WorldWideScience

Sample records for water vapor s-t

  1. Water vaporization on Ceres

    Science.gov (United States)

    A'Hearn, Michael F.; Feldman, Paul D.

    1992-01-01

    A search is presently conducted for OH generated by the photodissociation of atmospheric water vapor in long-exposure IUE spectra of the region around Ceres. A statistically significant detection of OH is noted in an exposure off the northern limb of Ceres after perihelion. The amount of OH is consistent with a polar cap that might be replenished during winter by subsurface percolation, but which dissipates in summer.

  2. Water vapor adsorption on goethite.

    Science.gov (United States)

    Song, Xiaowei; Boily, Jean-François

    2013-07-02

    Goethite (α-FeOOH) is an important mineral contributing to processes of atmospheric and terrestrial importance. Their interactions with water vapor are particularly relevant in these contexts. In this work, molecular details of water vapor (0.0-19.0 Torr; 0-96% relative humidity at 25 °C) adsorption at surfaces of synthetic goethite nanoparticles reacted with and without HCl and NaCl were resolved using vibrational spectroscopy. This technique probed interactions between surface (hydr)oxo groups and liquid water-like films. Molecular dynamics showed that structures and orientations adopted by these waters are comparable to those adopted at the interface with liquid water. Particle surfaces reacted with HCl accumulated less water than acid-free surfaces due to disruptions in hydrogen bond networks by chemisorbed waters and chloride. Particles reacted with NaCl had lower loadings below ∼10 Torr water vapor but greater loadings above this value than salt-free surfaces. Water adsorption reactions were here affected by competitive hydration of coexisting salt-free surface regions, adsorbed chloride and sodium, as well as precipitated NaCl. Collectively, the findings presented in this study add further insight into the initial mechanisms of thin water film formation at goethite surfaces subjected to variations in water vapor pressure that are relevant to natural systems.

  3. Importance Profiles for Water Vapor

    Science.gov (United States)

    Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita

    2017-10-01

    Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or "kernel" depends on whether specific humidity S, relative humidity R, or ln(R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

  4. Importance Profiles for Water Vapor

    Science.gov (United States)

    Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita

    2017-11-01

    Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or "kernel" depends on whether specific humidity S, relative humidity R, or ln( R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

  5. Water Vapor Permeation in Plastics

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Paul E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-01-01

    Polyvinyl toluene (PVT) and polystyrene (PS) (referred to as “plastic scintillator”) are used for gamma ray detectors. A significant decrease in radiation detection performance has been observed in some PVT-based gamma-ray detectors in systems in outdoor environments as they age. Recent studies have revealed that plastic scintillator can undergo an environmentally related material degradation that adversely affects gamma ray detection performance under certain conditions and histories. A significant decrease in sensitivity has been seen in some gamma-ray detectors in some systems as they age. The degradation of sensitivity of plastic scintillator over time is due to a variety of factors, and the term “aging” is used to encompass all factors. Some plastic scintillator samples show no aging effects (no significant change in sensitivity over more than 10 years), while others show severe aging (significant change in sensitivity in less than 5 years). Aging effects arise from weather (variations in heat and humidity), chemical exposure, mechanical stress, light exposure, and loss of volatile components. The damage produced by these various causes can be cumulative, causing observable damage to increase over time. Damage may be reversible up to some point, but becomes permanent under some conditions. The objective of this report is to document the phenomenon of permeability of plastic scintillator to water vapor and to derive the relationship between time, temperature, humidity and degree of water penetration in plastic. Several conclusions are documented about the properties of water permeability of plastic scintillator.

  6. Mars water vapor, near-surface

    Science.gov (United States)

    Ryan, J. A.; Sharman, R. D.; Lucich, R. D.

    1982-01-01

    In a previous paper we concluded that the temperature sensors aboard the Viking landers (VL-1 and VL-2) were detecting the water vapor frost point. Analysis of one Mars year of data at both lander sites substantiates this conclusion. At VL-1 it is found that the water vapor mixing ratio is constant with height through the bulk of the atmosphere, most of the time. Exceptions are during the onset phases of the two major dust storms when temporary enhancement of near-surface vapor occurs (the same phenomenon is observed at VL-2), and some depletion of near-surface vapor during the decay phase of the first storm, possibly the second storm as well. The former suggests near-surface, northward transport of water vapor with the storms. The latter suggests adsorption of vapor on dust particles followed by surface deposition. At VL-2, severe near-surface depletion of water vapor occurs during northern autumn and winter. The residual vapor is in equilibrium with the surface condensate observed at the site during this period, indicating that the source region for the condensate must be aloft with downward transport by dust fall-out. Since the near-surface water vapor mixing ratio and concentration at VL-1 generally parallels the column abundance over VL-1 obtained by the orbiters, this suggests that VL-1 can be used to give a measure of column abundance for as long as the temperature sensors remain operational.

  7. DMSP SSMT/2 - Atmospheric Water Vapor Profiler

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/T-2 sensor is a five channel, total power microwave radiometer with three channels situated symmetrically about the 183.31 GHz water vapor resonance line and...

  8. Water Vapor Corrosion in EBC Constituent Materials

    Science.gov (United States)

    Kowalski, Benjamin; Fox, Dennis; Jacobson, Nathan S.

    2017-01-01

    Environmental Barrier Coating (EBC) materials are sought after to protect ceramic matrix composites (CMC) in high temperature turbine engines. CMCs are particularly susceptible to degradation from oxidation, Ca-Al-Mg-Silicate (CMAS), and water vapor during high temperature operation which necessitates the use of EBCs. However, the work presented here focuses on water vapor induced recession in EBC constituent materials. For example, in the presence of water vapor, silica will react to form Si(OH)4 (g) which will eventually corrode the material away. To investigate the recession rate in EBC constituent materials under high temperature water vapor conditions, thermal gravimetric analysis (TGA) is employed. The degradation process can then be modeled through a simple boundary layer expression. Ultimately, comparisons are made between various single- and poly-crystalline materials (e.g. TiO2, SiO2) against those found in literature.

  9. GOES WATER VAPOR TRANSPORT V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOES Water Vapor Transport CD contains nineteen months of geostationary satellite-derived products from the GOES-8 satellite spanning the 1987-1988 El Nino...

  10. Arctic Water Vapor Characteristics from Rawinsondes

    Data.gov (United States)

    National Aeronautics and Space Administration — A gridded climatological monthly-mean data base of Arctic water vapor characteristics has been assembled by combining fixed station data with data from soundings...

  11. Optical monitor for water vapor concentration

    Science.gov (United States)

    Kebabian, Paul

    1998-01-01

    A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma.

  12. The vertical distribution of Mars water vapor

    Science.gov (United States)

    Davies, D. W.

    1979-01-01

    Analysis of observations made from the Viking 1 Orbiter indicates that the water vapor over the Viking 1 landing site is uniformly mixed with the atmosphere and not concentrated near the surface. The analysis incorporates the effects of atmospheric scattering and explains why previous earth-based observations showed a strong diurnal variation in water content. It also explains the lack of an early morning fog and removes the necessity of daily exchange of large amounts of water between the surface and the atmosphere. A water vapor volume mixing ratio of 1.5 x 10 to the -4th is inferred for the Viking 1 site in late summer.

  13. Refraction of microwave signals by water vapor

    Science.gov (United States)

    Goldfinger, A. D.

    1980-01-01

    Tropospheric water vapor causes a refractive path length effect which is typically 5-10% of the 'dry' tropospheric effect and as large as several meters at elevation angles below 5 deg. The vertical water vapor profile is quite variable, and measurements of intensive atmospheric parameters such as temperature and humidity limited to the surface do not adequately predict the refractive effect. It is suggested that a water vapor refraction model that is a function of the amount of precipitable water alone can be successful at low elevation angles. From an extensive study of numerical ray tracings through radiosonde balloon data, such a model has been constructed. The model predicts the effect at all latitudes and elevation angles between 2 and 10 deg to an accuracy of better than 4% (11 cm at 3 deg elevation angle).

  14. Dynamic water vapor and temperature calibration system.

    Science.gov (United States)

    Montague, F W; Primiano, F P; Saidel, G M

    1984-06-01

    The objective evaluation of thermal and humidification processes in the pulmonary system requires accurate dynamic measurements of temperature and water vapor concentration of a flowing gas mixture. The adequacy of instruments used for such measurements can only be determined by dynamic calibration techniques. We have developed a method of producing step changes in temperature and water vapor content of a gas mixture undergoing controlled steady flow. The system consists of two reservoirs and a slide valve that switches a test section between them. The inlet (usually a probe or catheter tip) of the device to be calibrated is positioned in the test section. The flow rate through the test section is minimally changed during the transition between gas from one reservoir to that of the other. The system has been used to analyze the response of a thermistor and a respiratory mass spectrometer to changes in gas temperature and water vapor.

  15. Water vapor movement in freezing aggregate base materials.

    Science.gov (United States)

    2014-06-01

    The objectives of this research were to 1) measure the extent to which water vapor movement results in : water accumulation in freezing base materials; 2) evaluate the effect of soil stabilization on water vapor movement : in freezing base materials;...

  16. Vaporization of fault water during seismic slip

    Science.gov (United States)

    Chen, Jianye; Niemeijer, André R.; Fokker, Peter A.

    2017-06-01

    Laboratory and numerical studies, as well as field observations, indicate that phase transitions of pore water might be an important process in large earthquakes. We present a model of the thermo-hydro-chemo-mechanical processes, including a two-phase mixture model to incorporate the phase transitions of pore water, occurring during fast slip (i.e., a natural earthquake) in order to investigate the effects of vaporization on the coseismic slip. Using parameters from typical natural faults, our modeling shows that vaporization can indeed occur at the shallow depths of an earthquake, irrespective of the wide variability of the parameters involved (sliding velocity, friction coefficient, gouge permeability and porosity, and shear-induced dilatancy). Due to the fast kinetics, water vaporization can cause a rapid slip weakening even when the hydrological conditions of the fault zone are not favorable for thermal pressurization, e.g., when permeability is high. At the same time, the latent heat associated with the phase transition causes the temperature rise in the slip zone to be buffered. Our parametric analyses reveal that the amount of frictional work is the principal factor controlling the onset and activity of vaporization and that it can easily be achieved in earthquakes. Our study shows that coseismic pore fluid vaporization might have played important roles at shallow depths of large earthquakes by enhancing slip weakening and buffering the temperature rise. The combined effects may provide an alternative explanation for the fact that low-temperature anomalies were measured in the slip zones at shallow depths of large earthquakes.

  17. Quality and Control of Water Vapor Winds

    Science.gov (United States)

    Jedlovec, Gary J.; Atkinson, Robert J.

    1996-01-01

    Water vapor imagery from the geostationary satellites such as GOES, Meteosat, and GMS provides synoptic views of dynamical events on a continual basis. Because the imagery represents a non-linear combination of mid- and upper-tropospheric thermodynamic parameters (three-dimensional variations in temperature and humidity), video loops of these image products provide enlightening views of regional flow fields, the movement of tropical and extratropical storm systems, the transfer of moisture between hemispheres and from the tropics to the mid- latitudes, and the dominance of high pressure systems over particular regions of the Earth. Despite the obvious larger scale features, the water vapor imagery contains significant image variability down to the single 8 km GOES pixel. These features can be quantitatively identified and tracked from one time to the next using various image processing techniques. Merrill et al. (1991), Hayden and Schmidt (1992), and Laurent (1993) have documented the operational procedures and capabilities of NOAA and ESOC to produce cloud and water vapor winds. These techniques employ standard correlation and template matching approaches to wind tracking and use qualitative and quantitative procedures to eliminate bad wind vectors from the wind data set. Techniques have also been developed to improve the quality of the operational winds though robust editing procedures (Hayden and Veldon 1991). These quality and control approaches have limitations, are often subjective, and constrain wind variability to be consistent with model derived wind fields. This paper describes research focused on the refinement of objective quality and control parameters for water vapor wind vector data sets. New quality and control measures are developed and employed to provide a more robust wind data set for climate analysis, data assimilation studies, as well as operational weather forecasting. The parameters are applicable to cloud-tracked winds as well with minor

  18. Characterization of a Compact Water Vapor Radiometer

    Science.gov (United States)

    Gill, Ajay; Selina, Rob

    2018-01-01

    We report on laboratory test results of the Compact Water Vapor Radiometer (CWVR) prototype for the Karl G. Jansky Very Large Array (VLA), a five-channel design centered around the 22 GHz water vapor line. Fluctuations in perceptible water vapor cause fluctuations in atmospheric brightness emission, which are assumed to be proportional to phase fluctuations of the astronomical signal seen by an antenna. The design is intended to support empirical radiometric phase corrections for each baseline in the array.The dynamic range, channel isolation, and gain stability of the device were characterized. The device has a useful dynamic range of order 18 dB after calibration, and the CWVR channel isolation requirement of 102.6 sec. With temperature corrections, the single channel and channel difference gain stability per channel is < 2 x 10-4 over τ = 2.5 - 103 sec, which meets the < 2 x 10-4 requirement. The observable gain stability is < 2.5 x 10-4 over τ = 2.5 - 103 sec, which meets the < 2.5 x 10-4 requirement.Overall, the test results indicate that the CWVR meets required specifications for dynamic range, channel isolation, and gain stability in order to proceed with testing on a pair of VLA antennas.

  19. Permeability of MDT chambers to water vapor

    CERN Document Server

    Palestini, S

    2003-01-01

    Tests of MDT chambers performed at the GIF facility and in the H8 test-beam area have shown relative high levels of water vapor contamination in the gas-mixture at the detector output. This effects significantly the drift properties of the MDTs. This note shows that amount of water observed is compatible with approximate estimates based on the permeability of Noryl, used in the tube end-plugs, and of EPDM, used in the O-rings of the on-chamber gas distribution.

  20. Water Vapor Effects on Silica-Forming Ceramics

    Science.gov (United States)

    Opila, E. J.; Greenbauer-Seng, L. (Technical Monitor)

    2000-01-01

    Silica-forming ceramics such as SiC and Si3N4 are proposed for applications in combustion environments. These environments contain water vapor as a product of combustion. Oxidation of silica-formers is more rapid in water vapor than in oxygen. Parabolic oxidation rates increase with the water vapor partial pressure with a power law exponent value close to one. Molecular water vapor is therefore the mobile species in silica. Rapid oxidation rates and large amounts of gases generated during the oxidation reaction in high water vapor pressures may result in bubble formation in the silica and nonprotective scale formation. It is also shown that silica reacts with water vapor to form Si(OH)4(g). Silica volatility has been modeled using a laminar flow boundary layer controlled reaction equation. Silica volatility depends on the partial pressure of water vapor, the total pressure, and the gas velocity. Simultaneous oxidation and volatilization reactions have been modeled with paralinear kinetics.

  1. Lunar absorption spectrophotometer for measuring atmospheric water vapor.

    Science.gov (United States)

    Querel, Richard R; Naylor, David A

    2011-02-01

    A novel instrument has been designed to measure the nighttime atmospheric water vapor column abundance by near-infrared absorption spectrophotometry of the Moon. The instrument provides a simple, effective, portable, and inexpensive means of rapidly measuring the water vapor content along the lunar line of sight. Moreover, the instrument is relatively insensitive to the atmospheric model used and, thus, serves to provide an independent calibration for other measures of precipitable water vapor from both ground- and space-based platforms.

  2. Application of Hotelling’s T{sup 2} charts in monitoring quality parameters in a drinking water supply system

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Mafalda T., E-mail: mafaldatcosta@gmail.com [UAberta, Portugal and Ministry of Economy, Portuguese Government (Canada); Carolino, Elisabete, E-mail: lizcarolino@gmail.com [ESTeSL-IPL, Research Group Environment and Health of ESTeSL-IPL (Portugal); Oliveira, Teresa A., E-mail: teresa.oliveira@uab.pt [DCeT - Universidade Aberta, and Center of Statistics and Applications of University of Lisbon (Portugal)

    2015-03-10

    In water supply systems with distribution networkthe most critical aspects of control and Monitoring of water quality, which generates crises system, are the effects of cross-contamination originated by the network typology. The classics of control of quality systems through the application of Shewhart charts are generally difficult to manage in real time due to the high number of charts that must be completed and evaluated. As an alternative to the traditional control systems with Shewhart charts, this study aimed to apply a simplified methodology of a monitoring plan quality parameters in a drinking water distribution, by applying Hotelling’s T{sup 2} charts and supplemented with Shewhart charts with Bonferroni limits system, whenever instabilities with processes were detected.

  3. Water vapor sorption hysteresis of ceramic bricks

    Science.gov (United States)

    Koronthalyova, Olga

    2016-07-01

    A quantification of the hysteretic effects and their thorough analysis was carried out for three types of ceramic bricks. Water vapor adsorption/desorption isotherms were measured by the standard desiccator method. The desorption measurements were carried out from capillary moisture content as well as from equilibrium moisture content corresponding to the relative humidity of 98 %. For all three tested types of bricks the hysteretic effects were present but their significance differed depending on the particular type of brick. Significant differences were noticed also in desorption curves determined from capillary moisture content and from equilibrium moisture content corresponding to the relative humidity of 98 %. Based on the measured data a possible correlation between pore structure parameters and noticed hysteretic effects as well as relevance of the open pore model are discussed. The obtained adsorption/desorption curves were approximated by an analytical relation.

  4. Water recovery by catalytic treatment of urine vapor

    Science.gov (United States)

    Budininkas, P.; Quattrone, P. D.; Leban, M. I.

    1980-01-01

    The objective of this investigation was to demonstrate the feasibility of water recovery on a man-rated scale by the catalytic processing of untreated urine vapor. For this purpose, two catalytic systems, one capable of processing an air stream containing low urine vapor concentrations and another to process streams with high urine vapor concentrations, were designed, constructed, and tested to establish the quality of the recovered water.

  5. Operating a radio-frequency plasma source on water vapor.

    Science.gov (United States)

    Nguyen, Sonca V T; Foster, John E; Gallimore, Alec D

    2009-08-01

    A magnetically enhanced radio-frequency (rf) plasma source operating on water vapor has an extensive list of potential applications. In this work, the use of a rf plasma source to dissociate water vapor for hydrogen production is investigated. This paper describes a rf plasma source operated on water vapor and characterizes its plasma properties using a Langmuir probe, a residual gas analyzer, and a spectrometer. The plasma source operated first on argon and then on water vapor at operating pressures just over 300 mtorr. Argon and water vapor plasma number densities differ significantly. In the electropositive argon plasma, quasineutrality requires n(i) approximately = n(e), where n(i) is the positive ion density. But in the electronegative water plasma, quasineutrality requires n(i+) = n(i-) + n(e). The positive ion density and electron density of the water vapor plasma are approximately one and two orders of magnitude lower, respectively, than those of argon plasma. These results suggest that attachment and dissociative attachment are present in electronegative water vapor plasma. The electron temperature for this water vapor plasma source is between 1.5 and 4 eV. Without an applied axial magnetic field, hydrogen production increases linearly with rf power. With an axial magnetic field, hydrogen production jumps to a maximum value at 500 W and then saturates with rf power. The presence of the applied axial magnetic field is therefore shown to enhance hydrogen production.

  6. Water vapor and Gas Transport through Polymeric Membranes

    NARCIS (Netherlands)

    Metz, S.J.

    2003-01-01

    Water vapor transport through polymeric materials plays an important role in a large number of applications such as: food packaging, breathable clothing, roofing membranes, diapers, and the removal of water vapor from gas streams (e.g. dehydration of natural gas or the drying of compressed air).

  7. Water Vapor in the Protoplanetary Disk of DG Tau

    NARCIS (Netherlands)

    Podio, L.; Kamp, I.; Codella, C.; Cabrit, S.; Nisini, B.; Dougados, C.; Sandell, G.; Williams, J. P.; Testi, L.; Thi, W. -F.; Woitke, P.; Meijerink, R.; Spaans, M.; Aresu, G.; Menard, F.; Pinte, C.

    2013-01-01

    Water is key in the evolution of protoplanetary disks and the formation of comets and icy/water planets. While high-excitation water lines originating in the hot inner disk have been detected in several T Tauri stars (TTSs), water vapor from the outer disk, where most water ice reservoirs are

  8. Adsorption and Desorption of Nitrogen and Water Vapor by clay

    Science.gov (United States)

    Cui, Deshan; Chen, Qiong; Xiang, Wei; Huang, Wei

    2015-04-01

    Adsorption and desorption of nitrogen and water vapor by clay has a significant impact on unsaturated soil physical and mechanical properties. In order to study the adsorption and desorption characteristics of nitrogen and water vapor by montmorillonite, kaolin and sliding zone soils, the Autosorb-iQ specific surface area and pore size analyzer instrument of United State was taken to carry out the analysis test. The adsorption and desorption of nitrogen at 77K and water vapor at 293K on clay sample were conducted. The theories of BET, FHH and hydration energy were taken to calculate the specific surface, surface fractal dimension and adsorption energy. The results show that the calculated specific surface of water vapor by clay is bigger than nitrogen adsorption test because clay can adsorb more water vapor molecule than nitrogen. Smaller and polar water vapor molecule can access the micropore and then adsorb on the mineral surface and mineral intralayer, which make the mineral surface cations hydrate and the mineral surface smoother. Bigger and nonpolar nitrogen molecule can not enter into the micropore as water vapor molecule and has weak interaction with clay surface.

  9. Regolith water vapor sources on Mars: A historical bibliography

    Science.gov (United States)

    Clifford, Stephen M.; Huguenin, R. L.

    1988-01-01

    The regolith as a potential source and sink of atmospheric water is examined bibliographically. The controversy surrounding Solis Lacus, a region on Mars first identified by R. Huguenin as a possible regolith source of atmospheric water vapor, is reviewed. The publications listed describe the initial debate over the existence of a regolith source of atmospheric water vapor in Solis Lacus. The debate over Solis Lacus has motivated a rigorous examination of several important data sets, and helped define the limits of their interpretation.

  10. Isobaric vapor-liquid equilibria of water + ethanol + hexyl acetate

    Energy Technology Data Exchange (ETDEWEB)

    Arce, A.; Soto, A. [Univ. of Santiago de Compostela (Spain). Chemical Engineering Dept.; Orge, B.; Tojo, J. [Univ. of Vigo (Spain). Chemical Engineering Dept.

    1995-09-01

    The authors determined the isobaric vapor-liquid equilibrium data for the ternary system water + ethanol + hexyl acetate at 101.325 kPa using a distillation apparatus recycling both liquid and vapor phases. The results were compared with those predicted using group contribution methods. The UNIFAC method gave the best predictions.

  11. Mars: Water Vapor Observations from the Viking Orbiters

    Science.gov (United States)

    Farmer, C. B.; Davies, D. W.; Holland, A. L.; Laporte, D. D.; Doms, P. E.

    1977-01-01

    The global distribution of the water vapor has been mapped at low resolution throughout the period from the northern summer solstice to the following equinox. During this seasonal period the water vapor underwent a gradual redistribution, the latitude of maximum column abundance moving from the northern polar area to the equatorial latitudes. The total global vapor content remained approximately constant at the equivalent of about 1.3 cu km of ice. The various data obtained indicate that the residual polar caps are composed of water ice.

  12. Static Water Vapor Feed Electrolyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a static vapor feed electrolyzer utilizing an advanced bipolar plate that produces sub-saturated H2 and O2 is proposed. This novel bipolar design can...

  13. Urban emissions of water vapor in winter

    Science.gov (United States)

    Salmon, Olivia E.; Shepson, Paul B.; Ren, Xinrong; Marquardt Collow, Allison B.; Miller, Mark A.; Carlton, Annmarie G.; Cambaliza, Maria O. L.; Heimburger, Alexie; Morgan, Kristan L.; Fuentes, Jose D.; Stirm, Brian H.; Grundman, Robert; Dickerson, Russell R.

    2017-09-01

    Elevated water vapor (H2Ov) mole fractions were occasionally observed downwind of Indianapolis, IN, and the Washington, D.C.-Baltimore, MD, area during airborne mass balance experiments conducted during winter months between 2012 and 2015. On days when an urban H2Ov excess signal was observed, H2Ov emission estimates range between 1.6 × 104 and 1.7 × 105 kg s-1 and account for up to 8.4% of the total (background + urban excess) advected flow of atmospheric boundary layer H2Ov from the urban study sites. Estimates of H2Ov emissions from combustion sources and electricity generation facility cooling towers are 1-2 orders of magnitude smaller than the urban H2Ov emission rates estimated from observations. Instances of urban H2Ov enhancement could be a result of differences in snowmelt and evaporation rates within the urban area, due in part to larger wintertime anthropogenic heat flux and land cover differences, relative to surrounding rural areas. More study is needed to understand why the urban H2Ov excess signal is observed on some days, and not others. Radiative transfer modeling indicates that the observed urban enhancements in H2Ov and other greenhouse gas mole fractions contribute only 0.1°C d-1 to the urban heat island at the surface. This integrated warming through the boundary layer is offset by longwave cooling by H2Ov at the top of the boundary layer. While the radiative impacts of urban H2Ov emissions do not meaningfully influence urban heat island intensity, urban H2Ov emissions may have the potential to alter downwind aerosol and cloud properties.

  14. Effect of Precipitable Water Vapor Amount on Radiative Cooling Performance

    Science.gov (United States)

    Hu, Mingke; Zhao, Bin; Ao, Xianze; Pei, Gang

    2017-05-01

    A radiative cooler based on aluminum-evaporated polyvinyl-fluoride surface was employed to investigate the effect of precipitable water vapor amount on its radiative cooling performance. A mathematic model of steady heat transfer that considers the spectral radiant distribution of the sky, the transparent cover and the collecting surface was established. The results indicate that the amount of precipitable water vapor shows a remarkable and negative effect on radiative cooling performance of the radiative cooler. Both the temperature difference between the cooler and surroundings and the net radiative cooling power decrease as the precipitable water vapor amount increases. The net radiative cooling power drops by about 41.0% as the the precipitable water vapor amount changes from 1.0 cm to 7.0 cm. Besides, the radiative cooler shows better cooling performance in winter than in summer. The net radiative cooling power in summer of Hefei is about 82.2% of that in winter.

  15. CRISM Observations of Water Vapor and Carbon Monoxide

    Science.gov (United States)

    Smith, Michael D.; Wolff, Michael J.; Clancy, R. Todd

    2008-01-01

    Near-infrared spectra returned by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM, [1]) on-board the Mars Reconnaissance Orbiter (MRO) contain the clear spectral signature of several atmospheric gases including carbon dioxide (CO2), water vapor (H2O), and carbon monoxide (CO). Here we describe the seasonal and spatial mapping of water vapor and carbon dioxide for one full Martian year using CRISM spectra.

  16. Logarithmic radiative effect of water vapor and spectral kernels

    Science.gov (United States)

    Bani Shahabadi, Maziar; Huang, Yi

    2014-05-01

    Radiative kernels have become a useful tool in climate analysis. A set of spectral kernels is calculated using a moderate resolution atmospheric transmission code MODTRAN and implemented in diagnosing spectrally decomposed global outgoing longwave radiation (OLR) changes. It is found that the effect of water vapor on the OLR is in proportion to the logarithm of its concentration. Spectral analysis discloses that this logarithmic dependency mainly results from water vapor absorption bands (0-560 cm-1 and 1250-1850 cm-1), while in the window region (800-1250 cm-1), the effect scales more linearly to its concentration. The logarithmic and linear effects in the respective spectral regions are validated by the calculations of a benchmark line-by-line radiative transfer model LBLRTM. The analysis based on LBLRTM-calculated second-order kernels shows that the nonlinear (logarithmic) effect results from the damping of the OLR sensitivity to layer-wise water vapor perturbation by both intra- and inter-layer effects. Given that different scaling approaches suit different spectral regions, it is advisable to apply the kernels in a hybrid manner in diagnosing the water vapor radiative effect. Applying logarithmic scaling in the water vapor absorption bands where absorption is strong and linear scaling in the window region where absorption is weak can generally constrain the error to within 10% of the overall OLR change for up to eightfold water vapor perturbations.

  17. In-Situ Water Vapor Probe for a Robot Arm-Mounted, Compact Water Vapor Analyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to test a prototype water vapor sampling end-effector in the laboratory and in the field thatwill eventually be integrated with a small, infrared...

  18. Rapid and fully automated Measurement of Water Vapor Sorption Isotherms

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Møldrup, Per

    2014-01-01

    Eminent environmental challenges such as remediation of contaminated sites, the establishment and maintenance of nuclear waste repositories, or the design of surface landfill covers all require accurate quantification of the soil water characteristic at low water contents. Furthermore, several...... and pesticide volatilization, toxic organic vapor sorption kinetics, and soil water repellency are illustrated. Several methods to quantify hysteresis effects and to derive soil clay content and specific surface area from VSA-measured isotherms are presented. Besides above mentioned applications, potential...... essential but difficult-to-measure soil properties such as clay content and specific surface area are intimately related to water vapor sorption. Until recently, it was a major challenge to accurately measure detailed water vapor sorption isotherms within an acceptable time frame. This priority...

  19. Applying the Water Vapor Radiometer to Verify the Precipitable Water Vapor Measured by GPS

    Directory of Open Access Journals (Sweden)

    Ta-Kang Yeh

    2014-01-01

    Full Text Available Taiwan is located at the land-sea interface in a subtropical region. Because the climate is warm and moist year round, there is a large and highly variable amount of water vapor in the atmosphere. In this study, we calculated the Zenith Wet Delay (ZWD of the troposphere using the ground-based Global Positioning System (GPS. The ZWD measured by two Water Vapor Radiometers (WVRs was then used to verify the ZWD that had been calculated using GPS. We also analyzed the correlation between the ZWD and the precipitation data of these two types of station. Moreover, we used the observational data from 14 GPS and rainfall stations to evaluate three cases. The offset between the GPS-ZWD and the WVR-ZWD ranged from 1.31 to 2.57 cm. The correlation coefficient ranged from 0.89 to 0.93. The results calculated from GPS and those measured using the WVR were very similar. Moreover, when there was no rain, light rain, moderate rain, or heavy rain, the flatland station ZWD was 0.31, 0.36, 0.38, or 0.40 m, respectively. The mountain station ZWD exhibited the same trend. Therefore, these results have demonstrated that the potential and strength of precipitation in a region can be estimated according to its ZWD values. Now that the precision of GPS-ZWD has been confirmed, this method can eventually be expanded to the more than 400 GPS stations in Taiwan and its surrounding islands. The near real-time ZWD data with improved spatial and temporal resolution can be provided to the city and countryside weather-forecasting system that is currently under development. Such an exchange would fundamentally improve the resources used to generate weather forecasts.

  20. Daytime Raman lidar for water vapor and ozone concentration measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Duk Hyeon; Cha, Hyung Ki; Lee, Jong Min [Laboratory for QuantumOptics, Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of); Veselovskii, I. [Physcis Instrumentation Center of General Physcis Institute, Moscow (Russian Federation)

    1996-11-15

    A Raman lidar system based on a quadrupled Nd : Yagi laser monitors the Raman signals from N{sub 2}, O{sub 2} and H{sub 2}O molecules. To suppress the elastic backscatter, a specially designed liquid absorption edge filter is used. The water vapor concentration is calculated from the radio of water and nitrogen Raman signals. Ozone concentration is evaluated from nitrogen and oxygen Raman returns by applying Dial technique. The obtained ozone profiles can be used for water vapor data correction.

  1. Water vapor estimation using digital terrestrial broadcasting waves

    Science.gov (United States)

    Kawamura, S.; Ohta, H.; Hanado, H.; Yamamoto, M. K.; Shiga, N.; Kido, K.; Yasuda, S.; Goto, T.; Ichikawa, R.; Amagai, J.; Imamura, K.; Fujieda, M.; Iwai, H.; Sugitani, S.; Iguchi, T.

    2017-03-01

    A method of estimating water vapor (propagation delay due to water vapor) using digital terrestrial broadcasting waves is proposed. Our target is to improve the accuracy of numerical weather forecast for severe weather phenomena such as localized heavy rainstorms in urban areas through data assimilation. In this method, we estimate water vapor near a ground surface from the propagation delay of digital terrestrial broadcasting waves. A real-time delay measurement system with a software-defined radio technique is developed and tested. The data obtained using digital terrestrial broadcasting waves show good agreement with those obtained by ground-based meteorological observation. The main features of this observation are, no need for transmitters (receiving only), applicable wherever digital terrestrial broadcasting is available and its high time resolution. This study shows a possibility to estimate water vapor using digital terrestrial broadcasting waves. In the future, we will investigate the impact of these data toward numerical weather forecast through data assimilation. Developing a system that monitors water vapor near the ground surface with time and space resolutions of 30 s and several kilometers would improve the accuracy of the numerical weather forecast of localized severe weather phenomena.

  2. CONDENSATION OF WATER VAPOR IN A VERTICAL TUBE CONDENSER

    Directory of Open Access Journals (Sweden)

    Jan Havlík

    2015-10-01

    Full Text Available This paper presents an analysis of heat transfer in the process of condensation of water vapor in a vertical shell-and-tube condenser. We analyze the use of the Nusselt model for calculating the condensation heat transfer coefficient (HTC inside a vertical tube and the Kern, Bell-Delaware and Stream-flow analysis methods for calculating the shell-side HTC from tubes to cooling water. These methods are experimentally verified for a specific condenser of waste process vapor containing air. The operating conditions of the condenser may be different from the assumptions adopted in the basic Nusselt theory. Modifications to the Nusselt condensation model are theoretically analyzed.

  3. Profiles of electrostatic potential across the water-vapor, ice-vapor and ice-water interfaces

    Directory of Open Access Journals (Sweden)

    T. Bryk

    2016-02-01

    Full Text Available Ice-water, water-vapor interfaces and ice surface are studied by molecular dynamics simulations with the SPC/E model of water molecules having the purpose to estimate the profiles of electrostatic potential across the interfaces. We have proposed a methodology for calculating the profiles of electrostatic potential based on a trial particle, which showed good agreement for the case of electrostatic potential profile of the water-vapor interface of TIP4P model calculated in another way. The measured profile of electrostatic potential for the pure ice-water interface decreases towards the liquid bulk region, which is in agreement with simulations of preferential direction of motion of Li^{+} and F^{-} solute ions at the liquid side of the ice-water interface. These results are discussed in connection with the Workman-Reynolds effect.

  4. Water vapor pressure versus environmental lapse rate near the tropopause

    Science.gov (United States)

    Ferreira, Antonio; Castanheira, Jose; Gimeno, Luis

    2010-05-01

    The relationship between water vapor pressure and temperature lapse rate in the vicinity of the tropopause was investigated using in situ observations. The water vapor partial pressures and the lapse rates within a vertical distance of ±1.5 km around the first thermal tropopause were calculated from the vertical soundings conducted by the NOAA/CMDL at several locations in the last few decades (GMD Data Archive). A positive non-linear relationship between the two quantities was found to hold across the studied tropopause region at mid-latitudes and polar latitudes. A similar analysis was performed on the 300 and 250 hPa pressure levels (which often intercept the tropopause region), by collecting temperature and humidity observations within 1979-2008 from the Integrated Global Radiosonde Archive (IGRA). A relationship having almost the same shape was detected for statically stable lapse rates at all latitude zones. Given the relevance of water vapor in the radiative transfer in the upper troposphere, the results are an indication of a local influence of water vapor on the thermal structure of the transition layer between the troposphere and stratosphere

  5. Visualization of Atmospheric Water Vapor Data for SAGE

    Science.gov (United States)

    Kung, Mou-Liang; Chu, W. P. (Technical Monitor)

    2000-01-01

    The goal of this project was to develop visualization tools to study the water vapor dynamics using the Stratospheric Aerosol and Gas Experiment 11 (SAGE 11) water vapor data. During the past years, we completed the development of a visualization tool called EZSAGE, and various Gridded Water Vapor plots, tools deployed on the web to provide users with new insight into the water vapor dynamics. Results and experiences from this project, including papers, tutorials and reviews were published on the main Web page. Additional publishing effort has been initiated to package EZSAGE software for CD production and distribution. There have been some major personnel changes since Fall, 1998. Dr. Mou-Liang Kung, a Professor of Computer Science assumed the PI position vacated by Dr. Waldo Rodriguez who was on leave. However, former PI, Dr. Rodriguez continued to serve as a research adviser to this project to assure smooth transition and project completion. Typically in each semester, five student research assistants were hired and trained. Weekly group meetings were held to discuss problems, progress, new research direction, and activity planning. Other small group meetings were also held regularly for different objectives of this project. All student research assistants were required to submit reports for conference submission.

  6. The interaction of the theophylline metastable phase with water vapor

    Science.gov (United States)

    Matvienko, A. A.; Boldyrev, V. V.; Sidel'Nikov, A. A.; Chizhik, S. A.

    2008-07-01

    The conditions of hydration of the stable and metastable theophylline phases were determined. Two-phase metastable phase/monohydrate and stable phase/monohydrate equilibrium pressures were measured at 25, 30, and 35°C. The metastable phase began to react with water vapor at lower relative humidities than the stable phase. Processes that occurred with the metastable and stable theophylline phases over various water pressure ranges were considered. The metastable phase exhibited an unusual behavior at 25°C and relative humidity 47%. At constant water vapor pressure and temperature, theophylline was initially hydrated and then lost water and again became anhydrous. Two consecutive processes occurred in the system, the formation of theophylline monohydrate from the metastable phase and its decomposition to the stable phase. The ratio between the rates of these processes determined the content of the monohydrate at the given time moment.

  7. LBA-ECO CD-02 Oxygen Isotopes of Plant Tissue Water and Atmospheric Water Vapor

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports the oxygen isotope signatures of water extracted from plant tissue (xylem from the stems and leaf tissue) and of atmospheric water vapor from...

  8. Diurnal variations in water vapor over Central and South America

    Science.gov (United States)

    Meza, Amalia; Mendoza, Luciano; Bianchi, Clara

    2016-07-01

    Diurnal variations in atmospheric integrated water vapor (IWV) are studied employing IWV estimates, with a 30 minutes sampling rate, derived from Global Navigation Satellite Systems (GNSS) observations during the period 2007-2013. The analysis was performed in 73 GNSS tracking sites (GPS + GLONASS) which have more than 5 years of data. The selected area involves different climate types, from polar to tropical, with different diurnal variations of the integrated total humidity content. There are many processes that could induce diurnal variations in atmospheric water vapor (Dai et al, 1999 a,b), the most relevant causes are: surface evapotranspiration, atmospheric large-scale vertical motion, atmospheric low-level moisture convergence and precipitation and vertical mixing (which affects the vertical distribution of water vapor but does not affect the IWV). The numerical tools, Singular Value Decomposition and classical Multidimensional Scaling methods, are used to study these variations, considering the measurements made at each stations, as sample in the analysis. The aim of this investigation is to identify the IWV variability with respect to the local time associated to the different climate regions. In order to improve our analysis, all available weather information, such as radiosondes measurements (which are few), measurements of pressure and temperature and Numerical Weather Models reanalysis data, are used. Reference: Dai, A., K. E. Trenberth, and T. R. Karl, 1999 a: Effects of clouds, soil moisture, precipitation and water vapor on diurnal temperature range. J. Climate, 12, 2451-2473. Dai, A., F. Giorgi, and K. E. Trenberth, 1999 b: Observed and model simulated precipitation diurnal cycle over the contiguous United States.J. Geophys. Res., 104, 6377-6402. KEYWORDS: water vapor, diurnal cycle, GNSS

  9. Proton magnetic relaxation in aromatic polyamides during water vapor sorption

    Science.gov (United States)

    Smotrina, T. V.; Chulkova, Yu. S.; Karasev, D. V.; Lebedeva, N. P.; Perepelkin, K. E.; Grebennikov, S. F.

    2009-07-01

    The state of the components in the aromatic polyamide-water system was studied by NMR and sorption. A comparative analysis of spin-lattice and spin-spin relaxation in aromatic para-polyamide ( para-aramid) technical fibers Rusar, Kevlar, and Technora was performed depending on the sorption value. The NMR results correlated with the supramolecular structure of polymers and quasi-chemical equation parameters for water vapor sorption.

  10. Vaporization of fault water during seismic slip

    NARCIS (Netherlands)

    Chen, Jianye; Niemeijer, André R.; Fokker, Peter A.

    Laboratory and numerical studies, as well as field observations, indicate that phase transitions of pore water might be an important process in large earthquakes. We present a model of the thermo-hydro-chemo-mechanical processes, including a two-phase mixture model to incorporate the phase

  11. Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW) data set measures atmospheric water vapor using ground-based...

  12. Modeling and measurement of boiling point elevation during water vaporization from aqueous urea for SCR applications

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Ho Jin; Lee, Joon Sik [Seoul National University, Seoul (Korea, Republic of)

    2016-03-15

    Understanding of water vaporization is the first step to anticipate the conversion process of urea into ammonia in the exhaust stream. As aqueous urea is a mixture and the urea in the mixture acts as a non-volatile solute, its colligative properties should be considered during water vaporization. The elevation of boiling point for urea water solution is measured with respect to urea mole fraction. With the boiling-point elevation relation, a model for water vaporization is proposed underlining the correction of the heat of vaporization of water in the urea water mixture due to the enthalpy of urea dissolution in water. The model is verified by the experiments of water vaporization as well. Finally, the water vaporization model is applied to the water vaporization of aqueous urea droplets. It is shown that urea decomposition can begin before water evaporation finishes due to the boiling-point elevation.

  13. Advancements in water vapor electrolysis technology. [for Space Station ECLSS

    Science.gov (United States)

    Chullen, Cinda; Heppner, Dennis B.; Sudar, Martin

    1988-01-01

    The paper describes a technology development program whose goal is to develop water vapor electrolysis (WVE) hardware that can be used selectively as localized topping capability in areas of high metabolic activity without oversizing the central air revitalization system on long-duration manned space missions. The WVE will be used primarily to generate O2 for the crew cabin but also to provide partial humidity control by removing water vapor from the cabin atmosphere. The electrochemically based WVE interfaces with cabin air which is controlled in the following ranges: dry bulb temperature of 292 to 300 K; dew point temperature of 278 to 289 K; relative humidity of 25 to 75 percent; and pressure of 101 + or - 1.4 kPa. Design requirements, construction details, and results for both single-cell and multicell module testing are presented, and the preliminary sizing of a multiperson subsystem is discussed.

  14. A new passive sampler for collecting atmospheric tritiated water vapor

    Science.gov (United States)

    Feng, Bin; Chen, Bo; Zhuo, Weihai; Zhang, Weiyuan

    2017-04-01

    A new passive sampler was developed for collecting environmental tritiated water vapor. The construction of the sampler was improved according to computational fluid dynamics (CFD) simulations in which the influence on vapor collection by the turbulence inside the sampler was considered. Through changes in temperature from 5 °C to 35 °C and relative humidity from 45% to 90%, the new sampler revealed stable performance of the sampling rate. Compared with the previous samplers, the new sampler significantly lowered the effect of wind speed. Using the adsorption kinetic curve of the sampler provided in the co-comparison experiments, the quantitative relationship between the mass of adsorbed water and the cumulative absolute humidity exposure was established. Field applications in the vicinity of a nuclear power plant show that the data obtained by the new samplers is consistent with the active measurement. The sampler was preliminarily proven to be reliable and flexible for field investigation of HTO in the atmosphere.

  15. Atmospheric solar heating rate in the water vapor bands

    Science.gov (United States)

    Chou, Ming-Dah

    1986-01-01

    The total absorption of solar radiation by water vapor in clear atmospheres is parameterized as a simple function of the scaled water vapor amount. For applications to cloudy and hazy atmospheres, the flux-weighted k-distribution functions are computed for individual absorption bands and for the total near-infrared region. The parameterization is based upon monochromatic calculations and follows essentially the scaling approximation of Chou and Arking, but the effect of temperature variation with height is taken into account in order to enhance the accuracy. Furthermore, the spectral range is extended to cover the two weak bands centered at 0.72 and 0.82 micron. Comparisons with monochromatic calculations show that the atmospheric heating rate and the surface radiation can be accurately computed from the parameterization. Comparisons are also made with other parameterizations. It is found that the absorption of solar radiation can be computed reasonably well using the Goody band model and the Curtis-Godson approximation.

  16. Water vapor analysis with use of sunphotometry and radiosoundings

    Science.gov (United States)

    Pakszys, Paulina; Zielinski, Tymon; Petelski, Tomek; Makuch, Przemyslaw; Strzalkowska, Agata; Markuszewski, Piotr; Kowalczyk, Jakub

    2014-05-01

    Information about vertically integrated content of water vapor in the atmosphere and type, composition and concentration of aerosols is relevant in many types of atmospheric studies. Such information is required to understand mechanisms of global climate and its further modeling (Smirnov et al., 2000). This work is devoted to the description of a basic technique of analysis and comparing the derivation of Columnar Water Vapor (CWV) from different instruments, such as a radiosonde and a sunphotometer. The measurements were carried out using Microtops II Ozone Monitor & Sunphotometer during the cruises onboard the R/V Oceania (13 cruises) and from one cruise onboard of the SY TASK in the southern Baltic Sea. Measurements were collected for the NASA program Maritime Aerosol Network. Data collected with the DiGICORA III Radiosonde (RS92) come from the webpage of the University of Wyoming, Department of Atmospheric Science. The first instrument, sunphotometer, allows us to collect data on days that are cloud-free. The Microtops II is capable of measuring the total ozone column, total precipitable water vapor and aerosol optical depth at 1020 nm (Morys et al. 2001; Ichoku et al., 2002). Each of these parameters is automatically derived. Data collected by Microtops have been processed with the pre- and post-field calibration and automatic cloud clearing. Precipitable water vapor in the column was derived from the 936nm channel. Detailed data description is available on the AERONET webpage. In radiousoundings the total precipitable water is the water that occurs in a vertical column of a unit cross-sectional area between any two specified levels, commonly expressed as from the earth's surface to the 'top' of the atmosphere. The Integrated Precipitable Water Vapor (IPWV) is the height of liquid water that would result from the condensation of all water vapor in a column. The study of one cruise (29 March - 20 April) shows that 241 Microtops measurements were made, each of

  17. Interpolating atmospheric water vapor delay by incorporating terrain elevation information

    Science.gov (United States)

    Xu, W. B.; Li, Z. W.; Ding, X. L.; Zhu, J. J.

    2011-09-01

    In radio signal-based observing systems, such as Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR), the water vapor in the atmosphere will cause delays during the signal transmission. Such delays vary significantly with terrain elevation. In the case when atmospheric delays are to be eliminated from the measured raw signals, spatial interpolators may be needed. By taking advantage of available terrain elevation information during spatial interpolation process, the accuracy of the atmospheric delay mapping can be considerably improved. This paper first reviews three elevation-dependent water vapor interpolation models, i.e., the Best Linear Unbiased Estimator in combination with the water vapor Height Scaling Model (BLUE + HSM), the Best Linear Unbiased Estimator coupled with the Elevation-dependent Covariance Model (BLUE + ECM), and the Simple Kriging with varying local means based on the Baby semi-empirical model (SKlm + Baby for short). A revision to the SKlm + Baby model is then presented, where the Onn water vapor delay model is adopted to substitute the inaccurate Baby semi-empirical model (SKlm + Onn for short). Experiments with the zenith wet delays obtained through the GPS observations from the Southern California Integrated GPS Network (SCIGN) demonstrate that the SKlm + Onn model outperforms the other three. The RMS of SKlm + Onn is only 0.55 cm, while those of BLUE + HSM, BLUE + ECM and SKlm + Baby amount to 1.11, 1.49 and 0.77 cm, respectively. The proposed SKlm + Onn model therefore represents an improvement of 29-63% over the other known models.

  18. Surface potential of the water liquid-vapor interface

    Science.gov (United States)

    Wilson, Michael A.; Pohorille, Andrew; Pratt, Lawrence R.

    1988-01-01

    An analysis of an extended molecular dynamics calculation of the surface potential (SP) of the water liquid-vapor interface is presented. The SP predicted by the TIP4P model is -(130 + or - 50) mV. This value is of reasonable magnitude but of opposite sign to the expectations based on laboratory experiments. The electrostatic potential shows a nonmonotonic variation with depth into the liquid.

  19. Surface tension of water in the presence of perfluorocarbon vapors.

    Science.gov (United States)

    Chernyshev, Vasiliy S; Skliar, Mikhail

    2014-03-28

    Fluorocarbons are highly hydrophobic, biocompatible compounds with a variety of medical applications. Despite significant interest, the study of interfacial properties of fluorocarbons in aqueous systems has received limited attention. In this study, we investigate the influence of perfluoropentane and perfluorohexane vapors on the surface tension of water at room temperature. The results show a substantial decrease in the surface tension of water in the presence of perfluorocarbon vapors. In the investigated range of partial pressures up to the saturation value, a linear correlation between the surface tension and the partial pressure was found. This suggests that an adsorbed perfluorocarbon layer is formed on the surface of water. For comparison, the effect of the perfluorocarbon vapor on the surface tension of methanol was also investigated and a similar dependence was observed. Our results indicate that the stability and dynamic transitions of fluorocarbon colloids, which may be dispersed under physiological conditions as microdroplets, bubbles, or their combination, are likely affected by the composition of liquid and gas phases.

  20. Adsorption characteristics of water vapor on ferroaluminophosphate for desalination cycle

    KAUST Repository

    Kim, Youngdeuk

    2014-07-01

    The adsorption characteristics of microporous ferroaluminophosphate adsorbent (FAM-Z01, Mitsubishi Plastics) are evaluated for possible application in adsorption desalination and cooling (AD) cycles. A particular interest is its water vapor uptake behavior at assorted adsorption temperatures and pressures whilst comparing them to the commercial silica gels of AD plants. The surface characteristics are first carried out using N2 gas adsorption followed by the water vapor uptake analysis for temperature ranging from 20°C to 80°C. We propose a hybrid isotherm model, composing of the Henry and the Sips isotherms, which can be integrated to satisfactorily fit the experimental data of water adsorption on the FAM-Z01. The hybrid model is selected to fit the unusual isotherm shapes, that is, a low adsorption in the initial section and followed by a rapid vapor uptake leading to a likely micropore volume filling by hydrogen bonding and cooperative interaction in micropores. It is shown that the equilibrium adsorption capacity of FAM-Z01 can be up to 5 folds higher than that of conventional silica gels. Owing to the quantum increase in the adsorbate uptake, the FAM-Z01 has the potential to significantly reduce the footprint of an existing AD plant for the same output capacity. © 2014 Elsevier B.V.

  1. Determination of water vapor and aerosol densities in the tropospheric atmosphere from nitrogen and water vapor raman signals

    CERN Document Server

    Kim, D H; Lee, J M; Yeon, K H; Choi, S C

    1998-01-01

    A Raman lidar system has been developed for the measurement of the water-vapor mixing ratio and the aerosol backscatter and extinction coefficients. To suppress the elastic scattering from the XeCl excimer laser, an acetone edge filter and narrow-band interference filters are used. By using independently calculated backscatter and extinction coefficients, we calculate the lidar ratios (extinction coefficient divided by the backscatter coefficient). The obtained ratios between 30 and 50 sr explain the special characteristics of the aerosol existing in the atmosphere. These ratios are also used as important parameters in the lidar inversion program. We have also obtained the water-vapor mixing ratio and find that big differences exist between the ratios inside the boundary layer and those of other regions.

  2. Water vapor stable isotope observations from tropical Australia

    KAUST Repository

    Parkes, Stephen

    2015-04-01

    The response of the tropical hydrological cycle to anthropogenically induced changes in radiative forcing is one of the largest discrepancies between climate models. Paleoclimate archives of the stable isotopic composition of precipitation in the tropics indicate a relationship with precipitation amount that could be exploited to study past hydroclimate and improve our knowledge of how this region responds to changes in climate forcing. Recently modelling studies of convective parameterizations fitted with water isotopes and remote sensing of water vapor isotopes in the tropics have illustrated uncertainty in the assumed relationship with rainfall amount. Therefore there is a need to collect water isotope data in the tropics that can be used to evaluate these models and help identify the relationships between the isotopic composition of meteoric waters and rainfall intensity. However, data in this region is almost non-existent. Here we present in-situ water vapor isotopic measurements and the HDO retrievals from the co-located Total Column Carbon Observing Network (TCCON) site at Darwin in Tropical Australia. The Darwin site is interestingly placed within the tropical western pacific region and is impacted upon by a clear monsoonal climate, and key climate cycles including ENSO and Madden Julian Oscillations. The analysis of the data illustrated relationships between water vapor isotopes and humidity which demonstrated the role of precipitation processes in the wet season and air mass mixing during the dry season. Further the wet season observations show complex relationships between humidity and isotopes. A simple Rayleigh distillation model was not obeyed, instead the importance of rainfall re-evaporation in generating the highly depleted signatures was demonstrated. These data potentially provide a useful tool for evaluating model parameterizations in monsoonal regions as they demonstrate relationships with precipitation processes that cannot be observed with

  3. Assessment of water vapor content from MIVIS TIR data

    Directory of Open Access Journals (Sweden)

    V. Tramutoli

    2006-06-01

    Full Text Available The main objective of land remotely sensed images is to derive biological, chemical and physical parameters by inverting sample sets of spectral data. For the above aim hyperspectral scanners on airborne platform are a powerful remote sensing instrument for both research and environmental applications because of their spectral resolution and the high operability of the platform. Fine spectral information by MIVIS (airborne hyperspectral scanner operating in 102 channels ranging from VIS to TIR allows researchers to characterize atmospheric parameters and their effects on measured data which produce undesirable features on surface spectral signatures. These effects can be estimated (and remotely sensed radiances corrected if atmospheric spectral transmittance is known at each image pixel. Usually ground-based punctual observations (atmospheric sounding balloons, sun photometers, etc. are used to estimate the main physical parameters (like water vapor and temperature profiles which permit us to estimate atmospheric spectral transmittance by using suitable radiative transfer model and a specific (often too strong assumption which enable atmospheric properties measured only in very few points to be extended to the whole image. Several atmospheric gases produce observable absorption features, but only water vapor strongly varies in time and space. In this work the authors customize a self-sufficient «split-window technique» to derive (at each image pixel atmospheric total columnar water vapor content (TWVC using only MIVIS data collected by the fourth MIVIS spectrometer (Thermal Infrared band. MIVIS radiances have been simulated by means of MODTRAN4 radiative transfer code and the coefficients of linear regression to estimate TWVC from «split-windows» MIVIS radiances, based on 450 atmospheric water vapor profiles obtained by radiosonde data provided by NOAANESDIS. The method has been applied to produce maps describing the spatial variability of

  4. Estimation water vapor content using the mixing ratio method and validated with the ANFIS PWV model

    Science.gov (United States)

    Suparta, W.; Alhasa, K. M.; Singh, M. S. J.

    2017-05-01

    This study reported the comparison between water vapor content, the surface meteorological data (pressure, temperature, and relative humidity), and precipitable water vapor (PWV) produced by PWV from adaptive neuro fuzzy inference system (ANFIS) for areas in the Universiti Kebangsaan Malaysia Bangi (UKMB) station. The water vapor content value was estimated with mixing ratio method and the surface meteorological data as the parameter inputs. The accuracy of water vapor content was validated with PWV from ANFIS PWV model for the period of 20-23 December 2016. The result showed that the water vapor content has a similar trend with the PWV which produced by ANFIS PWV model (r = 0.975 at the 99% confidence level). This indicates that the water vapor content that obtained with mixing ratio agreed very well with the ANFIS PWV model. In addition, this study also found, the pattern of water vapor content and PWV have more influenced by the relative humidity.

  5. Stable isotopic composition of water vapor in the tropics

    Science.gov (United States)

    Lawrence, James Robert; Gedzelman, Stanley David; Dexheimer, Darielle; Cho, Hye-Khung; Carrie, Gordon D.; Gasparini, Robert; Anderson, Casey R.; Bowman, Kenneth P.; Biggerstaff, Mike I.

    2004-03-01

    Water vapor samples collected during tropical field experiments at Puerto Escondido, Mexico, near Kwajalein (KWAJEX), and near Key West, Florida (CAMEX 4), were analyzed for their stable isotope contents, 1H218O:1H216O and 2H1H16O:1H216O. Highest δ18O values approached isotopic equilibrium with seawater during quiescent weather or in regions of isolated or disorganized convection. Lowest δ18O values occurred in or downwind from regions of organized mesoscale weather disturbances and ranged as low as 15‰ below isotopic equilibrium with seawater. The mean δ18O value of vapor over the sea surface therefore decreases as storm activity and organization increases.

  6. Water vapor sorption properties of cellulose nanocrystals and nanofibers using dynamic vapor sorption apparatus.

    Science.gov (United States)

    Guo, Xin; Wu, Yiqiang; Xie, Xinfeng

    2017-10-27

    Hygroscopic behavior is an inherent characteristic of nanocellulose which strongly affects its applications. In this study, the water vapor sorption behavior of four nanocellulose samples, such as cellulose nanocrystals and nanofibers with cellulose I and II structures (cellulose nanocrystals (CNC) I, CNC II, cellulose nanofibers (CNF) I, and CNF II) were studied by dynamic vapor sorption. The highly reproducible data including the running time, real-time sample mass, target relative humidity (RH), actual RH, and isotherm temperature were recorded during the sorption process. In analyzing these data, significant differences in the total running time, equilibrium moisture content, sorption hysteresis and sorption kinetics between these four nanocellulose samples were confirmed. It was important to note that CNC I, CNC II, CNF I, and CNF II had equilibrium moisture contents of 21.4, 28.6, 33.2, and 38.9%, respectively, at a RH of 95%. Then, the sorption kinetics behavior was accurately described by using the parallel exponential kinetics (PEK) model. Furthermore, the Kelvin-Voigt model was introduced to interpret the PEK behavior and calculate the modulus of these four nanocellulose samples.

  7. An optical water vapor sensor for unmanned aerial vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Timothy A. Berkoff; Paul L. Kebabian; Robert A. McClatchy; Charles E. Kolb; Andrew Freedman

    1998-12-01

    The water vapor sensor developed by Aerodyne Research, based on the optical absorption of light at {approximately}935 nm, has been successfully demonstrated on board the Pacific Northwest National Laboratory's Gulfstream-1 research aircraft during the Department of Energy's ARM Intensive Operations Period in August 1998. Data taken during this field campaign show excellent agreement with a chilled mirror and Lyman-alpha hygrometers and measurements confirm the ability to measure rapid, absolute water vapor fluctuations with a high degree of instrument stability and accuracy, with a noise level as low 10 ppmv (1 Hz measurement bandwidth). The construction of this small, lightweight sensor contains several unique elements which result in several significant advantages when compared to other techniques. First, the low power consumption Argon discharge lamp provides an optical beam at a fixed wavelength without a need for temperature or precision current control. The multi-pass absorption cell developed for this instrument provides a compact, low cost method that can survive deployment in the field. Fiber-optic cables, which are used to convey to light between the absorption cell, light source, and detection modules enable remote placement of the absorption cell from the opto-electronics module. Finally, the sensor does not use any moving parts which removes a significant source of potential malfunction. The result is an instrument which maintained its calibration throughout the field measurement campaign, and was not affected by high vibration and large uncontrolled temperature excursions. We believe that the development of an accurate, fast response water vapor monitor described in this report will open up new avenues of aerial-vehicle-based atmospheric research which have been relatively unexplored due to the lack of suitable low-cost, light-weight instrumentation.

  8. Nd:Glass-Raman laser for water vapor dial

    Science.gov (United States)

    Kagann, R. H.; Petheram, J. C.; Rosenberg, A.

    1986-01-01

    A tunable solid-state Raman shifted laser which was used in a water vapor Differential Absorption Lidar (DIAL) system at 9400 A is described. The DIAL transmitter is based on a tunable glass laser operating at 1.06 microns, a hydrogen Raman cell to shift the radiation to 1.88 microns, and a frequency doubling crystal. The results of measurements which characterize the output of the laser with respect to optimization of optical configuration and of Raman parameters were reported. The DIAL system was also described and preliminary atmospheric returns shown.

  9. Water vapor measurement system in global atmospheric sampling program, appendix

    Science.gov (United States)

    Englund, D. R.; Dudzinski, T. J.

    1982-01-01

    The water vapor measurement system used in the NASA Global Atmospheric Sampling Program (GASP) is described. The system used a modified version of a commercially available dew/frostpoint hygrometer with a thermoelectrically cooled mirror sensor. The modifications extended the range of the hygrometer to enable air sample measurements with frostpoint temperatures down to -80 C at altitudes of 6 to 13 km. Other modifications were made to permit automatic, unattended operation in an aircraft environment. This report described the hygrometer, its integration with the GASP system, its calibration, and operational aspects including measurement errors. The estimated uncertainty of the dew/frostpoint measurements was + or - 1.7 Celsius.

  10. Water vapor toward starless cores: The Herschel view

    Science.gov (United States)

    Caselli, P.; Keto, E.; Pagani, L.; Aikawa, Y.; Yıldız, U. A.; van der Tak, F. F. S.; Tafalla, M.; Bergin, E. A.; Nisini, B.; Codella, C.; van Dishoeck, E. F.; Bachiller, R.; Baudry, A.; Benedettini, M.; Benz, A. O.; Bjerkeli, P.; Blake, G. A.; Bontemps, S.; Braine, J.; Bruderer, S.; Cernicharo, J.; Daniel, F.; di Giorgio, A. M.; Dominik, C.; Doty, S. D.; Encrenaz, P.; Fich, M.; Fuente, A.; Gaier, T.; Giannini, T.; Goicoechea, J. R.; de Graauw, Th.; Helmich, F.; Herczeg, G. J.; Herpin, F.; Hogerheijde, M. R.; Jackson, B.; Jacq, T.; Javadi, H.; Johnstone, D.; Jørgensen, J. K.; Kester, D.; Kristensen, L. E.; Laauwen, W.; Larsson, B.; Lis, D.; Liseau, R.; Luinge, W.; Marseille, M.; McCoey, C.; Megej, A.; Melnick, G.; Neufeld, D.; Olberg, M.; Parise, B.; Pearson, J. C.; Plume, R.; Risacher, C.; Santiago-García, J.; Saraceno, P.; Shipman, R.; Siegel, P.; van Kempen, T. A.; Visser, R.; Wampfler, S. F.; Wyrowski, F.

