially denture cleaning), we investigated the effects of physical methods on Candida albicans biofilms. For this purpose, the antifungal efficacy of three different low-temperature plasma devices (an atmospheric pressure plasma jet and two different dielectric barrier discharges (DBDs)) on Candida albicans biofilms grown on titanium discs in vitro was investigated. As positive treatment controls, we used 0.1% chlorhexidine digluconate (CHX) and 0.6% sodium hypochlorite (NaOCl). The corresponding gas streams without plasma ignition served as negative treatment controls. The efficacy of the plasma treatment was determined evaluating the number of colony-forming units (CFU) recovered from titanium discs. The plasma treatment reduced the CFU significantly compared to chemical disinfectants. While 10 min CHX or NaOCl exposure led to a CFU log10 reduction factor of 1.5, the log10 reduction factor of DBD plasma was up to 5. In conclusion, the use of low-temperature plasma is a promising physical alternative to chemical antiseptics for dental practice.

  6. Temperature dependence of evaporation coeffcient of water in air and nitrogen under atmospheric pressure; study in water droplets

    CERN Document Server

    Zientara, M; Kolwas, K; Kolwas, M

    2008-01-01

    The evaporation coefficients of water in air and nitrogen were found as a function of temperature, by studying the evaporation of pure water droplet. The droplet was levitated in an electrodynamic trap placed in a climatic chamber maintaining atmospheric pressure. Droplet radius evolution and evaporation dynamics were studied with high precision by analyzing the angle-resolved light scattering Mie interference patterns. A model of quasi-stationary droplet evolution, accounting for the kinetic effects near the droplet surface was applied. In particular, the effect of thermal effusion (a short range analogue of thermal diffusion) was discussed and accounted for. The evaporation coefficient \\alpha in air and in nitrogen were found equal. \\alpha was found to decrease from ~ 0.18 to ~ 0.13 for the temperature range from 273.1 K to 293.1 K and follow the trend given by Arrhenius formula. The agreement with condensation coefficient values obtained with essentially different method by Li et al.[1] was found excellent...

  7. Treatment of Candida albicans biofilms with low-temperature plasma induced by dielectric barrier discharge and atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Koban, Ina; Welk, Alexander; Meisel, Peter; Holtfreter, Birte; Kocher, Thomas [Unit of Periodontology, Dental School, University of Greifswald, Rotgerberstr. 8, 17475 Greifswald (Germany); Matthes, Rutger; Huebner, Nils-Olaf; Kramer, Axel [Institute for Hygiene and Environmental Medicine, University of Greifswald, Walther-Rathenau-Str. 49 a, 17487 Greifswald (Germany); Sietmann, Rabea [Institute of Microbiology, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 15, 17487 Greifswald (Germany); Kindel, Eckhard; Weltmann, Klaus-Dieter, E-mail: ina.koban@uni-greifswald.d [Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

    2010-07-15

    Because of some disadvantages of chemical disinfection in dental practice (especially denture cleaning), we investigated the effects of physical methods on Candida albicans biofilms. For this purpose, the antifungal efficacy of three different low-temperature plasma devices (an atmospheric pressure plasma jet and two different dielectric barrier discharges (DBDs)) on Candida albicans biofilms grown on titanium discs in vitro was investigated. As positive treatment controls, we used 0.1% chlorhexidine digluconate (CHX) and 0.6% sodium hypochlorite (NaOCl). The corresponding gas streams without plasma ignition served as negative treatment controls. The efficacy of the plasma treatment was determined evaluating the number of colony-forming units (CFU) recovered from titanium discs. The plasma treatment reduced the CFU significantly compared to chemical disinfectants. While 10 min CHX or NaOCl exposure led to a CFU log{sub 10} reduction factor of 1.5, the log{sub 10} reduction factor of DBD plasma was up to 5. In conclusion, the use of low-temperature plasma is a promising physical alternative to chemical antiseptics for dental practice.

  8. Treatment of Candida albicans biofilms with low-temperature plasma induced by dielectric barrier discharge and atmospheric pressure plasma jet

    Science.gov (United States)

    Koban, Ina; Matthes, Rutger; Hübner, Nils-Olaf; Welk, Alexander; Meisel, Peter; Holtfreter, Birte; Sietmann, Rabea; Kindel, Eckhard; Weltmann, Klaus-Dieter; Kramer, Axel; Kocher, Thomas

    2010-07-01

    Because of some disadvantages of chemical disinfection in dental practice (especially denture cleaning), we investigated the effects of physical methods on Candida albicans biofilms. For this purpose, the antifungal efficacy of three different low-temperature plasma devices (an atmospheric pressure plasma jet and two different dielectric barrier discharges (DBDs)) on Candida albicans biofilms grown on titanium discs in vitro was investigated. As positive treatment controls, we used 0.1% chlorhexidine digluconate (CHX) and 0.6% sodium hypochlorite (NaOCl). The corresponding gas streams without plasma ignition served as negative treatment controls. The efficacy of the plasma treatment was determined evaluating the number of colony-forming units (CFU) recovered from titanium discs. The plasma treatment reduced the CFU significantly compared to chemical disinfectants. While 10 min CHX or NaOCl exposure led to a CFU log10 reduction factor of 1.5, the log10 reduction factor of DBD plasma was up to 5. In conclusion, the use of low-temperature plasma is a promising physical alternative to chemical antiseptics for dental practice.

  9. Real-time measurements of atmospheric CO using a continuous-wave room temperature quantum cascade laser based spectrometer.

    Science.gov (United States)

    Li, Jingsong; Parchatka, Uwe; Königstedt, Rainer; Fischer, Horst

    2012-03-26

    A compact, mobile mid-infrared laser spectrometer based on a thermoelectrically (TE) cooled continuous-wave room temperature quantum cascade laser and TE-cooled detectors has been newly developed to demonstrate the applicability of high sensitivity and high precision measurements of atmospheric CO. Performance of the instrument was examined with periodic measurements of reference sample and ambient air at 1 Hz sampling rate and a 1-hourly calibration cycle. The typical precision evaluated from replicate measurements of reference sample over the course of 66-h is 1.41 ppbv. With the utilization of wavelet filtering to improve the spectral SNR and minimize the dispersion of concentration values, a better precision of 0.88 ppbv and a lower detection limit of ~0.4 ppbv with sub-second averaging time have been achieved without reducing the fast temporal response. Allan variance analysis indicates a CO measurement precision of ~0.28 ppbv for optimal integration time of approximate 50 s. The absolute accuracy is limited by the calibration gas standard. This completely thermoelectrically cooled system shows the capability of long-term, unattended and continuous operation at room temperature without complicated cryogenic cooling. PMID:22453438

  10. Ice nucleation by surrogates for atmospheric mineral dust and mineral dust/sulfate particles at cirrus temperatures

    Directory of Open Access Journals (Sweden)

    C. M. Archuleta

    2005-01-01

    Full Text Available This study examines the potential role of some types of mineral dust and mineral dust with sulfuric acid coatings as heterogeneous ice nuclei at cirrus temperatures. Commercially-available nanoscale powder samples of aluminum oxide, alumina-silicate and iron oxide were used as surrogates for atmospheric mineral dust particles, with and without multilayer coverage of sulfuric acid. A sample of Asian dust aerosol particles was also studied. Measurements of ice nucleation were made using a continuous-flow ice-thermal diffusion chamber (CFDC operated to expose size-selected aerosol particles to temperatures between -45 and -60°C and a range of relative humidity above ice-saturated conditions. Pure metal oxide particles supported heterogeneous ice nucleation at lower relative humidities than those required to homogeneously freeze sulfuric acid solution particles at sizes larger than about 50 nm. The ice nucleation behavior of the same metal oxides coated with sulfuric acid indicate heterogeneous freezing at lower relative humidities than those calculated for homogeneous freezing of the diluted particle coatings. The effect of soluble coatings on the ice activation relative humidity varied with the respective uncoated core particle types, but for all types the heterogeneous freezing rates increased with particle size for the same thermodynamic conditions. For a selected size of 200 nm, the natural mineral dust particles were the most effective ice nuclei tested, supporting heterogeneous ice formation at an ice relative humidity of approximately 135%, irrespective of temperature. Modified homogeneous freezing parameterizations and theoretical formulations are shown to have application to the description of heterogeneous freezing of mineral dust-like particles with soluble coatings.

  11. Improving the low temperature dyeability of polyethylene terephthalate fabric with dispersive dyes by atmospheric pressure plasma discharge

    Science.gov (United States)

    Elabid, Amel E. A.; Zhang, Jie; Shi, Jianjun; Guo, Ying; Ding, Ke; Zhang, Jing

    2016-07-01

    Polyethylene terephthalate (PET) fiber and textile is one of the largest synthetic polymer commodity in the world. The great energy consumption and pollution caused by the high temperature and pressure dyeing of PET fibers and fabrics with disperse dyes has been caused concern these years. In this study, an atmospheric pressure plasma with fine and uniform filament discharge operated at 20 kHz has been used to improve the low temperature dyeability of PET fabric at 95 °C with three cation disperse dyes: Red 73, Blue 183 and Yellow 211. The dyes uptake percentage of the treated PET fabrics was observed to increase as twice as much of untreated fabric. The color strength rate was increased more than 20%. The reducing of the water contact angle and the raising of the capillary height of treated PET fabric strip indicate its hydrophilicity improvement. Scanning electron microscope (SEM) results display nano to micro size of etching pits appeared uniformly on the fiber surface of the treated PET. Simultaneously, X-ray photoelectron spectroscopy (XPS) analysis indicates an increase of the oxygen content in the surface caused by the introduction of polar groups such as Cdbnd O and COOH. The rough surface with improved polar oxygen groups showed hydrophilicity and affinity to C.I. dispersive dyes and is believed to be caused by the strong and very fine filament discharge appearing randomly at one place at an instant but evenly at many places at a longer period. This increases the diffusion and absorption of the C.I. disperse dyes on the PET fiber surface, which improve its low temperature dyeability.

  12. Atmospheric variables, nutrients, pH, salinity, and temperature collected by bottle and from meteorological stations in the Sea of Japan and the Yellow Sea from 01 July 1952 to 31 December 1998 (NODC Accession 0000032)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Atmospheric variables, nutrients, pH, salinity, and temperature data were collected using bottle casts in the Sea of Japan from 01 July 1952 to 31 December 1998....

  13. Stratospheric and mesospheric pressure-temperature profiles from rotational analysis of CO2 lines in atmospheric trace molecule spectroscopy/ATLAS 1 infrared solar occultation spectra

    Science.gov (United States)

    Stiller, G. P.; Gunson, M. R.; Lowes, L. L.; Abrams, M. C.; Raper, O. F.; Farmer, C. B.; Zander, R.; Rinsland, C. P.

    1995-01-01

    A simple, classical, and expedient method for the retrieval of atmospheric pressure-temperature profiles has been applied to the high-resolution infrared solar absorption spectra obtained with the atmospheric trace molecule spectroscopy (ATMOS) instrument. The basis for this method is a rotational analysis of retrieved apparent abundances from CO2 rovibrational absorption lines, employing existing constituent concentration retrieval software used in the analysis of data returned by ATMOS. Pressure-temperature profiles derived from spectra acquired during the ATLAS 1 space shuttle mission of March-April 1992 are quantitatively evaluated and compared with climatological and meteorological data as a means of assessing the validity of this approach.

  14. A statistical examination of Nimbus-7 SMMR data and remote sensing of sea surface temperature, liquid water content in the atmosphere and surface wind speed

    Science.gov (United States)

    Prabhakara, C.; Chang, A. T. C.; Gloersen, P.; Wang, I.

    1983-01-01

    Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) brightness temperature measurements over the global oceans have been examined with the help of statistical and empirical techniques. Such analyses show that zonal averages of brightness temperature measured by SMMR over the oceans on a large scale are primarily influenced by the water vapor in the atmosphere. Liquid water in the clouds and rain, which has a much smaller spatial and temporal scale, contributes substantially to the variability of the SMMR measurements within the latitudinal zones. The surface wind not only increases the surface emissivity, but through its interactions with the atmosphere produces correlations in the SMMR brightness temperature data that have significant meteorological implications. It is found that a simple meteorological model can explain the general characteristics of the SMMR data. With the help of this model, methods to infer over the global oceans, the surface temperature, liquid water content in the atmosphere, and surface wind speed are developed. Monthly mean estimates of the sea surface temperature and surface winds are compared with the ship measurements. Estimates of liquid water content in the atmosphere are consistent with earlier satellite measurements. Previously announced in STAR as N83-19187

  15. A statistical examination of Nimbus 7 SMMR data and remote sensing of sea surface temperature, liquid water content in the atmosphere and surfaces wind speed

    Science.gov (United States)

    Prabhakara, C.; Wang, I.; Chang, A. T. C.; Gloersen, P.

    1982-01-01

    Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) brightness temperature measurements over the global oceans have been examined with the help of statistical and empirical techniques. Such analyses show that zonal averages of brightness temperature measured by SMMR, over the oceans, on a large scale are primarily influenced by the water vapor in the atmosphere. Liquid water in the clouds and rain, which has a much smaller spatial and temporal scale, contributes substantially to the variability of the SMMR measurements within the latitudinal zones. The surface wind not only increases the surface emissivity but through its interactions with the atmosphere produces correlations, in the SMMR brightness temperature data, that have significant meteorological implications. It is found that a simple meteorological model can explain the general characteristics of the SMMR data. With the help of this model methods to infer over the global oceans, the surface temperature, liquid water content in the atmosphere, and surface wind speed are developed. Monthly mean estimates of the sea surface temperature and surface winds are compared with the ship measurements. Estimates of liquid water content in the atmosphere are consistent with earlier satellite measurements.

  16. Low temperature carrier transport study of monolayer MoS{sub 2} field effect transistors prepared by chemical vapor deposition under an atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinke, E-mail: xkliu@szu.edu.cn, E-mail: wujing026@gmail.com; He, Jiazhu; Tang, Dan; Lu, Youming; Zhu, Deliang; Liu, Wenjun; Cao, Peijiang; Han, Sun [College of Materials Science and Engineering, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Nanshan District Key Lab for Biopolymer and Safety Evaluation, Shenzhen University, 3688 Nanhai Ave, Shenzhen 518060 (China); Liu, Qiang; Wen, Jiao; Yu, Wenjie [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, CAS, 865 Chang Ning Road, Shanghai 200050 (China); Liu, Wenjun [State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, 220 Handan Road, Shanghai 200433 (China); Wu, Jing, E-mail: xkliu@szu.edu.cn, E-mail: wujing026@gmail.com [Department of Physics, National University of Singapore, 21 Lower Kent Ridge Road, 117576 Singapore (Singapore); He, Zhubing [Department of Materials Science and Engineering, South University of Science and Technology of China, 1088 Xueyuan Road, Shenzhen 518055 (China); Ang, Kah-Wee [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117583 Singapore (Singapore)

    2015-09-28

    Large size monolayer Molybdenum disulphide (MoS{sub 2}) was successfully grown by chemical vapor deposition method under an atmospheric pressure. The electrical transport properties of the fabricated back-gate monolayer MoS{sub 2} field effect transistors (FETs) were investigated under low temperatures; a peak field effect mobility of 59 cm{sup 2}V{sup −1}s{sup −1} was achieved. With the assist of Raman measurement under low temperature, this work identified the mobility limiting factor for the monolayer MoS{sub 2} FETs: homopolar phonon scattering under low temperature and electron-polar optical phonon scattering at room temperature.

  17. Low temperature carrier transport study of monolayer MoS2 field effect transistors prepared by chemical vapor deposition under an atmospheric pressure

    International Nuclear Information System (INIS)

    Large size monolayer Molybdenum disulphide (MoS2) was successfully grown by chemical vapor deposition method under an atmospheric pressure. The electrical transport properties of the fabricated back-gate monolayer MoS2 field effect transistors (FETs) were investigated under low temperatures; a peak field effect mobility of 59 cm2V−1s−1 was achieved. With the assist of Raman measurement under low temperature, this work identified the mobility limiting factor for the monolayer MoS2 FETs: homopolar phonon scattering under low temperature and electron-polar optical phonon scattering at room temperature

  18. Decadal variability of the Tropical Atlantic Ocean Surface Temperature in shipboard measurements and in a Global Ocean-Atmosphere model

    Science.gov (United States)

    Mehta, Vikram M.; Delworth, Thomas

    1995-01-01

    Sea surface temperature (SST) variability was investigated in a 200-yr integration of a global model of the coupled oceanic and atmospheric general circulations developed at the Geophysical Fluid Dynamics Laboratory (GFDL). The second 100 yr of SST in the coupled model's tropical Atlantic region were analyzed with a variety of techniques. Analyses of SST time series, averaged over approximately the same subregions as the Global Ocean Surface Temperature Atlas (GOSTA) time series, showed that the GFDL SST anomalies also undergo pronounced quasi-oscillatory decadal and multidecadal variability but at somewhat shorter timescales than the GOSTA SST anomalies. Further analyses of the horizontal structures of the decadal timescale variability in the GFDL coupled model showed the existence of two types of variability in general agreement with results of the GOSTA SST time series analyses. One type, characterized by timescales between 8 and 11 yr, has high spatial coherence within each hemisphere but not between the two hemispheres of the tropical Atlantic. A second type, characterized by timescales between 12 and 20 yr, has high spatial coherence between the two hemispheres. The second type of variability is considerably weaker than the first. As in the GOSTA time series, the multidecadal variability in the GFDL SST time series has approximately opposite phases between the tropical North and South Atlantic Oceans. Empirical orthogonal function analyses of the tropical Atlantic SST anomalies revealed a north-south bipolar pattern as the dominant pattern of decadal variability. It is suggested that the bipolar pattern can be interpreted as decadal variability of the interhemispheric gradient of SST anomalies. The decadal and multidecadal timescale variability of the tropical Atlantic SST, both in the actual and in the GFDL model, stands out significantly above the background 'red noise' and is coherent within each of the time series, suggesting that specific sets of

  19. The effect of test atmosphere on the formation and propagation of creep cracks in commercial high temperature alloys

    International Nuclear Information System (INIS)

    The influence of surface cracks caused by corrosion on the creep rupture properties of the alloys INCOLOY 800H and INCONEL 617 has been investigated for temperatures in the range 1073 K to 1223 K. The test environments were air and impure helium simulating the primary coolant gas of a high temperature reactor (HTR helium). The depths of surface cracks in creep test specimens were measured metallographically and a characteristic crack depth, a90, was derived. a90 is defined so that 90% of the cracks present have depths below a90. The dependence of a90 on test time, creep strain and stress was examined. The growth of creep cracks at the specimen surface as a function of the creep strain was described analytically. This allowed the stress increase due to loss of specimen cross section by surface crack formation to be estimated. It was shown that the surface cracks resulting from corrosion lead to an increase in the creep rate at creep strains above 5%, but the increases were similar in both atmospheres. Rupture of the specimens occurred when the surface cracks and voids developed inside the specimen due to the creep damage processes. This is the main reason for the similar creep rupture properties of the alloys in the two test environments. Finally, a method has been developed to allow the plotting of the depth of surface cracks caused by corrosion with the stress-rupture curves. In this type of diagram, the damage resulting from surface cracks can be related to the creep rupture data to indicate whether corrosion effects need to be considered in the derivation of design stresses. (orig./IHOE)

  20. Local flux-profile relationships of wind speed and temperature in a canopy layer in atmospheric stable conditions

    Science.gov (United States)

    Zhang, G.; Leclerc, M. Y.; Karipot, A.

    2010-11-01

    The particularities of the physics of the canopy layer pose challenges to the determination and use of traditional universal functions so helpful in the atmospheric surface layer. Progress toward "universal-like functions" such as those provided by Monin-Obukhov similarity theory for the canopy layer has been modest. One of the challenges lies in that the assumptions underlying Monin-Obukhov similarity theory do not hold within a canopy layer. This paper thus examines the local flux-profile relations for wind (Φm) and for temperature (Φh). It uses three different stability parameters, i.e., h/L(h) at tree top, local z/L(z), and the local bulk Richardson number (Ri), within a tall forest canopy in nighttime stable (indicated by h/L(h) > 0) conditions. Results suggest that the in-canopy Φm can be described using the local Richardson number Ri. Furthermore, Φm is found to increase linearly with Ri in the upper canopy layer for |Ri| 1, |Φm| decreases with |Ri| in a power function, a result consistent for all levels of measurements within the canopy. When both local Φh and local Ri are positive, i.e., the local downward turbulent heat flux is consistent with the local temperature gradient, the local Φh increases with the local Ri when Ri 1. The relationship between local Φh and Ri disappears when counter-gradient heat transfer occurs in strongly stable conditions. A self-correlation analysis is used to examine the influence of self-correlation and the physical meaning of these relationships.

  1. Proliferation assay of mouse embryonic stem (ES) cells exposed to atmospheric-pressure plasmas at room temperature

    International Nuclear Information System (INIS)

    Proliferation assays of mouse embryonic stem (ES) cells have been performed with cell culture media exposed to atmospheric-pressure plasmas (APPs), which generate reactive species in the media at room temperature. It is found that serum in cell culture media functions as a scavenger of highly reactive species and tends to protect cells in the media against cellular damage. On the other hand, if serum is not present in a cell culture medium when it is exposed to APP, the medium becomes cytotoxic and cannot be detoxified by serum added afterwards. Plasma-induced cytotoxic media hinder proliferation of mouse ES cells and may even cause cell death. It is also shown by nuclear magnetic resonance spectroscopy that organic compounds in cell culture media are in general not significantly modified by plasma exposure. These results indicate that if there is no serum in media when they are exposed to APPs, highly reactive species (such as OH radicals) generated in the media by the APP exposure are immediately converted to less reactive species (such as H2O2), which can no longer readily react with serum that is added to the medium after plasma exposure. This study has clearly shown that it is these less reactive species, rather than highly reactive species, that make the medium cytotoxic to mouse ES cells. (paper)

  2. Mutation Breeding of Extracellular Polysaccharide-Producing Microalga Crypthecodinium cohnii by a Novel Mutagenesis with Atmospheric and Room Temperature Plasma

    Directory of Open Access Journals (Sweden)

    Bin Liu

    2015-04-01

    Full Text Available Extracellular polysaccharides (EPS produced by marine microalgae have the potential to be used as antioxidants, antiviral agents, immunomodulators, and anti-inflammatory agents. Although the marine microalga Crypthecodinium cohnii releases EPS during the process of docosahexaenoic acid (DHA production, the yield of EPS remains relatively low. To improve the EPS production, a novel mutagenesis of C. cohnii was conducted by atmospheric and room temperature plasma (ARTP. Of the 12 mutants obtained, 10 mutants exhibited significantly enhanced EPS yield on biomass as compared with the wild type strain. Among them, mutant M7 was the best as it could produce an EPS volumetric yield of 1.02 g/L, EPS yield on biomass of 0.39 g/g and EPS yield on glucose of 94 mg/g, which were 33.85%, 85.35% and 57.17% higher than that of the wild type strain, respectively. Results of the present study indicated that mutagenesis of the marine microalga C. cohnii by ARTP was highly effective leading to the high-yield production of EPS.

  3. Breeding L-arginine-producing strains by a novel mutagenesis method: Atmospheric and room temperature plasma (ARTP).

    Science.gov (United States)

    Cheng, Gong; Xu, Jianzhong; Xia, Xiuhua; Guo, Yanfeng; Xu, Kai; Su, Cunsheng; Zhang, Weiguo

    2016-07-01

    A plasma jet, driven by an active helium atom supplied with an atmospheric and room temperature plasma (ARTP) biological breeding system, was used as a novel method to breed L-arginine high-yielding strains. A mutant with resistance to L-homoarginine and 8-azaguaine, ARG 3-15 (L-HA(r), 8-AG(r), L-His(-)), was screened after several rounds of screening. The L-arginine production of these mutants was more than that of the original strain, increased by 43.79% for ARG 3-15. Moreover, N-acetyl-L-glutamate synthase activity of these mutants was also increased. After a series of passages, the hereditary properties of these mutants were found to be stable. Interestingly, beet molasses was utilized in a co-feeding fermentation and benefited to increase the productivity by 5.88%. Moreover, the fermentation with 1.0 g/L betaine could produce 9.33% more L-arginine than without betaine. In fed-batch fermentation, C. glutamicum ARG 3-15 began to produce L-arginine at the initial of logarithmic phase, and continuously increased over 24 hr to a final titer of 45.36 ± 0.42 g/L. The L-arginine productivity was 0.571 g/L/hr and the conversion of glucose (α) was 32.4% after 96 hr. These results indicated that C. glutamicum ARG 3-15 is a promising industrial producer.

  4. Two fast temperature sensors for probing of the atmospheric boundary layer using small remotely piloted aircraft (RPA

    Directory of Open Access Journals (Sweden)

    N. Wildmann

    2013-08-01

    Full Text Available Two types of temperature sensors are designed and tested: a thermocouple and a fine wire resistance thermometer. The intention of this study is to figure out which kind of measurement principle is in general more suited for atmospheric boundary layer meteorology with small remotely piloted aircraft (RPA. The sensors are calibrated in a NIST traceable climate chamber and validated in flight against tower measurements, radiosondes and remote sensing. The sensors have a measurement range of at least −10–50 °C, an absolute RMS error of less than ±0.2 K which is stable over the lifetime of the sensors, and a resolution of about 0.01 K. Both devices are tested for typical errors like radiation error and adiabatic heating, as well as for their dynamic response. Spectral resolutions of up to approximately 10 Hz can be obtained with both sensors, which makes them suitable for turbulence measurement. Their low cost of less than 100 EUR in pure hardware is a major advantage for research with small RPA.

  5. Silver nanoparticles sintering at low temperature on a copper substrate: In situ characterization under inert atmosphere and air

    Directory of Open Access Journals (Sweden)

    Sopousek J.

    2012-01-01

    Full Text Available Silver nanoparticles (Ag-NPs were prepared by wet synthesis. The Ag-NPs suspension and the copper substrate plate were used for a preparation of substrate-nanoparticle-substrate samples. The sandwich like samples Cu/Ag/Cu were prepared and investigated in-situ at the isothermal external conditions (IEC and inside apparatus for simultaneous thermal analysis STA409 (DSC. The in-situ results of the electrical resistance were recorded during the Cu/Ag/Cu (IEC sample preparation and heat treatment. Thermal effects of the Ag-NPs sintering between copper substrates were measured by differential scanning calorimetry (DSC under different atmospheres. The prepared Cu/Ag/Cu sandwich samples were characterised by means of both optical and electron microscopy. The process of the low temperature sintering inside calorimeter of the Ag-NPs was monitored using both thermogravimetry (TG and DSC technique under inert gas and under synthetic air. The exothermic heat effect of nanosilver sintering was evaluated.

  6. Three different low-temperature plasma-based methods for hydrophilicity improvement of polyethylene films at atmospheric pressure

    International Nuclear Information System (INIS)

    Three different low-temperature plasma-based methods were used to improve the surface hydrophilicity of polyethylene (PE) films, and all the modification processes were carried out by employing an atmospheric pressure plasma jet (APPJ) system. (a) PE films were directly modified by APPJ using a gas mixture of He and O2. (b) Acrylic acid (AA) was introduced into the system and a polymer acrylic acid (PAA) coating was deposited onto the PE films. (c) AA was grafted onto the PE surface activated by plasma pre-treatment. It was found that the hydrophilicity of the PE films was significantly improved for all the three methods. However, the samples modified by Process (a) showed hydrophobicity recovery after a storage time of 20 days while no significant change was found in samples modified by Process (b) and Process (c). The Fourier transform infrared spectroscopy (FTIR) results indicated that the most intensive C=O peak was detected on the PE surface modified by Process (c). According to the X-ray photoelectron spectroscopy (XPS) analysis, the ratios of oxygen-containing polar groups for samples modified by Process (b) and Process (c) were higher than that modified by Process (a)

  7. Effect of irradiation and modified atmosphere packaging on the microbiological safety of minced pork stored under temperature abuse conditions

    International Nuclear Information System (INIS)

    The safety of irradiated pork packed in 25% CO2:75% N2 and stored at abuse temperature (10 or 15°C) was assessed by inoculation studies involving Salmonella typhimurium, Listeria monocytogenes, Escherichia coli, Yersinia enterocolitica and Clostridium perfringens. Irradiation to a dose of 1.75 kGy reduced pathogen numbers to below the detection limit of 102 cells g-1. When higher inoculum levels were used (106 cells g-1) irradiation at 1.75 kGy reduced pathogen numbers by 1 –>5 log10 cycles depending on strain. Clostridium perfringens was the most resistant, and Y. enterocolitica the most sensitive of the pathogens studied. In all cases when high numbers (106 to 107g-1) of spoilage and/or pathogenic bacteria were present initially on the pork the meat appeared spoiled, and although irradiation reduced the number of microorganisms, the meat was still unacceptable from a sensory viewpoint after treatment. It was concluded that the microbiological safety of irradiated, modified atmosphere packaged (MAP) pork is better than that of unirradiated MAP pork

  8. Exoplanet Atmospheres

    CERN Document Server

    Seager, S

    2010-01-01

    At the dawn of the first discovery of exoplanets orbiting sun-like stars in the mid-1990s, few believed that observations of exoplanet atmospheres would ever be possible. After the 2002 Hubble Space Telescope detection of a transiting exoplanet atmosphere, many skeptics discounted it as a one-object, one-method success. Nevertheless, the field is now firmly established, with over two dozen exoplanet atmospheres observed today. Hot Jupiters are the type of exoplanet currently most amenable to study. Highlights include: detection of molecular spectral features; observation of day-night temperature gradients; and constraints on vertical atmospheric structure. Atmospheres of giant planets far from their host stars are also being studied with direct imaging. The ultimate exoplanet goal is to answer the enigmatic and ancient question, "Are we alone?" via detection of atmospheric biosignatures. Two exciting prospects are the immediate focus on transiting super Earths orbiting in the habitable zone of M-dwarfs, and u...

  9. Gas chromatography interfaced with atmospheric pressure ionization-quadrupole time-of-flight-mass spectrometry by low-temperature plasma ionization

    DEFF Research Database (Denmark)

    Norgaard, Asger W.; Kofoed-Sorensen, Vivi; Svensmark, Bo;

    2013-01-01

    A low temperature plasma (LTP) ionization interface between a gas chromatograph (GC) and an atmospheric pressure inlet mass spectrometer, was constructed. This enabled time-of-flight mass spectrometric detection of GC-eluting compounds. The performance of the setup was evaluated by injection...

  10. Validation of HITEMP-2010 for carbon dioxide and water vapour at high temperatures and atmospheric pressures in 450-7600cm-1 spectral range

    DEFF Research Database (Denmark)

    Alberti, Michael; Weber, Roman; Mancini, Marco;

    2015-01-01

    The objective of the work is validation of HITEMP-2010 at atmospheric pressures and temperatures reaching 1770K. To this end, spectral transmissivities at 1cm-1 resolution and excellent signal-to-noise-ratio have been measured for 22 CO2/H2O/N2 mixtures. In this paper we consider the 450cm-1-7600cm...

  11. Modeling the impact of vapor thymol concentration, temperature and modified atmosphere condition on growth behavior of Salmonella spp. on raw shrimp

    Science.gov (United States)

    Salmonella spp. is a microorganism of concern, on a global basis, for raw shrimp. This research modeled the impact of vapor thymol concentration (0, 0.8 and 1.6 mg/l), storage temperature (8, 12 and 16 degree C) and modified atmosphere packaging (0.04 and 59.5 percent CO2) against the growth behavio...

  12. Remote measurement of atmospheric temperature profiles in clouds with rotational Raman lidar; Fernmessung atmosphaerischer Temperaturprofile in Wolken mit Rotations-Raman-Lidar

    Energy Technology Data Exchange (ETDEWEB)

    Behrendt, A. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Physikalische und Chemische Analytik

    2000-07-01

    The development of a lidar receiver for remote measurements of atmospheric temperature profiles with the rotational Raman method is described. By a new receiver concept, this instrument allowed for the first time remote temperature measurements without any perturbation by the presence of clouds up to a backscatter ratio of 45. In addition, high efficiency of the spectral separation of atmospheric backscatter signals leads to improved measurement resolution: the minimum integration time needed for a statistical uncertainty < {+-}1 K at, e.g., 10 km height and 960 m height resolution is only 5 minutes. The measurement range extends to over 45 km altitude. Results of field campaigns obtained with the instrument are presented and discussed. In winter 1997/98, the instrument was transferred with the GKSS Raman lidar to Esrange (67.9 N, 21.1 E) in northern Sweden, where pioneering remote measurements of local temperatures in orographically induced polar stratospheric clouds could be carried out. (orig.)

  13. GHRSST Level 2P Global skin Sea Surface Temperature from the Infrared Atmospheric Sounding Interferometer (IASI) on the Metop-B satellite (GDS V2) produced by OSI SAF (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 2P dataset based on multi-channel sea surface temperature (SST) retrievals generated in real-time...

  14. GHRSST Level 2P Global skin Sea Surface Temperature from the Infrared Atmospheric Sounding Interferometer (IASI) on the Metop-A satellite (GDS V2) produced by OSI SAF (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A global 1 km Group for High Resolution Sea Surface Temperature (GHRSST) Level 2P dataset based on multi-channel sea surface temperature (SST) retrievals generated...

  15. Local flux-profile relationships of wind speed and temperature in a canopy layer in atmospheric stable conditions

    Directory of Open Access Journals (Sweden)

    G. Zhang

    2010-06-01

    Full Text Available The particularities of the physics of the canopy layer pose challenges to the determination and use of traditional universal functions so helpful in the atmospheric surface layer. Progress toward "universal-like functions" such as those provided by Monin-Obukhov similarity theory for the canopy layer has been modest. One of the challenges lies in that the assumptions underlying Monin-Obukhov similarity theory do not hold within a canopy layer. This paper thus examines the local flux-profile relations for wind (φm and for temperatureh using three different stability parameters, i.e., h/L(h at tree top, local z/L(z, and local bulk Richardson number (Ri, within a tall forest canopy in nighttime stable (indicated by h/L(h>0 conditions. Results suggest that the in-canopy φm can be described using the local Richardson number Ri. φm is found to increase linearly with Ri in the upper canopy layer for |Ri|<1. When local |Ri|>1, |φm| decreases with |Ri|, a result consistent for all levels of measurements within the canopy. When both local φh and local Ri are positive, i.e., local downward turbulent heat flux is consistent with local temperature gradient, local φh increases with local Ri when Ri<1 but does not change with Ri (or much more scattered when Ri>1. The relationship between local φh and Ri disappears when counter-gradient heat transfer occurs in strongly stable conditions. A self-correlation analysis is used to examine the influence of self-correlation and the physical meaning of these relationships.

  16. Local flux-profile relationships of wind speed and temperature in a canopy layer in atmospheric stable conditions

    Directory of Open Access Journals (Sweden)

    G. Zhang

    2010-11-01

    Full Text Available The particularities of the physics of the canopy layer pose challenges to the determination and use of traditional universal functions so helpful in the atmospheric surface layer. Progress toward "universal-like functions" such as those provided by Monin-Obukhov similarity theory for the canopy layer has been modest. One of the challenges lies in that the assumptions underlying Monin-Obukhov similarity theory do not hold within a canopy layer. This paper thus examines the local flux-profile relations for wind (Φm and for temperature (Φh. It uses three different stability parameters, i.e., h/L(h at tree top, local z/L(z, and the local bulk Richardson number (Ri, within a tall forest canopy in nighttime stable (indicated by h/L(h > 0 conditions. Results suggest that the in-canopy Φm can be described using the local Richardson number Ri. Furthermore, Φm is found to increase linearly with Ri in the upper canopy layer for |Ri| < 1. When local |Ri| > 1, |Φm| decreases with |Ri| in a power function, a result consistent for all levels of measurements within the canopy. When both local Φh and local Ri are positive, i.e., the local downward turbulent heat flux is consistent with the local temperature gradient, the local Φh increases with the local Ri when Ri < 1. However, Φh does not change with Ri (or much more scattered when Ri > 1. The relationship between local Φh and Ri disappears when counter-gradient heat transfer occurs in strongly stable conditions. A self-correlation analysis is used to examine the influence of self-correlation and the physical meaning of these relationships.

  17. Trapping of water vapor from an atmosphere by condensed silicate matter formed by high-temperature pulse vaporization

    Science.gov (United States)

    Gerasimov, M. V.; Dikov, Yu. P.; Yakovlev, O. I.; Wlotzka, F.

    1993-01-01

    The origin of planetary atmospheres is thought to be the result of bombardment of a growing planet by massive planetesimals. According to some models, the accumulation of released water vapor and/or carbon dioxide can result in the formation of a dense and hot primordial atmosphere. Among source and sink processes of atmospheric water vapor the formation of hydroxides was considered mainly as rehydration of dehydrated minerals (foresterite and enstatite). From our point of view, the formation of hydroxides is not limited to rehydration. Condensation of small silicate particles in a spreading vapor cloud and their interaction with a wet atmosphere can also result in the origin of hydrated phases which have no genetic connections with initial water bearing minerals. We present results of two experiments of a simulated interaction of condensed silicate matter which originated during vaporization of dry clinopyroxene in a wet helium atmosphere.

  18. Atmospheric temperature profiling in the presence of clouds with a pure rotational Raman lidar by use of an interference-filter-based polychromator.

    Science.gov (United States)

    Behrendt, A; Reichardt, J

    2000-03-20

    A lidar polychromator design for the measurement of atmospheric temperature profiles in the presence of clouds with the rotational Raman method is presented. The design utilizes multicavity interference filters mounted sequentially at small angles of incidence. Characteristics of this design are high signal efficiency and adjustable center wavelengths of the filters combined with a stable and relatively simple experimental setup. High suppression of the elastic backscatter signal in the rotational Raman detection channels allows temperature measurements independent of the presence of thin clouds or aerosol layers; no influence of particle scattering on the lidar temperature profile was observed in clouds with a backscatter ratio of at least 45. The minimum integration time needed for temperature profiling with a statistical temperature error of +/-1 K at, e.g., 20-km height and 960-m height resolution is 1.5 h.

  19. An All-Solid-State, Room-Temperature, Heterodyne Receiver for Atmospheric Spectroscopy at 1.2 THz

    Science.gov (United States)

    Siles, Jose V.; Mehdi, Imran; Schlecht, Erich T.; Gulkis, Samuel; Chattopadhyay, Goutam; Lin, Robert H.; Lee, Choonsup; Gill, John J.; Thomas, Bertrand; Maestrini, Alain E.

    2013-01-01

    been specifically optimized to maximize the mixer performance beyond 1 THz. The measured DSB noise temperatures and conversion losses of the receiver are 2,000 to 3,500 K and 12 to 14 dB, respectively, at 120 K, and 4,000 to 6,000 K and 13 to 15 dB, respectively, at 300 K. These results establish the state-of-the-art for all-solid-state, all-planar heterodyne receivers at 1.2 THz operating at either room temperature or using passive cooling only. Since no cryogenic cooling is needed, the receiver is eminently suited to atmospheric heterodyne spectroscopy of the outer planets and their moons.

  20. CORRELATION BETWEEN THE 22-YEAR SOLAR MAGNETIC CYCLE AND THE 22-YEAR QUASICYCLE IN THE EARTH'S ATMOSPHERIC TEMPERATURE

    Energy Technology Data Exchange (ETDEWEB)

    Qu Weizheng; Zhao Jinping; Huang Fei; Deng Shenggui, E-mail: quweizhe@ouc.edu.cn [College of Environment Oceanography, Ocean University of China, Qingdao 266100 (China)

    2012-07-15

    According to the variation pattern of the solar magnetic field polarity and its relation to the relative sunspot number, we established the time series of the sunspot magnetic field polarity index and analyzed the strength and polarity cycle characteristics of the solar magnetic field. The analysis showed the existence of a cycle with about a 22-year periodicity in the strength and polarity of the solar magnetic field, which proved the Hale proposition that the 11-year sunspot cycle is one-half of the 22-year solar magnetic cycle. By analyzing the atmospheric temperature field, we found that the troposphere and the stratosphere in the middle latitude of both the northern and southern hemispheres exhibited a common 22-year quasicycle in the atmospheric temperature, which is believed to be attributable to the 22-year solar magnetic cycle.

  1. Production of a two-years meteorological dataset with a coupling framework between a Limited Area Atmospheric Model and a sequential Land Surface Temperature Assimilation scheme

    Science.gov (United States)

    Campo, Lorenzo; Castelli, Fabio; Entekhabi, Dara; Caparrini, Francesca

    2010-05-01

    The representation of the surface phenomena like the turbulent exchange of heat between the land and the atmosphere is a traditional weakness in the atmospheric models. These phenomena have been often neglected or poorly represented in the past, especially in the Global Circulation Models. The modern generation models (in particular Limited Area Models) present, on the opposite, much more accurate modelizations that require very complex parametrization, difficult or impossible to retrieve with sufficient accuracy. In this work remote sensed maps of Land Surface Temperature retrieved by MSG-SEVIRI sensor have been used in a 1D variational assimilation scheme in order to produce optimal estimates of the surface energy budget in terms of sensible and latent heat fluxes patterns. This assimilation scheme, ACHAB, has then been coupled with the limited area atmospheric model RAMS replacing the surface module of the latter, LEAF-3, with the assimilation run products. A two years long meteorological dataset (March 1st, 2005 - December 31st, 2006) was produced on the Italian territory using this coupling framework. A control run was used in order to evaluate performances of the atmospheric model also in absence of the LST assimilation. Evaluations of the results of the coupling framework by comparison with both observations of the ground sensors network and the atmospheric soundings available in the study period are presented.

  2. Use of Total Precipitable Water Classification of A Priori Error and Quality Control in Atmospheric Temperature and Water Vapor Sounding Retrieval

    Institute of Scientific and Technical Information of China (English)

    Eun-Han KWON; Jun LI; Jinlong LI; B. J. SOHN; Elisabeth WEISZ

    2012-01-01

    This study investigates the use of dynamic a priori error information according to atmospheric moistness and the use of quality controls in temperature and water vapor profile retrievals from hyperspectral infrared (IR) sounders.Temperature and water vapor profiles are retrieved from Atmospheric InfraRed Sounder (AIRS) radiance measurements by applying a physical iterative method using regression retrieval as the first guess. Based on the dependency of first-guess errors on the degree of atmospheric moistness,the a priori first-guess errors classified by total precipitable water (TPW) are applied in the AIRS physical retrieval procedure.Compared to the retrieval results from a fixed a priori error,boundary layer moisture retrievals appear to be improved via TPW classification of a priori first-guess errors.Six quality control (QC)tests,which check non-converged or bad retrievals,large residuals,high terrain and desert areas,and large temperature and moisture deviations from the first guess regression retrieval,are also applied in the AIRS physical retrievals.Significantly large errors are found for the retrievals rejected by these six QCs,and the retrieval errors are substantially reduced via QC over land,which suggest the usefulness and high impact of the QCs,especially over land.In conclusion,the use of dynamic a priori error information according to atmospheric moistness,and the use of appropriate QCs dealing with the geographical information and the deviation from the first-guess as well as the conventional inverse performance are suggested to improve temperature and moisture retrievals and their applications.

  3. Sintering temperature and atmosphere modulated evolution of structure and luminescence of 2CaO-P2O5-B2O3

    DEFF Research Database (Denmark)

    Zhu, C. F.; Wang, J.; Ren, X. R.;

    2014-01-01

    -prepared phosphors and the relative content of these two phases is dependent on sintering temperature. CaBPO5 crystal favors the transition of 5D0 → 7F1 of Eu3+ ions, while BPO4 enhances the emission of 612 nm. This study gives insight into the correlation between optical properties and structure of the as......Europium doped 2CaO-P2O5-B2O3 phosphors prepared via high temperature solid state reactions are reported. The evolution of luminescence and structure of the phosphors induced by variation of sintering temperature and atmosphere is investigated using photoluminescence spectra and X-ray diffraction...... techniques. We found that the optical performance and structure of the phosphors are sensitive to the sintering temperature and atmosphere. The luminescence intensity due to 5D0 → 7F2 transition of Eu3+ is decreased with increasing sintering temperature. CaBPO5 and BPO4 crystals co-exist in the as...

  4. Monitoring middle-atmospheric dynamics using independent ground-based wind and temperature measurements at Reunion Island

    Science.gov (United States)

    Le Pichon, Alexis; Hauchecorne, Alain; Keckhut, Philippe; Khaykin, Sergey; Camas, Jean Pierre; Payen, Guillaume; Kämpfer, Niklaus; Rüfenacht, Rolf; Ceranna, Lars

    2016-04-01

    There are very few multi-instrumented sites in the tropics and particularly in the Southern Hemisphere. In these regions, developing atmospheric sounding methods in the middle and high-atmosphere provides valuable means to improve the physical representation of deep convection in atmospheric models (breaking of gravity waves, coupling between layers) and to better characterize large-scale atmospheric perturbations (cyclones, storms, tropical convection). The Maïdo observatory at Reunion Island (21°S, 55°E) offers trans-national access to host experiments or measurement campaigns for high resolution measurements of dynamic atmospheric processes in a wide range of altitude such as Rayleigh lidar, Doppler lidar, Modem radiosonde, or microwave Doppler spectro-radiometer (WIRA, operated by Institute of Applied Physics, University of Bern). Collocated to the existing instruments, a small aperture infrasound array (CEA) has been operating continuously since 2014. In the 0.1-1 Hz band, the coherent energy is dominated by microbarom signals resulting from the non-linear interaction of large swells systems which circulate along the Antarctic Circumpolar Current (ACC). The seasonal transition in the bearings along with the stratospheric general circulation between summer and winter is clearly noted. Interestingly, the semiannual oscillation (SAO) of the zonal stratospheric wind is well captured by infrasound measurements. It manifests by opposite ducts between 30 and 60 km that persist for several weeks during the equinox period. For the ARISE project (http://arise-project.eu/), this multi-technology site opens new perspectives to study the climatology of SAO as well as poorly resolved atmospheric disturbances of the tropical middle atmosphere where data coverage is sparse.

  5. The impact of temperature dependent CO2 cross section measurements: A role for heterogeneous chemistry in the atmosphere of Mars?

    Science.gov (United States)

    Anbar, A. D.; Allen, M.; Nair, H.; Leu, M-T.; Yung, Y. L.

    1992-01-01

    Carbon dioxide comprises over 95 percent of the Mars atmosphere, despite continuous photolysis of CO2 by solar ultraviolet (UV) radiation. Since the direct recombination of CO and O is spinforbidden, the chemical stability of CO2 in the Martian atmosphere is thought to be the result of a HO(x)-catalyzed recombination scheme. Thus the rate of CO oxidation is sensitive to the abundance and altitude distribution of OH, H, and HO2. Most Martian atmospheric models assume that HO(x) abundances are governed purely by gas phase chemistry. However, it is well established that reactive HO(x) radical are adsorbed by a wide variety of surfaces. The authors have combined laboratory studies of H, OH, and HO2 adsorption on inorganic surfaces, observational data of aerosol distributions, and an updated photochemical model to demonstrate that adsorption on either dust or ice aerosols is capable of reducing HO(x) abundances significantly, thereby retarding the rate of CO oxidation.

  6. Exoplanetary Atmospheres

    CERN Document Server

    Madhusudhan, Nikku; Fortney, Jonathan; Barman, Travis

    2014-01-01

    The study of exoplanetary atmospheres is one of the most exciting and dynamic frontiers in astronomy. Over the past two decades ongoing surveys have revealed an astonishing diversity in the planetary masses, radii, temperatures, orbital parameters, and host stellar properties of exoplanetary systems. We are now moving into an era where we can begin to address fundamental questions concerning the diversity of exoplanetary compositions, atmospheric and interior processes, and formation histories, just as have been pursued for solar system planets over the past century. Exoplanetary atmospheres provide a direct means to address these questions via their observable spectral signatures. In the last decade, and particularly in the last five years, tremendous progress has been made in detecting atmospheric signatures of exoplanets through photometric and spectroscopic methods using a variety of space-borne and/or ground-based observational facilities. These observations are beginning to provide important constraints...

  7. Accurate measurements and temperature dependence of the water vapor self-continuum absorption in the 2.1 μm atmospheric window.

    Science.gov (United States)

    Ventrillard, I; Romanini, D; Mondelain, D; Campargue, A

    2015-10-01

    In spite of its importance for the evaluation of the Earth radiative budget, thus for climate change, very few measurements of the water vapor continuum are available in the near infrared atmospheric windows especially at temperature conditions relevant for our atmosphere. In addition, as a result of the difficulty to measure weak broadband absorption signals, the few available measurements show large disagreements. We report here accurate measurements of the water vapor self-continuum absorption in the 2.1 μm window by Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) for two spectral points located at the low energy edge and at the center of the 2.1 μm transparency window, at 4302 and 4723 cm(-1), respectively. Self-continuum cross sections, CS, were retrieved with a few % relative uncertainty, from the quadratic dependence of the spectrum base line level measured as a function of water vapor pressure, between 0 and 16 Torr. At 296 K, the CS value at 4302 cm(-1) is found 40% higher than predicted by the MT_CKD V2.5 model, while at 4723 cm(-1), our value is 5 times larger than the MT_CKD value. On the other hand, these OF-CEAS CS values are significantly smaller than recent measurements by Fourier transform spectroscopy at room temperature. The temperature dependence of the self-continuum cross sections was also investigated for temperatures between 296 K and 323 K (23-50 °C). The derived temperature variation is found to be similar to that derived from previous Fourier transform spectrometer (FTS) measurements performed at higher temperatures, between 350 K and 472 K. The whole set of measurements spanning the 296-472 K temperature range follows a simple exponential law in 1/T with a slope close to the dissociation energy of the water dimer, D0 ≈ 1100 cm(-1). PMID:26450311

  8. Atmospheric Refraction

    CERN Document Server

    Nauenberg, Michael

    2016-01-01

    Calculations of atmospheric refraction are generally based on a simplified model of atmospheric density in the troposphere which assumes that the temperature decreases at a constant lapse rate from sea level up to a height equal to eleven km, and that afterwards it remains constant. In this model, the temperature divided by the lapse rate determines the length scale in the calculations for altitudes less than this height. But daily balloon measurements across the U.S.A. reveal that in some cases the air temperature actually increases from sea level up to a height of about one km, and only after reaching a plateau, it decreases at an approximately constant lapse rate. Moreover, in three examples considered here, the temperature does not remain constant at eleven km , but continues to decreases to a minimum at about sixteen kilometers , and then increases at higher altitudes at a lower rate. Calculations of atmospheric refraction based on this atmospheric data is compared with the results of simplified models.

  9. Comparison of co-located independent ground-based middle atmospheric wind and temperature measurements with numerical weather prediction models

    NARCIS (Netherlands)

    Le Pichon, A.; Assink, J.D.; Heinrich, P.; Blanc, E.; Charlton-Perez, A.; Lee, C.F.; Keckhut, P.; Hauchecorne, A.; Rufenacht, R.; Kampfer, N.; Drob, D.P.; Smets, P.S.M.; Evers, L.G.; Ceranna, L.; Pilger, C.; Ross, O.; Claud, C.

    2015-01-01

    High-resolution, ground-based and independent observations including co-located wind radiometer, lidar stations, and infrasound instruments are used to evaluate the accuracy of general circulation models and data-constrained assimilation systems in the middle atmosphere at northern hemisphere midlat

  10. A forward model for calculating the AMSR brightness temperatures of sea-ice and ocean as seen through the atmosphere

    DEFF Research Database (Denmark)

    Pedersen, Leif Toudal; Hofmann-Bang, Dorthe

    SSM/I retrievals, with ocean and atmosphere retrievals by Remote Sensing Systems, with SST data from the Ocean and Sea Ice SAF and with sea ice concentrations and MY-fractions of the NASA Team and Comiso Bootstrap sea ice algorithms. The forward model is the level 0 emissivity and radiative transfer...

  11. The Measurement of Tropospheric Temperature Profiles using Rayleigh-Brillouin Scattering: Results from Laboratory and Atmospheric Studies

    Science.gov (United States)

    Witschas, Benjamin; Reitebuch, Oliver; Lemmerz, Christian; Gomez Kableka, Pau; Kondratyev, Sergey; Gu, Ziyu; Ubachs, Wim

    2016-06-01

    In this letter, we suggest a new method for measuring tropospheric temperature profiles using Rayleigh-Brillouin (RB) scattering. We report on laboratory RB scattering measurements in air, demonstrating that temperature can be retrieved from RB spectra with an absolute accuracy of better than 2 K. In addition, we show temperature profiles from 2 km to 15.3 km derived from RB spectra, measured with a high spectral resolution lidar during daytime. A comparison with radiosonde temperature measurements shows reasonable agreement. In cloud-free conditions, the temperature difference reaches up to 5 K within the boundary layer, and is smaller than 2.5 K above. The statistical error of the derived temperatures is between 0.15 K and 1.5 K.

  12. Influence of temperature and atmosphere on the strength and elastic modulus of solid oxide fuel cell anode supports

    DEFF Research Database (Denmark)

    Ni, De Wei; Charlas, Benoit; Kwok, Kawai;

    2016-01-01

    for both the unreduced and reduced Ni(O)-YSZ anode supports. With increasing temperature, the strength and elastic modulus of the reduced Ni-YSZ specimens drop almost linearly. In contrast, the strength and elastic modulus of the unreduced NiO-YSZ remain almost constant over the investigated temperature...... need to be characterized to ensure reliable operation. In this study, the effect of reduction temperature on microstructural stability, high temperature strength and elastic modulus of Ni-YSZ anode supports were investigated. The statistical distribution of strength was determined from a large number...... of samples (∼30) at each condition to ensure high statistical validity. It is revealed that the microstructure and mechanical properties of the Ni-YSZ strongly depend on the reduction temperature. Further studies were conducted to investigate the temperature dependence of the strength and elastic modulus...

  13. Correlations of the first and second derivatives of atmospheric CO2 with global surface temperature and the El Nino-Southern Oscillation respectively

    CERN Document Server

    Leggett, L M W

    2014-01-01

    Understanding current global climate requires an understanding of trends both in Earth's atmospheric temperature and the El Nino-Southern Oscillation (ENSO), a characteristic large-scale distribution of warm water in the tropical Pacific Ocean and the dominant mode of year-to-year climate variability (Holbrook et al. 2009. However, despite much effort, the average projection of current climate models has become statistically significantly different from the observed 21st century global surface temperature trend (Fyfe 2013)and has failed to reflect the statistically significant evidence that annual-mean global temperature has not risen in the 21st century (Fyfe 2013, Kosaka 2013). Modelling also provides a wide range of predictions for future ENSO variability, some showing an increase, others a decrease and some no change (Guilyardi, et al. 2012; Bellenger, 2013). Here we present correlations which include the current era and do not have these drawbacks. The correlations arise as follows. First it has been sho...

  14. Influence of annealing atmosphere and temperature on photoluminescence of Tb 3+ or Eu 3+-activated zinc silicate thin film phosphors via sol-gel method

    Science.gov (United States)

    Zhang, Q. Y.; Pita, K.; Ye, W.; Que, W. X.