    2010-10-01

    Aims: Previous studies by the satellites SWAS and Odin provided stringent upper limits on the gas phase water abundance of dark clouds (x(H2O) 7000 AU and ≃2 × 10-10 toward the center. The radiative transfer analysis shows that this is consistent with a x(o-H2O) profile peaking at ≃10-8, 0.1 pc away from the core center, where both freeze-out and photodissociation are negligible. Conclusions: Herschel has provided the first measurement of water vapor in dark regions. Column densities of o-H2O are low, but prestellar cores such as L1544 (with their high central densities, strong continuum, and large envelopes) appear to be very promising tools to finally shed light on the solid/vapor balance of water in molecular clouds and oxygen chemistry in the earliest stages of star formation. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  11. Remote sensing evidence for regolith water vapor sources on Mars

    Science.gov (United States)

    Huguenin, R. L.; Clifford, S. M.

    1982-01-01

    McCord et al. (1977) have presented earth-based photometric imaging data of an event associated with the 1973 dust storm on Mars. The initial dust cloud in Solis Lacus and two regions to the north and south appeared anomalously bright at blue wavelengths. Water frosts, hazes, and/or clouds were identified, and it was suggested that the water responsible for these findings may have originated from Solis Lacus. More recently, a more intensive review of the observational record of Mars was undertaken. Earth-based telescope observations and data from the Mariner and Viking missions have revealed that Solis Lacus has been a center of repeated activity. Persistent activity in the vicinity of Noachis-Hellespontus and in the border regions of Syrtis Major was also discovered. A review of the observations is provided and possible interpretations are discussed. The obtained results appear to support the original proposal that Solis Lacus may be a source of water vapor. Noachis-Hellespontus seems to be a similar vapor source

  12. Ricor's Nanostar water vapor compact cryopump: applications and model overview

    Science.gov (United States)

    Harris, Rodney S.; Nachman, Ilan; Tauber, Tomer; Kootzenko, Michael; Barak, Boris; Aminov, Eli; Gover, Dan

    2017-05-01

    Ricor Systems has developed a compact, single stage cryopump that fills the gap where GM and other type cryopumps can't fit in. Stirling cycle technology is highly efficient and is the primary cryogenic technology for use in IR, SWIR, HOT FPA, and other IR detector technology in military, security, and aerospace applications. Current GM based dual stage cryopumps have been the legacy type water vapor pumping system for more than 50 years. However, the typically large cryopanel head, compressor footprint, and power requirements make them not cost and use effective for small, tabletop evaporation / sputtering systems, portable analysis systems, and other systems requiring small volume vacuum creation from medium, high, and UHV levels. This single stage cryopump works well in-line with diffusion and molecular turbopumps. Studies have shown effective cooperation with non-evaporable getter technology as well for UHV levels. Further testing in this area are ongoing. Temperatures created by Stirling cycle cryogenic coolers develop a useful temperature range of 40 to 150K. Temperatures of approximately 100 K are sufficient to condense water and all hydrocarbons oil vapors.

  13. Raman lidar water vapor profiling over Warsaw, Poland

    Science.gov (United States)

    Stachlewska, Iwona S.; Costa-Surós, Montserrat; Althausen, Dietrich

    2017-09-01

    Water vapor mixing ratio and relative humidity profiles were derived from the multi-wavelength Raman PollyXT lidar at the EARLINET site in Warsaw, using the Rayleigh molecular extinction calculation based on atmospheric temperature and pressure from three different sources: i) the standard atmosphere US 62, ii) the Global Data Assimilation System (GDAS) model output, and iii) the WMO 12374 radiosoundings launched at Legionowo. With each method, 136 midnight relative humidity profiles were obtained for lidar observations from July 2013 to August 2015. Comparisons of these profiles showed in favor of the latter method (iii), but it also indicated that the other two data sources could replace it, if necessary. Such use was demonstrated for an automated retrieval of water vapor mixing ratio from dusk until dawn on 19/20 March 2015; a case study related to an advection of biomass burning aerosol from forest fires over Ukraine. Additionally, an algorithm that applies thresholds to the radiosounding relative humidity profiles to estimate macro-physical cloud vertical structure was used for the first time on the Raman lidar relative humidity profiles. The results, based on a subset of 66 profiles, indicate that below 6 km cloud bases/tops can be successfully obtained in 53% and 76% cases from lidar and radiosounding profiles, respectively. Finally, a contribution of the lidar derived mean relative humidity to cloudy conditions within the range of 0.8 to 6.2 km, in comparison to clear-sky conditions, was estimated.

  14. Characterization of Upper Troposphere Water Vapor Measurements during AFWEX using LASE

    Science.gov (United States)

    Ferrare, R. A.; Browell, E. V.; Ismail, S.; Kooi, S.; Brasseur, L. H.; Brackett, V. G.; Clayton, M.; Barrick, J.; Linne, H.; Lammert, A.

    2002-01-01

    Water vapor profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the ARM/FIRE Water Vapor Experiment (AFWEX) are used to characterize upper troposphere water vapor (UTWV) measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors. Initial comparisons showed the average Vaisala radiosonde measurements to be 5-15% drier than the average LASE, Raman lidar, and DC-8 in situ diode laser hygrometer measurements. We show that corrections to the Raman lidar and Vaisala measurements significantly reduce these differences. Precipitable water vapor (PWV) derived from the LASE water vapor profiles agrees within 3% on average with PWV derived from the ARM ground-based microwave radiometer (MWR). The agreement among the LASE, Raman lidar, and MWR measurements demonstrates how the LASE measurements can be used to characterize both profile and column water vapor measurements and that ARM Raman lidar, when calibrated using the MWR PWV, can provide accurate UTWV measurements.

  15. Modeling and Prediction of Soil Water Vapor Sorption Isotherms

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

    2015-01-01

    Soil water vapor sorption isotherms describe the relationship between water activity (aw) and moisture content along adsorption and desorption paths. The isotherms are important for modeling numerous soil processes and are also used to estimate several soil (specific surface area, clay content......, cation exchange capacity) and engineering properties (e.g., swelling potential). Our objectives for this work were to: (i) evaluate the potential of several theoretical and empirical isotherm models to accurately describe measured moisture adsorption/desorption isotherms (aw range of 0.03 to 0.......93) for a wide range of soils; and (ii) develop and test regression models for estimating the isotherms from clay content. Preliminary results show reasonable fits of the majority of the investigated empirical and theoretical models to the measured data although some models were not capable to fit both sorption...

  16. Feasibility of tropospheric water vapor profiling using infrared heterodyne differential absorption lidar

    Energy Technology Data Exchange (ETDEWEB)

    Grund, C.J.; Hardesty, R.M. [National Oceanic and Atmospheric Administration Environmental Technology Laboratoy, Boulder, CO (United States); Rye, B.J. [Univ. of Colorado, Boulder, CO (United States)

    1996-04-01

    The development and verification of realistic climate model parameterizations for clouds and net radiation balance and the correction of other site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. In this study, we develop system performance models and examine the potential of infrared differential absoroption lidar (DIAL) to determine the concentration of water vapor.

  17. Six-channel multi-wavelength polarization Raman lidar for aerosol and water vapor profiling.

    Science.gov (United States)

    Wang, Zhaofei; Mao, Jiandong; Li, Juan; Zhao, Hu; Zhou, Chunyan; Sheng, Hongjiang

    2017-07-10

    Aerosols and water vapor are important atmospheric components, and have significant effects on both atmospheric energy conversion and climate formation. They play the important roles in balancing the radiation budget between the atmosphere and Earth, while water vapor also directly affects rainfall and other weather processes. To further research atmospheric aerosol optical properties and water vapor content, an all-time six-channel multi-wavelength polarization Raman lidar has been developed at Beifang University of Nationalities. In addition to 1064, 532, and 355 nm Mie scattering channels, the lidar has a polarization channel for 532 nm return signals, a 660 nm water vapor channel, and a 607 nm nitrogen detection channel. Experiments verified the lidar's feasibility and return signals from six channels were detected. Using inversion algorithms, extinction coefficient profiles at 1064, 532 and 355 nm, Ångström exponent profiles, depolarization ratio profiles, and water vapor mixing ratio profiles were all obtained. The polarization characteristics and water vapor content of cirrus clouds, the polarization characteristics of dusty weather, and the water vapor profiles over different days were also analyzed. Results show that the lidar has the full-time detection capability for atmospheric aerosol optical properties and water vapor profiles, and real-time measurements of aerosols and water vapor over the Yinchuan area were realized, providing important information for studying the environmental quality and climate change in this area.

  18. Cold Water Vapor in the Barnard 5 Molecular Cloud

    Science.gov (United States)

    Wirstrom, E. S.; Charnley, S. B.; Persson, C. M.; Buckle, J. V.; Cordiner, M. A.; Takakuwa, S.

    2014-01-01

    After more than 30 yr of investigations, the nature of gas-grain interactions at low temperatures remains an unresolved issue in astrochemistry. Water ice is the dominant ice found in cold molecular clouds; however, there is only one region where cold ((is) approximately 10 K) water vapor has been detected-L1544. This study aims to shed light on ice desorption mechanisms under cold cloud conditions by expanding the sample. The clumpy distribution of methanol in dark clouds testifies to transient desorption processes at work-likely to also disrupt water ice mantles. Therefore, the Herschel HIFI instrument was used to search for cold water in a small sample of prominent methanol emission peaks. We report detections of the ground-state transition of o-H2O (J = 110-101) at 556.9360 GHz toward two positions in the cold molecular cloud, Barnard 5. The relative abundances of methanol and water gas support a desorption mechanism which disrupts the outer ice mantle layers, rather than causing complete mantle removal.

  19. Compact Water Vapor Exchanger for Regenerative Life Support Systems

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Anderson, Molly; Hodgson, Edward

    2012-01-01

    Thermal and environmental control systems for future exploration spacecraft must meet challenging requirements for efficient operation and conservation of resources. Regenerative CO2 removal systems are attractive for these missions because they do not use consumable CO2 absorbers. However, these systems also absorb and vent water to space along with carbon dioxide. This paper describes an innovative device designed to minimize water lost from regenerative CO2 control systems. Design studies and proof-of-concept testing have shown the feasibility of a compact, efficient membrane water vapor exchanger (WVX) that will conserve water while meeting challenging requirements for operation on future spacecraft. Compared to conventional WVX designs, the innovative membrane WVX described here has the potential for high water recovery efficiency, compact size, and very low pressure losses. The key innovation is a method for maintaining highly uniform flow channels in a WVX core built from water-permeable membranes. The proof-of-concept WVX incorporates all the key design features of a prototypical unit, except that it is relatively small scale (1/23 relative to a unit sized for a crew of six) and some components were fabricated using non-prototypical methods. The proof-of-concept WVX achieved over 90% water recovery efficiency in a compact core in good agreement with analysis models. Furthermore the overall pressure drop is very small (less than 0.5 in. H2O, total for both flow streams) and meets requirements for service in environmental control and life support systems on future spacecraft. These results show that the WVX provides very uniform flow through flow channels for both the humid and dry streams. Measurements also show that CO2 diffusion through the water-permeable membranes will have negligible effect on the CO2 partial pressure in the spacecraft atmosphere.

  20. DMSP SSM/T-2 microwave water vapor profiler

    Science.gov (United States)

    Galin, Israel; Brest, Dennis H.; Martner, Glen R.

    1993-08-01

    The Special Sensor Microwave water vapor profiler (SSM/T-2) is a five channel passive microwave sensor that operates in the 90 - 190 GHz frequency band. The instrument was developed by Aerojet Electronic Systems Division (AESD) of GenCorp Aerojet under a contract to the Defense Meteorological Satellite Program (DMSP). The first in a series of these instruments was successfully orbited in November 1991. This paper addresses details of the instrument configuration, as well as relevant information on the status of the project. A block diagram of the instrument is described in relation to its electrical, environmental and reliability requirements. Performance data measured in laboratory conditions is presented along with data from the operating unit in orbit.

  1. Development of an OF-CEAS laser spectrometer for water vapor isotope measurements at low water concentrations

    NARCIS (Netherlands)

    Landsberg, Janek

    2014-01-01

    The determination of the isotopic composition of water vapor is an important tool in atmospheric research. The isotopic composition of water in Antarctic or Arctic glacial ice can be used as a paleo-thermometer in the reconstruction of climate changes in the past. The isotope ratios of water vapor

  2. Fossil Fuel Combustion Fingerprint in High-Resolution Urban Water Vapor Isotope Measurements

    Science.gov (United States)

    Gorski, G.; Good, S. P.; Bowen, G. J.

    2014-12-01

    Increasing energy consumption and rapid urbanization have many important and poorly understood consequences for the hydrologic cycle in urban and suburban areas. Wide use of fossil fuels for transportation and heating releases isotopically distinctive water vapor that contributes to the overall water vapor budget in varying, usually unknown, concentrations. The use of long term, high resolution isotopic measurements can help determine different sources and proportions of water vapor at various time scales. We present two months of high-resolution water vapor isotope measurements coupled with CO2 concentrations and co-located meteorological observations from December 2013 - January 2014 in Salt Lake City, UT. Periods of atmospheric stagnation (cold-air inversions) show a buildup of CO2 from baseline values of 420 ppm to as high as 600 ppm and an associated decrease in water vapor deuterium-excess values from a baseline of approx. 10‰ to values as low as -10‰ (where d = δ2H - 8*δ18O, in per mil units). We suggest that the strong relationship between CO2and d during inversion periods is driven by the build-up of fossil fuel combustion-derived water vapor with very low d values (≤ -150‰). Based on our measurements of its isotopic composition, combustion-derived water vapor could contribute as much as 15% to the total water vapor budget during inversion periods. We present evidence of this effect at both the multi-day scale and the diurnal scale, where periods of increased automobile use and home heating can be identified. This study provides the first isotopic evidence that accumulation of water of combustion can be identified in boundary layer water vapor, suggests that an appreciable fraction of boundary layer vapor can be derived from combustion under certain atmospheric conditions, and indicates that the distinctive d values of combustion-derived vapor may be a useful tracer for this component of the atmospheric water budget in other urban regions.

  3. Development and Validation of Water Vapor Tracers as Diagnostics for the Atmospheric Hydrologic Cycle

    Science.gov (United States)

    Bosilovich, Michael G.; Schubert, Siegfried D.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Understanding of the local and remote sources of water vapor can be a valuable diagnostic in understanding the regional atmospheric hydrologic cycle. In the present study, we have implemented passive tracers as prognostic variables to follow water vapor evaporated in predetermined regions until the water tracer precipitates. The formulation of the sources and sinks of tracer water is generally proportional to the prognostic water vapor variable. Because all water has been accounted for in tracers, the water vapor variable provides the validation of the tracer water and the formulation of the sources and sinks. The tracers have been implemented in a GEOS General Circulation Model (GCM) simulation consisting of several summer periods to determine the source regions of precipitation for the United States and India. The recycling of water and interannual variability of the sources of water will be examined. Potential uses in GCM sensitivity studies, predictability studies and data assimilation will be discussed.

  4. Formation and survival of water vapor in the terrestrial planet-forming region.

    Science.gov (United States)

    Bethell, Thomas; Bergin, Edwin

    2009-12-18

    Recent astronomical observations have revealed what may prove to be the ubiquity of water vapor during the early stages of planet formation. We present here a simple mechanism showing how water vapor forms in situ and is capable of shielding itself from molecule-destroying stellar radiation. The absorption of this radiation by water can control the thermodynamics of the terrestrial planet-forming zone. Similar to Earth's ozone layer, which shelters the chemistry of life, the water layer protects other water molecules and allows for a rich organic chemistry. The total abundance of water vapor in the natal habitable zone is equal to that of several thousand oceans.

  5. Enhanced Positive Water Vapor Feedback Associated with Tropical Deep Convection: New Evidence from Aura MLS

    Science.gov (United States)

    Su, Hui; Read, William G.; Jiang, Jonathan H.; Waters, Joe W.; Wu, Dong L.; Fetzer, Eric J.

    2006-01-01

    Recent simultaneous observations of upper tropospheric (UT) water vapor and cloud ice from the Microwave Limb Sounder (MLS) on the Aura satellite provide new evidence for tropical convective influence on UT water vapor and its associated greenhouse effect. The observations show that UT water vapor increases as cloud ice water content increases. They also show that, when sea surface temperature (SST) exceeds approx.300 K, UT cloud ice associated with tropical deep convection increases sharply with increasing SST. The moistening of the upper troposphere by deep convection leads to an enhanced positive water vapor feedback, about 3 times that implied solely by thermodynamics. Over tropical oceans when SST greater than approx.300 K, the 'convective UT water vapor feedback' inferred from the MLS observations contributes approximately 65% of the sensitivity of the clear-sky greenhouse parameter to SST.

  6. Water and water vapor sorption studies in polypropylene-zeolite composites

    OpenAIRE

    Pehlivan, H.; Özmıhçı, Filiz; Tıhmınlıoğlu, Funda; Balköse, Devrim; Ülkü, Semra

    2003-01-01

    Water and water vapor sorption to porous polypropylene-zeolite composites prepared by hot pressing have been studied as a function of zeolite loading. This work presents the first report on the effect of the zeolite as a filler on the water-sorption properties of PP composites. Water swelling experiments were conducted at 25°C using pure PP and PP-zeolite films samples having different zeolite loadings (6-40 wt %). Because PP is a hydrophobic polymer, it does not sorp any water, but the compo...

  7. A steady-state analysis of the temperature responses of water vapor and aerosol lifetimes

    NARCIS (Netherlands)

    Roelofs, G.J.H.|info:eu-repo/dai/nl/100925375

    2013-01-01

    The dominant removal mechanism of soluble aerosol is wet deposition. The atmospheric lifetime of aerosol, relevant for aerosol radiative forcing, is therefore coupled to the atmospheric cycling time of water vapor. This study investigates the coupling between water vapor and aerosol lifetimes in a

  8. Stable isotopes in atmospheric water vapor and applications to the hydrologic cycle

    Science.gov (United States)

    Galewsky, Joseph; Steen-Larsen, Hans Christian; Field, Robert D.; Worden, John; Risi, Camille; Schneider, Matthias

    2016-12-01

    The measurement and simulation of water vapor isotopic composition has matured rapidly over the last decade, with long-term data sets and comprehensive modeling capabilities now available. Theories for water vapor isotopic composition have been developed by extending the theories that have been used for the isotopic composition of precipitation to include a more nuanced understanding of evaporation, large-scale mixing, deep convection, and kinetic fractionation. The technologies for in situ and remote sensing measurements of water vapor isotopic composition have developed especially rapidly over the last decade, with discrete water vapor sampling methods, based on mass spectroscopy, giving way to laser spectroscopic methods and satellite- and ground-based infrared absorption techniques. The simulation of water vapor isotopic composition has evolved from General Circulation Model (GCM) methods for simulating precipitation isotopic composition to sophisticated isotope-enabled microphysics schemes using higher-order moments for water and ice size distributions. The incorporation of isotopes into GCMs has enabled more detailed diagnostics of the water cycle and has led to improvements in its simulation. The combination of improved measurement and modeling of water vapor isotopic composition opens the door to new advances in our understanding of the atmospheric water cycle, in processes ranging from the marine boundary layer, through deep convection and tropospheric mixing, and into the water cycle of the stratosphere. Finally, studies of the processes governing modern water vapor isotopic composition provide an improved framework for the interpretation of paleoclimate proxy records of the hydrological cycle.

  9. An interim reference model for the variability of the middle atmosphere water vapor distribution

    Science.gov (United States)

    Remsberg, E. E.; Russell, J. M., III; Wu, C.-Y.

    1990-01-01

    A reference model for the middle atmosphere water vapor distribution for some latitudes and seasons was developed using two data sets. One is the seven months of Nimbus LIMS data obtained during November 1978 to May 1979 over the range 64 deg S - 84 deg N latitude and from about 100-mb to 1-mb altitude, and the other is represented by water vapor profiles from 0.2 mb to 0.01 mb in the mid-mesosphere, measured on ground at several fixed mid-latitude sites in the Northern Hemisphere, using microwave-emission techniques. This model provides an interim water vapor profile for the entire vertical range of the middle atmosphere, with accuracies of better than 25 percent. The daily variability of stratospheric water vapor profiles about the monthly mean is demonstrated, and information is provided on the longitudinal variability of LIMS water vapor profiles about the daily, weekly, and monthly zonal means.

  10. MODIS/Aqua Granule Level 2 Water Vapor Near Infrared Jpeg image

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a Jpeg image product generated from MODIS Level 2 Precipitable Water product (MYD05_L2) using WATER_VAPOR_NEAR_INFRARED parameter. For more information about...

  11. MODIS/Terra Granule Level 2 Water Vapor Near Infrared Jpeg image

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a Jpeg image product generated from MODIS Level 2 Precipitable Water product (MOD05_L2) using WATER_VAPOR_NEAR_INFRARED parameter. For more information about...

  12. SAFARI 2000 MODIS MOD05_L2 Water Vapor Data, Binary Format, for Southern Africa

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODIS precipitable water product consists of vertical column water-vapor amounts in centimeters (cm) at 1 km spatial resolution. The SAFARI 2000 product,...

  13. Isobaric vapor-liquid equilibria for methanol + ethanol + water and the three constituent binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Kurihara, Kiyofumi; Nakamichi, Mikiyoshi; Kojima, Kazuo (Nihon Univ., Tokyo (Japan). Dept. of Industrial Chemistry)

    1993-07-01

    Vapor-liquid equilibrium data for methanol + ethanol + water and its three constituent binary systems methanol + ethanol, ethanol + water, and methanol + water were measured at 101.3 kPa using a liquid-vapor ebullition-type equilibrium still. The experimental binary data were correlated by the NRTL equation. The ternary system methanol + ethanol + water was predicted by means of the binary NRTL parameters with good accuracy.

  14. Polybenzimidazole-based mixed membranes with exceptional high water vapor permeability and selectivity

    KAUST Repository

    Akhtar, Faheem Hassan

    2017-09-13

    Polybenzimidazole (PBI), a thermal and chemically stable polymer, is commonly used to fabricate membranes for applications like hydrogen recovery at temperatures of more than 300 °C, fuel cells working in a highly acidic environment, and nanofiltration in aggressive solvents. This report shows for the first time use of PBI dense membranes for water vapor/gas separation applications. They showed an excellent selectivity and high water vapor permeability. Incorporation of inorganic hydrophilic titanium-based nano-fillers into the PBI matrix further increased the water vapor permeability and water vapor/N2 selectivity. The most selective mixed matrix membrane with 0.5 wt% loading of TiO2 nanotubes yielded a water vapor permeability of 6.8×104 Barrer and a H2O/N2 selectivity of 3.9×106. The most permeable membrane with 1 wt% loading of carboxylated TiO2 nanoparticles had a 7.1×104 Barrer water vapor permeability and a H2O/N2 selectivity of 3.1×106. The performance of these membranes in terms of water vapor transport and selectivity is among the highest reported ones. The remarkable ability of PBI to efficiently permeate water versus other gases opens the possibility to fabricate membranes for dehumidification of streams in harsh environments. This includes the removal of water from high temperature reaction mixtures to shift the equilibrium towards products.

  15. The Annual Cycle of Water Vapor on Mars as Observed by the Thermal Emission Spectrometer

    Science.gov (United States)

    Smith, Michael D.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water vapor for over one full Martian year (March 1999-March 2001). A maximum in water vapor abundance is observed at high latitudes during mid-summer in both hemispheres, reaching a maximum value of approximately 100 pr-micrometer in the north and approximately 50 pr-micrometer in the south. Low water vapor abundance (water vapor. The latitudinal and seasonal dependence of the decay of the northern summer water vapor maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually-averaged water vapor (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface pressure. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments shows some similar features, but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD and the large latitudinal gradient in annually-averaged water vapor observed by MAWD does not appear in the TES results.

  16. Evaluating the Impact of Ambient Benzene Vapor Concentrations on Product Water of Condensation Water from Air Technology

    Science.gov (United States)

    2016-03-07

    benzene vapor concentrations representing average outdoor polluted (50 µg/m3) and indoor industrial (640 µg/m3) settings as well as two temperatures...Henry Law calculations estimate. Benzene vapor concentrations representing a polluted outdoor environment resulted in benzene product water...Agency for Toxic Substances and Diseases Registry ATM Atmosphere C Celsius CWFA Condensation Water From Air ECBC Edgewood Chemical

  17. Millimeter-wave Radiometer for High Sensitivity Water Vapor Profiling in Arid Regions

    Energy Technology Data Exchange (ETDEWEB)

    Pazmany, Andrew

    2006-11-09

    Abstract - ProSensing Inc. has developed a G-band (183 GHz) water Vapor Radiometer (GVR) for long-term, unattended measurements of low concentrations of atmospheric water vapor and liquid water. Precipitable water vapor and liquid water path are estimated from zenith brightness temperatures measured from four double-sideband receiver channels, centered at 183.31 1, 3 and 7, and 14 GHz. A prototype ground-based version of the instrument was deployed at the DOE ARM program?s North Slope of Alaska site near Barrow AK in April 2005, where it collected data continuously for one year. A compact, airborne version of this instrument, packaged to operate from a standard 2-D PMS probe canister, has been tested on the ground and is scheduled for test flights in the summer of 2006. This paper presents design details, laboratory test results and examples of retrieved precipitable water vapor and liquid water path from measured brightness temperature data.

  18. Material gap membrane distillation: A new design for water vapor flux enhancement

    KAUST Repository

    Francis, Lijo

    2013-08-19

    A new module design for membrane distillation, namely material gap membrane distillation (MGMD), for seawater desalination has been proposed and successfully tested. It has been observed that employing appropriate materials between the membrane and the condensation plate in an air gap membrane distillation (AGMD) module enhanced the water vapor flux significantly. An increase in the water vapor flux of about 200-800% was observed by filling the gap with sand and DI water at various feed water temperatures. However, insulating materials such as polypropylene and polyurethane have no effect on the water vapor flux. The influence of material thickness and characteristics has also been investigated in this study. An increase in the water gap width from 9. mm to 13. mm increases the water vapor flux. An investigation on an AGMD and MGMD performance comparison, carried out using two different commercial membranes provided by different manufacturers, is also reported in this paper. © 2013 Elsevier B.V.

  19. Catalytic combustion of styrene over copper based catalyst: inhibitory effect of water vapor.

    Science.gov (United States)

    Pan, Hongyan; Xu, Mingyao; Li, Zhong; Huang, Sisi; He, Chun

    2009-07-01

    The effects of water vapor on the activity of the copper based catalysts with different supports such as CuO/gamma-Al2O3, CuO/SiO2 and CuO/TiO2 for styrene combustion were investigated. The catalytic activity of the catalysts was tested in the absence of and presence of water vapor and the catalysts were characterized. Temperature programmed desorption (TPD) experiments and diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) measurements were conducted in order to estimate and explain the water effects. Results showed that the existence of water vapor had a significant negative effect on the catalytic activity of these copper based catalysts due to the competition adsorption of water molecule. DRIFTS studies showed that the catalyst CuO/gamma-Al2O3 had the strongest adsorption of water, while the catalyst CuO/TiO2 had the weakest adsorption of water. H2O-TPD studies also indicated that the order of desorption activation energies of water vapor on the catalysts or the strength of interactions of water molecules with the surfaces of the catalysts was CuO/gamma-Al2O3>CuO/SiO2>CuO/TiO2. As a consequence of that, the CuO/TiO2 exhibited the better durability to water vapor, while CuO/gamma-Al2O3 had the poorest durability to water vapor among these three catalysts.

  20. Water vapor adsorption isotherms of agar-based nanocomposite films.

    Science.gov (United States)

    Rhim, Jong-Whan

    2011-10-01

    Adsorption isotherms of agar and agar/clay nanocomposite films prepared with different types of nanoclays, that is, a natural montmorillonite (Cloisite Na(+) ) and 2 organically modified montmorillonites (Cloisite 30B and Cloisite 20A), were determined at 3 different temperatures (10, 25, and 40 °C). The water vapor adsorption behavior of the nanocomposite films was found to be greatly influenced with the type of clay. The Guggenheim-Anderson-de Boer (GAB) isotherm model parameters were estimated by using both polynomial regression and nonlinear regression methods and it was found that the GAB model fitted adequately for describing experimental adsorption isotherm data for the film samples. The monolayer moisture content (m(o) ) of the film samples was also greatly affected by the type of nanoclay used, that is, m(o) of nanocomposite films was significantly lower than that of the neat agar film. Nanocomposite films prepared with hydrophobic nanoclays (Cloisite 30B and Cloisite 20A) exhibited lower m(o) values than those prepared with hydrophilic nanoclay (Cloisite Na(+) ). © 2011 Institute of Food Technologists®

  1. Atmospheric water vapor retrieval from Landsat 8 thermal infrared images

    Science.gov (United States)

    Ren, Huazhong; Du, Chen; Liu, Rongyuan; Qin, Qiming; Yan, Guangjian; Li, Zhao-Liang; Meng, Jinjie

    2015-03-01

    Atmospheric water vapor (wv) is required for the accurate retrieval of the land surface temperature from remote sensing data and other applications. This work aims to estimate wv from Landsat 8 Thermal InfraRed Sensor (TIRS) images using a new modified split-window covariance-variance ratio (MSWCVR) method on the basis of the brightness temperatures of two thermal infrared bands. Results show that the MSWCVR method can theoretically retrieve wv with an accuracy better than 0.3 g/cm2 for dry atmosphere (wv Robotic Network) ground-measured data and MODIS (Moderate Resolution Imaging Spectroradiometer) products. The results show that the retrieved wv from the TIRS data is highly correlated with the wv of AERONET and MODIS but is generally larger. This difference was probably attributed to the uncertainty of radiometric calibration and stray light coming outside from field of view of TIRS instrument in the current images. Consequently, the data quality and radiometric calibration of the TIRS data should be improved in the future.

  2. In situ separation of root hydraulic redistribution of soil water from liquid and vapor transport

    Science.gov (United States)

    Jeffrey M. Warren; J. Renée Brooks; Maria I. Dragila; Frederick C. Meinzer

    2011-01-01

    Nocturnal increases in water potential and water content in the upper soil profile are often attributed to root water efflux, a process termed hydraulic redistribution (HR). However, unsaturated liquid or vapor flux of water between soil layers independent of roots also contributes to the daily recovery in water content, confounding efforts to determine the actual...

  3. Seasonal Trends in Stratospheric Water Vapor as Derived from SAGE II Data

    Science.gov (United States)

    Roell, Marilee M.; Fu, Rong

    2008-01-01

    Published analysis of HALOE and Boulder balloon measurements of water vapor have shown conflicting trends in stratospheric water vapor for the periods of 1981 through 2005. Analysis of the SAGE II monthly mean water vapor data filtered for large aerosol events for time periods from 1985-1991, 1995-1999, and 2000-2005 have shown a globally decreasing water vapor trend at 17.5km. Seasonal analysis for these three time periods show a decreasing trend in water vapor at 17.5km for the winter and spring seasons. The summer and autumn seasonal analysis show a decreasing trend from 1985-2005, however, there is a increasing trend in water vapor at 17.5km for these seasons during 1995-2005. Latitude vs height seasonal analysis show a decreasing trend in the lower stratosphere between 20S - 20N for the autumn season, while at the latitudes of 30-50S and 30-50N there is an increasing trend in water vapor at heights up to 15km for that season. Comparison with regions of monsoon activity (Asian and North American) show that the Asian monsoon region had some effect on the lower stratospheric moistening in 1995-1999, however, for the time period of 2000-2005, there was no change in the global trend analysis due to either monsoon region. This may be due to the limitations of the SAGE II data from 2000-2005.

  4. Carbon and Water Vapor Fluxes of Different Ecosystems in Oklahoma

    Science.gov (United States)

    Wagle, P.; Gowda, P. H.; Northup, B. K.

    2016-12-01

    Information on exchange of energy, carbon dioxide (CO2), and water vapor (H2O) for major terrestrial ecosystems is vital to quantify carbon and water balances on a large-scale. It is also necessary to develop, test, and improve crop models and satellite-based production efficiency and evapotranspiration (ET) models, and to better understand the potential of terrestrial ecosystems to mitigate rising atmospheric CO2 concentration and climate change. A network (GRL-FLUXNET) of nine eddy flux towers has been established over a diverse range of terrestrial ecosystems, including native and improved perennial grasslands [unburned and grazed tallgrass prairie, burned and grazed tallgrass prairie, and burned Bermuda grass (Cynodon dactylon L.)], grazed and non-grazed winter wheat (Triticum aestivum L.), till and no-till winter wheat and canola (Brassica napus L.), alfalfa (Medicago sativa L.), and soybean (Glycine max L.), at the USDA-ARS, Grazinglands Research Laboratory, El Reno, OK. In this presentation, we quantify and compare net ecosystem CO2 exchange (NEE) and ET between recently burned and grazed tallgrass prairie and burned and non-grazed Bermuda grass pastures, alfalfa, and soybean. Preliminary results show monthly ensembles average NEE reached seasonal peak values of -29, -35, -25, and -20 µmol m-2 s-1 in burned tallgrass prairie pasture, burned Bermuda grass pasture, alfalfa, and soybean, respectively. Similarly, monthly ensembles average ET reached seasonal peak values of 0.22, 0.27, 0.25, 0.28 mm 30-min-1 in burned tallgrass prairie pasture, burned Bermuda grass pasture, alfalfa, and soybean, respectively. Seasonal patterns and daily magnitudes of NEE and ET and their responses to the similar climatic conditions will be further investigated.

  5. Water vapor mass balance method for determining air infiltration rates in houses

    Science.gov (United States)

    David R. DeWalle; Gordon M. Heisler

    1980-01-01

    A water vapor mass balance technique that includes the use of common humidity-control equipment can be used to determine average air infiltration rates in buildings. Only measurements of the humidity inside and outside the home, the mass of vapor exchanged by a humidifier/dehumidifier, and the volume of interior air space are needed. This method gives results that...

  6. Constraining the Surficial Liquid Water and Resulting Atmospheric Water Vapor Abundance at Recurring Slope Lineae (RSL) Locations on Mars

    Science.gov (United States)

    Berdis, Jodi; Murphy, Jim; Wilson, Robert John

    2017-10-01

    Possible signatures of atmospheric water vapor arising from Martian Recurring Slope Lineae (RSLs) are investigated in this study. RSLs appear during local spring and summer on downward, equator-facing slopes at southern mid-latitudes (~31-52°S Stillman et al. 2014), and have been linked to liquid water which leaves behind streaks of briny material (McEwen et al. 2011, McEwen et al. 2014). Viking Orbiter Mars Atmospheric Water Detector (VO MAWD) and Mars Global Surveyor Thermal Emission Spectrometer (MGS TES) derived atmospheric water vapor abundance values are interrogated to determine whether four RSL locations at southern mid-latitudes (Palikir Crater, Hale Crater, Horowitz Crater, Coprates Chasma) exhibit episodic, enhanced local atmospheric water vapor abundance during southern spring and summer (Ls = 180-360°) when RSLs are observed to develop (Stillman et al. 2014, Ojha et al. 2015). Significant water vapor signals at these locations might reveal RSLs as the source of the enhanced water vapor. Detected atmospheric water vapor signals would expand upon current knowledge of RSLs, whereas non-detection could provide upper limits on RSL water source content. In order to assess how much surficial RSL water would be required to produce a detectable signal, we utilize the high spatial resolution Geophysical Fluid Dynamics Laboratory Mars Climate General Circulation Model to simulate the evaporation of RSL-producing surface water and quantify the magnitude and temporal duration of water vapor content that might be anticipated in response to inferred RSL surface water release. Finally, we will assess the ability of past and future orbiter-based instruments to detect such water vapor quantities.

  7. Distribution of binding energies of a water molecule in the water liquid-vapor interface

    Energy Technology Data Exchange (ETDEWEB)

    Chempath, Shaji [Los Alamos National Laboratory; Pratt, Lawrence R [TULANE UNIV

    2008-01-01

    Distributions of binding energies of a water molecule in the water liquid-vapor interface are obtained on the basis of molecular simulation with the SPC/E model of water. These binding energies together with the observed interfacial density profile are used to test a minimally conditioned Gaussian quasi-chemical statistical thermodynamic theory. Binding energy distributions for water molecules in that interfacial region clearly exhibit a composite structure. A minimally conditioned Gaussian quasi-chemical model that is accurate for the free energy of bulk liquid water breaks down for water molecules in the liquid-vapor interfacial region. This breakdown is associated with the fact that this minimally conditioned Gaussian model would be inaccurate for the statistical thermodynamics of a dilute gas. Aggressive conditioning greatly improves the performance of that Gaussian quasi-chemical model. The analogy between the Gaussian quasi-chemical model and dielectric models of hydration free energies suggests that naive dielectric models without the conditioning features of quasi-chemical theory will be unreliable for these interfacial problems. Multi-Gaussian models that address the composite nature of the binding energy distributions observed in the interfacial region might provide a mechanism for correcting dielectric models for practical applications.

  8. Isotopic Controls of Rainwater and Water Vapor on Mangrove Leaf Water and Lipid Biomarkers

    Science.gov (United States)

    Ladd, N.; Wolfshorndl, M.; Sachs, J. P.

    2015-12-01

    Hydrogen isotope ratios (2H/1H or δ2H) of sedimentary mangrove lipid biomarkers can be used as a proxy of past salinity and water isotopes. This approach is based on the observation that apparent 2H/1H fractionation between surface water and mangrove lipids increases with surface water salinity in six species of mangroves with different salt management strategies growing at sites spanning a range of relative humidities throughout Australia and Micronesia. In order to more robustly apply mangrove lipid δ2H as a paleoclimate proxy, we investigated the cause of the correlation between apparent 2H fractionation and salinity. We present results from two related experiments that assessed controls on isotopes of mangrove leaf water, the direct source of hydrogen in lipids: (1) Measurements of natural δ2H in precipitation, surface water, and mangrove tissue water from a series of lakes with varying salinity and water isotope composition in Palau, and (2) measurements of mangrove tissue water and treatment water from a controlled simulation in which mangroves were treated with artificial rain of varying isotopic composition. Rainwater 2H/1H fluctuations of 30‰ over a one-month period explain up to 65% of the variance in leaf water δ2H for Bruguiera gymnorhiza mangroves from Palau despite lake water isotope differences among sites of up to 35‰. This indicates that in humid tropical settings, leaf water isotopes are more closely related to those of precipitation and water vapor than to those of lake surface water, explaining the observed change in apparent fractionation in B. gymnorhiza lipids with salinity. The relationship between leaf water and rainwater isotopes may be due to either equilibration of leaf water with water vapor in the nearly saturated air or direct foliar uptake of rain and/or dew. Foliar uptake is an important water source for many plants, but has not been documented in mangroves. We tested the capacity for mangroves to perform this function by

  9. Interannual variation of water isotopologues at Vostok indicates a contribution from stratospheric water vapor.

    Science.gov (United States)

    Winkler, Renato; Landais, Amaelle; Risi, Camille; Baroni, Melanie; Ekaykin, Alexey; Jouzel, Jean; Petit, Jean Robert; Prie, Frederic; Minster, Benedicte; Falourd, Sonia

    2013-10-29

    Combined measurements of water isotopologues of a snow pit at Vostok over the past 60 y reveal a unique signature that cannot be explained only by climatic features as usually done. Comparisons of the data using a general circulation model and a simpler isotopic distillation model reveal a stratospheric signature in the (17)O-excess record at Vostok. Our data and theoretical considerations indicate that mass-independent fractionation imprints the isotopic signature of stratospheric water vapor, which may allow for a distinction between stratospheric and tropospheric influences at remote East Antarctic sites.

  10. Preconditioning of the YSZ-NiO Fuel Cell Anode in Hydrogenous Atmospheres Containing Water Vapor

    Science.gov (United States)

    Vasyliv, Bogdan; Podhurska, Viktoriya; Ostash, Orest

    2017-04-01

    The YSZ-NiO ceramics for solid oxide fuel cells (SOFCs) anode have been investigated. A series of specimens were singly reduced in a hydrogenous atmosphere (Ar-5 vol% H2 mixture) at 600 °C under the pressure of 0.15 MPa or subjected to `reduction in the mixture-oxidation in air' (redox) cycling at 600 °C. The YSZ-Ni cermets formed in both treatment conditions were then aged in `water vapor in Ar-5 vol% H2 mixture' atmosphere at 600 °C under the pressure of 0.15 MPa. Additionally, the behaviour of the as-received material in this atmosphere was studied. It was revealed that small amount of water vapor in Ar-5 vol% H2 mixture (water vapor pressure below 0.03 MPa) does not affect the reduction of the nickel phase in the YSZ-NiO ceramics, but causes some changes in the YSZ-Ni cermet structure. In particular, nanopore growth in tiny Ni particles takes place. At higher concentration of water vapor in the mixture (water vapor pressure above 0.03-0.05 MPa), converse changes in the kinetics of reduction occur. The best physical and mechanical properties were revealed for the material treated by redox cycling after holding at 600 °C in water depleted gas mixture. The dual effect of water vapor on nickel-zirconia anode behaviour is discussed basing on scanning electron microscopy analysis data, material electrical conductivity, and strength.

  11. The Effect of Water Vapor on the Thermal Decomposition of Pyrite in N2 Atmosphere

    Directory of Open Access Journals (Sweden)

    Nesrin BOYABAT

    2009-03-01

    Full Text Available In this study, the effect of water vapor on the thermal decomposition of pyrite mineral in nitrogen atmosphere has been investigated in a horizontal tube furnace. Temperature, time and water vapor concentration were used as experimental parameters. According to the data obtained at nitrogen/ water vapor environment, it was observed that the water vapor on the decomposition of pyrite increased the decomposition rate. The decomposition reaction is well represented by the "shrinking core" model and can be divided into two regions with different rate controlling step. The rate controlling steps were determined from the heat transfer through the gas film for the low conversions, while it was determined from the mass transfer through product ash layer for the high conversions. The activation energies of this gas and ash film mechanisms were found to be 77 and 81 kJ/mol-1, respectively.

  12. Raman Lidar Calibration for the DMSP SSM/T-2 Microwave Water Vapor Sensor

    National Research Council Canada - National Science Library

    Wessel, J

    2000-01-01

    Campaigns were conducted at the Pacific Missile Range Facility, Barking Sands, Kauai, investigating Raman lidar as a method to improve calibration of the DMSP SSM/T-2 microwave water vapor profiling instrument...

  13. Nimbus-6/SCAMS Level 2 Water Vapor and Temperature V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The Nimbus-6 Scanning Microwave Spectrometer (SCAMS) Level 2 data product contains water vapor and temperature profiles. The SCAMS was designed to map tropospheric...

  14. GPM GROUND VALIDATION AEROSOL AND WATER VAPOR LIDAR QUICKLOOKS GCPEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation Aerosol and Water Vapor Lidar Quicklooks GCPEx dataset contains imagery generated from the GPM Cold-season Precipitation Experiment (GCPEx)...

  15. Nanostructure Fabrication by Electron-Beam-Induced Deposition with Metal Carbonyl Precursor and Water Vapor

    Science.gov (United States)

    Takeguchi, Masaki; Shimojo, Masayuki; Furuya, Kazuo

    2007-09-01

    Nanorod fabrication is performed by electron beam induced deposition (EBID) with iron carbonyl [Fe(CO)5] and tungsten carbonyl [W(CO)6] precursors. The effects of water vapor addition to each metal carbonyl on the microstructure and composition of the obtained nanorods are studied. Normally, EBID-fabricated metal nanorods consist of an amorphous phase containing a considerable amount of carbon. However, it is found that water vapor addition to iron carbonyl can effectively reduce the carbon content of the nanorods and induce the formation of carbon-free crystalline Fe3O4 nanorods with increasing partial pressure ratio of water vapor to iron carbonyl. In contrast, for tungsten carbonyl, water vapor addition has no obvious effect on carbon content reduction. The obtained nanorods consist of a carbon-rich amorphous matrix containing tungsten oxide nanocrystals inside.

  16. MLS/Aura Level 2 Water Vapor (H2O) Mixing Ratio V004

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2H2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for water vapor derived from radiances measured primarily by the 190 GHz radiometer. The current...

  17. MLS/Aura L2 Water Vapor (H2O) Mixing Ratio V002

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2H2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for water vapor derived from radiances measured primarily by the 190 GHz radiometer. The current...

  18. SAFARI 2000 AOT and Column Water Vapor, Kalahari Transect, Wet Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The data presented here include the aerosol optical thickness (AOT) and column water vapor measurements taken at sites along the Kalahari Transect using a...

  19. Solid State Transmitters for Water Vapor and Ozone DIAL Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We have developed a common architecture for laser transmitters that address requirements for water vapor as well as ground and airborne ozone lidar systems. Our...

  20. Scanning Multichannel Microwave Radiometer (SMMR) Monthly Mean Integrated Water Vapor (IWV) By Prabhakara

    Data.gov (United States)

    National Aeronautics and Space Administration — SMMR_IWV_PRABHAKARA data are Special Multichannel Microwave Radiometer (SMMR) Monthly Mean Integrated Water Vapor (IWV) data by Prabhakara.The Scanning Multichannel...

  1. MODIS/Aqua Temperature and Water Vapor Profiles 5-Min L2 Swath 5km - NRT

    Data.gov (United States)

    National Aeronautics and Space Administration — The level-2 MODIS Temperature and Water Vapor Profile Product MYD07_L2 consists of 30 gridded parameters related to atmospheric stability, atmospheric temperature...

  2. Solid State Transmitters for Water Vapor and Ozone DIAL Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The focus of this Select Phase II program is to build and deliver laser components both for airborne water vapor and ozone DIAL systems. Specifically, Fibertek...

  3. Lidar Atmopheric Sensing Experiment (LASE) Data Obtained During the ARM-FIRE Water Vapor Experiment (AFWEX)

    Data.gov (United States)

    National Aeronautics and Space Administration — LASE_AFWEX data are Lidar Atmospheric Sensing Experiment water vapor and aerosol data measurements taken during ARM-FIRE (Atmospheric Radiation Measurement - First...

  4. EPA Method 245.1: Determination of Mercury in Water by Cold Vapor Atomic Absorption Spectrometry

    Science.gov (United States)

    SAM lists this method for preparation and analysis of aqueous liquid and drinking water samples. This method will determine mercuric chloride and methoxyethylmercuric acetate as total mercury using cold vapor atomic absorption spectrometry.

  5. Polymer functionalized nanostructured porous silicon for selective water vapor sensing at room temperature

    Science.gov (United States)

    Dwivedi, Priyanka; Das, Samaresh; Dhanekar, Saakshi

    2017-04-01

    This paper highlights the surface treatment of porous silicon (PSi) for enhancing the sensitivity of water vapors at room temperature. A simple and low cost technique was used for fabrication and functionalization of PSi. Spin coated polyvinyl alcohol (PVA) was used for functionalizing PSi surface. Morphological and structural studies were conducted to analyze samples using SEM and XRD/Raman spectroscopy respectively. Contact angle measurements were performed for assessing the wettability of the surfaces. PSi and functionalized PSi samples were tested as sensors in presence of different analytes like ethanol, acetone, isopropyl alcohol (IPA) and water vapors in the range of 50-500 ppm. Electrical measurements were taken from parallel aluminium electrodes fabricated on the functionalized surface, using metal mask and thermal evaporation. Functionalized PSi sensors in comparison to non-functionalized sensors depicted selective and enhanced response to water vapor at room temperature. The results portray an efficient and selective water vapor detection at room temperature.

  6. Fuel for cyclones: How the water vapor budget of a hurricane depends on its motion

    CERN Document Server

    Makarieva, Anastassia M; Nefiodov, Andrei V; Chikunov, Alexander V; Sheil, Douglas; Nobre, Antonio D; Li, Bai-Lian

    2016-01-01

    Tropical cyclones are fueled by water vapor. Here we estimate the oceanic evaporation within an Atlantic hurricane to be less than one sixth of the total moisture flux precipitating over the same area. So how does the hurricane get the remaining water vapor? Our analysis of TRMM rainfall, MERRA atmospheric moisture and hurricane translation velocities suggests that access to water vapor relies on the hurricane's motion -- as it moves through the atmosphere, the hurricane consumes the water vapor it encounters. This depletion of atmospheric moisture by the hurricane leaves a "dry footprint" of suppressed rainfall in its wake. The thermodynamic efficiency of hurricanes -- defined as kinetic energy production divided by total latent heat release associated with the atmospheric moisture supply -- remains several times lower than Carnot efficiency even in the most intense hurricanes. Thus, maximum observed hurricane power cannot be explained by the thermodynamic Carnot limit.

  7. Distribution Analysis of Multi GNSS Slant Delays and Simulated Water Vapor Tomography in Yangtze River Delta

    Directory of Open Access Journals (Sweden)

    WANG Wei

    2016-02-01

    Full Text Available Currently, the GNSS network of Yangtze River delta has being applied to monitor the water vapor above this region and research water vapor tomography. Studies have shown that the dictances between stations are large and inhomogeneous, that will make it difficult to get the high tomography precision. Therefore, a simulation test of multi GNSS observations on tomography is introduced. The multi GNSS observations are more homogeneous in spatial distribution than a single positioning system, which can reduce the space rate of the grid, especially increase the number of the grid with information at middle and high layers. The multi GNSS observation can provide more and better water vapor information which can patch up deficiency of a single positioning system. A simulated water vapor tomography is carried out, and the result shows that the multi GNSS observations could improve the accuracy of tomography, especially above the 5 km height layer of the atmosphere.

  8. Liquid-phase and vapor-phase dehydration of organic/water solutions

    Science.gov (United States)

    Huang, Yu [Palo Alto, CA; Ly, Jennifer [San Jose, CA; Aldajani, Tiem [San Jose, CA; Baker, Richard W [Palo Alto, CA

    2011-08-23

    Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.

  9. MLS/Aura L2 Water Vapor (H2O) Mixing Ratio V003

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2H2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for water vapor derived from radiances measured primarily by the 190 GHz radiometer. The current...

  10. Optimization of GPS water vapor tomography technique with radiosonde and COSMIC historical data

    Directory of Open Access Journals (Sweden)

    S. Ye

    2016-09-01

    Full Text Available The near-real-time high spatial resolution of atmospheric water vapor distribution is vital in numerical weather prediction. GPS tomography technique has been proved effectively for three-dimensional water vapor reconstruction. In this study, the tomography processing is optimized in a few aspects by the aid of radiosonde and COSMIC historical data. Firstly, regional tropospheric zenith hydrostatic delay (ZHD models are improved and thus the zenith wet delay (ZWD can be obtained at a higher accuracy. Secondly, the regional conversion factor of converting the ZWD to the precipitable water vapor (PWV is refined. Next, we develop a new method for dividing the tomography grid with an uneven voxel height and a varied water vapor layer top. Finally, we propose a Gaussian exponential vertical interpolation method which can better reflect the vertical variation characteristic of water vapor. GPS datasets collected in Hong Kong in February 2014 are employed to evaluate the optimized tomographic method by contrast with the conventional method. The radiosonde-derived and COSMIC-derived water vapor densities are utilized as references to evaluate the tomographic results. Using radiosonde products as references, the test results obtained from our optimized method indicate that the water vapor density accuracy is improved by 15 and 12 % compared to those derived from the conventional method below the height of 3.75 km and above the height of 3.75 km, respectively. Using the COSMIC products as references, the results indicate that the water vapor density accuracy is improved by 15 and 19 % below 3.75 km and above 3.75 km, respectively.

  11. Is There Evidence of Convectively Injected Water Vapor in the Lowermost Stratosphere Over Boulder, Colorado?

    Science.gov (United States)

    Hurst, D. F.; Rosenlof, K. H.; Davis, S. M.; Hall, E. G.; Jordan, A. F.

    2014-12-01

    Anderson et al. (2012) reported the frequent presence of convectively injected water vapor in the lowermost stratosphere over North America during summertime, based on aircraft measurements. They asserted that enhanced catalytic ozone destruction within these wet stratospheric air parcels presents a concern for UV dosages in populated areas, especially if the frequency of deep convective events increases. Schwartz et al.(2013) analyzed 8 years of more widespread Aura Microwave Limb Sounder (MLS) measurements of lower stratospheric water vapor over North America and concluded that anomalously wet (>8 ppm) air parcels were present only 2.5% of the time during July and August. However, given the 3-km vertical resolution of MLS water vapor retrievals in the lowermost stratosphere, thin wet layers deposited by overshooting convection may be present but not readily detectable by MLS. Since 1980 the balloon-borne NOAA frost point hygrometer (FPH) has produced nearly 400 high quality water vapor profiles over Boulder, Colorado, at 5-m vertical resolution from the surface to the middle stratosphere. The 34-year record of high-resolution FPH profiles obtained over Boulder during summer months is evaluated for evidence of convectively injected water vapor in the lowermost stratosphere. A number of approaches are used to assess the contributions of deep convection to the Boulder stratospheric water vapor record. The results are compared to those based on MLS profiles over Boulder and the differences are discussed. Anderson, J. G., D. M. Wilmouth, J. B. Smith, and D. S. Sayres (2012), UV dosage levels in summer: Increased risk of ozone loss from convectively injected water vapor, Science, 337(6096), 835-839, doi:10.1126/science.1222978. Schwartz, M. J., W. G. Read, M. L. Santee, N. J. Livesey, L. Froidevaux, A. Lambert, and G. L. Manney (2013), Convectively injected water vapor in the North American summer lowermost stratosphere, Geophys. Res. Lett., 40, 2316-2321, doi:10

  12. Effects of altitude on transpiration, leaf vapor pressure deficit and leaf water potential in oriental beech

    Directory of Open Access Journals (Sweden)

    Fatih Bayraktar

    2015-04-01

    Full Text Available This study was designed to determine the effect of altitude on transpiration, leaf vapor pressure deficit and leaf water potential in oriental beech (Fagus orientalis Lipsky. The study area was located in Ortaköy, Artvin, and the experimental area had the same soil structure and aspect. The study showed that transpiration and leaf vapor pressure deficit increased but leaf water potential decreased by altitudinal gradient

  13. Water Vapor Permeability of Edible Films Based on Improved Cassava (Manihot esculenta Crantz) Native Starches

    OpenAIRE

    Adjouman, Yao Désiré; Nindjin, Charlemagne; Tetchi, F.Achille; Dalcq, Anne-Catherine; Amani, N.Georges; Sindic, Marianne

    2017-01-01

    Starch is used in the production of edible biodegradable packaging as an attractive alternative to synthetic polymers because it is a natural biopolymer of low cost and high availability. Many studies have been carried out on films based on cassava starch and the results show that these have good flexibility and low water vapor permeability. This present research was conducted to analyse the effect of glycerol, peanut oil and soybean lecithin on the water vapor permeability (WVP) of edible fi...

  14. The Potential of Water Vapor & Precipitation Estimation with a Differential-frequency Radar

    Science.gov (United States)

    Meneghini, Robert; Liao, Liang; Tian, Lin

    2006-01-01

    In the presence of rain, the radar return powers from a three-frequency radar, with center frequency at 22.235 GHz and upper and lower frequencies chosen with equal water vapor absorption coefficients, can be used to estimate water vapor density and parameters of the precipitation. A linear combination of differential measurements between the center and lower frequencies on one hand and the upper and lower frequencies on the other provide an estimate of differential water vapor absorption. Conversely, the difference in radar reflectivity factors (in dB) between the upper and lower frequencies is independent of water vapor absorption and can be used to estimate the median mass diameter of the hydrometeors. For a down-looking radar, path-integrated estimates of water vapor absorption may be possible under rain-free as well as raining conditions by using the surface returns at the three frequencies. Cross-talk or interference between the precipitation and water vapor estimates depends on the frequency separation of the channels as well as on the phase state and the median mass diameter of the hydrometeors. Simulations of the retrieval of water vapor absorption show that the largest source of variability arises from the variance in the measured radar return powers while the largest biases occur in the mixed-phase region. Use of high pulse repetition frequencies and signal whitening methods may be needed to obtain the large number of independent samples required. Measurements over a fractional bandwidth, defined as the ratio of the difference between the upper and lower frequencies to the center frequency, up to about 0.2 should be passible in a differential frequency mode, where a single transceiver and antenna are used. Difficulties in frequency allocation may require alternative choices of frequency where the water vapor absorptions at the low and high frequencies are unequal. We consider the degradation in the retrieval accuracy when the frequencies are not optimum.

  15. Investigating the source, transport, and isotope composition of water vapor in the planetary boundary layer

    Directory of Open Access Journals (Sweden)

    T. J. Griffis

    2016-04-01

    Full Text Available Increasing atmospheric humidity and convective precipitation over land provide evidence of intensification of the hydrologic cycle – an expected response to surface warming. The extent to which terrestrial ecosystems modulate these hydrologic factors is important to understand feedbacks in the climate system. We measured the oxygen and hydrogen isotope composition of water vapor at a very tall tower (185 m in the upper Midwest, United States, to diagnose the sources, transport, and fractionation of water vapor in the planetary boundary layer (PBL over a 3-year period (2010 to 2012. These measurements represent the first set of annual water vapor isotope observations for this region. Several simple isotope models and cross-wavelet analyses were used to assess the importance of the Rayleigh distillation process, evaporation, and PBL entrainment processes on the isotope composition of water vapor. The vapor isotope composition at this tall tower site showed a large seasonal amplitude (mean monthly δ18Ov ranged from −40.2 to −15.9 ‰ and δ2Hv ranged from −278.7 to −113.0 ‰ and followed the familiar Rayleigh distillation relation with water vapor mixing ratio when considering the entire hourly data set. However, this relation was strongly modulated by evaporation and PBL entrainment processes at timescales ranging from hours to several days. The wavelet coherence spectra indicate that the oxygen isotope ratio and the deuterium excess (dv of water vapor are sensitive to synoptic and PBL processes. According to the phase of the coherence analyses, we show that evaporation often leads changes in dv, confirming that it is a potential tracer of regional evaporation. Isotope mixing models indicate that on average about 31 % of the growing season PBL water vapor is derived from regional evaporation. However, isoforcing calculations and mixing model analyses for high PBL water vapor mixing ratio events ( >  25 mmol mol−1

  16. Investigating the source, transport, and isotope composition of water vapor in the planetary boundary layer

    Science.gov (United States)

    Griffis, Timothy J.; Wood, Jeffrey D.; Baker, John M.; Lee, Xuhui; Xiao, Ke; Chen, Zichong; Welp, Lisa R.; Schultz, Natalie M.; Gorski, Galen; Chen, Ming; Nieber, John

    2016-04-01

    Increasing atmospheric humidity and convective precipitation over land provide evidence of intensification of the hydrologic cycle - an expected response to surface warming. The extent to which terrestrial ecosystems modulate these hydrologic factors is important to understand feedbacks in the climate system. We measured the oxygen and hydrogen isotope composition of water vapor at a very tall tower (185 m) in the upper Midwest, United States, to diagnose the sources, transport, and fractionation of water vapor in the planetary boundary layer (PBL) over a 3-year period (2010 to 2012). These measurements represent the first set of annual water vapor isotope observations for this region. Several simple isotope models and cross-wavelet analyses were used to assess the importance of the Rayleigh distillation process, evaporation, and PBL entrainment processes on the isotope composition of water vapor. The vapor isotope composition at this tall tower site showed a large seasonal amplitude (mean monthly δ18Ov ranged from -40.2 to -15.9 ‰ and δ2Hv ranged from -278.7 to -113.0 ‰) and followed the familiar Rayleigh distillation relation with water vapor mixing ratio when considering the entire hourly data set. However, this relation was strongly modulated by evaporation and PBL entrainment processes at timescales ranging from hours to several days. The wavelet coherence spectra indicate that the oxygen isotope ratio and the deuterium excess (dv) of water vapor are sensitive to synoptic and PBL processes. According to the phase of the coherence analyses, we show that evaporation often leads changes in dv, confirming that it is a potential tracer of regional evaporation. Isotope mixing models indicate that on average about 31 % of the growing season PBL water vapor is derived from regional evaporation. However, isoforcing calculations and mixing model analyses for high PBL water vapor mixing ratio events ( > 25 mmol mol-1) indicate that regional evaporation can account

  17. Portable device for generation of ultra-pure water vapor feeds

    Science.gov (United States)

    Velin, P.; Stenman, U.; Skoglundh, M.; Carlsson, P.-A.

    2017-11-01

    A portable device for the generation of co-feeds of water vapor has been designed, constructed, and evaluated for flexible use as an add-on component to laboratory chemical reactors. The vapor is formed by catalytic oxidation of hydrogen, which benefits the formation of well-controlled minute concentrations of ultra-pure water. Analysis of the effluent stream by on-line mass spectrometry and Fourier transform infrared spectroscopy confirms that water vapor can be, with high precision, generated both rapidly and steadily over extended periods in the range of 100 ppm to 3 vol. % (limited by safety considerations) using a total flow of 100 to 1500 ml/min at normal temperature and pressure. Further, the device has been used complementary to a commercial water evaporator and mixing system to span water concentrations up to 12 vol. %. Finally, an operando diffuse reflective infrared Fourier transform spectroscopic measurement of palladium catalysed methane oxidation in the absence and presence of up to 1.0 vol. % water has been carried out to demonstrate the applicability of the device for co-feeding well-controlled low concentrations of water vapor to a common type of spectroscopic experiment. The possibilities of creating isotopically labeled water vapor as well as using tracer gases for dynamic experiments are discussed.

  18. Controls on water vapor isotopes over Roorkee, India: Impact of convective activities and depression systems

    Science.gov (United States)

    Saranya, P.; Krishan, Gopal; Rao, M. S.; Kumar, Sudhir; Kumar, Bhishm

    2018-02-01

    The study evaluates the water vapor isotopic compositions and its controls with special reference to Indian Summer Monsoon (ISM) season at Roorkee, India. Precipitation is usually a discrete event spatially and temporally in this part of the country, therefore, the information provided is limited, while, the vapors have all time availability and have a significant contribution in the hydrological cycle locally or over a regional scale. Hence for understanding the processes altering the various sources, its isotopic signatures were studied. The Isotope Water Vapour Line (Iso Val) was drawn together with the Global Meteoric Water Line (GMWL) and the best fit line was δD = 5.42 * δ18O + 27.86. The precipitation samples were also collected during the study period and were best fitted with δD = 8.20(±0.18) * δ18O + 9.04(±1.16) in the Local Meteoric Water Line (LMWL). From the back trajectory analysis of respective vapor samples, it is unambiguous that three major sources viz; local vapor, western disturbance and monsoon vapor are controlling the fate of moisture over Roorkee. The d-excess in ground-level vapor (GLV) reveals the supply of recycled moisture from continental water bodies and evapo-transpiration as additional moisture sources to the study area. The intensive depletion in isotopic ratios was associated with the large-scale convective activity and low-pressure/cyclonic/depression systems formed over Bay of Bengal.