    2002-01-01

    Thin films of Zn 2SiO 4:Tb 3+ or Eu 3+ were deposited on silicon wafers by a sol-gel method. The films exhibited prominent green or red photoluminescence, due to the sharp and strong intra-4f n-shell electronic transitions. The thermogravimetric analysis curve shows a remarkable weight loss in the temperature range 50-400 ° C, and a slow loss at higher temperature. The increases in fluorescence intensity and decay lifetimes of rare-earth ions sensitive to microstructure and chemical components are attributed to OH removal, nano-crystallite formation and the increased surface roughness by treatment of temperature. Strongly enhanced photoluminescence was observed in samples annealed at 950 °C in a nitrogen atmosphere.

  15. Impact of Rain Snow Threshold Temperature on Snow Depth Simulation in Land Surface and Regional Atmospheric Models

    Institute of Scientific and Technical Information of China (English)

    WEN Lijuan; Nidhi NAGABHATLA; L(U) Shihua; Shih-Yu WANG

    2013-01-01

    This study investigates the impact of rain snow threshold (RST) temperatures on snow depth simulation using the Community Land Model (CLM) and the Weather Research and Forecasting model (WRF coupled with the CLM and hereafter referred to as WRF_CLM),and the difference in impacts.Simulations were performed from 17 December 1994 to 30 May 1995 in the French Alps.Results showed that both the CLM and the WRF_CLM were able to represent a fair simulation of snow depth with actual terrain height and 2.5℃ RST temperature.When six RST methods were applied to the simulation using WRF_CLM,the simulated snow depth was the closest to observations using 2.5℃ RST temperature,followed by that with Pipes',USACE,Kienzle's,Dai's,and 0℃ RST temperature methods.In the case of using CLM,simulated snow depth was the closest to the observation with Dai's method,followed by with USACE,Pipes',2.5℃ RST temperature,Kienzle's,and 0℃ RST temperature method.The snow depth simulation using the WRF_CLM was comparatively sensitive to changes in RST temperatures,because the RST temperature was not only the factor to partition snow and rainfall.In addition,the simulated snow related to RST temperature could induce a significant feedback by influencing the meteorological variables forcing the land surface model in WRF_CLM.In comparison,the above variables did not change with changes in RST in CLM.Impacts of RST temperatures on snow depth simulation could also be influenced by the patterns of temperature and precipitation,spatial resolution,and input terrain heights.

  16. Photoinduced superhydrophilicity of amorphous TiOx-like thin films by a simple room temperature sol-gel deposition and atmospheric plasma jet treatment

    International Nuclear Information System (INIS)

    A room temperature sol gel process of TTIP / iPrOH / H2O /HNO3 sol was applied for the deposition of functional Ti alkoxide thin films on glass and polymeric substrates (PEEK). The unheated – amorphous films become superhydrophilic after 7 minutes of UV exposure which deteriorates after one day of storage in dark, exhibiting stable amphiphilic behavior. Superhydrophilicity is also obtained after 5 min of atmospheric pressure Ar – O2 plasma jet treatment. As the plasma power and the oxygen content of the mixture of the treatment increase (70W, 3.2 -5% O2) the films high hydrophilicity is maintained for many days even in dark atmospheric conditions providing long term hydrophilic coatings

  17. Effects of elevated atmospheric CO2, prolonged summer drought and temperature increase on N2O and CH4 fluxes in a temperate heathland

    DEFF Research Database (Denmark)

    Carter, Mette Sustmann; Ambus, Per; Albert, Kristian Rost;

    2011-01-01

    In temperate regions, climate change is predicted to increase annual mean temperature and intensify the duration and frequency of summer droughts, which together with elevated atmospheric carbon dioxide (CO2) concentrations, may affect the exchange of nitrous oxide (N2O) and methane (CH4) between...... terrestrial ecosystems and the atmosphere. We report results from the CLIMAITE experiment, where the effects of these three climate change parameters were investigated solely and in all combinations in a temperate heathland. Field measurements of N2O and CH4 fluxes took place 1–2 years after the climate...... outweighed the positive effect of warming when analyzed across the study period. Emissions of N2O were generally low (...

  18. Photoinduced superhydrophilicity of amorphous TiOx-like thin films by a simple room temperature sol-gel deposition and atmospheric plasma jet treatment

    Science.gov (United States)

    Vrakatseli, V. E.; Pagonis, E.; Amanatides, E.; Mataras, D.

    2014-11-01

    A room temperature sol gel process of TTIP / iPrOH / H2O /HNO3 sol was applied for the deposition of functional Ti alkoxide thin films on glass and polymeric substrates (PEEK). The unheated - amorphous films become superhydrophilic after 7 minutes of UV exposure which deteriorates after one day of storage in dark, exhibiting stable amphiphilic behavior. Superhydrophilicity is also obtained after 5 min of atmospheric pressure Ar - O2 plasma jet treatment. As the plasma power and the oxygen content of the mixture of the treatment increase (70W, 3.2 -5% O2) the films high hydrophilicity is maintained for many days even in dark atmospheric conditions providing long term hydrophilic coatings.

  19. Research on the changes of the tidal force and the air temperature in the atmosphere of Lushan (China Ms7.0 earthquake

    Directory of Open Access Journals (Sweden)

    Ma Weiyu

    2015-01-01

    Full Text Available The cycle process of the tidal force of celestial body for Lushan M7.0 earthquake, occurred in Lushan county of Sichuan, China on April 20, 2013 was calculated. The earthquake occurred at the lowest point phase. It indicated that the type of seismogenic fault that the tide force acted on belonged to the thrust fault. According to the tidal cycle, the abnormal air temperature change was analyzed based on NCEP satellite data around the whole China before and after the earthquake. The result showed that the air temperature changed evidently with the tide force changing. In temporal, the change went through: initial air temperature rise → strength→ reaching abnormal peak→ gradually decline; in spatial, the abnormal area winded its way along the margin of the southern Qinghai-Tibet Plateau and went through: scattered→ conversion→ scattered procession. The procession was similar to the change procession of a rock breaking under the stress loading. This shows that the stress change of rock may cause the air temperature change in the atmosphere before and after earthquake. It indicated that the tidal force of celestial body could trigger the earthquake, when the tectonic stress reaches its critical broken point and the air temperature anomaly was proportional to the seismic tectonic stress change. It was useful to combine air temperature and tidal force in earthquake precursory.

  20. Estimation of the Total Atmospheric Water Vapor Content and Land Surface Temperature Based on AATSR Thermal Data

    Directory of Open Access Journals (Sweden)

    Rong Liu

    2008-03-01

    Full Text Available The total atmospheric water vapor content (TAWV and land surfacetemperature (LST play important roles in meteorology, hydrology, ecology and some otherdisciplines. In this paper, the ENVISAT/AATSR (The Advanced Along-Track ScanningRadiometer thermal data are used to estimate the TAWV and LST over the Loess Plateauin China by using a practical split window algorithm. The distribution of the TAWV isaccord with that of the MODIS TAWV products, which indicates that the estimation of thetotal atmospheric water vapor content is reliable. Validations of the LST by comparingwith the ground measurements indicate that the maximum absolute derivation, themaximum relative error and the average relative error is 4.0K, 11.8% and 5.0%respectively, which shows that the retrievals are believable; this algorithm can provide anew way to estimate the LST from AATSR data.

  1. Experimental investigation of anaerobic nitrogen fixation rates with varying pressure, temperature and metal concentration with application to the atmospheric evolution of early Earth and Mars.

    Science.gov (United States)

    Gupta, Prateek

    2012-07-01

    The atmosphere of the early Earth is thought to have been significantly different than the modern composition of 21% O2 and 78% N2, yet the planet has been clearly established as hosting microbial life as far back as 3.8 billion years ago. As such, constraining the atmospheric composition of the early Earth is fundamental to establishing a database of habitable atmospheric compositions. A similar argument can be made for the planet Mars, where nitrates have been hypothesized to exist in the subsurface. During the early period on Mars when liquid water was likely more abundant, life may have developed to take advantage of available nitrates and a biologically-driven Martian nitrogen cycle could have evolved. Early Earth atmospheric composition has been investigated numerically, but only recently has the common assumption of a pN2 different than modern been investigated. Nonetheless, these latest attempts fail to take into account a key atmospheric parameter: life. On modern Earth, nitrogen is cycled vigorously by biology. The nitrogen cycle likely operated on the early Earth, but probably differed in the metabolic processes responsible, dominantly due to the lack of abundant oxygen which stabilizes oxidized forms of N that drive de-nitrification today. Recent advances in evolutionary genomics suggest that microbial pathways that are relatively uncommon today (i.e. vanadium and iron-based nitrogen fixation) probably played important roles in the early N cycle. We quantitatively investigate in the laboratory the effects of variable pressure, temperature and metal concentration on the rates of anoxic nitrogen fixation, as possible inputs for future models investigating atmospheric evolution, and better understand the evolution of the nitrogen cycle on Earth. A common anaerobic methanogenic archaeal species with i) a fully sequenced genome, ii) all three nitrogenases (molybdenum, vanadium and iron-based) and iii) the ability to be genetically manipulated will be used as

  2. Experimental measurements of low temperature rate coefficients for neutral-neutral reactions of interest for atmospheric chemistry of Titan, Pluto and Triton: reactions of the CN radical.

    Science.gov (United States)

    Morales, Sébastien B; Le Picard, Sébastien D; Canosa, André; Sims, Ian R

    2010-01-01

    The kinetics of the reactions of cyano radical, CN (X2sigma+) with three hydrocarbons, propane (CH3CH2CH3), propene (CH3CH=CH2) and 1-butyne (CH[triple band]CCH2CH3) have been studied over the temperature range of 23-298 K using a CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme or Reaction Kinetics in Uniform Supersonic Flow) apparatus combined with the pulsed laser photolysis-laser induced fluorescence technique. These reactions are of interest for the cold atmospheres of Titan, Pluto and Triton, as they might participate in the formation of nitrogen and carbon bearing molecules, including nitriles, that are thought to play an important role in the formation of hazes and biological molecules. All three reactions are rapid with rate coefficients in excess of 10(-10) cm3 molecule(-1) s(-1) at the lowest temperatures of this study and show behaviour characteristic of barrierless reactions. Temperature dependences, different for each reaction, are compared to those used in the most recent photochemical models of Titan's atmosphere. PMID:21302546

  3. 2012/13 abnormal cold winter in Japan associated with Large-scale Atmospheric Circulation and Local Sea Surface Temperature over the Sea of Japan

    Science.gov (United States)

    Ando, Y.; Ogi, M.; Tachibana, Y.

    2013-12-01

    On Japan, wintertime cold wave has social, economic, psychological and political impacts because of the lack of atomic power stations in the era of post Fukushima world. The colder winter is the more electricity is needed. Wintertime weather of Japan and its prediction has come under the world spotlight. The winter of 2012/13 in Japan was abnormally cold, and such a cold winter has persisted for 3 years. Wintertime climate of Japan is governed by some dominant modes of the large-scale atmospheric circulations. Yasunaka and Hanawa (2008) demonstrated that the two dominant modes - Arctic Oscillation (AO) and Western Pacific (WP) pattern - account for about 65% of the interannual variation of the wintertime mean surface air temperature of Japan. A negative AO brings about cold winter in Japan. In addition, a negative WP also brings about cold winter in Japan. Looking back to the winter of 2012/13, both the negative AO and negative WP continued from October through December. If the previous studies were correct, it would have been extremely very cold from October through December. In fact, in December, in accordance with previous studies, it was colder than normal. Contrary to the expectation, in October and November, it was, however, warmer than normal. This discrepancy signifies that an additional hidden circumstance that heats Japan overwhelms these large-scale atmospheric circulations that cool Japan. In this study, we therefore seek an additional cause of wintertime climate of Japan particularly focusing 2012 as well as the AO and WP. We found that anomalously warm oceanic temperature surrounding Japan overwhelmed influences of the AO or WP. Unlike the inland climate, the island climate can be strongly influenced by surrounding ocean temperature, suggesting that large-scale atmospheric patterns alone do not determine the climate of islands. (a) Time series of a 5-day running mean AO index (blue) as defined by Ogi et al., (2004), who called it the SVNAM index. For

  4. New Discoveries Resulted from Lidar Investigation of Middle and Upper Atmosphere Temperature, Composition, Chemistry and Dynamics at McMurdo, Antarctica

    Science.gov (United States)

    Chu, X.; Yu, Z.; Fong, W.; Chen, C.; Huang, W.; Lu, X.; Gardner, C. S.; McDonald, A.; Fuller-Rowell, T. J.; Vadas, S.

    2013-12-01

    The scientific motivation to explore the neutral properties of the polar middle and upper atmosphere is compelling. Human-induced changes in the Earth's climate system are one of the most challenging social and scientific issues in this century. Besides monitoring climate change, to fully explore neutral-ion coupling in the critical region between 100 and 200 km is an objective of highest priority for the upper atmosphere science community. Meteorological sources of wave energy from the lower atmosphere are responsible for producing significant variability in the upper atmosphere. Energetic particles and fields originating from the magnetosphere regularly alter the state of the ionosphere. These influences converge through the tight coupling between the ionosphere plasma and neutral thermosphere gas in the space-atmosphere interaction region (SAIR). Unfortunately measurements of the neutral thermosphere are woefully incomplete and in critical need to advance our understanding of and ability to predict the SAIR. Lidar measurements of neutral thermospheric winds, temperatures and species can enable these explorations. To help address these issues, in December 2010 we deployed an Fe Boltzmann temperature lidar to McMurdo (77.8S, 166.7E), Antarctica via collaboration between the United States Antarctic Program and Antarctica New Zealand. Since then an extensive dataset (~3000 h) has been collected by this lidar during its first 32 months of operation, leading to several important new discoveries. The McMurdo lidar campaign will continue for another five years to acquiring long-term datasets for polar geospace research. In this paper we provide a comprehensive overview of the lidar campaign and scientific results, emphasizing several new discoveries in the polar middle and upper atmosphere research. In particular, the lidar has detected neutral Fe layers reaching 170 km in altitude, and derived neutral temperature from 30 to 170 km for the first time in the world. Such

  5. Grid-pattern formation of extracellular matrix on silicon by low-temperature atmospheric-pressure plasma jets for neural network biochip fabrication

    International Nuclear Information System (INIS)

    Grid patterns of extracellular matrices (ECMs) have been formed on silicon (Si) substrates with the use of low-temperature atmospheric-pressure plasma (APP) jets with metal stencil masks and neuron model cells have been successfully cultured on the patterned ECMs. Arrangement of living neuron cells on a microelectronics chip in a desired pattern is one of the major challenges for the fabrication of neuron-cell biochips. The APP-based technique presented in this study offers a cost-effective solution to this problem by providing a simple patterning method of ECMs, which act as biological interfaces between living cells and non-biological materials such as Si.

  6. Data in support of comparative analysis of strawberry proteome in response to controlled atmosphere and low temperature storage using a label-free quantification

    Directory of Open Access Journals (Sweden)

    Li Li

    2015-06-01

    Full Text Available To elucidate the mechanisms contributing to fruit responses to senescence and stressful environmental stimuli under low temperature (LT and controlled atmosphere (CA storage, a label-free quantitative proteomic investigation was conducted in strawberry (Fragaria ananassa, Duch. cv. ‘Akihime’. Postharvest volatile compounds were characterized following storage under different conditions. The observed post-storage protein expression profiles may be associated with delayed senescence features in strawberry [2]. A total of 454 proteins were identified in differentially treated strawberry fruits. Quantitative analysis, using normalized spectral counts, revealed 73 proteins common to all treatments, which formed three clusters in a hierarchical clustering analysis.

  7. Resistivity-temperature characteristics of sol gel YBa2Cu3Oy samples synthesized in flowing oxygen atmosphere

    Institute of Scientific and Technical Information of China (English)

    Zhou Zeng-Jun; Zhou Zuo-Wei; Zhou Liang-Yu; Lin Li; Li Xing-Guo; Feng Qing-Rong

    2004-01-01

    The relationship of resistivity versus synthesizing temperature of sol gel YBa2Cu3Oy samples was studied when prepared under flowing oxygen conditions. A set of high-temperature p-T curves was obtained for the whole process.After the sample finished the test measuring, its resistivity was ρ300=9.83 × 10-3Ω·cm at room temperature. The ρ-T curve also showed that the orthorhombic-tetragonal phase transformation of sol-gel YBa2Cu3Oy sample occurred at 581℃ for the sample in the rising temperature process, but at 613℃ in the cooling process, lower than that of the samples made by using the conventional powder metallurgy methods.

  8. Temperature, current meter, and other data from moored buoy as part of the GARP (Global Atmospheric Research Program) Atlantic Tropical Experiment (GATE) project, 30 July 1974 - 14 August 1974 (NODC Accession 7601675)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, current meter, and other data were collected using moored buoy from the CAPRICORNE from July 30, 1974 to August 14, 1974. Data were collected as part...

  9. Temperature profile and other data collected using microstructure profiler (JMSP) from the HAKUHO-MARU as part of the Coupled Ocean-Atmosphere Response Experiment (COARE), from 01 November 1992 - 30 November 1992 (NODC Accession 9600028)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and other data were collected using microstructure profiler (JMSP) from the HAKUHO-MARU in the TOGA Area - Pacific Ocean (30 N to 30 S) from...

  10. Underway pressure, temperature, and salinity data from the MOANA WAVE from the Pacific warm pool in support of the Coupled Ocean-Atmosphere Response Experiment (COARE) from 02 February 1993 to 21 February 1993 (NODC Accession 9600090)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pressure, temperature, and salinity data were collected while underway from the MOANA WAVE from the Pacific warm pool. Data were collected in support of the Coupled...

  11. Electronic quenching of OH(A) by water in atmospheric pressure plasmas and its influence on the gas temperature determination by OH(A-X) emission

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, Peter; Schram, Daan C [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven (Netherlands); Iza, Felipe; Kong, Michael G [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom); Guns, Peter; Lauwers, Daniel; Leys, Christophe [Department of Applied Physics, Ghent University, Jozef Plateaustraat 22, B-9000 Ghent (Belgium); Gonzalvo, Yolanda Aranda [Plasma and Surface Analysis Division, Hiden Analytical Ltd, 420 Europa Boulevard, Warrington WA5 7UN (United Kingdom)], E-mail: p.j.bruggeman@tue.nl

    2010-02-15

    In this paper it is shown that electronic quenching of OH(A) by water prevents thermalization of the rotational population distribution of OH(A). This means that the observed ro-vibrational OH(A-X) emission band is (at least partially) an image of the formation process and is determined not only by the gas temperature. The formation of negative ions and clusters for larger water concentrations can contribute to the non-equilibrium. The above is demonstrated in RF excited atmospheric pressure glow discharges in He-water mixtures in a parallel metal plate reactor by optical emission spectroscopy. For this particular case a significant overpopulation of high rotational states appears around 1000 ppm H{sub 2}O in He. The smallest temperature parameter of a non-Boltzmann (two-temperature) distribution fitted to the experimental spectrum of OH(A-X) gives a good representation of the gas temperature. Only the rotational states with the smallest rotational numbers (J {<=} 7) are thermalized and representative for the gas temperature.

  12. Electronic quenching of OH(A) by water in atmospheric pressure plasmas and its influence on the gas temperature determination by OH(A-X) emission

    International Nuclear Information System (INIS)

    In this paper it is shown that electronic quenching of OH(A) by water prevents thermalization of the rotational population distribution of OH(A). This means that the observed ro-vibrational OH(A-X) emission band is (at least partially) an image of the formation process and is determined not only by the gas temperature. The formation of negative ions and clusters for larger water concentrations can contribute to the non-equilibrium. The above is demonstrated in RF excited atmospheric pressure glow discharges in He-water mixtures in a parallel metal plate reactor by optical emission spectroscopy. For this particular case a significant overpopulation of high rotational states appears around 1000 ppm H2O in He. The smallest temperature parameter of a non-Boltzmann (two-temperature) distribution fitted to the experimental spectrum of OH(A-X) gives a good representation of the gas temperature. Only the rotational states with the smallest rotational numbers (J ≤ 7) are thermalized and representative for the gas temperature.

  13. Fertilizer P use efficiency in wheat under elevated atmospheric CO2 and temperature in subtropical India: a 32P tracer study

    International Nuclear Information System (INIS)

    A phytotron experiment was undertaken in which wheat was grown as a test crop under two levels of atmospheric CO2: ambient (385, μmol mol-1) and elevated (650, μmol mol-1); two levels of temperature: ambient (ambient air temperature of rabi season in Subtropical India) and elevated (ambient+3 deg C); and three levels of P: zero (control), 100% and 200% of recommended P dose to wheat. There were significant increases in total P and fertilizer P uptake by plant under singly elevated CO2 as well as concurrently elevated CO2 and temperature, with no significant change in %Pdff. As a consequence, fertilizer P use efficiency (PUE) also showed significant improvements both under the elevated CO2 alone as well as under combined elevation of CO2 and temperature. While this increase in fertilizer PUE was a welcome change under the projected levels of CO2 and temperature, low efficiency at higher doses of P application still remained a matter of concern. (author)

  14. Heat engines and heat pumps in a hydrostatic atmosphere: How surface pressure and temperature control wind power output and circulation cell size

    CERN Document Server

    Makarieva, A M; Nefiodov, A V; Sheil, D; Nobre, A D; Shearman, P L; Li, B -L

    2015-01-01

    The gross spatial features of the atmospheric kinetic energy budget are analytically investigated. Kinetic energy generation is evaluated in a hydrostatic atmosphere where the axisymmetric circulation cells are represented by Carnot cycles. The condition that kinetic energy generation is positive in the lower atmosphere is shown to limit the poleward cell extension via a relationship between the meridional differences in surface pressure and temperature $\\Delta p_s$ and $\\Delta T_s$: an upper limit to cell size exists when $\\Delta p_s$ increases sublinearly with $\\Delta T_s$. This is the case for the Hadley cells as demonstrated here using data from MERRA re-analysis. The limited cell size necessitates the appearance of heat pumps -- circulation cells with negative work output where the low-level air moves towards colder areas. These cells consume the positive work output of heat engines -- cells where the low-level air moves towards the warmer areas -- and can in principle drive the global efficiency of atmo...

  15. Effect of modified atmosphere and temperature abuse on the growth from spores and cereulide production of Bacillus weihenstephanensis in a cooked chilled meat sausage

    DEFF Research Database (Denmark)

    Thorsen, Line; Budde, Birgitte Bjørn; Koch, Anette Granly;

    2009-01-01

    The effect of modified atmosphere packaging (MAP) on the germination and growth of toxin producingpsychrotolerant Bacillus spp is not well described. A model agar system mimicking a cooked meat product wasused in initial experiments. Incubation at refrigeration temperature of 8 °C for 5 weeks of 26...... was observed at the earliest within 2 weeks when 20% CO2 was combined with 2% O2 and in 3 weeks when combined with "0"% O2 (the remaining atmosphere wasmade up from N2). Results were validated in a cookedmeat sausage model for two non-emetic and one emetic B. weihenstephanensis strain. The packaging film...... oxygen transfer rates (OTR) were 1.3 and 40 ml/m2/24 h and the atmospheres were 2% O2/20% CO2 and "0"% O2/20% CO2. Oxygen availability had a large impact on the growth from spores in the MAP meat sausage, only the most oxygen restricted condition (OTR of 1.3 ml/m2/24 h and "0"% O2/20 % CO2) inhibited...

  16. Sm1.5Sr0.5MO4 (M=Ni,Co,Fe) Cathode Catalysts for Ammonia Synthesis at Atmospheric Pressure and Low Temperature

    Institute of Scientific and Technical Information of China (English)

    XU,Gaochao; LIU,Ruiquan

    2009-01-01

    Sm1.5Sr0.5MO4 (M=Ni,Co,Fe) (SSM) catalysts were prepared by a sol-gel method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).Ammonia was synthesized from wet hydrogen and dry nitrogen at atmospheric pressure and low temperature (25-100 ℃) with applied voltage,using SSM as a cathode,Ni-Ce0.5Sm0.2O2-δ(Ni-SDC) as an anode,and silver-platinum film as a current collector,Nation proton exchange membrane as a proton permeating membrane.Several important factors on ammonia synthesis were investigated and the optimal synthetic temperature was found,at which the highest rate of evolution of ammonia was up to 1.05×10-8 mol·cm- 2·S-1.

  17. Influence of temperature on flammability limits of heat treating atmosphere%温度对热处理气氛可燃极限的影响

    Institute of Scientific and Technical Information of China (English)

    Dwyer John; Hansel James G.; Philips Tom; Chen Wayne; 侯学涛

    2011-01-01

    讨论了热处理气氛中常用气体成分的可燃极限,分析了上下可燃极限与温度的关系。提出了一个应用CAFT理论推断气氛可燃极限的方法,同时解释了温度对热处理炉安全操作的影响。%The flammability limits of gas constituents commonly used in heat treating atmospheres were discussed.The upper and lower flammability limits,with respect to temperature,were analyzed.A method was described for determining these limits using CAFT theory.This temperature factor and its impact on safe furnace practices were addressed.

  18. Effects of aging temperature on electrical conductivity and hardness of Cu-3 at. pct Ti alloy aged in a hydrogen atmosphere

    KAUST Repository

    Semboshi, S.

    2011-08-01

    To improve the balance of the electrical conductivity and mechanical strength for dilute Cu-Ti alloys by aging in a hydrogen atmosphere, the influence of aging temperature ranging from 673 K to 773 K (400 °C to 500 °C) on the properties of Cu-3 at. pct Ti alloy was studied. The Vickers hardness increases steadily with aging time and starts to fall at 3 hours at 773 K (500 °C), 10 hours at 723 K (450 °C), or over 620 hours at 673 K (400 °C), which is the same as the case of conventional aging in vacuum. The maximum hardness increases from 220 to 236 with the decrease of aging temperature, which is slightly lower than aging at the same temperature in vacuum. The electrical conductivity at the maximum hardness also increases from 18 to 32 pct of pure copper with the decrease of the temperature, which is enhanced by a factor of 1.3 to 1.5 in comparison to aging in vacuum. Thus, aging at 673 K (400 °C) in a hydrogen atmosphere renders fairly good balance of strength and conductivity, although it takes nearly a month to achieve. The microstructural changes during aging were examined by transmission electron microscopy (TEM) and atom-probe tomography (APT), it was confirmed that precipitation of the Cu4Ti phase occurs first and then particles of TiH2 form as the third phase, thereby efficiently removing the Ti solutes in the matrix.

  19. Sliding friction characteristics of different pairs of materials at room temperature in a He atmosphere and in vacuum

    International Nuclear Information System (INIS)

    In the framework of testing a refueling canal valve for fuel transfer systems of high-temperature reactors, investigations were carried out on metal alloys, CVD hard material coatings (carbides, nitrides) and solid lubricants at room temperature. These investigations are to discover suitable material combinations for the inner and outer wedge pairs of the expanding mechanism subjected to heavy strain and to provide general information about the applicability of material combinations with helium and vacuum conditions. The tribological fundamentals were prepared and 19 material combinations were tested at room temperature in helium and partly in vacuum with regard to a durability of 75x103 dynamic loading cycles. The tests showed that under the conditions mentioned and for the selected arrangement - wedge mechanism - material combinations can be chosen the working life of which will exceed the required durability. (orig./IHOE)

  20. Accurate measurements and temperature dependence of the water vapor self-continuum absorption in the 2.1 μm atmospheric window

    Energy Technology Data Exchange (ETDEWEB)

    Ventrillard, I.; Romanini, D.; Mondelain, D.; Campargue, A., E-mail: Alain.Campargue@ujf-grenoble.fr [LIPhy, Université Grenoble Alpes, F-38000 Grenoble (France); LIPhy, CNRS, F-38000 Grenoble (France)

    2015-10-07

    In spite of its importance for the evaluation of the Earth radiative budget, thus for climate change, very few measurements of the water vapor continuum are available in the near infrared atmospheric windows especially at temperature conditions relevant for our atmosphere. In addition, as a result of the difficulty to measure weak broadband absorption signals, the few available measurements show large disagreements. We report here accurate measurements of the water vapor self-continuum absorption in the 2.1 μm window by Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) for two spectral points located at the low energy edge and at the center of the 2.1 μm transparency window, at 4302 and 4723 cm{sup −1}, respectively. Self-continuum cross sections, C{sub S}, were retrieved with a few % relative uncertainty, from the quadratic dependence of the spectrum base line level measured as a function of water vapor pressure, between 0 and 16 Torr. At 296 K, the C{sub S} value at 4302 cm{sup −1} is found 40% higher than predicted by the MT-CKD V2.5 model, while at 4723 cm{sup −1}, our value is 5 times larger than the MT-CKD value. On the other hand, these OF-CEAS C{sub S} values are significantly smaller than recent measurements by Fourier transform spectroscopy at room temperature. The temperature dependence of the self-continuum cross sections was also investigated for temperatures between 296 K and 323 K (23-50 °C). The derived temperature variation is found to be similar to that derived from previous Fourier transform spectrometer (FTS) measurements performed at higher temperatures, between 350 K and 472 K. The whole set of measurements spanning the 296-472 K temperature range follows a simple exponential law in 1/T with a slope close to the dissociation energy of the water dimer, D{sub 0} ≈ 1100 cm{sup −1}.

  1. New low-temperature preparations of some simple and mixed co and ni dispersed sulfides and their chemical behavior in reducing atmosphere.

    Science.gov (United States)

    Bezverkhyy, I; Danot, M; Afanasiev, P

    2003-03-10

    A series of simple (CoS(2), Co(9)S(8), NiS(2), NiS, Ni(3)S(2)) and mixed sulfides (NiCo(2)S(4), Ni(0.33)Co(0.67)S(2), Ni(3)Co(6)S(8), CuCo(2)S(4), Cu(0.33)Co(0.67)S(2)) was prepared using low-temperature procedures. To obtain the mixed sulfides, the mixtures of the solutions of the corresponding salts were precipitated by Na(2)S and then heated in a sulfiding atmosphere at 300 degrees C. It has been found that the product phase composition depends on the sulfiding atmosphere. Using a H(2)S/Ar mixture leads to pyrite type sulfides, whereas treatment in H(2)S/H(2) flow allowed the preparation of Ni-Co and Cu-Co thiospinels. The as prepared highly dispersed single-phase materials were characterized by X-ray powder diffraction, scanning electron microscopy, temperature-programmed reduction (TPR), elemental analysis, and BET surface area measurements.

  2. Numerical studies of independent control of electron density and gas temperature via nonlinear coupling in dual-frequency atmospheric pressure dielectric barrier discharge plasmas

    Science.gov (United States)

    Zhang, Z. L.; Nie, Q. Y.; Wang, Z. B.; Gao, X. T.; Kong, F. R.; Sun, Y. F.; Jiang, B. H.

    2016-07-01

    Dielectric barrier discharges (DBDs) provide a promising technology of generating non-equilibrium cold plasmas in atmospheric pressure gases. For both application-focused and fundamental studies, it is important to explore the strategy and the mechanism for enabling effective independent tuning of key plasma parameters in a DBD system. In this paper, we report numerical studies of effects of dual-frequency excitation on atmospheric DBDs, and modulation as well as separate tuning mechanism, with emphasis on dual-frequency coupling to the key plasma parameters and discharge evolution. With an appropriately applied low frequency to the original high frequency, the numerical calculation demonstrates that a strong nonlinear coupling between two frequencies governs the process of ionization and energy deposition into plasma, and thus raises the electron density significantly (e.g., three times in this case) in comparisons with a single frequency driven DBD system. Nevertheless, the gas temperature, which is mainly determined by the high frequency discharge, barely changes. This method then enables a possible approach of controlling both averaged electron density and gas temperature independently.

  3. Sensitivity of Middle Atmospheric Temperature and Circulation in the UIUC Mesosphere-Stratosphere-Troposphere GCM to the Treatment of Subgrid-Scale Gravity-Wave Breaking

    Science.gov (United States)

    Yang, Fanglin; Schlesinger, Michael E.; Andranova, Natasha; Zubov, Vladimir A.; Rozanov, Eugene V.; Callis, Lin B.

    2003-01-01

    The sensitivity of the middle atmospheric temperature and circulation to the treatment of mean- flow forcing due to breaking gravity waves was investigated using the University of Illinois at Urbana-Champaign 40-layer Mesosphere-Stratosphere-Troposphere General Circulation Model (MST-GCM). Three GCM experiments were performed. The gravity-wave forcing was represented first by Rayleigh friction, and then by the Alexander and Dunkerton (AD) parameterization with weak and strong breaking effects of gravity waves. In all experiments, the Palmer et al. parameterization was included to treat the breaking of topographic gravity waves in the troposphere and lower stratosphere. Overall, the experiment with the strong breaking effect simulates best the middle atmospheric temperature and circulation. With Rayleigh friction and the weak breaking effect, a large warm bias of up to 60 C was found in the summer upper mesosphere and lower thermosphere. This warm bias was linked to the inability of the GCM to simulate the reversal of the zonal winds from easterly to westerly crossing the mesopause in the summer hemisphere. With the strong breaking effect, the GCM was able to simulate this reversal, and essentially eliminated the warm bias. This improvement was the result of a much stronger meridional transport circulation that possesses a strong vertical ascending branch in the summer upper mesosphere, and hence large adiabatic cooling. Budget analysis indicates that 'in the middle atmosphere the forces that act to maintain a steady zonal-mean zonal wind are primarily those associated with the meridional transport circulation and breaking gravity waves. Contributions from the interaction of the model-resolved eddies with the mean flow are small. To obtain a transport circulation in the mesosphere of the UIUC MST-GCM that is strong enough to produce the observed cold summer mesopause, gravity-wave forcing larger than 100 m/s/day in magnitude is required near the summer mesopause. In

  4. Influence of small-scale North Atlantic sea surface temperature patterns on the marine boundary layer and free troposphere: a study using the atmospheric ARPEGE model

    Science.gov (United States)

    Piazza, Marie; Terray, Laurent; Boé, Julien; Maisonnave, Eric; Sanchez-Gomez, Emilia

    2016-03-01

    A high-resolution global atmospheric model is used to investigate the influence of the representation of small-scale North Atlantic sea surface temperature (SST) patterns on the atmosphere during boreal winter. Two ensembles of forced simulations are performed and compared. In the first ensemble (HRES), the full spatial resolution of the SST is maintained while small-scale features are smoothed out in the Gulf Stream region for the second ensemble (SMTH). The model shows a reasonable climatology in term of large-scale circulation and air-sea interaction coefficient when compared to reanalyses and satellite observations, respectively. The impact of small-scale SST patterns as depicted by differences between HRES and SMTH shows a strong meso-scale local mean response in terms of surface heat fluxes, convective precipitation, and to a lesser extent cloudiness. The main mechanism behind these statistical differences is that of a simple hydrostatic pressure adjustment related to increased SST and marine atmospheric boundary layer temperature gradient along the North Atlantic SST front. The model response to small-scale SST patterns also includes remote large-scale effects: upper tropospheric winds show a decrease downstream of the eddy-driven jet maxima over the central North Atlantic, while the subtropical jet exhibits a significant northward shift in particular over the eastern Mediterranean region. Significant changes are simulated in regard to the North Atlantic storm track, such as a southward shift of the storm density off the coast of North America towards the maximum SST gradient. A storm density decrease is also depicted over Greenland and the Nordic seas while a significant increase is seen over the northern part of the Mediterranean basin. Changes in Rossby wave breaking frequencies and weather regimes spatial patterns are shown to be associated to the jets and storm track changes.

  5. Electron Density and Temperature Measurement by Stark Broadening in a Cold Argon Arc-Plasma Jet at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qiuping; CHENG Cheng; MENG Yuedong

    2009-01-01

    Determination of both the electron density and temperature simultaneously in a cold argon arc-plasma jet by analyzing the Stark broadening of two different emission lines is presented.This method is based on the fact that the Stark broadening of different lines has a different dependence on the electron density and temperature.Therefore,a comparison of two or more line broadenings allows us to diagnose the electron density and temperature simultaneously.In this study we used the first two Balmer series hydrogen lines H_α and H_β for their large broadening width.For this purpose,a small amount of hydrogen was introduced into the discharge gas.The results of the Gigosos-Cardenoso computational model,considering more relevant processes for the hydrogen Balmer lines,is used to process the experimental data.With this method,we obtained reliable electron density and temperature,1.88 ×10 ~(15) cm~(-3 )and 13000 K,respectively.Possible sources of error were also analyzed.

  6. The Propagation of Variation in Glucosinolate Levels as effected by Controlled Atmosphere and Temperature in a Broccoli Batch

    NARCIS (Netherlands)

    Schouten, R.E.; Zhang, X.; Tijskens, L.M.M.; Kooten, van O.

    2008-01-01

    Broccoli combines high levels of vitamins, fibres and glucosinolates (GLS) with a low calorie count. GLS are precursors for the characteristic broccoli flavour and have anti-carcinogenic properties. This study describes the effect of controlled atmo¬sphere (CA) and temperature on GLS concentrations

  7. Effect of particulate matter, atmospheric gases, temperature, and humidity on respiratory and circulatory diseases’ trends in Lisbon, Portugal

    NARCIS (Netherlands)

    Freitas, M.C.; Pacheco, A.M.G.; Verburg, T.G.; Wolterbeek, H.T.

    2009-01-01

    This study addresses the significant effects of both well-known contaminants (particles, gases) and less-studied variables (temperature, humidity) on serious, if relatively common, respiratory and circulatory diseases. The area of study is Lisbon, Portugal, and time series of health outcome (daily a

  8. Low-frequency variations in surface atmospheric humidity, temperature, and precipitation: Inferences from reanalyses and monthly gridded observational data sets

    Science.gov (United States)

    Simmons, A. J.; Willett, K. M.; Jones, P. D.; Thorne, P. W.; Dee, D. P.

    2010-01-01

    Evidence is presented of a reduction in relative humidity over low-latitude and midlatitude land areas over a period of about 10 years leading up to 2008, based on monthly anomalies in surface air temperature and humidity from comprehensive European Centre for Medium-Range Weather Forecasts reanalyses (ERA-40 and ERA-Interim) and from Climatic Research Unit and Hadley Centre analyses of monthly station temperature data (CRUTEM3) and synoptic humidity observations (HadCRUH). The data sets agree well for both temperature and humidity variations for periods and places of overlap, although the average warming over land is larger for the fully sampled ERA data than for the spatially and temporally incomplete CRUTEM3 data. Near-surface specific humidity varies similarly over land and sea, suggesting that the recent reduction in relative humidity over land may be due to limited moisture supply from the oceans, where evaporation has been limited by sea surface temperatures that have not risen in concert with temperatures over land. Continental precipitation from the reanalyses is compared with a new gauge-based Global Precipitation Climatology Centre (GPCC) data set, with the combined gauge and satellite products of the Global Precipitation Climatology Project (GPCP) and the Climate Prediction Center (CPC), Merged Analysis of Precipitation (CMAP), and with CPC's independent gauge analysis of precipitation over land (PREC/L). The reanalyses agree best with the new GPCC and latest GPCP data sets, with ERA-Interim significantly better than ERA-40 at capturing monthly variability. Shifts over time in the differences among the precipitation data sets make it difficult to assess their longer-term variations and any link with longer-term variations in humidity.

  9. An evaluation of uncertainties in monitoring middle atmosphere temperatures with the ground-based lidar network in support of space observations

    Science.gov (United States)

    Keckhut, P.; Randel, W. J.; Claud, C.; Leblanc, T.; Steinbrecht, W.; Funatsu, B. M.; Bencherif, H.; McDermid, I. S.; Hauchecorne, A.; Long, C.; Lin, R.; Baumgarten, G.

    2011-04-01

    The capability of the longest lidar data sets to monitor long-term temperature changes have been evaluated through comparisons with the successive Stratospheric Sounder Units (SSU) onboard NOAA satellites. Cross-consistency investigations between SSU and the lidar network can be considered as a first attempt to demonstrate how the synergistic use of space and ground-based instruments could provide reliable monitoring of the temperature of the middle atmosphere. The breakdown of the temperature cooling trend, and the following flattening observed in the satellite temperature series, is qualitatively confirmed by the lidars. However, there are still large differences that can either be due to SSU continuity (orbit drifts or weighting function modifications) or lidar operation changes (time of measurements, accuracy, sampling, etc.). SSU vertical weighting functions have been taken into account for comparisons. Some discontinuity events cannot be explained by the SSU weighting function drifts due to CO2. For the upper channels of SSU (peaking around 50 km), the results are probably sensitive to the mesospheric part of the lidar profiles that can explain some discontinuities. Tropical lidar stations show clear inter-annual differences with the SSU channels covering the lowest altitude range that needs further investigations to understand if the origin is instrumental or geophysical. An attempt to derive non-linear trends with combinations of linear, hockey stick, and quadratic functions has been made. While the quadratic term is not highly significant, this approach allows the derivation of a better quantification of the linear trend terms.

  10. Experimental Study of Temperatures of Atmospheric-Pressure Nonequilibrium Ar/N2 Plasma Jets and Poly(ethylene terephtalate)-Surface Processing

    Science.gov (United States)

    Yuji, Toshifumi; Suzaki, Yoshifumi; Yamawaki, Takashi; Sakaue, Hiroyuki; Akatsuka, Hiroshi

    2007-02-01

    To understand the mechanism of surface processing using atmospheric-pressure nonequilibrium plasma jets, we measured the vibrational and rotational temperatures in the plasmas by optical emission spectroscopy. Plasma was excited using a high-frequency pulsed power supply, using a gas mixture of Ar (20 L/min) and N2 (0.1 to 0.5 L/min) as the plasma gas, and changing the flow rate of N2 gas at an input power of 100 W and plasma frequencies of 5 and 10 kHz. The measured vibrational and rotational temperatures in plasma were approximately 0.18 to 0.26 eV and 0.21 to 0.28 eV, respectively. We also carried out a plasma surface processing of polyethylene terephtalate film to measure the changes in water contact angle before and after the processing. We found a monotonic decrease in the contact angle of the processed poly(ethylene terephtalate) (PET) film as plasma rotational temperature increased. It is concluded that the hydrophilicity of the PET surface increases with plasma rotational temperature.

  11. High temperature corrosion studies. A. Iron: based superalloy in SO/sub 2//O/sub 2/ atmospheres. B. Gas: solid reaction with formation of volatile species

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T.K.

    1980-03-01

    The thermogravimetric method was used to study high temperature corrosion under SO/sub 2//O/sub 2/ atmosphere applied to Armco 18SR alloys with different heat treatment histories, Armco T310 and pure chromium between 750 and 1100/sup 0/C. The weight gain follows the parabolic rate law. The volatilization of the protective Cr/sub 2/O/sub 3/ layer via formation of CrO/sub 3/ was taken into account above 900/sup 0/C for long time runs. The parabolic rate and the volatilization rate, derived from fitting the experimental data to the modified Tedmon's non-linear model, were correlated using the Arrhenius equation. Armco 18SR-C has the best corrosion resistance of the Armco 18SR alloys. Armco T310 is not protective at high temperatures. The available rate data on the oxidation of chromium oxide, chlorination of chromium, oxidation-chlorination of chromium oxide, chlorination of nickel and chlorination of iron were found to be predictable. The calculation of high temperature volatilization rate was performed using the available fluid correlation equations and the Lennard-Jones parameters derived from the molecule with similar structure and from the low temperature viscosity measurement. The lower predicted volatilization rate is due to the use of the Chapman-Enskog equation with the Lennard-Jones parameters mostly derived from the low temperature viscosity measurement. This was substantiated by comparing the reliable high temperature diffusion rate in the literature with the above mentioned calculational method. The experimental volatilization rates of this study are compared with the other related studies and the mass transfer predictions.

  12. Turbulent Transfer Coefficients and Calculation of Air Temperature inside Tall Grass Canopies in Land Atmosphere Schemes for Environmental Modeling.

    Science.gov (United States)

    Mihailovic, D. T.; Alapaty, K.; Lalic, B.; Arsenic, I.; Rajkovic, B.; Malinovic, S.

    2004-10-01

    A method for estimating profiles of turbulent transfer coefficients inside a vegetation canopy and their use in calculating the air temperature inside tall grass canopies in land surface schemes for environmental modeling is presented. The proposed method, based on K theory, is assessed using data measured in a maize canopy. The air temperature inside the canopy is determined diagnostically by a method based on detailed consideration of 1) calculations of turbulent fluxes, 2) the shape of the wind and turbulent transfer coefficient profiles, and 3) calculation of the aerodynamic resistances inside tall grass canopies. An expression for calculating the turbulent transfer coefficient inside sparse tall grass canopies is also suggested, including modification of the corresponding equation for the wind profile inside the canopy. The proposed calculations of K-theory parameters are tested using the Land Air Parameterization Scheme (LAPS). Model outputs of air temperature inside the canopy for 8 17 July 2002 are compared with micrometeorological measurements inside a sunflower field at the Rimski Sancevi experimental site (Serbia). To demonstrate how changes in the specification of canopy density affect the simulation of air temperature inside tall grass canopies and, thus, alter the growth of PBL height, numerical experiments are performed with LAPS coupled with a one-dimensional PBL model over a sunflower field. To examine how the turbulent transfer coefficient inside tall grass canopies over a large domain represents the influence of the underlying surface on the air layer above, sensitivity tests are performed using a coupled system consisting of the NCEP Nonhydrostatic Mesoscale Model and LAPS.

  13. Hydroxyl-Exchanged Nanoporous Ionic Copolymer toward Low-Temperature Cycloaddition of Atmospheric Carbon Dioxide into Carbonates.

    Science.gov (United States)

    Guo, Zengjing; Cai, Xiaochun; Xie, Jingyan; Wang, Xiaochen; Zhou, Yu; Wang, Jun

    2016-05-25

    An ionic copolymer catalyst with nanopores, large surface area, high ionic density, and superior basicity was prepared via the radical copolymerization of amino-functionalized ionic liquid bromide and divinylbenzene, followed with a hydroxyl exchange for removing bromonium. Evaluated in chemical fixation of CO2 with epoxides into cyclic carbonates in the absence of any solvent and basic additive, the nanoporous copolymer catalyst showed high and stable activity, superior to various control catalysts including the halogen-containing analogue. Further, high yields were obtained over a wide scope of substrates including aliphatic long carbon-chain alkyl epoxides and internal epoxide, even under atmospheric pressure and less than 100 °C for the majority of the substrates. On the basis of in situ Fourier transform infrared (FT-IR) investigation and density functional theory (DFT) calculation for the reaction intermediates, we proposed a possible reaction mechanism accounting for the superior catalytic activity of the ionic copolymer. The specifically prepared ionic copolymer material of this work features highly stable, noncorrosive, and sustainable catalysis and, thus, may be a new possibility for efficient chemical fixation of CO2 since it is an environmentally friendly, metal-free solid catalyst. PMID:27142654

  14. Atmospheric reaction of Cl + methacrolein: a theoretical study on the mechanism, and pressure- and temperature-dependent rate constants.

    Science.gov (United States)

    Sun, Cuihong; Xu, Baoen; Zhang, Shaowen

    2014-05-22

    Methacrolein is a major degradation product of isoprene, the reaction of methacrolein with Cl atoms may play some roles in the degradation of isoprene where these species are relatively abundant. However, the energetics and kinetics of this reaction, which govern the reaction branching, are still not well understood so far. In the present study, two-dimensional potential energy surfaces were constructed to analyze the minimum energy path of the barrierless addition process between Cl and the C═C double bond of methacrolein, which reveals that the terminal addition intermediate is directly formed from the addition reaction. The terminal addition intermediate can further yield different products among which the reaction paths abstracting the aldehyde hydrogen atom and the methyl hydrogen atom are dominant reaction exits. The minimum reaction path for the direct aldehydic hydrogen atom abstraction is also obtained. The reaction kinetics was calculated by the variational transition state theory in conjunction with the master equation method. From the theoretical model we predicted that the overall rate constant of the Cl + methacrolein reaction at 297 K and atmospheric pressure is koverall = 2.3× 10(-10) cm(3) molecule(-1) s(-1), and the branching ratio of the aldehydic hydrogen abstraction is about 12%. The reaction is pressure dependent at P pressure limit at about 100 Torr. The calculated results could well account for the experimental observations.

  15. 大气压空气等离子体羽的振动温度研究%Vibrational Temperature of Plasma Plume in Atmospheric Pressure Air

    Institute of Scientific and Technical Information of China (English)

    李雪辰; 常媛媛; 贾鹏英; 赵欢欢; 鲍文婷

    2013-01-01

    A tri-electrode discharge device was designed in a dielectric barrier discharge configurations to generate a fairly large volume plasma plume in atmospheric pressure air.The discharge characteristics of the plasma plume were investigated by an optical method.The discharge emission from the plasma plume was collected by a photomultiplier tube.It was found that the number of discharge pulse per cycle of the applied voltage increased with increasing the peak value of the applied voltage.The emission spectra of the plasma plume were collected by a spectrometer.The vibrational temperature was calculated by fitting the experimental data to the theoretical one.Results showed that the vibrational temperature of the plasma plume decreases with increasing the Up.Spatially resolved measurement of the vibrational temperature was also conducted on the plasma plume with the same method.Results showed that the vibrational temperature increases firstly and then decreases with increasing distance from the nozzle.The vibrational temperature reachs its maximum when the distance is 5.4 mm from the nozzle.These experimental phenomena were analyzed qualitatively based on the discharge theory.These results have important significance for the industrial applications of the plasma plume in atmospheric pressure air.%利用三电极介质阻挡放电装置,在大气压空气中产生了较大体积的等离子体羽.采用光学方法对该等离子体羽的特性进行了研究.发现随着外加电压峰值增加,每个外加电压周期的放电脉冲个数增加.通过采集等离子体羽的发射光谱,空间分辨地研究了放电等离子体羽的振动温度.结果表明等离子体羽的振动温度随着外加电压峰值的增加而减小;随着远离喷嘴的距离的增加,等离子体振动温度先增加后减小,当距离喷嘴5.4mm时振动温度达到最高值.对上述现象进行了定性分析.研究结果对大气压空气等离子体羽在杀菌消毒等领域的应用具有重要意义.

  16. Conversion of emitted dimethyl sulfide into eco-friendly species using low-temperature atmospheric argon micro-plasma system

    International Nuclear Information System (INIS)

    Highlights: ► Dimethyl sulfide (DMS) was fully decomposed by two-electrode Ar micro-plasma. ► The reaction of DMS/Ar resulted in forming solid compound and gaseous product. ► The C-, H- and S-containing solid compound was fixed on the quartz inner tube. ► The H2-, CS2-, and H2S-gaseous products were possibly recyclable and trapped. ► The dissociation mechanism and treatment efficiency of DMS were also discussed. - Abstract: A custom-made atmospheric argon micro-plasma system was employed to dissociate dimethyl sulfide (DMS) into a non-foul-smelling species. The proposed system takes the advantages of low energy requirement and non-thermal process with a constant flow rate at ambient condition. In the experiments, the compositions of DMS/argon plasma, the residual gaseous phases, and solid precipitates were respectively characterized using an optical emission spectrometer, various gas-phase analyzers, and X-ray photoemission spectroscopy. For 400 ppm DMS introduced into argon plasma with two pairs of electrodes (90 W), a complete decomposition of DMS was achieved; the DMS became converted into excited species such as C*, C2*, H*, and CH*. When gaseous products were taken away from the treatment area, the excited species tended to recombine and form stable compounds or species, which formed as solid particles and gaseous phases. The solid deposition was likely formed by the agglomeration of C-, H-, and S-containing species that became deposited on the quartz inner tube. For the residual gaseous phases, low-molecular-weight segments mostly recombined into relatively thermodynamic stable species, such as hydrogen, hydrogen sulfide, and carbon disulfide. The dissociation mechanism and treatment efficiency are discussed, and a treatment of converting DMS into H2-, CS2-, and H2S-dominant by-products is proposed.

  17. A case study of effects of atmospheric boundary layer turbulence, wind speed, and stability on wind farm induced temperature changes using observations from a field campaign

    Science.gov (United States)

    Xia, Geng; Zhou, Liming; Freedman, Jeffrey M.; Roy, Somnath Baidya; Harris, Ronald A.; Cervarich, Matthew Charles

    2016-04-01

    Recent studies using satellite observations show that operational wind farms in west-central Texas increase local nighttime land surface temperature (LST) by 0.31-0.70 °C, but no noticeable impact is detected during daytime, and that the diurnal and seasonal variations in the magnitude of this warming are likely determined by those in the magnitude of wind speed. This paper further explores these findings by using the data from a year-long field campaign and nearby radiosonde observations to investigate how thermodynamic profiles and surface-atmosphere exchange processes work in tandem with the presence of wind farms to affect the local climate. Combined with satellite data analyses, we find that wind farm impacts on LST are predominantly determined by the relative ratio of turbulence kinetic energy (TKE) induced by the wind turbines compared to the background TKE. This ratio explains not only the day-night contrast of the wind farm impact and the warming magnitude of nighttime LST over the wind farms, but also most of the seasonal variations in the nighttime LST changes. These results indicate that the diurnal and seasonal variations in the turbine-induced turbulence relative to the background TKE play an essential role in determining those in the magnitude of LST changes over the wind farms. In addition, atmospheric stability determines the sign and strength of the net downward heat transport as well as the magnitude of the background TKE. The study highlights the need for better understanding of atmospheric boundary layer and wind farm interactions, and for better parameterizations of sub-grid scale turbulent mixing in numerical weather prediction and climate models.

  18. Midwestern streamflow, precipitation, and atmospheric vorticity influenced by Pacific sea-surface temperatures and total solar-irradiance variations

    Science.gov (United States)

    Perry, C.A.

    2006-01-01

    A solar effect on streamflow in the Midwestern United States is described and supported in a six-step physical connection between total solar irradiance (TSI), tropical sea-surface temperatures (SSTs), extratropical SSTs, jet-stream vorticity, surface-layer vorticity, precipitation, and streamflow. Variations in the correlations among the individual steps indicate that the solar/hydroclimatic mechanism is complex and has a time element (lag) that may not be constant. Correct phasing, supported by consistent spectral peaks between 0.092 and 0.096 cycles per year in all data sets within the mechanism is strong evidence for its existence. A significant correlation exists between total solar irradiance and the 3-year moving average of annual streamflow for Iowa (R = 0.67) and for the Mississippi River at St Louis, Missouri (R = 0.60), during the period 1950-2000. Published in 2005 by John Wiley & Sons, Ltd.