  19. Colorimetric Detection of Water Vapor Using Metal-Organic Framework Composites.

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    Purpose: Water vapor trapped in encapsulation materials or enclosed volumes leads to corrosion issues for critical NW components. Sandia National Laboratories has created a new diagnostic to indicate the presence of water in weapon systems. Impact: Component exposure to water now can be determined instantly, without need for costly, time-consuming analytical methods.

  20. Stable isotopic variations of water vapor on the winter coastal area in Korea

    Science.gov (United States)

    Lee, Jeonghoon; Lee, Songyi; Han, Yeongcheol; Do Hur, Soon

    2017-04-01

    Studies of isotopic compositions of precipitation in Korea have been conducted for groundwater mixing and sources and residence time of water. Unravelling of water vapor isotopes will be very helpful in explaining the sources of moisture. In this work, we first present isotopic compositions of water vapor over western part of Korea in winter between December 2015 and February 2016. We collected the samples of water vapor isotopes by a cryogenic method with impingers and liquid nitrogen. We captured the water vapor for 4 to 6 hours, depending on humidity and collected 54 samples in total. The samples were analyzed by a Picarro L2130-i and the precisions were 0.06‰ and 0.7‰ for oxygen and hydrogen, respectively. The isotopic compositions of water vapor ranged from -34.04‰ to -15.27‰ for oxygen and from -221.9‰ to -100.2‰ for hydrogen. The deuterium excess (d=δD-8*δ18O) was between 17.4 and 44.0 in permil. Both air temperature (T, δ18O=0.57*T-25.5, R2=0.46) and relative humidity (RH, δ18O=0.18*RH-35.9, R2=0.38) were positively correlated with the water vapor isotopes. This is not consistent with the fact that precipitation isotopes are correlated with only temperate in winter Eastern Asia. We expect that the water vapor isotopes will be an important role to understand the origin and pathway of moistures over the Eastern Asia.

  1. Effects of water vapor on flue gas conditioning in the electric fields with corona discharge

    Energy Technology Data Exchange (ETDEWEB)

    Liqiang, QI, E-mail: qi_liqiang@163.com; Yajuan, Zhang

    2013-07-15

    Highlights: • The influence mechanism of water vapor humidification on SO{sub 2} oxidation was analyzed. •The effects of water vapor on the specific resistance in fly ash in ESPs were reported. • The effects of water vapor on the size distribution and specific surface area of fly ash were discussed. • The adhesive characteristic of fly ash in different water vapor was experimented. -- Abstract: Sulfur dioxide (SO{sub 2}) removal via pulsed discharge nonthermal plasma in the absence of ammonia was investigated to determine how electrostatic precipitators (ESPs) can effectively collect particulate matter less than 2.5 μm in diameter from flue gas. SO{sub 2} removal increased as water vapor concentration increased. In a wet-type plasma reactor, directing a gas-phase discharge plasma toward the water film surface significantly enhanced the liquid-phase oxidation of HSO{sub 3}{sup −} to SO{sub 4}{sup 2−}. Comparisons of various absorbents revealed that the hydroxyl radical is a key factor in plasma-induced liquid-phase reactions. The resistivity, size distribution, and cohesive force of fly ash at different water vapor contents were measured using a Bahco centrifuge, which is a dust electrical resistivity test instrument, as well as a cohesive force test apparatus developed by the researchers. When water vapor content increased by 5%, fly ash resistivity in flue gas decreased by approximately two orders of magnitude, adhesive force and size increased, and specific surface area decreased. Therefore, ESP efficiency increased.

  2. Measurement of Vapor Flow As an Important Source of Water in Dry Land Eco-Hydrology

    Science.gov (United States)

    Wang, Z.; He, Z.; Wang, Y.; Gao, Z.; Hishida, K.

    2014-12-01

    When the temperature of land surface is lower than that of air and deeper soils, water vapor gathers toward the ground surface where dew maybe formed depending on the prevailing dew point and wind speed. Some plants are able to absorb the dew and vapor flow while the soil can readily absorb both. Certain animals such as desert beetles and ants harvest the dew or fog for daily survival. Recently, it is also realized that the dew and vapor flow can be a life-saving amount of water for plant survival at the driest seasons of the year in arid and semi-arid regions. Researches are conducted to quantify the amount of near-surface vapor flow in arid and semi-arid regions in China and USA. Quantitative leaf water absorption and desorption functions were derived based on laboratory experiments. Results show that plant leaves absorb and release water at different speeds depending on species and varieties. The "ideal" native plants in the dry climates can quickly absorb water and slowly release it. This water-holding capacity of plant is characterized by the absorption and desorption functions derived for plant physiology and water balance studies. Field studies are conducted to measure the dynamic vapor flow movements from the atmosphere and the groundwater table to soil surface. Results show that dew is usually formed on soil and plant surfaces during the daily hours when the temperature gradients are inverted toward the soil surface. The amount of dew harvested using gravels on the soil surface was enough to support water melon agriculture on deserts. The vapor flow can be effectively intercepted by artificially seeded plants in semi-arid regions forming new forests. New studies are attempted to quantify the role of vapor flow for the survival of giant sequoias in the southern Sierra Nevada Mountains of California.

  3. SEPARATION OF WATER VAPORS FROM AIR BY SORPTION ON SOME COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    OANA HAUTĂ

    2014-01-01

    Full Text Available This work presents an experimental investigation of the kinetics of water vapor sorption on two composites synthesized by impregnating activated carbon and activated alumina respectively with lithium bromide (named as MCA2 and MCC2 respectively. The obtained results showed an increase in water amount adsorbed on both composite materials. Due to different chemical natures of the host matrices, the water sorption kinetics on MCC2 is faster compared to that of MCA2. The presence of calcium chloride instead of lithium bromide in alumina pores will determine a shorter breakthrough time and a higher adsorption rate of water vapors.

  4. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere.

    Science.gov (United States)

    Gorski, Galen; Strong, Courtenay; Good, Stephen P; Bares, Ryan; Ehleringer, James R; Bowen, Gabriel J

    2015-03-17

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry.

  5. The observed day-to-day variability of Mars water vapor

    Science.gov (United States)

    Jakosky, Bruce M.; Lapointe, Michael R.; Zurek, Richard W.

    1987-01-01

    The diurnal variability of atmospheric water vapor as derived from the Viking MAWD data is discussed. The detection of day to day variability of atmospheric water would be a significant finding since it would place constraints on the nature of surface reservoirs. Unfortunately, the diurnal variability seen by the MAWD experiment is well correlated with the occurrence of dust and/or ice hazes, making it difficult to separate real variations from observational effects. Analysis of the day to day variability of water vapor in the Martian atmosphere suggests that the observations are, at certain locations and seasons, significantly affected by the presence of water-ice hazes. Because such effects are generally limited to specific locations, such as Tharsis, Lunae Planum, and the polar cap edge during the spring, the seasonal and latitudinal trends in water vapor that have been previously reported are not significantly affected.

  6. Reduction of Legionella spp. in Water and in Soil by a Citrus Plant Extract Vapor

    Science.gov (United States)

    Kurzbach, Elena; Score, Jodie; Tejpal, Jyoti; Chi Tangyie, George; Phillips, Carol

    2014-01-01

    Legionnaires' disease is a severe form of pneumonia caused by Legionella spp., organisms often isolated from environmental sources, including soil and water. Legionella spp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred, Legionella is particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml−1 on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii, and an intra-amoebal culture of Legionella pneumophila (water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml−1 reduction in Legionella spp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water was L. pneumophila, with a 4-log cells ml−1 reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controlling Legionella spp. from environmental sources. PMID:25063652

  7. A New Technique for the Retrieval of Near Surface Water Vapor Using DIAL Measurements

    Science.gov (United States)

    Ismail, Syed; Kooi, Susan; Ferrare, Richard; Winker, David; Hair, Johnathan; Nehrir, Amin; Notari, Anthony; Hostetler, Chris

    2015-01-01

    Water vapor is one of the most important atmospheric trace gas species and influences radiation, climate, cloud formation, surface evaporation, precipitation, storm development, transport, dynamics, and chemistry. For improvements in NWP (numerical weather prediction) and climate studies, global water vapor measurements with higher accuracy and vertical resolution are needed than are currently available. Current satellite sensors are challenged to characterize the content and distribution of water vapor in the Boundary Layer (BL) and particularly near the first few hundred meters above the surface within the BL. These measurements are critically needed to infer surface evaporation rates in cloud formation and climate studies. The NASA Langley Research Center Lidar Atmospheric Sensing Experiment (LASE) system, which uses the Differential Absorption Lidar (DIAL) technique, has demonstrated the capability to provide high quality water vapor measurements in the BL and across the troposphere. A new retrieval technique is investigated to extend these DIAL water vapor measurements to the surface. This method uses signals from both atmospheric backscattering and the strong surface returns (even over low reflectivity oceanic surfaces) using multiple gain channels to cover the large signal dynamic range. Measurements can be made between broken clouds and in presence of optically thin cirrus. Examples of LASE measurements from a variety of conditions encountered during NASA hurricane field experiments over the Atlantic Ocean are presented. Comparisons of retrieved water vapor profiles from LASE near the surface with dropsonde measurements show very good agreement. This presentation also includes a discussion of the feasibility of developing space-based DIAL capability for high resolution water vapor measurements in the BL and above and an assessment of the technology needed for developing this capability.

  8. Reduction of Legionella spp. in water and in soil by a citrus plant extract vapor.

    Science.gov (United States)

    Laird, Katie; Kurzbach, Elena; Score, Jodie; Tejpal, Jyoti; Chi Tangyie, George; Phillips, Carol

    2014-10-01

    Legionnaires' disease is a severe form of pneumonia caused by Legionella spp., organisms often isolated from environmental sources, including soil and water. Legionella spp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred, Legionella is particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml(-1) on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii, and an intra-amoebal culture of Legionella pneumophila (water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml(-1) reduction in Legionella spp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water was L. pneumophila, with a 4-log cells ml(-1) reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controlling Legionella spp. from environmental sources. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  9. Modeling Convection of Water Vapor into the Mid-latitude Summer Stratosphere

    Science.gov (United States)

    Clapp, C.; Leroy, S. S.; Anderson, J. G.

    2016-12-01

    Water vapor in the upper troposphere and lower stratosphere (UTLS) from the tropics to the poles is important both radiatively and chemically. Water vapor is the most important greenhouse gas, and increases in water vapor concentrations in the UTLS lead to cooling at these levels and induce warming at the surface [Forster and Shine, 1999; 2002; Solomon et al., 2010]. Water vapor is also integral to stratospheric chemistry. It is the dominant source of OH in the lower stratosphere [Hanisco et al., 2001], and increases in water vapor concentrations promote stratospheric ozone loss by raising the reactivity of several key heterogeneous reactions as well as by promoting the growth of reactive surface area [Anderson et al., 2012; Carslaw et al., 1995; Carslaw et al., 1997; Drdla and Muller , 2012; Kirk-Davidoff et al., 1999; Shi et al., 2001]. However, the processes that control the distribution and phase of water in this region of the atmosphere are not well understood. This is especially true at mid-latitudes where several different dynamical mechanisms are capable of influencing UTLS water vapor concentrations. The contribution by deep convective storm systems that penetrate into the lower stratosphere is the least well understood and the least well represented in global models because of the small spatial scales and short time scales over which convection occurs. To address this issue, we have begun a modeling study to investigate the convective injection of water vapor from the troposphere into the stratosphere in the mid-latitudes. Fine-scale models have been previously used to simulate convection from the troposphere to the stratosphere [e.g., Homeyer et al., 2014]. Here we employ the Advanced Research Weather and Research Forecasting model (ARW) at 3-km resolution to resolve convection over the mid-western United States during August of 2013 including a storm system observed by SEAC4RS. We assess the transport of water vapor into the stratosphere over the model

  10. Correlation of vapor - liquid equilibrium data for acetic acid - isopropanol - water - isopropyl acetate mixtures

    Directory of Open Access Journals (Sweden)

    B. A. Mandagarán

    2006-03-01

    Full Text Available A correlation procedure for the prediction of vapor - liquid equilibrium of acetic acid - isopropanol - water - isopropyl acetate mixtures has been developed. It is based on the NRTL model for predicting liquid activity coefficients, and on the Hayden-O'Connell second virial coefficients for predicting the vapor phase of systems containing association components. When compared with experimental data the correlation shows a good agreement for binary and ternary data. The correlation also shows good prediction for reactive quaternary data.

  11. Vaporization order and burning efficiency of crude oils during in-situ burning on water

    DEFF Research Database (Denmark)

    van Gelderen, Laurens; Malmquist, Linus M.V.; Jomaas, Grunde

    2017-01-01

    In order to improve the understanding of the burning efficiency and its observed size dependency of in-situ burning of crude oil on water, the vaporization order of the components in crude oils was studied. The vaporization order of such multicomponent fuels was assessed by studying the surface...... scale fires can overcome these heat losses, as they typically have higher burning rates, which increase the heat feedback to the fuel surface and therefore can result in the higher burning efficiencies....

  12. Arctic cyclone water vapor isotopes support past sea ice retreat recorded in Greenland ice.

    Science.gov (United States)

    Klein, Eric S; Cherry, J E; Young, J; Noone, D; Leffler, A J; Welker, J M

    2015-05-29

    Rapid Arctic warming is associated with important water cycle changes: sea ice loss, increasing atmospheric humidity, permafrost thaw, and water-induced ecosystem changes. Understanding these complex modern processes is critical to interpreting past hydrologic changes preserved in paleoclimate records and predicting future Arctic changes. Cyclones are a prevalent Arctic feature and water vapor isotope ratios during these events provide insights into modern hydrologic processes that help explain past changes to the Arctic water cycle. Here we present continuous measurements of water vapor isotope ratios (δ(18)O, δ(2)H, d-excess) in Arctic Alaska from a 2013 cyclone. This cyclone resulted in a sharp d-excess decrease and disproportional δ(18)O enrichment, indicative of a higher humidity open Arctic Ocean water vapor source. Past transitions to warmer climates inferred from Greenland ice core records also reveal sharp decreases in d-excess, hypothesized to represent reduced sea ice extent and an increase in oceanic moisture source to Greenland Ice Sheet precipitation. Thus, measurements of water vapor isotope ratios during an Arctic cyclone provide a critical processed-based explanation, and the first direct confirmation, of relationships previously assumed to govern water isotope ratios during sea ice retreat and increased input of northern ocean moisture into the Arctic water cycle.

  13. Effects of biochar and manure amendments on water vapor sorption in a sandy loam soil

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

    2015-01-01

    properties of soils, especially on water retention at low matric potentials. To overcome this knowledge gap, the effects of combined BC (0 to 100 Mg ha-1) and manure (21 and 42 Mg ha-1) applications on water vapor sorption and specific surface area was investigated for a sandy loam soil. In addition......, potential impacts of BC aging were evaluated. All considered BC-amendment rates led to a distinct increase of water retention, especially for low matric potentials. The observed increases were attributed to a significant increase of soil organic matter contents and specific surface areas in BCamended soils....... Hysteresis of the water vapor sorption isotherms increased with increasing BC application rates. Biochar age did not significantly affect vapor sorption and SSA....

  14. Water vapor permeation and dehumidification performance of poly(vinyl alcohol)/lithium chloride composite membranes

    KAUST Repository

    Bui, Duc Thuan

    2015-10-09

    Thin and robust composite membranes comprising stainless steel scaffold, fine and porous TiO2 and polyvinyl alcohol/lithium chloride were fabricated and studied for air dehumidification application. Higher hydrophilicity, sorption and permeation were observed for membranes with increased lithium chloride content up to 50%. The permeation and sorption properties of the membranes were investigated under different temperatures. The results provided a deeper insight into the membrane water vapor permeation process. It was specifically noted that lithium chloride significantly reduces water diffusion energy barrier, resulting in the change of permeation energy from positive to negative values. Higher water vapor permeance was observed for the membrane with higher LiCl content at lower temperature. The isothermal air dehumidification tests show that the membrane is suitable for dehumidifying air in high humid condition. Additionally, results also indicate a trade-off between the humidity ratio drop with the water vapor removal rate when varying air flowrate.

  15. Study of the effect of water vapor on a resistive plate chamber with glass electrodes

    CERN Document Server

    Sakai, H H; Teramoto, Y; Nakano, E E; Takahashi, T T

    2002-01-01

    We studied the effects of water vapor on the efficiencies of resistive plate chambers with glass electrodes, operated in the streamer mode. With moisture in the chamber gas that has freon as a component (water vapor approx 1000 ppm), a decrease in the efficiency (approx 20%) has been observed after operating for a period of several weeks to a few months. From our study, the cause of the efficiency decrease was identified as a change on the cathode surface. In addition, a recovery method was found: flushing for 1 day with argon bubbled through water containing >=3% ammonia, followed by a few weeks of training with dry gas.

  16. RAMAN LIDAR PROFILING OF WATER VAPOR AND AEROSOLS OVER THE ARM SGP SITE.

    Energy Technology Data Exchange (ETDEWEB)

    FERRARE,R.A.

    2000-01-09

    We have developed and implemented automated algorithms to retrieve profiles of water vapor mixing ratio, aerosol backscattering, and aerosol extinction from Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Raman Lidar data acquired during both daytime and nighttime operations. This Raman lidar system is unique in that it is turnkey, automated system designed for unattended, around-the-clock profiling of water vapor and aerosols (Goldsmith et al., 1998). These Raman lidar profiles are important for determining the clear-sky radiative flux, as well as for validating the retrieval algorithms associated with satellite sensors. Accurate, high spatial and temporal resolution profiles of water vapor are also required for assimilation into mesoscale models to improve weather forecasts. We have also developed and implemented routines to simultaneously retrieve profiles of relative humidity. These routines utilize the water vapor mixing ratio profiles derived from the Raman lidar measurements together with temperature profiles derived from a physical retrieval algorithm that uses data from a collocated Atmospheric Emitted Radiance Interferometer (AERI) and the Geostationary Operational Environmental Satellite (GOES) (Feltz et al., 1998; Turner et al., 1999). These aerosol and water vapor profiles (Raman lidar) and temperature profiles (AERI+GOES) have been combined into a single product that takes advantage of both active and passive remote sensors to characterize the clear sky atmospheric state above the CART site.

  17. Raman lidar profiling of water vapor and aerosols over the ARM SGP Site

    Energy Technology Data Exchange (ETDEWEB)

    Ferrare, R.A.

    2000-01-09

    The authors have developed and implemented automated algorithms to retrieve profiles of water vapor mixing ratio, aerosol backscattering, and aerosol extinction from Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Raman Lidar data acquired during both daytime and nighttime operations. The Raman lidar sytem is unique in that it is turnkey, automated system designed for unattended, around-the-clock profiling of water vapor and aerosols. These Raman lidar profiles are important for determining the clear-sky radiative flux, as well as for validating the retrieval algorithms associated with satellite sensors. Accurate, high spatial and temporal resolution profiles of water vapor are also required for assimilation into mesoscale models to improve weather forecasts. The authors have also developed and implemented routines to simultaneously retrieve profiles of relative humidity. These routines utilize the water vapor mixing ratio profiles derived from the Raman lidar measurements together with temperature profiles derived from a physical retrieval algorithm that uses data from a collocated Atmospheric Emitted Radiance Interferometer (AERI) and the Geostationary Operational Environmental Satellite (GOES). These aerosol and water vapor profiles (Raman lidar) and temperature profiles (AERI+GOES) have been combined into a single product that takes advantage of both active and passive remote sensors to characterize the clear sky atmospheric state above the CART site.

  18. Three dimensional ray tracing technique for tropospheric water vapor tomography using GPS measurements

    Science.gov (United States)

    Haji Aghajany, Saeid; Amerian, Yazdan

    2017-11-01

    Tropospheric water vapor has a key role in tropospheric processes and it is an important parameter in meteorology studies. Because of its non-uniform spatiotemporal distribution, modeling the spatiotemporal variations of water vapor is a challenging subject in meteorology. The GNSS tomography of the troposphere is a promising method to assess the spatiotemporal distribution of water vapor parameter in this layer. The tomography method efficiency is dependent on the ray tracing technique and GPS derived tropospheric slant wet delays. Implementing constraints and regularization methods are necessary in order to achieve the regularized solution in troposphere tomography. In this paper, the three dimensional (3D) ray tracing technique based on Eikonal equations and ERA-I data are used to perform the reconstruction the signal path, Iranian Permanent GPS Network (IPGN) measurements are used to calculate slant wet delays and the LSQR regularization technique is used to obtain a regularized tomographic solution for tropospheric water vapor. The modeled water vapor profiles are validated using radiosonde observations.

  19. Herschel observations of cold water vapor and ammonia in protoplanetary disks

    Science.gov (United States)

    Hogerheijde, Michiel R.; Bergin, Edwin A.; Brinch, Christian; Cleeves, L. Ilsedore; Fogel, Jeffrey K. J.; Blake, Geoffrey A.; Dominik, Carsten; Lis, Dariusz C.; Melnick, Gary; Neufeld, David; Panić, Olja; Pearson, John C.; Kristensen, Lars; Yíldíz, Umut A.; van Dishoeck, Ewine F.

    2012-03-01

    We present the results of a Herschel/HIFI study into the presence of cold water vapor in a sample of protoplanetary disks, carried out as part of the Guaranteed Time Key Program `Water in Star Forming Regions with Herschel' (WISH). While toward most disks only upper limits are obtained, rotational ground-state emission lines of ortho-H_2O and para-H_2O are clearly detected toward the disk of TW Hya. The detection of cold water vapor, extending to at least 115 AU, in this disk indicates the presence of a vast reservoir of water ice totalling ˜ 1028 g or thousands of Earth Oceans. Photodesorption by stellar ultraviolet radiation likely liberates a small amount of water vapor from icy grains. Significant settling of such icy grains toward the disk midplane is required to match the detected amount of water vapor. The water ortho-to-para ratio of 0.77 is significantly different from that observed in Solar System comets where a range of 1.5--3 is found. If this reflects the temperature regime of the water ice (formation), this finding suggests that long-range mixing of volatiles has occured in the Solar Nebula. The same Herschel/HIFI data also detect the emission of NH_3 in TW Hya's disk, and the implications of this finding are discussed.

  20. Dissolution kinetics of volatile organic compound vapors in water : An integrated experimental and computational study

    NARCIS (Netherlands)

    G. Mahmoodlu, Mojtaba; Pontedeiro, Elizabeth M.; Pérez Guerrero, Jesús S.; Raoof, Amir; Hassanizadeh, S. Majid; van Genuchten, Martinus Th

    In this study we performed batch experiments to investigate the dissolution kinetics of trichloroethylene (TCE) and toluene vapors in water at room temperature and atmospheric pressure. The batch systems consisted of a water reservoir and a connected headspace, the latter containing a small glass

  1. Validation of the Harvard Lyman-α in situ water vapor instrument: Implications for the mechanisms that control stratospheric water vapor

    Science.gov (United States)

    Weinstock, E. M.; Smith, J. B.; Sayres, D. S.; Pittman, J. V.; Spackman, J. R.; Hintsa, E. J.; Hanisco, T. F.; Moyer, E. J.; St. Clair, J. M.; Sargent, M. R.; Anderson, J. G.

    2009-12-01

    Building on previously published details of the laboratory calibrations of the Harvard Lyman-α photofragment fluorescence hygrometer (HWV) on the NASA ER-2 and WB-57 aircraft, we describe here the validation process for HWV, which includes laboratory calibrations and intercomparisons with other Harvard water vapor instruments at water vapor mixing ratios from 0 to 10 ppmv, followed by in-flight intercomparisons with the same Harvard hygrometers. The observed agreement exhibited in the laboratory and during intercomparisons helps corroborate the accuracy of HWV. In light of the validated accuracy of HWV, we present and evaluate a series of intercomparisons with satellite and balloon borne water vapor instruments made from the upper troposphere to the lower stratosphere in the tropics and midlatitudes. Whether on the NASA ER-2 or WB-57 aircraft, HWV has consistently measured about 1-1.5 ppmv higher than the balloon-borne NOAA/ESRL/GMD frost point hygrometer (CMDL), the NOAA Cryogenic Frost point Hygrometer (CFH), and the Microwave Limb Sounder (MLS) on the Aura satellite in regions of the atmosphere where water vapor is <10 ppmv. Comparisons in the tropics with the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite show large variable differences near the tropopause that converge to ˜10% above 460 K, with HWV higher. Results we show from the Aqua Validation and Intercomparison Experiment (AquaVIT) at the AIDA chamber in Karlsruhe do not reflect the observed in-flight differences. We illustrate that the interpretation of the results of comparisons between modeled and measured representations of the seasonal cycle of water entering the lower tropical stratosphere is dictated by which data set is used.

  2. Preconditioning of the YSZ-NiO Fuel Cell Anode in Hydrogenous Atmospheres Containing Water Vapor.

    Science.gov (United States)

    Vasyliv, Bogdan; Podhurska, Viktoriya; Ostash, Orest

    2017-12-01

    The YSZ-NiO ceramics for solid oxide fuel cells (SOFCs) anode have been investigated. A series of specimens were singly reduced in a hydrogenous atmosphere (Ar-5 vol% H2 mixture) at 600 °C under the pressure of 0.15 MPa or subjected to 'reduction in the mixture-oxidation in air' (redox) cycling at 600 °C. The YSZ-Ni cermets formed in both treatment conditions were then aged in 'water vapor in Ar-5 vol% H2 mixture' atmosphere at 600 °C under the pressure of 0.15 MPa. Additionally, the behaviour of the as-received material in this atmosphere was studied. It was revealed that small amount of water vapor in Ar-5 vol% H2 mixture (water vapor pressure below 0.03 MPa) does not affect the reduction of the nickel phase in the YSZ-NiO ceramics, but causes some changes in the YSZ-Ni cermet structure. In particular, nanopore growth in tiny Ni particles takes place. At higher concentration of water vapor in the mixture (water vapor pressure above 0.03-0.05 MPa), converse changes in the kinetics of reduction occur. The best physical and mechanical properties were revealed for the material treated by redox cycling after holding at 600 °C in water depleted gas mixture. The dual effect of water vapor on nickel-zirconia anode behaviour is discussed basing on scanning electron microscopy analysis data, material electrical conductivity, and strength.

  3. Pebax®1657/Graphene oxide composite membranes for improved water vapor separation

    KAUST Repository

    Akhtar, Faheem Hassan

    2016-11-02

    In this study composite mixed matrix membranes containing hydrophilic microphase-separated block copolymer (Pebax® 1657) and graphene oxide nanosheets were prepared using a dip coating method. Water vapor and N2 gas permeation were measured as a function of different parameters: (i) layer thickness, (ii) content of graphene oxide (GO), and (iii) content of reduced GO. Surprisingly, a concentration of only 2 wt% of GO nanosheets well dispersed in the Pebax layer boosted the selectivity 8 times by decreasing the water vapor permeance by only 12% whereas N2 gas permeance decreased by 70%. Using reduced GO instead, the water vapor permeance declined by up to 16% with no influence on the N2 gas permeance. We correlated the permeation properties of the mixed matrix membranes with different models and found, that both the modified Nielsen model and the Cussler model give good correlation with experimental findings.

  4. Alexandrite lidar for the atmospheric water vapor detection and development of powerful tunable sources in IR

    Science.gov (United States)

    Uchiumi, M.; Maeda, M.; Muraoka, K.; Uchino, O.

    1992-01-01

    New tunable solid-state lasers, such as alexandrite and Ti-sapphire lasers, provide a powerful technique to detect various molecules in the atmosphere whose absorption bands are in the infrared region. The differential absorption lidar (DIAL) system to measure the tropospheric water vapor has been investigated by many authors, in an early stage, by dye and ruby lasers. Using the alpha band of water vapor, the longest detection range can be obtained with high accuracy, and the alexandrite laser is the most suitable laser for this purpose. In this paper, we describe the detection of water vapor in the atmosphere by an alexandrite lidar, and the development of powerful tunable sources based on Raman lasers in the infrared region.

  5. Mesospheric water vapor. Variability at different timescales observed by ground-based microwave spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hallgren, Kristofer

    2011-07-01

    The importance of water vapor in Earth's atmosphere cannot be understated. It is an active green-house gas, important energy conveyer in the troposhere and a key element in many chemical reactions in the middle atmosphere. Yet, there are still many questions concerning the water vapor dynamics in the middle atmosphere. This thesis present a new, state-of-the art, microwave instrument developed in order to shed light on some of these issues. The high sensitivity and time-resolution enable us to resolve fast dynamical events which was not possible before. Furthermore it expands an already long dataset and a mean vertical distribution of water vapor for polar latitudes is presented. (orig.)

  6. Observational Constraints on the Water Vapor Feedback Using GPS Radio Occultations

    Science.gov (United States)

    Vergados, P.; Mannucci, A. J.; Ao, C. O.; Fetzer, E. J.

    2016-12-01

    The air refractive index at L-band frequencies depends on the air's density and water vapor content. Exploiting these relationships, we derive a theoretical model to infer the specific humidity response to surface temperature variations, dq/dTs, given knowledge of how the air refractive index and temperature vary with surface temperature. We validate this model using 1.2-1.6 GHz Global Positioning System Radio Occultation (GPS RO) observations from 2007 to 2010 at 250 hPa, where the water vapor feedback on surface warming is strongest. Current research indicates that GPS RO data sets can capture the amount of water vapor in very dry and very moist air more efficiently than other observing platforms, possibly suggesting larger water vapor feedback than previously known. Inter-comparing the dq/dTs among different data sets will provide us with additional constraints on the water vapor feedback. The dq/dTs estimation from GPS RO observations shows excellent agreement with previously published results and the responses estimated using Atmospheric Infrared Sounder (AIRS) and NASA's Modern-Era Retrospective Analysis for Research and Applications (MERRA) data sets. In particular, the GPS RO-derived dq/dTs is larger by 6% than that estimated using the AIRS data set. This agrees with past evidence that AIRS may be dry-biased in the upper troposphere. Compared to the MERRA estimations, the GPS RO-derived dq/dTs is 10% smaller, also agreeing with previous results that show that MERRA may have a wet bias in the upper troposphere. Because of their high sensitivity to fractional changes in water vapor, and their inherent long-term accuracy, current and future GPS RO observations show great promise in monitoring climate feedbacks and their trends.

  7. Temporal Variations of Telluric Water Vapor Absorption at Apache Point Observatory

    Science.gov (United States)

    Li, Dan; Blake, Cullen H.; Nidever, David; Halverson, Samuel P.

    2018-01-01

    Time-variable absorption by water vapor in Earth’s atmosphere presents an important source of systematic error for a wide range of ground-based astronomical measurements, particularly at near-infrared wavelengths. We present results from the first study on the temporal and spatial variability of water vapor absorption at Apache Point Observatory (APO). We analyze ∼400,000 high-resolution, near-infrared (H-band) spectra of hot stars collected as calibration data for the APO Galactic Evolution Experiment (APOGEE) survey. We fit for the optical depths of telluric water vapor absorption features in APOGEE spectra and convert these optical depths to Precipitable Water Vapor (PWV) using contemporaneous data from a GPS-based PWV monitoring station at APO. Based on simultaneous measurements obtained over a 3° field of view, we estimate that our PWV measurement precision is ±0.11 mm. We explore the statistics of PWV variations over a range of timescales from less than an hour to days. We find that the amplitude of PWV variations within an hour is less than 1 mm for most (96.5%) APOGEE field visits. By considering APOGEE observations that are close in time but separated by large distances on the sky, we find that PWV is homogeneous across the sky at a given epoch, with 90% of measurements taken up to 70° apart within 1.5 hr having ΔPWV < 1.0 mm. Our results can be used to help simulate the impact of water vapor absorption on upcoming surveys at continental observing sites like APO, and also to help plan for simultaneous water vapor metrology that may be carried out in support of upcoming photometric and spectroscopic surveys.

  8. Adsorption of N-hexane, methanol and water vapor and binary mixtures of N-hexane/water vapor on super activated carbon nanoparticles

    Science.gov (United States)

    Prado, Jesus Antonio

    Recent times have seen a large rise in the utilization of engineered nanomaterials (ENMs) within a wide variety of industries due to their unique properties. Consequently, the fabrication, application and disposal of ENMs will inevitably lead to their release to the environment. Once ENMs are in the environment, they may undergo atmospheric transformations, such the sorption of hazardous air pollutants (HAPs) or water vapor. These transformed ENMs may then affect the general public through inhalation -- or other pathways of exposure -- and those employed by the ever-growing nanotechnology sector are of particular vulnerability. As a result, it is important to evaluate the adsorption characteristics of a common carbon-based ENM under the presence of HAPs or water vapor which may adsorb onto them. This study investigated the unary and binary gas-phase adsorption of n-hexane, methanol and water vapor on super activated carbon nanoparticles (SACNPs) with a bench-scale adsorption system. Removal efficiencies, breakthrough tests, throughput ratios, adsorption capacities and kinetics modeling were completed to assess the adsorption behavior of the SACNPs.

  9. Membrane-assisted vapor stripping: energy efficient hybrid distillation-vapor permeation process for alcohol-water separation

    Science.gov (United States)

    BACKGROUND: Energy efficient alternatives to distillation for alcohol recovery from dilute solution are needed to improve biofuel sustainability. A process integrating steam stripping with a vapor compression step and a vapor permeation membrane separation step is proposed. The...

  10. Water Repellence and Oxygen and Water Vapor Barrier of PVOH-Coated Substrates before and after Surface Esterification

    Directory of Open Access Journals (Sweden)

    Markus Schmid

    2014-11-01

    Full Text Available This study investigates chemical grafting with fatty acid chlorides as a method for the surface modification of hydrophilic web materials. The resulting changes in the water repellence and barrier properties were studied. For this purpose, different grades of polyvinyl alcohol (PVOH were coated on regenerated cellulose films (“cellophane” and paper and then grafted with fatty acid chlorides. The PVOH grades varied in their degree of hydrolysis and average molecular weight. The surface was esterified with two fatty acid chlorides, palmitoyl (C16 and stearoyl chloride (C18, by chemical grafting. The chemical grafting resulted in water-repellent surfaces and reduced water vapor transmission rates by a factor of almost 19. The impact of the surface modification was greater for a higher degree of hydrolysis of the polyvinyl alcohol and for shorter fatty acid chains. Although the water vapor barrier for palmitoyl-grafted PVOH was higher than for stearoyl-grafted PVOH, the contact angle with water was lower. Additionally, it was shown that a higher degree of hydrolysis led to higher water vapor barrier improvement factors after grafting. Furthermore, the oxygen permeability decreased after grafting significantly, due to the fact that the grafting protects the PVOH against humidity when the humidity is applied on the grafted side. It can be concluded that the carbon chain length of the fatty acid chlorides is the limiting factor for water vapor adsorption, but the grafting density is the bottleneck for water diffusing in the polymer.

  11. Water vapor and gas transport through PEO PBT block copolymers

    NARCIS (Netherlands)

    Metz, S.J.; Potreck, Jens; Mulder, M.H.V.; Wessling, Matthias

    2002-01-01

    Introduction At the bore well natural gas is saturated with water. Downstream the presence of water may cause: formation of methane hydrates (blocking eventually the pipeline), condensation of water in the pipeline and corrosion effects. A process used for the dehydration of natural gas is glycol

  12. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    Energy Technology Data Exchange (ETDEWEB)

    Periolatto, M.; Spena, P. Russo [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano (Italy); Sangermano, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino (Italy)

    2016-05-18

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  13. Water Vapor Desorption Characteristics of Honeycomb Type Sorption Element Composed of Organic Sorbent

    Science.gov (United States)

    Inaba, Hideo; Kida, Takahisa; Horibe, Akihiko; Kaneda, Makoto; Okamoto, Tamio; Seo, Jeong-Kyun

    This paper describes the water vapor desorption characteristics of honeycomb shape type sorbent element containing new organic sorbent of the bridged complex of sodium polyacrylate. The transient experiments in which the dry air was passed into the honeycomb type sorbent element sorbed water vapor were carried out under various conditions of air velocity, temperature, relative humidity and honeycomb length. The obtained data for desorption process were compared with those for sorption process. Finally, Sherwood number of mass transfer of the organic sorbent for desorption process was derived in terms of Reynolds number, modified Stefan number and non-dimensional honeycomb length.

  14. Simulation of stratospheric water vapor trends: impact on stratospheric ozone chemistry

    Directory of Open Access Journals (Sweden)

    A. Stenke

    2005-01-01

    Full Text Available A transient model simulation of the 40-year time period 1960 to 1999 with the coupled climate-chemistry model (CCM ECHAM4.L39(DLR/CHEM shows a stratospheric water vapor increase over the last two decades of 0.7 ppmv and, additionally, a short-term increase after major volcanic eruptions. Furthermore, a long-term decrease in global total ozone as well as a short-term ozone decline in the tropics after volcanic eruptions are modeled. In order to understand the resulting effects of the water vapor changes on lower stratospheric ozone chemistry, different perturbation simulations were performed with the CCM ECHAM4.L39(DLR/CHEM feeding the water vapor perturbations only to the chemistry part. Two different long-term perturbations of lower stratospheric water vapor, +1 ppmv and +5 ppmv, and a short-term perturbation of +2 ppmv with an e-folding time of two months were applied. An additional stratospheric water vapor amount of 1 ppmv results in a 5–10% OH increase in the tropical lower stratosphere between 100 and 30 hPa. As a direct consequence of the OH increase the ozone destruction by the HOx cycle becomes 6.4% more effective. Coupling processes between the HOx-family and the NOx/ClOx-family also affect the ozone destruction by other catalytic reaction cycles. The NOx cycle becomes 1.6% less effective, whereas the effectiveness of the ClOx cycle is again slightly enhanced. A long-term water vapor increase does not only affect gas-phase chemistry, but also heterogeneous ozone chemistry in polar regions. The model results indicate an enhanced heterogeneous ozone depletion during antarctic spring due to a longer PSC existence period. In contrast, PSC formation in the northern hemisphere polar vortex and therefore heterogeneous ozone depletion during arctic spring are not affected by the water vapor increase, because of the less PSC activity. Finally, this study shows that 10% of the global total ozone decline in the transient model run

  15. Measurements of the vertical profile of water vapor abundance in the Martian atmosphere from Mars Observer

    Science.gov (United States)

    Schofield, J. T.; Mccleese, Daniel J.

    1988-01-01

    An analysis is presented of the Pressure Modulator Infrared Radiometer (PMIRR) capabilities along with how the vertical profiles of water vapor will be obtained. The PMIRR will employ filter and pressure modulation radiometry using nine spectral channels, in both limb scanning and nadir sounding modes, to obtain daily, global maps of temperature, dust extinction, condensate extinction, and water vapor mixing ratio profiles as a function of pressure to half scale height or 5 km vertical resolution. Surface thermal properties will also be mapped, and the polar radiactive balance will be monitored.

  16. Analysis on Characteristics of Radiosonde Bias Using GPS Precipitable Water Vapor

    Directory of Open Access Journals (Sweden)

    Chang-Geun Park

    2010-09-01

    Full Text Available As an observation instrument of the longest record of tropospheric water vapor, radiosonde data provide upper-air pressure (geopotential height, temperature, humidity and wind. However, the data have some well-known elements related to inaccuracy. In this article, radiosonde precipitable water vapor (PWV at Sokcho observatory was compared with global positioning system (GPS PWV during each summertime of year 2007 and 2008 and the biases were calculated. As a result, the mean bias showed negative values regardless of the rainfall occurrence. In addition, on the basis of GPS PWV, the maximum root mean square error (RMSE was 5.67 mm over the radiosonde PWV.

  17. The influence of water vapor on atmospheric exchange measurements with an ICOS* based Laser absorption analyzer

    Science.gov (United States)

    Bunk, Rüdiger; Quan, Zhi; Wandel, Matthias; Yi, Zhigang; Bozem, Heiko; Kesselmeier, Jürgen

    2014-05-01

    Carbonyl sulfide and carbon monoxide are both atmospheric trace gases of high interest. Recent advances in the field of spectroscopy have enabled instruments that measure the concentration of the above and other trace gases very fast and with good precision. Increasing the effective path length by reflecting the light between two mirrors in a cavity, these instruments reach impressive sensitivities. Often it is possible to measure the concentration of more than one trace gas at the same time. The OCS/CO2 Analyzer by LGR (Los Gatos Research, Inc.) measures the concentration of water vapor [H2O], carbonyl sulfide [COS], carbon dioxide [CO2] and carbon monoxide [CO] simultaneously. For that the cavity is saturated with light, than the attenuation of light is measured as in standard absorption spectroscopy. The instrument proved to be very fast with good precision and to be able to detect even very low concentrations, especially for COS (as low as 30ppt in the case of COS). However, we observed a rather strong cross sensitivity to water vapor. Altering the water vapor content of the sampled air with two different methods led to a change in the perceived concentration of COS, CO and CO2. This proved especially problematic for enclosure (cuvette) measurements, where the concentrations of one of the above species in an empty cuvette are compared to the concentration of another cuvette containing a plant whose exchange of trace gases with the atmosphere is of interest. There, the plants transpiration leads to a large difference in water vapor content between the cuvettes and that in turn produces artifacts in the concentration differences between the cuvettes for the other above mentioned trace gases. For CO, simultaneous measurement with a UV-Emission Analyzer (AL 5002, Aerolaser) and the COS/CO Analyzer showed good agreement of perceived concentrations as long as the sample gas was dry and an increasing difference in perceived concentration when the sample gas was

  18. Compact Raman Lidar Measurement of Liquid and Vapor Phase Water Under the Influence of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Shiina Tatsuo

    2016-01-01

    Full Text Available A compact Raman lidar has been developed for studying phase changes of water in the atmosphere under the influence of ionization radiation. The Raman lidar is operated at the wavelength of 349 nm and backscattered Raman signals of liquid and vapor phase water are detected at 396 and 400 nm, respectively. Alpha particles emitted from 241Am of 9 MBq ionize air molecules in a scattering chamber, and the resulting ions lead to the formation of liquid water droplets. From the analysis of Raman signal intensities, it has been found that the increase in the liquid water Raman channel is approximately 3 times as much as the decrease in the vapor phase water Raman channel, which is consistent with the theoretical prediction based on the Raman cross-sections. In addition, the radius of the water droplet is estimated to be 0.2 μm.

  19. Q Conversion Factor Models for Estimating Precipitable Water Vapor for Turkey

    Science.gov (United States)

    Deniz, Ilke; Mekik, Cetin; Gurbuz, Gokhan

    2015-04-01

    Global Navigation Satellite Systems (GNSS) have recently proved to be one of the crucial tools for determining continuous and precise precipitable water vapor (GNSS-MET networks). GNSS, especially CORS networks such as CORS-TR (the Turkish Network-RTK), provide high temporal and spatial accuracy for the wet tropospheric zenith delays which are then converted to the precipitable water vapor due to the fact that they can operate in all weather conditions continuously and economically. The accuracy of wet tropospheric zenith delay highly depends on the accuracy of precipitable water vapor content in the troposphere. Therefore, the precipitable water vapor is an important element of the tropospheric zenith delay. A number of studies can be found in the literature on the determination of the precipitable water vapor from the tropospheric zenith delay. Studies of Hogg showed that when the precipitable water vapor is known, the tropospheric zenith delay can be computed. Askne and Nodius have developed fundamental equations between the wet tropospheric zenith delay and the precipitable water vapor from the equation of the index of refraction in the troposphere. Furthermore, Bevis have developed a linear regression model to determine the weighted mean temperature (Tm) depending on the surface temperature (Ts) in Askne and Nodius studies. For this reason, nearly 9000 radiosonde profiles in USA were analyzed and the coefficients calculated. Similarly, there are other studies on the calculation of those coefficients for different regions: Solbrig for Germany, Liou for Taiwan, Jihyun for South Korea, Dongseob for North Korea, Suresh Raju for India, Boutiouta and Lahcene for Algeria, Bokoye for Canada, Baltink for Netherlands and Baltic, Bock for Africa. It is stated that the weighted mean temperature can be found with a root mean square error of ±2-5 K. In addition, there are studies on the calculation of the coefficients globally. Another model for the determination of

  20. Modeling of a water vapor selective membrane unit to increase the energy efficiency of humidity harvesting

    Science.gov (United States)

    Bergmair, D.; Metz, S. J.; de Lange, H. C.; van Steenhoven, A. A.

    2012-11-01

    Air humidity is a promising source of clean and safe drinking water. However, in conventional systems a lot of energy is wasted on the production of cold air, rather than the condensation of water vapor. This study examines the possibility of using a hollow fiber membrane module to make this process more energy efficient, by separating the vapor from other gases, prior to the cooling process with the help of selective membranes. The water vapor concentration within a fiber has been modeled using a random walker approach, and the membrane permeability has been implemented as a re-bounce probability for simulation particles interacting with the membrane. Considering the additional work requirement for driving a feed flow through the membrane section and the computed water vapor permeation it could be shown that the energy demand per unit water is lowest for slow flow speeds and favors short and thin fibers. The total energy requirement was estimated to be less than half of the conventional one. Comparison with other CFD simulations and a real life module has shown a good level of agreement, indicating that a membrane section could improve the energy efficiency of humidity harvesting significantly.

  1. Deuterium excess in subtropical free troposphere water vapor: Continuous measurements from the Chajnantor Plateau, northern Chile

    Science.gov (United States)

    Samuels-Crow, Kimberly E.; Galewsky, Joseph; Sharp, Zachary D.; Dennis, Kate J.

    2014-12-01

    Water vapor measured continuously by cavity ring-down spectroscopy from July 2012 to March 2013 on the hyperarid Chajnantor Plateau, northern Chile (elevation = 5080 m, pressure ≈ 550 hPa), has a mean deuterium excess (d-excess = δD - 8*δ18O) of 46‰ ± 5‰ and frequently exceeds 100‰ at low water vapor mixing ratios (q ≤ 500 ppmv). These measurements provide empirical support for theoretical predictions of free troposphere d-excess. The d-excess measured at this site can be understood in terms of supersaturation with respect to ice at relative humidities between 100% and 130%, followed by mixing with moist midtropospheric or lower tropospheric air en route to the plateau. The d-excess measured at Chajnantor is consistent with predictions for d-excess in the upper troposphere from isotope-enabled general circulation models and with high vapor saturation over ice in cloud-resolving and microphysical models.

  2. Eggshell permeability: a standard technique for determining interspecific rates of water vapor conductance.

    Science.gov (United States)

    Portugal, Steven J; Maurer, Golo; Cassey, Phillip

    2010-01-01

    Typically, eggshell water vapor conductance is measured on whole eggs, freshly collected at the commencement of a study. At times, however, it may not be possible to obtain whole fresh eggs but rather egg fragments or previously blown eggs. Here we evaluate and describe in detail a technique for modern laboratory analysis of eggshell conductance that uses fragments from fresh and museum eggs to determine eggshell water vapor conductance. We used fresh unincubated eggs of domesticated chickens (Gallus gallus domesticus), ducks (Anas platyrhynchos domesticus), and guinea fowl (Numida meleagris) to investigate the reliability, validity, and repeatability of the technique. To assess the suitability of museum samples, museum and freshly collected black-headed gull eggs (Larus ridibundus) were used. Fragments were cut out of the eggshell from the blunt end (B), equator (E), and pointy end (P). Eggshell fragments were glued to the top of a 0.25-mL micro test tube (Eppendorf) filled with 200 μL of distilled water and placed in a desiccator at 25°C. Eppendorfs were weighed three times at 24-h intervals, and mass loss was assumed to be a result of water evaporation. We report the following results: (1) mass loss between weighing sessions was highly repeatable and consistent in all species; (2) the majority of intraspecific variability in eggshell water vapor conductance between different eggs of the same species was explained through the differences in water vapor conductance between the three eggshell parts of the same egg (B, E, and P); (3) the technique was sensitive enough to detect significant differences between the three domestic species; (4) there was no overall significant difference between water vapor conductance of museum and fresh black-headed gull eggs; (5) there was no significant difference in water vapor conductance for egg fragments taken from the same egg both between different trials and within the same trial. We conclude, therefore, that this technique

  3. Eddy Covariance measurements of stable isotopes (δD and δ18O) in water vapor

    Science.gov (United States)

    Braden-Behrens, Jelka; Knohl, Alexander

    2017-04-01

    Stable isotopes are a promising tool to enhance our understanding of ecosystem gas exchanges. Studying 18O and 2H in water vapour (H2Ov) can e.g. help partitioning evapotranspiration into its components. With recent developments in laser spectroscopy direct Eddy Covariance (EC) measurements for investigating fluxes of stable isotopologues became feasible. So far very few case studies have applied the EC method to measure stable isotopes in water vapor. We continuously measure fluxes of water vapor isotopologues with the EC method in a managed beech forest in Thuringia, Germany, since autumn 2015 using the following setup: An off-axis integrated cavity output water vapor isotope analyzer (WVIA, Los Gatos Research. Inc, USA) measures the water vapour concentration and its isotopic composition (δD and δ18O). The instrument, that was optimized for high flow rates (app. 4slpm) to generate high frequency (2Hz) measurements, showed sufficient precision with Allan Deviations of app. 0.12 ‰ for δD and 0.06 ‰ for δ18O for averaging periods of 100s. The instrument was calibrated hourly using a high-flow optimized version of the water vapor isotope standard source (WVISS, Los Gatos Research. Inc, USA) that provides water vapor with known isotopic composition for a large range of different concentrations. Our calibration scheme includes a near continuous concentration range calibration instead of a simple 2 or 3-point calibration to face the analyzers strong concentration dependency within a range of app. 6 000 to 16 000 ppm in winter and app. 8 000 to 23 000 ppm in summer. In the used setup, the high-flow and high-frequency optimized water vapor isotope analyzer (WVIA) showed suitable characteristics (Allan deviation and spectral energy distribution) to perform Eddy covariance measurements of stable isotopes in H2Ov. Thus, this novel instrument for EC measurements of water vapor isotopologues provides a new opportunity for studying the hydrological cycle in long

  4. FIRST DETECTION OF WATER VAPOR IN A PRE-STELLAR CORE

    Energy Technology Data Exchange (ETDEWEB)

    Caselli, Paola; Douglas, Thomas [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Keto, Eric [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bergin, Edwin A. [Department of Astronomy, The University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Tafalla, Mario [Observatorio Astronomico Nacional (IGN), Calle Alfonso XII, 3, E-28014 Madrid (Spain); Aikawa, Yuri [Department of Earth and Planetary Sciences, Kobe University, Nada, 657-8501 Kobe (Japan); Pagani, Laurent [LERMA and UMR 8112 du CNRS, Observatoire de Paris, 61 Av. de l' Observatoire, F-75014 Paris (France); Yildiz, Umut A.; Kristensen, Lars E.; Van Dishoeck, Ewine F. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Van der Tak, Floris F. S. [SRON Netherlands Institute for Space Research, P.O. Box 800, 9700 AV, Groningen (Netherlands); Walmsley, C. Malcolm; Codella, Claudio [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Nisini, Brunella, E-mail: p.caselli@leeds.ac.uk [INAF-Osservatorio Astronomico di Roma, I-00040 Monte Porzio Catone (Italy)

    2012-11-10

    Water is a crucial molecule in molecular astrophysics as it controls much of the gas/grain chemistry, including the formation and evolution of more complex organic molecules in ices. Pre-stellar cores provide the original reservoir of material from which future planetary systems are built, but few observational constraints exist on the formation of water and its partitioning between gas and ice in the densest cores. Thanks to the high sensitivity of the Herschel Space Observatory, we report on the first detection of water vapor at high spectral resolution toward a dense cloud on the verge of star formation, the pre-stellar core L1544. The line shows an inverse P-Cygni profile, characteristic of gravitational contraction. To reproduce the observations, water vapor has to be present in the cold and dense central few thousand AU of L1544, where species heavier than helium are expected to freeze out onto dust grains, and the ortho:para H{sub 2} ratio has to be around 1:1 or larger. The observed amount of water vapor within the core (about 1.5 Multiplication-Sign 10{sup -6} M{sub Sun }) can be maintained by far-UV photons locally produced by the impact of galactic cosmic rays with H{sub 2} molecules. Such FUV photons irradiate the icy mantles, liberating water vapor in the core center. Our Herschel data, combined with radiative transfer and chemical/dynamical models, shed light on the interplay between gas and solids in dense interstellar clouds and provide the first measurement of the water vapor abundance profile across the parent cloud of a future solar-type star and its potential planetary system.

  5. First Detection of Water Vapor in a Pre-stellar Core

    Science.gov (United States)

    Caselli, Paola; Keto, Eric; Bergin, Edwin A.; Tafalla, Mario; Aikawa, Yuri; Douglas, Thomas; Pagani, Laurent; Yíldíz, Umut A.; van der Tak, Floris F. S.; Walmsley, C. Malcolm; Codella, Claudio; Nisini, Brunella; Kristensen, Lars E.; van Dishoeck, Ewine F.

    2012-11-01

    Water is a crucial molecule in molecular astrophysics as it controls much of the gas/grain chemistry, including the formation and evolution of more complex organic molecules in ices. Pre-stellar cores provide the original reservoir of material from which future planetary systems are built, but few observational constraints exist on the formation of water and its partitioning between gas and ice in the densest cores. Thanks to the high sensitivity of the Herschel Space Observatory, we report on the first detection of water vapor at high spectral resolution toward a dense cloud on the verge of star formation, the pre-stellar core L1544. The line shows an inverse P-Cygni profile, characteristic of gravitational contraction. To reproduce the observations, water vapor has to be present in the cold and dense central few thousand AU of L1544, where species heavier than helium are expected to freeze out onto dust grains, and the ortho:para H2 ratio has to be around 1:1 or larger. The observed amount of water vapor within the core (about 1.5 × 10-6 M ⊙) can be maintained by far-UV photons locally produced by the impact of galactic cosmic rays with H2 molecules. Such FUV photons irradiate the icy mantles, liberating water vapor in the core center. Our Herschel data, combined with radiative transfer and chemical/dynamical models, shed light on the interplay between gas and solids in dense interstellar clouds and provide the first measurement of the water vapor abundance profile across the parent cloud of a future solar-type star and its potential planetary system.

  6. Mapping Mars water vapor with the Very Large Array

    Science.gov (United States)

    Clancy, R. T.; Grossman, Arie W.; Muhleman, Duane O.

    1992-01-01

    This paper presents the first radio measurements of Mars atmospheric water, retrieved from interferometric spectral line observations with the NRAO VLA. Large atmospheric path lengths on the limb of Mars lead to an annulus of H2O line emission which provides a measure of the diurnal and latitudinal variability of atmospheric water on Mars. The measured line shapes of the observed H2O emission yield the first direct measurements of the vertical mixing profile of H2O in the Mars atmosphere. The observations indicate a very dry Mars atmosphere in which the globally averaged water column is approximately 3 pr micron.

  7. Using JPSS Retrievals to Implement a Multisensor, Synoptic, Layered Water Vapor Product for Forecasters

    Science.gov (United States)

    Forsythe, J. M.; Jones, A. S.; Kidder, S. Q.; Fuell, K.; LeRoy, A.; Bikos, D.; Szoke, E.

    2015-12-01

    Forecasters have been using the NOAA operational blended total precipitable water (TPW) product, developed by the Cooperative Institute for Research in the Atmosphere (CIRA), since 2009. Blended TPW has a wide variety of uses related to heavy precipitation and flooding, such as measuring the amount of moisture in an atmospheric river originating in the tropics. But blended TPW conveys no information on the vertical distribution of moisture, which is relevant to a variety of forecast concerns. Vertical profile information is particularly lacking over the oceans for landfalling storms. A blended six-satellite, four-layer, layered water vapor product demonstrated by CIRA and the NASA Short-term Prediction Research and Transition Center (SPoRT) in allows forecasters to see the vertical distribution of water vapor in near real-time. National Weather Service (NWS) forecaster feedback indicated that this new, vertically-resolved view of water vapor has a substantial impact on forecasts. This product uses NOAA investments in polar orbiting satellite sounding retrievals from passive microwave radiances, in particular, the Microwave Integrated Retrieval System (MIRS). The product currently utilizes data from the NOAA-18 and -19 spacecraft, Metop-A and -B, and the Defense Meteorological Program (DMSP) F18 spacecraft. The sounding instruments onboard the Suomi-NPP and JPSS spacecraft will be cornerstone instruments in the future evolution of this product. Applications of the product to heavy rain cases will be presented and compared to commonly used data such as radiosondes and Geostationary Operational Environmental Satellite (GOES) water vapor channel imagery. Research is currently beginning to implement advective blending, where model winds are used to move the water vapor profiles to a common time. Interactions with the NOAA Satellite Analysis Branch (SAB), National Center for Environmental Prediction (NCEP) centers including the Ocean Prediction Center (OPC) and Weather

  8. Cavity-ring-down spectroscopy on water vapor in the range 555-604 nm

    NARCIS (Netherlands)

    Naus, H.; Ubachs, W.M.G.; Levelt, P.F.; Polyansky, O.L.; Zobov, N.F.; Tennyson, J.

    2001-01-01

    The method of pulsed cavity-ring-down spectroscopy was employed to record the water vapor absorption spectrum in the wavelength range 555-604 nm. The spectrum consists of 1830 lines, calibrated against the iodine standard with an accuracy of 0.01 cm

  9. Transport of water vapor and inert gas mixtures through highly selective and highly permeable polymer membranes

    NARCIS (Netherlands)

    Metz, S.J.; van de Ven, W.J.C.; Potreck, Jens; Mulder, M.H.V.; Wessling, Matthias

    2005-01-01

    This paper studies in detail the measurement of the permeation properties of highly permeable and highly selective polymers for water vapor/nitrogen gas mixtures. The analysis of the mass transport of a highly permeable polymer is complicated by the presence of stagnant boundary layers at feed and

  10. Water vapor selective thin film nanocomposite membranes prepared by functionalized Silicon nanoparticles

    NARCIS (Netherlands)

    Baig, Muhammad Irshad; Ingole, Pravin G.; Jeon, Jae deok; Hong, Seong Uk; Choi, Won Kil; Jang, Boyun; Lee, Hyung Keun

    2017-01-01

    In this work, we have reported a facile method to improve the water vapor permeation performance of thin film nanocomposite membranes by tailoring the surface properties of Silicon nanoparticles. Inductively coupled plasma technique was utilized to synthesize amorphous Silicon nanoparticles (~. 10.

  11. Analysis of combined heat and mass transfer of water-vapor in a ...

    African Journals Online (AJOL)

    Jn this paper, the combined heat and mass transfer of water-vapor into a cylindrical zeolite adsorber has been numerically simulated The twodimensional heat and mass transfer equations are numerically solved using gPROMS program - a general Process Modeling System [J] program, inserting the proper initial and ...

  12. Analysis of combined heat and mass transfer of water- Vapor in a ...

    African Journals Online (AJOL)

    In this paper, the combined heat and mass transfer of water-vapor into a cylindrical zeolite adsorber has been numerically simulated The twodimensional heat and mass transfer equations are numerically solved using gPROMS program - a general Process Modeling System {lJ program, inserting the proper initial and ...

  13. Interpretation of TOVS Water Vapor Radiances Using a Random Strong Line Model

    CERN Document Server

    Soden, B J; Soden, Brian J.; Bretherton, Francis P.

    1995-01-01

    This study illustrates the application of a random strong line (RSL) model of radiative transfer to the interpretation of satellite observations of the upwelling radiation in the 6.3 micron water vapor absorption band. The model, based upon an assemblage of randomly overlapped, strongly absorbing, pressure broadened lines, is compared to detailed radiative transfer calculations of the upper (6.7 micron) tropospheric water vapor radiance and demonstrated to be accurate to within ~ 1.2 K. Similar levels of accuracy are found when the model is compared to detailed calculations of the middle (7.3 micron) and lower (8.3 micron) tropospheric water vapor radiance, provided that the emission from the underlying surface is taken into account. Based upon these results, the RSL model is used to interpret TOVS-observed water vapor radiances in terms of the relative humidity averaged over deep layers of the upper, middle, and lower troposphere. We then present near-global maps of the geographic distribution and climatolog...

  14. Relating tropical ocean clouds to moist processes using water vapor isotope measurements

    Directory of Open Access Journals (Sweden)

    J. Lee

    2011-01-01

    Full Text Available We examine the co-variations of tropospheric water vapor, its isotopic composition and cloud types and relate these distributions to tropospheric mixing and distillation models using satellite observations from the Aura Tropospheric Emission Spectrometer (TES over the summertime tropical ocean. Interpretation of these process distributions must take into account the sensitivity of the TES isotope and water vapor measurements to variations in cloud, water, and temperature amount. Consequently, comparisons are made between cloud-types based on the International Satellite Cloud Climatology Project (ISSCP classification; these are clear sky, non-precipitating (e.g., cumulus, boundary layer (e.g., stratocumulus, and precipitating clouds (e.g. regions of deep convection. In general, we find that the free tropospheric vapor over tropical oceans does not strictly follow a Rayleigh model in which air parcels become dry and isotopically depleted through condensation. Instead, mixing processes related to convection as well as subsidence, and re-evaporation of rainfall associated with organized deep convection all play significant roles in controlling the water vapor distribution. The relative role of these moisture processes are examined for different tropical oceanic regions.

  15. Structure and Dynamical Influence of Water Vapor in the Lower Tropical Troposphere

    Science.gov (United States)

    Stevens, Bjorn; Brogniez, Hélène; Kiemle, Christoph; Lacour, Jean-Lionel; Crevoisier, Cyril; Kiliani, Johannes

    2017-11-01

    In situ, airborne and satellite measurements are used to characterize the structure of water vapor in the lower tropical troposphere—below the height, z_*, of the triple-point isotherm, T_*. The measurements are evaluated in light of understanding of how lower-tropospheric water vapor influences clouds, convection and circulation, through both radiative and thermodynamic effects. Lower-tropospheric water vapor, which concentrates in the first few kilometers above the boundary layer, controls the radiative cooling profile of the boundary layer and lower troposphere. Elevated moist layers originating from a preferred level of convective detrainment induce a profile of radiative cooling that drives circulations which reinforce such features. A theory for this preferred level of cumulus termination is advanced, whereby the difference between T_* and the temperature at which primary ice forms gives a `first-mover advantage' to glaciating cumulus convection, thereby concentrating the regions of the deepest convection and leading to more clouds and moisture near the triple point. A preferred level of convective detrainment near T_* implies relative humidity reversals below z* which are difficult to identify using retrievals from satellite-borne microwave and infrared sounders. Isotopologues retrievals provide a hint of such features and their ability to constrain the structure of the vertical humidity profile merits further study. Nonetheless, it will likely remain challenging to resolve dynamically important aspects of the vertical structure of water vapor from space using only passive sensors.