  19. High electron mobility thin-film transistors based on Ga{sub 2}O{sub 3} grown by atmospheric ultrasonic spray pyrolysis at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Stuart R., E-mail: s.thomas09@imperial.ac.uk, E-mail: thomas.anthopoulos@imperial.ac.uk; Lin, Yen-Hung; Faber, Hendrik; Anthopoulos, Thomas D., E-mail: s.thomas09@imperial.ac.uk, E-mail: thomas.anthopoulos@imperial.ac.uk [Department of Physics, Blackett Laboratory, Imperial College London, London SW7 2BW (United Kingdom); Adamopoulos, George [Department of Engineering, Engineering Building, Lancaster University, Bailrigg, Lancaster LA1 4YR (United Kingdom); Sygellou, Labrini [Institute of Chemical Engineering and High Temperature Processes (ICEHT), Foundation of Research and Technology Hellas (FORTH), Stadiou Strasse Platani, P.O. Box 1414, Patras GR-265 04 (Greece); Stratakis, Emmanuel [Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion 71003 (Greece); Materials Science and Technology Department, University, of Crete, Heraklion 71003 (Greece); Pliatsikas, Nikos; Patsalas, Panos A. [Laboratory of Applied Physics, Department of Physics, Aristotle University of Thessaloniki, Thessaloniki GR-54124 (Greece)

    2014-09-01

    We report on thin-film transistors based on Ga{sub 2}O{sub 3} films grown by ultrasonic spray pyrolysis in ambient atmosphere at 400–450 °C. The elemental, electronic, optical, morphological, structural, and electrical properties of the films and devices were investigated using a range of complementary characterisation techniques, whilst the effects of post deposition annealing at higher temperature (700 °C) were also investigated. Both as-grown and post-deposition annealed Ga{sub 2}O{sub 3} films are found to be slightly oxygen deficient, exceptionally smooth and exhibit a wide energy bandgap of ∼4.9 eV. Transistors based on as-deposited Ga{sub 2}O{sub 3} films show n-type conductivity with the maximum electron mobility of ∼2 cm{sup 2}/V s.

  20. Interannual Variability and Trends in Daily Temperature and Precipitation Extreme Indices in Finland in Relation to Atmospheric Circulation Patterns, 1961-2011

    Science.gov (United States)

    Irannezhad, Masoud; Kløve, Bjørn

    2016-04-01

    Daily temperature (minimum and maximum) and precipitation datasets applied at regular grid points (10×10 km2) throughout Finland for 1961-2011 were analyzed with the aim to evaluate variability and trends in weather extremes on both national and spatial scale of the country and their relationships with atmospheric circulation patterns (ACPs). Recommending by the Expert Team on Climate Change Detection and Indices (ETCCDI), the extreme indices considered for daily temperature were frost days (FD), summer days (SD) and ice days (ID); and for daily precipitation were heavy precipitation days (R10), consecutive dry days (CDD), consecutive wet days (CWD), highest 1-day precipitation amount (RX1day), simple daily intensity index (SDII) and precipitation fraction due to 95th percentile of the reference period (R95pTOT). This study used the well-known influential ACPs for Finland climate variability: North Atlantic Oscillation (NAO), Arctic Oscillation (AO), East Atlantic (EA), East Atlantic/West Russia (EA/WR), Polar (POL), Scandinavia (SCA). The non-parametric Mann-Kendall test was used to determine significant historical trends in extreme indices, and the Spearman rank correlation (rho) to identify relationships between extreme indices and ACPs. For daily temperature indices, statistically significant (p<0.05) decreasing trends were found in ID (-0.40±0.34 days/year) and FD (-0.45±0.27 days/year) on a national scale of Finland during 1961-2011. The AO and EA/WR were most significant ACPs affecting variations in ID and FD, with rho = -0.73 and 0.42, respectively. For the daily precipitation extreme indices on the nation-wide of country over the study period (1961-2011), significant trends were only determined in SDII (0.01±0.00 mm/wet days year) and R95pTOT (0.19±0.09 %/year). Both of these indices (SDII and R95pTOT) showed the strongest correlations with the EA/WR pattern, with rho between from -0.42 to -0.34. The EA/WR pattern was also the most influential ACP for

  1. Temperature and modified atmosphere affect the quality of okra Temperatura e atmosfera modificada influenciam a qualidade do quiabo

    Directory of Open Access Journals (Sweden)

    Fernando Luiz Finger

    2008-01-01

    Full Text Available Little information is available on the influence of temperature on plastic films wrapped okra (Albelmoschus esculentus for their postharvested conservation. This works investigated the influence of the temperature and PVC film on the development of chilling injury and storability from one of the most popular Brazilian cultivar of okra cv. Amarelinho in fruits stored at 5, 10ºC and at 25ºC. Fruits were harvest at commercial maturity stage with length ranging from 8 to 12 cm, and immediately wrapped in PVC over a polystyrene tray and than stored until visible deterioration or wilting symptoms. Lowering the temperature of storage room from 25 to 10 or 5ºC decreased the weight loss in both PVC wrapped and control fruits, with a lower rate at 5ºC. By reducing the temperature to 5 or 10ºC and wrapping the fruits in PVC film, the relative water content of the fruit pericarp was maintained throughout the storage, while at 25ºC the high weight loss was associated with significant reduction of the water content. The development of chilling symptoms was delayed by the presence of PVC film in fruits stored at 5ºC. However, at 10ºC symptoms of pitting were not developed in PVC wrapped or control fruits up to tenth day of storage. The rate of chlorophyll degradation was diminished by reducing the temperature and by wrapping the fruits with PVC film. The appearance of severe chilling symptoms at 5ºC was associated to less chlorophyll in the fruit pericarp on the control as compared to their content in the PVC wrapped fruits.Para o armazenamento do quiabo (Albelmoschus esculentus há poucas informações disponíveis sobre a influência da temperatura e filmes plásticos na conservação pós-colheita desta hortaliça. Para investigar a influência da temperatura e do filme de PVC na qualidade e desenvolvimento de sintomas de injúria por frio de uma das mais populares cultivares brasileira de quiabo cv. Amarelinho, os frutos foram armazenados a 5, 10

  2. Scaling properties of velocity and temperature spectra above the surface friction layer in a convective atmospheric boundary layer

    Directory of Open Access Journals (Sweden)

    K. G. McNaughton

    2007-06-01

    Full Text Available We report velocity and temperature spectra measured at nine levels from 1.42 meters up to 25.7 m over a smooth playa in Western Utah. Data are from highly convective conditions when the magnitude of the Obukhov length (our proxy for the depth of the surface friction layer was less than 2 m. Our results are somewhat similar to the results reported from the Minnesota experiment of Kaimal et al. (1976, but show significant differences in detail. Our velocity spectra show no evidence of buoyant production of kinetic energy at at the scale of the thermal structures. We interpret our velocity spectra to be the result of outer eddies interacting with the ground, not "local free convection".

    We observe that velocity spectra represent the spectral distribution of the kinetic energy of the turbulence, so we use energy scales based on total turbulence energy in the convective boundary layer (CBL to collapse our spectra. For the horizontal velocity spectra this scale is (zi εo2/3, where zi is inversion height and εo is the dissipation rate in the bulk CBL. This scale functionally replaces the Deardorff convective velocity scale. Vertical motions are blocked by the ground, so the outer eddies most effective in creating vertical motions come from the inertial subrange of the outer turbulence. We deduce that the appropriate scale for the peak region of the vertical velocity spectra is (z εo2/3 where z is height above ground. Deviations from perfect spectral collapse under these scalings at large and small wavenumbers are explained in terms of the energy transport and the eddy structures of the flow.

    We find that the peaks of the temperature spectra collapse when wavenumbers are scaled using (z1/2 zi1/2. That is, the lengths of the thermal structures depend on both the lengths of the

  3. Industrial-age changes in atmospheric [CO2] and temperature differentially alter responses of faster- and slower-growing Eucalyptus seedlings to short-term drought.

    Science.gov (United States)

    Lewis, James D; Smith, Renee A; Ghannoum, Oula; Logan, Barry A; Phillips, Nathan G; Tissue, David T

    2013-05-01

    Climate change may alter forest composition by differentially affecting the responses of faster- and slower-growing tree species to drought. However, the combined effects of rising atmospheric CO2 concentration ([CO2]) and temperature on drought responses of trees are poorly understood. Here, we examined interactive effects of temperature (ambient, ambient + °C) and [CO2] (290, 400 and 650mu;l l(-1)) on drought responses of Eucalyptus saligna Sm. (faster-growing) and E. sideroxylon A. Cunn. ex Woolls (slower-growing) seedlings. Drought was imposed via a controlled reduction in soil water over 1-2 weeks, re-watering seedlings when leaves visibly wilted. In ambient temperature, the effect of drought on the light-saturated net photosynthetic rate (Asat) in E. saligna decreased as [CO2] increased from pre-industrial to future concentrations, but rising [CO2] did not affect the response in Eucalyptus sideroxylon. In contrast, elevated temperature exacerbated the effect of drought in reducing Asat in both species. The drought response of Asat reflected changes in stomatal conductance (gs) associated with species and treatment differences in (i) utilization of soil moisture and (ii) leaf area ratio (leaf area per unit plant dry mass). Across [CO2] and temperature treatments, E. saligna wilted at higher soil water potentials compared with E. sideroxylon. Photosynthetic recovery from drought was 90% complete 2 days following re-watering across all species and treatments. Our results suggest that E. saligna (faster-growing) seedlings are more susceptible to drought than E. sideroxylon (slower-growing) seedlings. The greater susceptibility to drought of E. saligna reflected faster drawdown of soil moisture, associated with more leaf area and leaf area ratio, and the ability of E. sideroxylon to maintain higher gs at a given soil moisture. Inclusion of a pre-industrial [CO2] treatment allowed us to conclude that susceptibility of these species to short-term drought

  4. Spatially resolved ozone densities and gas temperatures in a time modulated RF driven atmospheric pressure plasma jet: an analysis of the production and destruction mechanisms

    International Nuclear Information System (INIS)

    In this work, a time modulated RF driven DBD-like atmospheric pressure plasma jet in Ar + 2%O2, operating at a time averaged power of 6.5 W is investigated. Spatially resolved ozone densities and gas temperatures are obtained by UV absorption and Rayleigh scattering, respectively. Significant gas heating in the core of the plasma up to 700 K is found and at the position of this increased gas temperature a depletion of the ozone density is found. The production and destruction reactions of O3 in the jet effluent as a function of the distance from the nozzle are obtained from a zero-dimensional chemical kinetics model in plug flow mode which considers relevant air chemistry due to air entrainment in the jet fluent. A comparison of the measurements and the models show that the depletion of O3 in the core of the plasma is mainly caused by an enhanced destruction of O3 due to a large atomic oxygen density. (paper)

  5. An 80-year summer temperature history from the Xiao Dongkemadi ice core in the central Tibetan Plateau and its association with atmospheric circulation

    Science.gov (United States)

    Li, Xiangying; Ding, Yongjian; Yu, Zhongbo; Mika, Sillanpää; Liu, Shiyin; Shangguan, Donghui; Lu, Chengyang

    2015-02-01

    The climate significance of oxygen isotopes from the central Tibetan Plateau (cTP) ice cores is a debated issue because of large scale atmospheric circulation. A high-resolution δ18O record was recovered from the Xiao Dongkemadi (XD) ice core, which expanded the spatial coverage of δ18O data in this region. Annual average δ18O correlated significantly with nearby MJJAS air temperatures, suggesting the δ18O can be used as a proxy to reconstruct regional climate change. The reconstructed temperature anomaly is related to the regional and global warming trends, and the greater warming amplitude since 1970s is related to the elevation dependency of the warming signal. The close relationship of the warming to variations in glacier mass balances and discharge reveal that recent warming has led to obvious glacier shrinkage and runoff increase. Correlation analysis suggests that monsoon and westerly moisture substantially influence the cTP ice core records, along with an increase in their level of contribution to the XD core accumulation in recent decades, and confirms a teleconnection of regional climate of the cTP ice cores with climate parameters in the Indian and North Atlantic Oceans.

  6. Nonisothermal Pluto atmosphere models

    International Nuclear Information System (INIS)

    The present thermal profile calculation for a Pluto atmosphere model characterized by a high number fraction of CH4 molecules encompasses atmospheric heating by solar UV flux absorption and conductive transport cooling to the surface of Pluto. The stellar occultation curve predicted for an atmosphere of several-microbar surface pressures (which entail the existence of a substantial temperature gradient close to the surface) agrees with observations and implies that the normal and tangential optical depth of the atmosphere is almost negligible. The minimum period for atmospheric methane depletion is calculated to be 30 years. 29 refs

  7. Increased soil temperature and atmospheric N deposition have no effect on the N status and growth of a mature balsam fir forest

    Science.gov (United States)

    D'Orangeville, L.; Houle, D.; Côté, B.; Duchesne, L.; Morin, H.

    2013-07-01

    Nitrogen (N) is a major growth-limiting factor in boreal forest ecosystems. Increases of temperature and atmospheric N deposition are expected to affect forest growth directly and indirectly by increasing N availability due to higher rates of N mineralization. In order to understand the potential impacts of these changes, a mature balsam fir stand in Québec, Canada, was subjected during three consecutive growing seasons (2009-2011) to (i) experimentally increased soil temperature (4 °C) and earlier snowmelt (2-3 weeks) as well as (ii) increased inorganic N concentration in artificial precipitation (3 × current N concentrations using 15NH4-15NO3). Soil inorganic N was measured using buried ion-exchange membranes (PRS™ probes) and standard soil extractions. Dendrometers were used to monitor the variations in diameter growth and needles were analyzed annually for N to assess the nutritional response of trees. Results from the second (2010) and third (2011) year of treatment are reported. After three years of treatment, there was no significant increase in soil nitrate (NO3) or ammonium (NH4) availability either in the organic or in the mineral soil as measured with standard soil extractions. Similar results were obtained with ion-exchange membranes, except for NH4 in the forest floor, which increased by an average of 54% over the two years. No effect of treatments were observed on needle N or diameter growth, but an 8-day earlier peak in diameter growth was measured in heated plots in 2010. We attributed the limited effects of our treatments to the acute soil competition for available N at the site. As a result, the projected modifications of the forest N cycle and concomitant increased forest growth due to an earlier snowmelt, increased soil temperature and N deposition should be considered with caution in similar cold N-poor ecosystems.

  8. Three years of increased soil temperature and atmospheric N deposition have no effect on the N status and growth of a mature balsam fir forest

    Science.gov (United States)

    D'Orangeville, L.; Houle, D.; Côté, B.; Duchesne, L.; Morin, H.

    2013-01-01

    Nitrogen (N) is a major growth-limiting factor in boreal forest ecosystems. Increases of temperature and atmospheric N deposition are expected to affect forest growth directly and indirectly, by increasing N availability due to higher rates of N mineralization. In order to understand the potential impacts of these changes, a mature balsam fir stand in Québec, Canada, was subjected to (i) experimentally increased soil temperature (4 °C) and earlier snowmelt (2-3 weeks) as well as (ii) increased inorganic N concentration in artificial precipitation (3 × current N concentrations using 15NH4-15NO3). Soil inorganic N was measured using buried ion exchange membranes (PRS™-probes) and standard soil extractions. Dendrometers were used to monitor the variations in diameter growth and needles were analyzed annually for N to assess the nutritional response of trees. After three years of treatment, there was no significant increase in soil nitrate (NO3) or ammonium (NH4) availability either in the organic or in the mineral soil as measured with standard soil extractions. Similar results were obtained with ion exchange membranes, except for an average 54% increase in the forest floor available NH4. No effect of treatments were observed on needle N or diameter growth, but an eight-day earlier peak in diameter growth was measured in heated plots in 2010. We attributed the limited effects of our treatments to the acute soil competition for available N at the site. As a result, the projected modifications of the forest N cycle and concomitant increased forest growth due to an earlier snowmelt, increased soil temperature and N deposition should be considered with caution in similar cold N-poor ecosystems.

  9. Three years of increased soil temperature and atmospheric N deposition have no effect on the N status and growth of a mature balsam fir forest

    Directory of Open Access Journals (Sweden)

    L. D'Orangeville

    2013-01-01

    Full Text Available Nitrogen (N is a major growth-limiting factor in boreal forest ecosystems. Increases of temperature and atmospheric N deposition are expected to affect forest growth directly and indirectly, by increasing N availability due to higher rates of N mineralization. In order to understand the potential impacts of these changes, a mature balsam fir stand in Québec, Canada, was subjected to (i experimentally increased soil temperature (4 °C and earlier snowmelt (2–3 weeks as well as (ii increased inorganic N concentration in artificial precipitation (3 × current N concentrations using 15NH415NO3. Soil inorganic N was measured using buried ion exchange membranes (PRS™-probes and standard soil extractions. Dendrometers were used to monitor the variations in diameter growth and needles were analyzed annually for N to assess the nutritional response of trees.

    After three years of treatment, there was no significant increase in soil nitrate (NO3 or ammonium (NH4 availability either in the organic or in the mineral soil as measured with standard soil extractions. Similar results were obtained with ion exchange membranes, except for an average 54% increase in the forest floor available NH4. No effect of treatments were observed on needle N or diameter growth, but an eight-day earlier peak in diameter growth was measured in heated plots in 2010.

    We attributed the limited effects of our treatments to the acute soil competition for available N at the site. As a result, the projected modifications of the forest N cycle and concomitant increased forest growth due to an earlier snowmelt, increased soil temperature and N deposition should be considered with caution in similar cold N-poor ecosystems.

  10. Increased soil temperature and atmospheric N deposition have no effect on the N status and growth of a mature balsam fir forest

    Directory of Open Access Journals (Sweden)

    L. D'Orangeville

    2013-07-01

    Full Text Available Nitrogen (N is a major growth-limiting factor in boreal forest ecosystems. Increases of temperature and atmospheric N deposition are expected to affect forest growth directly and indirectly by increasing N availability due to higher rates of N mineralization. In order to understand the potential impacts of these changes, a mature balsam fir stand in Québec, Canada, was subjected during three consecutive growing seasons (2009–2011 to (i experimentally increased soil temperature (4 °C and earlier snowmelt (2–3 weeks as well as (ii increased inorganic N concentration in artificial precipitation (3 × current N concentrations using 15NH4-15NO3. Soil inorganic N was measured using buried ion-exchange membranes (PRS™ probes and standard soil extractions. Dendrometers were used to monitor the variations in diameter growth and needles were analyzed annually for N to assess the nutritional response of trees. Results from the second (2010 and third (2011 year of treatment are reported. After three years of treatment, there was no significant increase in soil nitrate (NO3 or ammonium (NH4 availability either in the organic or in the mineral soil as measured with standard soil extractions. Similar results were obtained with ion-exchange membranes, except for NH4 in the forest floor, which increased by an average of 54% over the two years. No effect of treatments were observed on needle N or diameter growth, but an 8-day earlier peak in diameter growth was measured in heated plots in 2010. We attributed the limited effects of our treatments to the acute soil competition for available N at the site. As a result, the projected modifications of the forest N cycle and concomitant increased forest growth due to an earlier snowmelt, increased soil temperature and N deposition should be considered with caution in similar cold N-poor ecosystems.

  11. Are microbial N transformation rates in a permanent grassland soil after 17 years of elevated atmospheric CO2 sensitive to soil temperature?

    Science.gov (United States)

    Moser, Gerald; Gorenflo, André; Brenzinger, Kristof; Clough, Tim; Braker, Gesche; Müller, Christoph

    2016-04-01

    Long-term observations (17 years) within the Giessen Free Air Carbon dioxide Enrichment (Giessen FACE) study on permanent grassland showed that the carbon fertilization caused significant changes in the ecosystem nitrogen cycle. These changes are responsible for a doubling of annual N2O emissions under elevated atmospheric CO2 (eCO2) caused by increased emissions during the plant growing season. The goal of this lab study was to understand how soil temperature influences the long-term effects of eCO2 and plant carbon input on microbial N transformations in the Giessen FACE. Therefore, a pulse labelling study with 15N tracing of 15NH4+ and 15NO3- was carried out with incubated soil samples from elevated and ambient CO2 FACE rings in climate chambers at two different temperatures (10°C and 19°C), while water filled pore space of the samples was adjusted to the same level. The various N pools in the soil (NH4+, NO3-, NO2-, soil organic matter), N2O emissions and simultaneous gross N transformation rates were quantified. The quantification of the gross N transformations are based on the turnover of 15NH4+, 15NO3-, 15NO2- and shall illuminate the interaction between carbon fertilization, temperature and changes in nitrogen cycle in this grassland soil. While the soil respiration after labelling was significantly increased at 19°C compared to 10°C, N2O emissions showed no significant differences. There were also no significant differences of N2O emissions between soil samples from control and elevated CO2 rings within each temperature level. As the soil temperature (within the range of 10-19°C) had no significant effects on N transformations responsible for the observed doubling of N2O emissions under eCO2, it seems most likely that other factors like direct carbon input by plants and/or soil moisture differences between ambient and elevated rings in the field are responsible for the observed increase in N2O emissions under eCO2.

  12. Spatial and temporal variation of phthalic acid esters (PAEs) in atmospheric PM10 and PM2.5 and the influence of ambient temperature in Tianjin, China

    Science.gov (United States)

    Kong, Shaofei; Ji, Yaqin; Liu, Lingling; Chen, Li; Zhao, Xueyan; Wang, Jiajun; Bai, Zhipeng; Sun, Zengrong

    2013-08-01

    Phthalic acid esters (PAEs) are produced in large amounts throughout the world and are excessively used in various industries, which have posed a serious threat to human health and the environment. An investigation of six major PAEs congeners in atmospheric PM10 and PM2.5 was synchronously conducted at seven sites belonging to different functional zones in spring, summer and winter in Tianjin, China in 2010. Results showed that the average concentrations of DMP, DEP, DBP, BBP, DEHP and DOP in PM10 were 0.88, 0.73, 12.90, 0.15, 98.29 and 0.83 ng m-3, respectively, and in PM2.5, they were 0.54, 0.30, 8.72, 0.08, 75.68 and 0.33 ng m-3, respectively. DEHP and DBP were the predominant species. The industrial site exhibited highest PAEs values as 135.9 ± 202.8 ng m-3. In winter, the detected percentages for DOP were low. The other five PAEs concentrations were higher in winter than those in spring and summer, which may be related to the influence of emission sources, meteorological parameters and the chemical-physical characteristic of themselves. Except for DOP, other PAEs were negatively correlated with ambient temperature and the relationships were the best fitted as exponential forms. Significant positive correlations were found for PAEs in PM2.5 and PM10, indicating common sources. The PM2.5/PM10 ratios (0.53-0.70) for the six PAEs concentrations suggested that they were preferentially concentrated in finer particles. Principal component analysis indicated the emission from cosmetics and personal care products, plasticizers and sewage and industrial wastewater may be important sources for PAEs in atmospheric particulate matter in Tianjin.

  13. Chemical characterisation of atmospheric aerosols during a 2007 summer field campaign at Brasschaat, Belgium: sources and source processes, time series, diel variations, and temperature dependencies

    Directory of Open Access Journals (Sweden)

    Y. Gómez-González

    2011-08-01

    Full Text Available Measurements of organic marker compounds and inorganic species were performed on PM2.5 aerosols from a Belgian forest site that is severely impacted by urban pollution ("De Inslag", Brasschaat, Belgium during a 2007 summer period within the framework of the "Formation mechanisms, marker compounds, and source apportionment for biogenic atmospheric aerosols (BIOSOL" project. The objectives of this study were to determine sources, source processes, time series, and diel variations of the organic species, and to explore the relationships between their concentrations and those of trace gases (O3, NO2, SO2, and CO2 or meteorological parameters (temperature, relative humidity, wind speed, and rain fall. The measured organic species included (i low-molecular weight (MW dicarboxylic acids (LMW DCAs, (ii methanesulfonate (MSA, and (iii terpenoic acids originating from the oxidation of α-pinene, β-pinene, d-limonene and Δ3-carene, and (iv organosulfates related to secondary organic aerosol (SOA from the oxidation of isoprene and α-pinene. The measurements of MSA, the LMW DCAs and selected inorganic species were done with ion chromatography (IC, while those of the terpenoic acids and organosulfates were performed using liquid chromatography with negative ion electrospray ionisation mass spectrometry [LC/(−ESI-MS]. The organic tracers explained, on average, 5.3 % of the organic carbon (OC, of which 0.7 % was due to MSA, 3.4 % to LMW DCAs, and 1.2 % to organosulfates and terpenoic acids. The highest atmospheric concentrations of most species were observed during the first five days of the campaign, which were characterised by maximum day-time temperatures >22 °C. Most of the terpenoic acids and the organosulfates peaked during day-time, consistent with their photochemical origin, except the MW 295 α-pinene-related nitrooxy organosulfates and the terpenoic acids,

  14. Pluto's atmosphere near perihelion

    International Nuclear Information System (INIS)

    A recent stellar occultation has confirmed predictions that Pluto has an atmosphere which is sufficiently thick to uniformly envelope the planet and to extend far above the surface. Pluto's atmosphere consists of methane and perhaps other volatile gases at temperatures below their freezing points; it should regulate the surface temperature of its volatile ices to a globally uniform value. As Pluto approaches and passes through perihelion, a seasonal maximum in the atmospheric bulk and a corresponding minimum in the exposed volatile ice abundance is expected to occur. The lag in maximum atmospheric bulk relative to perihelion will be diagnostic of the surface thermal properties. An estimate of Pluto's atmospheric bulk may result if a global darkening (resulting from the disappearance of the seasonally deposited frosts) occurs before the time of maximum atmospheric bulk. The ice deposited shortly after perihelion may be diagnostic of the composition of Pluto's volatile reservoir

  15. Low temperature rate coefficients for the reactions of 1CH2 with reactive and non-reactive species, and the implications for Titan's atmosphere

    Science.gov (United States)

    Douglas, Kevin; Slater, Eloise; Blitz, Mark; Plane, John; Heard, Dwayne; Seakins, Paul

    2016-04-01

    The Cassini-Huygens mission to Titan revealed unexpectedly large amounts of benzene in the troposphere, and confirmed the absence of a global ethane ocean as predicted by photochemical models of methane conversion over the lifetime of the solar system. An important chemical intermediate in both the production and loss of benzene and ethane is the first electronically excited state of methylene, 1CH2. For example, at room temperature an important reaction of 1CH2 is with acetylene (R1a), leading to the formation of propargyl (C3H3)[1]. The subsequent recombination of propargyl radicals is the major suggested route to benzene in Titan's atmosphere (R2)[2]. In addition to reaction of 1CH2 leading to products, there is also competition between inelastic electronic relaxation to form the ground triplet state 3CH2 (R1b). This ground state 3CH2 has a markedly different reactivity to the singlet, reacting primarily with methyl radicals (CH3) to form ethene (R3). As methyl radical recombination is the primary route to ethane (R4)[3], reactions of 1CH2 will also heavily influence the ethane budget on Titan. 1CH2 + C2H2 → C3H3 + H (R1a) 1CH2 + C2H2 → 3CH2 + C2H2 (R1b) C3H3 + C3H3 → C6H6 (R2) 3CH2 + CH3 → C2H4 + H (R3) CH3 + CH3 (+ M) → C2H6 (R4) Thus this competition between chemical reaction and electronic relaxation in the reactions of 1CH2 with H2, CH4, C2H4, and C2H6 will play an important role in determining the benzene and ethane budgets on Titan. Despite this there are no measurements of any rate constants for 1CH2 at temperatures relevant to Titan's atmosphere (60 - 170 K). Using a pulsed Laval nozzle apparatus coupled with pulsed laser photolysis laser-induced fluorescence, the low temperature reaction kinetics for the removal of 1CH2 with nitrogen, hydrogen, methane, ethane, ethene, acetylene, and oxygen, have been studied. The results revealed an increase in the removal rate of 1CH2 at temperatures below 200 K, with a sharp increase of around a factor of

  16. Solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon, and carbon monoxide in 1-butyl-3-methylimidazolium tetrafluoroborate between temperatures 283 K and 343 K and at pressures close to atmospheric

    OpenAIRE

    Jacquemin, J.; Costa Gomes, M.F.; Husson, P.; Majer, V.