  16. Real-Time Water Vapor Maps from a GPS Surface Network: Construction, Validation, and Applications

    NARCIS (Netherlands)

    Haan, de S.; Holleman, I.; Holtslag, A.A.M.

    2009-01-01

    In this paper the construction of real-time integrated water vapor (IWV) maps from a surface network of global positioning system (GPS) receivers is presented. The IWV maps are constructed using a twodimensional variational technique with a persistence background that is 15 min old. The background

  17. Water vapor barrier and sorption properties of edible films from pullulan and rice wax.

    Science.gov (United States)

    Edible films were prepared by using various ratios of pullulan and rice wax. Freestanding composite films were obtained with up to 46.4% rice wax. Water vapor barrier properties of the film were improved with increased addition of rice wax. Moisture sorption isotherms were also studied to examine...

  18. Conversion function between the Linke turbidity and the atmospheric water vapor and aerosol content

    OpenAIRE

    Ineichen, Pierre

    2008-01-01

    This technical note presents a conversion function between the widely used Linke turbidity coefficient TL, the atmospheric water vapor and urban aerosol content. It takes into account the altitude of the application site. The function is based on radiative transfer calculations and validated with the help of an independent clear sky model. Its precision is around 0.12 units of TL.

  19. SPARC Data Initiative: Comparison of water vapor climatologies from international satellite limb sounders

    Science.gov (United States)

    Hegglin, M. I.; Tegtmeier, S.; Anderson, J.; Froidevaux, L.; Fuller, R.; Funke, B.; Jones, A.; Lingenfelser, G.; Lumpe, J.; Pendlebury, D.; Remsberg, E.; Rozanov, A.; Toohey, M.; Urban, J.; von Clarmann, T.; Walker, K. A.; Wang, R.; Weigel, K.

    2013-10-01

    Within the SPARC Data Initiative, the first comprehensive assessment of the quality of 13 water vapor products from 11 limb-viewing satellite instruments (LIMS, SAGE II, UARS-MLS, HALOE, POAM III, SMR, SAGE III, MIPAS, SCIAMACHY, ACE-FTS, and Aura-MLS) obtained within the time period 1978-2010 has been performed. Each instrument's water vapor profile measurements were compiled into monthly zonal mean time series on a common latitude-pressure grid. These time series serve as basis for the "climatological" validation approach used within the project. The evaluations include comparisons of monthly or annual zonal mean cross sections and seasonal cycles in the tropical and extratropical upper troposphere and lower stratosphere averaged over one or more years, comparisons of interannual variability, and a study of the time evolution of physical features in water vapor such as the tropical tape recorder and polar vortex dehydration. Our knowledge of the atmospheric mean state in water vapor is best in the lower and middle stratosphere of the tropics and midlatitudes, with a relative uncertainty of ±2-6% (as quantified by the standard deviation of the instruments' multiannual means). The uncertainty increases toward the polar regions (±10-15%), the mesosphere (±15%), and the upper troposphere/lower stratosphere below 100 hPa (±30-50%), where sampling issues add uncertainty due to large gradients and high natural variability in water vapor. The minimum found in multiannual (1998-2008) mean water vapor in the tropical lower stratosphere is 3.5 ppmv (±14%), with slightly larger uncertainties for monthly mean values. The frequently used HALOE water vapor data set shows consistently lower values than most other data sets throughout the atmosphere, with increasing deviations from the multi-instrument mean below 100 hPa in both the tropics and extratropics. The knowledge gained from these comparisons and regarding the quality of the individual data sets in different regions

  20. The relationship between tropospheric wave forcing and tropical lower stratospheric water vapor

    Directory of Open Access Journals (Sweden)

    S. Dhomse

    2008-02-01

    Full Text Available Using water vapor data from HALOE and SAGE II, an anti-correlation between planetary wave driving (here expressed by the mid-latitude eddy heat flux at 50 hPa added from both hemispheres and tropical lower stratospheric (TLS water vapor has been obtained. This appears to be a manifestation of the inter-annual variability of the Brewer-Dobson (BD circulation strength (the driving of which is generally measured in terms of the mid-latitude eddy heat flux, and hence amount of water vapor entering the stratosphere. Some years such as 1991 and 1997 show, however, a clear departure from the anti-correlation which suggests that the water vapor changes in TLS can not be attributed solely to changes in extratropical planetary wave activity (and its effect on the BD circulation. After 2000 a sudden decrease in lower stratospheric water vapor has been reported in earlier studies based upon satellite data from HALOE, SAGE II and POAM III indicating that the lower stratosphere has become drier since then. This is consistent with a sudden rise in the combined mid-latitude eddy heat flux with nearly equal contribution from both hemispheres as shown here and with the increase in tropical upwelling and decrease in cold point temperatures found by Randel et al. (2006. The low water vapor and enhanced planetary wave activity (in turn strength of the BD circulation has persisted until the end of the satellite data records. From a multi-variate regression analysis applied to 27 years of NCEP and HadAT2 (radiosonde temperatures (up to 2005 with contributions from solar cycle, stratospheric aerosols and QBO removed, the enhancement wave driving after 2000 is estimated to contribute up to 0.7 K cooling to the overall TLS temperature change during the period 2001–2005 when compared to the period 1996–2000. NCEP cold point temperature show an average decrease of nearly 0.4 K from changes in the wave driving, which is consistent with observed mean TLS water vapor

  1. Secondary Organic Aerosol Formation by Reactive Condensation of Glyoxal and Water Vapor

    Science.gov (United States)

    Hastings, W. P.; Koehler, C. A.; de Haan, D. O.

    2004-05-01

    The formation of secondary organic aerosol particles by particle-phase reactions is currently of great interest. Glyoxal has been identified as a significant component in the particle phase in recent smog chamber aromatic oxidation studies. This is surprising because glyoxal has a high vapor pressure and phase partitioning theory would predict that it remain almost entirely in the gas phase. Growth of inorganic seed aerosol in a particle chamber was monitored by scanning mobility particle sizing during addition of gas-phase glyoxal and small amounts of water vapor. Glyoxal was observed to condense on inorganic seed aerosol at concentrations that are at least 100 times below its vapor pressure. This behavior can be explained by a chemical reaction: glyoxal is known to polymerize when exposed to water vapor. This polymerization may be a general mechanism for secondary aerosol formation by alpha-dicarbonyl compounds. The reactivity of hydrated and polymerized forms of glyoxal during analysis by gas chromatography was assessed. Hydrated glyoxal was found to convert to glyoxal at even slightly elevated temperatures in GC injection ports. We then showed that breakdown of solid-phase glyoxal trimer dihydrate, forming gas phase glyoxal and water vapor, occurs at temperatures just above 50 *C, the boiling point of glyoxal. These observations suggest that reports of particle-phase glyoxal are likely caused by GC sampling artifacts, and that the actual particulate species are instead polymerized forms of glyoxal. It does not appear that chemical derivatization protects glyoxal polymers from thermal breakdown during GC analysis. The existence in the particle phase of glyoxal polymers with negligable vapor pressures, rather than volatile glyoxal, is consistent with phase partitioning theory.

  2. Evidence of water vapor in excess of saturation in the atmosphere of Mars.

    Science.gov (United States)

    Maltagliati, L; Montmessin, F; Fedorova, A; Korablev, O; Forget, F; Bertaux, J-L

    2011-09-30

    The vertical distribution of water vapor is key to the study of Mars' hydrological cycle. To date, it has been explored mainly through global climate models because of a lack of direct measurements. However, these models assume the absence of supersaturation in the atmosphere of Mars. Here, we report observations made using the SPICAM (Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars) instrument onboard Mars Express that provide evidence of the frequent presence of water vapor in excess of saturation, by an amount far surpassing that encountered in Earth's atmosphere. This result contradicts the widespread assumption that atmospheric water on Mars cannot exist in a supersaturated state, directly affecting our long-term representation of water transport, accumulation, escape, and chemistry on a global scale.

  3. Role of Water Vapor Content in the Effects of Aerosol on the Electrification of Thunderstorms: A Numerical Study

    Directory of Open Access Journals (Sweden)

    Pengguo Zhao

    2016-10-01

    Full Text Available We explored the role of the water vapor content below the freezing level in the response of idealized supercell storm electrical processes to increased concentrations of cloud condensation nuclei (CCN. Using the Weather Research and Forecasting model coupled with parameterizations electrification and discharging, we performed 30 simulations by varying both the CCN concentration and water vapor content below the freezing level. The sensitivity simulations showed a distinct response to increased concentrations of CCN, depending on the water vapor content below the freezing level. Enhancing CCN concentrations increased electrification processes of thunderstorms and produced a new negative charge region above the main positive charge center when there were ample amounts of water vapor below the freezing level. Conversely, there were weak effects on electrification and the charge structure in numerical experiments initialized with lower water vapor content below the freezing level.

  4. Validation of MODIS integrated water vapor product against reference GPS data at the Iberian Peninsula

    Science.gov (United States)

    Vaquero-Martínez, Javier; Antón, Manuel; Ortiz de Galisteo, José Pablo; Cachorro, Victoria E.; Costa, Maria João; Román, Roberto; Bennouna, Yasmine S.

    2017-12-01

    In this work, the water vapor product from MODIS (MODerate-resolution Imaging Spectroradiometer) instrument, on-board Aqua and Terra satellites, is compared against GPS water vapor data from 21 stations in the Iberian Peninsula as reference. GPS water vapor data is obtained from ground-based receiver stations which measure the delay caused by water vapor in the GPS microwave signals. The study period extends from 2007 until 2012. Regression analysis in every GPS station show that MODIS overestimates low integrated water vapor (IWV) data and tends to underestimate high IWV data. R2 shows a fair agreement, between 0.38 and 0.71. Inter-quartile range (IQR) in every station is around 30-45%. The dependence on several parameters was also analyzed. IWV dependence showed that low IWV are highly overestimated by MODIS, with high IQR (low precision), sharply decreasing as IWV increases. Regarding dependence on solar zenith angle (SZA), performance of MODIS IWV data decreases between 50° and 90°, while night-time MODIS data (infrared) are quite stable. The seasonal cycles of IWV and SZA cause a seasonal dependence on MODIS performance. In summer and winter, MODIS IWV tends to overestimate the reference IWV value, while in spring and autumn the tendency is to underestimate. Low IWV from coastal stations is highly overestimated (∼60%) and quite imprecise (IQR around 60%). On the contrary, high IWV data show very little dependence along seasons. Cloud-fraction (CF) dependence was also studied, showing that clouds display a negligible impact on IWV over/underestimation. However, IQR increases with CF, except in night-time satellite values, which are quite stable.

  5. Correlation among Cirrus Ice Content, Water Vapor and Temperature in the TTL as Observed by CALIPSO and Aura-MLS

    Science.gov (United States)

    Flury, T.; Wu, D. L.; Read, W. G.

    2012-01-01

    Water vapor in the tropical tropopause layer (TTL) has a local radiative cooling effect. As a source for ice in cirrus clouds, however, it can also indirectly produce infrared heating. Using NASA A-Train satellite measurements of CALIPSO and Aura/MLS we calculated the correlation of water vapor, ice water content and temperature in the TTL. We find that temperature strongly controls water vapor (correlation r =0.94) and cirrus clouds at 100 hPa (r = -0.91). Moreover we observe that the cirrus seasonal cycle is highly (r =-0.9) anticorrelated with the water vapor variation in the TTL, showing higher cloud occurrence during December-January-February. We further investigate the anticorrelation on a regional scale and find that the strong anticorrelation occurs generally in the ITCZ (Intertropical Convergence Zone). The seasonal cycle of the cirrus ice water content is also highly anticorrelated to water vapor (r = -0.91) and our results support the hypothesis that the total water at 100 hPa is roughly constant. Temperature acts as a main regulator for balancing the partition between water vapor and cirrus clouds. Thus, to a large extent, the depleting water vapor in the TTL during DJF is a manifestation of cirrus formation.

  6. Water vaporization promotes coseismic fluid pressurization and buffers temperature rise

    NARCIS (Netherlands)

    Chen, Jianye|info:eu-repo/dai/nl/370819071; Niemeijer, André|info:eu-repo/dai/nl/370832132; Yao, Lu; Ma, Shengli

    2017-01-01

    We investigated the frictional properties of carbonate-rich gouge layers at a slip rate of 1.3 m/s, under dry and water-saturated conditions, while monitoring temperature at different locations on one of the gouge-host rock interfaces. All experiments showed a peak frictional strength of 0.4–0.7,

  7. Velocity profile of water vapor inside a cavity with two axial inlets and two outlets

    Science.gov (United States)

    Guadarrama-Cetina, José; Ruiz Chavarría, Gerardo

    2014-03-01

    To study the dynamics of Breath Figure phenomenon, a control of both the rate of flow and temperature of water vapor is required. The experimental setup widely used is a non hermetically closed chamber with cylindrical geometry and axial inlets and outlets. In this work we present measurements in a cylindrical chamber with diameter 10 cm and 1.5 cm height, keeping a constant temperature (10 °C). We are focused in the velocity field when a gradient of the temperatures is produced between the base plate and the vapor. With a flux of water vapor of 250 mil/min at room temperature (21 °C), the Reynolds number measured in one inlet is 755. Otherwise, the temperatures of water vapor varies from 21 to 40 °C. The velocity profile is obtained by hot wire anemometry. We identify the stagnations and the possibly instabilities regions for an empty plate and with a well defined shape obstacle as a fashion sample. Facultad de Ciencias, UNAM.

  8. An Analytical Formula for Potential Water Vapor in an Atmosphere of Constant Lapse Rate

    Directory of Open Access Journals (Sweden)

    Ali Varmaghani

    2012-01-01

    Full Text Available Accurate calculation of precipitable water vapor (PWV in the atmosphere has always been a matter of importance for meteorologists. Potential water vapor (POWV or maximum precipitable water vapor can be an appropriate base for estimation of probable maximum precipitation (PMP in an area, leading to probable maximum flood (PMF and flash flood management systems. PWV and POWV have miscellaneously been estimated by means of either discrete solutions such as tables, diagrams or empirical methods; however, there is no analytical formula for POWV even in a particular atmospherical condition. In this article, fundamental governing equations required for analytical calculation of POWV are first introduced. Then, it will be shown that this POWV calculation relies on a Riemann integral solution over a range of altitude whose integrand is merely a function of altitude. The solution of the integral gives rise to a series function which is bypassed by approximation of saturation vapor pressure in the range of -55 to 55 degrees Celsius, and an analytical formula for POWV in an atmosphere of constant lapse rate is proposed. In order to evaluate the accuracy of the suggested equation, exact calculations of saturated adiabatic lapse rate (SALR at different surface temperatures were performed. The formula was compared with both the diagrams from the US Weather Bureau and SALR. The results demonstrated unquestionable capability of analytical solutions and also equivalent functions.

  9. Attenuation of concentration fluctuations of water vapor and other trace gases in turbulent tube flow

    DEFF Research Database (Denmark)

    Massman, W.J.; Ibrom, Andreas

    2008-01-01

    the turbulent tube flow issue for both passive and sorbing tracers with the intent of developing a physically-based semi-empirical model that describes the attenuation associated with water vapor fluctuations. Toward this end, we develop a new model of tube flow dynamics (radial profiles of the turbulent...... diffusivity and tube airstream velocity). We compare our new passive-tracer formulation with previous formulations in a systematic and unified way in order to assess how sensitive the passive-tracer results depend on fundamental modeling assumptions. We extend the passive tracer model to the vapor sorption....../desorption case by formulating the model's wall boundary condition in terms of a physically-based semi-empirical model of the sorption/desorption vapor fluxes. Finally we synthesize all modeling and observational results into a single analytical expression that captures the effects of the mean ambient humidity...

  10. Energy and water vapor transport across a simplified cloud-clear air interface

    CERN Document Server

    Gallana, Luca; De Santi, Francesca; Iovieno, Michele; Tordella, Daniela

    2015-01-01

    We consider a simplified physics of the could interface where condensation, evaporation and radiation are neglected and momentum, thermal energy and water vapor transport is represented in terms of the Boussinesq model coupled to a passive scalar transport equation for the vapor. The interface is modeled as a layer separating two isotropic turbulent regions with different kinetic energy and vapor concentration. In particular, we focus on the small scale part of the inertial range as well as on the dissipative range of scales which are important to the micro-physics of warm clouds. We have numerically investigated stably stratified interfaces by locally perturbing at an initial instant the standard temperature lapse rate at the cloud interface and then observing the temporal evolution of the system. When the buoyancy term becomes of the same order of the inertial one, we observe a spatial redistribution of the kinetic energy which produce a concomitant pit of kinetic energy within the mixing layer. In this sit...

  11. Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Westwater, Edgeworth

    2011-05-06

    The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both microwave radiometers (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable Water Vapor (PWV) and Liquid Water Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of water vapor, this is especially important during the Arctic winter, when PWV is frequently less than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - Water Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the radiometer group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning Radiometer (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved water vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of radiometers to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of microwave and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third year of

  12. Method for the production of hydrogen from water vapor

    Energy Technology Data Exchange (ETDEWEB)

    Seitzer, W.H.

    1975-05-07

    The invention concerns a one-stage method for thermal water dissociation and the removal of the oxygen from the resulting oxyhydrogen gas. According to the invention a) the wet oxyhydrogen gas is led past a wall made of hard-to-melt oxide, preferably zirconium oxide, which allows the penetration of oxygen, b) the oxygen diffusing through the wall is continuously removed by reaction with a reducing gas, and c) the thus produced reaction heat is used to heat the plant.

  13. Water vapor weathering of Taurus-Littrow orange soil - A pore-structure analysis

    Science.gov (United States)

    Cadenhead, D. A.; Mikhail, R. S.

    1975-01-01

    A pore-volume analysis was performed on water vapor adsorption data previously obtained on a fresh sample of Taurus-Littrow orange soil, and the analysis was repeated on the same sample after its exposure to moist air for a period of approximately six months. The results indicate that exposure of an outgassed sample to high relative pressures of water vapor can result in the formation of substantial micropore structure, the precise amount being dependent on the sample pretreatment, particularly the outgassing temperature. Micropore formation is explained in terms of water penetration into surface defects. In contrast, long-term exposure to moist air at low relative pressures appears to reverse the process with the elimination of micropores and enlargement of mesopores possibly through surface diffusion of metastable adsorbent material. The results are considered with reference to the storage of lunar samples.

  14. Influence of dehydration temperature on water vapor adsorption, dissolution behavior and surface property of ampicillin.

    Science.gov (United States)

    Moribe, Kunikazu; Wongmekiat, Arpansiree; Hyakutake, Yuki; Tozuka, Yuichi; Oguchi, Toshio; Yamamoto, Keiji

    2005-01-20

    Several specimens of anhydrous ampicillin were prepared by heating the ampicillin trihydrate at 100, 120, 140 and 160 degrees C. The effects of dehydration temperature on water vapor adsorption, dissolution behavior and surface property were investigated. The water vapor adsorption of anhydrous ampicillin was studied at 89% relative humidity, 40 degrees C and the water vapor adsorption rate was found to decrease with increase of dehydration temperature. Dissolution profiles of the various anhydrous specimens were investigated in 96% ethanol at 35 degrees C by the static disk method. The anhydrous form prepared at higher dehydration temperature exhibited faster dissolution rate. Solid phase transformation from the anhydrous form to the trihydrate form occurred during the dissolution test. The rate of phase transformation during the dissolution test decreased with increasing dehydration temperature. Topographic difference of the anhydrous forms prepared at 100 and 160 degrees C was not observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM); however, difference of the microstructural properties was apparently observed by the AFM phase image. Surface free energy study revealed that when ampicillin was dehydrated at high temperature, the sample surface became more hydrophobic resulting in less interaction force with water and slow water sorption rate. From the results, we concluded that the polarity of sample surface induced by dehydration of ampicillin would affect the phase transformation and dissolution behavior.

  15. Oxidation of uranium in low partial pressures of oxygen and water vapor at 100/sup 0/C

    Energy Technology Data Exchange (ETDEWEB)

    Weirick, L J

    1984-06-01

    Oxygen isotope studies indicate that a previously proposed theory describing the oxidation of uranium is incorrect. This theory had proposed that the uranium reacted directly with water vapor to form uranium dioxide and hydrogen and the hydrogen subsequently reacted with the free oxygen to form water. This study shows that oxygen reacts directly with uranium, the role of water vapor being to affect the uranium oxide structure which is formed. The reaction rate of uranium with water vapor in the absence of oxygen was linear and proportional to the water vapor pressure for water vapor pressures between 2 and 20 Torr. Hydrogen was produced by the reaction at a rate of almost two moles for every one mole of uranium dioxide formed. The oxide was identified as UO/sub 2/ /sub 0/. The reaction of uranium with water vapor in the presence of oxygen showed three separate regions of reaction response. In one region, at low oxygen pressure, the reaction was the same as with no oxygen, a second region at oxygen pressures between 0.05 and 1 Torr was a transition stage and in the third region, at oxygen pressures above 1 Torr, the reaction rate was linear and independent of both oxygen and water vapor pressure. The oxide formed was identified as nominally U/sub 4/O/sub 9/. Only a small amount of hydrogen was produced.

  16. Water liquid-vapor interface subjected to various electric fields: A molecular dynamics study

    Science.gov (United States)

    Nikzad, Mohammadreza; Azimian, Ahmad Reza; Rezaei, Majid; Nikzad, Safoora

    2017-11-01

    Investigation of the effects of E-fields on the liquid-vapor interface is essential for the study of floating water bridge and wetting phenomena. The present study employs the molecular dynamics method to investigate the effects of parallel and perpendicular E-fields on the water liquid-vapor interface. For this purpose, density distribution, number of hydrogen bonds, molecular orientation, and surface tension are examined to gain a better understanding of the interface structure. Results indicate enhancements in parallel E-field decrease the interface width and number of hydrogen bonds, while the opposite holds true in the case of perpendicular E-fields. Moreover, perpendicular fields disturb the water structure at the interface. Given that water molecules tend to be parallel to the interface plane, it is observed that perpendicular E-fields fail to realign water molecules in the field direction while the parallel ones easily do so. It is also shown that surface tension rises with increasing strength of parallel E-fields, while it reduces in the case of perpendicular E-fields. Enhancement of surface tension in the parallel field direction demonstrates how the floating water bridge forms between the beakers. Finally, it is found that application of external E-fields to the liquid-vapor interface does not lead to uniform changes in surface tension and that the liquid-vapor interfacial tension term in Young's equation should be calculated near the triple-line of the droplet. This is attributed to the multi-directional nature of the droplet surface, indicating that no constant value can be assigned to a droplet's surface tension in the presence of large electric fields.

  17. Airborne Lidar Observations of Water Vapor Variability in Tropical Shallow Convective Environment

    Science.gov (United States)

    Kiemle, Christoph; Groß, Silke; Wirth, Martin; Bugliaro, Luca

    2017-10-01

    An airborne downward-pointing water vapor lidar provides two-dimensional, simultaneous curtains of atmospheric backscatter and humidity along the flight track with high accuracy and spatial resolution. In order to improve the knowledge on the coupling between clouds, circulation and climate in the trade wind region, the DLR (Deutsches Zentrum für Luft- und Raumfahrt) water vapor lidar was operated on board the German research aircraft HALO during the NARVAL (Next Generation Aircraft Remote Sensing for Validation Studies) field experiment in December 2013. Out of the wealth of about 30 flight hours or 25,000 km of data over the Tropical Atlantic Ocean east of Barbados, three 2-h-long, representative segments from different flights were selected. Analyses of Meteosat Second Generation images and dropsondes complement this case study. All observations indicate a high heterogeneity of the humidity in the lowest 4 km of the tropical troposphere, as well as of the depth of the cloud (1-2 km thick) and sub-cloud layer ( 1 km thick). At the winter trade inversion with its strong humidity jump of up to 9 g/kg in water vapor mixing ratio, the mixing ratio variance can attain 9 (g/kg)2, while below it typically ranges between 1 and 3 (g/kg)2. Layer depths and partial water vapor columns within the layers vary by up to a factor of 2. This affects the total tropospheric water vapor column, amounting on average to 28 kg/m2, by up to 10 kg/m2 or 36%. The dominant scale of the variability is given by the extent of regions with higher-than-average humidity and lies between 300 and 600 km. The variability mainly stems from the alternation between dry regions and moisture lifted by convection. Occasionally, up to 100-km large dry regions are observed. In between, convection pushes the trade inversion upward, sharpening the vertical moisture gradient that is colocated with the trade inversion. In most of the water vapor profiles, this gradient is stronger than the one located at the

  18. Airborne Lidar Observations of Water Vapor Variability in the Northern Atlantic Trades

    Science.gov (United States)

    Kiemle, Christoph; Groß, Silke; Wirth, Martin; Bugliaro, Luca

    2017-04-01

    During the NARVAL (Next Generation Aircraft Remote Sensing for Validation Studies) field experiments in December 2013 and August 2016 the DLR lidar WALES (Water vapor Lidar Experiment in Space) was operated on board the German research aircraft HALO. The lidar simultaneously provided two-dimensional curtains of atmospheric backscatter and humidity along the flight track with high accuracy and spatial resolution, in order to help improve our knowledge on the coupling between water vapor, clouds, and circulation in the trades. The variability of water vapor, ubiquitous in our measurements, poses challenges to climate models because it acts on the small-scale low-cloud cover. Aloft, the very dry free troposphere in the subsiding branch of the Hadley cell acts as an open window in a greenhouse, efficiently cooling the lower troposphere. Secondary circulations between radiatively heated and cooled regions are supposed to occur, adding complexity to the situation. After recently having identified them to be mainly responsible for the uncertainty in global climate sensitivity, such interactions between shallow convection, circulation and radiation are at the heart of present scientific debate, endorsed by the WCRP (World Climate Research Programme) "Grand Challenge on Clouds, Circulation and Climate Sensitivity". Out of the wealth of about 30 winter and 60 summer flight hours totaling 75000 km of data over the Tropical Atlantic Ocean east of Barbados, several representative lidar segments from different flights are presented, together with Meteosat Second Generation (MSG) images and dropsonde profiles. All observations indicate high heterogeneity of the humidity in the lowest 5 km, as well as high variability of the depth of the cloud layer (1 - 2 km thick) and of the sub-cloud boundary layer ( 1 km thick). Layer depths and partial water vapor columns within the layers may vary by up to a factor of 2, and on a large range of horizontal scales. Occasionally, very dry, up

  19. In-Situ Water Vapor Probe for a Robot Arm-Mounted, Compact Water Vapor Analyzer: Preliminary Results

    Science.gov (United States)

    Socki, Richard A.; Niles, Paul B.; Cabiran, Mike; Rossi, Chris; Sun, Tao

    2013-01-01

    This work describes the ongoing development of an instrument package for the in-situ detection and isotopic analysis of water (from ice, icy soils, and hydrated minerals) on future lunar, asteroid, or martian exploration missions. This instrument is intended to be mounted on a robotic arm and be brought to the sample, rather than necessitating expensive and complicated sample handling to bring the sample to the instrument.

  20. Use of a novel new irrigation system to observe and model water vapor flow through dry soils

    Science.gov (United States)

    Todman, L. C.; Ireson, A. M.; Butler, A. P.; Templeton, M.

    2013-12-01

    In dry soils hydraulic connectivity within the liquid water phase decreases and vapor flow becomes a significant transport mechanism for water. The temperature or solute concentration of the liquid phase affects the vapor pressure of the surrounding air, thus temperature or solute gradients can drive vapor flows. However, in extremely dry soils where water is retained by adsorption rather than capillarity, vapor flows can also occur. In such soils tiny changes in water content significantly affect the equilibrium vapor pressure in the soil, and hence small differences in water content can initiate vapor pressure gradients. In many field conditions this effect may be negligible compared to vapor flows driven by other factors. However, flows of this type are particularly significant in a new type of subsurface irrigation system which uses pervaporation, via a polymer tubing, as the mechanism for water supply. In this system, water enters the soil in vapor phase. Experiments using this system therefore provide a rare opportunity to observe vapor flows initiating from a subsurface source without significant injection of heat. A model was developed to simulate water flow through the soil in liquid and vapor phase. In this model it was assumed that the two phases were in equilibrium. The equilibrium relationship was defined by a new mathematical expression that was developed to fit experimental data collected to characterize the sorption isotherm of three soils (sand, saline sand and top soil). The osmotic potential of the saline sand was defined as a function of water content using a continuous mathematical expression. The model was then calibrated to fit the data from laboratory experiments, in which the vapor flow into and out of the soil were quantified. The model successfully reproduced experimental observations of the total water flux, relative humidity and water content distribution in three soil types. This suggests that the model, including the proposed

  1. Effect of Water Vapor, Temperature, and Rapid Annealing on Formamidinium Lead Triiodide Perovskite Crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Jeffery A.; Wozny, Sarah; Alkurd, Nooraldeen R.; Yang, Mengjin; Kovarik, Libor; Holesinger, Terry G.; Al-Jassim, Mowafak; Zhu, Kai; Zhou, Weilie; Berry, Joseph J.

    2016-07-08

    Perovskite-based solar cells are one of the emerging candidates for radically lower cost photovoltaics. Herein, we report on the synthesis and crystallization of organic-inorganic formamidinium lead triiodide perovskite films under controlled atmospheric and environmental conditions. Using in situ (scanning) transmission electron microscopy, we make observations of the crystallization process of these materials in nitrogen and oxygen gas with and without the presence of water vapor. Complementary planar samples were also fabricated in the presence of water vapor and characterized by in situ X-ray diffraction. Direct observations of the material structure and final morphology indicate that the exposure to water vapor results in a porous film that is metastable, regardless of the presence of argon, nitrogen, or oxygen. However, the optimal crystallization temperature of 175 degrees C is unperturbed across conditions. Rapid modulation about the annealing temperature of 175 degrees C in +/-25 degrees C steps (150-200 degrees C) promotes crystallization and significantly improves the film morphology by overcoming the presence of impregnated water trapped in the material. Following this processing protocol, we demonstrate substantial growth to micron-size grains via observation inside of an environmentally controlled transmission electron microscope. Adapting this insight from our in situ microscopy, we are able to provide an informed materials protocol to control the structure and morphology of these organic-inorganic semiconductors, which is readily applicable to benchtop device growth strategies.

  2. Effect of Water Vapor, Temperature, and Rapid Annealing on Formamidinium Lead Triiodide Perovskite Crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Jeffery A.; Wozny, Sarah; Alkurd, Nooraldeen R.; Yang, Mengjin; Kovarik, Libor; Holesinger, Terry; Al-Jassim, Mowafak M.; Zhu, Kai; Zhou, Weilie; Berry, J. J.

    2016-07-08

    Perovskite-based solar cells are one of the emerging candidates for radically lower cost photovoltaics. Herein, we report on the synthesis and crystallization of organic-inorganic formamidinium lead triiodide perovskite films under controlled atmospheric and environmental conditions. Using in situ (scanning) transmission electron microscopy, we make observations of the crystallization process of these materials in nitrogen and oxygen gas with and without the presence of water vapor. Complementary planar samples were also fabricated in the presence of water vapor and characterized by in situ X-ray diffraction. Direct observations of the material structure and final morphology indicate that the exposure to water vapor results in a porous film that is metastable, regardless of the presence of argon, nitrogen, or oxygen. However, the optimal crystallization temperature of 175 °C is unperturbed across conditions. Rapid modulation about the annealing temperature of 175 °C in ±25 °C steps (150-200 °C) promotes crystallization and significantly improves the film morphology by overcoming the presence of impregnated water trapped in the material. Following this processing protocol, we demonstrate substantial growth to micron-size grains via observation inside of an environmentally controlled transmission electron microscope. Adapting this insight from our in situ microscopy, we are able to provide an informed materials protocol to control the structure and morphology of these organic-inorganic semiconductors, which is readily applicable to benchtop device growth strategies.

  3. Synthesis of Hydrophobic Mesoporous Material MFS and Its Adsorption Properties of Water Vapor

    Directory of Open Access Journals (Sweden)

    Guotao Zhao

    2014-01-01

    Full Text Available Fluorine-containing hydrophobic mesoporous material (MFS with high surface area is successfully synthesized with hydrothermal synthesis method by using a perfluorinated surfactant SURFLON S-386 template. The adsorption properties of water vapor on the synthesized MFS are also investigated by using gravimetric method. Results show that SEM image of the MFS depicted roundish morphology with the average crystal size of 1-2 μm. The BET surface area and total pore volume of the MFS are 865.4 m2 g−1 and 0.74 cm3 g−1 with a narrow pore size distribution at 4.9 nm. The amount of water vapor on the MFS is about 0.41 mmol g−1 at 303 K, which is only 52.6% and 55.4% of MCM-41 and SBA-15 under the similar conditions, separately. The isosteric adsorption heat of water on the MFS is gradually about 27.0–19.8 kJ mol−1, which decreases as the absorbed water vapor amount increases. The value is much smaller than that on MCM-41 and SBA-15. Therefore, the MFS shows more hydrophobic surface properties than the MCM-41 and SBA-15. It may be a kind of good candidate for adsorption of large molecule and catalyst carrier with high moisture resistance.

  4. Continuous monitoring of summer surface water vapor isotopic composition above the Greenland Ice Sheet

    Directory of Open Access Journals (Sweden)

    H. C. Steen-Larsen

    2013-05-01

    Full Text Available We present here surface water vapor isotopic measurements conducted from June to August 2010 at the NEEM (North Greenland Eemian Drilling Project camp, NW Greenland (77.45° N, 51.05° W, 2484 m a.s.l.. Measurements were conducted at 9 different heights from 0.1 m to 13.5 m above the snow surface using two different types of cavity-enhanced near-infrared absorption spectroscopy analyzers. For each instrument specific protocols were developed for calibration and drift corrections. The inter-comparison of corrected results from different instruments reveals excellent reproducibility, stability, and precision with a standard deviations of ~ 0.23‰ for δ18O and ~ 1.4‰ for δD. Diurnal and intraseasonal variations show strong relationships between changes in local surface humidity and water vapor isotopic composition, and with local and synoptic weather conditions. This variability probably results from the interplay between local moisture fluxes, linked with firn–air exchanges, boundary layer dynamics, and large-scale moisture advection. Particularly remarkable are several episodes characterized by high (> 40‰ surface water vapor deuterium excess. Air mass back-trajectory calculations from atmospheric analyses and water tagging in the LMDZiso (Laboratory of Meteorology Dynamics Zoom-isotopic atmospheric model reveal that these events are associated with predominant Arctic air mass origin. The analysis suggests that high deuterium excess levels are a result of strong kinetic fractionation during evaporation at the sea-ice margin.

  5. Monitoring the water vapor isotopic composition in the temperate North Atlantic

    Science.gov (United States)

    Sveinbjörnsdottir, Arny E.; Steen-Larsen, Hans Christian; Jonsson, Thorsteinn; Johnsen, Sigfus J.

    2013-04-01

    Water stable isotopes have during many decades been used as climate proxies and indicators for variations in the hydrological cycle. However we are to a great extent still using simple empirical relationships without any deeper theoretical understanding. In order to properly relate changes in the climate and hydrological cycle to changes in the observed stable water isotopic signal we must understand the underlying physical processes. Furthermore it is a challenge for General Climate Models to adequately represent the isotopes in the hydrological cycle because of lack of in-situ measurements of the atmospheric water-vapor composition in the source regions. During the fall of 2010 we installed an autonomous water vapor spectroscopy laser (from Los Gatos Research) in a lighthouse on the South Coast of Iceland (63.83 N 21.47W) with the plan to be operational for several years. The purpose of this installation was through monitoring of the water vapor isotopic composition to understand the physical processes governing the isotopic composition of the water vapor evaporated from the ocean as well as the processes of mixing between the free troposphere and marine boundary layer. Because of the remoteness of the monitoring site and simple topography we are able to isolate the 'fingerprint' on the isotopic signal in the water vapor from respectively the ocean and the interior highland leading to a near perfect case-study area. Using back-trajectories we find a strong influence of the origin of the air masses on the measured isotopic composition. The mixing of the marine-boundary layer is found to strongly influence the measured isotopic composition. The second order isotopic parameter, d-excess, is contrary to theory and previous observations found not to depend on the relative humidity. However we do find a good correlation between the d-excess and the measured isotopic composition. We speculate that the lack of correlation between d-excess and relative humidity can be

  6. Calculation of Liquid Water-Hydrate-Methane Vapor Phase Equilibria from Molecular Simulations

    DEFF Research Database (Denmark)

    Jensen, Lars; Thomsen, Kaj; von Solms, Nicolas

    2010-01-01

    Monte Carlo simulation methods for determining fluid- and crystal-phase chemical potentials are used for the first time to calculate liquid water-methane hydrate-methane vapor phase equilibria from knowledge of atomistic interaction potentials alone. The water and methane molecules are modeled...... potential of the zero-occupancy hydrate system using thermodynamic integration from an Einstein crystal reference state, and (iii) thermodynamic integration to obtain the water and guest molecules' chemical potentials as a function of the hydrate occupancy. The three-phase equilibrium curve is calculated...... value at corresponding conditions. While computationally intensive, simulations such as these are essential to map the thermodynamically stable conditions for hydrate systems....

  7. Adsorptive water removal from dichloromethane and vapor-phase regeneration of a molecular sieve 3A packed bed

    OpenAIRE

    Jovic, S Slavisa; Laxminarayan, Y; Keurentjes, JTF Jos; Schouten, JC Jaap; Schaaf, van der, S.

    2017-01-01

    The drying of dichloromethane with a molecular sieve 3A packed bed process is modeled and experimentally verified. In the process, the dichloromethane is dried in the liquid phase and the adsorbent is regenerated by water desorption with dried dichloromethane product in the vapor phase. Adsorption equilibrium experiments show that dichloromethane does not compete with water adsorption, because of size exclusion; the pure water vapor isotherm from literature provides an accurate representation...

  8. Water Vapor Sorption Properties of Polyethylene Terephthalate over a Wide Range of Humidity and Temperature.

    Science.gov (United States)

    Dubelley, Florence; Planes, Emilie; Bas, Corine; Pons, Emmanuelle; Yrieix, Bernard; Flandin, Lionel

    2017-03-02

    The dynamic and equilibrium water vapor sorption properties of amorphous polyethylene terephthalate were determined via gravimetric analysis over a wide range of temperatures (23-70 °C) and humidities (0-90% RH). At low temperature and relative humidity, the dynamics of the sorption process was Fickian. Increasing the temperature or relative humidity induced a distinct up-swing effect, which was associated with a plasticization/clustering phenomenon. For high temperatures and relative humidity, a densification of the polymer was evidenced. In addition to the classical Fickian diffusion, a new parameter was introduced to express the structural modifications of PET. Finally, two partial pressures were defined as thresholds that control the transition between these three phases. A simplified state diagram was finally proposed. In addition, the thermal dependence of these sorption modes was also determined and reported. The enthalpy of Henry's water sorption and the activation energy of diffusion were independent of vapor pressure and followed an Arrhenius law.

  9. Theoretical study of adsorption of water vapor on surface of metallic uranium

    CERN Document Server

    Xiong Bi Tao; Xue Wei Dong; Zhu Zheng He; Jiang Gang; Wang Hong Yan; Gao Tao

    2002-01-01

    According to the experimental data, there is an intermediate substance that formed in the initial stage of oxidation reaction when water vapor is absorbed onto the metallic uranium. The minimum energy of UOH sub 2 witch C sub 2 subupsilon configuration is obtained in the state of sup 5 A sub 1 by B3LYP method of the density function theory (DFT), which is consistent with that by statics of atoms and molecules reaction (AMRS) and group theory. The results from calculations indicate that the adsorption of water vapor on the metallic uranium is an exothermic reaction and that the adsorbed amount decreases with the elevated temperatures. The adsorptive heat at 1 atm is -205.4747 kJ centre dot mol sup - sup 1 , which indicates a typical chemical adsorption

  10. Interaction of a sodium ion with the water liquid-vapor interface

    Science.gov (United States)

    Wilson, M. A.; Pohorille, A.; Pratt, L. R.; MacElroy, R. D. (Principal Investigator)

    1989-01-01

    Molecular dynamics results are presented for the density profile of a sodium ion near the water liquid-vapor interface at 320 K. These results are compared with the predictions of a simple dielectric model for the interaction of a monovalent ion with this interface. The interfacial region described by the model profile is too narrow and the profile decreases too abruptly near the solution interface. Thus, the simple model does not provide a satisfactory description of the molecular dynamics results for ion positions within two molecular diameters from the solution interface where appreciable ion concentrations are observed. These results suggest that surfaces associated with dielectric models of ionic processes at aqueous solution interfaces should be located at least two molecular diameters inside the liquid phase. A free energy expense of about 2 kcal/mol is required to move the ion within two molecular layers of the free water liquid-vapor interface.

  11. Water-vapor conductance of testudinian and crocodilian eggs (class reptilia).

    Science.gov (United States)

    Packard, G C; Taigen, T L; Packard, M J; Shuman, R D

    1979-09-01

    Flexible-shelled eggs of snapping turtles (Chelydra serpentina) have conductances to water vapor that are 55 times higher than predicted for avian eggs of similar size, whereas rigid-shelled eggs of softshell turtles (Trionyx spiniferus) and American alligators (Alligator mississippiensis) have conductances that are only five times higher than expected for comparable eggs of birds. The differences between empirical and predicted values result from the much higher effective pore areas in reptilian eggshells than in those of birds. The relatively high porosities of these reptilian eggs presumably facilitate the transport of oxygen and carbon dioxide eggshells in later stages of incubation when air trapped inside nest chambers may become hypoxic and hypercapnic, yet seem not to lead to excessive transpiration of water vapor owing to the high humidities in nests where incubation occurs.

  12. Vapor-liquid phase equilibria of water modelled by a Kim-Gordon potential

    Energy Technology Data Exchange (ETDEWEB)

    Maerzke, K A; McGrath, M J; Kuo, I W; Tabacchi, G; Siepmann, J I; Mundy, C J

    2009-03-16

    Gibbs ensemble Monte Carlo simulations were carried out to investigate the properties of a frozen-electron-density (or Kim-Gordon, KG) model of water along the vapor-liquid coexistence curve. Because of its theoretical basis, such a KG model provides for seamless coupling to Kohn-Sham density functional theory for use in mixed quantum mechanics/molecular mechanics (QM/MM) implementations. The Gibbs ensemble simulations indicate rather limited transferability of such a simple KG model to other state points. Specifically, a KG model that was parameterized by Barker and Sprik to the properties of liquid water at 300 K, yields saturated vapor pressures and a critical temperature that are significantly under- and over-estimated, respectively.

  13. Effect of Water Vapor on High-Temperature Corrosion under Conditions Mimicking Biomass Firing

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2015-01-01

    The variable flue gas composition in biomass-fired plants, among other parameters, contributes to the complexityof high-temperature corrosion of materials. Systematic parameter studies are thus necessary to understand the underlyingcorrosion mechanisms. This paper investigates the effect of water...... atmospherecontaining either 3 or 13 vol % H2O vapor. Comprehensive characterization of the corrosion products was carried out by thecomplementary use of microscopic, spectroscopic, and diffraction-based techniques. To evaluate the effect of the exposure time,results were compared to previous results with longer...... isothermal exposure over 168 h and indicated that the development of aNi-rich layer as a result of selective attack was time-dependent. The increase in the water vapor decreased the measurablecorrosion attack, and in addition, decreased sulfation was observed. Results from the current investigation and from...

  14. Application of water vapor sorption measurements for porosity characterization of hardened cement pastes

    DEFF Research Database (Denmark)

    Wu, Min; Johannesson, Björn; Geiker, Mette Rica

    2014-01-01

    Water vapor sorption can be used to study important properties of porous materials including specific surface area and pore size distribution (PSD). However, the data analysis is somewhat inconsistent in literature. In this work, the important factors influencing the analyzed results using sorption...... data were reviewed. Water vapor sorption measurements were then applied to two hardened cement pastes and one model porous material MCM-41. The specific surface area was calculated based on different equations accounting for multilayer adsorption and the PSD was analyzed from both the absorption...... and the desorption isotherms for comparison: The calculated specific surface area was quite dependent on which equation is considered for multilayer adsorption. For the studied hardened cement pastes, three characteristic peaks were found in the calculated PSD curves from the desorption isotherms with corresponding...

  15. Investigating the effects of methanol-water vapor mixture on a PBI-based high temperature PEM fuel cell

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Nielsen, Heidi Venstrup

    2012-01-01

    This paper investigates the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC). A H3PO4-doped polybenzimidazole (PBI) membrane electrode assembly (MEA), Celtec P2100 of 45 cm2 of active surface area from BASF was employed....... A long-term durability test of around 1250 h was performed, in which the concentrations of methanol-water vapor mixture in the anode feed gas were varied. The fuel cell showed a continuous performance decay in the presence of vapor mixtures of methanol and water of 5% and 8% by volume in anode feed...

  16. Atmospheric absorption model for dry air and water vapor at microwave frequencies below 100 GHz derived from spaceborne radiometer observations

    Science.gov (United States)

    Wentz, Frank J.; Meissner, Thomas

    2016-05-01

    The Liebe and Rosenkranz atmospheric absorption models for dry air and water vapor below 100 GHz are refined based on an analysis of antenna temperature (TA) measurements taken by the Global Precipitation Measurement Microwave Imager (GMI) in the frequency range 10.7 to 89.0 GHz. The GMI TA measurements are compared to the TA predicted by a radiative transfer model (RTM), which incorporates both the atmospheric absorption model and a model for the emission and reflection from a rough-ocean surface. The inputs for the RTM are the geophysical retrievals of wind speed, columnar water vapor, and columnar cloud liquid water obtained from the satellite radiometer WindSat. The Liebe and Rosenkranz absorption models are adjusted to achieve consistency with the RTM. The vapor continuum is decreased by 3% to 10%, depending on vapor. To accomplish this, the foreign-broadening part is increased by 10%, and the self-broadening part is decreased by about 40% at the higher frequencies. In addition, the strength of the water vapor line is increased by 1%, and the shape of the line at low frequencies is modified. The dry air absorption is increased, with the increase being a maximum of 20% at the 89 GHz, the highest frequency considered here. The nonresonant oxygen absorption is increased by about 6%. In addition to the RTM comparisons, our results are supported by a comparison between columnar water vapor retrievals from 12 satellite microwave radiometers and GPS-retrieved water vapor values.

  17. Short-range precipitation forecasts using assimilation of simulated satellite water vapor profiles and column cloud liquid water amounts

    Science.gov (United States)

    Wu, Xiaohua; Diak, George R.; Hayden, Cristopher M.; Young, John A.

    1995-01-01

    These observing system simulation experiments investigate the assimilation of satellite-observed water vapor and cloud liquid water data in the initialization of a limited-area primitive equations model with the goal of improving short-range precipitation forecasts. The assimilation procedure presented includes two aspects: specification of an initial cloud liquid water vertical distribution and diabatic initialization. The satellite data is simulated for the next generation of polar-orbiting satellite instruments, the Advanced Microwave Sounding Unit (AMSU) and the High-Resolution Infrared Sounder (HIRS), which are scheduled to be launched on the NOAA-K satellite in the mid-1990s. Based on cloud-top height and total column cloud liquid water amounts simulated for satellite data a diagnostic method is used to specify an initial cloud water vertical distribution and to modify the initial moisture distribution in cloudy areas. Using a diabatic initialization procedure, the associated latent heating profiles are directly assimilated into the numerical model. The initial heating is estimated by time averaging the latent heat release from convective and large-scale condensation during the early forecast stage after insertion of satellite-observed temperature, water vapor, and cloud water formation. The assimilation of satellite-observed moisture and cloud water, together withy three-mode diabatic initialization, significantly alleviates the model precipitation spinup problem, especially in the first 3 h of the forecast. Experimental forecasts indicate that the impact of satellite-observed temperature and water vapor profiles and cloud water alone in the initialization procedure shortens the spinup time for precipitation rates by 1-2 h and for regeneration of the areal coverage by 3 h. The diabatic initialization further reduces the precipitation spinup time (compared to adiabatic initialization) by 1 h.

  18. Managing the Drivers of Air Flow and Water Vapor Transport in Existing Single-Family Homes

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, James [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States); Withers, Charles [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States); Martin, Eric [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States); Moyer, Neil [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States)

    2012-10-01

    This report is a revision of an earlier report titled: Measure Guideline: Managing the Drivers of Air Flow and Water Vapor Transport in Existing Single-Family Homes. Revisions include: Information in the text box on page 1 was revised to reflect the most accurate information regarding classifications as referenced in the 2012 International Residential Code. “Measure Guideline” was dropped from the title of the report. An addition was made to the reference list.

  19. Managing the Drivers of Air Flow and Water Vapor Transport in Existing Single Family Homes (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, J.; Withers, C.; Martin, E.; Moyer, N.

    2012-10-01

    This document focuses on managing the driving forces which move air and moisture across the building envelope. While other previously published Measure Guidelines focus on elimination of air pathways, the ultimate goal of this Measure Guideline is to manage drivers which cause air flow and water vapor transport across the building envelope (and also within the home), control air infiltration, keep relative humidity (RH) within acceptable limits, avoid combustion safety problems, improve occupant comfort, and reduce house energy use.

  20. The Influence of Summertime Convection Over Southeast Asia on Water Vapor in the Tropical Stratosphere

    Science.gov (United States)

    Wright, J. S.; Fu, R.; Fueglistaler, S.; Liu, Y. S.; Zhang, Y.

    2011-01-01

    The relative contributions of Southeast Asian convective source regions during boreal summer to water vapor in the tropical stratosphere are examined using Lagrangian trajectories. Convective sources are identified using global observations of infrared brightness temperature at high space and time resolution, and water vapor transport is simulated using advection-condensation. Trajectory simulations are driven by three different reanalysis data sets, GMAO MERRA, ERA-Interim, and NCEP/NCAR, to establish points of consistency and evaluate the sensitivity of the results to differences in the underlying meteorological fields. All ensembles indicate that Southeast Asia is a prominent boreal summer source of tropospheric air to the tropical stratosphere. Three convective source domains are identified within Southeast Asia: the Bay of Bengal and South Asian subcontinent (MON), the South China and Philippine Seas (SCS), and the Tibetan Plateau and South Slope of the Himalayas (TIB). Water vapor transport into the stratosphere from these three domains exhibits systematic differences that are related to differences in the bulk characteristics of transport. We find air emanating from SCS to be driest, from MON slightly moister, and from TIB moistest. Analysis of pathways shows that air detrained from convection over TIB is most likely to bypass the region of minimum absolute saturation mixing ratio over the equatorial western Pacific; however, the impact of this bypass mechanism on mean water vapor in the tropical stratosphere at 68 hPa is small 0.1 ppmv). This result contrasts with previously published hypotheses, and it highlights the challenge of properly quantifying fluxes of atmospheric humidity.

  1. The origin of water-vapor rings in tropical cold pools

    Science.gov (United States)

    Langhans, W.; Romps, D. M.

    2014-12-01

    An invigoration of deep convection by cold pools is supported by two conceptually different theories: a) mechanic lifting of air-parcels at the cold-pool boundary and b) thermodynamic preconditioning of boundary-layer air due to rings of enhanced water-vapor content (~ +1 g/kg). The latter have been associated with the leading edges of radially spreading cold pools in studies of precipitating convection over tropical oceans. Even recovered cold pools exhibit these moisture anomalies and the formation of such rings thus also plays a critical role in theory (a) through the moistening of ambient air that is later lifted by another cold-pool. Despite the described relevance, the origin of these water-vapor rings is unclear. This motivates us to conduct idealized large-eddy simulations with the purpose of explaining the origin of these water-vapor rings. The simulations are coupled with a recently designed framework to track Lagrangian water particles and allows us to decompose the emerging vapor distribution according to its origin. The emerging quasi-axisymmetric flow transitions from a vortex-dominated downdraft in the early stage to a radial gravity current in the later stage. Preliminary results highlight the dominating role of moisture that resides in the boundary layer before deep convection is initiated. A delineation of the individual contributions from boundary-layer moisture, evaporated hydrometeors, and latent heat fluxes reveals that the latter two sources may not be crucial for the anomalous moisture content over the radial distances considered. The sensitivity to the initial moisture of the boundary-layer and the effects of entrainment into the cold pool will be discussed.

  2. Water vapor mapping by fusing InSAR and GNSS remote sensing data and atmospheric simulations

    OpenAIRE

    Alshawaf, F.; Fersch, B.; Hinz, S; Kunstmann, H.; Mayer, M; Meyer, F.J.

    2015-01-01

    Data fusion aims at integrating multiple data sources that can be redundant or complementary to produce complete, accurate information of the parameter of interest. In this work, data fusion of precipitable water vapor (PWV) estimated from remote sensing observations and data from the Weather Research and Forecasting (WRF) modeling system is applied to provide complete, accurate grids of PWV. Our goal is to infer spatially continuous, prec...

  3. Inter-comparison of three commercial instruments for water vapor isotope measurement

    Science.gov (United States)

    Wen, X.; Sun, X.; Li, S.; Lee, X.

    2010-12-01

    The δ18O and δD of atmospheric water vapor provide rich information on the hydrological cycle and gaseous exchange processes between the terrestrial vegetation and the atmosphere. In the past, the majority of water vapor isotope studies have relied on discrete sampling using cold-trap/mass spectrometry methods. Recent development of isotope ratio infrared spectroscopy (IRIS) has made it possible to make in-situ, continuous observations of the δ18O and δD of atmospheric water vapor. In this paper, we report the results of an inter-comparison experiment using three commercial IRIS analyzers. These analyzers were developed on the basis of tunable diode laser absorption spectroscopy (model TGA100A, Campbell Scientific Inc., Logan, UT), off-axis integrated cavity output spectroscopy (model DLT-100, Los Gatos Research, Mountain View, CA) and wavelength-scanned cavity ring-down spectroscopy (models L1115-i and L1102-i, Picarro Inc., Sunnyvale, CA). Each analyzer was calibrated, at factory recommended frequencies, with its own calibration device traceable to the same working standard. The experiment consisted of two parts each lasting 2 weeks. First, the δ18O and δD of ambient water vapor from a common intake were measured simultaneously with these analyzers. The data reported for hourly intervals were analyzed to reveal how well these analyzers track natural variability in ambient conditions. Second, a home-made bubbler combined with dry air was used for performance evaluation under controlled conditions. The bubbler produced a moisture stream that followed the Rayleigh prediction, and with appropriate mixing with dry air provided a sufficient range of humidity at preset levels of mixing ratio (30,000, 20,000, 10,000, 5,000 ppm). Analysis of the experimental data is underway to (1) evaluate the relative precision and accuracy among these analyzers, (2) compare the measured isotopic ratios against the Rayleigh prediction, and (3) identify appropriate calibration

  4. Thin cuprous oxide films prepared by thermal oxidation of copper foils with water vapor

    Energy Technology Data Exchange (ETDEWEB)

    Liang Jianbo, E-mail: liangjienbo1980@yahoo.co.jp [Department of Frontier Materials,Nagoya Institute of Technology, Nagoya 4668555 (Japan); Kishi, Naoki; Soga, Tetsuo [Department of Frontier Materials,Nagoya Institute of Technology, Nagoya 4668555 (Japan); Jimbo, Takashi [Research Center for Nano-Device and System, Nagoya Institute of Technology, Nagoya 4668555 (Japan); Ahmed, Mohsin [Department of Frontier Materials,Nagoya Institute of Technology, Nagoya 4668555 (Japan)

    2012-01-31

    We present an improved preparation method for the growth of high quality crystals of cuprous oxide films grown by thermal oxidation of cupper foils with water vapor. This method proved to be good for preparing cuprous oxide films with high purity and large grain size. X-ray diffraction studies revealed the formation of Cu{sub 2}O films with preferred (111) orientation. The cuprous oxide diodes fabricated by the above technique have been studied using current-voltage method.

  5. THE THEORETICAL CRITERIA ON THE VAPORIZATION AND COMBUSTION RATES OF EMULSIONS WATER IN HEAVY FUEL OIL

    Directory of Open Access Journals (Sweden)

    Corneliu MOROIANU

    2012-05-01

    Full Text Available The vaporization and combustion characteristics of a heavy oil-water emulsion droplet are investigated with graphological method. The combustion graphology of fuel oils is defined as a new technical and scientific field which deals with the graphic transposition of the processes of fuels combustion development in a simulator. Thus, it is easy to establish the ignition-combustion characteristics, including the laws that govern their changes depending on the combustion conditions and fuel specifications

  6. Water vapor flow and high thermal resistance insulation systems for metal buildings

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, R.M.

    1983-01-01

    In response to increasing energy costs, high thermal resistance insulation systems are being marketed for pre-engineered metal buildings. Historically, blanket insulation has been installed between the skin and the structure of these buildings. The new insulation systems generally are installed inside the structure; thus the structure is colder and, unless an effective retarder is included, water vapor condensation problems can result. While the vapor permeance of various insulation facing materials is documented, the effect of such field conditions as seams and penetrations is less well known. Permeance tests were performed on samples of foil-kraft paper insulation facing with two seams and two penetration configurations. The tests show that seams can multiply the permeance of the vapor retarder by factors of 1.2 or more and penetrations can multiply the permeance by 3 or more. The theory of vapor flow analysis is reviewed and compared with the test results and presented graphically. Possible applications and suggestions for further investigation are discussed.

  7. Water vapor flow and high thermal resistance insulation systems for metal buildings

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, R.M.

    1981-12-01

    In response to increasing energy costs, high thermal resistance insulation systems are being marketed for pre-engineered metal buildings. Historically, blanket insulation has been installed between the skin and the structure of these buildings. The new insulation systems generally are installed inside the structure; thus the structure is colder and, unless an effective retarder is included, water vapor condensation problems can result. While the vapor permeance of various insulation facing materials is documented, the effect of such field conditions as seams and penetrations is less well known. Permeance tests were performed on samples of foil-kraft paper insulation facing with two seams and two penetration configurations. The tests show that seams can multiply the permeance of the vapor retarder by factors of 1.2 or more and penetrations can multiply the permeance by 3 or more. The theory of vapor flow analysis is reviewed and compared with the test results and presented graphically. Possible applications and suggestions for further investigation are discussed.

  8. On the Electronic Nature of the Surface Potential at the Vapor-Liquid Interface of Water

    Energy Technology Data Exchange (ETDEWEB)

    Kathmann, S M; Kuo, I; Mundy, C J

    2008-02-05

    The surface potential at the vapor-liquid interface of water is relevant to many areas of chemical physics. Measurement of the surface potential has been experimentally attempted many times, yet there has been little agreement as to its magnitude and sign (-1.1 to +0.5 mV). We present the first computation of the surface potential of water using ab initio molecular dynamics. We find that the surface potential {chi} = -18 mV with a maximum interfacial electric field = 8.9 x 10{sup 7} V/m. A comparison is made between our quantum mechanical results and those from previous molecular simulations. We find that explicit treatment of the electronic density makes a dramatic contribution to the electric properties of the vapor-liquid interface of water. The E-field can alter interfacial reactivity and transport while the surface potential can be used to determine the 'chemical' contribution to the real and electrochemical potentials for ionic transport through the vapor-liquid interface.

  9. Compact Reconnaissance Imaging Spectrometer Observations of Water Vapor and Carbon Monoxide

    Science.gov (United States)

    Smith, Michael D.; Wolff, Michael J.; Clancy, R. Todd; Murchie, Scott L.

    2009-01-01

    The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter (MRO) spacecraft began taking observations in September 2006 and has now collected more than a full Martian year of data. Retrievals performed using the near-infrared spectra obtained by CRISM are used to characterize the seasonal and spatial variation of the column abundance of water vapor and the column-averaged mixing ratio of carbon monoxide. CRISM retrievals show nominal behavior in water vapor during northern hemisphere spring and summer with maximum abundance reaching 50 precipitable micrometers. Water vapor abundance during the southern hemisphere spring and summer appears significantly reduced compared to observations by other instruments taken during previous years. The CRISM retrievals show the seasonally and globally averaged carbon monoxide mixing ratio to be 700 ppm, but with strong seasonal variations at high latitudes. The summertime near-polar carbon monoxide mixing ratio falls to 200 ppm in the south and 400 ppm in the north as carbon dioxide sublimates from the seasonal polar ice caps and dilutes noncondensable species including carbon monoxide. At low latitudes, the carbon monoxide mixing ratio varies in response to the mean seasonal cycle of surface pressure.

  10. Evaluation of tropospheric water vapor profiling using eye-safe, infrared differential absorption lidar

    Energy Technology Data Exchange (ETDEWEB)

    Rye, B.J. [Colorado Univ., Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences]|[National Oceanic and Atmospheric Administration, Boulder, CO (United States). Environmental Technology Lab.; Machol, J.L.; Grund, C.J.; Hardesty, R.M. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Environmental Technology Lab.

    1996-05-14

    Continuous, high quality profiles of water vapor, free of systematic bias, and of moderate temporal and spatial resolution are fundamental to the success of the ARM CART program. In addition, these should be acquired over long periods at low operational and maintenance cost. The development and verification of realistic climate model parameterizations for clouds and net radiation balance, and the correction of other CART site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. To date, application of profiles have been limited by vertical resolution and uniqueness and high operating cost, or diminished daytime performance, lack of eye-safety, and high maintenance cost. Recent developments in infrared laser and detector technology make possible compact IR differential absorption lidar (DIAL) systems at eye-safe wavelengths. In the studies reported here, we develop DIAL system performance models and examine the potential of solving some of the shortcomings of previous methods using parameters representative of current technologies. These simulations are also applied to determine the strengths and weaknesses unique to the DIAL method for this application.

  11. Water vapor transport in the lower mesosphere of the subtropics: a trajectory analysis

    Science.gov (United States)

    Flury, T.; Müller, S. C.; Hocke, K.; Kämpfer, N.

    2008-07-01

    The Institute of Applied Physics operates an airborne microwave radiometer that measures the rotational transition line of water vapor at 183.3 GHz. Measurements were acquired on board a Learjet once a year in the period 1998 to 2006. Water vapor profiles are retrieved for the altitude range from 15 to 75 km along the flight track. We report on a water vapor enhancement in the lower mesosphere above India and the Arabic Sea measured on our flight mission in November 2005 conducted during EC-project SCOUT-O3. The flight led from Switzerland to Australia and back. We find an enhancement of up to 25% in the lower mesospheric H2O volume mixing ratio measured on the return flight one week after the outward flight. The origin of the air is traced back by means of a trajectory model in the lower mesosphere. During the outward flight the air came from the Carribean and crossed the Atlantic Ocean. On the return flight the air came from China and orginated from mid latitudes. Thus the large variability of H2O VMR during our flight is explained by a change of the winds in the lower mesosphere.

  12. Enhancing our Understanding of the Arctic Atmospheric Hydrological Cycle using Observations from an International Arctic Water Vapor Isotope Network

    Science.gov (United States)

    Masson-Delmotte, V.; Steen-Larsen, H. C.; Werner, M.

    2014-12-01

    Due to the role of water vapor and clouds in positive feedback mechanisms, water vapor is a key player in the future of Arctic climate. Ecosystems and human societies are vulnerable to climate change through even minor changes in precipitation patterns, including the occurrence of extreme events. It is therefore essential to monitor, understand and model correctly the mechanisms of transport of moisture, at the regional scale. Water isotopes - the relative abundance of heavy and light water in the atmosphere - hold the key to understanding the physical processes influencing future Arctic climate. Water isotope observations in the atmosphere are a modern analog to the Rosetta Stone for understanding the processes involved in evaporation, moisture transport, cloud formation and to track moisture origin. Indeed, technological progress now allows continuous, in situ or remote sensing monitoring of water isotopic composition. In parallel, a growing number of atmospheric circulation models are equipped with the explicit modeling of water stable isotopes, allowing evaluation at the process scale. We present here data obtained through national or bi-national initiatives from stations onboard an icebreaker and land based stations in Greenland, Iceland, Svalbard, and Siberia - together forming an emerging international Arctic water vapor isotope network. Using water tagging and back trajectories we show water vapor of Arctic origin to have a high d-excess fingerprint. This show the potential of using water vapor isotopes as tracer for changes in the Arctic hydrological cycle. Using the network of monitoring stations we quantify using the isotopes advection of air masses and the key processes affecting the water vapor en-route between stations. We have successfully used the obtained atmospheric water vapor isotope observations to benchmark isotope-enabled general circulation models. This comparison allows us to address key processes of the atmospheric hydrological cycle for

  13. Isotopic equilibrium between precipitation and water vapor: evidence from continental rains in central Kenya

    Science.gov (United States)

    Soderberg, K.; Gerlein, C.; Kemeny, P. C.; Caylor, K. K.

    2013-12-01

    An accurate understanding of the relationships between the isotopic composition of liquid water and that of water vapor in the environment can help describe hydrologic processes across many scales. One such relationship is the isotopic equilibrium between falling raindrops and the surrounding vapor. The degree of equilibration is used to model the isotopic composition of precipitation in isotope-enable general circulation models and land-atmosphere exchange models. Although this equilibrium has been a topic of isotope hydrology research for more than four decades, few studies have included vapor measurements to validate modeling efforts. Recent advances in laser technology have allowed for in situ vapor measurements at high temporal resolution (e.g., >1 Hz). Here we present concomitant rain and vapor measurements for a series of 17 rain events during the 'Continental' rainy season (June through August) at Mpala Research Center in central Kenya. Rain samples (n=218) were collected at intervals of 2 to 35 minutes (median of 3 minutes) depending on the rain rate (0.4 to 10.5 mm/hr). The volume-weighted mean rain values for δ18O, δ2H and D-excess (δ2H - 8* δ18O) were 0.1 ‰, 10.7 ‰, and 10.1 ‰. These values are more enriched than the annual weighted means reported for the area (-2.2 ‰, -7.6 ‰, and 11.0 ‰, respectively). Vapor was measured continuously at ~2Hz (DLT-100, Los Gatos Research), with an inverted funnel intake 4m above the ground surface. The mean vapor isotopic composition during the rain events was -10.0 +/- 1.2 ‰ (1 σ) for δ18O and -73.9 +/- 7.0 ‰ for δ2H. The difference between the rain sample isotopic composition and that of liquid in isotopic equilibrium with the corresponding vapor at the ambient temperature was 0.8 +/- 2.2 ‰ for δ18O and 6.2 +/- 7.0 ‰ for δ2H. This disequilibrium was found to correlate with the natural log of rain rate (R2 of 0.26 for δ18O and 0.46 for δ2H), with lower rain rates having larger

  14. Desalination of water by vapor-phase transport through hydrophobic nanopores

    Science.gov (United States)

    Lee, Jongho; Karnik, Rohit

    2010-08-01

    We propose a new approach to desalination of water whereby a pressure difference across a vapor-trapping nanopore induces selective transport of water by isothermal evaporation and condensation across the pore. Transport of water through a nanopore with saline water on one side and pure water on the other side under a pressure difference was theoretically analyzed under the rarefied gas assumption using a probabilistic framework that accounts for diffuse scattering from the pore walls as well as reflection from the menisci. The analysis revealed that in addition to salinity, temperature, and pressure difference, the nanopore aspect ratio and the probability of condensation of a water molecule incident on a meniscus from the vapor phase, known as the condensation coefficient, are key determinants of flux. The effect of condensation coefficient on mass flux becomes critical when the aspect ratio is small. However, the mass flux becomes independent of the condensation coefficient as the pore aspect ratio increases, converging to the Knudsen flux for long nanopores. For design of a nanopore membrane that can trap vapor, a minimum aspect ratio is derived for which coalescence of the two interfaces on either side of the nanopore remains energetically unfavorable. Based on this design criterion, the analysis suggests that mass flux in the range of 20-70 g/m2 s may be feasible if the system is operated at temperatures in the range of 30-50 °C. The proposed approach further decouples transport properties from material properties of the membrane, which opens the possibility of engineering membranes with appropriate materials that may lead to reverse osmosis membranes with improved flux, better selectivity, and high chlorine resistance.

  15. Tracking atmospheric boundary layer dynamics with water vapor D-excess observations

    KAUST Repository

    Parkes, Stephen

    2015-04-01

    Stable isotope water vapor observations present a history of hydrological processes that have impacted on an air mass. Consequently, there is scope to improve our knowledge of how different processes impact on humidity budgets by determining the isotopic end members of these processes and combining them with in-situ water vapor measurements. These in-situ datasets are still rare and cover a limited geographical expanse, so expanding the available data can improve our ability to define isotopic end members and knowledge about atmospheric humidity dynamics. Using data collected from an intensive field campaign across a semi-arid grassland site in eastern Australia, we combine multiple methods including in-situ stable isotope observations to study humidity dynamics associated with the growth and decay of the atmospheric boundary layer and the stable nocturnal boundary layer. The deuterium-excess (D-excess) in water vapor is traditionally thought to reflect the sea surface temperature and relative humidity at the point of evaporation over the oceans. However, a number of recent studies suggest that land-atmosphere interactions are also important in setting the D-excess of water vapor. These studies have shown a highly robust diurnal cycle for the D-excess over a range of sites that could be exploited to better understand variations in atmospheric humidity associated with boundary layer dynamics. In this study we use surface radon concentrations as a tracer of surface layer dynamics and combine these with the D-excess observations. The radon concentrations showed an overall trend that was inversely proportional to the D-excess, with early morning entrainment of air from the residual layer of the previous day both diluting the radon concentration and increasing the D-excess, followed by accumulation of radon at the surface and a decrease in the D-excess as the stable nocturnal layer developed in the late afternoon and early evening. The stable nocturnal boundary layer

  16. Precipitable water vapor characterization in the coastal regions of China based on ground-based GPS

    Science.gov (United States)

    Wang, Zhaoyang; Zhou, Xinghua; Liu, Yanxiong; Zhou, Dongxu; Zhang, Huayi; Sun, Weikang

    2017-12-01

    Water vapor plays an important role in climate change; thus, studying the spatial distribution and temporal variation of precipitable water vapor (PWV) in the coastal regions of China would help researchers to understand the climate characteristics of those regions. In this paper, 6-year 1-h interval PWV were derived from 27 Global Positioning System stations observations of Chinese coastal GPS observation network, surface meteorological data and European Center for Medium-Range Weather Forecasts (ERA-Interim) reanalysis products. The present study provides the use of these data to investigate the spatial-temporal variability of water vapor throughout the coastal regions of China. Latitude is the main factor affecting the spatial distribution of GPS-derived PWV; that is, PWV decreased by about 1.5 mm for each 1° increase of latitude. For regions at the same latitude, a region that is relatively close to the ocean will have a higher content of PWV. The PWV in the southeastern and southwestern coastal regions of China is significantly higher in summer; this may be influenced by the southeastern and southwestern water vapor inflow corridors. The PWV obviously varies monthly, reaching a minimum in January; however, the timing of the maximum varied but usually appeared in June, July or August and was affected by the monsoons. The PWV varies largely between summer and winter with a larger gradient of change in PWV with latitude in winter than in summer. The positive correlation coefficient between PWV and the surface temperature varied in different seasons; this is related to the changes of temperature and the horizontal motion of water vapor. Use of the Fast Fourier Transform method showed that the PWV time series data have multi-scale characteristics. The amplitude and phase of the PWV time series in annual, semiannual, four month and seasonal cycles were extracted through harmonic wave analysis. The amplitude of four month and seasonal cycles did not pass

  17. GOZCARDS Source Data for Water Vapor Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOZCARDS Source Data for Water Vapor Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozSmlpH2O) contains zonal means and related...

  18. SPARC-IGAC Symposium on Climate-Chemistry Interactions. Climate Feedback by Water Vapor in the Tropical Upper Troposphere

    Science.gov (United States)

    Dessler, A. E.; Minschwaner, K.

    2003-01-01

    The strong greenhouse forcing by atmospheric water vapor is expected to play an important role in shaping the direction of any future changes in climate. We present calculations that provide a new perspective on the sensitivity of upper tropospheric water vapor to changes in surface temperature. Equilibrium states of our atmospheric model show unambiguously that as the surface warms, changes in the vertical distribution and temperature of detraining air parcels from tropical convection lead to higher water vapor mixing ratios in the upper troposphere. However, the increase in mixing ratio is not as large as the increase in saturation mixing ratio due to warmer environmental temperatures, so that the relative humidity decreases. Our analysis suggests that models that maintain a fixed relative humidity are likely overestimating the magnitude of the water vapor feedback.

  19. GOZCARDS Merged Data for Water Vapor Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOZCARDS Merged Data for Water Vapor Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozMmlpH2O) contains zonal means and related...

  20. Continuous Water Vapor Mass Flux and Temperature Measurements in a Model Scramjet Combustor Using a Diode Laser Sensor

    National Research Council Canada - National Science Library

    Upschulte, B. L; Miller, M. F; Allen, M. G; Jackson, K; Gruber, M; Mathur, T

    1998-01-01

    A sensor for simultaneous measurements of water vapor density, temperature and velocity has been developed based on absorption techniques using room temperature diode lasers (InGaAsP) operating at 1.31 micrometers...

  1. MODIS/Terra Near Real Time (NRT) Temperature and Water Vapor Profiles 5-Min L2 Swath 5km

    Data.gov (United States)

    National Aeronautics and Space Administration — The level-2 MODIS Temperature and Water Vapor Profile Product MOD07_L2 consists of 30 gridded parameters related to atmospheric stability, atmospheric temperature...

  2. MODIS/Terra Total Precipitable Water Vapor 5-Min L2 Swath 1km and 5km V006

    Data.gov (United States)

    National Aeronautics and Space Administration — This Level 2 data collection contains derived precipitable column water vapor amounts, during daytime using a near-infrared over clear land areas and above clouds...

  3. MODIS/Aqua Near Real Time (NRT) Temperature and Water Vapor Profiles 5-Min L2 Swath 5km

    Data.gov (United States)

    National Aeronautics and Space Administration — The level-2 MODIS Temperature and Water Vapor Profile Product MYD07_L2 consists of 30 gridded parameters related to atmospheric stability, atmospheric temperature...

  4. MODIS/Aqua Total Precipitable Water Vapor 5-Min L2 Swath 1km and 5km V005 NRT

    Data.gov (United States)

    National Aeronautics and Space Administration — This Level 2 data collection contains derived precipitable column water vapor amounts, during daytime using a near-infrared over clear land areas and above clouds...

  5. MODIS/Terra Total Precipitable Water Vapor 5-Min L2 Swath 1km and 5km V005 NRT

    Data.gov (United States)

    National Aeronautics and Space Administration — This Level 2 data collection contains derived precipitable column water vapor amounts, during daytime using a near-infrared over clear land areas and above clouds...

  6. A feasibility study of a microwave water vapor measurement from a space probe along an occultation path

    Science.gov (United States)

    Longbothum, R. L.

    1975-01-01

    Stratospheric and mesospheric water vapor measurements were taken using the microwave lines at 22 GHz (22.235 GHz) and 183 GHz (183.31 GHz). The resonant cross sections for both the 22 GHz and the 183 GHz lines were used to model the optical depth of atmospheric water vapor. The range of optical depths seen by a microwave radiometer through the earth's limb was determined from radiative transfer theory. Radiometer sensitivity, derived from signal theory, was compared with calculated optical depths to determine the maximum height to which water vapor can be measured using the following methods: passive emission, passive absorption, and active absorption. It was concluded that measurements using the 22 GHz line are limited to about 50 km whereas the 183 GHz line enables measurements up to and above 100 km for water vapor mixing ratios as low as 0.1 ppm under optimum conditions.

  7. Vapor-Liquid Equilibrium of Methane with Water and Methanol. Measurements and Modeling

    DEFF Research Database (Denmark)

    Frost, Michael Grynnerup; Karakatsani, Eirini; von Solms, Nicolas

    2014-01-01

    There is a need for high-quality experimental phase equilibrium data in the petroleum and chemical industries, for example, mixtures of oil and gas with gas hydrate inhibitors (methanol, glycols) and organic acids. This includes a wide range of different systems, which all deal with processes...... that rely on phase equilibrium data for optimization. The objective of this work is to provide experimental data for hydrocarbon systems with polar chemicals such as alcohols, glycols, and water. New vapor-liquid equilibrium data are reported for methane + water, methane + methanol, and methane + methanol...

  8. Evaluation of Water Vapor Sorption Hysteresis in Soils: The Role of Organic Matter and Clay

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

    2015-01-01

    Hysteresis of the soil water characteristic (SWC) has been extensively studied for matric potentials between zero and −1.5 MPa. However, little information is available on how to quantify, evaluate, and identify the causes of hysteresis at potentials below −10 MPa where vapor sorption plays...... an important role. It is clear that modeling physical and biological soil processes is more accurate when SWC hysteresis is considered, particularly at low potentials where small differences in water content are associated with large changes in potential energy. The objectives of the presented study were to...

  9. Electrical characteristics and hydrogen concentration of chemical vapor deposited silicon dioxide films: Effect of water treatment

    Science.gov (United States)

    Li, S. C.; Murarka, S. P.

    1992-11-01

    The effect of exposing chemical vapor deposited silicon dioxide directly to water has been investigated. Unlike the effect of the water-related traps in thermally grown silicon dioxide, the capacitance-voltage (C-V) shift due to diffused-in water molecules is directly observed without using the method of avalanche injection. The resonate nuclear reaction technique with 15N ion beam has been used to measure the hydrogen concentration of water-boiled, as-deposited, and rapid thermal-annealed silicon dioxide films. These depth profiles show that the hydrogen-containing species, that are most likely water molecules, diffuse in and out and redistribute in the as-deposited and rapid thermal-annealed films. These hydrogen depth profiles also indicate that the amount of diffused-in water molecules in the oxide is limited by the solubility of the water in the oxide. The solubility of water in the oxide annealed at high temperatures is found to be significantly lower than that in the as-deposited oxide. It is found that diffused-in water molecules, in order to satisfy the water solubility of the oxide, play a compensating role in controlling the oxide charges. Water molecules would continue to diffuse in, and interact with oxide charges and produce charges with reverse polarity that compensate the existing oxide charges until water solubility is satisfied.

  10. Heat and Mass Diffusions in the Absorption of Water Vapor by Aqueous Solution of Lithium Bromide

    Science.gov (United States)

    Kashiwagi, Takao; Kurosaki, Yasuo; Nikai, Isao

    The recent development of absorption-type heat pump is highly essential from the viewpoint of extracting the effective energy from waste heat or solar energy. To increase the efficiency of energy conversion, it is important to improve the performance of absorbers. The objective of this paper is to obtain an increased understanding of the fine mechanisms of vapor absorption. A system combining holographic interferometry wity thermometry is adopted to observe the progress of one-dimensional water vapor absorption by aqueous solution of lithium bromide (LiBr) and also to measure the unsteady temperature and concentration distributions in the absorption process. The experiments are carried out under the condition that the solution surface is exposed to the saturated water vapor at reduced pressure, and the effects of LiBr mass concentration on absorption mechanism are examined in the concentration range 20-60 mass%. The interference fringes are analyzed to distinguish between the layers of heat conduction and mass diffusion. The temperature and concentration distributions thus determined experimentally are compared with numerical solutions obtained by the equations for unsteady heat conduction and mass diffusion taking into consideration the effect of heat by dilution, to give reasonable values of mass diffusivity hitherto remaining unknown. Especially in the range of 40-60 mass%, the mass diffusivity decreases extremely with the increase of mass concentration of LiBr and it falls down to 0.7-0.8×10-9 m2/s in case of 60 mass% solution.

  11. Antarctic measurements of ozone, water vapor, and aerosol extinction by Sage 2 in the spring of 1987

    Science.gov (United States)

    Larsen, J. C.; Mccormick, M. Patrick

    1988-01-01

    Recent measurements of ozone, water vapor, and aerosol extinction from the spring of 1987 are presented and compared to 1985 and 1986. The observed changes to variations in meteorological conditions in the vortex for these three years are noted. March ozone data at similar latitudes for these three years will be used to investigate coupling between severity of the springtime depletion and early fall values. Researchers also investigate correlations between the measured species of water vapor, ozone, and aerosols throughout the vortex region.

  12. Performance of a Cross-Flow Humidifier with a High Flux Water Vapor Transport Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, R. K.; Wang, X.; Johnson, W. B.; Berg, F.; Kadylak, D.

    2015-09-30

    Water vapor transport (WVT) flux across a composite membrane that consists of a very thin perfluorosulfonic acid (PFSA) ionomer layer sandwiched between two expanded polytetrafluoroethylene (PTFE) microporous layers is investigated. Static and dynamic tests are conducted to measure WVT flux for different composite structures; a transport model shows that the underlying individual resistances for water diffusion in the gas phase and microporous and ionomer layers and for interfacial kinetics of water uptake at the ionomer surface are equally important under different conditions. A finite-difference model is formulated to determine water transport in a full-scale (2-m2 active membrane area) planar cross-flow humidifier module assembled using pleats of the optimized composite membrane. In agreement with the experimental data, the modeled WVT flux in the module increases at higher inlet relative humidity (RH) of the wet stream and at lower pressures, but the mass transfer effectiveness is higher at higher pressures. The model indicates that the WVT flux is highest under conditions that maintain the wet stream at close to 100% RH while preventing the dry stream from becoming saturated. The overall water transport is determined by the gradient in RH of the wet and dry streams but is also affected by vapor diffusion in the gas layer and the microporous layer.

  13. Observations of water vapor by ground-based micro-wave radiometers and Raman lidar

    Science.gov (United States)

    Han, Yong; Snider, J. B.; Westwater, E. R.; Melfi, S. H.; Ferrare, R. A.

    1994-09-01

    In November to December 1991, a substantial number of remote sensors and in situ instruments were operated together in Coffeyville, Kansas, during the climate experiment FIRE II. Included in the suite of instruments were (1) the NOAA Environmental Technology Laboratory (ETL) three-channel microwave radiometer, (2) the NASA GSFC Raman lidar, (3) ETL radio acoustic sounding system (RASS), and (4) frequent, research-quality radiosondes. The Raman lidar operated only at night and the focus of this portion of the experiment concentrated on clear conditions. The lidar data, together with frequent radiosondes and measurements of temperature profiles (every 15 min) by RASS allowed profiles of temperature and absolute humidity to be estimated every minute. We compared 2-min measurements of brightness temperature (Tb) with calculations of Tb that were based on the Liebe and Lay ton (1987) and Liebe et al. (1993) microwave propagation models, as well as the Waters (1976) model. The comparisons showed the best agreement at 20.6 GHz with the Waters model, with the Liebe et al. (1993) model being best at 31.65 GHz. The results at 90 GHz gave about equal success with the Liebe and Layton (1987) and Liebe et al. (1993) models. Comparisons of precipitable water vapor derived independently from the two instruments also showed excellent agreement, even for averages as short as 2 min. The rms difference between Raman and radiometric determinations of precipitable water vapor was 0.03 cm which is roughly 2%. The experiments clearly demonstrate the potential of simultaneous operation of radiometers and Raman lidars for fundamental physical studies of water vapor.

  14. Formation of microbeads during vapor explosions of Field's metal in water

    KAUST Repository

    Kouraytem, Nadia

    2016-06-17

    We use high-speed video imaging to investigate vapor explosions during the impact of a molten Field\\'s metal drop onto a pool of water. These explosions occur for temperatures above the Leidenfrost temperature and are observed to occur in up to three stages as the metal temperature is increased, with each explosion being more powerful that the preceding one. The Field\\'s metal drop breaks up into numerous microbeads with an exponential size distribution, in contrast to tin droplets where the vapor explosion deforms the metal to form porous solid structures. We compare the characteristic bead size to the wavelength of the fastest growing mode of the Rayleigh-Taylor instability.

  15. Water vapor increase in the northern hemispheric lower stratosphere by the Asian monsoon anticyclone observed during TACTS campaign in 2012

    Science.gov (United States)

    Rolf, Christian; Vogel, Bärbel; Hoor, Peter; Günther, Gebhard; Krämer, Martina; Müller, Rolf; Müller, Stephan; Riese, Martin

    2017-04-01

    Water vapor plays a key role in determining the radiative balance in the upper troposphere and lower stratosphere (UTLS) and thus the climate of the Earth (Forster and Shine, 2002; Riese et al., 2012). Therefore a detailed knowledge about transport pathways and exchange processes between troposphere and stratosphere is required to understand the variability of water vapor in this region. The Asian monsoon anticyclone caused by deep convection over and India and east Asia is able to transport air masses from the troposphere into the nothern extra-tropical stratosphere (Müller et al. 2016, Vogel et al. 2016). These air masses contain pollution but also higher amounts of water vapor. An increase in water vapor of about 0.5 ppmv in the extra-tropical stratosphere above a potential temperature of 380 K was detected between August and September 2012 by in-situ instrumentation above the European northern hemisphere during the HALO aircraft mission TACTS. Here, we investigated the origin of this water vapor increase with the help of the 3D Lagrangian chemistry transport model CLaMS (McKenna et al., 2002). We can assign an origin of the moist air masses in the Asian region (North and South India and East China) with the help of model origin tracers. Additionally, back trajectories of these air masses with enriched water vapor are used to differentiate between transport from the Asia monsoon anticyclone and the upwelling of moister air in the tropics particularly from the Pacific and Southeast Asia.

  16. Cirrus and water vapor transport in the tropical tropopause layer – Part 1: A specific case modeling study

    Directory of Open Access Journals (Sweden)

    T. Dinh

    2012-10-01

    Full Text Available In a simulation of a tropical-tropopause-layer (TTL cirrus forced by a large-scale equatorial Kelvin wave, the radiatively induced mesoscale dynamics of the cloud actively contributes to the transport of water vapor in the vertical direction.

    In a typical TTL cirrus, the heating that results from absorption of radiation by ice crystals induces a mesoscale circulation. Advection of water vapor by the radiatively induced circulation leads to upward advection of the cloudy air. Upward advection of the cloudy air is equivalent to upward transport of water vapor when the air above the cloud is drier than the cloudy air. On the other hand, ice nucleation and depositional growth, followed by sedimentation and sublimation lead to downward transport of water vapor.

    Under the conditions specific to our simulation, the upward transport of water vapor by the mesoscale circulation dominates the downward transport by microphysical processes. The net result is upward transport of water vapor, which is equivalent to hydration of the lower stratosphere. Sensitivity to model conditions and parameters will be discussed in a follow-up paper.

  17. Treatment of Produced Waters Using a Surfactant Modified Zeolite/Vapor Phase Bioreactor System

    Energy Technology Data Exchange (ETDEWEB)

    Lynn E. Katz; Kerry A. Kinney; R. S. Bowman; E. J. Sullivan

    2004-03-11

    This report summarizes work of this project from October 2003 through March 2004. The major focus of the research was to further investigate BTEX removal from produced water, to quantify metal ion removal from produced water, and to evaluate a lab-scale vapor phase bioreactor (VPB) for BTEX destruction in off-gases produced during SMZ regeneration. Batch equilibrium sorption studies were conducted to evaluate the effect of semi-volatile organic compounds commonly found in produced water on the sorption of benzene, toluene, ethylbenzene, and xylene (BTEX) onto surfactant-modified zeolite (SMZ) and to examine selected metal ion sorption onto SMZ. The sorption of polar semi-volatile organic compounds and metals commonly found in produced water onto SMZ was also investigated. Batch experiments were performed in a synthetic saline solution that mimicked water from a produced water collection facility in Wyoming. Results indicated that increasing concentrations of semi-volatile organic compounds increased BTEX sorption. The sorption of phenol compounds could be described by linear isotherms, but the linear partitioning coefficients decreased with increasing pH, especially above the pKa's of the compounds. Linear correlations relating partitioning coefficients of phenol compounds with their respective solubilities and octanol-water partitioning coefficients were developed for data collected at pH 7.2. The sorption of chromate, selenate, and barium in synthetic produced water were also described by Langmuir isotherms. Experiments conducted with a lab-scale vapor phase bioreactor (VPB) packed with foam indicated that this system could achieve high BTEX removal efficiencies once the nutrient delivery system was optimized. The xylene isomers and benzene were found to require the greatest biofilter bed depth for removal. This result suggested that these VOCs would ultimately control the size of the biofilter required for the produced water application. The biofilter

  18. Experimental Validation of Hybrid Distillation-Vapor Permeation Process for Energy Efficient Ethanol-Water Separation

    Science.gov (United States)

    The energy demand of distillation-based systems for ethanol recovery and dehydration can be significant, particularly for dilute solutions. An alternative separation process integrating vapor stripping with a vapor compression step and a vapor permeation membrane separation step,...

  19. Environmental controls over carbon dioxide and water vapor exchange of terrestrial vegetation

    DEFF Research Database (Denmark)

    Law, B.E.; Falge, E.; Gu, L.

    2002-01-01

    compared with forests. Ecosystem respiration was weakly correlated with mean annual temperature across biomes, in spite of within site sensitivity over shorter temporal scales. Mean annual temperature and site water balance explained much of the variation in gross photosynthesis. Water availability limits......The objective of this research was to compare seasonal and annual estimates of CO2 and water vapor exchange across sites in forests, grasslands, crops, and tundra that are part of an international network called FLUXNET, and to investigating the responses of vegetation to environmental variables...... associated with reduced temperature. The slope of the relation between monthly gross ecosystem production and evapotranspiration was similar between biomes. except for tundra vegetation, showing a strong linkage between carbon gain and water loss integrated over the year (slopes = 3.4 g CO2/kg H2O...

  20. Fuel for cyclones: The water vapor budget of a hurricane as dependent on its movement

    Science.gov (United States)

    Makarieva, Anastassia M.; Gorshkov, Victor G.; Nefiodov, Andrei V.; Chikunov, Alexander V.; Sheil, Douglas; Nobre, Antonio Donato; Li, Bai-Lian

    2017-09-01

    Despite the dangers associated with tropical cyclones and their rainfall, the origin of the moisture in these storms, which include destructive hurricanes and typhoons, remains surprisingly uncertain. Existing studies have focused on the region 40-400 km from a cyclone's center. It is known that the rainfall within this area cannot be explained by local processes alone but requires imported moisture. Nonetheless, the dynamics of this imported moisture appears unknown. Here, considering a region up to three thousand kilometers from cyclone center, we analyze precipitation, atmospheric moisture and movement velocities for severe tropical cyclones - North Atlantic hurricanes. Our findings indicate that even over such large areas a hurricane's rainfall cannot be accounted for by concurrent evaporation. We propose instead that a hurricane consumes pre-existing atmospheric water vapor as it moves. The propagation velocity of the cyclone, i.e. the difference between its movement velocity and the mean velocity of the surrounding air (steering flow), determines the water vapor budget. Water vapor available to the hurricane through its movement makes the hurricane self-sufficient at about 700 km from the hurricane center obviating the need to concentrate moisture from greater distances. Such hurricanes leave a dry wake, whereby rainfall is suppressed by up to 40% compared to the local long-term mean. The inner radius of this dry footprint approximately coincides with the hurricane's radius of water self-sufficiency. We discuss how Carnot efficiency considerations do not constrain the power of such open systems. Our findings emphasize the incompletely understood role and importance of atmospheric moisture stocks and dynamics in the behavior of severe tropical cyclones.

  1. Effects of water vapor absorption on the physical and chemical stability of amorphous sodium indomethacin.

    Science.gov (United States)

    Tong, Ping; Zografi, George

    2004-03-12

    This study reports on the effects that water absorbed into amorphous sodium indomethacin (NaIMC) can have on simultaneous tendencies to crystallize to its trihydrate form and to undergo base-catalyzed hydrolysis because of the plasticizing effects of water on molecular mobility. Measurement of water vapor absorption at 30 degrees C and powder x-ray diffraction patterns as a function of relative humidity (RH) reveal that upon exposure to 21% RH, NaIMC does not crystallize over a 2-month period. Measurements of the glass transition temperature as a function of such exposure reveals a change in T(g) from 121 degrees C, dry, to 53 degrees C at 21% RH, such that T(g) at 21% RH is approximately 13 degrees C above the highest storage temperature of 40 degrees C used in the study. At 56% RH and higher, however, crystallization to the trihydrate occurs rapidly; although over the 2-month period, crystallization was never complete. Assessment of chemical degradation by high-performance liquid chromatography analysis revealed significant instability at 21% RH; whereas at higher RH, the extent of chemical degradation was reduced, reflecting the greater crystallization to the more chemically stable crystalline form. It is concluded that when amorphous forms of salts occur in solid dosage forms, the simultaneous effects of enhanced water vapor sorption on crystallization and chemical degradation must be considered, particularly when assessing solid-state chemical degradation at higher temperatures and RH (eg, 40 degrees C 75% RH).

  2. Water Vapor and its Isotopic Composition in the Upper Troposphere and Stratosphere

    Science.gov (United States)

    Dessler, A. E.; Sherwood, S. C.

    2003-01-01

    Any theory of water vapor in the tropical tropopause layer (TTL) must explain both the abundance and isotopic composition of water there. We have previously presented a model of the TTL that simulated the abundance of water vapor as well as the details of the vertical profile. That model included the effects of 'overshooting convection', which injects dry air directly into the TTL. Here, we present results for the model after modifying it to include water's stable isotope HDO. The model is capable of accurately simulating the recently observed, nearly uniform HDO depletion (delta D) in the TTL. We find that lofted ice is necessary to accurately simulate the profile of delta D in the TTL, as has been suggested previously. We also find that vertical mixing due to overshooting convection plays an important role in maintaining the observed profile. Finally, any theory of lofted ice requires a complementary source of dry air in the TTL; without that, the TTL will rapidly saturate and the lofted ice will not evaporate.

  3. Water injection into vapor- and liquid-dominated reservoirs: Modeling of heat transfer and mass transport

    Energy Technology Data Exchange (ETDEWEB)

    Pruess, K.; Oldenburg, C.; Moridis, G.; Finsterle, S. [Lawrence Berkeley National Lab., CA (United States)

    1997-12-31

    This paper summarizes recent advances in methods for simulating water and tracer injection, and presents illustrative applications to liquid- and vapor-dominated geothermal reservoirs. High-resolution simulations of water injection into heterogeneous, vertical fractures in superheated vapor zones were performed. Injected water was found to move in dendritic patterns, and to experience stronger lateral flow effects than predicted from homogeneous medium models. Higher-order differencing methods were applied to modeling water and tracer injection into liquid-dominated systems. Conventional upstream weighting techniques were shown to be adequate for predicting the migration of thermal fronts, while higher-order methods give far better accuracy for tracer transport. A new fluid property module for the TOUGH2 simulator is described which allows a more accurate description of geofluids, and includes mineral dissolution and precipitation effects with associated porosity and permeability change. Comparisons between numerical simulation predictions and data for laboratory and field injection experiments are summarized. Enhanced simulation capabilities include a new linear solver package for TOUGH2, and inverse modeling techniques for automatic history matching and optimization.

  4. Development of a quasi-adiabatic calorimeter for the determination of the water vapor pressure curve.

    Science.gov (United States)

    Mokdad, S; Georgin, E; Hermier, Y; Sparasci, F; Himbert, M

    2012-07-01

    Progress in the knowledge of the water saturation curve is required to improve the accuracy of the calibrations in humidity. In order to achieve this objective, the LNE-CETIAT and the LNE-CNAM have jointly built a facility dedicated to the measurement of the saturation vapor pressure and temperature of pure water. The principle is based on a static measurement of the pressure and the temperature of pure water in a closed, temperature-controlled thermostat, conceived like a quasi-adiabatic calorimeter. A copper cell containing pure water is placed inside a temperature-controlled copper shield, which is mounted in a vacuum-tight stainless steel vessel immersed in a thermostated bath. The temperature of the cell is measured with capsule-type standard platinum resistance thermometers, calibrated with uncertainties below the millikelvin. The vapor pressure is measured by calibrated pressure sensors connected to the cell through a pressure tube whose temperature is monitored at several points. The pressure gauges are installed in a thermostatic apparatus ensuring high stability of the pressure measurement and avoiding any condensation in the tubes. Thanks to the employment of several technical solutions, the thermal contribution to the overall uncertainty budget is reduced, and the remaining major part is mainly due to pressure measurements. This paper presents a full description of this facility and the preliminary results obtained for its characterization.

  5. Modeling of the Enceladus water vapor jets for interpreting UVIS star and solar occultation observations

    Science.gov (United States)

    Portyankina, Ganna; Esposito, Larry W.; Aye, Klaus-Michael; Hansen, Candice J.

    2015-11-01

    One of the most spectacular discoveries of the Cassini mission is jets emitting from the southern pole of Saturn’s moon Enceladus. The composition of the jets is water vapor and salty ice grains with traces of organic compounds. Jets, merging into a wide plume at a distance, are observed by multiple instruments on Cassini. Recent observations of the visible dust plume by the Cassini Imaging Science Subsystem (ISS) identified as many as 98 jet sources located along “tiger stripes” [Porco et al. 2014]. There is a recent controversy on the question if some of these jets are “optical illusion” caused by geometrical overlap of continuous source eruptions along the “tiger stripes” in the field of view of ISS [Spitale et al. 2015]. The Cassini’s Ultraviolet Imaging Spectrograph (UVIS) observed occultations of several stars and the Sun by the water vapor plume of Enceladus. During the solar occultation separate collimated gas jets were detected inside the background plume [Hansen et al., 2006 and 2011]. These observations directly provide data about water vapor column densities along the line of sight of the UVIS instrument and could help distinguish between the presence of only localized or also continuous sources. We use Monte Carlo simulations and Direct Simulation Monte Carlo (DSMC) to model the plume of Enceladus with multiple (or continuous) jet sources. The models account for molecular collisions, gravitational and Coriolis forces. The models result in the 3-D distribution of water vapor density and surface deposition patterns. Comparison between the simulation results and column densities derived from UVIS observations provide constraints on the physical characteristics of the plume and jets. The specific geometry of the UVIS observations helps to estimate the production rates and velocity distribution of the water molecules emitted by the individual jets.Hansen, C. J. et al., Science 311:1422-1425 (2006); Hansen, C. J. et al, GRL 38:L11202 (2011

  6. Energy and water vapor transport across a simplified cloud-clear air interface

    Science.gov (United States)

    Gallana, L.; Di Savino, S.; De Santi, F.; Iovieno, M.; Tordella, D.

    2014-11-01

    We consider a simplified physics of the could interface where condensation, evaporation and radiation are neglected and momentum, thermal energy and water vapor transport is represented in terms of the Boussinesq model coupled to a passive scalar transport equation for the vapor. The interface is modeled as a layer separating two isotropic turbulent regions with different kinetic energy and vapor concentration. In particular, we focus on the small scale part of the inertial range of the atmospheric boundary layer as well as on the dissipative range of scales which are important to the micro-physics of warm clouds. We have numerically investigated stably stratified interfaces by locally perturbing at an initial instant the standard temperature lapse rate at the cloud interface and then observing the temporal evolution of the system. When the buoyancy term becomes of the same order of the inertial one, we observe a spatial redistribution of the kinetic energy which produce a concomitant pit of kinetic energy within the mixing layer. In this situation, the mixing layer contains two interfacial regions with opposite kinetic energy gradient, which in turn produces two intermittent sublayers in the velocity fluctuations field. This changes the structure of the field with respect to the corresponding non-stratified shearless mixing: the communication between the two turbulent region is weak, and the growth of the mixing layer stops. These results are discussed with respect to Large Eddy Simulations data for the Planetary Boundary Layers.

  7. Interaction enthalpies of solid human serum albumin with water-dioxane mixtures: comparison with water and organic solvent vapor sorption

    Energy Technology Data Exchange (ETDEWEB)

    Sirotkin, Vladimir A.; Faizullin, Djihanguir A

    2004-06-07

    Enthalpy changes ({delta}H{sub tot}) on the immersion of dehydrated human serum albumin (HSA) into water-dioxane mixtures have been measured using a Setaram BT-2.15 calorimeter at 298 K. Thermodynamic activity of water was varied from 0 to 1. Calorimetric results are discussed together with the FTIR-spectroscopic data on water and organic solvent vapor adsorption/desorption isotherms on solid HSA. Dioxane sorption exhibits a pronounced hysteresis. Calorimetric and dioxane desorption dependencies consist of two parts. No dioxane sorption was observed in low water activity region (a{sub w}<0.5). At low water activities, the {delta}H{sub tot} values are close to zero. At water activity about 0.5 the sharp exothermic drop of the interaction enthalpy values was observed. This exothermic drop is accompanied by the sharp increase in the amount of sorbed dioxane and additional water sorption (compared with that for pure water). Dioxane adsorption branch resembles a smooth curve. In this case, solid HSA binds more than 300 mol dioxane/mol HSA at low water activities. By using a water activity-based comparison we distinguished between dioxane-assisted and dioxane-competitive effect on water sorption. The obtained results demonstrate that the hydration 'history' of solid protein is an important factor that controls as the state of protein macromolecule as well as the sorption of low-molecular organic molecules.

  8. Effects of water vapor on protectiveness of Cr2O3 scale at 1073 K

    Science.gov (United States)

    Arifin, S. K.; Hamid, M.; Berahim, A. N.; Ani, M. H.

    2018-01-01

    Fe-Cr alloy is commonly being used as boiler tube’s material. It is subjected to prolonged exposure to water vapor oxidation. The ability to withstand high temperature corrosion can normally be attributed to the formation of a dense and slow growing Cr-rich-oxide scale known as chromia, Cr2O3 scale. However, oxidation may limit the alloy’s service lifetime due to decreasing of its protectiveness capability. This paper is to presents an experimental study of thermo gravimetric and Fourier transform infrared analysis of Cr2O3 at 1073 K in dry and humid environment. Samples were used from commercially available Cr2O3 powder. It was cold-pressed into pellet shape of 12 mm diameter and 3 mm thick with hydraulic press for 40 min at 48 MPa. It then sintered at 1173 K in inert gas environment for 8 h. The samples are cooled and placed in 5 mm diameter platinum pan. It is subjected to reaction in dry and wet environment at 1073 K by applying 100%-Ar and Ar-5%H2 gas. Each reaction period is 48 h utilizing Thermo Gravimetric Analyzer, TGA to quantify the mass changes. After the reaction, the samples then characterized with Fourier Transform Infrared Spectroscopy, FT-IR and Field Emission Electron Scanning Microscopy, FE-SEM. The TGA result shows mass decreasing ratio of Cr2O3 in wet (PH2O = 9.5x105Pa) and dry environment is at a factor of 1.2 while parabolic rate at 1.4. FT-IR results confirmed that water vapor significantly broaden the peaks, thus promotes the volatilization of Cr2O3 in wet sample. FESEM shows mostly packed and intact in dry while in wet sample, slightly porous particle arrangement compare to dry. It is concluded that water vapor species decreased Cr2O3 protectiveness capability.

  9. The SPARC water vapor assessment II: intercomparison of satellite and ground-based microwave measurements

    Directory of Open Access Journals (Sweden)

    G. E. Nedoluha

    2017-12-01

    Full Text Available As part of the second SPARC (Stratosphere–troposphere Processes And their Role in Climate water vapor assessment (WAVAS-II, we present measurements taken from or coincident with seven sites from which ground-based microwave instruments measure water vapor in the middle atmosphere. Six of the ground-based instruments are part of the Network for the Detection of Atmospheric Composition Change (NDACC and provide datasets that can be used for drift and trend assessment. We compare measurements from these ground-based instruments with satellite datasets that have provided retrievals of water vapor in the lower mesosphere over extended periods since 1996. We first compare biases between the satellite and ground-based instruments from the upper stratosphere to the upper mesosphere. We then show a number of time series comparisons at 0.46 hPa, a level that is sensitive to changes in H2O and CH4 entering the stratosphere but, because almost all CH4 has been oxidized, is relatively insensitive to dynamical variations. Interannual variations and drifts are investigated with respect to both the Aura Microwave Limb Sounder (MLS; from 2004 onwards and each instrument's climatological mean. We find that the variation in the interannual difference in the mean H2O measured by any two instruments is typically  ∼  1%. Most of the datasets start in or after 2004 and show annual increases in H2O of 0–1 % yr−1. In particular, MLS shows a trend of between 0.5 % yr−1 and 0.7 % yr−1 at the comparison sites. However, the two longest measurement datasets used here, with measurements back to 1996, show much smaller trends of +0.1 % yr−1 (at Mauna Loa, Hawaii and −0.1 % yr−1 (at Lauder, New Zealand.

  10. Validation of Aura Microwave Limb Sounder stratospheric water vapor measurements by the NOAA frost point hygrometer.

    Science.gov (United States)

    Hurst, Dale F; Lambert, Alyn; Read, William G; Davis, Sean M; Rosenlof, Karen H; Hall, Emrys G; Jordan, Allen F; Oltmans, Samuel J

    2014-02-16

    Differences between stratospheric water vapor measurements by NOAA frost point hygrometers (FPHs) and the Aura Microwave Limb Sounder (MLS) are evaluated for the period August 2004 through December 2012 at Boulder, Colorado, Hilo, Hawaii, and Lauder, New Zealand. Two groups of MLS profiles coincident with the FPH soundings at each site are identified using unique sets of spatiotemporal criteria. Before evaluating the differences between coincident FPH and MLS profiles, each FPH profile is convolved with the MLS averaging kernels for eight pressure levels from 100 to 26 hPa (~16 to 25 km) to reduce its vertical resolution to that of the MLS water vapor retrievals. The mean FPH - MLS differences at every pressure level (100 to 26 hPa) are well within the combined measurement uncertainties of the two instruments. However, the mean differences at 100 and 83 hPa are statistically significant and negative, ranging from -0.46 ± 0.22 ppmv (-10.3 ± 4.8%) to -0.10 ± 0.05 ppmv (-2.2 ± 1.2%). Mean differences at the six pressure levels from 68 to 26 hPa are on average 0.8% (0.04 ppmv), and only a few are statistically significant. The FPH - MLS differences at each site are examined for temporal trends using weighted linear regression analyses. The vast majority of trends determined here are not statistically significant, and most are smaller than the minimum trends detectable in this analysis. Except at 100 and 83 hPa, the average agreement between MLS retrievals and FPH measurements of stratospheric water vapor is better than 1%.

  11. Retrieving Precipitable Water Vapor Data Using GPS Zenith Delays and Global Reanalysis Data in China

    Directory of Open Access Journals (Sweden)

    Peng Jiang

    2016-05-01

    Full Text Available GPS has become a very effective tool to remotely sense precipitable water vapor (PWV information, which is important for weather forecasting and nowcasting. The number of geodetic GNSS stations set up in China has substantially increased over the last few decades. However, GPS PWV derivation requires surface pressure to calculate the precise zenith hydrostatic delay and weighted mean temperature to map the zenith wet delay to precipitable water vapor. GPS stations without collocated meteorological sensors can retrieve water vapor using standard atmosphere parameters, which lead to a decrease in accuracy. In this paper, a method of interpolating NWP reanalysis data to site locations for generating corresponding meteorological elements is explored over China. The NCEP FNL dataset provided by the NCEP (National Centers for Environmental Prediction and over 600 observed stations from different sources was selected to assess the quality of the results. A one-year experiment was performed in our study. The types of stations selected include meteorological sites, GPS stations, radio sounding stations, and a sun photometer station. Compared with real surface measurements, the accuracy of the interpolated surface pressure and air temperature both meet the requirements of GPS PWV derivation in most areas; however, the interpolated surface air temperature exhibits lower precision than the interpolated surface pressure. At more than 96% of selected stations, PWV differences caused by the differences between the interpolation results and real measurements were less than 1.0 mm. Our study also indicates that relief amplitude exerts great influence on the accuracy of the interpolation approach. Unsatisfactory interpolation results always occurred in areas of strong relief. GPS PWV data generated from interpolated meteorological parameters are consistent with other PWV products (radio soundings, the NWP reanalysis dataset, and sun photometer PWV data. The

  12. Energy recovery from waste glycerol by utilizing thermal water vapor plasma.

    Science.gov (United States)

    Tamošiūnas, Andrius; Valatkevičius, Pranas; Gimžauskaitė, Dovilė; Jeguirim, Mejdi; Mėčius, Vladas; Aikas, Mindaugas

    2017-04-01

    Glycerol, considered as a waste feedstock resulting from biodiesel production, has received much attention in recent years due to its properties, which offer to recover energy. The aim of this study was to investigate the use of a thermal water vapor plasma for waste (crude) glycerol conversion to synthesis gas, or syngas (H2 + CO). In parallel of crude glycerol, a pure glycerol (99.5%) was used as a reference material in order to compare the concentrations of the formed product gas. A direct current (DC) arc plasma torch stabilized by a mixture of argon/water vapor was utilized for the effective glycerol conversion to hydrogen-rich synthesis gas. It was found that after waste glycerol treatment, the main reaction products were gases with corresponding concentrations of H2 50.7%, CO 23.53%, CO2 11.45%, and CH4 3.82%, and traces of C2H2 and C2H6, which concentrations were below 0.5%. The comparable concentrations of the formed gas products were obtained after pure glycerol conversion-H2 46.4%, CO 26.25%, CO2 11.3%, and CH4 4.7%. The use of thermal water vapor plasma producing synthesis gas is an effective method to recover energy from both crude and pure glycerol. The performance of the glycerol conversion system was defined in terms of the produced gas yield, the carbon conversion efficiency, the cold gas efficiency, and the specific energy requirements.

  13. Comparison of GNSS integrated water vapor and NWM reanalysis data over Central and South America

    Science.gov (United States)

    Fernandez, Laura Isabel; Mendoza, Luciano Pedro Oscar; Natali, María Paula; Meza, Amalia Margarita; Bianchi, Clara Eugenia

    2017-04-01

    Integrated water vapor (IWV) derived from Global Navigation Satellite Systems (GNSS) and Numerical Weather Models (NWM) reanalysis data were compared in order to assess the consistency between the different datasets over the extended geographical region of Central and South America. The investigation was performed for the seven-year period between 2007 and 2013. We analyzed two different reanalysis: the European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis data (ERA Interim) and the Modern-Era Retrospective analysis for Research and Applications (MERRA2) from the National Aeronautics and Space Administration (NASA). The statistical analysis of the differences was performed in 110 GNSS sites (GPS +GLONASS), although the most interesting results came from the 73 sites which have more than 5 years of data. The study of the spatial distribution of the differences in the selected area involves different climate types, from polar to tropical, and it is characterized by large temporal variability of the integrated total humidity content. The inter-comparison was also performed on several time scales: from hours to years. In this study, not only the IWV values given by the different reanalysis where compared with the respective GNSS derived values but also the numeric integral of the IWV. This is nothing but the total vertically integrated water vapor of a unit air column each station but considering its real geopotential height. To that end, multilevel data from each reanalysis was also used. Moreover, the scarce coverage of operational radio sounding stations is noticeable in large areas of the selected region. Hence the contribution of IWV-GNSS is essential to improve the weather understanding. Considering that the atmospheric water vapor has a highly variable and complex distribution which knowledge is essential for weather prediction and local meteorological studies, this study aims to provide IWV-GNSS observations able to be assimilated by operational

  14. Operation of a breadboard liquid-sorbent/membrane-contactor system for removing carbon dioxide and water vapor from air

    Science.gov (United States)

    Mccray, Scott B.; Ray, Rod; Newbold, David D.; Millard, Douglas L.; Friesen, Dwayne T.; Foerg, Sandra

    1992-01-01

    Processes to remove and recover carbon dioxide (CO2) and water vapor from air are essential for successful long-duration space missions. This paper presents results of a developmental program focused on the use of a liquid-sorbent/membrane-contactor (LSMC) system for removal of CO2 and water vapor from air. In this system, air from the spacecraft cabin atmosphere is circulated through one side of a hollow-fiber membrane contactor. On the other side of the membrane contactor is flowed a liquid sorbent, which absorbs the CO2 and water vapor from the feed air. The liquid sorbent is then heated to desorb the CO2 and water vapor. The CO2 is subsequently removed from the system as a concentrated gas stream, whereas the water vapor is condensed, producing a water stream. A breadboard system based on this technology was designed and constructed. Tests showed that the LSMC breadboard system can produce a CO2 stream and a liquid-water stream. Details are presented on the operation of the system, as well as the effects on performance of variations in feed conditions.

  15. Effect of hygroscopic materials on water vapor permeation and dehumidification performance of poly(vinyl alcohol) membranes

    KAUST Repository

    Bui, T. D.

    2017-01-16

    In this study, two hygroscopic materials, inorganic lithium chloride (LiCl) and organic triethylene glycol (TEG) were separately added to poly(vinyl alcohol) (PVA) to form blend membranes for air dehumidification. Water vapor permeation, dehumidification performance and long-term durability of the membranes were studied systematically. Membrane hydrophilicity and water vapor sorbability increased significantly with higher the hygroscopic material contents. Water vapor permeance of the membranes increased with both added hygroscopic material and absorbed water. Water permeation energy varied from positive to negative with higher hygroscopic content. This observation is attributed to a lower diffusion energy and a relatively constant sorption energy when hygroscopic content increases. Comparatively, PVA/TEG has less corrosive problems and is more environmentally friendly than PVA/LiCl. A membrane with PVA/TEG is observed to be highly durable and is suitable for dehumidification applications.

  16. Transparent semiconducting amorphous cadmium-gallium-tin oxide films by magnetron sputtering with water vapor

    Science.gov (United States)

    Yanagi, Hiroshi; Koyamaishi, Yusuke; Sato, Chiyuki; Kimura, Yota

    2017-06-01

    Amorphous oxide semiconductors (including transparent ones) are attractive materials for next-generation optoelectronic applications. One of the difficulties with amorphous oxide semiconductors is the lack of high mobility (>10 cm2 V-1 s-1) at low carrier density (radio-frequency magnetron sputtering with a water-vapor pressure ≥0.25 Pa. In these amorphous films, the threshold carrier density for obtaining high mobility (˜10 cm2 V-1 s-1) is possibly four orders of magnitude lower than that in conventional amorphous oxide semiconductors such as amorphous In-Ga-Zn-O.

  17. Vapor compression CuCl heat pump integrated with a thermochemical water splitting cycle

    Energy Technology Data Exchange (ETDEWEB)

    Zamfirescu, C., E-mail: Calin.Zamfirescu@uoit.ca [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology (UOIT), 2000 Simcoe Street North, Oshawa, ON, Canada L1H 74K (Canada); Naterer, G.F., E-mail: Greg.Naterer@uoit.ca [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology (UOIT), 2000 Simcoe Street North, Oshawa, ON, Canada L1H 74K (Canada); Dincer, I., E-mail: Ibrahim.Dincer@uoit.ca [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology (UOIT), 2000 Simcoe Street North, Oshawa, ON, Canada L1H 74K (Canada)

    2011-01-10

    In this paper, the feasibility of using cuprous chloride (CuCl) as a working fluid in a new high temperature heat pump with vapor compression is analyzed. The heat pump is integrated with a copper-chlorine (Cu-Cl) thermochemical water splitting cycle for internal heat recovery, temperature upgrades and hydrogen production. The minimum temperature of heat supply necessary for driving the water splitting cycle can be lowered because the heat pump increases the working fluid temperature from 755 K up to {approx}950 K, at a high COP of {approx}6.5. Based on measured data available in past literature, the authors have determined the T-s diagram of CuCl, which is then used for the thermodynamic modeling of the cycle. In the heat pump cycle, molten CuCl is flashed in a vacuum where the vapor quality reaches {approx}2.5%, and then it is boiled to produce saturated vapor. The vapor is then compressed in stages (with inter-cooling and heat recovery), and condensed in a direct contact heat exchanger to transfer heat at a higher temperature. The heat pump is then integrated with a copper-chlorine water splitting plant. The heat pump evaporator is connected thermally with the hydrogen production reactor of the water splitting plant, which performs an exothermic reaction that generates heat at 760 K. Additional source heat is obtained from heat recovery from the hot reaction products of the oxy-decomposer. The heat pump transfers heat at {approx}950 K to the oxy-decomposer to drive its endothermic chemical reaction. It is shown that the heat required at the heat pump source can be obtained completely from internal heat recovery within the plant. First and second law analyses and a parametric study are performed for the proposed system to study the influence of the compressor's isentropic efficiency and temperature levels on the heat pump's COP. Two new indicators are presented: one represents the heat recovery ratio (the ratio between the thermal energy obtained by

  18. Venus cloud structure and water vapor abundance from Mariner 10 observations

    Science.gov (United States)

    Taylor, F. W.

    1976-01-01

    Observations of the Venus atmosphere with the infrared radiometer on Mariner 10 have been analyzed by Taylor (1975) in terms of the vertical distribution of opacity at wavelengths near 11 microns and 45 microns in the thermal infrared. In this paper, we discuss models of the Venus atmosphere which are consistent with the inferred opacity structure. Either a two-layer cloud structure, or a single cloud deck overlaid by a layer containing approximately 40 precipitable microns of water vapor, would have the required limb-darkening characteristics at the wavelengths of observation.

  19. A corresponding-states analysis of the liquid-vapor equilibrium properties of common water models

    Science.gov (United States)

    Fugel, Malte; Weiss, Volker C.

    2017-02-01

    Many atomistic potential models have been proposed to reproduce the properties of real water and to capture as many of its anomalies as possible. The large number of different models indicates that this task is by no means an easy one. Some models are reasonably successful for various properties, while others are designed to account for only a very few specific features of water accurately. Among the most popular models are SPC/E, TIP4P, TIP4P/2005, TIP4P/Ice, and TIP5P-E. Here, we report the equilibrium properties of the liquid-vapor coexistence, such as the densities of the liquid phase and the vapor phase, the interfacial tension between them, and the vapor pressure at saturation. From these data, the critical parameters are determined and subsequently used to cast the liquid-vapor coexistence properties into a corresponding-states form following Guggenheim's suggestions. Doing so reveals that the three TIP4P-based models display the same corresponding-states behavior and that the SPC/E model behaves quite similarly. Only the TIP5P-E model shows clear deviations from the corresponding-states properties of the other models. A comparison with data for real water shows that the reduced surface tension is well described, while the reduced coexistence curve is too wide. The models underestimate the critical compressibility factor and overestimate Guggenheim's ratio as well as the reduced boiling temperature (Guldberg's ratio). As demonstrated by the collapse of the data for the TIP4P-based models, these deviations are inherent to the specific model and cannot be corrected by a simple reparametrization. For comparison, the results for two recent polarizable models, HBP and BK3, are shown, and both models are seen to perform well in terms of absolute numbers and in a corresponding-states framework. The kind of analysis applied here can therefore be used as a guideline in the design of more accurate and yet simple multi-purpose models of water.

  20. Near-IR Direct Detection of Water Vapor in Tau Bootis b

    Science.gov (United States)

    2014-02-24

    rights reserved. Printed in the U.S.A. NEAR-IR DIRECT DETECTION OF WATER VAPOR IN TAU BOÖTIS b Alexandra C. Lockwood1, John A. Johnson1,2, Chad F...Bender3,4, John S. Carr5, Travis Barman6, Alexander J. W. Richert3,4, and Geoffrey A. Blake1 1 Division of Geological and Planetary Sciences, California...their host star. Hundreds of transiting planets have been discovered and characterized, and the ongoing Kepler mission has found potential exoplanet

  1. Water Vapor Sensors Based on the Swelling of Relief Gelatin Gratings

    Directory of Open Access Journals (Sweden)

    Sergio Calixto

    2015-01-01

    Full Text Available We report on a novel device to measure relative humidity. The sensor is based on surface diffraction gratings made of gelatin. This material swells and shrinks according to the content of water vapor in air. By sending a light beam to the grating, diffracted orders appear. Due to the gelatin swelling or shrinking, first order intensity changes according to the relative humidity. Calibration curves relating intensity versus relative humidity have been found. The fabrication process of diffraction gratings and the testing of the prototype sensing devices are described.

  2. A corresponding-states analysis of the liquid-vapor equilibrium properties of common water models.

    Science.gov (United States)

    Fugel, Malte; Weiss, Volker C

    2017-02-14

    Many atomistic potential models have been proposed to reproduce the properties of real water and to capture as many of its anomalies as possible. The large number of different models indicates that this task is by no means an easy one. Some models are reasonably successful for various properties, while others are designed to account for only a very few specific features of water accurately. Among the most popular models are SPC/E, TIP4P, TIP4P/2005, TIP4P/Ice, and TIP5P-E. Here, we report the equilibrium properties of the liquid-vapor coexistence, such as the densities of the liquid phase and the vapor phase, the interfacial tension between them, and the vapor pressure at saturation. From these data, the critical parameters are determined and subsequently used to cast the liquid-vapor coexistence properties into a corresponding-states form following Guggenheim's suggestions. Doing so reveals that the three TIP4P-based models display the same corresponding-states behavior and that the SPC/E model behaves quite similarly. Only the TIP5P-E model shows clear deviations from the corresponding-states properties of the other models. A comparison with data for real water shows that the reduced surface tension is well described, while the reduced coexistence curve is too wide. The models underestimate the critical compressibility factor and overestimate Guggenheim's ratio as well as the reduced boiling temperature (Guldberg's ratio). As demonstrated by the collapse of the data for the TIP4P-based models, these deviations are inherent to the specific model and cannot be corrected by a simple reparametrization. For comparison, the results for two recent polarizable models, HBP and BK3, are shown, and both models are seen to perform well in terms of absolute numbers and in a corresponding-states framework. The kind of analysis applied here can therefore be used as a guideline in the design of more accurate and yet simple multi-purpose models of water.

  3. Kinetics of Chronic Oxidation of NBG-17 Nuclear Graphite by Water Vapor

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burchell, Timothy D [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mee, Robert [Univ. of Tennessee, Knoxville, TN (United States)

    2015-05-01

    This report presents the results of kinetic measurements during accelerated oxidation tests of NBG-17 nuclear graphite by low concentration of water vapor and hydrogen in ultra-high purity helium. The objective is to determine the parameters in the Langmuir-Hinshelwood (L-H) equation describing the oxidation kinetics of nuclear graphite in the helium coolant of high temperature gas-cooled reactors (HTGR). Although the helium coolant chemistry is strictly controlled during normal operating conditions, trace amounts of moisture (predictably < 0.2 ppm) cannot be avoided. Prolonged exposure of graphite components to water vapor at high temperature will cause very slow (chronic) oxidation over the lifetime of graphite components. This behavior must be understood and predicted for the design and safe operation of gas-cooled nuclear reactors. The results reported here show that, in general, oxidation by water of graphite NBG-17 obeys the L-H mechanism, previously documented for other graphite grades. However, the characteristic kinetic parameters that best describe oxidation rates measured for graphite NBG-17 are different than those reported previously for grades H-451 (General Atomics, 1978) and PCEA (ORNL, 2013). In some specific conditions, certain deviations from the generally accepted L-H model were observed for graphite NBG-17. This graphite is manufactured in Germany by SGL Carbon Group and is a possible candidate for the fuel elements and reflector blocks of HTGR.

  4. Monitoring the variability of precipitable water vapor over the Klang Valley, Malaysia during flash flood

    Science.gov (United States)

    Suparta, W.; Rahman, R.; Singh, M. S. J.

    2014-06-01

    Klang Valley is a focal area of Malaysian economic and business activities where the local weather condition is very important to maintain its reputation. Heavy rainfalls for more than an hour were reported up to 40 mm in September 2013 and 35 mm in October 2013. Both events are monitored as the first and second cases of flash flood, respectively. Based on these cases, we investigate the water vapor, rainfall, surface meteorological data (surface pressure, relative humidity, and temperature) and river water level. The precipitable water vapor (PWV) derived from Global Positioning System (GPS) is used to indicate the impact of flash flood on the rainfall. We found that PWV was dropped 4 mm in 2 hours before rainfall reached to 40 mm and dropped 3 mm in 3 hours before 35 mm of rainfall in respective cases. Variation of PWV was higher in September case compared to October case of about 2 mm. We suggest the rainfall phenomena can disturb the GPS propagation and therefore, the impact of PWV before, during and after the flash flood event at three selected GPS stations in Klang Valley is investigated for possible mitigation in the future.