    2006-01-01

    Experimental values for the solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon and carbon monoxide in 1-butyl-3- methylimidazolium tetrafluoroborate, [bmim][BF4] - a room temperature ionic liquid - are reported as a function of temperature between 283 K and 343 K and at pressures close to atmospheric. Carbon dioxide is the most soluble gas with mole fraction solubilities of the order of 10-2. Ethane and methane are one order of magnitude more soluble than the oth...

  17. Temperature- and pH-dependent aqueous-phase kinetics of the reactions of glyoxal and methylglyoxal with atmospheric amines and ammonium sulfate

    Science.gov (United States)

    Sedehi, Nahzaneen; Takano, Hiromi; Blasic, Vanessa A.; Sullivan, Kristin A.; De Haan, David O.

    2013-10-01

    Reactions of glyoxal (Glx) and methylglyoxal (MG) with primary amines and ammonium salts may produce brown carbon and N-containing oligomers in aqueous aerosol. 1H NMR monitoring of reactant losses and product appearance in bulk aqueous reactions were used to derive rate constants and quantify competing reaction pathways as a function of pH and temperature. Glx + ammonium sulfate (AS) and amine reactions generate products containing C-N bonds, with rates depending directly on pH: rate = (70 ± 60) M-1 s-1fAld [Glx]totfAm [Am]tot, where fAld is the fraction of aldehyde with a dehydrated aldehyde functional group, and fAm is the fraction of amine or ammonia that is deprotonated at a given pH. MG + amine reactions generate mostly aldol condensation products and exhibit less pH dependence: rate = 10[(0.36 ± 0.06) × pH - (3.6 ± 0.3)] M-1 s-1fAld [MG]tot [Am]tot. Aldehyde + AS reactions are less temperature-dependent (Ea = 18 ± 8 kJ mol-1) than corresponding amine reactions (Ea = 50 ± 11 kJ mol-1). Using aerosol concentrations of [OH] = 10-12 M, [amine]tot = [AS] = 0.1 M, fGlx = 0.046 and fMG = 0.09, we estimate that OH radical reactions are normally the major aerosol-phase sink for both dicarbonyl compounds. However, reactions with AS and amines together can account for up to 12 and 45% of daytime aerosol-phase glyoxal and methylglyoxal reactivity, respectively, in marine aerosol at pH 5.5. Reactions with AS and amines become less important in acidic or non-marine aerosol, but may still be significant atmospheric sources of brown carbon, imidazoles, and nitrogen-containing oligomers.

  18. Effect of modified atmosphere and temperature abuse on the growth from spores and cereulide production of Bacillus weihenstephanensis in a cooked chilled meat sausage.

    Science.gov (United States)

    Thorsen, Line; Budde, Birgitte Bjørn; Koch, Anette Granly; Klingberg, Trine Danø

    2009-04-15

    The effect of modified atmosphere packaging (MAP) on the germination and growth of toxin producing psychrotolerant Bacillus spp is not well described. A model agar system mimicking a cooked meat product was used in initial experiments. Incubation at refrigeration temperature of 8 degrees C for 5 weeks of 26 Bacillus weihenstephanensis including two emetic toxin (cereulide) producing strains showed that B. weihenstephanensis is sensitive to MAP containing CO2. The sensitivity to 20% CO2 was dependent on strain and oxygen level, being increased when oxygen was excluded from the MAP. Growth from spores was observed at the earliest within 2 weeks when 20% CO2 was combined with 2% O2 and in 3 weeks when combined with "0"% O2 (the remaining atmosphere was made up from N2). Results were validated in a cooked meat sausage model for two non-emetic and one emetic B. weihenstephanensis strain. The packaging film oxygen transfer rates (OTR) were 1.3 and 40 ml/m(2)/24 h and the atmospheres were 2% O2/20% CO2 and "0"% O2/20% CO2. Oxygen availability had a large impact on the growth from spores in the MAP meat sausage, only the most oxygen restricted condition (OTR of 1.3 ml/m(2)/24 h and "0"% O2/20 % CO2 inhibited growth of the three strains during 4 weeks storage at 8 degrees C. Cereulide production was undetectable during storage at 8 degrees C irrespective of choice of the MAP (quantified by liquid chromatography mass spectrometry/mass spectrometry). MAP storage at 8 degrees C for 1 and 3 weeks followed by opening of packages and temperature abuse for 1.5 h daily at 20 degrees C during 1 week resulted in increased cell counts and variable cereulide production in the meat sausage. A pre-history at 8 degrees C for 1 week in MAP with OTR of 1.3 or 40 ml/m(2)/24 h and 2% O2 resulted in cereulide concentrations of 0.816-1.353 microg/g meat sausage, while a pre-history under the most oxygen restricted condition (OTR of 1.3 ml/m(2)/24 h, "0"% O2/20 % CO2 resulted in minimal

  19. Laser-induced Fluorescence and Optical Emission Spectroscopy for the Determination of Reactive Species in the Effluent of Atmospheric Pressure Low Temperature Plasma Jets

    Science.gov (United States)

    Pei, Xuekai; Razavi, Hamid; Lu, Xinpei; Laroussi, Mounir

    2014-10-01

    OH radicals and O atoms are important active species in various applications of room temperature atmospheric pressure plasma jet (RT-APPJ). So the determination of absolute density of OH radicals and O atoms in RT-APPJs is necessary. In this work, the time and spatially resolved OH radicals density of a RT-APPJ are measured using the laser-induced fluorescence (LIF) technology. In addition, the spatial distribution of the emitting species along the axial direction of the jet is of interest and is measured using optical emission spectroscopy. The absolute OH density of the RT-APPJ is about 2.0 × 1013 cm-3 at 5 mm away from the plasma jet nozzle and 1 μs after the discharge. The OH density reaches a maximum when H2O concentration in helium gas flow is about 130ppm. In order to control the OH density, the effect of voltage polarity, applied voltage magnitude, pulse frequency, pulse width on the OH density are also investigated and discussed. O atoms are investigated by TA-LIF. It is demonstrated that the O atoms density reaches a maximum when O2 percent is about 0.3% in pure He and the lifetime of O atoms in RT-APPJ is much longer (up to dozens of ms) than OH radicals.

  20. Reconstructing sea surface temperature, sea surface salinity and partial pressure of carbon dioxide in atmosphere in the Okinawa Trough during the Holocene and their paleoclimatic implications

    Institute of Scientific and Technical Information of China (English)

    MENGXianwei; LIUYanguang; LlUZhenxia; DUDewen; HUANGQiyu; Y.Saito

    2003-01-01

    The sediment core DGKS9603 collected from the Okinawa Trough was used as research target. By use of unsaturated index U37k of long-chain alkenone, δ13C of POC and of planktonic foraminifera (G sacculifer), the evolutions of sea surface temperature and partial pressure of carbon dioxide in the atmosphere during the Holocene were reconstructed in the Okinawa Trough. And in combination of δ18O of planktonic foraminifera, the relative difference of sea surface salinity during the Holocene was also reconstructed.Consequently, three cooling events (E1-E3) were identified,each of which occurred at 1.7-1.6, 5.1-4.8 and 8.1-7.4kaBP (cal), respectively. Of the three events, E2 and E3 are globally comparable, their occurrence mechanism would be that the main stream of the Kuroshio Current shifted eastward due to the enhanced circulation of the northeastern Pacific Ocean, which was driven in turn by amplified intensity of sunshine and subsequent enhancement of subtropical high pressure; E1 corresponds to the Small Ice-Age Event occurring between 1550 and 1850AD in China. In the Okinawa Trough, E1 might be also related to the eastward shift of main stream of the Kuroshio current driven by powerful Asia winter monsoon.

  1. Generation and loss of reactive oxygen species in low-temperature atmospheric-pressure RF He + O2 + H2O plasmas

    International Nuclear Information System (INIS)

    This study focuses on the generation and loss of reactive oxygen species (ROS) in low-temperature atmospheric-pressure RF (13.56 MHz) He + O2 + H2O plasmas, which are of interest for many biomedical applications. These plasmas create cocktails of ROS containing ozone, singlet oxygen, atomic oxygen, hydroxyl radicals, hydrogen peroxide and hydroperoxyl radicals, i.e. ROS of great significance as recognized by the free-radical biology community. By means of one-dimensional fluid simulations (61 species, 878 reactions), the key ROS and their generation and loss mechanisms are identified as a function of the oxygen and water content in the feed gas. Identification of the main chemical pathways can guide the optimization of He + O2 + H2O plasmas for the production of particular ROS. It is found that for a given oxygen concentration, the presence of water in the feed gas decreases the net production of oxygen-derived ROS, while for a given water concentration, the presence of oxygen enhances the net production of water-derived ROS. Although most ROS can be generated in a wide range of oxygen and water admixtures, the chemical pathways leading to their generation change significantly as a function of the feed gas composition. Therefore, care must be taken when selecting reduced chemical sets to study these plasmas. (fast track communication)

  2. EO-based lake-ice cover and surface temperature products: Advancing process understanding and modeling capabilities of lake-atmosphere interactions in cold regions

    Science.gov (United States)

    Duguay, C. R.; Kheyrollah Pour, H.; Ochilov, S.

    2011-12-01

    Our ability to determine the energy and water budgets of lakes is critical to modeling high latitude weather and climate. In recent years, the proper representation of lake processes in numerical weather prediction (NWP) and regional climate (RCM) models has become a topic of much interest by the scientific community. With the increased resolution of the NWP models and RCMs, it has now become possible and necessary to improve the representation of lake-atmosphere interactions to better describe the energy exchange between the atmosphere and the lake surface. Among other lake properties, knowledge about lake surface temperature and ice-coverage is critical. These two parameters can either be obtained from observations or through simulations. Although much progress is being made with lake models, as implemented in NWP/RCM models, the assimilation of data on lake temperature and fractional ice coverage has been identified as highly desirable. Spatially and temporally consistent lake ice and lake surface temperature (LST) products are invaluable in this respect. These can be derived from Earth Observation (EO) systems. However, satellite-based products must be compared with existing lake models, as well as validated and further improved as needed, to generate lake ice and LST products for operational use by the modeling community. The European Space Agency (ESA) is supporting the international efforts coordinated by the Climate and Cryosphere (CliC) project of the World Climate Research Programme (WCRP) to exploit the use of EO technology, models and in situ data to improve the characterization of river and lake ice processes and their contribution to the Northern Hydrology system. The ESA-sponsored North Hydrology project aims to develop a portfolio of novel multi-mission geo-information products, maximizing the use of ESA satellite data, to respond to the scientific requirements of the CliC community and the operational requirements of the weather and climate

  3. Anomalous equivalent potential temperature: an atmospheric feature predicting days with higher risk for fatal outcome in acute ischemic stroke-a preliminary study.

    Science.gov (United States)

    Folyovich, András; Biczó, Dávid; Al-Muhanna, Nadim; Béres-Molnár, Anna K; Fejős, Ádám; Pintér, Ádám; Bereczki, Dániel; Fischer, Antal; Vadasdi, Károly; Pintér, Ferenc

    2015-09-01

    Acute stroke is a life-threatening condition. Fatal outcome is related to risk factors, some of these affected by climatic changes. Forecasting potentially harmful atmospheric processes may therefore be of practical importance in the acute care of stroke patients. We analyzed the history of all patients with acute ischemic stroke (N = 184) confirmed by neuroimaging including those who died (N = 35, 15 males) at our hospital department in the winter months of 2009. Patient data were anonymized, and the human meteorologists were only aware of patients' age, gender, and exact time of death. Of the meteorological parameters, equivalent potential temperature (EPT) has been chosen for analysis. EPT is generally used for forecasting thunderstorms, but in the case of synoptic scale airflow (10(6) m), it is suitable for characterizing the air mass inflowing from different regions. The behavior of measured EPT values was compared to the climatic (30 years) averages. We developed meteorological criteria for anomalous periods of EPT and tested if such periods are associated with higher rate of fatal outcome. The duration of anomalous and non-anomalous periods was nearly equal during the studied 3 months. Stroke onset distributed similarly between anomalous and non-anomalous days; however, of the 35 deaths, 27 occurred during anomalous periods: on average, 0.56 deaths occurred on anomalous days and 0.19 on non-anomalous days. Winter periods meeting the criteria of anomalous EPT may have a significant adverse human-meteorological impact on the outcome in acute ischemic stroke. PMID:26233665

  4. Occurrence of gaseous and particulate polycyclic aromatic hydrocarbons in the urban atmosphere: study of sources and ambient temperature effect on the gas/particle concentration and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Tsapakis, Manolis [Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, EL-71409 Heraklion (Greece); Stephanou, Euripides G. [Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, EL-71409 Heraklion (Greece)]. E-mail: stephanou@chemistry.uoc.gr

    2005-01-01

    The presence of polycyclic aromatic hydrocarbons (PAHs) in an urban region (Heraklion, Greece) and processes that govern their atmospheric fate were studied from November 2000 until February 2002. Sixteen samples were collected, by using an artifact-free sampling device, on a monthly basis and the concentration of PAHs in gas and particulate phase was determined. The most abundant members (gas + particles) were phenanthrene (20.0 {+-} 7.0 ng m{sup -3}), fluoranthene (6.5 {+-} 1.7 ng m{sup -3}), pyrene (6.6 {+-} 2.4 ng m{sup -3}), and chrysene (3.1 {+-} 1.5 ng m{sup -3}). Total concentration (gas + particulate) of PAH ranged from 44.3 to 129.2 ng m{sup -3}, with a mean concentration of 79.3 ng m{sup -3}. Total concentration of PAHs in gas phase ranged from 31.4 to 84.7 ng m{sup -3} with non-observable seasonal variation. Conversely, maximum PAH concentrations in the particulate phase occurred during winter months. Particulate concentration varied from 11.4 to 44.9 ng m{sup -3}, with an average of 25.2 ng m{sup -3}. PAH distribution between gas and particulate phase was in agreement with the sub-cooled vapor pressure. Shift in gas/particle distribution due to difference in ambient temperature elucidated to some extent the seasonal variation of the concentration of PAHs in particles. - Capsule: Ambient PAH partitioning between gas and particle phases vary between compounds and with environmental conditions.

  5. Impact of storm-induced cooling of sea surface temperature on large turbulent eddies and vertical turbulent transport in the atmospheric boundary layer of Hurricane Isaac

    Science.gov (United States)

    Zhu, Ping; Wang, Yuting; Chen, Shuyi S.; Curcic, Milan; Gao, Cen

    2016-01-01

    Roll vortices in the atmospheric boundary layer (ABL) are important to oil operation and oil spill transport. This study investigates the impact of storm-induced sea surface temperature (SST) cooling on the roll vortices generated by the convective and dynamic instability in the ABL of Hurricane Isaac (2012) and the roll induced transport using hindcasting large eddy simulations (LESs) configured from the multiply nested Weather Research & Forecasting model. Two experiments are performed: one forced by the Unified Wave INterface - Coupled Model and the other with the SST replaced by the NCEP FNL analysis that does not include the storm-induced SST cooling. The simulations show that the roll vortices are the prevalent eddy circulations in the ABL of Isaac. The storm-induced SST cooling causes the ABL stability falls in a range that satisfies the empirical criterion of roll generation by dynamic instability, whereas the ABL stability without considering the storm-induced SST cooling meets the criterion of roll generation by convective instability. The ABL roll is skewed and the increase of convective instability enhances the skewness. Large convective instability leads to large vertical transport of heat and moisture; whereas the dominant dynamic instability results in large turbulent kinetic energy but relatively weak heat and moisture transport. This study suggests that failure to consider roll vortices or incorrect initiation of dynamic and convective instability of rolls in simulations may substantially affect the transport of momentum, energy, and pollutants in the ABL and the dispersion/advection of oil spill fume at the ocean surface.

  6. Synergy of CuO and CeO2 combination for mercury oxidation under low-temperature selective catalytic reduction atmosphere

    KAUST Repository

    Li, Hailong

    2016-07-19

    Synergy for low temperature Hg0 oxidation under selective catalytic reduction (SCR) atmosphere was achieved when copper oxides and cerium oxides were combined in a CuO-CeO2/TiO2 (CuCeTi) catalyst. Hg0 oxidation efficiency as high as 99.0% was observed on the CuCeTi catalyst at 200 °C, even the gas hourly space velocity was extremely high. To analyze the synergistic effect, comparisons of catalyst performance in the presence of different SCR reaction gases were systematically conducted over CuO/TiO2 (CuTi), CeO2/TiO2 (CeTi) and CuCeTi catalysts prepared by sol-gel method. The interactions between copper oxides and cerium oxides in CuCeTi catalyst yielded more surface chemisorbed oxygen, and facilitated the conversion of gas-phase O2 to surface oxygen, which are favorable for Hg0 oxidation. Copper oxides in the combination interacted with NO forming more chemisorbed oxygen for Hg0 oxidation in the absence of gas-phase O2. Cerium oxides in the combination promoted Hg0 oxidation through enhancing the transformations of NO to NO2. In the absence of NO, NH3 exhibited no inhibitive effect on Hg0 oxidation, because enough Lewis acid sites due to the combination of copper oxides and cerium oxides scavenged the competitive adsorption between NH3 and Hg0. In the presence of NO, although NH3 lowered Hg0 oxidation rate through inducing reduction of oxidized mercury, complete recovery of Hg0 oxidation activity over the CuCeTi catalyst was quickly achieved after cutting off NH3. This study revealed the synergistic effect of the combination of copper oxides and cerium oxides on Hg0 oxidation, and explored the involved mechanisms. Such knowledge would help obtaining maximum Hg0 oxidation co-benefit from SCR units in coal-fired power plants.

  7. Qualidade de ameixas 'Laetitia' em função da temperatura e da atmosfera de armazenamento Quality of 'Laetitia' plums as affected by temperature and storage atmosphere

    Directory of Open Access Journals (Sweden)

    Erlani de Oliveira Alves

    2010-12-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da temperatura e de atmosferas de armazenamento sobre a manutenção da qualidade de ameixas 'Laetitia'. Os tratamentos avaliados constituíram-se na combinação de duas temperaturas (-0,5ºC e 0,5ºC, com três atmosferas de armazenamento: armazenamento refrigerado (AR, com 21,0 kPa de O2 + 0,03 kPa de CO2; atmosfera controlada (AC, com 1,0 kPa de O2 + 3,0 kPa de CO2; e AC, com 2,0 kPa de O2 + 5,0 kPa de CO2. Após 60 dias de armazenamento, foram avaliadas: taxas respiratória e de produção de etileno, acidez titulável (AT, firmeza de polpa, atributos de textura, índice de cor vermelha e ângulo 'hue' (hº da casca, e incidência de rachaduras, podridões e degenerescência da polpa. O armazenamento refrigerado a -0,5ºC resultou em menores valores para o índice de cor vermelha, taxa respiratória e de produção de etileno e incidência de frutos rachados. Em ambas as condições de AC, a temperatura de 0,5ºC resultou em menor índice de cor vermelha, cor da epiderme mais verde, maior firmeza de polpa e menor taxa de produção de etileno, tanto na abertura da câmara como após quatro dias em condição ambiente. As condições de AC retardaram o amadurecimento dos frutos e reduziram a incidência de degenerescência de polpa. O armazenamento em AC, com 2,0 kPa de O2 + 5,0 kPa de CO2, a 0,5ºC, proporcionou menor taxa respiratória e menor incidência de podridões na saída da câmara, mas maior AT e força para penetração da polpa, após quatro dias em condição ambiente. No entanto, o armazenamento da ameixa 'Laetitia', nas condições de AC avaliadas, por um período de 60 dias, não reduziu a incidência de degenerescência da polpa.The aim of this work was to evaluate the effect of temperature and storage atmospheres on the quality of 'Laetitia' plums. The treatments were obtained from the combination of two temperatures (-0.5ºC and 0.5ºC with three storage atmospheres: cold

  8. Measurement of the Temperature Dependence of Line Mixing and Pressure Broadening Parameters between 296 and 90 K in the v3 band of 12CH4 and their Influence on Atmospheric Methane Retrievals

    Science.gov (United States)

    Mondelain, Didier; Payan, Sebastien; Deng, Wenping; Camy-Peyret, Claude; Hurtmans, Daniel; Mantz, Arlan W.

    2007-01-01

    We measured the temperature dependence of the nitrogen broadening, narrowing and line-mixing coefficients of four lines of the P9 manifold in the v3 band of 12CH4 for atmospheric purposes. The data were collected using our tunable diode laser (TDL) spectrometer with active wavenumber control coupled to a newly developed cold Herriott cell with a path length of 5.37 m and a temperature uniformity of better than 0.01 K along the cell. We recorded and analyzed spectra recorded at sample temperature between 90 K and room temperature. We have investigate the influence of our new results in the inversion model used to retrieve methane profiles from atmospheric spectra; our new results make it possible to retrieve significantly more precise methane profiles. The atmospheric spectra we utilized were obtained by several of us with a balloon-born Fourier Transform infrared experiment in a limb configuration. Differences up to 7% on the retrieved volume mixing ratio were found compared to an inversion model using only HITRAN04 spectroscopic parameters.

  9. Effective mie-scattering and CO2 absorption in the dust-laden Martian atmosphere and its impact on radiative-convective temperature changes in the lower scale heights

    Science.gov (United States)

    Pallmann, A. J.

    1976-01-01

    A time dependent computer model of radiative-convective-conductive heat transfer in the Martian ground-atmosphere system was refined by incorporating an intermediate line strength CO2 band absorption which together with the strong-and weak-line approximation closely simulated the radiative transmission through a vertically inhomogeneous stratification. About 33,000 CO2 lines were processed to cover the spectral range of solar and planetary radiation. Absorption by silicate dust particulates, was taken into consideration to study its impact on the ground-atmosphere temperature field as a function of time. This model was subsequently attuned to IRIS, IR-radiometric and S-band occultation data. Satisfactory simulations of the measured IRIS spectra were accomplished for the dust-free condition. In the case of variable dust loads, the simulations were sufficiently fair so that some inferences into the effect of dust on temperature were justified.

  10. The atmospheric chemistry of the warm Neptune GJ 3470b: influence of metallicity and temperature on the CH4/CO ratio

    CERN Document Server

    Venot, Olivia; Selsis, Franck; Tessenyi, Marcell; Iro, Nicolas

    2013-01-01

    Current observation techniques are able to probe the atmosphere of some giant exoplanets and get some clues about their atmospheric composition. However, the chemical compositions derived from observations are not fully understood, as for instance in the case of the CH4/CO abundance ratio, which is often inferred different from what has been predicted by chemical models. Recently, the warm Neptune GJ3470b has been discovered and because of its close distance from us and high transit depth, it is a very promising candidate for follow up characterisation of its atmosphere. We study the atmospheric composition of GJ3470b in order to compare with the current observations of this planet, to prepare the future ones, but also as a typical case study to understand the chemical composition of warm (sub-)Neptunes. The metallicity of such atmospheres is totally uncertain, and vary probably to values up to 100x solar. We explore the space of unknown parameters to predict the range of possible atmospheric compositions. Wi...

  11. Mathematical Analysis of High-Temperature Co-electrolysis of CO2 and O2 Production in a Closed-Loop Atmosphere Revitalization System

    Energy Technology Data Exchange (ETDEWEB)

    Michael G. McKellar; Manohar S. Sohal; Lila Mulloth; Bernadette Luna; Morgan B. Abney

    2010-03-01

    NASA has been evaluating two closed-loop atmosphere revitalization architectures based on Sabatier and Bosch carbon dioxide, CO2, reduction technologies. The CO2 and steam, H2O, co-electrolysis process is another option that NASA has investigated. Utilizing recent advances in the fuel cell technology sector, the Idaho National Laboratory, INL, has developed a CO2 and H2O co-electrolysis process to produce oxygen and syngas (carbon monoxide, CO and hydrogen, H2 mixture) for terrestrial (energy production) application. The technology is a combined process that involves steam electrolysis, CO2 electrolysis, and the reverse water gas shift (RWGS) reaction. A number of process models have been developed and analyzed to determine the theoretical power required to recover oxygen, O2, in each case. These models include the current Sabatier and Bosch technologies and combinations of those processes with high-temperature co-electrolysis. The cases of constant CO2 supply and constant O2 production were evaluated. In addition, a process model of the hydrogenation process with co-electrolysis was developed and compared. Sabatier processes require the least amount of energy input per kg of oxygen produced. If co-electrolysis replaces solid polymer electrolyte (SPE) electrolysis within the Sabatier architecture, the power requirement is reduced by over 10%, but only if heat recuperation is used. Sabatier processes, however, require external water to achieve the lower power results. Under conditions of constant incoming carbon dioxide flow, the Sabatier architectures require more power than the other architectures. The Bosch, Boudouard with co-electrolysis, and the hydrogenation with co-electrolysis processes require little or no external water. The Bosch and hydrogenation processes produce water within their reactors, which aids in reducing the power requirement for electrolysis. The Boudouard with co-electrolysis process has a higher electrolysis power requirement because carbon

  12. Carbon dioxide, temperature, salinity, wind speed, air temperature, and atmospheric pressure collected via surface underway survey from R/V Aegaeo in Aegean Sea from February 8, 2006 to February 13, 2006 (NODC Accession 0084543)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0084543 includes chemical, meteorological, and physical underway data collected aboard the AEGAEO in Aegean Sea, and Mediterranean Sea from 8...

  13. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...... localities of tensions between matter and the immaterial, the practical and the ideal, and subject and object. In the colloquial language there can, moreover, often seem to be something authentic or genuine about atmosphere, juxtaposing it to staging, which is implied to be something simulated or artificial....... This introduction seeks to outline how a number of scholars have addressed the relationship between staged atmospheres and experience, and thus highlight both the philosophical, social and political aspects of atmospheres...

  14. Nutritional quality changes throughout shelf-life of fresh-cut kailan-hybrid and 'Parthenon' broccoli as affected by temperature and atmosphere composition.

    Science.gov (United States)

    Martínez-Hernández, Ginés Benito; Gómez, Perla A; Artés, Francisco; Artés-Hernández, Francisco

    2015-01-01

    The nutritional quality changes of the fresh-cut kailan-hybrid broccoli were compared with those of the 'Parthenon' cv. throughout 15 days at 2 ℃, 5 ℃ and 8 ℃ under air and modified atmosphere packaging. Florets showed higher dietary fiber content than stems. The total protein content of kailan-hybrid florets was 2.2-fold higher than that of 'Parthenon' cv. and higher amounts of S, Ca, Mg, Fe, Sr, Mn, Zn and Cu were found. However, 'Parthenon' florets registered higher initial total phenolics content than the kailan-hybrid edible part, followed by an increase throughout shelf-life favored at 5 ℃ and 8 ℃ under modified atmosphere packaging (5-7 kPa O2 + 14-15 kPa CO2). Modified atmosphere packaging stored samples at 8 ℃ showed higher individual phenolics content than modified atmosphere packaging stored samples at 2 ℃. The initial total antioxidant capacity of the kailan-hybrid edible part was higher than that of 'Parthenon' cv. florets. In conclusion, the kailan-hybrid florets generally showed healthier properties on the analyzed bioactive compounds, except total phenolic content, compared to the conventional 'Parthenon' cv.