  5. Electronic absorption line shapes at the water liquid/vapor interface.

    Science.gov (United States)

    Nelson, Katherine V; Benjamin, Ilan

    2012-04-12

    In order to investigate the factors that contribute to the electronic absorption line shape of a chromophore adsorbed at the water liquid/vapor interface, molecular dynamics simulations of a series of dipolar solutes undergoing various electronic transitions at various locations along the interface normal are studied. For electronic transitions that involve a change in the permanent dipole moment of the solute, the transition from the bulk water to the liquid/vapor interface involves a spectral shift consistent with the lower polarity of the interface. The change in the spectral width relative to that in the bulk is determined by several factors, which, depending on the nature of the transition and the dipole moment of the initial state, can result in a narrowing or broadening of the spectrum. These factors include the location of the interface region (which directly correlates with local polarity), the heterogeneity of the local solvation shell, and the width of the surface region. The contribution of the heterogeneity of the local solvation shell can be determined by comparing surface water with bulk methanol, whose polarity is comparable to one of the surface regions.

  6. Adsorption tests of water vapor on synthetic zeolites for an atmospheric detritiation dryer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.R. [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)]. E-mail: krkim1@kaeri.re.kr; Lee, M.S. [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Paek, S. [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Yim, S.P. [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Ahn, D.H. [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Chung, H. [Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2007-08-15

    Tritiated hydrogen and hydrocarbon are usually oxidized to a tritiated water vapor to make the tritium adsorbable and easy to treat. The adsorption system as a subsequent process plays an important role in a tritium recovery and its performance affects the overall detritiation efficiency significantly. In order to quantify an adsorbent's utilization and its dynamic capacity against an inlet humidity and a flow rate, a series of quantitative tests based on the breakthrough behavior were carried out in an isothermal fixed bed of synthetic zeolites such as molecular sieve 4A, 5A, 13X and mordenite. The amount of water vapor breaking during the adsorption was estimated to provide a breakthrough capacity at the various inlet flow rates and humidity conditions. The molecular sieve 13X exhibited a better adsorption performance at a given bed height. The existence of CO{sub 2} in a humid atmosphere had a minor effect on the net adsorption capacity and the hydrogen isotopic water (HDO) in the elution stream showed a delayed behavior during a thermal desorption.

  7. On the Internal Gas Dynamics and Efficiency of a Vortex Water-Vapor Plasma Generator

    Science.gov (United States)

    Charakhovski, L.; Essiptchouk, A.; Otani, C.; Petraconi, G.; Marquesi, A.; Sauchyn, V.; Khvedchyn, I.; Olenovich, A.; Liavonchyk, A.; Skamarokhau, D.; Halinouski, A.

    2017-05-01

    Results of experimental investigations of a new-type generator of an arc water plasma, having a high thermal efficiency close to 100%, are presented. This generator represents a system comprising a vortex arc plasma generator, in which an electric arc is stabilized by water vapor and a straight-through-flow tubular electric steam generator. Such a high efficiency of the plasma generator system was achieved due to the refinement of the internal gas dynamics of the plasma generator and the heat and mass transfer in its discharge channel as a result of the improvement of the vortex stabilization and thermal insulation of an arc discharge in it by the specially organized ″instantly permeable″ channel wall cooled by only the working water used for generation of the plasma.

  8. Oxidation of zirconium alloys in 2.5 kPa water vapor for tritium readiness.

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Bernice E.

    2007-11-01

    A more reactive liner material is needed for use as liner and cruciform material in tritium producing burnable absorber rods (TPBAR) in commercial light water nuclear reactors (CLWR). The function of these components is to convert any water that is released from the Li-6 enriched lithium aluminate breeder material to oxide and hydrogen that can be gettered, thus minimizing the permeation of tritium into the reactor coolant. Fourteen zirconium alloys were exposed to 2.5 kPa water vapor in a helium stream at 300 C over a period of up to 35 days. Experimental alloys with aluminum, yttrium, vanadium, titanium, and scandium, some of which also included ternaries with nickel, were included along with a high nitrogen impurity alloy and the commercial alloy Zircaloy-2. They displayed a reactivity range of almost 500, with Zircaloy-2 being the least reactive.

  9. Comparison of Water Vapor Measurements by Airborne Sun Photometer and Diode Laser Hygrometer on the NASA DC-8

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, J. M.; Schmid, Beat; Russell, P. B.; Podolske, James R.; Redemann, Jens; Diskin, G. S.

    2008-10-29

    In January-February 2003 the 14-channel NASA Ames Airborne Tracking Sunphotometer 30 (AATS) and the NASA Langley/Ames Diode Laser Hygrometer (DLH) were flown on the NASA DC-8 aircraft. AATS measured column water vapor on the aircraft-to-sun path, while DLH measured local water vapor in the free stream between the aircraft fuselage and an outboard engine cowling. The AATS and DLH measurements were compared for two DC-8 vertical profiles by differentiating the AATS column measurement and/or integrating the DLH local measurement over the altitude range of each profile (7.7-10 km and 1.2-12.5 km). These comparisons extend, for the first time, tests of AATS water vapor retrievals to altitudes >~6 km and column contents <0.1 g cm-2. To our knowledge this is the first time suborbital spectroscopic water vapor measurements using the 940-nm band have been tested in conditions so high and dry. For both profiles layer water vapor (LWV) from AATS and DLH were highly correlated, with r2 0.998, rms difference 7.2% and bias (AATS minus DLH) 0.9%. For water vapor densities AATS and DLH had r2 0.968, rms difference 27.6%, and bias (AATS minus DLH) -4.2%. These results compare favorably with previous comparisons of AATS water vapor to in situ results for altitudes <~6 km, columns ~0.1 to 5 g cm-2 and densities ~0.1 to 17 g m-3.

  10. Two decades of water vapor measurements with the FISH fluorescence hygrometer: a review

    Directory of Open Access Journals (Sweden)

    J. Meyer

    2015-07-01

    Full Text Available For almost two decades, the airborne Fast In-situ Stratospheric Hygrometer (FISH has stood for accurate and precise measurements of total water mixing ratios (WMR, gas phase + evaporated ice in the upper troposphere and lower stratosphere (UT/LS. Here, we present a comprehensive review of the measurement technique (Lyman-α photofragment fluorescence, calibration procedure, accuracy and reliability of FISH. Crucial for FISH measurement quality is the regular calibration to a water vapor reference, namely the commercial frost-point hygrometer DP30. In the frame of this work this frost-point hygrometer is compared to German and British traceable metrological water standards and its accuracy is found to be 2–4 %. Overall, in the range from 4 to 1000 ppmv, the total accuracy of FISH was found to be 6–8 %, as stated in previous publications. For lower mixing ratios down to 1 ppmv, the uncertainty reaches a lower limit of 0.3 ppmv. For specific, non-atmospheric conditions, as set in experiments at the AIDA chamber – namely mixing ratios below 10 and above 100 ppmv in combination with high- and low-pressure conditions – the need to apply a modified FISH calibration evaluation has been identified. The new evaluation improves the agreement of FISH with other hygrometers to ± 10 % accuracy in the respective mixing ratio ranges. Furthermore, a quality check procedure for high total water measurements in cirrus clouds at high pressures (400–500 hPa is introduced. The performance of FISH in the field is assessed by reviewing intercomparisons of FISH water vapor data with other in situ and remote sensing hygrometers over the last two decades. We find that the agreement of FISH with the other hygrometers has improved over that time span from overall up to ± 30 % or more to about ± 5–20 % @ 10 ppmv. As presented here, the robust and continuous calibration and operation procedures of the FISH instrument over the last two decades establish the

  11. An insight into the western Pacific wintertime moisture sources using dual water vapor isotopes

    Science.gov (United States)

    Rangarajan, Ravi; Laskar, Amzad H.; Bhattacharya, Sourendra K.; Shen, Chuan-Chou; Liang, Mao-Chang

    2017-04-01

    Continuous measurements of isotopic ratios in atmospheric water vapor in a western Pacific region (Taipei, Taiwan) in two winters (2011 and 2012) were made and analyzed to understand the moisture source characteristics. In wintertime, the so-called East Asian Monsoon dominates, largely affecting the climate and meteorology of this region. Being located in the subtropical region, Taipei provides an ideal opportunity for studying interactions between high latitude cold and dry continental air masses and low to mid-latitude warm and wet oceanic air. Indeed, the dual isotope function, d-excess shows the presence of two distinct moisture sources, contributing to the winter vapor isotope variability. Undoubtedly, the dominant moisture source is the high latitude continental cold air masses reaching Taipei with d-excess values of >20‰. Alongside, wet and warm air masses characterized by strong air-sea interaction from the surrounding oceans, possessing d-excess value of ∼10‰ also play a role. The interactions of these two distinct air masses cause the d-excess values to change by as much as ∼20‰ in a few days. Multiple regression analysis shows that source moisture composition and water vapor mixing ratio combined control over 60% of the observed variability. We developed a box model to show that both high and low d-excess events in the winter are primarily controlled by the humidity deficit over the ocean. The information obtained in this study could be used in interpreting the paleoclimate proxies within the East Asian region.

  12. Development of a Water Based, Critical Flow, Non-Vapor Compression cooling Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Hosni, Mohammad H.

    2014-03-30

    Expansion of a high-pressure liquid refrigerant through the use of a thermostatic expansion valve or other device is commonplace in vapor-compression cycles to regulate the quality and flow rate of the refrigerant entering the evaporator. In vapor-compression systems, as the condensed refrigerant undergoes this expansion, its pressure and temperature drop, and part of the liquid evaporates. We (researchers at Kansas State University) are developing a cooling cycle that instead pumps a high-pressure refrigerant through a supersonic converging-diverging nozzle. As the liquid refrigerant passes through the nozzle, its velocity reaches supersonic (or critical-flow) conditions, substantially decreasing the refrigerant’s pressure. This sharp pressure change vaporizes some of the refrigerant and absorbs heat from the surrounding conditions during this phase change. Due to the design of the nozzle, a shockwave trips the supersonic two-phase refrigerant back to the starting conditions, condensing the remaining vapor. The critical-flow refrigeration cycle would provide space cooling, similar to a chiller, by running a secondary fluid such as water or glycol over one or more nozzles. Rather than utilizing a compressor to raise the pressure of the refrigerant, as in a vapor-cycle system, the critical-flow cycle utilizes a high-pressure pump to drive refrigerant liquid through the cooling cycle. Additionally, the design of the nozzle can be tailored for a given refrigerant, such that environmentally benign substances can act as the working fluid. This refrigeration cycle is still in early-stage development with prototype development several years away. The complex multi-phase flow at supersonic conditions presents numerous challenges to fully understanding and modeling the cycle. With the support of DOE and venture-capital investors, initial research was conducted at PAX Streamline, and later, at Caitin. We (researchers at Kansas State University) have continued development

  13. Water vapor as an error source in microwave geodetic systems: Background and survey of calibration techniques. [very long base interferometry

    Science.gov (United States)

    Claflin, E. S.; Resch, G. M.

    1980-01-01

    Water vapor as an error source in radio interferometry systems is briefly examined. At microwave frequencies, the delay imposed by tropospheric water vapor becomes a limiting error source for high accuracy geodetic systems. The mapping of tropospheric induced errors into 'solved-for' parameters depends upon baseline length and observing strategy. Simulation analysis (and experience) indicates that in some cases, errors in estimating tropospheric delay can be magnified in their effect on baseline components. The various techniques by which tropospheric water can be estimated or measured are surveyed with particular consideration to their possible use as a calibration technique in support to very long baseline interferometry experiments. The method of remote sensing using a microwave radiometer seems to be the most effective way to provide an accurate estimate of water vapor delay.

  14. Growth mechanism of long aligned multiwall carbon nanotube arrays by water-assisted chemical vapor deposition.

    Science.gov (United States)

    Yun, YeoHeung; Shanov, Vesselin; Tu, Yi; Subramaniam, Srinivas; Schulz, Mark J

    2006-11-30

    Highly aligned arrays of multiwalled carbon nanotube (MWCNT) on layered Si substrates have been synthesized by chemical vapor deposition (CVD). The effect of the substrate design and the process parameters on the growth mechanism were studied. Adding water vapor to the reaction gas mixture of hydrogen and ethylene enhanced the growth which led to synthesis of longer CNT arrays with high density. Environmental scanning electron microscopy (ESEM), energy-dispersive spectroscopy (EDS), and atomic force microscopy (AFM) were used to analyze the CNT morphology and composition. Quadrupole mass spectroscopy (QMS) provided in-situ information on the gas spices within the reaction zone. On the basis of results, we verified the top growth mechanism and evaluated the reason of decline and stoppage of the CNT growth after extended period of deposition. Multilayered Si substrates with a top film of Al2O3, having appropriate roughness, provide favorable conditions to form catalyst islands with uniform distribution and size. Using water-assisted CVD process and optimized substrate design, our group succeeded to grow vertically aligned, patterned MWCNT up to 4-mm long. The arrays were of high purity and weak adhesion which allowed to be peeled off easily from the substrate.

  15. Exploring the Elevated Water Vapor Signal Associated with Biomass Burning Aerosol over the Southeast Atlantic Ocean

    Science.gov (United States)

    Pistone, Kristina; Redemann, Jens; Wood, Rob; Zuidema, Paquita; Flynn, Connor; LeBlanc, Samuel; Noone, David; Podolske, James; Segal Rozenhaimer, Michal; Shinozuka, Yohei; hide

    2017-01-01

    The quantification of radiative forcing due to the cumulative effects of aerosols, both directly and on cloud properties, remains the biggest source of uncertainty in our understanding of the physical climate. How the magnitude of these effects may be modified by meteorological conditions is an important aspect of this question. The Southeast Atlantic Ocean (SEA), with seasonal biomass burning (BB) smoke plumes overlying a persistent stratocumulus cloud deck, offers a perfect natural observatory in which to study the complexities of aerosol-cloud interactions. The NASA ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) campaign consists of three field deployments over three years (2016-2018) with the goal of gaining a better understanding of the complex processes (direct and indirect) by which BB aerosols affect clouds. We present results from the first ORACLES field deployment, which took place in September 2016 out of Walvis Bay, Namibia. Two NASA aircraft were flown with a suite of aerosol, cloud, radiation, and meteorological instruments for remote-sensing and in-situ observations. A strong correlation was observed between the aircraft-measured pollution indicators (carbon monoxide and aerosol properties) and atmospheric water vapor content, at all altitudes. Atmospheric reanalysis indicates that convective dynamics over the continent, near likely contribute to this elevated signal. Understanding the mechanisms by which water vapor covaries with plume strength is important to quantifying the magnitude of the aerosol direct and semi-direct effects in the region.

  16. Attribution of the United States "warming hole": aerosol indirect effect and precipitable water vapor.

    Science.gov (United States)

    Yu, Shaocai; Alapaty, Kiran; Mathur, Rohit; Pleim, Jonathan; Zhang, Yuanhang; Nolte, Chris; Eder, Brian; Foley, Kristen; Nagashima, Tatsuya

    2014-11-06

    Aerosols can influence the climate indirectly by acting as cloud condensation nuclei and/or ice nuclei, thereby modifying cloud optical properties. In contrast to the widespread global warming, the central and south central United States display a noteworthy overall cooling trend during the 20(th) century, with an especially striking cooling trend in summertime daily maximum temperature (Tmax) (termed the U.S. "warming hole"). Here we used observations of temperature, shortwave cloud forcing (SWCF), longwave cloud forcing (LWCF), aerosol optical depth and precipitable water vapor as well as global coupled climate models to explore the attribution of the "warming hole". We find that the observed cooling trend in summer Tmax can be attributed mainly to SWCF due to aerosols with offset from the greenhouse effect of precipitable water vapor. A global coupled climate model reveals that the observed "warming hole" can be produced only when the aerosol fields are simulated with a reasonable degree of accuracy as this is necessary for accurate simulation of SWCF over the region. These results provide compelling evidence of the role of the aerosol indirect effect in cooling regional climate on the Earth. Our results reaffirm that LWCF can warm both winter Tmax and Tmin.

  17. Determining the precipitable water vapor thresholds under different rainfall strengths in Taiwan

    Science.gov (United States)

    Yeh, Ta-Kang; Shih, Hsuan-Chang; Wang, Chuan-Sheng; Choy, Suelynn; Chen, Chieh-Hung; Hong, Jing-Shan

    2018-02-01

    Precipitable Water Vapor (PWV) plays an important role for weather forecasting. It is helpful in evaluating the changes of the weather system via observing the distribution of water vapor. The ability of calculating PWV from Global Positioning System (GPS) signals is useful to understand the special weather phenomenon. In this study, 95 ground-based GPS and rainfall stations in Taiwan were utilized from 2006 to 2012 to analyze the relationship between PWV and rainfall. The PWV data were classified into four classes (no, light, moderate and heavy rainfall), and the vertical gradients of the PWV were obtained and the variations of the PWV were analyzed. The results indicated that as the GPS elevation increased every 100 m, the PWV values decreased by 9.5 mm, 11.0 mm, 12.2 mm and 12.3 mm during the no, light, moderate and heavy rainfall conditions, respectively. After applying correction using the vertical gradients mentioned above, the average PWV thresholds were 41.8 mm, 52.9 mm, 62.5 mm and 64.4 mm under the no, light, moderate and heavy rainfall conditions, respectively. This study offers another type of empirical threshold to assist the rainfall prediction and can be used to distinguish the rainfall features between different areas in Taiwan.

  18. On the correlation of water vapor and CO2: Application to flux partitioning of evapotranspiration

    Science.gov (United States)

    Wang, Wen; Smith, James A.; Ramamurthy, Prathap; Baeck, Mary Lynn; Bou-Zeid, Elie; Scanlon, Todd M.

    2016-12-01

    The partitioning of evapotranspiration (ET) between plant transpiration (Et) and direct evaporation (Ed) presents one of the most important and challenging problems for characterizing ecohydrological processes. The exchange of water vapor (q) and CO2 (c) are closely coupled in ecosystem processes and knowledge of their controls can be gained through joint investigation of q and c. In this study we examine the correlation of water vapor and CO2 (Rqc) through analyses of high-frequency time series derived from eddy covariance measurements collected over a suburban grass field in Princeton, NJ during a 2 year period (2011-2013). Rqc at the study site exhibits pronounced seasonal and diurnal cycles, with maximum anticorrelation in June and maximum decorrelation in January. The diurnal cycle of Rqc varies seasonally and is characterized by a near-symmetric shape with peak anticorrelation around local noon. Wavelet and spectral analyses suggest that q and c are jointly transported for most eddy scales (1-200 m), which is important for ET partitioning methods based on flux variance similarity. The diurnal cycle of the transpiration fraction (ratio of Et to total ET) exhibits an asymmetric diurnal cycle, especially during the warm season, with peak values occurring in the afternoon. These ET partitioning results give similar diurnal and seasonal patterns compared with numerical simulations from the Noah Land Surface Model using the Jarvis canopy resistance formulation.

  19. African and Atlantic short-term climatic variations described from Meteosat water vapor channel

    Directory of Open Access Journals (Sweden)

    L. Picon

    1995-07-01

    Full Text Available Pluriannual series of Meteosat-2 water vapor (WV images are used to build average maps of decadal and monthly brightness temperatures in the 6.3 µm channel. This processing is applied to all the 3-hourly scenes, clear or cloudy, for July 1983 to July 1987. The ISCCP cloudiness analyses confirm that the warmest spots in the monthly WV images correspond to scenes either clear or covered with low clouds, whereas the coldest areas correspond to scenes where cloud tops above 440 hPa frequently occur. The WV statistics are then used to characterize seasonal and interannual variations of both the ITCZ (InterTropical Convergence Zone and the warm (dry areas, corresponding to subtropical subsidence. Thanks mainly to the seasonal variations, relationships between the variations in the ITCZ and in dry subtropical areas can be studied. It is shown that, for the Meteosat sector, a wetter subtropical high troposphere is associated with an enhanced activity of the ITCZ, and vice versa. For this area where the north-south assymetry is large, the negative water vapor feedback previously proposed seems not to occur.

  20. Mechanical and water vapor permeability properties of biodegradables films based on methylcellulose, glucomannan, pectin and gelatin

    Directory of Open Access Journals (Sweden)

    Hulda Noemi Mamani Chambi

    2011-09-01

    Full Text Available Mimic biological structures such as the cell wall of plant tissues may be an alternative to obtain biodegradable films with improved mechanical and water vapor barrier properties. This study aims to evaluate the mechanical properties and water vapor permeability (WVP of films produced by using the solvent-casting technique from blended methylcellulose, glucomannan, pectin and gelatin. First, films from polysaccharides at pH 4 were produced. The film with the best mechanical performance (tensile strength = 72.63 MPa; elongation = 9.85% was obtained from methylcellulose-glucomannan-pectin at ratio 1:4:1, respectively. Then, gelatin was added to this polysaccharide blend and the pH was adjusted to 4, 5 and 6. Results showed significant improvement in WVP when films were made at pH 5 and at polysaccharides/gelatin ratio of 90/10 and 10/90, reaching 0.094 and 0.118 g.mm/h.m².kPa as values, respectively. Films with the best mechanical properties were obtained from the blend of polysaccharides, whereas WVP was improved from the blend of polysaccharides and gelatin at pH 5.

  1. A quartz-enhanced photoacoustic spectroscopy sensor for measurement of water vapor concentration in the air

    Science.gov (United States)

    Gong, Ping; Xie, Liang; Qi, Xiao-Qiong; Wang, Rui; Wang, Hui; Chang, Ming-Chao; Yang, Hui-Xia; Sun, Fei; Li, Guan-Peng

    2015-01-01

    A compact and highly linear quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor for the measurement of water vapor concentration in the air is demonstrated. A cost-effective quartz tuning fork (QTF) is used as the sharp transducer to convert light energy into an electrical signal based on the piezoelectric effect, thereby removing the need for a photodetector. The short optical path featured by the proposed sensing system leads to a decreased size. Furthermore, a pair of microresonators is applied in the absorbance detection module (ADM) for QTF signal enhancement. Compared with the system without microresonators, the detected QTF signal is increased to approximately 7-fold. Using this optimized QEPAS sensor with the proper modulation frequency and depth, we measure the water vapor concentration in the air at atmospheric pressure and room temperature. The experimental result shows that the sensor has a high sensitivity of 1.058 parts-per-million. Project supported by the National Natural Science Foundation of China (Grant Nos. 61107070, 61127018, and 61377071).

  2. Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point

    Science.gov (United States)

    Tellinghuisen, Joel

    2010-01-01

    Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

  3. Algorithm for Recovery of Integrated Water Vapor Content in the Atmosphere over Land Surfaces Based on Satellite Spectroradiometer Data

    Science.gov (United States)

    Lisenko, S. A.

    2017-05-01

    An algorithm is proposed for making charts of the distribution of water vapor in the atmosphere based on multispectral images of the earth by the Ocean and Land Color Instrument (OLCI) on board of the European research satellite Sentinel-3. The algorithm is based on multiple regression fits of the spectral brightness coefficients at the upper boundary of the atmosphere, the geometric parameters of the satellite location (solar and viewing angles), and the total water vapor content in the atmosphere. A regression equation is derived from experimental data on the variation in the optical characteristics of the atmosphere and underlying surface, together with Monte-Carlo calculations of the radiative transfer characteristics. The equation includes the brightness coefficients in the near IR channels of the OLCI for the absorption bands of water vapor and oxygen, as well as for the transparency windows of the atmosphere. Together these make it possible to eliminate the effect of the reflection spectrum of the underlying surface and air pressure on the accuracy of the measurements. The algorithm is tested using data from a prototype OLCI, the medium resolution imaging spectrometer (MERIS). A sample chart of the distribution of water vapor in the atmosphere over Eastern Europe is constructed without using subsatellite data and digital models of the surface relief. The water vapor contents in the atmosphere determined using MERIS images and data provided by earthbound measurements with the aerosol robotic network (AERONET) are compared with a mean square deviation of 1.24 kg/m2.

  4. Nonequilibrium numerical model of homogeneous condensation in argon and water vapor expansions.

    Science.gov (United States)

    Jansen, Ryan; Wysong, Ingrid; Gimelshein, Sergey; Zeifman, Michael; Buck, Udo

    2010-06-28

    A computational approach capable of modeling homogeneous condensation in nonequilibrium environments is presented. The approach is based on the direct simulation Monte Carlo (DSMC) method, extended as appropriate to include the most important processes of cluster nucleation and evolution at the microscopic level. The approach uses a recombination-reaction energy-dependent mechanism of the DSMC method for the characterization of dimer formation, and the RRK model for the cluster evaporation. Three-step testing and validation of the model is conducted by (i) comparison of clusterization rates in an equilibrium heat bath with theoretical predictions for argon and water vapor and adjustment of the model parameters, (ii) comparison of the nonequilibrium argon cluster size distributions with experimental data, and (iii) comparison of the nonequilibrium water cluster size distributions with experimental measurements. Reasonable agreement was observed for all three parts of the validation.

  5. [Difference-frequency generation in PPLN and water vapor detection in air].

    Science.gov (United States)

    Deng, Lun-Hua; Gao, Xiao-Ming; Cao, Zhen-Song; Yuan, Yi-Qian; Zhang, Wei-Jun; Gong, Zhi-Ben

    2007-11-01

    The continuously tunable laser source has been realized in a periodically poled LiNO3 crystal based on difference frequency generation and quasi-phase-matching technique. The pump laser is an 1 W tunable Ti: Sapphire laser with a tunable region from 770 to 870 nm. The signal laser is an 1 W diode-pumped monolithic Nd : YAG laser. When the grating period is 20 microm and the temperature is tuned between room temperature and 200 degrees C, the generated wavelength of idler laser is around 2. 8 microm with the general power of .1-2 microW. The direct absorption spectra of (001 <-- 000) band of water in laboratory air were measured based on the laser source. The concentration of water vapor in the laboratory air was estimated with an absorption optical path of 8. 5 cm in open air.

  6. Dehydration in the tropical tropopause layer estimated from the water vapor match

    Directory of Open Access Journals (Sweden)

    Y. Inai

    2013-09-01

    Full Text Available We apply the match technique, whereby the same air mass is observed more than once and such cases are termed a "match", to study the dehydration process associated with horizontal advection in the tropical tropopause layer (TTL over the western Pacific. The matches are obtained from profile data taken by the Soundings of Ozone and Water in the Equatorial Region (SOWER campaign network observations using isentropic trajectories calculated from European Centre for Medium-Range Weather Forecasts (ECMWF operational analyses. For the matches identified, extensive screening procedures are performed to verify the representativeness of the air parcel and the validity of the isentropic treatment, and to check for possible water injection by deep convection, consistency between the sonde data and analysis field referring to the ozone conservation. Among the matches that passed the screening tests, we identified some cases corresponding to the first quantitative value of dehydration associated with horizontal advection in the TTL. The statistical features of dehydration for the air parcels advected in the lower TTL are derived from the matches. The threshold of nucleation is estimated to be 146 ± 1% (1σ in relative humidity with respect to ice (RHice, while dehydration seems to continue until RHice reaches about 75 ± 23% (1σ in the altitude region from 350 to 360 K. The efficiency of dehydration expressed by the relaxation time required for the supersaturated air parcel to approach saturation is empirically determined from the matches. A relaxation time of approximately one hour reproduces the second water vapor observation reasonably well, given the first observed water vapor amount and the history of the saturation mixing ratio during advection in the lower TTL.

  7. Stable isotope tracers of water vapor sources in the Atacama Desert, Northern Chile: a pilot study on the Chajnantor Plateau

    Science.gov (United States)

    Samuels, K. E.; Galewsky, J.; Sharp, Z. D.; Rella, C.; Ward, D.

    2010-12-01

    Subtropical deserts form in response to the interaction of large-scale processes, including atmospheric circulation and oceanic currents, with local features like topography. The degree to which each of these factors controls desert formation and the anticipated impacts of variations in each as climate changes, however, are poorly understood. Stable isotope compositions of water vapor in desert air can help to distinguish between moisture sources and processes that control aridity. The Atacama Desert, located in northern Chile between latitudes 23S and 27S, provides a natural laboratory in which to test the degree to which water vapor isotopologues enable the distinction between processes that control humidity, including the Hadley Circulation, the cold Humboldt Current off the coast of Chile, and the orographic effect of the Andes, in this subtropical desert. Water vapor isotopologues and concentrations were measured in real time using a cavity-ringdown spectrometer deployed on the Chajnantor Plateau over a three-week period from mid-July early August 2010. The elevation of the Plateau, 5000 m amsl (~550 hPa), places it above the boundary layer, allowing the evaluation of the Rayleigh fractionation model from the coast inland. Values reported by the instrument were verified with air samples taken at the coast and the Plateau, which were analyzed on an MAT-252 mass spectrometer. Water vapor concentrations and δD values varied spatially and temporally. Water vapor concentrations on the Plateau ranged from 200 to 3664 ppmv with a mean value of 536 ppmv. In contrast, water vapor concentrations at the coast were approximately 10000 ppmv, and at Yungay, 60 km inland, water vapor concentrations ranged from 1300 to 2000 ppmv from morning to evening. δD values on the Plateau ranged from -526‰ to -100‰ with a mean value of 290‰ with enriched values correlated to periods with higher water vapor concentrations. There are no strong diurnal variations in water vapor

  8. TREATMENT OF PRODUCED WATERS USING A SURFACTANT MODIFIED ZEOLITE/VAPOR PHASE BIOREACTOR SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Lynn E. Katz; Kerry A. Kinney; R.S. Bowman; E.J. Sullivan

    2003-04-01

    Co-produced water from the oil and gas industry accounts for a significant waste stream in the United States. It is by some estimates the largest single waste stream in the country, aside from nonhazardous industrial wastes. Characteristics of produced water include high total dissolved solids content, dissolved organic constituents such as benzene and toluene, an oil and grease component, and chemicals added during the oil-production process. While most of the produced water is disposed via reinjection, some of them must be treated to remove organic constituents before the water is discharged. Current treatment options are successful in reducing the organic content; however, they cannot always meet the levels of current or proposed regulations for discharged water. Therefore, an efficient, cost-effective treatment technology is needed. Surfactant-modified zeolite (SMZ) has been used successfully to treat contaminated ground water for organic and inorganic constituents. In addition, the low cost of natural zeolites makes their use attractive in water-treatment applications. Our previous DOE research work (DE-AC26-99BC15221) demonstrated that SMZ could successfully remove BTEX compounds from the produced water. In addition, SMZ could be regenerated through a simple air sparging process. The primary goal of this project is to develop a robust SMZ/VPB treatment system to efficiently remove the organic constituents from produced water in a cost-effective manner. This report summarizes work of this project from October 2002 to March 2003. In this starting stage of this study, we have continued our investigation of SMZ regeneration from our previous DOE project. Two saturation/stripping cycles have been completed for SMZ columns saturated with BTEX compounds. Preliminary results suggest that BTEX sorption actually increases with the number of saturation/regeneration cycles. Furthermore, the experimental vapor phase bioreactors for this project have been designed and are

  9. In Situ Water Vapor Measurements Using Coupled UV Fragment Fluorescence/Absorption Spectroscopy in Support of CRYSTAL-FACE

    Science.gov (United States)

    Anderson, James G.

    2004-01-01

    Understanding the coupling of dynamics, chemistry, and radiation within the context of the NASA Earth Science Enterprise (ESE) and the national Climate Change Science Program (CCSP) requires, as a first-order priority, high spatial resolution, high-accuracy observations of water in its various phases. Given the powerful diagnostic importance of the condensed phases of water for dynamics and the impact of phase changes in water on the radiation field, the accurate, in situ observation of water vapor is of central importance to CRYSTAL FACE (CF). This is clear both from the defined scientific objectives of the NRA and from developments in the coupled fields of stratosphere/troposphere exchange, cirrus cloud formation/removal and mechanisms for the distribution of water vapor in the middle/upper troposphere. Accordingly, we were funded under NASA Grant NAG5-11548 to perform the following tasks for the CF mission: 1. Prepare the water vapor instrument for integration into the WB57F and test flights scheduled for Spring 2002. 2. Calibrate and prepare the water vapor instrument for the Summer 2002 CF science flights based in Jacksonville, Florida. 3. Provide both science and engineering support for the above-mentioned efforts. 4. Analyze and interpret the CF data in collaboration with other mission scientists. 5. Attend the science workshop in Spring 2003. 6. Publish the data and analysis in peer-reviewed journals.

  10. Investigation of the heat pump water heater using economizer vapor injection system and mixture of R22/R600a

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Cao; Kai, Wang; Shouguo, Wang; Ziwen, Xing; Pengcheng, Shu [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianing west road, Xi' an 710049 (China)

    2009-05-15

    This paper presents the experimental study of a heat pump water heater (HPWH) using economizer vapor injection system and mixture of R22/R600a. Performances of HPWH using economizer vapor injection system are compared with that at different mixed mass ratios of R22/R600a. Study demonstrates that the heating capacity and energy efficiency ratio (EER) of the unit increased, and the discharge temperature of compressor decreased when using vapor injection and mixing refrigerant of R22/R600a. It is also found that the HPWH unit with economizer vapor injection system has a better performance for the high outlet water temperature under lower temperature conditions at 15% mass ratio of R600a for the mixing refrigerant. In addition, fundamental and practical influence of vapor injection pressure on the HPWH performance has been investigated experimentally. The simplified model is proposed for predicting the optimal vapor injection pressure of compressor using the mixing refrigerant R22/R600a. (author)

  11. Remote sensing of seasonal distribution of precipitable water vapor over the oceans and inference of boundary layer structure

    Science.gov (United States)

    Prabhakara, C.

    1979-01-01

    Over the ocean satellite infrared spectral measurements in the 18 micrometer water vapor band and the 11 micrometer window region were used to derive precipitable water vapor, w, in the atmosphere and the sea surface temperature, SST. Seasonal maps of w on the oceans derived from these data reveal the dynamical influence of the large scale atmospheric circulation. With the help of a model for the vertical distribution of water vapor, the configuration of the atmospheric boundary layer over the oceans can be inferred from w when the information of SST is combined. The gross seasonal mean structure of the boundary layer inferred in this fashion reveals the broad areas of the trade wind inversion and the convectively active areas such as the intertropical convergence zones.

  12. Adsorptive Water Removal from Dichloromethane and Vapor-Phase Regeneration of a Molecular Sieve 3A Packed Bed.

    Science.gov (United States)

    Jović, Slaviša; Laxminarayan, Yashasvi; Keurentjes, Jos; Schouten, Jaap; van der Schaaf, John

    2017-05-03

    The drying of dichloromethane with a molecular sieve 3A packed bed process is modeled and experimentally verified. In the process, the dichloromethane is dried in the liquid phase and the adsorbent is regenerated by water desorption with dried dichloromethane product in the vapor phase. Adsorption equilibrium experiments show that dichloromethane does not compete with water adsorption, because of size exclusion; the pure water vapor isotherm from literature provides an accurate representation of the experiments. The breakthrough curves are adequately described by a mathematical model that includes external mass transfer, pore diffusion, and surface diffusion. During the desorption step, the main heat transfer mechanism is the condensation of the superheated dichloromethane vapor. The regeneration time is shortened significantly by external bed heating. Cyclic steady-state experiments demonstrate the feasibility of this novel, zero-emission drying process.

  13. Tunable Structures and Properties of Electrospun Regenerated Silk Fibroin Mats Annealed in Water Vapor at Different Times and Temperatures

    Directory of Open Access Journals (Sweden)

    Xiangyu Huang

    2014-01-01

    Full Text Available Regenerated silk fibroin (SF mats were fabricated using electrospinning technique, followed by mild water vapor annealing to effectively tune the structures and improve the mechanical properties of the mats at different annealing times and temperatures. The breaking strength and the breaking energy of the mats treated with water vapor at 65°C for 12 h reached 6.0 MPa and 171.7 J/kg, respectively. The conformational transition of the SF mats was significantly influenced by the treating temperature, while the influence of time was comparatively limited. The influence is consistent with the time-temperature equivalent principle and would be helpful for the preparation of water-vapor-annealed silk-based biomaterials for various applications.

  14. Water-assisted growth of graphene on carbon nanotubes by the chemical vapor deposition method.

    Science.gov (United States)

    Feng, Jian-Min; Dai, Ye-Jing

    2013-05-21

    Combining carbon nanotubes (CNTs) with graphene has been proved to be a feasible method for improving the performance of graphene for some practical applications. This paper reports a water-assisted route to grow graphene on CNTs from ferrocene and thiophene dissolved in ethanol by the chemical vapor deposition method in an argon flow. A double injection technique was used to separately inject ethanol solution and water for the preparation of graphene/CNTs. First, CNTs were prepared from ethanol solution and water. The injection of ethanol solution was suspended and water alone was injected into the reactor to etch the CNTs. Thereafter, ethanol solution was injected along with water, which is the key factor in obtaining graphene/CNTs. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and Raman scattering analyses confirmed that the products were the hybrid materials of graphene/CNTs. X-ray photo-electron spectroscopy analysis showed the presence of oxygen rich functional groups on the surface of the graphene/CNTs. Given the activity of the graphene/CNT surface, CdS quantum dots adhered onto it uniformly through simple mechanical mixing.

  15. LBA-ECO CD-02 Oxygen Isotopes of Plant Tissue Water and Atmospheric Water Vapor

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set reports the oxygen isotope signatures of water extracted from plant tissue (xylem from the stems and leaf tissue) and of atmospheric water...

  16. The Observed Relationship Between Water Vapor and Ozone in the Tropical Tropopause Saturation Layer and the Influence of Meridional Transport

    Science.gov (United States)

    Selkirk, Henry B.; Schoeberl, M. R.; Olsen, M. A.; Douglass, A. R.

    2011-01-01

    We examine balloonsonde observations of water vapor and ozone from three Ticosonde campaigns over San Jose, Costa Rica [10 N, 84 W] during northern summer and a fourth during northern winter. The data from the summer campaigns show that the uppermost portion of the tropical tropopause layer between 360 and 380 K, which we term the tropopause saturation layer or TSL, is characterized by water vapor mixing ratios from proximately 3 to 15 ppmv and ozone from approximately 50 ppbv to 250 ppbv. In contrast, the atmospheric water vapor tape recorder at 380 K and above displays a more restricted 4-7 ppmv range in water vapor mixing ratio. From this perspective, most of the parcels in the TSL fall into two classes - those that need only additional radiative heating to rise into the tape recorder and those requiring some combination of additional dehydration and mixing with drier air. A substantial fraction of the latter class have ozone mixing ratios greater than 150 ppbv, and with water vapor greater than 7 ppmv this air may well have been transported into the tropics from the middle latitudes in conjunction with high-amplitude equatorial waves. We examine this possibility with both trajectory analysis and transport diagnostics based on HIRDLS ozone data. We apply the same approach to study the winter season. Here a very different regime obtains as the ozone-water vapor scatter diagram of the sonde data shows the stratosphere and troposphere to be clearly demarcated with little evidence of mixing in of middle latitude air parcels.

  17. Influence of long-range transboundary transport on atmospheric water vapor mercury collected at the largest city of Tibet

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jie [Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101 (China); CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101 (China); Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, Mikkeli FI 50130 (Finland); Kang, Shichang, E-mail: shichang.kang@lzb.ac.cn [State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000 (China); CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101 (China); Tian, Lide [Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101 (China); CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101 (China); Guo, Junming [Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Qianggong; Cong, Zhiyuan [Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101 (China); CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101 (China); Sillanpää, Mika [Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, Mikkeli FI 50130 (Finland); and others

    2016-10-01

    Monsoon circulation is an important process that affects long-range transboundary transport of anthropogenic contaminants such as mercury (Hg). During the Indian monsoon season of 2013, a total of 92 and 26 atmospheric water vapor samples were collected at Lhasa, the largest city of the Tibet, for Hg and major ions analysis, respectively. The relatively low pH/high electronic conductivity values, together with the fact that NH{sub 4}{sup +} in atmospheric water vapor was even higher than that determined in precipitation of Lhasa, indicated the effects of anthropogenic perturbations through long-range transboundary atmospheric transport. Concentrations of Hg in atmospheric water vapor ranged from 2.5 to 73.7 ng L{sup −1}, with an average of 12.5 ng L{sup −1}. The elevated Hg and major ions concentrations, and electronic conductivity values were generally associated with weak acidic samples, and Hg mainly loaded with anthropogenic ions such as NH{sub 4}{sup +}. The results of principal component analysis and trajectory analysis suggested that anthropogenic emissions from the Indian subcontinent may have largely contributed to the determined Hg in atmospheric water vapor. Furthermore, our study reconfirmed that below-cloud scavenging contribution was significant for precipitation Hg in Lhasa, and evaluated that on average 74.1% of the Hg in precipitation could be accounted for by below-cloud scavenging. - Highlights: • The low pH/high electronic conductivity was found in atmospheric water vapor. • Anthropogenic NH{sub 4}{sup +} was higher than that determined in precipitation of Lhasa. • Elevated Hg and major ions levels were usually associated with weak acidic samples. • Hg in atmospheric water vapor was largely influenced by transboundary transport. • Below-cloud scavenging accounted for most Hg in precipitation.

  18. Design, Development, and Testing of a Water Vapor Exchanger for Spacecraft Life Support Systems

    Science.gov (United States)

    Izenson, Michael G.; Micka, Daniel J.; Chepko, Ariane B.; Rule, Kyle C.; Anderson, Molly S.

    2016-01-01

    Thermal and environmental control systems for future exploration spacecraft must meet challenging requirements for efficient operation and conservation of resources. Maximizing the use of regenerative systems and conserving water are critical considerations. This paper describes the design, development, and testing of an innovative water vapor exchanger (WVX) that can minimize the amount of water absorbed in, and vented from, regenerative CO2 removal systems. Key design requirements for the WVX are high air flow capacity (suitable for a crew of six), very high water recovery, and very low pressure losses. We developed fabrication and assembly methods that enable high-efficiency mass transfer in a uniform and stable array of Nafion tubes. We also developed analysis and design methods to compute mass transfer and pressure losses. We built and tested subscale units sized for flow rates of 2 and 5 cu ft/min (3.4–8.5 cu m/hr). Durability testing demonstrated that a stable core geometry was sustained over many humid/dry cycles. Pressure losses were very low (less than 0.5 in. H2O (125 Pa) total) and met requirements at prototypical flow rates. We measured water recovery efficiency across a range of flow rates and humidity levels that simulate the range of possible cabin conditions. We measured water recovery efficiencies in the range of 80 to 90%, with the best efficiency at lower flow rates and higher cabin humidity levels. We compared performance of the WVX with similar units built using an unstructured Nafion tube bundle. The WVX achieves higher water recovery efficiency with nearly an order of magnitude lower pressure drop than unstructured tube bundles. These results show that the WVX provides uniform flow through flow channels for both the humid and dry streams and can meet requirements for service on future exploration spacecraft. The WVX technology will be best suited for long-duration exploration vehicles that require regenerative CO2 removal systems while

  19. Effect of ionic liquids on (vapor + liquid) equilibrium behavior of (water + 2-methyl-2-propanol)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lianzhong; Qiao Bingbang; Ge Yun; Deng Dongshun [College of Chemical Engineering and Material Science, Zhejiang University of Technology, Hangzhou 310014 (China); Ji Jianbing [College of Chemical Engineering and Material Science, Zhejiang University of Technology, Hangzhou 310014 (China)], E-mail: jjb@zjut.edu.cn

    2009-01-15

    Isobaric T, x, y data were reported for ternary systems of {l_brace}water + 2-methyl-2-propanol (tert-butyl alcohol, TBA) + ionic liquid (IL){r_brace} at p = 100 kPa. When the mole fraction of TBA on IL-free basis was fixed at 0.95, measurements were performed at IL mass fractions from 0.6 down to 0.05, in a way of repeated synthesis. The vapor-phase compositions were obtained by analytical methods and the liquid-phase compositions were calculated with the aid of mass balances. Activity coefficients of water and TBA were obtained without the need of a thermodynamic model of the liquid-phase. Six ILs, composed of an anion chosen from [OAc]{sup -} or [Cl]{sup -}, and a cation from [emim]{sup +}, or [bmim]{sup +}, or [hmim]{sup +}, were studied. Relative volatility and activity coefficients were presented in relation with the IL mole fraction, showing the effect of the ILs on a molar basis. The effect of the ILs on relative volatility of TBA to water was depicted by the effect of anions and cations on, respectively, the activity coefficients of water and TBA. The results indicated that, among the six ILs studied, [emim][Cl] has the most significant effect on enhancement of the relative volatility, which reaches a value of 7.2 at an IL mass fraction of 0.58. Another IL, [emim][OAc], has also significant effect, with an appreciable value of 5.2 for the relative volatility when the IL mass fraction is 0.6. Considering the relatively low viscosity and melting point of [emim][OAc], it might be a favorable candidate as solvent for the separation of water and TBA by extractive distillation. Simultaneous correlation by the NRTL model was presented for both systems of (water + ethanol + IL) and (water + TBA + IL), using consistent binary parameters for water and IL.

  20. On the quality of the Nimbus 7 LIMS Version 6 water vapor profiles and distributions

    Directory of Open Access Journals (Sweden)

    B. T. Marshall

    2009-12-01

    Full Text Available This report describes the quality of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS water vapor (H2O profiles of 1978/79 that were processed with a Version 6 (V6 algorithm and archived in 2002. The V6 profiles incorporate a better knowledge of the instrument attitude for the LIMS measurements along its orbits, leading to improvements for its temperature profiles and for the registration of its water vapor radiances with pressure. As a result, the LIMS V6 zonal-mean distributions of H2O exhibit better hemispheric symmetry than was the case from the original Version 5 (V5 dataset that was archived in 1982. Estimates of the precision and accuracy of the V6 H2O profiles are developed and provided. Individual profiles have a precision of order 5% and an estimated accuracy of about 19% at 3 hPa, 14% at 10 hPa, and 26% at 50 hPa. Profile segments within about 2 km of the tropopause are often affected by emissions from clouds that appear in the finite field-of-view of the detector for the LIMS H2O channel. Zonally-averaged distributions of the LIMS V6 H2O are compared with those from the more recent Microwave Limb Sounder (MLS satellite experiment for November, February, and May of 2004/05. The patterns and values of their respective distributions are similar in many respects. Effects of a strengthened Brewer-Dobson circulation are indicated in the MLS distributions of the recent decade versus those of LIMS from 1978/79. A tropical tape recorder signal is present in the 7-month time series of LIMS V6 H2O with lowest values in February 1979, and the estimated, annually-averaged "entry-level" H2O is 3.5 to 3.8 ppmv. It is judged that this historic LIMS water vapor dataset is of good quality for studies of the near global-scale chemistry and transport for pressure levels from 3 hPa to about 70 to 100 hPa.

  1. Final Scientific/Technical Report. A closed path methane and water vapor gas analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Liukang [LI-COR Inc., Lincoln, NE (United States); McDermitt, Dayle [LI-COR Inc., Lincoln, NE (United States); Anderson, Tyler [LI-COR Inc., Lincoln, NE (United States); Riensche, Brad [LI-COR Inc., Lincoln, NE (United States); Komissarov, Anatoly [LI-COR Inc., Lincoln, NE (United States); Howe, Julie [LI-COR Inc., Lincoln, NE (United States)

    2012-02-01

    Robust, economical, low-power and reliable closed-path methane (CH4), carbon dioxide (CO2), and water vapor (H2O) analyzers suitable for long-term measurements are not readily available commercially. Such analyzers are essential for quantifying the amount of CH4 and CO2 released from various ecosystems (wetlands, rice paddies, forests, etc.) and other surface contexts (e.g. landfills, animal husbandry lots, etc.), and for understanding the dynamics of the atmospheric CH4 and CO2 budget and their impact on climate change and global warming. The purpose of this project is to develop a closed-path methane, carbon dioxide gas and water vapor analyzer capable of long-term measurements in remote areas for global climate change and environmental research. The analyzer will be capable of being deployed over a wide range of ecosystems to understand methane and carbon dioxide exchange between the atmosphere and the surface. Measurements of methane and carbon dioxide exchange need to be made all year-round with limited maintenance requirements. During this Phase II effort, we successfully completed the design of the electronics, optical bench, trace gas detection method and mechanical infrastructure. We are using the technologies of two vertical cavity surface emitting lasers, a multiple-pass Herriott optical cell, wavelength modulation spectroscopy and direct absorption to measure methane, carbon dioxide, and water vapor. We also have designed the instrument application software, Field Programmable Gate Array (FPGA), along with partial completion of the embedded software. The optical bench has been tested in a lab setting with very good results. Major sources of optical noise have been identified and through design, the optical noise floor is approaching -60dB. Both laser modules can be temperature controlled to help maximize the stability of the analyzer. Additionally, a piezo electric transducer has been

  2. Large Scale Water Vapor Sources Relative to the October 2000 Piedmont Flood

    Science.gov (United States)

    Turato, Barbara; Reale, Oreste; Siccardi, Franco

    2003-01-01

    Very intense mesoscale or synoptic-scale rainfall events can occasionally be observed in the Mediterranean region without any deep cyclone developing over the areas affected by precipitation. In these perplexing cases the synoptic situation can superficially look similar to cases in which very little precipitation occurs. These situations could possibly baffle the operational weather forecasters. In this article, the major precipitation event that affected Piedmont (Italy) between 13 and 16 October 2000 is investigated. This is one of the cases in which no intense cyclone was observed within the Mediterranean region at any time, only a moderate system was present, and yet exceptional rainfall and flooding occurred. The emphasis of this study is on the moisture origin and transport. Moisture and energy balances are computed on different space- and time-scales, revealing that precipitation exceeds evaporation over an area inclusive of Piedmont and the northwestern Mediterranean region, on a time-scale encompassing the event and about two weeks preceding it. This is suggestive of an important moisture contribution originating from outside the region. A synoptic and dynamic analysis is then performed to outline the potential mechanisms that could have contributed to the large-scale moisture transport. The central part of the work uses a quasi-isentropic water-vapor back trajectory technique. The moisture sources obtained by this technique are compared with the results of the balances and with the synoptic situation, to unveil possible dynamic mechanisms and physical processes involved. It is found that moisture sources on a variety of atmospheric scales contribute to this event. First, an important contribution is caused by the extratropical remnants of former tropical storm Leslie. The large-scale environment related to this system allows a significant amount of moisture to be carried towards Europe. This happens on a time- scale of about 5-15 days preceding the

  3. Interaction of aerosol particles composed of protein and saltswith water vapor: hygroscopic growth and microstructural rearrangement

    Directory of Open Access Journals (Sweden)

    E. Mikhailov

    2004-01-01

    Full Text Available The interaction of aerosol particles composed of the protein bovine serum albumin (BSA and the inorganic salts sodium chloride and ammonium nitrate with water vapor has been investigated by hygroscopicity tandem differential mobility analyzer (H-TDMA experiments complemented by transmission electron microscopy (TEM and Köhler theory calculations (100-300nm particle size range, 298K, 960hPa. BSA was chosen as a well-defined model substance for proteins and other macromolecular compounds, which constitute a large fraction of the water-soluble organic component of air particulate matter. Pure BSA particles exhibited deliquescence and efflorescence transitions at 35% relative humidity ( and a hygroscopic diameter increase by up to 10% at 95% in good agreement with model calculations based on a simple parameterisation of the osmotic coefficient. Pure NaCl particles were converted from near-cubic to near-spherical shape upon interaction with water vapor at relative humidities below the deliquescence threshold (partial surface dissolution and recrystallisation, and the diameters of pure NH4NO3 particles decreased by up to 10% due to chemical decomposition and evaporation. Mixed NaCl-BSA and NH4NO3-BSA particles interacting with water vapor exhibited mobility equivalent diameter reductions of up to 20%, depending on particle generation, conditioning, size, and chemical composition (BSA dry mass fraction 10-90%. These observations can be explained by formation of porous agglomerates (envelope void fractions up to 50% due to ion-protein interactions and electric charge effects on the one hand, and by compaction of the agglomerate structure due to capillary condensation effects on the other. The size of NH4NO3-BSA particles was apparently also influenced by volatilisation of NH4NO3, but not as much as for pure salt particles, i.e. the protein inhibited the decomposition of NH4NO3 or the evaporation of the decomposition products NH3 and HNO3. The

  4. Effect of water vapor treatment on apatite formation on precalcified titanium and bond strength of coatings to substrates.

    Science.gov (United States)

    Feng, B; Chen, Y; Zhang, X D

    2002-01-01

    In previous investigations, a simple method, precalcification, was developed for bioactivating titanium. After a titanium sample was precalcified in a boiling saturated Ca(OH)(2) solution and then immersed in a calcium phosphate supersaturated solution, an apatite coating rapidly precipitated onto its surface. In the present study, heat-treatment in water vapor was carried out prior to precalcification. Heat-treatment in water vapor stimulated the chemical reaction between titanium, calcium, and phosphate. Coating properties were improved, and the bond strength of the coating to substrate was enhanced. Copyright 2001 John Wiley & Sons, Inc.

  5. Analysis of the retention of water vapor on silica gel; Analisis de la retencion del vapor de agua en silica gel

    Energy Technology Data Exchange (ETDEWEB)

    Herranz, M.; Pinilla, J. L.; Alegria, N.; Idoeta, R.; Legarda, F.

    2011-07-01

    Among the various sampling systems tritium content in the atmosphere as water vapor, one of the most basic and, therefore, of widespread use in the environmental field, is the retention on silica gel. However, the behavior of the collection efficiency of silica gel under varying conditions of air temperature and relative humidity makes it difficult to define the amount of this necessary for proper completion of sampling, especially in situations of prolonged sampling. This paper presents partial results obtained in a study on the analysis of these efficiencies under normal conditions of sampling. (Author)

  6. Water Vapor in Titan's Stratosphere from Cassini CIRS Far-Infrared Spectra

    Science.gov (United States)

    Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bezard, B.; hide

    2012-01-01

    Here we report the measurement of water vapor in Titan's stratosphere using the Cassini Composite Infrared Spectrometer (CIRS). CIRS senses water emissions in the far infrared spectral region near 50 micron, which we have modeled using two independent radiative transfer codes. From the analysis of nadir spectra we have derived a mixing ratio of 0.14 +/- 0.05 ppb at an altitude of 97 km, which corresponds to an integrated (from 0 to 600 km) surface normalized column abundance of 3.7 +/- 1.3 1014 molecules/cm2. In the latitude range 80S to 30N we see no evidence for latitudinal variations in these abundances within the error bars. Using limb observations, we obtained mixing ratios of 0.13 +/- 0.04 ppb at an altitude of 115 km and 0.45 +/- 0.15 ppb at an altitude of 230 km, confirming that the water abundance has a positive vertical gradient as predicted by photochemical models. We have also fitted our data using scaling factors of 0.1-0.6 to these photochemical model profiles, indicating that the models over-predict the water abundance in Titan's lower stratosphere.

  7. Increasing vertical resolution of three-dimensional atmospheric water vapor retrievals using a network of scanning compact microwave radiometers

    Science.gov (United States)

    Sahoo, Swaroop

    2011-12-01

    The thermodynamic properties of the troposphere, in particular water vapor content and temperature, change in response to physical mechanisms, including frictional drag, evaporation, transpiration, heat transfer and flow modification due to terrain. The planetary boundary layer (PBL) is characterized by a high rate of change in its thermodynamic state on time scales of typically less than one hour. Large horizontal gradients in vertical wind speed and steep vertical gradients in water vapor and temperature in the PBL are associated with high-impact weather. Observation of these gradients in the PBL with high vertical resolution and accuracy is important for improvement of weather prediction. Satellite remote sensing in the visible, infrared and microwave provide qualitative and quantitative measurements of many atmospheric properties, including cloud cover, precipitation, liquid water content and precipitable water vapor in the upper troposphere. However, the ability to characterize the thermodynamic properties of the PBL is limited by the confounding factors of ground emission in microwave channels and of cloud cover in visible and IR channels. Ground-based microwave radiometers are routinely used to measure thermodynamic profiles. The vertical resolution of such profiles retrieved from radiometric brightness temperatures depends on the number and choice of frequency channels, the scanning strategy and the accuracy of brightness temperature measurements. In the standard technique, which uses brightness temperatures from vertically pointing radiometers, the vertical resolution of the retrieved water vapor profile is similar to or larger than the altitude at which retrievals are performed. This study focuses on the improvement of the vertical resolution of water vapor retrievals by including scanning measurements at a variety of elevation angles. Elevation angle scanning increases the path length of the atmospheric emission, thus improving the signal-to-noise ratio

  8. Reaction rates of Criegee intermediates with water vapor and hydrogen sulfide

    Science.gov (United States)

    Smith, M. C.; Boering, K. A.

    2016-12-01

    Criegee intermediates are byproducts of the reaction of alkenes with ozone. Bimolecular reactions of Criegee intermediates can lead to the production of low-volatility organic compounds and acids in the atmosphere, which in turn play a role in determining the concentration, size, and optical properties of aerosols. Recently, a novel method for producing measurable quantities of stabilized Criegee intermediates in the laboratory paved the way for the development of new experimental techniques to study their chemical properties and predict their importance in the atmosphere. Our lab uses transient UV absorption spectroscopy to measure the formation and decay of Criegee intermediates in a flow cell, using 8-pass absorption of a bright plasma light source combined with sensitive balanced photodiode detection. Here we measured the transient absorption of CH2OO and obtained rate coefficients for its reaction with water dimer from 283 to 324 K. The fast reaction of CH2OO with water dimer is thought to dominate CH2OO removal in the atmosphere, but reaction rates can vary considerably under different conditions of temperature, humidity, and pressure. The rate of the reaction of CH2OO with water dimer was found to exhibit a strong negative temperature dependence. Due to the strong temperature dependence, and shifting competition between water dimer and water monomer (which has a positive temperature dependence), the effective loss rate of CH2OO by reaction with water vapor is highly sensitive to atmospheric conditions. We also present the first measurements of the reaction rate between CH2OO and hydrogen sulfide, which is analogous to the water molecule and may have significance in areas with volcanic activity.

  9. Correcting attenuated total reflection-fourier transform infrared spectra for water vapor and carbon dioxide

    DEFF Research Database (Denmark)

    Bruun, Susanne Wrang; Kohler, Achim; Adt, Isabelle

    2006-01-01

    an absorption band from either water vapor or CO(2). From two calibration data sets, gas model spectra were estimated in each of the four spectral regions, and these model spectra were applied for correction of gas absorptions in two independent test sets (spectra of aqueous solutions and a yeast biofilm (C....... albicans) growing on an ATR crystal, respectively). The amounts of the atmospheric gases as expressed by the model spectra were estimated by regression, using second-derivative transformed spectra, and the estimated gas spectra could subsequently be subtracted from the sample spectra. For spectra...... of the growing yeast biofilm, the gas correction revealed otherwise hidden variations of relevance for modeling the growth dynamics. As the presented method improved the interpretation of the principle component analysis (PCA) models, it has proven to be a valuable tool for filtering atmospheric variation in ATR...

  10. Calculation of the transport and relaxation properties of dilute water vapor

    Science.gov (United States)

    Hellmann, Robert; Bich, Eckard; Vogel, Eckhard; Dickinson, Alan S.; Vesovic, Velisa

    2009-07-01

    Transport properties of dilute water vapor have been calculated in the rigid-rotor approximation using four different potential energy hypersurfaces and the classical-trajectory method. Results are reported for shear viscosity, self-diffusion, thermal conductivity, and volume viscosity in the dilute-gas limit for the temperature range of 250-2500 K. Of these four surfaces the CC-pol surface of Bukowski et al. [J. Chem. Phys. 128, 094314 (2008)] is in best accord with the available measurements. Very good agreement is found with the most accurate results for viscosity in the whole temperature range of the experiments. For thermal conductivity the deviations of the calculated values from the experimental data increase systematically with increasing temperature to around 5% at 1100 K. For both self-diffusion and volume viscosity, the much more limited number of available measurements are generally consistent with the calculated values, apart from the lower temperature isotopically labeled diffusion measurements.

  11. Luminescence of mesoporous silicon powders treated by high-pressure water vapor annealing

    Science.gov (United States)

    Gelloz, Bernard; Loni, Armando; Canham, Leigh; Koshida, Nobuyoshi

    2012-07-01

    We have studied the photoluminescence of nanocrystalline silicon microparticle powders fabricated by fragmentation of PSi membranes. Several porosities were studied. Some powders have been subjected to further chemical etching in HF in order to reduce the size of the silicon skeleton and reach quantum sizes. High-pressure water vapor annealing was then used to enhance both the luminescence efficiency and stability. Two visible emission bands were observed. A red band characteristic of the emission of Si nanocrystals and a blue band related to localized centers in oxidized powders. The blue band included a long-lived component, with a lifetime exceeding 1 sec. Both emission bands depended strongly on the PSi initial porosity. The colors of the processed powders were tunable from brown to off-white, depending on the level of oxidation. The surface area and pore volume of some powders were also measured and discussed. The targeted applications are in cosmetics and medicine.

  12. Transient desorption of water vapor - A potential source of error in upper atmosphere rocket experiments

    Science.gov (United States)

    Kendall, B. R. F.; Weeks, J. O.

    1974-01-01

    Results of measurements of the outgassing rates of samples of materials and surface finishes used on the outer skins of rocket-borne experiment packages in simulated rocket ascents. The results showed outgassing rates for anodized aluminum in the second minute of flight which are two to three orders of magnitude higher than those given in typical tables of outgassing rates. The measured rates for aluminum with chromate conversion surface coatings were also abnormally high. These abnormally high initial rates fell quickly after about five to ten minutes to values comparable with those in the published literature. It is concluded that anodized and chromate conversion coatings on the aluminum outer surfaces of a sounding rocket experiment package will cause gross distortion of the true water vapor environment.

  13. An environmental sample chamber for reliable scanning transmission x-ray microscopy measurements under water vapor

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Stephen T.; Nigge, P.; Prakash, Shruti; Laskin, Alexander; Wang, Bingbing; Tyliszczak, Tolek; Leone, Stephen R.; Gilles, Mary K.

    2013-08-01

    We have designed, fabricated, and tested a compact gas-phase reactor for performing in situ soft x-ray scanning transmission x-ray microscopy (STXM) measurements. The reactor accommodates many gas atmospheres, including reactive or corrosive gasses, but was designed specically to address the needs of measurements under water vapor. An on-board sensor measures the relative humidity and temperature inside the reactor, minimizing uncertainties associated with measuring these quantities outside the instrument. The reactor mounts directly to the existing sample holder used in the majority of STXM instruments around the world and installs with minimal instrument reconguration. Using the reactor contributes over 85% less additional absorption compared to lling the STXM chamber with process gas, and results in much more stable imaging conditions. The reactor is in use at the STXM instruments at beamlines 11.0.2 and 5.3.2.2 at the Advanced Light Source.

  14. Measurement of Turbulent Water Vapor Fluxes from Lightweight Unmanned Aircraft Systems

    Science.gov (United States)

    Thomas, R. M.; Ramanathan, V.; Nguyen, H.; Lehmann*, K.

    2010-12-01

    Scientists at the Center for Clouds, Chemistry and Climate (C4) at the Scripps Institution of Oceanography have successfully used Unmanned Aircraft Systems (UASs) for measurements of radiation fluxes, aerosol concentrations and cloud microphysical properties. Building on this success, a payload to measure water vapor fluxes using the eddy covariance (EC) technique has been recently developed and tested. To our knowledge this is the first UAS turbulent flux system to incorporate high-frequency water vapor measurements. The driving aim of the water vapor flux system’s development is to investigate ‘atmospheric rivers’ in the north-western Pacific Ocean, these can lead to sporadic yet extreme rainfall and flooding events upon landfall in California. Such a flux system may also be used to investigate other weather events (e.g. the formation of hurricanes) and offers a powerful aerosol-cloud-radiative forcing investigative tool when combined with the existing aerosol/radiation and cloud microphysics UAS payloads. The atmospheric vertical wind component (w) is derived by this system at up to 100Hz using data from a GPS/Inertial Measurement Unit (GPS/IMU) combined with a fast-response gust probe mounted on the UAV. Measurements of w are then combined with equally high frequency water vapor data (collected using a Campbell Scientific Krypton Hygrometer) to calculate latent heat fluxes (λE). Two test flights were conducted at the NASA Dryden test facility on 27th May 2010, located in the Mojave Desert. Horizontal flight legs were recorded at four altitudes between 1000-2500 masl within the convective boundary layer. Preliminary data analysis indicates averaged spectral data follow the theoretical -5/3 slope , and extrapolation of the flux profile to the surface resulted in λE of 1.6 W m-2; in good agreement with 1.0 W m-2 λE measured by NOAA from a surface tower using standard flux techniques. The system performance during the Dryden test, as well as subsequent

  15. Major Upgrades to the AIRS Version-6 Water Vapor Profile Methodology

    Science.gov (United States)

    Susskind, Joel; Blaisdell, John; Iredell, Lena; Lee, Jae N.

    2015-01-01

    Additional changes in Version-6.19 include all previous updates made to the q(p) retrieval since Version-6: Modified Neural-Net q0(p) guess above the tropopause Linearly tapers the neural net guess to match climatology at 70 mb, not at the top of the atmosphereChanged the 11 trapezoid q(p) perturbation functions used in Version-6 so as to match the 24 functions used in T(p) retrieval step. These modifications resulted in improved water vapor profiles in Version-6.19 compared to Version-6.Version-6.19 is tested for all of August 2013 and August 2014, as well for select other days. Before finalized and operational in 2016, the V-6.19 can be acquired upon request for limited time intervals.

  16. Radiosonde Sensors Bias in Precipitable Water Vapor From Comparisons With Global Positioning System Measurements

    Directory of Open Access Journals (Sweden)

    Chang-Geun Park

    2012-09-01

    Full Text Available In this study, we compared the precipitable water vapor (PWV data derived from the radiosonde observation data at Sokcho Observatory and the PWV data at Sokcho Global Positioning System (GPS Observatory provided by Korea Astronomy and Space Science Institute, for the years of 2006, 2008, 2010, and analyzed the radiosonde seasonal, diurnal bias according to radiosonde sensor types. In the scatter diagram of the daytime and nighttime radiosonde PWV data and the GPS PWV data, dry bias was found in the daytime radiosonde observation as known in the previous study. Overall, the tendency that the wet bias of the radiosonde PWV increased as the GPS PWV decreased and the dry bias of the radiosonde PWV increased as the GPS PWV increased. The quantitative analysis of the bias and error of the radiosonde PWV data showed that the mean bias decreased in the nighttime except for 2006 winter, and in comparison for summer, RS92-SGP sensor showed the highest quality.

  17. Total column water vapor estimation over land using radiometer data from SAC-D/Aquarius

    Science.gov (United States)

    Epeloa, Javier; Meza, Amalia

    2018-02-01

    The aim of this study is retrieving atmospheric total column water vapor (CWV) over land surfaces using a microwave radiometer (MWR) onboard the Scientific Argentine Satellite (SAC-D/Aquarius). To research this goal, a statistical algorithm is used for the purpose of filtering the study region according to the climate type. A log-linear relationship between the brightness temperatures of the MWR and CWV obtained from Global Navigation Satellite System (GNSS) measurements was used. In this statistical algorithm, the retrieved CWV is derived from the Argentinian radiometer's brightness temperature which works at 23.8 GHz and 36.5 GHz, and taking into account CWVs observed from GNSS stations belonging to a region sharing the same climate type. We support this idea, having found a systematic effect when applying the algorithm; it was generated for one region using the previously mentioned criteria, however, it should be applied to additional regions, especially those with other climate types. The region we analyzed is in the Southeastern United States of America, where the climate type is Cfa (Köppen - Geiger classification); this climate type includes moist subtropical mid-latitude climates, with hot, muggy summers and frequent thunderstorms. However, MWR only contains measurements taken from over ocean surfaces; therefore the determination of water vapor over land is an important contribution to extend the use of the SAC-D/Aquarius radiometer measurements beyond the ocean surface. The CWVs computed by our algorithm are compared against radiosonde CWV observations and show a bias of about -0.6 mm, a root mean square (rms) of about 6 mm and a correlation of 0.89.

  18. MIAWARA-C, a new ground based water vapor radiometer for measurement campaigns

    Directory of Open Access Journals (Sweden)

    C. Straub

    2010-09-01

    Full Text Available In this paper a new 22 GHz water vapor spectro-radiometer which has been specifically designed for profile measurement campaigns of the middle atmosphere is presented. The instrument is of a compact design and has a simple set up procedure. It can be operated as a standalone instrument as it maintains its own weather station and a calibration scheme that does not rely on other instruments or the use of liquid nitrogen. The optical system of MIAWARA-C combines a choked gaussian horn antenna with a parabolic mirror which reduces the size of the instrument in comparison with currently existing radiometers. For the data acquisition a correlation receiver is used together with a digital cross correlating spectrometer. The complete backend section, including the computer, is located in the same housing as the instrument. The receiver section is temperature stabilized to minimize gain fluctuations. Calibration of the instrument is achieved through a balancing scheme with the sky used as the cold load and the tropospheric properties are determined by performing regular tipping curves. Since MIAWARA-C is used in measurement campaigns it is important to be able to determine the elevation pointing in a simple manner as this is a crucial parameter in the calibration process. Here we present two different methods; scanning the sky and the Sun. Finally, we report on the first spectra and retrieved water vapor profiles acquired during the Lapbiat campaign at the Finnish Meteorological Institute Arctic Research Centre in Sodankylä, Finland. The performance of MIAWARA-C is validated here by comparison of the presented profiles against the equivalent profiles from the Microwave Limb Sounder on the EOS/Aura satellite.

  19. Water vapor in the spectrum of the extrasolar planet HD 189733b. I. The transit

    Energy Technology Data Exchange (ETDEWEB)

    McCullough, P. R.; Crouzet, N. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Deming, D. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Madhusudhan, N., E-mail: pmcc@stsci.edu [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States)

    2014-08-10

    We report near-infrared spectroscopy of the gas giant planet HD 189733b in transit. We used the Hubble Space Telescope Wide Field Camera 3 (HST WFC3) with its G141 grism covering 1.1 μm to 1.7 μm and spatially scanned the image across the detector at 2'' s{sup –1}. When smoothed to 75 nm bins, the local maxima of the transit depths in the 1.15 μm and 1.4 μm water vapor features are, respectively, 83 ± 53 ppm and 200 ± 47 ppm greater than the local minimum at 1.3 μm. We compare the WFC3 spectrum with the composite transit spectrum of HD 189733b assembled by Pont et al., extending from 0.3 μm to 24 μm. Although the water vapor features in the WFC3 spectrum are compatible with the model of non-absorbing, Rayleigh-scattering dust in the planetary atmosphere, we also re-interpret the available data with a clear planetary atmosphere. In the latter interpretation, the slope of increasing transit depth with shorter wavelengths from the near infrared, through the visible, and into the ultraviolet is caused by unocculted star spots, with a smaller contribution of Rayleigh scattering by molecular hydrogen in the planet's atmosphere. At relevant pressures along the terminator, our model planetary atmosphere's temperature is ∼700 K, which is below the condensation temperatures of sodium- and potassium-bearing molecules, causing the broad wings of the spectral lines of Na I and K I at 0.589 μm and 0.769 μm to be weak.

  20. Investigation of water adsorption and hygroscopicity of atmospherically relevant particles using a commercial vapor sorption analyzer

    Science.gov (United States)

    Gu, Wenjun; Li, Yongjie; Zhu, Jianxi; Jia, Xiaohong; Lin, Qinhao; Zhang, Guohua; Ding, Xiang; Song, Wei; Bi, Xinhui; Wang, Xinming; Tang, Mingjin

    2017-10-01

    Water adsorption and hygroscopicity are among the most important physicochemical properties of aerosol particles, largely determining their impacts on atmospheric chemistry, radiative forcing, and climate. Measurements of water adsorption and hygroscopicity of nonspherical particles under subsaturated conditions are nontrivial because many widely used techniques require the assumption of particle sphericity. In this work we describe a method to directly quantify water adsorption and mass hygroscopic growth of atmospheric particles for temperature in the range of 5-30 °C, using a commercial vapor sorption analyzer. A detailed description of instrumental configuration and experimental procedures, including relative humidity (RH) calibration, is provided first. It is then demonstrated that for (NH4)2SO4 and NaCl, deliquescence relative humidities and mass hygroscopic growth factors measured using this method show good agreements with experimental and/or theoretical data from literature. To illustrate its ability to measure water uptake by particles with low hygroscopicity, we used this instrument to investigate water adsorption by CaSO4 ṡ 2H2O as a function of RH at 25 °C. The mass hygroscopic growth factor of CaSO4 ṡ 2H2O at 95 % RH, relative to that under dry conditions (RH < 1 %), was determined to be (0.450±0.004) % (1σ). In addition, it is shown that this instrument can reliably measure a relative mass change of 0.025 %. Overall, we have demonstrated that this commercial instrument provides a simple, sensitive, and robust method to investigate water adsorption and hygroscopicity of atmospheric particles.

  1. Analysis of heterogeneous water vapor uptake by metal iodide cluster ions via differential mobility analysis-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Oberreit, Derek [Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Fluid Measurement Technologies, Inc., Saint Paul, Minnesota 55110 (United States); Rawat, Vivek K.; Larriba-Andaluz, Carlos; Ouyang, Hui; McMurry, Peter H.; Hogan, Christopher J., E-mail: hogan108@umn.edu [Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2015-09-14

    The sorption of vapor molecules onto pre-existing nanometer sized clusters is of importance in understanding particle formation and growth in gas phase environments and devising gas phase separation schemes. Here, we apply a differential mobility analyzer-mass spectrometer based approach to observe directly the sorption of vapor molecules onto iodide cluster ions of the form (MI){sub x}M{sup +} (x = 1-13, M = Na, K, Rb, or Cs) in air at 300 K and with water saturation ratios in the 0.01-0.64 range. The extent of vapor sorption is quantified in measurements by the shift in collision cross section (CCS) for each ion. We find that CCS measurements are sensitive enough to detect the transient binding of several vapor molecules to clusters, which shift CCSs by only several percent. At the same time, for the highest saturation ratios examined, we observed CCS shifts of up to 45%. For x < 4, cesium, rubidium, and potassium iodide cluster ions are found to uptake water to a similar extent, while sodium iodide clusters uptake less water. For x ≥ 4, sodium iodide cluster ions uptake proportionally more water vapor than rubidium and potassium iodide cluster ions, while cesium iodide ions exhibit less uptake. Measured CCS shifts are compared to predictions based upon a Kelvin-Thomson-Raoult (KTR) model as well as a Langmuir adsorption model. We find that the Langmuir adsorption model can be fit well to measurements. Meanwhile, KTR predictions deviate from measurements, which suggests that the earliest stages of vapor uptake by nanometer scale species are not well described by the KTR model.

  2. Sensitive limits on the abundance of cold water vapor in the DM Tauri protoplanetary disk

    Science.gov (United States)

    Bergin, E. A.; Hogerheijde, M. R.; Brinch, C.; Fogel, J.; Yıldız, U. A.; Kristensen, L. E.; van Dishoeck, E. F.; Bell, T. A.; Blake, G. A.; Cernicharo, J.; Dominik, C.; Lis, D.; Melnick, G.; Neufeld, D.; Panić, O.; Pearson, J. C.; Bachiller, R.; Baudry, A.; Benedettini, M.; Benz, A. O.; Bjerkeli, P.; Bontemps, S.; Braine, J.; Bruderer, S.; Caselli, P.; Codella, C.; Daniel, F.; di Giorgio, A. M.; Doty, S. D.; Encrenaz, P.; Fich, M.; Fuente, A.; Giannini, T.; Goicoechea, J. R.; de Graauw, Th.; Helmich, F.; Herczeg, G. J.; Herpin, F.; Jacq, T.; Johnstone, D.; Jørgensen, J. K.; Larsson, B.; Liseau, R.; Marseille, M.; McCoey, C.; Nisini, B.; Olberg, M.; Parise, B.; Plume, R.; Risacher, C.; Santiago-García, J.; Saraceno, P.; Shipman, R.; Tafalla, M.; van Kempen, T. A.; Visser, R.; Wampfler, S. F.; Wyrowski, F.; van der Tak, F.; Jellema, W.; Tielens, A. G. G. M.; Hartogh, P.; Stützki, J.; Szczerba, R.

    2010-10-01

    We performed a sensitive search for the ground-state emission lines of ortho- and para-water vapor in the DM Tau protoplanetary disk using the Herschel/HIFI instrument. No strong lines are detected down to 3σ levels in 0.5 km s-1 channels of 4.2 mK for the 110-101 line and 12.6 mK for the 111-000 line. We report a very tentative detection, however, of the 110-101 line in the wide band spectrometer, with a strength of Tmb = 2.7 mK, a width of 5.6 km s-1 and an integrated intensity of 16.0 mK km s-1. The latter constitutes a 6σ detection. Regardless of the reality of this tentative detection, model calculations indicate that our sensitive limits on the line strengths preclude efficient desorption of water in the UV illuminated regions of the disk. We hypothesize that more than 95-99% of the water ice is locked up in coagulated grains that have settled to the midplane. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with participation important from NASA.

  3. Adsorption and solvation of ethanol at the water liquid-vapor interface: a molecular dynamics study

    Science.gov (United States)

    Wilson, M. A.; Pohorille, A.

    1997-01-01

    The free energy profiles of methanol and ethanol at the water liquid-vapor interface at 310K were calculated using molecular dynamics computer simulations. Both alcohols exhibit a pronounced free energy minimum at the interface and, therefore, have positive adsorption at this interface. The surface excess was computed from the Gibbs adsorption isotherm and was found to be in good agreement with experimental results. Neither compound exhibits a free energy barrier between the bulk and the surface adsorbed state. Scattering calculations of ethanol molecules from a gas phase thermal distribution indicate that the mass accommodation coefficient is 0.98, and the molecules become thermalized within 10 ps of striking the interface. It was determined that the formation of the solvation structure around the ethanol molecule at the interface is not the rate-determining step in its uptake into water droplets. The motion of an ethanol molecule in a water lamella was followed for 30 ns. The time evolution of the probability distribution of finding an ethanol molecule that was initially located at the interface is very well described by the diffusion equation on the free energy surface.

  4. Modeling Convective Injection of Water Vapor into the Lower Stratosphere in the Mid-Latitudes over North America

    Science.gov (United States)

    Clapp, C.; Leroy, S. S.; Anderson, J. G.

    2015-12-01

    Water vapor in the upper troposphere and lower stratosphere (UTLS) from the tropics to the poles is important both radiatively and chemically. Water vapor is the most important greenhouse gas, and increases in water vapor concentrations in the UTLS lead to cooling at these levels and induce warming at the surface [Forster and Shine, 1999; 2002;Solomon et al., 2010]. Water vapor is also integral to stratospheric chemistry. It is the dominant source of OH in the lower stratosphere [ Hanisco et al. , 2001], and increases in water vapor concentrations promote stratospheric ozone loss by raising the reactivity of several key heterogeneous reactions as well as by promoting the growth of reactive surface area [Anderson et al., 2012; Carslaw et al., 1995; Carslaw et al., 1997; Drdla and Muller , 2012; Kirk-Davidoff et al., 1999; Shi et al., 2001]. However, the processes that control the distribution and phase of water in this region of the atmosphere are not well understood. This is especially true at mid-latitudes where several different dynamical mechanisms are capable of influencing UTLS water vapor concentrations. The contribution by deep convective storm systems that penetrate into the lower stratosphere is the least well understood and the least well represented in global models because of the small spatial scales and short time scales over which convection occurs. To address this issue, we have begun a modeling study to investigate the convective injection of water vapor from the troposphere into the stratosphere in the mid-latitudes. Fine-scale models have been previously used to simulate convection from the troposphere to the stratosphere [e.g., Homeyer et al., 2014]. Here we employ the Advanced Research Weather and Research Forecasting model (ARW) at 3-km resolution to resolve convection over the eastern United States during August of 2007 and August of 2013. We conduct a comparison of MERRA, the reanalysis used to initialize ARW, and the model output to assess

  5. Treatment of Produced Water Using a Surfactant Modified Zeolite/Vapor Phase Bioreactor System

    Energy Technology Data Exchange (ETDEWEB)

    Lynn E. Katz; Kerry A. Kinney; Robert S. Bowman; Enid J. Sullivan; Soondong Kwon; Elaine B. Darby; Li-Jung Chen; Craig R. Altare

    2006-01-31

    Co-produced water from the oil and gas industry accounts for a significant waste stream in the United States. Produced waters typically contain a high total dissolved solids content, dissolved organic constituents such as benzene and toluene, an oil and grease component as well as chemicals added during the oil-production process. It has been estimated that a total of 14 billion barrels of produced water were generated in 2002 from onshore operations (Veil, 2004). Although much of this produced water is disposed via reinjection, environmental and cost considerations can make surface discharge of this water a more practical means of disposal. In addition, reinjection is not always a feasible option because of geographic, economic, or regulatory considerations. In these situations, it may be desirable, and often necessary from a regulatory viewpoint, to treat produced water before discharge. It may also be feasible to treat waters that slightly exceed regulatory limits for re-use in arid or drought-prone areas, rather than losing them to reinjection. A previous project conducted under DOE Contract DE-AC26-99BC15221 demonstrated that surfactant modified zeolite (SMZ) represents a potential treatment technology for produced water containing BTEX. Laboratory and field experiments suggest that: (1) sorption of benzene, toluene, ethylbenzene and xylenes (BTEX) to SMZ follows linear isotherms in which sorption increases with increasing solute hydrophobicity; (2) the presence of high salt concentrations substantially increases the capacity of the SMZ for BTEX; (3) competitive sorption among the BTEX compounds is negligible; and, (4) complete recovery of the SMZ sorption capacity for BTEX can be achieved by air sparging the SMZ. This report summarizes research for a follow on project to optimize the regeneration process for multiple sorption/regeneration cycles, and to develop and incorporate a vapor phase bioreactor (VPB) system for treatment of the off-gas generated during

  6. Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

    Science.gov (United States)

    Kern, Christoph; Masias, Pablo; Apaza, Fredy; Reath, Kevin; Platt, Ulrich

    2017-01-01

    Water (H2O) is by far the most abundant volcanic volatile species and plays a predominant role in driving volcanic eruptions. However, numerous difficulties associated with making accurate measurements of water vapor in volcanic plumes have limited their use as a diagnostic tool. Here we present the first detection of water vapor in a volcanic plume using passive visible-light differential optical absorption spectroscopy (DOAS). Ultraviolet and visible-light DOAS measurements were made on 21 May 2016 at Sabancaya Volcano, Peru. We find that Sabancaya's plume contained an exceptionally high relative water vapor abundance 6 months prior to its November 2016 eruption. Our measurements yielded average sulfur dioxide (SO2) emission rates of 800–900 t/d, H2O emission rates of around 250,000 t/d, and an H2O/SO2 molecular ratio of 1000 which is about an order of magnitude larger than typically found in high-temperature volcanic gases. We attribute the high water vapor emissions to a boiling-off of Sabancaya's hydrothermal system caused by intrusion of magma to shallow depths. This hypothesis is supported by a significant increase in the thermal output of the volcanic edifice detected in infrared satellite imagery leading up to and after our measurements. Though the measurement conditions encountered at Sabancaya were very favorable for our experiment, we show that visible-light DOAS systems could be used to measure water vapor emissions at numerous other high-elevation volcanoes. Such measurements would provide observatories with additional information particularly useful for forecasting eruptions at volcanoes harboring significant hydrothermal systems.

  7. Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

    Science.gov (United States)

    Kern, Christoph; Masias, Pablo; Apaza, Fredy; Reath, Kevin A.; Platt, Ulrich

    2017-05-01

    Water (H2O) is by far the most abundant volcanic volatile species and plays a predominant role in driving volcanic eruptions. However, numerous difficulties associated with making accurate measurements of water vapor in volcanic plumes have limited their use as a diagnostic tool. Here we present the first detection of water vapor in a volcanic plume using passive visible-light differential optical absorption spectroscopy (DOAS). Ultraviolet and visible-light DOAS measurements were made on 21 May 2016 at Sabancaya Volcano, Peru. We find that Sabancaya's plume contained an exceptionally high relative water vapor abundance 6 months prior to its November 2016 eruption. Our measurements yielded average sulfur dioxide (SO2) emission rates of 800-900 t/d, H2O emission rates of around 250,000 t/d, and an H2O/SO2 molecular ratio of 1000 which is about an order of magnitude larger than typically found in high-temperature volcanic gases. We attribute the high water vapor emissions to a boiling-off of Sabancaya's hydrothermal system caused by intrusion of magma to shallow depths. This hypothesis is supported by a significant increase in the thermal output of the volcanic edifice detected in infrared satellite imagery leading up to and after our measurements. Though the measurement conditions encountered at Sabancaya were very favorable for our experiment, we show that visible-light DOAS systems could be used to measure water vapor emissions at numerous other high-elevation volcanoes. Such measurements would provide observatories with additional information particularly useful for forecasting eruptions at volcanoes harboring significant hydrothermal systems.

  8. Liquid-vapor equilibrium in systems which include paraffins, naphthenes, olefins, benzene, N-methylpyrrolidone, and water

    Energy Technology Data Exchange (ETDEWEB)

    Miroshnichenko, A.A.

    1983-07-20

    The selection of efficient separating agents for the extractive fractionation of aliphatic-aromatic hydrocarbon systems has fundamental importance in technology of preparing pure aromatic hydrocarbons. It has been shown previously that N-methylpyrrolidone (NMP) can be used as an efficient separating agent for paraffin-aromatic hydrocarbon, naphthene-aromatic hydrocarbon, or olefin-aromatic hydrocarbon systems. It was previously shown that the presence of water in the NMP increases its selectivity in the heptane-benzene system. However, the limited number of systems studied which contain heptane does not allow one to make a judgment about the relative volatility of paraffins, naphthenes, olefins, and benzene in mixtures with NMP containing water. Moreover, the complexity of the indicated systems causes definite difficulties in the experimental study of the isobaric liquid-vapor equilbrium for determining the relative volatility ..cap alpha../sub i-j/ of nonaromatic hydrocarbons, i, and benzene, j, as a function of the concentration of an extractant containing water, X/sub r/. The author has previously made studies of methods of calculating liquid-vapor equilibrium in the analogous systems with anhydrous NMP from a limited amount of information about liquid-vapor equilibrium. Therefore the objective of this work was to perform analytical calculations and an experimental check of liquid-vapor equilibrium in systems which included paraffins, naphthenes, olefins, benzene, NMP, and water.

  9. MLS/Aura Near-Real-Time L2 Water Vapor (H2O) Mixing Ratio V003

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2CO_NRT is the EOS Aura Microwave Limb Sounder (MLS) Near-Real-Time (NRT) product for water vapor (H2O). This product contains daily H2O profiles taken from the...

  10. Kinetic Requirements for the Measurement of Mesospheric Water Vapor at 6.8 (microns) under Non-LTE Conditions

    Science.gov (United States)

    Zhou, Daniel K.; Mlynczak, Martin G.; Lopez-Puertas, Manuel; Russell, James M., III

    1999-01-01

    We present accuracy requirements for specific kinetic parameters used to calculate the populations and vibrational temperatures of the H2O(010) and H2O(020) states in the terrestrial mesosphere. The requirements are based on rigorous simulations of the retrieval of mesospheric water vapor profiles from measurements of water vapor infrared emission made by limb scanning instruments on orbiting satellites. Major improvements in the rate constants that describe vibration-to- vibration exchange between the H2O(010) and 02(1) states are required in addition to improved specification of the rate of quenching Of O2(1) by atomic oxygen (0). It is also necessary to more accurately determine the yield of vibrationally excited O2(l) resulting from ozone photolysis. A contemporary measurement of the rate of quenching of H2O(010) by N2 and O2 is also desirable. These rates are either highly uncertain or have never before been measured at atmospheric temperatures. The suggested improvements are necessary for the interpretation of water vapor emission measurements at 6.8 microns to be made from a new spaceflight experiment in less than 2 years. The approach to retrieving water vapor under non-LTE conditions is also presented.

  11. Surfactat’s Impact on the Evaporation Intensity and a Vapor Embryos Generation Kinetics within the Water Droplets

    Science.gov (United States)

    Anisimov, M. P.; Terekhov, V. I.; Shishkin, N. E.

    2017-09-01

    The research of water-surfactant droplets evaporation was provided. The sodium dodecylsulfate was taken as a surfactant (SAS). The initial SAS mass contain was ~ 0,15%. Water and water-surfactant solution droplets were evaporated under the dry air flow blowing at temperatures T0 ~ (20 ÷ 90)0C and air linear velocity VO ~ 2 ÷ 5 m/s. The droplet initial diameter (d0) was equal to ~ 2 mm, Reynolds number was within the interval of Re = 500 ÷ 2000. The droplet evaporation rate and their surface temperature were measured by an Infrared Microscope. The measurements display that the temperature heterogeneity on the droplet surface is initiated by the vapor fluctuating bursts at the local centers. A surfactant admixture into the base liquid (water) has a considerable impact on the vapor centre generation kinetics as well as on the time behavior of the droplets evaporating surfaces. The environmental conditions have the weak impact on the vapor formation, but the inner conditions, i.e. droplet’s temperature and pressure in it and physical properties of the base liquid have the considerable impact on the vapor generation kinetics. A surfactant adding makes surface tension higher. That depresses a heat-mass transfer and rises an average temperature of droplets.

  12. Forward modeling and retrieval of water vapor from the Global Ozone Monitoring Experiment: Treatment of narrowband absorption spectra

    NARCIS (Netherlands)

    Lang, R.; Maurellis, A.N.; van der Zande, W.J.; Aben, I.; Landgraf, J.; Ubachs, W.M.G.

    2002-01-01

    [1] We present the algorithm and results for a new fast forward modeling technique applied to the retrieval of atmospheric water vapor from satellite measurements using a weak ro-vibrational overtone band in the visible. The algorithm uses an Optical Absorption Coefficient Spectroscopy (OACS) method

  13. Profiling water vapor mixing ratios in Finland by means of a Raman lidar, a satellite and a model

    Science.gov (United States)

    Filioglou, Maria; Nikandrova, Anna; Niemelä, Sami; Baars, Holger; Mielonen, Tero; Leskinen, Ari; Brus, David; Romakkaniemi, Sami; Giannakaki, Elina; Komppula, Mika

    2017-11-01

    We present tropospheric water vapor profiles measured with a Raman lidar during three field campaigns held in Finland. Co-located radio soundings are available throughout the period for the calibration of the lidar signals. We investigate the possibility of calibrating the lidar water vapor profiles in the absence of co-existing on-site soundings using water vapor profiles from the combined Advanced InfraRed Sounder (AIRS) and the Advanced Microwave Sounding Unit (AMSU) satellite product; the Aire Limitée Adaptation dynamique Développement INternational and High Resolution Limited Area Model (ALADIN/HIRLAM) numerical weather prediction (NWP) system, and the nearest radio sounding station located 100 km away from the lidar site (only for the permanent location of the lidar). The uncertainties of the calibration factor derived from the soundings, the satellite and the model data are change in disagreement between the lidar and the model has been studied. The analysis showed that, on average, the model underestimates water vapor mixing ratios at high altitudes during spring and summer.

  14. Long-Term Measurement for Low-Tropospheric Water Vapor and Aerosol by Raman Lidar in Wuhan

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2015-04-01

    Full Text Available A Raman Lidar (RL system is developed to measure the water vapor mixing ratio (WVMR and aerosol optical property in Wuhan with high temporal-spatial resolution during rainless nights. The principle of the self-developed lidar system and data processing method are discussed. WVMR profiles of a representative case retrieved by RL, Radiosonde (RS, and microwave radiometer (MR are in good agreement. The relationship of WVMR and aerosol optical depth (AOD indicates that water vapor dramatically reduces with the decline of the AOD. Moreover, the mean relative difference of mean WVMRs at low-troposphere obtained by RL and RS (MR is about 5.17% (9.47% during the analyzed year. The agreement certifies that the self-developed RL system can stably provide accurate and high temporal-spatial resolution data for the fundamental physical studies on water vapor. Furthermore, the maximum AOD from 0.5 km to 3 km is 0.41 at night in spring, which indicates that the air quality in Wuhan is heavily influenced by aerosols that are transported by air mass from the north during this time. Moreover, abundant rainfall led to relatively low AOD in summer (0.22, which demonstrates that water vapor is crucial for air purification.

  15. Experimental study of heat transfer during pseudo-dropwise condensation of water-ethanol and water-isopropanol vapor mixtures on a vertical tube

    Science.gov (United States)

    Chindyakov, A. A.; Smirnov, Yu B.; Vinogradov, A. A.; Mikhailova, E. V.

    2017-11-01

    In the present study experimental heat transfer data on condensation of almost immobile water-ethanol and water-isopropanol vapor mixtures on the vertical smooth copper tube 100 mm long with an outer diameter of 12.0 mm were obtained. Experiments for water-ethanol mixture were carried out at mass concentrations of ethanol from 0.4 to 16% in the vapor phase, and for a water-isopropanol mixture - from 0.6 to 8.4%. The pressure was 0.12…0.13 MPa, vapor-to-surface temperature difference varied from 2 to 40K. The experimental data are represented as dependency of heat transfer coefficient and heat flux on the vapor-to-surface temperature difference. The results of high-speed photography of the condensation process are discussed. It is noted that the transition from film mode to pseudo-dropwise condensation occurs when vapor-to-surface temperature difference is close to dew point - bubble point temperature difference for a given composition of the mixture. According to experimental data, the diffusion thermal resistance and thermal resistance of the liquid phase at different concentrations of the mixture were calculated.

  16. Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

    CERN Document Server

    Makarieva, A M; Sheil, D; Nobre, A D; Li, B -L

    2010-01-01

    Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from the fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 deg C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the...

  17. MODIS/Aqua Near Real Time (NRT) Total Precipitable Water Vapor 5-Min L2 Swath 1km and 5km

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODIS level-2 atmospheric precipitable water product consists of total atmospheric column water vapor amounts (and ancillary parameters) over clear land areas of...

  18. Plasma Kinetics in Electrical Discharge in Mixture of Air, Water and Ethanol Vapors for Hydrogen Enriched Syngas Production

    OpenAIRE

    Shchedrin, A. I.; Levko, D. S.; Ryabtsev, A. V.; Chernyak, V. Ya.; Yukhymenko, V. V.; Olszewski, S. V.; Naumov, V. V.; Prysiazhnevych, I. V.; Solomenko, E. V.; Demchina, V. P.; Kudryavtsev, V. S.

    2008-01-01

    The complex theoretical and experimental investigation of plasma kinetics of the electric discharge in the mixture of air and ethanol-water vapors is carried out. The discharge was burning in the cavity, formed by air jets pumping between electrodes, placed in aqueous ethanol solution. It is found out that the hydrogen yield from the discharge is maximal in the case when ethanol and water in the solution are in equal amounts. It is shown that the hydrogen production increases with the dischar...

  19. Effects of the Shuttle Orbiter fuselage and elevon on the molecular distribution of water vapor from the flash evaporator system

    Science.gov (United States)

    Richmond, R. G.; Kelso, R. M.

    1980-01-01

    A concern has arisen regarding the emissive distribution of water molecules from the shuttle orbiter flash evaporator system (FES). The role of the orbiter fuselage and elevon in affecting molecular scattering distributions was nuclear. The effect of these components were evaluated. Molecular distributions of the water vapor effluents from the FE were measured. These data were compared with analytically predicted values and the resulting implications were calculated.

  20. Measuring Total Column Water Vapor by Pointing an Infrared Thermometer at the Sky

    Science.gov (United States)

    Mims, Forrest M., III; Chambers, Lin H.; Brooks, David R.

    2011-01-01

    A 2-year study affirms that the temperature (Tz) indicated by an inexpensive ($20 to $60) IR thermometer pointed at the cloud-free zenith sky provides an approximate indication of the total column water vapor (precipitable water or PW). PW was measured by a MICROTOPS II sun photometer. The coefficient of correlation (r2) of the PW and Tz was 0.90, and the rms difference was 3.2 mm. A comparison of the Tz data with the PW provided by a GPS site 31 km NNE yielded an r2 of 0.79, and an rms difference of 5.8 mm. An expanded study compared Tz from eight IR thermometers with PW at various times during the day and night from 17 May to 18 October 2010, mainly at the Texas site and 10 days at Hawaii's Mauna Loa Observatory (MLO). The best results of this comparison were provided by two IR thermometers models that yielded an r2 of 0.96 and an rms difference with the PW of 2.7 mm. The results of both the ongoing 2-year study and the 5-month instrument comparison show that IR thermometers can measure PW with an accuracy (rms difference/mean PW) approaching 10%, the accuracy typically ascribed to sun photometers.

  1. The Water Vapor Linestrengths between 11 600 and 12 750 cm-1

    Science.gov (United States)

    Flaud; Camy-Peyret; Bykov; Naumenko; Petrova; Scherbakov; Sinitsa

    1997-10-01

    The water vapor linestrengths in the region of the 3nu + delta resonance polyad of interacting vibrational states (the corresponding upper states are (310), (211), (112), (013), (131), (230), (032), and (051)) have been analyzed leading to accurate dipole moment transition parameters. The effective rotational Hamiltonian constants used to calculate the vibration-rotation wavefunctions (J.-M. Flaud, C. Camy-Peyret, A. Bykov, O. Naumenko, T. Petrova, A. Scherbakov, L. Sinitsa, 1994. J. Mol. Spectrosc. 183, 300-309) take into account both strong centrifugal distortion effects and dark states presence. These effects are known to be important for the highly excited vibrational states of water-like molecules. The input data set included the line intensities measured by Toth (R. Toth, 1994. J. Mol. Spectrosc. 166, 176-183) and the line intensities of the weak bands 2nu1 + 3nu2, 3nu2 + 2nu3, and 3nu1 + nu2 derived from peak absorptions of a spectrum recorded at a pressure of 17.0 Torr and a path length of 434 m. The parameters of the effective dipole moment operator determined by least square fitting give a very satisfactory agreement with experimental values since the mean error for the 876 experimental linestrengths is only 3.9%. It is worth noticing that such an agreement could be reached only because high-order resonance couplings with dark states were explicitly taken into account. Copyright 1997 Academic Press. Copyright 1997Academic Press

  2. NEAR-IR DIRECT DETECTION OF WATER VAPOR IN TAU BOÖTIS b

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, Alexandra C.; Johnson, John A.; Blake, Geoffrey A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Bender, Chad F.; Richert, Alexander J. W. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Carr, John S. [Naval Research Laboratory, Washington, DC 20375 (United States); Barman, Travis, E-mail: alock@caltech.edu [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2014-03-10

    We use high dynamic range, high-resolution L-band spectroscopy to measure the radial velocity (RV) variations of the hot Jupiter in the τ Boötis planetary system. The detection of an exoplanet by the shift in the stellar spectrum alone provides a measure of the planet's minimum mass, with the true mass degenerate with the unknown orbital inclination. Treating the τ Boo system as a high flux ratio double-lined spectroscopic binary permits the direct measurement of the planet's true mass as well as its atmospheric properties. After removing telluric absorption and cross-correlating with a model planetary spectrum dominated by water opacity, we measure a 6σ detection of the planet at K{sub p} = 111 ± 5 km s{sup –1}, with a 1σ upper limit on the spectroscopic flux ratio of 10{sup –4}. This RV leads to a planetary orbital inclination of i=45{sub −4}{sup +3}° and a mass of M{sub P}=5.90{sub −0.20}{sup +0.35} M{sub Jup}. We report the first detection of water vapor in the atmosphere of a non-transiting hot Jupiter, τ Boo b.

  3. GPS water vapor and its comparison with radiosonde and ERA-Interim data in Algeria

    Science.gov (United States)

    Namaoui, Houaria; Kahlouche, Salem; Belbachir, Ahmed Hafid; Van Malderen, Roeland; Brenot, Hugues; Pottiaux, Eric

    2017-05-01

    Remote sensing of atmospheric water vapor using global positioning system (GPS) data has become an effective tool in meteorology, weather forecasting and climate research. This paper presents the estimation of precipitable water (PW) from GPS observations and meteorological data in Algeria, over three stations located at Algiers, Bechar and Tamanrasset. The objective of this study is to analyze the sensitivity of the GPS PW estimates for the three sites to the weighted mean temperature ( T m), obtained separately from two types of T m- T s regression [one general, and one developed specifically for Algeria ( T s stands for surface temperature)], and calculated directly from ERA-Interim data. The results show that the differences in T m are of the order of 18 K, producing differences of 2.01 mm in the final evaluation of PW. A good agreement is found between GPS-PW and PW calculated from radiosondes, with a small mean difference with Vaisala radiosondes. A comparison between GPS and ERA-Interim shows a large difference (4 mm) in the highlands region. This difference is possibly due to the topography. These first results are encouraging, in particular for meteorological applications in this region, with good hope to extend our dataset analysis to a more complete, nationwide coverage over Algeria.

  4. Hydrogen production in a radio-frequency plasma source operating on water vapor

    Science.gov (United States)

    Nguyen, Son-Ca Viet Thi

    The global energy and climate challenges have motivated development of innovative techniques to satisfy energy demand while minimizing emissions. To this end, hydrogen as an alternative energy carrier in the transportation sector is an attractive option. In addition, there is already a great need for hydrogen gas in several industrial processes such as hydro-cracking of crude oil to produce gasoline and production of ammonia and methanol. The current dominant methods of hydrogen production from fossil fuels are well-developed and have reached relatively high energy efficiencies (up to 85%), but these methods rely on non-renewable natural resources and produce carbon dioxide emissions. This work investigates the feasibility of hydrogen production by dissociating water molecules in a radio-frequency (RF) plasma discharge. In addition to the widespread usage of hydrogen gas, applications of water plasma have permeated in many areas of research, and information on basic behaviors of a water plasma discharge will provide fruitful insights for other researchers. An RF plasma source equipped with a double-helix antenna (m = 1 mode) and an applied axial magnetic field is designed to operate on water vapor. It is shown that water molecules are being dissociated in the discharge. Experimental results show that the rate of hydrogen production increases linearly with RF power in the absence of the applied axial magnetic field. With the magnetic field, the rate of hydrogen production increases from 250 to 500 W, and begins to saturate with RF power. Despite this saturation, it is shown that hydrogen increases with magnetic field strength at a fixed RF power. Further, the rate of hydrogen production increases with water input flow rate up to 100 sccm for a fixed RF power level, and begins to decrease at 125 sccm. This dissertation characterizes the rate of hydrogen production and plasma properties as a function of RF power, applied B-field strength, and water input flow rate. A

  5. Heat transfer during pseudo-dropwise condensation of water-ethanol vapor mixture on horizontal finned tubes

    Science.gov (United States)

    Chindyakov, A. A.; Smirnov, Yu B.; Mikhailova, E. V.

    2017-11-01

    In the present work experimental data on heat transfer are obtained for the condensation of almost immobile pure steam and water-ethanol vapor mixture on three copper horizontal finned tubes with a cooled length of 100 mm. The fins are rectangular in shape, their height and thickness are 1 mm, and the spacing between fins 1.3, 2.0 and 3.0 mm. The experiments were carried out at pressures of 0.12…0.15 MPa, the vapor-to-surface temperature difference varied from 5 to 35 K. The mass concentration of ethanol in the vapor phase varied from 8.7 to 14.5%. The experimental data are presented in the form of the dependences of heat transfer coefficient on the vapor-to-wall temperature difference. The heat transfer coefficients for the condensation of pure steam are in good agreement with the calculations by the method of Srinivasan et al. According to experimental data for the condensation of the vapor mixture, diffusion thermal resistance and thermal resistance of the liquid phase at various ethanol concentrations and the spacing between fins were calculated.

  6. Effect of tropospheric models on derived precipitable water vapor over Southeast Asia

    Science.gov (United States)

    Rahimi, Zhoobin; Mohd Shafri, Helmi Zulhaidi; Othman, Faridah; Norman, Masayu

    2017-05-01

    An interesting subject in the field of GPS technology is estimating variation of precipitable water vapor (PWV). This estimation can be used as a data source to assess and monitor rapid changes in meteorological conditions. So far, numerous GPS stations are distributed across the world and the number of GPS networks is increasing. Despite these developments, a challenging aspect of estimating PWV through GPS networks is the need of tropospheric parameters such as temperature, pressure, and relative humidity (Liu et al., 2015). To estimate the tropospheric parameters, global pressure temperature (GPT) model developed by Boehm et al. (2007) is widely used in geodetic analysis for GPS observations. To improve the accuracy, Lagler et al. (2013) introduced GPT2 model by adding annual and semi-annual variation effects to GPT model. Furthermore, Boehm et al. (2015) proposed the GPT2 wet (GPT2w) model which uses water vapor pressure to improve the calculations. The global accuracy of GPT2 and GPT2w models has been evaluated by previous researches (Fund et al., 2011; Munekane and Boehm, 2010); however, investigations to assess the accuracy of global tropospheric models in tropical regions such as Southeast Asia is not sufficient. This study tests and examines the accuracy of GPT2w as one of the most recent versions of tropospheric models (Boehm et al., 2015). We developed a new regional model called Malaysian Pressure Temperature (MPT) model, and compared this model with GPT2w model. The compared results at one international GNSS service (IGS) station located in the south of Peninsula Malaysia shows that MPT model has a better performance than GPT2w model to produce PWV during monsoon season. According to the results, MPT has improved the accuracy of estimated pressure and temperature by 30% and 10%, respectively, in comparison with GPT2w model. These results indicate that MPT model can be a good alternative tool in the absence of meteorological sensors at GPS stations in

  7. Vapor-Liquid Equilibria of Imidazolium Ionic Liquids with Cyano Containing Anions with Water and Ethanol.

    Science.gov (United States)

    Khan, Imran; Batista, Marta L S; Carvalho, Pedro J; Santos, Luís M N B F; Gomes, José R B; Coutinho, João A P

    2015-08-13

    Isobaric vapor-liquid equilibria of 1-butyl-3-methylimidazolium thiocyanate ([C4C1im][SCN]), 1-butyl-3-methylimidazolium dicyanamide ([C4C1im][N(CN)2]), 1-butyl-3-methylimidazolium tricyanomethanide ([C4C1im][C(CN)3]), and 1-ethyl-3-methylimidazolium tetracyanoborate ([C2C1im][B(CN)4]), with water and ethanol were measured over the whole concentration range at 0.1, 0.07, and 0.05 MPa. Activity coefficients were estimated from the boiling temperatures of the binary systems, and the data were used to evaluate the ability of COSMO-RS for describing these molecular systems. Aiming at further understanding the molecular interactions on these systems, molecular dynamics (MD) simulations were performed. On the basis of the interpretation of the radial and spatial distribution functions along with coordination numbers obtained through MD simulations, the effect of the increase of CN-groups in the IL anion in its capability to establish hydrogen bonds with water and ethanol was evaluated. The results obtained suggest that, for both water and ethanol systems, the anion [N(CN)2](-) presents the higher ability to establish favorable interactions due to its charge, and that the ability of the anions to interact with the solvent, decreases with further increasing of the number of cyano groups in the anion. The ordering of the partial charges in the nitrogen atoms from the CN-groups in the anions agrees with the ordering obtained for VLE and activity coefficient data.

  8. New Insights into the Structure of the Vapor/Water Interface from Large-Scale First-Principles Simulations.

    Science.gov (United States)

    Kühne, Thomas D; Pascal, Tod A; Kaxiras, Efthimios; Jung, Yousung

    2011-01-20

    We present extensive ab initio simulations of the molecular arrangements at the vapor/water interface, which provide valuable insights into the interface structure. In particular, the simulations address the controversy of whether there is a significant amount of nondonor configurations at this prototypical interface, using a novel Car-Parrinello-like ab initio molecular dynamics approach. The interface is modeled by a system of 384 water molecules for 125 ps in a two-dimensional periodic slab, the most extensive ab initio molecular dynamics simulation to date. In contrast to previous theoretical simulations and X-ray absorption spectroscopy, but consistent with sum-frequency generation experiments, we observe no evidence for a significant occurrence of acceptor-only species at the vapor/water interface. Besides a distinct surface relaxation effect, we find that only the topmost layers of the interface obey structural order.

  9. Improvements to water vapor transmission and capillary absorption measurements in porous materials

    Science.gov (United States)

    Samuel L. Zelinka; Samuel V. Glass; Charles R. Boardman

    2016-01-01

    The vapor permeability (or equivalently the vapor diffusion resistance factor) and the capillary absorption coefficient are frequently used as inputs to hygrothermal or heat, air, and moisture (HAM) models. However, it has been well documented that the methods used to determine these properties are sensitive to the operator, and wide variations in the properties have...

  10. Evaluation of tunable diode laser absorption spectroscopy for in-process water vapor mass flux measurements during freeze drying.

    Science.gov (United States)

    Gieseler, Henning; Kessler, William J; Finson, Michael; Davis, Steven J; Mulhall, Phillip A; Bons, Vincent; Debo, David J; Pikal, Michael J

    2007-07-01

    The goal of this work was to demonstrate the use of Tunable Diode Laser Absorption Spectroscopy (TDLAS) as a noninvasive method to continuously measure the water vapor concentration and the vapor flow velocity in the spool connecting a freeze-dryer chamber and condenser. The instantaneous measurements were used to determine the water vapor mass flow rate (g/s). The mass flow determinations provided a continuous measurement of the total amount of water removed. Full load runs of pure water at different pressure and shelf temperature settings and a 5% (w/w) mannitol product run were performed in both laboratory and pilot scale freeze dryers. The ratio of "gravimetric/TDLAS" measurements of water removed was 1.02 +/- 0.06. A theoretical heat transfer model was used to predict the mass flow rate and the model results were compared to both the gravimetric and TDLAS data. Good agreement was also observed in the "gravimetric/TDLAS" ratio for the 5% mannitol runs dried in both freeze dryers. The endpoints of primary and secondary drying for the product runs were clearly identified. Comparison of the velocity and mass flux profiles between the laboratory and pilot dryers indicated a higher restriction to mass flow for the lab scale freeze dryer. Copyright 2007 Wiley-Liss, Inc.

  11. Biophysical controls on carbon and water vapor fluxes across a grassland climatic gradient in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Wagle, Pradeep; Xiao, Xiangming; Scott, Russell L.; Kolb, Thomas E.; Cook, David R.; Brunsell, Nathaniel; Baldocchi, Dennis D.; Basara, Jeffrey; Matamala, Roser; Zhou, Yuting; Bajgain, Rajen

    2015-12-01

    Understanding of the underlying causes of spatial variation in exchange of carbon and water vapor fluxes between grasslands and the atmosphere is crucial for accurate estimates of regional and global carbon and water budgets, and for predicting the impact of climate change on biosphere–atmosphere feedbacks of grasslands. We used ground-based eddy flux and meteorological data, and the Moderate Resolution Imaging Spectroradiometer (MODIS) enhanced vegetation index (EVI) from 12 grasslands across the United States to examine the spatial variability in carbon and water vapor fluxes and to evaluate the biophysical controls on the spatial patterns of fluxes. Precipitation was strongly associated with spatial and temporal variability in carbon and water vapor fluxes and vegetation productivity. Grasslands with annual average precipitation <600 mm generally had neutral annual carbon balance or emitted small amount of carbon to the atmosphere. Despite strong coupling between gross primary production (GPP)and evapotranspiration (ET) across study sites, GPP showed larger spatial variation than ET, and EVI had a greater effect on GPP than on ET. Consequently, large spatial variation in ecosystem water use efficiency (EWUE = annual GPP/ET; varying from 0.67 ± 0.55 to 2.52 ± 0.52 g C mm⁻¹ET) was observed. Greater reduction in GPP than ET at high air temperature and vapor pressure deficit caused a reduction in EWUE in dry years, indicating a response which is opposite than what has been reported for forests. Our results show that spatial and temporal variations in ecosystem carbon uptake, ET, and water use efficiency of grasslands were strongly associated with canopy greenness and coverage, as indicated by EVI.

  12. Water vapor in the middle atmosphere of Mars during the 2007 global dust storm

    Science.gov (United States)

    Fedorova, Anna; Bertaux, Jean-Loup; Betsis, Daria; Montmessin, Franck; Korablev, Oleg; Maltagliati, Luca; Clarke, John

    2018-01-01

    Recent observations of the Martian hydrogen corona in the UV H Ly-alpha emission by the Hubble Space Telescope (HST) (Clarke et al., 2014) and the SPICAM UV spectrometer on Mars Express (Chaffin et al., 2014) reported its rapid change by an order of magnitude over a short few months period in 2007 (MY28), which is inconsistent with the existing models. One proposed explanation of the observed increase of the coronal emission is that during the global dust storm water vapor from the lower atmosphere can be transported to higher altitudes, where its photodissociation rate by near-UV sunlight increases, providing an additional source of hydrogen for the upper atmosphere. In this work we study the water vapor vertical distribution in the middle atmosphere of Mars during the 2007 global dust storm based on solar occultation measurements by the SPICAM IR spectrometer onboard the Mars-Express spacecraft. The vertical profiles of H2O density and mixing ratio have been obtained for solar longitudes Ls = 255°-300° in MY28. In the Northern hemisphere from Ls = 268° to Ls = 285° the H2O density at altitudes of 60-80 km increased by an order of magnitude. During the dust storm the profiles extended up to 80 km, with an H2O density exceeding 1010 molecules/cm3 (mixing ratio ≥200 ppm). Two maxima of the H2O density were detected. The largest H2O densities observed at latitudes higher than 60°N, over Ls = 269°-275°, do not directly correlate with the aerosol loading and likely relate to the downwelling branch of the meridional circulation that was intensified during the dust storm, and transported water from the Southern hemisphere to high northern latitudes. The second smaller maximum coincides with the high dust loading at middle northern latitudes. The comparison with geographically close observations in the quiet Mars year MY32, when the H2O content in the Northern hemisphere did not exceed 2 × 1010 molecules/cm3 and 50 ppm at 60 km, showed that the global dust storm

  13. [A novel vapor dynamic headspace enrichment equipment for nontarget screening of volatile organic compounds in drinking water].

    Science.gov (United States)

    Ma, Huilian; Zhang, Haijun; Tian, Yuzeng; Wang, Longxing; Chen, Jiping

    2011-09-01

    A novel vapor dynamic headspace enrichment device was set up for nontarget screening of volatile organic compounds (VOCs) in drinking water. The main operating parameters of this device, such as length of distillation tube, volume of collected condensate, and choice of absorbent, were optimized. In this device, vapor was utilized as a purge gas and water was utilized as a absorbent. With the help of the device, one liter of water sample could be concentrated to 5 mL and the sensitivity of traditional purge and trap-gas chromatography-mass spectrometry (P&T-GC-MS) could be improved 1-2 orders of magnitude. Source and disinfected water samples from a water treatment plant were analyzed with this method. Compared with the traditional P&T-GC-MS analysis without pre-enrichment, the numbers of identified VOCs were improved from 0 to 16 for source water and 5 to 35 for disinfected water samples. It is also shown that there are many halide compounds in VOCs in disinfected water which do not exist in source water.

  14. Impact of geographic variations of the convective and dehydration center on stratospheric water vapor over the Asian monsoon region

    Directory of Open Access Journals (Sweden)

    K. Zhang

    2016-06-01

    Full Text Available The Asian monsoon region is the most prominent moisture center of water vapor in the lower stratosphere (LS during boreal summer. Previous studies have suggested that the transport of water vapor to the Asian monsoon LS is controlled by dehydration temperatures and convection mainly over the Bay of Bengal and Southeast Asia. However, there is a clear geographic variation of convection associated with the seasonal and intra-seasonal variations of the Asian monsoon circulation, and the relative influence of such a geographic variation of convection vs. the variation of local dehydration temperatures on water vapor transport is still not clear. Using satellite observations from the Aura Microwave Limb Sounder (MLS and a domain-filling forward trajectory model, we show that almost half of the seasonal water vapor increase in the Asian monsoon LS are attributable to geographic variations of convection and resultant variations of the dehydration center, of which the influence is comparable to the influence of the local dehydration temperature increase. In particular, dehydration temperatures are coldest over the southeast and warmest over the northwest Asian monsoon region. Although the convective center is located over Southeast Asia, an anomalous increase of convection over the northwest Asia monsoon region increases local diabatic heating in the tropopause layer and air masses entering the LS are dehydrated at relatively warmer temperatures. Due to warmer dehydration temperatures, anomalously moist air enters the LS and moves eastward along the northern flank of the monsoon anticyclonic flow, leading to wet anomalies in the LS over the Asian monsoon region. Likewise, when convection increases over the Southeast Asia monsoon region, dry anomalies appear in the LS. On a seasonal scale, this feature is associated with the monsoon circulation, convection and diabatic heating marching towards the northwest Asia monsoon region from June to August. The

  15. Evaluation of the sensitivity limits of water vapor transmission rate measurements using electrical calcium test

    Science.gov (United States)

    Kempe, Michael D.; Reese, Matthew O.; Dameron, Arrelaine A.

    2013-02-01

    The development of flexible organic light emitting diode displays and flexible thin film photovoltaic devices is dependent on the use of flexible, low-cost, optically transparent and durable barriers to moisture and/or oxygen. It is estimated that this will require high barriers with water vapor transmission rates (WVTR) between 10-4 and 10-6 g/m2/day. Thus, there is a need to develop a relatively fast, low cost, and quantitative method to evaluate such low permeation rates. Prior works have demonstrated that Ca films, because they change optically and electrically upon reaction with moisture, can be used as a sensor, enabling one to calculate a WVTR between 10 and 10-6 g/m2/day or better. In this work, we analyze the accuracy of an electrical Ca test method. We focus on the effects of the addition of a diffusion spacer and the effects of interactions of edge-seal material with changes to the spacer contacting surface on the overall accuracy. Furthermore, we examine a series of factors that can lead to different errors resulting in qualitative rather than quantitative Ca test behavior. We demonstrate that accurate, relatively high throughput, and reproducible measurements are possible for very low WVTR films in the 10-6 g/m2/day range.

  16. Structure and Variability of Water Vapor in the Upper Troposphere and Lower Stratosphere

    Science.gov (United States)

    Salby, Murry L.

    2003-01-01

    An algorithm has been developed to synoptically-map asynoptic measurements, while rejecting small-scale under-sampled variance that is intrinsic to satellite measurements of water vapor, cloud, and other convective properties. The algorithm has been validated against high-resolution Global Cloud Imagery (GCI) , constructed from 6 satellites simultaneously viewing the global convective pattern. It has been applied to synoptically map Upper-tropospheric humidity (UTH) from UARS/MLS. Mapped distributions of UTH have been used, jointly with the GCI, to study how the upper troposphere is humidified. The time-mean distribution of UTH is spatially correlated to the time-mean distribution of cold cloud fraction eta(sub c) (T less than 230 K). Regions of large UTH coincide with regions of large eta(sub c), which mark deep convection. They also coincide with regions of reduced vertical stability, in which the vertical gradient of Theta is weakened by convective mixing. Coldest cloud cover is attended convective overshoots above the local tropopause, which is simultaneously coldest and highest. Together, these features reflect the upper-troposphere being ventilated by convection, which mixes in air from lower levels.

  17. Detection of Dry Intrusion on Water Vapor Images Over Central Europe - June 2010 TO September 2011

    Science.gov (United States)

    Novotny, J.; Dejmal, K.; Hudec, F.; Kolar, P.

    2016-06-01

    The knowledge of evaluation of the intensity of cyclogenesis which could be connected with the weather having a significant impact on Earth's surface is quite useful. If, as one of the basic assumptions, the existence of connection between dry intrusions, dry bands, tropopause height and warm dark areas distribution on water vapor images (WV images) is considered, it is possible to set up a method of detecting dry intrusions on searching and tracking areas with higher brightness temperature compared with the surrounding environment. This paper covers the period between June 2010 and September 2011 over Central Europe. The ISIS method (Instrument de Suivi dans I'Imagerie satellitaire), originally developed for detection of cold cloud tops, was used as an initial ideological point. Subsequently, this method was modified by Michel and Bouttier for usage on WV images. Some of the applied criteria and parameters were chosen with reference to the results published by Michel and Bouttier as well as by Novotny. The procedure can be divided into two steps: detection of warm areas and their tracking. Cases of detection of areas not evidently connected with dry intrusions can be solved by filtering off based on the connection between detected warm areas to the cyclonic side of jet streams and significant lowering of the tropopause.

  18. Graphene nanoplatelets-reinforced polyetherimide foams prepared by water vapor-induced phase separation

    Directory of Open Access Journals (Sweden)

    H. Abbasi

    2015-05-01

    Full Text Available The present work considers the preparation of medium-density polyetherimide foams reinforced with variable amounts of graphene nanoplatelets (1–10 wt% by means of water vapor-induced phase separation (WVIPS and their characterization . A homogeneous closed-cell structure with cell sizes around 10 µm was obtained, with foams exhibiting zero crystallinity according to X-ray diffraction (XRD. Thermogravimetric analysis under nitrogen showed a two-step thermal decomposition behaviour for both unfilled and graphene-reinforced foams, with foams containing graphene presenting thermal stability improvements, related to a physical barrier effect promoted by the nanoplatelets. Thermo-mechanical analysis indicated that the specific storage modulus of the nanocomposite foams significantly increased owing to the high stiffness of graphene and finer cellular morphology of the foams. Although foamed nanocomposites displayed no further sign of graphene nanoplatelets exfoliation, the electrical conductivity of these foams was significant even for low graphene contents, with a tunnel-like model fitting well to the evolution of the electrical conductivity with the amount of graphene.

  19. Airborne Lidar for Simultaneous Measurement of Column CO2 and Water Vapor in the Atmosphere

    Science.gov (United States)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Antill, Charles W.; Remus, Ruben; Yu, Jirong

    2016-01-01

    The 2-micron wavelength region is suitable for atmospheric carbon dioxide (CO2) measurements due to the existence of distinct absorption feathers for the gas at this particular wavelength. For more than 20 years, researchers at NASA Langley Research Center (LaRC) have developed several high-energy and high repetition rate 2-micron pulsed lasers. This paper will provide status and details of an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar. The development of this active optical remote sensing IPDA instrument is targeted for measuring both CO2 and water vapor (H2O) in the atmosphere from an airborne platform. This presentation will focus on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver telescope, detection system and data acquisition. Future plans for the IPDA lidar system for ground integration, testing and flight validation will also be presented.

  20. Trends and Variability in Precipitable Water Vapor throughout North China from 1979 to 2015

    Directory of Open Access Journals (Sweden)

    Wang Peng

    2017-01-01

    Full Text Available This study analyzed the variability and trends in precipitable water vapor (PWV in North China from 1979 to 2015. The spatial distribution of annual mean PWV was generally characterized by two high PWV centers in Eastern China and the Tarim Basin and two low PWV centers in Northern Tibet and Qinghai Province and in Inner Mongolia. The levels of seasonal mean PWV were highest in summer, followed by autumn and spring, and lowest in winter. The maximum monthly mean PWV occurred in July and August, while the minimum occurred in December to February. Increasing trends in PWV, with the trend magnitude ranging from 0.1 to 1.2 mm decade−1 over North China, were observed in the radiosonde, ERA-interim, and MERRA-2 PWV data from 1979 to 1999; but a slightly decreasing trend of −0.4 mm decade−1 from radiosonde was found in most regions of North China from 1979 to 2007. A monotonically increasing PWV trend was detected throughout North China between 1979 and 1999, with the maximum trend occurring in summer and the minimum occurring in winter. For the period of 1979–2007, a slightly but less marked decreasing trend was found at most stations in North China in all four seasons.

  1. Turbulent mixed convection of heat and water vapor transfers in a two-dimensional vegetation canopy

    Energy Technology Data Exchange (ETDEWEB)

    Banna, M. [Laboratoire sur l' Energie Solaire, Universite de Lome, Faculte des Sciences, BP 1515, Lome (Togo); Pietri, L.; Zeghmati, B. [Centre d' Etudes Fondamentales, Groupe de Mecanique Acoustique et Instrumentation (CEF-GMAI), Universite de Perpignan, 52 avenue de Villeneuve, 66860 Perpignan (France)

    2004-08-01

    The present study consists in a numerical investigation of turbulent mixed-convection of heat and water vapor transfers inside two-dimensional (2-D) vegetation canopy, in the surrounding atmosphere and in a wet underground. The time-averaged Navier-Stokes equations are used to characterize the flow field surrounding the canopy and within it. Reynolds shear stresses are calculated using the eddy turbulence model and the Prandtl mixing length. The governing equations are solved numerically using an implicit finite difference method and Thomas algorithm. The present model is used for the determination of the micro climatic profiles such as streamlines, isotherms and iso-concentration. Special emphasis is laid on the systematic analysis of the total evaporation rate (evapotranspiration), the local and average heat fluxes, the Nusselt and Sherwood numbers. The effects of Leaf Area Density distribution, the canopy stomata regulation, as well as the atmospheric forcing conditions on the transfers, are presented and analysed. The results show that buoyancy force caused by properties variation reduces the local heat and mass transfer coefficients, and that this reduction increases at lower wind velocities. (orig.)