  15. Solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon, and carbon monoxide in 1-butyl-3-methylimidazolium tetrafluoroborate between temperatures 283 K and 343 K and at pressures close to atmospheric

    International Nuclear Information System (INIS)

    Experimental values for the solubility of carbon dioxide, ethane, methane, oxygen, nitrogen, hydrogen, argon and carbon monoxide in 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4] - a room temperature ionic liquid - are reported as a function of temperature between 283 K and 343 K and at pressures close to atmospheric. Carbon dioxide is the most soluble gas with mole fraction solubilities of the order of 10-2. Ethane and methane are one order of magnitude more soluble than the other five gases that have mole fraction solubilities of the order of 10-4. Hydrogen is the less soluble of the gaseous solutes studied. From the variation of solubility, expressed as Henry's law constants, with temperature, the partial molar thermodynamic functions of solvation such as the standard Gibbs energy, the enthalpy, and the entropy are calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry's law constants from appropriate smoothing equations is of 1%

  16. Atmospheric Neutrinos

    OpenAIRE

    Takaaki Kajita

    2012-01-01

    Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith angle and energy-dependent deficit of muon-neutrino events. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses...

  17. Articulating Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie

    2011-01-01

    This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily...... experience in space, presented as middle ground experience. In the field of HCI, middle ground experiences complete the unarticulated spectrum between designing for foreground of attention or background awareness. When “Articulating Atmospheres through Middle Ground Experiences in Interaction Design...

  18. Pluto's atmosphere

    International Nuclear Information System (INIS)

    Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates observations; fits of the model to the immersion and emersion lightcurves exhibit no significant derived atmosphere-structure differences. Assuming a pure methane atmosphere, surface pressures of the order of 3 microbars are consistent with the occultation data. 43 references

  19. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d

  20. Emulating IPCC AR4 atmosphere-ocean and carbon cycle models for projecting global-mean, hemispheric and land/ocean temperatures: MAGICC 6.0

    OpenAIRE

    Meinshausen, M.; RAPER S.c.b.; Wigley, T. M. L.

    2008-01-01

    Current scientific knowledge on the future response of the climate system to human-induced perturbations is comprehensively captured by various model intercomparison efforts. In the preparation of the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), intercomparisons were organized for atmosphere-ocean general circulation models (AOGCMs) and carbon cycle models, named "CMIP3" and "C4MIP", respectively. Despite their tremendous value fo...

  1. Effects of 1-Methylcyclopropene and Modified Atmosphere Packaging on the Antioxidant Capacity in Pepper “Kulai” during Low-Temperature Storage

    OpenAIRE

    Chung Keat Tan; Zainon Mohd Ali; Ismanizan Ismail; Zamri Zainal

    2012-01-01

    The objective of the present study was to simultaneously evaluate the effect of a postharvest treatment on the pepper's antioxidant content and its ability to retain its economical value during the postharvest period. The fruits were pretreated by modified atmosphere packaging (MAP) with or without treatment with 1-methylcyclopropene (1-MCP) before cold storage at 10°C. Changes in the levels of non-enzymatic antioxidants, including the total phenolic, ascorbic acid levels and the total glutat...

  2. Atmospheres of Brown Dwarfs

    CERN Document Server

    Helling, Christiane

    2014-01-01

    Brown Dwarfs are the coolest class of stellar objects known to date. Our present perception is that Brown Dwarfs follow the principles of star formation, and that Brown Dwarfs share many characteristics with planets. Being the darkest and lowest mass stars known makes Brown Dwarfs also the coolest stars known. This has profound implication for their spectral fingerprints. Brown Dwarfs cover a range of effective temperatures which cause brown dwarfs atmospheres to be a sequence that gradually changes from a M-dwarf-like spectrum into a planet-like spectrum. This further implies that below an effective temperature of < 2800K, clouds form already in atmospheres of objects marking the boundary between M-Dwarfs and brown dwarfs. Recent developments have sparked the interest in plasma processes in such very cool atmospheres: sporadic and quiescent radio emission has been observed in combination with decaying Xray-activity indicators across the fully convective boundary.

  3. Sintering temperature and atmosphere modulated evolution of structure and luminescence of 2CaO–P{sub 2}O{sub 5}–B{sub 2}O{sub 3}: Eu phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chaofeng, E-mail: chaofengzhu@gmail.com [Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics of Shandong Province, Shandong Polytechnic University, Jinan 250353 (China); Key Laboratory of Amorphous and Polycrystalline Materials in Universities of Shandong, Shandong Polytechnic University, Jinan 250353 (China); Wang, Jia [Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics of Shandong Province, Shandong Polytechnic University, Jinan 250353 (China); Ren, Xiaorong [Instrumental Analysis Center, Shandong Polytechnic University, Jinan 250353 (China); Zhang, Yanfei; Liu, Shujiang; Shen, Jianxing [Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics of Shandong Province, Shandong Polytechnic University, Jinan 250353 (China); Yue, Yuanzheng, E-mail: yy@bio.aau.dk [Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics of Shandong Province, Shandong Polytechnic University, Jinan 250353 (China); Section of Chemistry, Aalborg University, Aalborg DK-9000 (Denmark)

    2014-01-15

    Europium doped 2CaO–P{sub 2}O{sub 5}–B{sub 2}O{sub 3} phosphors prepared via high temperature solid state reactions are reported. The evolution of luminescence and structure of the phosphors induced by variation of sintering temperature and atmosphere is investigated using photoluminescence spectra and X-ray diffraction techniques. We found that the optical performance and structure of the phosphors are sensitive to the sintering temperature and atmosphere. The luminescence intensity due to {sup 5}D{sub 0}→{sup 7}F{sub 2} transition of Eu{sup 3+} is decreased with increasing sintering temperature. CaBPO{sub 5} and BPO{sub 4} crystals co-exist in the as-prepared phosphors and the relative content of these two phases is dependent on sintering temperature. CaBPO{sub 5} crystal favors the transition of {sup 5}D{sub 0}→{sup 7}F{sub 1} of Eu{sup 3+} ions, while BPO{sub 4} enhances the emission of 612 nm. This study gives insight into the correlation between optical properties and structure of the as-prepared phosphors. The phosphors reported here are good candidates for light emitting diode applications. -- Highlights: • Eu doped 2CaO–P{sub 2}O{sub 5}–B{sub 2}O{sub 3} phosphors for LED applications are studied. • Effect of sintering conditions on optical property and structure is examined. • CaBPO{sub 5} favors the transition of {sup 5}D{sub 0}→{sup 7}F{sub 1} of Eu{sup 3+} in the investigated phosphors. • BPO{sub 4} enhances the emission of 612 nm of the phosphor.

  4. Photoacoustic study of the influence of the cooling temperature on the CO2 emission rate by Carica papaya L. in modified atmosphere

    Science.gov (United States)

    Schramm, D. U.; Sthel, M. S.; da Silva, M. G.; Carneiro, L. O.; Silva, H. R. F.; Martins, M. L. L.; Resende, E. D.; Vitorazi, L.; Vargas, H.

    2005-06-01

    The monitoring of trace gas emitted by papaya fruits and assessments of its mass loss can contribute to improve the conditions for their storage and transport. The C02 emission rate by the papaya fruits, monitored by a commercial infrared-based gas analyzer, was influenced by the temperature and storage time. The fruits stored at temperature of 13 °C accumulated more CO2 inside the PEBD bags than those fruits stored at 6 °C. The loss of mass of the fruits progressively increased with storage time for both temperatures until the saturation of the moisture inside the PEBD bag, been more pronounced at 13 ºC.

  5. Krypton and xenon in air trapped in polar ice cores : paleo-atmospheric measurements for estimating past mean ocean temperature and summer snowmelt frequency

    OpenAIRE

    Headly, Melissa Anne

    2008-01-01

    Krypton and xenon are highly soluble noble gases. Because they are inert, they do not react biologically or chemically, and therefore can trace purely physical processes. By taking advantage of both the inert nature of these gases and their high solubilities, krypton and xenon can be used to reconstruct past ocean temperature variations and summer snow melt frequency. Ocean temperature is a fundamental parameter of the climate system. It plays a vital role in the transport and storage of heat...

  6. On the use of the double floating probe method to infer the difference between the electron and the heavy particles temperatures in an atmospheric pressure, vortex-stabilized nitrogen plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Prevosto, L., E-mail: prevosto@waycom.com.ar; Mancinelli, B. R. [Grupo de Descargas Eléctricas, Departamento Ingeniería Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, 2600 Venado Tuerto, Santa Fe (Argentina); Kelly, H. [Grupo de Descargas Eléctricas, Departamento Ingeniería Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, 2600 Venado Tuerto, Santa Fe (Argentina); Instituto de Física del Plasma (CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria Pab. I, 1428 Buenos Aires (Argentina)

    2014-05-15

    Sweeping double probe measurements in an atmospheric pressure direct current vortex-stabilized plasma jet are reported (plasma conditions: 100 A discharge current, N{sub 2} gas flow rate of 25 Nl/min, thoriated tungsten rod-type cathode, copper anode with 5 mm inner diameter). The interpretation of the double probe characteristic was based on a generalization of the standard double floating probe formulae for non-uniform plasmas coupled to a non-equilibrium plasma composition model. Perturbations caused by the current to the probe together with collisional and thermal processes inside the probe perturbed region were taken into account. Radial values of the average electron and heavy particle temperatures as well as the electron density were obtained. The calculation of the temperature values did not require any specific assumption about a temperature relationship between different particle species. An electron temperature of 10 900 ± 900 K, a heavy particle temperature of 9300 ± 900 K, and an electron density of about 3.5 × 10{sup 22} m{sup −3} were found at the jet centre at 3.5 mm downstream from the torch exit. Large deviations from kinetic equilibrium were found toward the outer border of the plasma jet. These results showed good agreement with those previously reported by the authors by using a single probe technique. The calculations have shown that this method is particularly useful for studying spraying-type plasma torches operated at power levels of about 15 kW.

  7. Role of sea surface temperature, Arctic sea ice and Siberian snow in forcing the atmospheric circulation in winter of 2012–2013

    OpenAIRE

    Peings, Y.; Magnusdottir, G.

    2015-01-01

    © 2014 Springer-Verlag Berlin Heidelberg During the 2012–2013 winter, the negative phase of the North Atlantic Oscillation (NAO) predominated, resulting in a cold winter over Europe and northern Asia punctuated by episodes of frigid weather. This climate anomaly is part of a recent trend towards negative values of the NAO index that has occurred over recent winters. The negative trend of the NAO may be related to atmospheric internal variability but it may also be partly forced by slowly vary...

  8. Temperatura, umidade relativa e atraso na instalação da atmosfera controlada no armazenamento de maçã 'Fuji' Temperature, relative humidity and delay in installation of controlled atmosphere storage of the 'Fuji' apple

    Directory of Open Access Journals (Sweden)

    Auri Brackmann

    2009-11-01

    Full Text Available O objetivo deste trabalho foi avaliar o atraso na instalação da atmosfera controlada, da exposição à temperatura mais elevada (3°C e do uso de baixa umidade relativa no início do armazenamento sobre a qualidade da maçã da cultivar 'Fuji'. O delineamento experimental utilizado foi o inteiramente casualizado, com 10 tratamentos e quatro repetições. Os tratamentos avaliados consistiram de combinações de retardo na instalação da AC, por meio do AR, uso da alta temperatura (3°C e baixa umidade relativa (85%, por um período de um mês e posterior armazenamento em AC, com 1,0kPa de O2 + The aim of this research was to evaluate the delay in installation of a controlled atmosphere, exposure to highe temperature (3°C at the beginning of the storage period and use of low humidity also at the beginning of storage on the quality of apple 'Fuji'. The experimental design was a completely randomized with ten treatments and four replicates. The treatments evaluated were combinations of delay in installation of the CA, through RH, high temperature (3°C usage and low humidity (85% for a period of one month and later storage with AC 1.0kPa of O2 + <0.5kPa of CO2 in temperature of -0.5°C (RH 96%, use of AC in two temperatures (0.5 and -0.5°C, and also by exposure to high CO2 in the initial period of storage. The results showed that the use of low humidity associated or not to the temperature of 3°C in the first month of storage reduced the incidence of breakdown, decay and maintained the firmness of flesh. The temperature of -0.5°C is effective in reducing the incidence of breakdown, decay and maintenance of firmness when compared to the temperature of 0.5°C. The delay of the controlled installation atmosphere combined with a temperature of 3°C in the initial period of storage is not recommended because it causes high incidence of decay and low pulp firmness. The high partial pressure of CO2 or low O2 partial pressure of relevant causes

  9. Atmospheric-Pressure DBD Cold Plasma for Preparation of High Active Au/P25 Catalysts for Low-Temperature CO Oxidation

    Institute of Scientific and Technical Information of China (English)

    DI Lanbo; ZHAN Zhibin; ZHANG Xiuling; QI Bin; XU Weijie

    2016-01-01

    Cold plasma generated by dielectric barrier discharge (DBD) at atmospheric pressure was adopted for preparation of commercial TiO2 Degussa P25 supported Au catalysts (Au/P25-P) with the assistance of the deposition-precipitation procedure.The influences of the plasma reduction time and calcination on the performance of the Au/P25-P catalysts were investigated.CO oxidation was performed to investigate the catalytic activity of thc Au/P25 catalysts.The results show that DBD cold plasma for the fabrication of Au/P25-P catalysts is a fast process,and Au/P25-P (4 min) exhibited the highest CO oxidation activity due to the complete reduction of Au compounds and less consumption of oxygen vacancies.In order to form more oxygen vacancies active species,Au/P25-P was calcined to obtain Au/P25-PC catalysts.Interestingly,Au/P25-PC exhibited the highest activity for CO oxidation among the Au/P25 samples.The results of transmission electron microscopy (TEM) indicated that the smaller size and high distribution of Au nanoparticles are the mean reasons for a high performance of Au/P25-PC.Atmospheric-pressure DBD cold plasma was proved to be of great efficiency in preparing high performance supported Au catalysts.

  10. The Global Land-Ocean Temperature Index in Relation to Sunspot Number, the Atlantic Multidecadal Oscillation Index, the Mauna Loa Atmospheric Concentration of CO2, and Anthropogenic Carbon Emissions

    Science.gov (United States)

    Wilson, Robert M.

    2013-01-01

    Global warming/climate change has been a subject of scientific interest since the early 19th century. In particular, increases in the atmospheric concentration of carbon dioxide (CO2) have long been thought to account for Earth's increased warming, although the lack of a dependable set of observational data was apparent as late as the mid 1950s. However, beginning in the late 1950s, being associated with the International Geophysical Year, the opportunity arose to begin accurate continuous monitoring of the Earth's atmospheric concentration of CO2. Consequently, it is now well established that the atmospheric concentration of CO2, while varying seasonally within any particular year, has steadily increased over time. Associated with this rising trend in the atmospheric concentration of CO2 is a rising trend in the surface-air and sea-surface temperatures (SSTs). This Technical Publication (TP) examines the statistical relationships between 10-year moving averages (10-yma) of the Global Land-Ocean Temperature Index (GLOTI), sunspot number (SSN), the Atlantic Multidecadal Oscillation (AMO) index, and the Mauna Loa CO2 (MLCO2) index for the common interval 1964-2006, where the 10-yma values are used to indicate trends in the data. Scatter plots using the 10-yma values between GLOTI and each of the other parameters are determined, both as single-variate and multivariate fits. Scatter plots are also determined for MLCO2 using single-variate and bivariate (BV) fits, based on the GLOTI alone and the GLOTI in combination with the AMO index. On the basis of the inferred preferential fits for MLCO2, estimates for MLCO2 are determined for the interval 1885-1964, thereby yielding an estimate of the preindustrial level of atmospheric concentration of CO2. Lastly, 10-yma values of MLCO2 are compared against 10-yma estimates of the total carbon emissions (TCE) to determine the likelihood that manmade sources of carbon emissions are indeed responsible for the recent warming now

  11. Greenhouse effect in the atmosphere

    Science.gov (United States)

    Smirnov, B. M.

    2016-04-01

    Average optical atmospheric parameters for the infrared spectrum range are evaluated on the basis of the Earth energetic balance and parameters of the standard atmosphere. The average optical thickness of the atmosphere is u ≈ 2.5 and this atmospheric emission is originated at altitudes below 10 km. Variations of atmospheric radiative fluxes towards the Earth and outward are calculated as a function of the concentration of \\text{CO}2 molecules for the regular model of molecular spectrum. As a result of doubling of the \\text{CO}2 concentration the change of the global Earth temperature is (0.4 +/- 0.2) \\text{K} if other atmospheric parameters are conserved compared to the value (3.0 +/- 1.5) \\text{K} under real atmospheric conditions with the variation of the amount of atmospheric water. An observed variation of the global Earth temperature during the last century (0.8 ^\\circ \\text{C}) follows from an increase of the mass of atmospheric water by 7% or by conversion of 1% of atmospheric water in aerosols.

  12. Atmospheric composition

    Science.gov (United States)

    Daniels, G. E.

    1973-01-01

    The earth's atmosphere is made up of a number of gases in different relative amounts. Near sea level and up to about 90 km, the amount of these atmospheric gases in clean, relatively dry air is practically constant. Four of these gases, nitrogen, oxygen, argon, and carbon dioxide, make up 99.99 percent by volume of the atmosphere. Two gases, ozone and water vapor, change in relative amounts, but the total amount of these two is very small compared to the amount of the other gases. The atmospheric composition shown in a table can be considered valid up to 90 km geometric altitude. Above 90 km, mainly because of molecular dissociation and diffusive separation, the composition changes.

  13. NUMERICAL STUDY OF THE EFFECTS OF PERSISTENT WARMER SEA SURFACE TEMPERATURE IN TROPICAL INDIAN OCEAN ON ATMOSPHERIC CIRCULATION IN THE EARLY SUMMER IN EAST ASIA IN 1991

    Institute of Scientific and Technical Information of China (English)

    袁佳双; 郑庆林

    2004-01-01

    By employing the CCM1(R15L12)long-range spectral model, study is undertaken of the effects of sea surface temperature anomaly(SSTA) for tropical Indian ocean on circulation transformation in the early summer in East Asia in 1991. The results indicate that warmer SSTA contributes to the increasing of the temperature over the Plateau in early summer, resulting in the intensification of tropical easterly jet on 100 hPa and northward shift of Northern Hemisphere subtropical westerly jet in May. It is obviously favorable for the subtropical high enhancement over western Pacific Ocean in May and subtropical westerly jet maintaining at 35~40 (N in June, making the Mei-Yu come earlier and stay over the Changjiang basin in 1991. Furthermore, warmer SSTA is also advantageous to averaged temperature rise in East Asia land region and Nanhai monsoon development. These roles are helpful in accelerating the seasonal transition for East Asia in early summer.By employing the CCM1(R15L12)long-range spectral model, study is undertaken of the effects of sea surface temperature anomaly(SSTA) for tropical Indian ocean on circulation transformation in the early summer in East Asia in 1991. The results indicate that warmer SSTA contributes to the increasing of the temperature over the Plateau in early summer, resulting in the intensification of tropical easterly jet on 100 hPa and northward shift of Northern Hemisphere subtropical westerly jet in May. It is obviously favorable for the subtropical high enhancement over western Pacific Ocean in May and subtropical westerly jet maintaining at 35~40 (N in June, making the Mei-Yu come earlier and stay over the Changjiang basin in 1991. Furthermore, warmer SSTA is also advantageous to averaged temperature rise in East Asia land region and Nanhai monsoon development. These roles are helpful in accelerating the seasonal transition for East Asia in early summer.

  14. Experimental aspects of stress-strain curves determination at high temperature and controlled atmosphere: Al{sub 2}O{sub 3}-MgO-C refractories; Aspectos experimentales de la determinacion de curvas esfuerzo-deformacion a alta temperatura y en atmosfera controlada: Refractarios Al{sub 2}O{sub 3}-MgO-C

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, V.; Rohr, G. A.; Tomba Martinez, A. G.; Cavalieri, A. L.

    2011-07-01

    A methodology for the mechanical evaluation of refractory materials at high temperatures and controlled atmosphere, designed and implemented in the Structural Materials Laboratory of Ceramics Division of INTEMA, is described. The methodology includes the measurement of the specimen deformation by contact extensometry in compression tests to obtain stress-strain curves and the use of a gaseous flow as a system to control atmosphere. The determination of stress-strain curves of Al{sub 2}O{sub 3}-MgO-C commercial refractories used in steelmaking ladles at room temperature and 1260 degree centigrade in different atmospheres is presented as an example of application of this methodology. (Author) 34 refs.

  15. Atmospheric-Pressure DBD Cold Plasma for Preparation of High Active Au/P25 Catalysts for Low-Temperature CO Oxidation

    Science.gov (United States)

    Di, Lanbo; Zhan, Zhibin; Zhang, Xiuling; Qi, Bin; Xu, Weijie

    2016-05-01

    Cold plasma generated by dielectric barrier discharge (DBD) at atmospheric pressure was adopted for preparation of commercial TiO2 Degussa P25 supported Au catalysts (Au/P25-P) with the assistance of the deposition-precipitation procedure. The influences of the plasma reduction time and calcination on the performance of the Au/P25-P catalysts were investigated. CO oxidation was performed to investigate the catalytic activity of the Au/P25 catalysts. The results show that DBD cold plasma for the fabrication of Au/P25-P catalysts is a fast process, and Au/P25-P (4 min) exhibited the highest CO oxidation activity due to the complete reduction of Au compounds and less consumption of oxygen vacancies. In order to form more oxygen vacancies active species, Au/P25-P was calcined to obtain Au/P25-PC catalysts. Interestingly, Au/P25-PC exhibited the highest activity for CO oxidation among the Au/P25 samples. The results of transmission electron microscopy (TEM) indicated that the smaller size and high distribution of Au nanoparticles are the mean reasons for a high performance of Au/P25-PC. Atmospheric-pressure DBD cold plasma was proved to be of great efficiency in preparing high performance supported Au catalysts. supported by National Natural Science Foundation of China (Nos. 11505019, 21173028), the Science and Technology Research Project of Liaoning Provincial Education Department (No. L2013464), the Scientific Research Foundation for the Doctor of Liaoning Province (No. 20131004), and the Dalian Jinzhou New District Science and Technology Plan Project (No. KJCX-ZTPY-2014-0001)

  16. Development of an Operational Calibration Methodology for the Landsat Thermal Data Archive and Initial Testing of the Atmospheric Compensation Component of a Land Surface Temperature (LST Product from the Archive

    Directory of Open Access Journals (Sweden)

    Monica Cook

    2014-11-01

    Full Text Available The Landsat program has been producing an archive of thermal imagery that spans the globe and covers 30 years of the thermal history of the planet at human scales (60–120 m. Most of that archive’s absolute radiometric calibration has been fixed through vicarious calibration techniques. These calibration ties to trusted values have often taken a year or more to gather sufficient data and, in some cases, it has been over a decade before calibration certainty has been established. With temperature being such a critical factor for all living systems and the ongoing concern over the impacts of climate change, NASA and the United States Geological Survey (USGS are leading efforts to provide timely and accurate temperature data from the Landsat thermal data archive. This paper discusses two closely related advances that are critical steps toward providing timely and reliable temperature image maps from Landsat. The first advance involves the development and testing of an autonomous procedure for gathering and performing initial screening of large amounts of vicarious calibration data. The second advance discussed in this paper is the per-pixel atmospheric compensation of the data to permit calculation of the emitted surface radiance (using ancillary sources of emissivity data and the corresponding land surface temperature (LST.

  17. Maine River Temperature Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We collect seasonal and annual temperature measurements on an hourly or quarter hourly basis to monitor habitat suitability for ATS and other species. Temperature...

  18. A Power Interruption Technique for Investigation of Temperature Difference in Stabilized Low Direct-Current Arc Burning in Pure Argon on Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    M. M. Kuzmanovi(c); J. J. Savovi(c); D. P. Rankovi(c); M. Stoiljkovi(c); A. Anti(c)-Jovanovi(c); M.S. Pavlovi(c); M. Marinkovi(c)

    2008-01-01

    @@ Plasma of argon stabilized arc column, in a current range 3-11 A, is investigated using emission spectrometric diagnostic techniques. Temperatures are evaluated using several methods: argon line to adjacent recombinational continuum intensity ratio, absolute emissivity of argon fine, measurement of electron number density, and power interruption. Electron number density is evaluated from absolute emissivity of recombinational continuum. The difference between electron Te and heavy particle Th temperature ranged from 4500 K for 3 A to 2300 K for 11 A arc current. By comparing the present with the previously obtained results, using the same arc device but with the introduction of water aerosol, it is concluded that water aerosol reduces the difference Te - Th and brings plasma closer to the partial thermodynamic equilibrium state.

  19. Effect of Elevated Atmospheric CO2 and Temperature on the Disease Severity of Rocket Plants Caused by Fusarium Wilt under Phytotron Conditions.

    Directory of Open Access Journals (Sweden)

    Walter Chitarra

    Full Text Available The severity of F. oxysporum f.sp. conglutinans on rocket plants grown under simulated climate change conditions has been studied. The rocket plants were cultivated on an infested substrate (4 log CFU g-1 and a non-infested substrate over three cycles. Pots were placed in six phytotrons in order to simulate different environmental conditions: 1 400-450 ppm CO2, 18-22°C; 2 800-850 ppm CO2, 18-22°C; 3 400-450 ppm CO2, 22-26°C, 4 800-850 ppm CO2, 22-26°C, 5 400-450 ppm CO2, 26-30°C; 6 800-850 ppm CO2, 26-30°C. Substrates from the infested and control samples were collected from each phytotron at 0, 60 and 120 days after transplanting. The disease index, microbial abundance, leaf physiological performances, root exudates and variability in the fungal profiles were monitored. The disease index was found to be significantly influenced by higher levels of temperature and CO2. Plate counts showed that fungal and bacterial development was not affected by the different CO2 and temperature levels, but a significant decreasing trend was observed from 0 up to 120 days. Conversely, the F. oxysporum f.sp. conglutinans plate counts did not show any significantly decrease from 0 up to 120 days. The fungal profiles, evaluated by means of polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE, showed a relationship to temperature and CO2 on fungal diversity profiles. Different exudation patterns were observed when the controls and infested plants were compared, and it was found that both CO2 and temperature can influence the release of compounds from the roots of rocket plants. In short, the results show that global climate changes could influence disease incidence, probably through plant-mediated effects, caused by soilborne pathogens.

  20. Effect of Elevated Atmospheric CO2 and Temperature on the Disease Severity of Rocket Plants Caused by Fusarium Wilt under Phytotron Conditions.

    Science.gov (United States)

    Chitarra, Walter; Siciliano, Ilenia; Ferrocino, Ilario; Gullino, Maria Lodovica; Garibaldi, Angelo

    2015-01-01

    The severity of F. oxysporum f.sp. conglutinans on rocket plants grown under simulated climate change conditions has been studied. The rocket plants were cultivated on an infested substrate (4 log CFU g-1) and a non-infested substrate over three cycles. Pots were placed in six phytotrons in order to simulate different environmental conditions: 1) 400-450 ppm CO2, 18-22°C; 2) 800-850 ppm CO2, 18-22°C; 3) 400-450 ppm CO2, 22-26°C, 4) 800-850 ppm CO2, 22-26°C, 5) 400-450 ppm CO2, 26-30°C; 6) 800-850 ppm CO2, 26-30°C. Substrates from the infested and control samples were collected from each phytotron at 0, 60 and 120 days after transplanting. The disease index, microbial abundance, leaf physiological performances, root exudates and variability in the fungal profiles were monitored. The disease index was found to be significantly influenced by higher levels of temperature and CO2. Plate counts showed that fungal and bacterial development was not affected by the different CO2 and temperature levels, but a significant decreasing trend was observed from 0 up to 120 days. Conversely, the F. oxysporum f.sp. conglutinans plate counts did not show any significantly decrease from 0 up to 120 days. The fungal profiles, evaluated by means of polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE), showed a relationship to temperature and CO2 on fungal diversity profiles. Different exudation patterns were observed when the controls and infested plants were compared, and it was found that both CO2 and temperature can influence the release of compounds from the roots of rocket plants. In short, the results show that global climate changes could influence disease incidence, probably through plant-mediated effects, caused by soilborne pathogens.

  1. The meridional temperature gradient in the eastern North Atlantic during MIS 11 and its link to the ocean–atmosphere system

    OpenAIRE

    Kandiano, E. S.; H. A. Bauch; K. Fahl; J. P. Helmke; Röhl, U.; Pérez-Folgado, M.; Cacho, I.

    2012-01-01

    Temporal and spatial patterns in eastern North Atlantic sea surface temperatures (SST) were reconstructed for marine isotope stage (MIS) 11c using a submeridional transect of five sediment cores. The SST reconstructions are based on planktic foraminiferal abundances and alkenone indices, and are supported by benthic and planktic stable isotope measurements, as well as by ice-rafted debris content in polar and middle latitudes. Additionally, the larger-scale dynamics of the precipitation regim...

  2. 大气湿球温度计算的牛顿迭代法%Newton Iteration Method of Atmospheric Wet-bulb Temperature Calculation

    Institute of Scientific and Technical Information of China (English)

    潘晓春; 程春龙

    2015-01-01

    基于对饱和水汽压的求导,提出湿球温度计算的牛顿迭代法。本法具有迭代速度快、成果精度高以及适用范围广等优点。结合算例指出,由于相对湿度观测值含有较大的舍入误差,由此计算的湿球温度精度相对较低,建议尽量采用水汽压来计算湿球温度。%Based on the saturation vapor pressure function derivative calculation, Newton iteration method was proposed to calculate the wet-bulb temperature, which is with high iteration speed and high precision and wide application. It is found that the wet-bulb temperature calculation precision according to the relative humidity formula was lower than to the vapor pressure formula as the relative humidity observed values have lager rounding errors, and the vapor pressure formula was recommended to calculate the wet-bulb temperature.

  3. Atmospheric Photochemistry

    Science.gov (United States)

    Massey, Harrie; Potter, A. E.

    1961-01-01

    The upper atmosphere offers a vast photochemical laboratory free from solid surfaces, so all reactions take place in the gaseous phase. At 30 km altitude the pressure has fallen to about one-hundredth of that at ground level, and we shall, rather arbitrarily, regard the upper atmosphere as beginning at that height. By a little less than 100 km the pressure has fallen to 10(exp -3) mm Hg and is decreasing by a power of ten for every 15 km increase in altitude. Essentially we are concerned then with the photochemistry of a nitrogen-oxygen mixture under low-pressure conditions in which photo-ionization, as well as photodissociation, plays an important part. Account must also be taken of the presence of rare constituents, such as water vapour and its decomposition products, including particularly hydroxyl, oxides of carbon, methane and, strangely enough, sodium, lithium and calcium. Many curious and unfamiliar reactions occur in the upper atmosphere. Some of them are luminescent, causing the atmosphere to emit a dim light called the airglow. Others, between gaseous ions and neutral molecules, are almost a complete mystery at this time. Similar interesting phenomena must occur in other planetary atmospheres, and they might be predicted if sufficient chemical information were available.

  4. 金属燃料在不同气氛中的点火温度%Ignition Temperature of Metal Fuel in Different Atmosphere

    Institute of Scientific and Technical Information of China (English)

    秦钊; Christian PARAVAN; Giovanni COLOMOBO; Luigi T.DELUCA; 沈瑞琪; 叶迎华

    2014-01-01

    Ignition temperature of Mg, B coated by Mg (coating rate 20%) and alloy am-Al in air and oxygen at ambient pressure were studied, by use of self-designed experiment system. The result shows, ignition temperature in oxygen of all three metals are lower than that in air, B coated by Mg can significantly lower ignition point of B, and accelerate ignition and burning of B. Meanwhile, it is much easier for B coated by Mg to burn in oxygen, and the ignition temperature is only 195.92℃. Alloy am-Al can be ignited in oxygen, and the ignition temperature is lower than that of Mg. Among these three metal, alloy am-Al release much more heat during combustion compared with other two powders, ignition temperature of B coated by Mg and alloy am-Al are lower than 300℃, thus, both of them can be used as high calorific value metal fuel.%利用自行设计的金属燃料点火温度测试系统,测试了常压下分别在空气和氧气中的镁包覆硼粉(包覆度20%)、镁粉及铝合金am-Al的点火温度。结果表明,与在空气中相比,3种金属燃料在氧气中的点火温度均有所降低;镁包覆硼粉有效降低了硼的燃点,促进了硼的点火和燃烧,且镁包覆硼粉在氧气中更易燃烧,其点火温度仅为约195.92℃;am-Al在氧气中可点燃,其点火温度低于镁,且燃烧放出的热量最高。在充足的氧气环境下,镁包覆硼粉及am-Al的点火温度均低于300℃,二者均可用作高热值金属燃料。

  5. Ignition Temperature of Metal Fuel in Different Atmosphere%金属燃料在不同气氛中的点火温度

    Institute of Scientific and Technical Information of China (English)

    秦钊; Christian PARAVAN; Giovanni COLOMOBO; Luigi T.DELUCA; 沈瑞琪; 叶迎华

    2014-01-01

    利用自行设计的金属燃料点火温度测试系统,测试了常压下分别在空气和氧气中的镁包覆硼粉(包覆度20%)、镁粉及铝合金am-Al的点火温度。结果表明,与在空气中相比,3种金属燃料在氧气中的点火温度均有所降低;镁包覆硼粉有效降低了硼的燃点,促进了硼的点火和燃烧,且镁包覆硼粉在氧气中更易燃烧,其点火温度仅为约195.92℃;am-Al在氧气中可点燃,其点火温度低于镁,且燃烧放出的热量最高。在充足的氧气环境下,镁包覆硼粉及am-Al的点火温度均低于300℃,二者均可用作高热值金属燃料。%Ignition temperature of Mg, B coated by Mg (coating rate 20%) and alloy am-Al in air and oxygen at ambient pressure were studied, by use of self-designed experiment system. The result shows, ignition temperature in oxygen of all three metals are lower than that in air, B coated by Mg can significantly lower ignition point of B, and accelerate ignition and burning of B. Meanwhile, it is much easier for B coated by Mg to burn in oxygen, and the ignition temperature is only 195.92℃. Alloy am-Al can be ignited in oxygen, and the ignition temperature is lower than that of Mg. Among these three metal, alloy am-Al release much more heat during combustion compared with other two powders, ignition temperature of B coated by Mg and alloy am-Al are lower than 300℃, thus, both of them can be used as high calorific value metal fuel.

  6. Phase evolution of vanadium oxides obtained through temperature programmed calcinations of ammonium vanadate in hydrogen atmosphere and their humidity sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Akande, A.A. [DST/CSIR National Centre for Nano-Structured Materials, P O Box 395, Pretoria, 0001 (South Africa); University of Limpopo, Department of Physics, P/Bag X1106, Sovenga, 0727 (South Africa); Linganiso, E.C.; Dhonge, B.P. [DST/CSIR National Centre for Nano-Structured Materials, P O Box 395, Pretoria, 0001 (South Africa); Rammutla, K.E. [University of Limpopo, Department of Physics, P/Bag X1106, Sovenga, 0727 (South Africa); Machatine, A.; Prinsloo, L.; Kunert, H. [School of Physics, University of Pretoria, Pretoria, 0002 (South Africa); Mwakikunga, B.W., E-mail: bmwakikunga@csir.co.za [DST/CSIR National Centre for Nano-Structured Materials, P O Box 395, Pretoria, 0001 (South Africa)

    2015-02-01

    The possibility of obtaining vanadium dioxide (VO{sub 2}) [wherein the vanadium ionic state is 4{sup +}] from a precursor of ammonium metavanadate (NH{sub 4}VO{sub 3}) bearing the ion V{sup 5+} is investigated. The reduction is carried out by calcining the NH{sub 4}VO{sub 3} powders in similar concentrations of H{sub 2} flow at varying temperatures. The resulting powders have been studied by several techniques including XRD, Raman spectroscopy, FTIR, TEM, BET and DSC. It is found that remnants of bright yellow V{sup 5+} still exist up to calcination temperatures of 100 °C after which the sky-blue VO{sub 2} dominates at calcination temperatures of 150 °C–250 °C. There is a population surge of metastable dark-blue V{sub 6}O{sub 13} (where V is in between V{sup 4+} and V{sup 5+} ionic states) between 250 °C and 300 °C. However above 350 °C the material reverts to the stable V{sup 5+} in the yellow–orange V{sub 2}O{sub 5}. XPS/EDS and VSM confirm the order of appearance to be VO{sub 2}(150 °C) → V{sub 6}O{sub 13}(200 °C) → V{sub 2}O{sub 5} (350 °C). - Highlights: • Validated the theoretical mass losses at each temperature of NH{sub 4}VO{sub 3} with TGA. • Confirmed mechanisms of formation of various stoichiometries of VO{sub x} from NH{sub 4}VO{sub 3}. • Determined the evolution of VO{sub 2}, V{sub 6}O{sub 13} and V{sub 2}O{sub 5} with temperature. • Phase diagram of VO{sub 2}, V{sub 6}O{sub 13} and V{sub 2}O{sub 5} by VSM, XPS/EDS, XRD and Raman spectra. • Comparative response of VO{sub 2}, V{sub 6}O{sub 13} and V{sub 2}O{sub 5} to humidity.

  7. A synthesis data-model integration of the 5-year response of ecosystem respiration to altered temperature, moisture and atmospheric CO2

    Science.gov (United States)

    Ryan, E.; Ogle, K.; Pendall, E. G.

    2013-12-01

    Warming and elevated CO2 may increase biomass and ecosystem respiration in grasslands and an improved understanding of the mechanisms underlying these responses is expected to improve terrestrial C cycle predictions. The goal of this study is to evaluate the temporal dynamics of ecosystem respiration (Reco) and quantify the potential drivers affecting Reco in the context of the Prairie Heating and CO2 Enrichment (PHACE) experiment, a semi-arid grassland in southeastern Wyoming. PHACE consists of 6 treatments: ambient CO2 and temperature (ct); ambient CO2 and elevated temperature (cT); elevated CO2 and ambient temperature (Ct); elevated CO2 and temperature (CT); shallow irrigation (cts) and deep irrigation (ctd). Reco was measured on 96 days, spaced 2-4 weeks apart, between May 2007 and April 2012. Every 6 weeks, plots were measured 5 times during the day between 04:00-21:00; otherwise, plots were only measured at midday. Soil temperature (T, 3 and 10 cm depth), soil water content (SWC, 5-10 cm), vapor pressure deficit (VPD), and photosynthetically active radiation (PAR) were continuously recorded at the plot (T, SWC) and site (VPD, PAR) scales. We quantified ';aboveground activity' as a function of vegetation greenness, VPD, and PAR. We analyzed the Reco data in the context of a semi-mechanistic respiration model that is described by two components: (i) the Reco rate at a reference T of 10 degrees Celsius (i.e., Rb) and (ii) the sensitivity of Reco to changes in T (i.e., Eo). We subsequently modeled both Rb and Eo as functions of antecedent and current SWC and aboveground activity, and we allowed for potential temperature acclimation of Eo by incorporating an antecedent T effect. We used the data-informed model to predict daily Reco over the 5-year study period to evaluate the potential effects of the global change treatments on the temporal dynamics of Reco and cumulative ecosystem C loss. The model fit the Reco data well (R squared = 0.76), and the aboveground

  8. Interaction of Ce{sub 1−x}Er{sub x}O{sub 2−y} nanoparticles with SiO{sub 2}-effect of temperature and atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kepinski, L., E-mail: L.Kepinski@int.pan.wroc.pl; Krajczyk, L.; Mista, W.

    2014-01-15

    Morphology, microstructure and phase evolution of homogeneous, nanocrystalline Ce{sub 1−x}Er{sub x}O{sub 2−x/2} mixed oxide (x=0.3 and 0.5), prepared by microemulsion method, supported on amorphous SiO{sub 2} was studied in oxidizing and reducing atmosphere by XRD, TEM, SEM-EDS and N{sub 2} adsorption. The system is structurally and chemically stable in the oxidizing atmosphere up to 1000 °C, exhibiting only a small increase of the mean crystallite size of the oxide to ∼4 nm. At 1100 °C formation of Er silicate with unusual structure isomorphic with y-Y{sub 2}Si{sub 2}O{sub 7} (yttrialite), stabilized by Ce{sup 4+} ions was observed. In the reducing atmosphere the Ce{sub 1−x}Er{sub x}O{sub 2−x/2} reacted with SiO{sub 2} already at 900 °C, due to high affinity of the reduced Ce{sup 3+} to form a silicate phase. At higher temperature the silicate crystallized into the tetragonal, low temperature A-(Ce{sub 1−x}Er{sub x}){sub 2}Si{sub 2}O{sub 7} polymorph. Such systems, containing nanocrystalline silicate particles with Er{sup 3+} ions placed in well defined sites embedded in silica matrix, may be interesting as highly efficient active components of optical waveguides amplifiers integrated with Si microelectronics. The nanocrystalline Ce–Er–O/SiO{sub 2} system prepared by the impregnation of the silica with the aqueous solution of nitrates appeared to be chemically inhomogeneous and less stable in both oxidising and reducing atmosphere. - Graphical abstract: Structure evolution of Ce{sub 0.5}Er{sub 0.5}O{sub 1.75} in air and in H{sub 2}. Display Omitted - Highlights: • Homogeneous 3 nm Ce{sub 1−x}Er{sub x}O{sub 2−y} particles were prepared and uniformly dispersed on SiO{sub 2}. • Er diffusion to SiO{sub 2} determines the stability of the mixed oxide in air to ∼1000 °C. • Spreading of Ce{sub 1−x}Er{sub x}O{sub 2−y} onto SiO{sub 2} occurs in hydrogen at 900 °C. • Nanocrystalline A-(Ce,Er){sub 2}Si{sub 2}O{sub 7} silicate forms in H

  9. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  10. Effects of 1-Methylcyclopropene and Modified Atmosphere Packaging on the Antioxidant Capacity in Pepper “Kulai” during Low-Temperature Storage

    Directory of Open Access Journals (Sweden)

    Chung Keat Tan

    2012-01-01

    Full Text Available The objective of the present study was to simultaneously evaluate the effect of a postharvest treatment on the pepper's antioxidant content and its ability to retain its economical value during the postharvest period. The fruits were pretreated by modified atmosphere packaging (MAP with or without treatment with 1-methylcyclopropene (1-MCP before cold storage at 10°C. Changes in the levels of non-enzymatic antioxidants, including the total phenolic, ascorbic acid levels and the total glutathione level, as well as enzymatic antioxidants, including ascorbate peroxidase (APX, glutathione reductase (GR, and catalase (CAT, were determined. Both treatments successfully extended the shelf life of the fruit for up to 25 days, and a high level of antioxidant capacity was maintained throughout the storage period. However, 1-MCP treatment maintained the high antioxidant capacity for a longer period of time. The 1-MCP-treated peppers maintained high levels of phenolic content, a high reduced glutathione (GSH/oxidised glutathione (GSSG ratio, decreased levels of ascorbic acid and CAT activity, and increased levels of APX and GR compared with the peppers that were not treated with 1-MCP. The overall results suggested that a combination of 1-MCP and MAP was the most effective treatment for extending shelf life while retaining the nutritional benefits.

  11. A Simple Drought Product and Indicator Derived from Temperature and Relative Humidity Observed by the Atmospheric InfraRed Sounder (AIRS)

    Science.gov (United States)

    Granger, S. L.; Behrangi, A.

    2015-12-01

    In the United States, drought results in agricultural losses, impacts to industry, power and energy production, natural resources, municipal water supplies and human health making it one of the costliest natural hazards in the nation. Monitoring drought is therefore critical to help local governments, resource managers, and other groups make effective decisions, yet there is no single definition of drought, and because of the complex nature of drought there is no universal best drought indicator. Remote sensing applications in drought monitoring are advantageous due to the large spatial and temporal frequency of observations, leading to a better understanding of the spatial extent of drought and its duration, and in detecting the onset of drought and its intensity. NASA Earth Observing System (EOS)-era data have potential for monitoring and assessing drought and many are already used either directly or indirectly for drought monitoring. Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) observations from the Moderate Resolution Imaging Spectro-radiometer (MODIS) sensor are widely used for agricultural and environmental plant-stress monitoring via the USDM, the VegDRI project and FEWSNet. However there remain underutilized sources of information from NASA satellite observations that may have promise for characterizing and understanding meteorological drought. Once such sensor is NASA's Advanced Infra-Red Sounder (AIRS) aboard the Aqua satellite. AIRS and it's sister sensor the Advanced Microwave Sounding Unit (AMSU) that together provide meteorological information of high relevance to meteorological drought, e.g., profiles of water vapor, surface air temperature, and precipitation. Recent work undertaken to develop simple indicators of drought based on temperature and relative humidity from the AIRS suite of instruments is promising. Although there are more sophisticated indicators developed through the application of a variety of

  12. Building long-term and high spatio-temporal resolution precipitation and air temperature reanalyses by mixing local observations and global atmospheric reanalyses: the ANATEM method

    Directory of Open Access Journals (Sweden)

    A. Kuentz

    2015-01-01

    Full Text Available Improving the understanding of past climatic or hydrologic variability has received a large attention in different fields of geosciences, such as glaciology, dendrochronology, sedimentology or hydrology. Based on different proxies, each research community produces different kind of climatic or hydrologic reanalyses, at different spatio-temporal scales and resolution. When considering climate or hydrology, numerous studies aim at characterising variability, trends or breaks using observed time-series of different regions or climate of world. However, in hydrology, these studies are usually limited to reduced temporal scale (mainly few decades, seldomly a century because they are limited to observed time-series, that suffers from a limited spatio-temporal density. This paper introduces a new model, ANATEM, based on a combination of local observations and large scale climatic informations (such as 20CR Reanalysis. This model allow to build long-term air temperature and precipitation time-series, with a high spatio-temporal resolution (daily time-step, few km2. ANATEM was tested on the air temperature and precipitation time-series of 22 watersheds situated on the Durance watershed, in the french Alps. Based on a multi-criteria and multi-scale diagnostic, the results show that ANATEM improves the performances of classical statistical models. ANATEM model have been validated on a regional level, improving spatial homogeneity of performances and on independent long-term time-series, being able to capture the regional low-frequency variabilities over more than a century (1883–2010.

  13. Atmospheric Dispositifs

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2015-01-01

    as a spatial phenomenon, exploring a multiplicity of conditions that constitute their resonant origins – i.e. the production sites from and within they have emerged. The intention is also to argue that despite the fact that atmosphere as an aesthetic category has crystallised over the last few decades...

  14. High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suit Gas Processing System (GPS) Carbon Dioxide Scrubber

    Science.gov (United States)

    Gundersen, Cynthia; Hoffman, Christopher; Munoz, Bruno; Steohenson, Timothy; Thomas, Walter

    2008-01-01

    In support of the GPS for the SAM instrument suite built by GSFC, a life test facility was developed to test the suitability of 80Ni-20Cr wire, 0.0056 inches in diameter, for use as a heater element for the carbon dioxide scrubber. The wire would be required to operate at 1000 C in order to attain the 800 C required for regeneration of the getter. The wire also would need to operate in the Mars atmosphere, which consists mostly of CO2 at pressures between 4 and 12 torr. Data on the high temperature degradation mechanism of 80Ni-20Cr in low pressure CO2, together with the effects of thermal cycling, were unknown. In addition, the influence of work hardening of the wire during assembly and the potential for catastrophic grain growth also were unknown. Verification of the wire reliability as defined by the mission goals required the construction of a test facility that would accurately simulate the duty cycles in a simulated Mars atmosphere. The experimental set-up, along with the test protocol and results will be described.

  15. High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suite Gas Processing System (GPS) Carbon Dioxide Scrubber

    Science.gov (United States)

    Hoffman, Christopher; Munoz, Bruno; Gundersen, Cynthia; Thomas, Walter, III; Stephenson, Timothy

    2008-01-01

    In support of the GPS for the SAM instrument suite built by NASA/GSFC, a life test facility was developed to test the suitability of 80Ni-20Cr alloy wire, 0.0142 cm diameter, for use as a heater element for the carbon dioxide scrubber. The element would be required to operate at 1000 C in order to attain the 800 C required for regeneration of the getter. The element also would need to operate in the Mars atmosphere, which consists mostly of CO2 at pressures between 4 and 12 torr. Data on the high temperature degradation mechanism of 80Ni- 20Cr in low pressure CO2, coupled with the effects of thermal cycling, were unknown. In addition, the influence of work hardening of the wire during assembly and the potential for catastrophic grain growth also were unknown. Verification of the element reliability as defined by the mission goals required the construction of a test facility that would accurately simulate the duty cycles in a simulated Mars atmosphere. The experimental set-up, along with the test protocol and results will be described.

  16. Responses of enchytraeids to increased temperature, drought and atmospheric CO2: Results of an eight-year field experiment in dry heathland

    DEFF Research Database (Denmark)

    Holmstrup, Martin; Schmelz, Rüdiger M.; Carrera, Noela;

    2015-01-01

    assessments of enchytraeids in the CLIMAITE experiment shows that the severity of drought and the time elapsed since the last drought is the best predictor of the biovolume (or biomass) of enchytraeids. Moreover, species richness was significantly impacted by the average soil water content experienced by...... enchytraeids during the 8-year study. It seems, therefore, that the most important factor for enchytraeid abundance and species diversity in the projected future climate conditions is soil water content........ The warming treatment had a modest effect on soil temperatures (0.3 C at 5 cm depth) and did not have significant effect on abundance or biovolume of enchytraeids. However, the individual body size of Chamaedrilus chlorophilus (= Cognettia sphagnetorum partim.) was negatively correlated with soil...

  17. Arbuscular Mycorrhizal Fungi May Mitigate the Influence of a Joint Rise of Temperature and Atmospheric CO2 on Soil Respiration in Grasslands

    Directory of Open Access Journals (Sweden)

    S. Vicca

    2009-01-01

    Full Text Available We investigated the effects of mycorrhizal colonization and future climate on roots and soil respiration (Rsoil in model grassland ecosystems. We exposed artificial grassland communities on pasteurized soil (no living arbuscular mycorrhizal fungi (AMF present and on pasteurized soil subsequently inoculated with AMF to ambient conditions and to a combination of elevated CO2 and temperature (future climate scenario. After one growing season, the inoculated soil revealed a positive climate effect on AMF root colonization and this elicited a significant AMF x climate scenario interaction on root biomass. Whereas the future climate scenario tended to increase root biomass in the noninoculated soil, the inoculated soil revealed a 30% reduction of root biomass under warming at elevated CO2 (albeit not significant. This resulted in a diminished response of Rsoil to simulated climatic change, suggesting that AMF may contribute to an attenuated stimulation of Rsoil in a warmer, high CO2 world.

  18. Boreal lakes moderate seasonal and diurnal temperature variation and perturb atmospheric circulation: Analyses in the Community Earth System Model 1 (CESM1)

    Energy Technology Data Exchange (ETDEWEB)

    Subin, Zachary M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Div.; Murphy, Lisa N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Div.; Li, Fiyu [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Div.; Bonfils, Celine [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Program for Climate Model Diagnosis and Intercomparison; Riley, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Div.

    2012-01-15

    We used a lake thermal physics model recently coupled into the Community Earth System Model 1 (CESM1) to study the effects of lake distribution in present and future climate. Under present climate, correcting the large underestimation of lake area in CESM1 (denoted CCSM4 in the configuration used here) caused 1 °C spring decreases and fall increases in surface air temperature throughout large areas of Canada and the US. Simulated summer surface diurnal air temperature range decreased by up to 4 °C, reducing CCSM4 biases. These changes were much larger than those resulting from prescribed lake disappearance in some present-day permafrost regions under doubled-CO2 conditions. Correcting the underestimation of lake area in present climate caused widespread high-latitude summer cooling at 850 hPa. Significant remote changes included decreases in the strength of fall Southern Ocean westerlies. We found significantly different winter responses when separately analysing 45-yr subperiods, indicating that relatively long simulations are required to discern the impacts of surface changes on remote conditions. We also investigated the surface forcing of lakes using idealised aqua-planet experiments which showed that surface changes of 2 °C in the Northern Hemisphere extra-tropics could cause substantial changes in precipitation and winds in the tropics and Southern Hemisphere. Shifts in the Inter-Tropical Convergence Zone were opposite in sign to those predicted by some previous studies. Zonal mean circulation changes were consistent in character but much larger than those occurring in the lake distribution experiments, due to the larger magnitude and more uniform surface forcing in the idealised aqua-planet experiments.

  19. Boreal lakes moderate seasonal and diurnal temperature variation and perturb atmospheric circulation: analyses in the Community Earth System Model 1 (CESM1

    Directory of Open Access Journals (Sweden)

    William J. Riley

    2012-02-01

    Full Text Available We used a lake thermal physics model recently coupled into the Community Earth System Model 1 (CESM1 to study the effects of lake distribution in present and future climate. Under present climate, correcting the large underestimation of lake area in CESM1 (denoted CCSM4 in the configuration used here caused 1 °C spring decreases and fall increases in surface air temperature throughout large areas of Canada and the US. Simulated summer surface diurnal air temperature range decreased by up to 4 °C, reducing CCSM4 biases. These changes were much larger than those resulting from prescribed lake disappearance in some present-day permafrost regions under doubled-CO2 conditions. Correcting the underestimation of lake area in present climate caused widespread high-latitude summer cooling at 850 hPa. Significant remote changes included decreases in the strength of fall Southern Ocean westerlies. We found significantly different winter responses when separately analysing 45-yr subperiods, indicating that relatively long simulations are required to discern the impacts of surface changes on remote conditions. We also investigated the surface forcing of lakes using idealised aqua-planet experiments which showed that surface changes of 2 °C in the Northern Hemisphere extra-tropics could cause substantial changes in precipitation and winds in the tropics and Southern Hemisphere. Shifts in the Inter-Tropical Convergence Zone were opposite in sign to those predicted by some previous studies. Zonal mean circulation changes were consistent in character but much larger than those occurring in the lake distribution experiments, due to the larger magnitude and more uniform surface forcing in the idealised aqua-planet experiments.

  20. Densities and viscosities of binary mixtures of n-decane+1-pentanol,+1-hexanol,+1-heptanol at temperatures from 293.15 to 363.15 K and atmospheric pressure☆

    Institute of Scientific and Technical Information of China (English)

    Alejandro Estrada-Baltazar; Micael Gerardo Bravo-Sanchez; Gustavo Arturo Iglesias-Silva; Juan Francisco Javier Alvarado; Edgar Omar Castrejon-Gonzalez; Mariana Ramos-Estrada

    2015-01-01

    Densities (ρ) and dynamic viscosities (η) for three binary mixtures of n-decane with 1-pentanol, 1-hexanol and 1-heptanol are presented at temperatures from 293.15 to 363.15 K and atmospheric pressure over the entire composition range. The density and viscosity are measured using a vibrating tube densimeter and a cylindrical Couette type rotating viscometer, respectively. Excess molar volumes (VE), viscosity deviations (Δη) and excess Gibbs energy of activation of viscous flow (ΔG*E) are calculated from the experimental measurements. Intermo-lecular and structural interactions are indicated by the sign and magnitude of these properties. Partial molar vol-umes and infinity dilution molar partial volumes are also calculated for each binary system. These results are correlated using Redlich–Kister type equations.