  2. Precipitable Water Vapor Estimates in the Australian Region from Ground-Based GPS Observations

    Directory of Open Access Journals (Sweden)

    Suelynn Choy

    2015-01-01

    Full Text Available We present a comparison of atmospheric precipitable water vapor (PWV derived from ground-based global positioning system (GPS receiver with traditional radiosonde measurement and very long baseline interferometry (VLBI technique for a five-year period (2008–2012 using Australian GPS stations. These stations were selectively chosen to provide a representative regional distribution of sites while ensuring conventional meteorological observations were available. Good agreement of PWV estimates was found between GPS and VLBI comparison with a mean difference of less than 1 mm and standard deviation of 3.5 mm and a mean difference and standard deviation of 0.1 mm and 4.0 mm, respectively, between GPS and radiosonde measurements. Systematic errors have also been discovered during the course of this study, which highlights the benefit of using GPS as a supplementary atmospheric PWV sensor and calibration system. The selected eight GPS sites sample different climates across Australia covering an area of approximately 30° NS/EW. It has also shown that the magnitude and variation of PWV estimates depend on the amount of moisture in the atmosphere, which is a function of season, topography, and other regional climate conditions.

  3. Aerosol absorption measurement at SWIR with water vapor interference using a differential photoacoustic spectrometer.

    Science.gov (United States)

    Zhu, Wenyue; Liu, Qiang; Wu, Yi

    2015-09-07

    Atmospheric aerosol plays an important role in atmospheric radiation balance through absorbing and scattering the solar radiation, which changes local weather and global climate. Accurate measurement is highly requested to estimate the radiative effects and climate effects of atmospheric aerosol. Photoacoustic spectroscopy (PAS) technique, which observes the aerosols on their natural suspended state and is insensitive to light scattering, is commonly recognized as one of the best candidates to measure the optical absorption coefficient (OAC) of aerosols. In the present work, a method of measuring aerosol OAC at the wavelength where could also be absorbed by water vapor was proposed and corresponding measurements of the absorption properties of the atmospheric aerosol at the short wave infrared (SWIR, 1342 nm) wavelength were carried out. The spectrometer was made up of two high performance homemade photoacoustic cells. To improve the sensitivity, several methods were presented to control the noise derived from gas flow and vibration from the sampling pump. Calibration of the OAC and properties of the system were also studied in detail. Using the established PAS instrument, measurement of the optical absorption properties of the atmospheric aerosol were carried out in laboratory and field environment.

  4. A Fiber-Optic Coupled Telescope for Water Vapor DIAL Receivers

    Science.gov (United States)

    DeYoung, Russell J.; Lonn, Frederick

    1998-01-01

    A fiber-optic coupled telescope of low complexity was constructed and tested. The major loss mechanisms of the optical system have been characterized. Light collected by the receiver mirror is focused onto an optical fiber, and the output of the fiber is filtered by an interference filter and then focused onto an APD detector. This system was used in lidar field measurements with a 532-nm Nd:YAG laser beam. The results were encouraging. A numerical model used for calculation of the expected return signal agreed with the lidar return signal obtained. The assembled system was easy to align and operate and weighed about 8 kg for a 30 cm (12") mirror system. This weight is low enough to allow mounting of the fiber-optic telescope receiver system in a UAV. Furthermore, the good agreement between the numerical lidar model and the performance of the actual receiver system, suggests that this model may be used for estimation of the performance of this and other lidar systems in the future. Such telescopes are relatively easy to construct and align. The fiber optic cable allows easy placement of the optical detector in any position. These telescope systems should find widespread use in aircraft and space home DIAL water vapor receiver systems.

  5. The High-Resolution Spectrum of Water Vapor between 11 600 and 12 750 cm-1

    Science.gov (United States)

    Flaud; Camy-Peyret; Bykov; Naumenko; Petrova; Scherbakov; Sinitsa

    1997-06-01

    The absorption spectrum of water vapor has been recorded between 11 600 and 12 750 cm-1 with a Fourier transform spectrometer (Kitt Peak, Az) at a resolution of 0.012 cm-1 and with a path length of 434 m. The line assignment has led to the determination of 506 accurate energy levels of the (310) (211), (112), (013), (230), (131), (032), and (051) vibrational states which belong to the so-called 3nu + delta resonance polyad. The rotational energy levels obtained are on the average in agreement with those reported recently by R. Toth (J. Mol. Spectrosc. 166, 176-183 (1994)) for the strong bands, but there are differences for high J levels or weak bands levels (about 15% of all levels). The experimental rotational energy levels have been fitted using Pade-Borel approximants and a set of 104 vibrational energies and rotational, resonance, and centrifugal distortion constants for the (310), (211), (112), (013), (230), (131), (032), and (051) vibrational states have been determined.

  6. Incorporation of bentonite clay in cassava starch films for the reduction of water vapor permeability.

    Science.gov (United States)

    Monteiro, M K S; Oliveira, V R L; Santos, F K G; Barros Neto, E L; Leite, R H L; Aroucha, E M M; Silva, R R; Silva, K N O

    2018-03-01

    Complete factorial planning 2 3 was applied to identify the influence of the cassava starch(A), glycerol(B) and modified clay(C) content on the water vapor permeability(WVP) of the cassava starch films with the addition of bentonite clay as a filler, its surface was modified by ion exchange from cetyltrimethyl ammonium bromide. The films were characterized by X-ray diffraction(XRD), fourier transform by infrared radiation(FTIR), atomic force microscopy(AFM) and scanning electron microscopy(SEM). The factorial analysis suggested a mathematical model thats predicting the optimal condition of the minimization of WVP. The influence of each individual factor and interaction in the WVP was investigated by Pareto graph, response surface and the optimization was established by the desirability function. The sequence of the degree of statistical significance of the investigated effects on the WVP observed in the Pareto graph was C>B>A>BC>AC. Interactions AB, BC and AC showed that the modified clay was the factor of greater significance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Roughness Length of Water Vapor over Land Surfaces and Its Influence on Latent Heat Flux

    Directory of Open Access Journals (Sweden)

    Sang-Jong Park

    2010-01-01

    Full Text Available Latent heat flux at the surface is largely dependent on the roughness length for water vapor (z0q. The determination of z0q is still uncertain because of its multifaceted characteristics of surface properties, atmospheric conditions and insufficient observations. In this study, observed values from the Fluxes Over Snow Surface II field experiment (FLOSS-II from November 2002 to March 2003 were utilized to estimate z0q over various land surfaces: bare soil, snow, and senescent grass. The present results indicate that the estimated z0q over bare soil is much smaller than the roughness length of momentum (z0m; thus, the ratio z0m/z0q is larger than those of previous studies by a factor of 20 - 150 for the available flow regime of the roughness Reynolds number, Re* > 0.1. On the snow surface, the ratio is comparable to a previous estimation for the rough flow (Re* > 1, but smaller by a factor of 10 - 50 as the flow became smooth (Re* < 1. Using the estimated ratio, an optimal regression equation of z0m/z0q is determined as a function of Re* for each surface type. The present parameterization of the ratio is found to greatly reduce biases of latent heat flux estimation compared with that estimated by the conventional method, suggesting the usefulness of current parameterization for numerical modeling.

  8. Airborne lidar for simultaneous measurement of column CO2 and water vapor in the atmosphere

    Science.gov (United States)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Antill, Charles W.; Remus, Ruben; Yu, Jirong

    2016-10-01

    The 2-micron wavelength region is suitable for atmospheric carbon dioxide (CO2) measurements due to the existence of distinct absorption feathers for the gas at this particular wavelength. For more than 20 years, researchers at NASA Langley Research Center (LaRC) have developed several high-energy and high repetition rate 2-micron pulsed lasers. This paper will provide status and details of an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar. The development of this active optical remote sensing IPDA instrument is targeted for measuring both CO2 and water vapor (H2O) in the atmosphere from an airborne platform. This presentation will focus on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver telescope, detection system and data acquisition. Future plans for the IPDA lidar system for ground integration, testing and flight validation will also be presented.

  9. Ultra Narrowband Optical Filters for Water Vapor Differential Absorption Lidar (DIAL) Atmospheric Measurements

    Science.gov (United States)

    Stenholm, Ingrid; DeYoung, Russell J.

    2001-01-01

    Differential absorption lidar (DIAL) systems are being deployed to make vertical profile measurements of atmospheric water vapor from ground and airborne platforms. One goal of this work is to improve the technology of such DIAL systems that they could be deployed on space-based platforms. Since background radiation reduces system performance, it is important to reduce it. One way to reduce it is to narrow the bandwidth of the optical receiver system. However, since the DIAL technique uses two or more wavelengths, in this case separated by 0.1 nm, a fixed-wavelength narrowband filter that would encompass both wavelengths would be broader than required for each line, approximately 0.02 nm. The approach employed in this project is to use a pair of tunable narrowband reflective fiber Bragg gratings. The Bragg gratings are germanium-doped silica core fiber that is exposed to ultraviolet radiation to produce index-of-refraction changes along the length of the fiber. The gratings can be tuned by stretching. The backscattered laser radiation is transmitted through an optical circulator to the gratings, reflected back to the optical circulator by one of the gratings, and then sent to a photodiode. The filter reflectivities were >90 percent, and the overall system efficiency was 30 percent.

  10. An all-fiber spectroscopic Raman lidar system for atmospheric water vapor measurements

    Science.gov (United States)

    Wang, Yufeng; Zhao, Meina; Fu, Qiang; Li, Zhao; Di, Huige; Wang, Li; Hua, Dengxin

    2016-01-01

    Aimed to establish a Raman lidar system with high-reliability and high anti-interference performance, an newly all-fiber spectroscopic Raman lidar system was proposed for atmospheric water vapor measurement, in which optical fiber couplers, fiber band-width filters and fiber F-P filters constitute the all-fiber spectroscopic system. On the basis of the design of fiber F-P filters and its transmission analysis, the series connection of optical fiber coupler is designed as fiber optics splitter, which is not only to obtain fiber coupling of the input and output of lidar returns, and also to achieve the optimal energy output ratio at three fiber channels. Furthermore, fiber band-width filters are proposed to replace the dichroic mirrors, and the structure of fiber band-width filters and fiber F-P filters is to constitute the secondary cascade filter system, achieving the fine extraction of interested spectrum and high rejection rate to elastic scattering signals. Preliminary test results indicated that, the energy at the three output ports is %sim;5: 2.5: 2.5, and the two fiber band-width filters are provided with the central wavelength of 606nm and 660nm, the bandwidth of 20nm, and the out of band inhibition of >0.5%, which met the design requirements. The design and results will provide a reliable basis for the integration and experiment of the subsequent all-fiber spectroscopic system.

  11. Water vapor in the spectrum of the extrasolar planet HD 189733b. II. The eclipse

    Energy Technology Data Exchange (ETDEWEB)

    Crouzet, Nicolas [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); McCullough, Peter R. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Madhusudhan, Nikku, E-mail: crouzet@dunlap.utoronto.ca [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2014-11-10

    Spectroscopic observations of exoplanets are crucial to infer the composition and properties of their atmospheres. HD 189733b is one of the most extensively studied exoplanets and is a cornerstone for hot Jupiter models. In this paper, we report the dayside emission spectrum of HD 189733b in the wavelength range 1.1-1.7 μm obtained with the Hubble Space Telescope Wide Field Camera 3 (WFC3) in spatial scan mode. The quality of the data is such that even a straightforward analysis yields a high-precision Poisson noise-limited spectrum: the median 1σ uncertainty is 57 ppm per 0.02 μm bin. We also build a white-light curve correcting for systematic effects and derive an absolute eclipse depth of 96 ± 39 ppm. The resulting spectrum shows marginal evidence for water vapor absorption, but can also be well explained by a blackbody spectrum. However, the combination of these WFC3 data with previous Spitzer photometric observations is best explained by a dayside atmosphere of HD 189733b with no thermal inversion and a nearly solar or subsolar H{sub 2}O abundance in a cloud-free atmosphere. Alternatively, this apparent subsolar abundance may be the result of clouds or hazes that future studies need to investigate.

  12. Correction Technique for Raman Water Vapor Lidar Signal-Dependent Bias and Suitability for Water Wapor Trend Monitoring in the Upper Troposphere

    Science.gov (United States)

    Whiteman, D. N.; Cadirola, M.; Venable, D.; Calhoun, M.; Miloshevich, L; Vermeesch, K.; Twigg, L.; Dirisu, A.; Hurst, D.; Hall, E.; hide

    2012-01-01

    The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE (Atmospheric Laboratory for Validation, Interagency Collaboration and Education) mobile laboratory in the MOHAVE-2009 campaign. In appendices we also report on the performance of the corrected Vaisala RS92 radiosonde measurements during the campaign, on a new radiosonde based calibration algorithm that reduces the influence of atmospheric variability on the derived calibration constant, and on other results of the ALVICE deployment. The MOHAVE-2009 campaign permitted the Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated, revealing that wet biases in upper tropospheric (UT) and lower stratospheric (LS) water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the bias. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Good agreement is found between corrected ALVICE lidar measurments and those of RS92, frost point hygrometer and total column water. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most robust. The correction shown here holds promise for permitting useful upper

  13. Diurnal variation of atmospheric water vapor at Gale crater: Analysis from ground-based measurements

    Science.gov (United States)

    Martinez, German; McConnochie, Timothy; Renno, Nilton; Meslin, Pierre-Yves; Fischer, Erik; Vicente-Retortillo, Alvaro; Borlina, Caue; Kemppinen, Osku; Genzer, Maria; Harri, Ari-Matti; de la Torre-Juárez, Manuel; Zorzano, Mari-Paz; Martin-Torres, Javier; Bridges, Nathan; Maurice, Sylvestre; Gasnault, Olivier; Gomez-Elvira, Javier; Wiens, Roger

    2016-04-01

    We analyze measurements obtained by Curiosity's Rover Environmental Monitoring Station (REMS) and ChemCam (CCAM) instruments to shed light on the hydrological cycle at Gale crater. In particular, we use nighttime REMS measurements taken when the atmospheric volume mixing ratio (VMR) and its uncertainty are the lowest (between 05:00 and 06:00 LTST) [1], and daytime CCAM passive sky measurements taken when the VMR is expected to be the highest (between 10:00 and 14:00 LTST) [2]. VMR is calculated from simultaneous REMS measurements of pressure (P), temperature (T) and relative humidity (RH) at 1.6 m (VMR is defined as RH×es(T)/P , where es is the saturation water vapor pressure over ice). The REMS relative humidity sensor has recently been recalibrated (June 2015), providing RH values slightly lower than those in the previous calibration (Dec 2014). The full diurnal cycle of VMR cannot be analyzed using only REMS data because the uncertainty in daytime VMR derived from REMS measurements is extremely high. Daytime VMR is inferred by fitting the output of a multiple-scattering discrete-ordinates radiative transfer model to CCAM passive sky observations [3]. CCAM makes these observations predominately in the vicinity of 11:00 - 12:00 LTST, but occasionally in the early morning near 08:00 LTST. We find that throughout the Martian year, the daytime VMR is higher than at night, with a maximum day-to-night ratio of about 6 during winter. Various processes might explain the differences between nighttime REMS and daytime CCAM VMR values. Potential explanations include: (i) surface nighttime frost formation followed by daytime sublimation [1], (ii) surface nighttime adsorption of water vapor by the regolith followed by daytime desorption and (iii) large scale circulations changing vertical H2O profiles at different times of the year. Potential formation of surface frost can only occur in late fall and winter [1], coinciding with the time when the diurnal amplitude of the near

  14. An energy balance model exploration of the impacts of interactions between surface albedo, cloud cover and water vapor on polar amplification

    Science.gov (United States)

    Södergren, A. Helena; McDonald, Adrian J.; Bodeker, Gregory E.

    2017-11-01

    We examine the effects of non-linear interactions between surface albedo, water vapor and cloud cover (referred to as climate variables) on amplified warming of the polar regions, using a new energy balance model. Our simulations show that the sum of the contributions to surface temperature changes due to any variable considered in isolation is smaller than the temperature changes from coupled feedback simulations. This non-linearity is strongest when all three climate variables are allowed to interact. Surface albedo appears to be the strongest driver of this non-linear behavior, followed by water vapor and clouds. This is because increases in longwave radiation absorbed by the surface, related to increases in water vapor and clouds, and increases in surface absorbed shortwave radiation caused by a decrease in surface albedo, amplify each other. Furthermore, our results corroborate previous findings that while increases in cloud cover and water vapor, along with the greenhouse effect itself, warm the polar regions, water vapor also significantly warms equatorial regions, which reduces polar amplification. Changes in surface albedo drive large changes in absorption of incoming shortwave radiation, thereby enhancing surface warming. Unlike high latitudes, surface albedo change at low latitudes are more constrained. Interactions between surface albedo, water vapor and clouds drive larger increases in temperatures in the polar regions compared to low latitudes. This is in spite of the fact that, due to a forcing, cloud cover increases at high latitudes and decreases in low latitudes, and that water vapor significantly enhances warming at low latitudes.

  15. F.E.A.S.T.

    Science.gov (United States)

    ... Registration F.A.Q. About F.E.A.S.T. History Organizational Information Board of Directors Professional Advisory Panel ... evidence-based treatment, and advocating for research and education to reduce the suffering associated ... believes that empowered caregivers are essential to the ...

  16. Effect of Water Vapor During Secondary Cooling on Hot Shortness in Fe-Cu-Ni-Sn-Si Alloys

    Science.gov (United States)

    Sampson, Erica; Sridhar, Seetharaman

    2014-10-01

    Residual Cu in recycled steel scrap can cause hot shortness when the iron matrix is oxidized. Hot shortness can occur directly after the solid steel is formed from continuous casting as the steel undergoes a cooling process known as secondary cooling where water is first sprayed on the surface to promote cooling. This is followed by a radiant cooling stage where the steel is cooled in air to room temperature. This investigation examines the roles of water vapor, Si content, temperature, and the presence of Sn in a Fe-0.2 wt pct Cu-0.05 wt pct Ni alloy on oxidation, separated Cu and Cu induced-hot shortness during simulations of the secondary cooling process. The secondary cooling from 1473 K (1200 °C) resulted in a slight increase in liquid quantity and grain boundary penetration as compared to the isothermal heating cycles at 1423 K (1150 °C) due to the higher temperatures experienced in the non-isothermal cycle. The addition of water vapor increased the sample oxidation as compared to samples processed in dry atmospheres due to increased scale adherence, scale plasticity, and inward transport of oxygen. The increase in weight gain of the wet atmosphere increased the liquid formation at the interface in the non-Si containing alloys. The secondary cooling cycle with water vapor and the effect of Sn lead to the formation of many small pools of Cu-rich liquid embedded within the surface of the metal due to the Sn allowing for increased grain boundary decohesion and the water vapor allowing for oxidation within liquid-penetrated grain boundaries. The presence of Si increased the amount of occlusion of Cu and Fe, significantly decreasing the quantity of liquid at the interface and the amount of grain boundary penetration.

  17. Water Vapor Feedback and Links to Mechanisms of Recent Tropical Climate Variations

    Science.gov (United States)

    Robertson, F. R.; Miller, Tim L.

    2008-01-01

    Recent variations of tropical climate on interannual to near-decadal scales have provided a useful target for studying feedback processes. A strong warm/cold ENSO couplet (e.g. 1997-2000) along with several subsequent weaker events are prominent interannual signals that are part of an apparent longer term strengthening of the Walker circulation during the mid to late1990 s with some weakening thereafter. Decadal scale changes in tropical SST structure during the 1990s are accompanied by focusing of precipitation over the Indo-Pacific warm pool and an increase in tropical ocean evaporation of order 1.0 %/decade. Here we use a number of diverse satellite measurements to explore connections between upper-tropospheric humidity (UTH) variations on these time scales and changes in other water and energy fluxes. Precipitation (GPCP, TRMM), turbulent fluxes (OAFlux), and radiative fluxes (ERBE / CERES, SRB) are use to analyze vertically-integrated divergence of moist static energy, divMSE, and its dry and moist components. Strong signatures of MSE flux transport linking ascending and descending regions of tropical circulations are found. Relative strengths of these transports compared to radiative flux changes are interpreted as a measure of efficiency in the overall process of heat rejection during episodes of warm or cold SST forcing. In conjunction with the diagnosed energy transports we explore frequency distributions of upper-tropospheric humidity as inferred from SSM/T-2 and AMSU-B passive microwave measurements. Relating these variations to SST changes suggests positive water vapor feedback, but at a level reduced from constant relative humidity.

  18. Spatially Resolved Temperature and Water Vapor Concentration Distributions in Supersonic Combustion Facilities by TDLAT

    Science.gov (United States)

    Busa, K. M.; McDaniel J. C.; Diskin, G. S.; DePiro, M. J.; Capriotti, D. P.; Gaffney, R. L.

    2012-01-01

    Detailed knowledge of the internal structure of high-enthalpy flows can provide valuable insight to the performance of scramjet combustors. Tunable Diode Laser Absorption Spectroscopy (TDLAS) is often employed to measure temperature and species concentration. However, TDLAS is a path-integrated line-of-sight (LOS) measurement, and thus does not produce spatially resolved distributions. Tunable Diode Laser Absorption Tomography (TDLAT) is a non-intrusive measurement technique for determining two-dimensional spatially resolved distributions of temperature and species concentration in high enthalpy flows. TDLAT combines TDLAS with tomographic image reconstruction. More than 2500 separate line-of-sight TDLAS measurements are analyzed in order to produce highly resolved temperature and species concentration distributions. Measurements have been collected at the University of Virginia's Supersonic Combustion Facility (UVaSCF) as well as at the NASA Langley Direct-Connect Supersonic Combustion Test Facility (DCSCTF). Due to the UVaSCF s unique electrical heating and ability for vitiate addition, measurements collected at the UVaSCF are presented as a calibration of the technique. Measurements collected at the DCSCTF required significant modifications to system hardware and software designs due to its larger measurement area and shorter test duration. Tomographic temperature and water vapor concentration distributions are presented from experimentation on the UVaSCF operating at a high temperature non-reacting case for water vitiation level of 12%. Initial LOS measurements from the NASA Langley DCSCTF operating at an equivalence ratio of 0.5 are also presented. Results show the capability of TDLAT to adapt to several experimental setups and test parameters.

  19. Computing Carbon Dioxide and Water Vapor Fluxes Everywhere, All of the Time

    Science.gov (United States)

    Baldocchi, D. D.; Ryu, Y.; Kobayashi, H.

    2011-12-01

    We examine a hierarchy of biophysical models which aim to produce information on the 'breathing of the biosphere' that is 'everywhere, all of the time'. The computational demands of this problem are daunting because the science must transcend fourteen orders of magnitude in time and space as one evaluates a panoply of non-linear biophysical processes from the dimension of the chloroplast of leaves to the globe. At the canopy to landscape scales, one must simulate the micro-habitat conditions of thousands of leaves, as they are displayed on groups of plants with a variety of angle orientations. Then one must apply the micro-habitat information (e.g. sunlight, temperature, humidity, CO2 concentration) to sets of coupled non-linear equations that simulate photosynthesis, respiration and the energy balance of the leaves to add up this information. In sparse canopies three-dimensional radiative transfer models are needed. At the regional to global scales, it is pertinent to apply lessons learned at the canopy scale and drive a system of biophysical equations, called the Breathing-Earth Science Simulator (BESS), with multiple layers of remote sensing datasets at high resolution (1 km) and frequent intervals (daily) to predict carbon dioxide and water vapor exchange. And parameterize these models with emerging ecological rules that can be assessed with remote sensing. With BESS, the global data products of ecosystem photosynthesis and transpiration compare well with direct flux measurements, and produce complex spatial and temporal patterns that will prove to be valuable for environmental modelers and scientists studying climate change and carbon and water cycles from local to global scales.

  20. UNIQUAC activity coefficient model and modified Redlich- Kwong EOS for the vapor liquid equilibrium systems of carbon dioxide-water

    Directory of Open Access Journals (Sweden)

    Nurak Grisdanurak

    2004-11-01

    Full Text Available The UNIQUAC activity coefficient model and fugacity coefficient model of modified Redlich-Kwong predicted vapor-liquid equilibrium between carbon dioxide and water efficiently. The activity coefficient model needed the energy interaction parameters between molecules of carbon dioxide and water. Those parameters can be obtained by non-linear regression method of the experimental data of the vapor-liquid equilibria of carbon dioxide and water (Lide, 1992. The fugacity coefficient model of modified Redlich- Kwong needed only some physical properties of carbon dioxide and water without any interaction parameters. The experimental data had ranges of temperature and partial pressure of carbon dioxide between 10 to 100ºC and 5 to 1,200 kPa, respectively. The parameters for the activity coefficient model are temperature dependent but are not concentration dependent. The regression results gave good agreements with the experimental data in which the mean absolute error (MAE between experiment and calculated partial pressure of carbon dioxide was 2.72% and the mean absolute standard deviation (MAD of that error was 1.35%. Comparing the effects of activity coefficients and fugacity coefficients, we found that the non-ideality in vapor phase was more influential than the non-ideality in liquid phase.

  1. Numerical Analyses and Forecasting of Surface Air Temperature and Water Vapor Pressure.

    Science.gov (United States)

    Analyses and forecasting of heat exchange, fog probability and visibility over the oceans and a number of other numerical environmental analyses/forecasts require a detailed analysis and forecasting of surface air vapor pressure and temperature. Based on earlier encouraging studies by a few Norwegian researchers, such response computation and numerical analysis/forecasting of surface air vapor pressure and temperature is outlined. It is shown that the changes of surface air properties, and sea- air temperature and vapor pressure differences are mainly determined by

  2. Estimation of the Total Atmospheric Water Vapor Content and Land Surface Temperature Based on AATSR Thermal Data

    Science.gov (United States)

    Zhang, Tangtang; Wen, Jun; van der Velde, Rogier; Meng, Xianhong; Li, Zhenchao; Liu, Yuanyong; Liu, Rong

    2008-01-01

    The total atmospheric water vapor content (TAWV) and land surface temperature (LST) play important roles in meteorology, hydrology, ecology and some other disciplines. In this paper, the ENVISAT/AATSR (The Advanced Along-Track Scanning Radiometer) thermal data are used to estimate the TAWV and LST over the Loess Plateau in China by using a practical split window algorithm. The distribution of the TAWV is accord with that of the MODIS TAWV products, which indicates that the estimation of the total atmospheric water vapor content is reliable. Validations of the LST by comparing with the ground measurements indicate that the maximum absolute derivation, the maximum 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 a new way to estimate the LST from AATSR data. PMID:27879795

  3. Impact of freeze-drying, mixing and horizontal transport on water vapor in the upper troposphere and lower stratosphere (UTLS)

    Science.gov (United States)

    Poshyvailo, Liubov; Ploeger, Felix; Müller, Rolf; Tao, Mengchu; Konopka, Paul; Abdoulaye Diallo, Mohamadou; Grooß, Jens-Uwe; Günther, Gebhard; Riese, Martin

    2017-04-01

    Water vapor in the upper troposphere and lower stratosphere (UTLS) is a key player in the global radiation budget. Therefore, a realistic representation of the water vapor distribution in this region and the involved control processes is critical for climate models, but largely uncertain hitherto. It is known that the extremely low temperatures around the tropical tropopause cause the dominant factor controlling water vapor in the lower stratosphere. Here, we focus on additional processes, such as horizontal transport between tropics and extratropics, small-scale mixing, and freeze-drying. We assess the sensitivities of simulated water vapor in the UTLS from simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS). CLaMS is a Lagrangian transport model, with a parameterization of small-scale mixing (model diffusion) which is coupled to deformations in the large-scale flow. First, to assess the robustness of water vapor with respect to the meteorological datasets we examine CLaMS driven by ECMWF ERA-Interim and the Japanese 55-year reanalysis. Second, to investigate the effects of small-scale mixing we vary the parameterized mixing strength in the CLaMS model between the reference case with the mixing strength optimized to reproduce atmospheric trace gas observations and a purely advective simulation with parameterized mixing turned off. Also calculation of Lagrangian cold points gives further insight of the processes involved. Third, to assess the effects of horizontal transport between the tropics and extratropics we carry out sensitivity simulations with horizontal transport barriers along latitude circles at the equator, 15°N/S and 35°N/S. Finally, the impact of Antarctic dehydration is estimated from additional sensitivity simulations with switched off freeze-drying in the model at high latitudes of 50°N/S. Our results show that the uncertainty in the tropical tropopause temperatures between current reanalysis datasets causes significant

  4. Water Vapor Adsorption on Biomass Based Carbons under Post-Combustion CO2 Capture Conditions: Effect of Post-Treatment

    Directory of Open Access Journals (Sweden)

    Nausika Querejeta

    2016-05-01

    Full Text Available The effect of post-treatment upon the H2O adsorption performance of biomass-based carbons was studied under post-combustion CO2 capture conditions. Oxygen surface functionalities were partially replaced through heat treatment, acid washing, and wet impregnation with amines. The surface chemistry of the final carbon is strongly affected by the type of post-treatment: acid treatment introduces a greater amount of oxygen whereas it is substantially reduced after thermal treatment. The porous texture of the carbons is also influenced by post-treatment: the wider pore volume is somewhat reduced, while narrow microporosity remains unaltered only after acid treatment. Despite heat treatment leading to a reduction in the number of oxygen surface groups, water vapor adsorption was enhanced in the higher pressure range. On the other hand acid treatment and wet impregnation with amines reduce the total water vapor uptake thus being more suitable for post-combustion CO2 capture applications.

  5. Water Vapor Adsorption on Biomass Based Carbons under Post-Combustion CO2 Capture Conditions: Effect of Post-Treatment

    Science.gov (United States)

    Querejeta, Nausika; Plaza, Marta G.; Rubiera, Fernando; Pevida, Covadonga

    2016-01-01

    The effect of post-treatment upon the H2O adsorption performance of biomass-based carbons was studied under post-combustion CO2 capture conditions. Oxygen surface functionalities were partially replaced through heat treatment, acid washing, and wet impregnation with amines. The surface chemistry of the final carbon is strongly affected by the type of post-treatment: acid treatment introduces a greater amount of oxygen whereas it is substantially reduced after thermal treatment. The porous texture of the carbons is also influenced by post-treatment: the wider pore volume is somewhat reduced, while narrow microporosity remains unaltered only after acid treatment. Despite heat treatment leading to a reduction in the number of oxygen surface groups, water vapor adsorption was enhanced in the higher pressure range. On the other hand acid treatment and wet impregnation with amines reduce the total water vapor uptake thus being more suitable for post-combustion CO2 capture applications. PMID:28773488

  6. Observation of a strong inverse temperature dependence for the opacity of atmospheric water vapor in the mm continuum near 280 GHz

    Science.gov (United States)

    Emmons, Louisa K.; De Zafra, Robert L.

    1990-01-01

    Results are presented of the field measurements of atmospheric opacity at 278 GHz (9.3/cm) conducted at the McMurdo Station (Antarctica) during the austral springs of 1986 and 1987, in conjunction with balloon measurements of water vapor profile and total column density, showing a strong inverse temperature dependence when normalized to precipitable water vapor. The value of measured opacity per mm of precipitable water vapor (PWV) is roughly two times greater at -35 C than at -10 C and three times greater than measurements at +25 C reported by Zammit and Ade (1981). Various theories proposed to explain excess absorption in continuum regions are reviewed.

  7. Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements

    Science.gov (United States)

    Sahoo, Swaroop

    Observation of profiles of temperature, humidity and winds with sufficient accuracy and fine vertical and temporal resolution are needed to improve mesoscale weather prediction, track conditions in the lower to mid-troposphere, predict winds for renewable energy, inform the public of severe weather and improve transportation safety. In comparing these thermodynamic variables, the absolute atmospheric temperature varies only by 15%; in contrast, total water vapor may change by up to 50% over several hours. In addition, numerical weather prediction (NWP) models are initialized using water vapor profile information, so improvements in their accuracy and resolution tend to improve the accuracy of NWP. Current water vapor profile observation systems are expensive and have insufficient spatial coverage to observe humidity in the lower to mid-troposphere. To address this important scientific need, the principal objective of this dissertation is to improve the accuracy, vertical resolution and revisit time of tropospheric water vapor profiles retrieved from microwave and millimeter-wave brightness temperature measurements. This dissertation advances the state of knowledge of retrieval of atmospheric water vapor from microwave brightness temperature measurements. It focuses on optimizing two information sources of interest for water vapor profile retrieval, i.e. independent measurements and background data set size. From a theoretical perspective, it determines sets of frequencies in the ranges of 20-23, 85-90 and 165-200 GHz that are optimal for water vapor retrieval from each of ground-based and airborne radiometers. The maximum number of degrees of freedom for the selected frequencies for ground-based radiometers is 5-6, while the optimum vertical resolution is 0.5 to 1.5 km. On the other hand, the maximum number of degrees of freedom for airborne radiometers is 8-9, while the optimum vertical resolution is 0.2 to 0.5 km. From an experimental perspective, brightness

  8. Airborne DOAS retrievals of methane, carbon dioxide, and water vapor concentrations at high spatial resolution: application to AVIRIS-NG

    Science.gov (United States)

    Thorpe, Andrew K.; Frankenberg, Christian; Thompson, David R.; Duren, Riley M.; Aubrey, Andrew D.; Bue, Brian D.; Green, Robert O.; Gerilowski, Konstantin; Krings, Thomas; Borchardt, Jakob; Kort, Eric A.; Sweeney, Colm; Conley, Stephen; Roberts, Dar A.; Dennison, Philip E.

    2017-10-01

    At local scales, emissions of methane and carbon dioxide are highly uncertain. Localized sources of both trace gases can create strong local gradients in its columnar abundance, which can be discerned using absorption spectroscopy at high spatial resolution. In a previous study, more than 250 methane plumes were observed in the San Juan Basin near Four Corners during April 2015 using the next-generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) and a linearized matched filter. For the first time, we apply the iterative maximum a posteriori differential optical absorption spectroscopy (IMAP-DOAS) method to AVIRIS-NG data and generate gas concentration maps for methane, carbon dioxide, and water vapor plumes. This demonstrates a comprehensive greenhouse gas monitoring capability that targets methane and carbon dioxide, the two dominant anthropogenic climate-forcing agents. Water vapor results indicate the ability of these retrievals to distinguish between methane and water vapor despite spectral interference in the shortwave infrared. We focus on selected cases from anthropogenic and natural sources, including emissions from mine ventilation shafts, a gas processing plant, tank, pipeline leak, and natural seep. In addition, carbon dioxide emissions were mapped from the flue-gas stacks of two coal-fired power plants and a water vapor plume was observed from the combined sources of cooling towers and cooling ponds. Observed plumes were consistent with known and suspected emission sources verified by the true color AVIRIS-NG scenes and higher-resolution Google Earth imagery. Real-time detection and geolocation of methane plumes by AVIRIS-NG provided unambiguous identification of individual emission source locations and communication to a ground team for rapid follow-up. This permitted verification of a number of methane emission sources using a thermal camera, including a tank and buried natural gas pipeline.

  9. Reduced water vapor transmission rates of low-temperature solution-processed metal oxide barrier films via ultraviolet annealing

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seonuk; Jeong, Yong Jin; Baek, Yonghwa; Kim, Lae Ho; Jang, Jin Hyuk; Kim, Yebyeol [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); An, Tae Kyu [Department of Polymer Science & Engineering, Korea National University of Transportation, 50 Daehak-Ro, Chungju (Korea, Republic of); Nam, Sooji, E-mail: sjnam15@etri.re.kr [Information Control Device Section, Electronics and Telecommunications Research Institute, Daejeon, 305-700 (Korea, Republic of); Kim, Se Hyun, E-mail: shkim97@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, North Gyeongsang 712-749 (Korea, Republic of); Jang, Jaeyoung, E-mail: jyjang15@hanyang.ac.kr [Department of Energy Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Chan Eon, E-mail: cep@postech.ac.kr [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

    2017-08-31

    Highlights: • Sol-gel-derived aluminum oxide thin films were prepared using ultraviolet (UV) annealing. • UV irradiation dramatically promoted the densification of AlO{sub x} during the annealing stage, thereby forming a close-packed AlO{sub x} film. • The resulting AlO{sub x} films deposited on polymer substrates exhibited good water vapor blocking properties with low water vapor transmission rates (WVTRs). - Abstract: Here, we report the fabrication of low-temperature sol-gel-derived aluminum oxide (AlO{sub x}) films via ultraviolet (UV) annealing and the investigation of their water vapor blocking properties by measuring the water vapor transmission rates (WVTRs). The UV annealing process induced the formation of a dense metal-oxygen-metal bond (Al-O-Al structure) at low temperatures (<200 °C) that are compatible with commercial plastic substrates. The density of the UV-annealed AlO{sub x} thin film at 180 °C was comparable to that of AlO{sub x} thin films that have been thermally annealed at 350 °C. Furthermore, the UV-annealed AlO{sub x} thin films exhibited a high optical transparency in the visible region (>99%) and good electrical insulating properties (∼10{sup −7} A/cm{sup 2} at 2 MV/cm). Finally, we confirmed that a dense AlO{sub x} thin film was successfully deposited onto the plastic substrate via UV annealing at low temperatures, leading to a substantial reduction in the WVTRs. The Ca corrosion test was used to measure the WVTRs of AlO{sub x} thin films deposited onto polyethylene naphthalate or polyimide substrates, determined to be 0.0095 g m{sup −2} day{sup −1} (25 °C, 50% relative humidity) and 0.26 g m{sup −2} day{sup −1}, respectively.

  10. Airborne DOAS retrievals of methane, carbon dioxide, and water vapor concentrations at high spatial resolution: application to AVIRIS-NG

    Directory of Open Access Journals (Sweden)

    A. K. Thorpe

    2017-10-01

    Full Text Available At local scales, emissions of methane and carbon dioxide are highly uncertain. Localized sources of both trace gases can create strong local gradients in its columnar abundance, which can be discerned using absorption spectroscopy at high spatial resolution. In a previous study, more than 250 methane plumes were observed in the San Juan Basin near Four Corners during April 2015 using the next-generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG and a linearized matched filter. For the first time, we apply the iterative maximum a posteriori differential optical absorption spectroscopy (IMAP-DOAS method to AVIRIS-NG data and generate gas concentration maps for methane, carbon dioxide, and water vapor plumes. This demonstrates a comprehensive greenhouse gas monitoring capability that targets methane and carbon dioxide, the two dominant anthropogenic climate-forcing agents. Water vapor results indicate the ability of these retrievals to distinguish between methane and water vapor despite spectral interference in the shortwave infrared. We focus on selected cases from anthropogenic and natural sources, including emissions from mine ventilation shafts, a gas processing plant, tank, pipeline leak, and natural seep. In addition, carbon dioxide emissions were mapped from the flue-gas stacks of two coal-fired power plants and a water vapor plume was observed from the combined sources of cooling towers and cooling ponds. Observed plumes were consistent with known and suspected emission sources verified by the true color AVIRIS-NG scenes and higher-resolution Google Earth imagery. Real-time detection and geolocation of methane plumes by AVIRIS-NG provided unambiguous identification of individual emission source locations and communication to a ground team for rapid follow-up. This permitted verification of a number of methane emission sources using a thermal camera, including a tank and buried natural gas pipeline.

  11. Low-energy proton stopping power of N2, O2 and water vapor and deviations from Bragg's rule

    Science.gov (United States)

    Xu, Y. J.; Khandelwal, G. S.; Wilson, J. W.

    1984-01-01

    A modified local plasma model, based on the works of Lindhard and Winther; and Bethe, Brown, and Walske, is established. The Gordon-Kim model for molecular electron density is used to calculate stopping power of N2, O2, and water vapor for protons of energy ranging from 40 keV to 2.5 MeV, resulting in good agreement with experimental data. Deviations from Bragg's rule are evaluated and are discussed under the present theoretical model.

  12. Remote sensing of seasonal distribution of precipitable water vapor over the oceans and the inference of boundary-layer structure

    Science.gov (United States)

    Prabhakara, C.; Lo, R. C.; Nath, N. R.; Dalu, G.

    1979-01-01

    From the depth of the water vapor spectral lines in the 8-9 micron window region, measured by the Nimbus 4 Infrared Interferometer Spectrometer (IRIS) with a resolution of about 3/cm, the precipitable water vapor over the oceans is remotely sensed. In addition the IRIS spectral data in the 11-13 micron window region have been used to derive the sea surface temperature (SST). Seasonal maps of w on the oceans deduced from the spectral data reveal the dynamical influence of the large-scale atmospheric circulation. With the help of a model for the vertical distribution of water vapor, the configuration of the atmospheric boundary layer over the oceans can be inferred from these remotely sensed w and SST. The gross seasonal mean structure of the boundary layer inferred in this fashion reveals the broad areas of trade wind inversion and the convectively active areas such as the ITCZ. The derived information is in reasonable agreement with some observed climatological patterns over the oceans.

  13. Validation of Atmospheric Water Vapor Derived from Ship-Borne GPS Measurements in the Chinese Bohai Sea

    Directory of Open Access Journals (Sweden)

    Shi-Jie Fan

    2016-04-01

    Full Text Available Atmospheric water vapor (AWV was investigated for the first time in the Chinese Bohai Sea using a Global Positioning System (GPS receiver aboard a lightweight (300-ton ship. An experiment was conducted to retrieve the AWV using the state-of-the-art GPS precise point positioning (PPP technique. The effects of atmospheric weighted mean temperature model and zenith wet delay constraint on GPS AWV estimates were discussed in the PPP estimation system. The GPS-derived precipitable water vapor (PWV and slant-path water vapor (SWV were assessed by comparing with those derived from the Fifth Generation NCAR/Penn State Mesoscale Model (MM5. The results showed the PWV and SWV differences between those derived from both GPS and MM5 are 1.5 mm root mean square (RMS with a bias of 0.2 and 3.9 mm RMS with a bias of -0.7 mm respectively. These good agreements indicate that the GPS-derived AWV in dynamic environments has a comparable accuracy with that of the MM5 model. This suggests that high accuracy and high spatio-temporal resolution humidity fields can be obtained using GPS in the Chinese Bohai Sea, which offers significant potential for meteorological applications and climate studies in this region.

  14. The Relative Importance of Random Error and Observation Frequency in Detecting Trends in Upper Tropospheric Water Vapor

    Science.gov (United States)

    Whiteman, David N.; Vermeesch, Kevin C.; Oman, Luke D.; Weatherhead, Elizabeth C.

    2011-01-01

    Recent published work assessed the amount of time to detect trends in atmospheric water vapor over the coming century. We address the same question and conclude that under the most optimistic scenarios and assuming perfect data (i.e., observations with no measurement uncertainty) the time to detect trends will be at least 12 years at approximately 200 hPa in the upper troposphere. Our times to detect trends are therefore shorter than those recently reported and this difference is affected by data sources used, method of processing the data, geographic location and pressure level in the atmosphere where the analyses were performed. We then consider the question of how instrumental uncertainty plays into the assessment of time to detect trends. We conclude that due to the high natural variability in atmospheric water vapor, the amount of time to detect trends in the upper troposphere is relatively insensitive to instrumental random uncertainty and that it is much more important to increase the frequency of measurement than to decrease the random error in the measurement. This is put in the context of international networks such as the Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) and the Network for the Detection of Atmospheric Composition Change (NDACC) that are tasked with developing time series of climate quality water vapor data.

  15. Feasibility of retrieving dust properties and total column water vapor from solar spectra measured using a lander camera on Mars

    Science.gov (United States)

    Manago, Naohiro; Noguchi, Katsuyuki; Hashimoto, George L.; Senshu, Hiroki; Otobe, Naohito; Suzuki, Makoto; Kuze, Hiroaki

    2017-12-01

    Dust and water vapor are important constituents in the Martian atmosphere, exerting significant influence on the heat balance of the atmosphere and surface. We have developed a method to retrieve optical and physical properties of Martian dust from spectral intensities of direct and scattered solar radiation to be measured using a multi-wavelength environmental camera onboard a Mars lander. Martian dust is assumed to be composed of silicate-like substrate and hematite-like inclusion, having spheroidal shape with a monomodal gamma size distribution. Error analysis based on simulated data reveals that appropriate combinations of three bands centered at 450, 550, and 675 nm wavelengths and 4 scattering angles of 3°, 10°, 50°, and 120° lead to good retrieval of four dust parameters, namely, aerosol optical depth, effective radius and variance of size distribution, and volume mixing ratio of hematite. Retrieval error increases when some of the observational parameters such as color ratio or aureole are omitted from the retrieval. Also, the capability of retrieving total column water vapor is examined through observations of direct and scattered solar radiation intensities at 925, 935, and 972 nm. The simulation and error analysis presented here will be useful for designing an environmental camera that can elucidate the dust and water vapor properties in a future Mars lander mission.

  16. Search for water vapor in the high-resolution transmission spectrum of HD 189733b in the visible

    Science.gov (United States)

    Allart, R.; Lovis, C.; Pino, L.; Wyttenbach, A.; Ehrenreich, D.; Pepe, F.

    2017-10-01

    Context. Ground-based telescopes equipped with state-of-the-art spectrographs are able to obtain high-resolution transmission and emission spectra of exoplanets that probe the structure and composition of their atmospheres. Various atomic and molecular species, such as Na, CO, H2O have been already detected in a number of hot Jupiters. Molecular species have been observed only in the near-infrared while atomic species have been observed in the visible. In particular, the detection and abundance determination of water vapor bring important constraints to the planet formation process. Aims: We aim to search for water vapor in the atmosphere of the exoplanet HD 189733b using a high-resolution transmission spectrum in the visible obtained with HARPS. Methods: We used the atmospheric transmission code Molecfit to correct for telluric absorption features. Then we computed the high-resolution transmission spectrum of the planet using three transit datasets. We finally searched for water vapor absorption in the water band around 6500 Å using a cross-correlation technique that combines the signal of 600-900 individual lines. Results: Telluric features are corrected to the noise level. We place a 5-σ upper limit of 100 ppm on the strength of the 6500 Å water vapor band. The 1-σ precision of 20 ppm on the transmission spectrum demonstrates that space-like sensitivity can be achieved from the ground, even for a molecule that is a strong telluric absorber. Conclusions: This approach opens new possibilites for the detection of various atomic and molecular species with future instruments such as ESPRESSO at the VLT. Extrapolating from our results, we show that only one transit with ESPRESSO would be sufficient to detect water vapor on HD 189733b-like hot Jupiter with a cloud-free atmosphere. Upcoming near-IR spectrographs will be even more efficient and sensitive to a wider range of molecular species. Moreover, the detection of the same molecular species in different bands (e

  17. Measurement of turbulent water vapor fluxes using a lightweight unmanned aerial vehicle system

    Directory of Open Access Journals (Sweden)

    R. M. Thomas

    2012-01-01

    Full Text Available We present here the first application of a lightweight unmanned aerial vehicle (UAV system designed to measure turbulent properties and vertical latent heat fluxes (λE. Such measurements are crucial to improve our understanding of linkages between surface moisture supply and boundary layer clouds and phenomena such as atmospheric rivers. The application of UAVs allows for measurements on spatial scales complimentary to satellite, aircraft, and tower derived fluxes. Key system components are: a turbulent gust probe; a fast response water vapor sensor; an inertial navigation system (INS coupled to global positioning system (GPS; and a 100 Hz data logging system. We present measurements made in the continental boundary layer at the National Aeronautics and Space Administration (NASA Dryden Research Flight Facility located in the Mojave Desert. Two flights consisting of several horizontal straight flux run legs up to ten kilometers in length and between 330 and 930 m above ground level (m a.g.l. are compared to measurement from a surface tower. Surface measured λE ranged from −53 W m−2 to 41 W m−2, and the application of a Butterworth High Pass Filter (HPF to the datasets improved agreement to within +/−12 W m−2 for 86% of flux runs, by removing improperly sampled low frequency flux contributions. This result, along with power and co-spectral comparisons and consideration of the differing spatial scales indicates the system is able to resolve vertical fluxes for the measurement conditions encountered. Challenges remain, and the outcome of these measurements will be used to inform future sampling strategies and further system development.

  18. Modeling Insights into Deuterium Excess as an Indicator of Water Vapor Source Conditions

    Science.gov (United States)

    Lewis, Sophie C.; Legrande, Allegra Nicole; Kelley, Maxwell; Schmidt, Gavin A.

    2013-01-01

    Deuterium excess (d) is interpreted in conventional paleoclimate reconstructions as a tracer of oceanic source region conditions, such as temperature, where precipitation originates. Previous studies have adopted co-isotopic approaches to estimate past changes in both site and oceanic source temperatures for ice core sites using empirical relationships derived from conceptual distillation models, particularly Mixed Cloud Isotopic Models (MCIMs). However, the relationship between d and oceanic surface conditions remains unclear in past contexts. We investigate this climate-isotope relationship for sites in Greenland and Antarctica using multiple simulations of the water isotope-enabled Goddard Institute for Space Studies (GISS) ModelE-R general circulation model and apply a novel suite of model vapor source distribution (VSD) tracers to assess d as a proxy for source temperature variability under a range of climatic conditions. Simulated average source temperatures determined by the VSDs are compared to synthetic source temperature estimates calculated using MCIM equations linking d to source region conditions. We show that although deuterium excess is generally a faithful tracer of source temperatures as estimated by the MCIM approach, large discrepancies in the isotope-climate relationship occur around Greenland during the Last Glacial Maximum simulation, when precipitation seasonality and moisture source regions were notably different from present. This identified sensitivity in d as a source temperature proxy suggests that quantitative climate reconstructions from deuterium excess should be treated with caution for some sites when boundary conditions are significantly different from the present day. Also, the exclusion of the influence of humidity and other evaporative source changes in MCIM regressions may be a limitation of quantifying source temperature fluctuations from deuterium excess in some instances.

  19. Importance of depth and intensity of convection on the isotopic composition of water vapor as seen from IASI and TES δD observations

    Science.gov (United States)

    Lacour, Jean-Lionel; Risi, Camille; Worden, John; Clerbaux, Cathy; Coheur, Pierre-François

    2018-01-01

    We use tropical observations of the water vapor isotopic composition, derived from IASI and TES spaceborne measurements, to show that the isotopic composition of water vapor in the free troposphere is sensitive to both the depth and the intensity of convection. We find that for any given precipitation intensity, vapor associated with deep convection is isotopically depleted relative to vapor associated with shallow convection. The intensity of precipitation also plays a role as for any given depth of convection, the relative enrichment of water vapor decreases as the intensity of precipitation increases. Shallow convection, via the uplifting of enriched boundary layer air into the free troposphere and the convective detrainment, enriches the free troposphere. In contrast, deep convection is associated with processes that deplete the water vapor in the free troposphere, such as rain re-evaporation. The results of this study allow for a better identification of the parameters controlling the isotopic composition of the free troposphere and indicate that the isotopic composition of water vapor can be used to evaluate the relative contributions of shallow and deep convection in global models.

  20. Quantification of total iodine in intact granular starches of different botanical origin exposed to iodine vapor at various water activities.

    Science.gov (United States)

    Manion, Bruce; Ye, Mei; Holbein, Bruce E; Seetharaman, Koushik

    2011-11-08

    Iodine has been used as an effective tool for studying both the structure and composition of dispersed starch and starch granules. In addition to being employed to assess relative amylose contents for starch samples, it has been used to look at the molecular mobility of the glucose polymers within intact starch granules based on exposure to iodine vapor equilibrated at different water activities. Starches of different botanical origin including corn, high amylose corn, waxy corn, potato, waxy potato, tapioca, wheat, rice, waxy rice, chick pea and mung bean were equilibrated to 0.33, 0.75, 0.97 water activities, exposed to iodine vapor and then absorbance spectra and LAB color were determined. In addition, a new iodine quantification method sensitive to <0.1% iodine (w/w) was employed to measure bound iodine within intact granular starch. Amylose content, particle size distribution of granules, and the density of the starch were also determined to explore whether high levels of long linear glucose chains and the surface area-to-volume ratio were important factors relating to the granular iodine binding. Results showed, in all cases, starches complexed more iodine as water content increased and waxy starches bound less iodine than their normal starch counterparts. However, much more bound iodine could be measured chemically with waxy starches than was expected based on colorimetric determination. Surface area appeared to be a factor as smaller rice and waxy rice starch granules complexed more iodine, while the larger potato and waxy potato granules complexed less than would be expected based on measured amylose contents. Corn, high amylose corn, and wheat, known to have starch granules with extensive surface pores, bound higher levels of iodine suggesting pores and channels may be an important factor giving iodine vapor greater access to bind within the granules. Exposing iodine vapor to moisture-equilibrated native starches is an effective tool to explore starch

  1. Effects of pulsed and oscillatory flow on water vapor removal from a laboratory soil column. Final report, November 1993

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, Katherine Elizabeth [New Mexico State Univ., Las Cruces, NM (United States)

    1993-05-01

    Subsurface contamination by volatile organic contaminants (VOC`s) in the vadose zone and groundwater is primarily due to leaking underground storage tanks and industrial spills. Soil vapor extraction is a technique that is being used successfully to remove VOC`s from the subsurface. A flow of air is established through the soil to remove the vapor phase component of the contaminant. Soil vapor extraction will initially remove high levels of contaminant that is already present in the macropores. The concentration will start to decline as the removal from the soil matrix becomes limited by diffusion of contaminant from regions away from the air flow paths. This study examines potential methods of overcoming the diffusion limitation by adding an oscillatory component to the steady air flow and by pulsed flow, which involves turning air flow on and off at predetermined intervals. The study considered only the removal of water from the soil to try to establish general vapor behavior in the soil under the imposed conditions. Based on a statistical analysis, both the oscillatory and pulsed flow showed an improved water removal rate over the steady state flow. The effect of oscillatory flow was only examined at higher frequencies. The literature indicates that oscillations at lower frequencies may be more effective. Pulsed flow showed the most efficient removal of water compared to steady state conditions. The pulsed flow was most efficient because rather than reducing the diffusion limitation, the system would shut down and wait for diffusion to occur. This optimizes energy consumption, but does not reduce treatment time. The oscillatory flow actually reduced the diffusion limitation within the column which could result in a shorter treatment time.

  2. Water vapor pressure over molten KH2PO4 and demonstration of water electrolysis at ∼300ºC

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Nikiforov, Aleksey Valerievich; Petrushina, Irina

    2016-01-01

    with platinum electrodes and the electrolyte melt). The formation of mixtures of hydrogen and oxygen gases as well as the water vapor was detected by Raman spectroscopy. In this way it was demonstrated that water is present in the new electrolyte: molten KH2PO4 can be split by electrolysis via the reaction 2H2O......—H2O. The water vapor pressure above the melt, when contained in a closed ampoule, was determined quantitatively vs. temperature by use of Raman spectroscopy with methane or hydrogen gas as an internal calibration standard, using newly established relative ratios of Raman scattering cross sections...... of hydrogen-bonding has a high affinity for remaining in the melt. The formed hydrogen and oxygen gasses were detected by means of the characteristic Raman gas-phase spectra....

  3. Validation of MIPAS IMK-IAA Temperature, Water Vapor, and Ozone Profiles with MOHAVE-2009 Campaign Measurements

    Science.gov (United States)

    Stiller, Gabrielle; Kiefer, M.; Eckert, E.; von Clarmann, T.; Kellmann, S.; Garcia-Comas, M.; Funke, B.; Leblanc, T.; Fetzer, E.; Froidevaux, L.; hide

    2012-01-01

    MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK) and CSIC, Instituto de Astrofisica de Andalucia (IAA) and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MIPAS measurements were validated regarding any potential biases of the profiles, and with respect to their precision estimates. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radiosondes, ozonesondes, frost point hygrometers, lidars, microwave radiometers and Fourier transform infrared (FTIR) spectrometers. For MIPAS temperatures (version V4O_T_204), no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. These findings confirm earlier comparisons of MIPAS temperatures to ECMWF data which revealed similar differences. Above 12 km up to 45 km, MIPAS water vapor (version V4O_H2O_203) is well within 10% of the data of all correlative instruments. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40% around 10 km (or 5 km below the tropopause), but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O_O3_202) has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution. No further

  4. On the cross-sensitivity between water vapor mixing ratio and stable isotope measurements of in-situ analyzers

    KAUST Repository

    Parkes, Stephen

    2015-04-01

    In recent years there has been an increasing amount of water vapor stable isotope data collected using in-situ instrumentation. A number of papers have characterized the performance of these in-situ analyzers and suggested methods for calibrating raw measurements. The cross-sensitivity of the isotopic measurements on the mixing ratio has been shown to be a major uncertainty and a variety of techniques have been suggested to characterize this inaccuracy. However, most of these are based on relating isotopic ratios to water vapor mixing ratios from in-situ analyzers when the mixing ratio is varied and the isotopic composition kept constant. An additional correction for the span of the isotopic ratio scale is then applied by measuring different isotopic standards. Here we argue that the water vapor cross-sensitivity arises from different instrument responses (span and offset) of the parent H2O isotope and the heavier isotopes, rather than spectral overlap that could cause a true variation in the isotopic ratio with mixing ratio. This is especially relevant for commercial laser optical instruments where absorption lines are well resolved. Thus, the cross-sensitivity determined using more conventional techniques is dependent on the isotopic ratio of the standard used for the characterization, although errors are expected to be small. Consequently, the cross-sensitivity should be determined by characterizing the span and zero offset of each isotope mixing ratio. In fact, this technique makes the span correction for the isotopic ratio redundant. In this work we model the impact of changes in the span and offset of the heavy and light isotopes and illustrate the impact on the cross-sensitivity of the isotopic ratios on water vapor. This clearly shows the importance of determining the zero offset for the two isotopes. The cross-sensitivity of the isotopic ratios on water vapor is then characterized by determining the instrument response for the individual isotopes for a

  5. Validation of MIPAS IMK/IAA temperature, water vapor, and ozone profiles with MOHAVE-2009 campaign measurements

    Directory of Open Access Journals (Sweden)

    G. P. Stiller

    2012-02-01

    Full Text Available MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT, Institute for Meteorology and Climate Research (IMK and CSIC, Instituto de Astrofísica de Andalucía (IAA and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MIPAS measurements were validated regarding any potential biases of the profiles, and with respect to their precision estimates. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radiosondes, ozonesondes, frost point hygrometers, lidars, microwave radiometers and Fourier transform infra-red (FTIR spectrometers. For MIPAS temperatures (version V4O_T_204, no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. These findings confirm earlier comparisons of MIPAS temperatures to ECMWF data which revealed similar differences. Above 12 km up to 45 km, MIPAS water vapor (version V4O_H2O_203 is well within 10% of the data of all correlative instruments. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40% around 10 km (or 5 km below the tropopause, but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O_O3_202 has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution

  6. Photocatalytic oxidation of toluene in presence of water vapor using sol-gel synthesized N-doped TiO2

    Science.gov (United States)

    Van Sau, Nguyen; An, Ngo Thanh; Long, Nguyen Quang

    2017-09-01

    Toluene removal by photocatalytic oxidation in presence of water vapor was investigated on N-doped TiO2. The photocatalyst was prepared by a sol-gel method and characterized by various techniques. The conversion of toluene by photocatalytic oxidation in the presence of water vapor was reported at different reaction conditions, such as various reaction temperatures, various toluene/ water vapor concentrations. By using Langmuir- Hinshelwood model the activation energy (Ea) of the reaction of 1.33 kcal/mol was obtained. The heat of toluene adsorption and the heat of water vapor adsorption on the N-doped TiO2 catalyst were approximately -3.47 kcal/mol and -3.30 kcal/mol, respectively.

  7. AMSR-MODIS Boundary Layer Water Vapor L3 Daily 1 degree x 1 degree V1 (AMDBLWV) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides an estimate the marine boundary layer water vapor beneath uniform cloud fields. Microwave radiometry from AMSR-E and AMSR-2 provides the total...

  8. AMSR-MODIS Boundary Layer Water Vapor L3 Monthly 1 degree x 1 degree V1 (AMMBLWV) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides an estimate the marine boundary layer water vapor beneath uniform cloud fields. Microwave radiometry from AMSR-E and AMSR-2 provides the total...

  9. HIRDLS/Aura Level 3 Water Vapor (H2O) 1deg Lat Zonal Fourier Coefficients V007 (H3ZFCH2O) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients" version 7 data product (H3ZFCH2O) contains the entire mission (~3 years) of HIRDLS data...

  10. MODIS/Terra Aerosol, Cloud and Water Vapor Subset 5-Min L2 Swath 5km and 10km V005

    Data.gov (United States)

    National Aeronautics and Space Administration — MODATML2 contains a selection of the most useful atmosphere Level 2 aerosol, cloud and water vapor parameters at 5 and 10km spatial resolution. Native 1km cloud,...

  11. SCAMS/Nimbus-6 Level 2 Water Vapor and Temperature, as well as Antenna and Brightness Temperature V001 (SCAMSN6L2) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The Nimbus-6 Scanning Microwave Spectrometer (SCAMS) Level 2 data product contains water vapor and temperature profiles, as well as antenna and brightness...

  12. MODIS/Terra Total Precipitable Water Vapor 5-Min L2 Swath 1km and 5km V5.1

    Data.gov (United States)

    National Aeronautics and Space Administration — This Level 2 data collection contains derived precipitable column water vapor amounts, during daytime using a near-infrared over clear land areas and above clouds...

  13. GOZCARDS Source Water Vapor 1 month L3 10 degree Zonal Means on a Vertical Pressure Grid V1 (GozSmlpH2O) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOZCARDS Source Data for Water Vapor 1 month L3 10 degree Zonal Averages on a Vertical Pressure Grid product (GozSmlpH2O) contains zonal means and related...

  14. Interaction of binary cuprates with oxygen and water vapor at temperatures of 200-400°C

    Science.gov (United States)

    Bobylev, I. B.; Naumov, S. V.; Zyuzeva, N. A.

    2013-08-01

    Interaction of binary cuprates with oxygen and water vapor at T = 200-400°C has been studied. It has been established that only compounds containing oxygen vacancy chains in their structure can absorb oxygen and moisture from annealing atmosphere. Absorption of oxygen brings about decrease in the lattice parameters while embedding of OH- groups leads to their growth. In contrast to YBa2Cu3O y , binary cuprates do not undergo phase transitions in interaction with the atmosphere. Saturation with water and formation of oxyhydroxides is followed by their hydrolytic decomposition involving formation of simpler oxides and hydroxides.

  15. Treatment of Produced Waters Using a Surfactant Modified Zeolite/Vapor Phase Bioreactor System

    Energy Technology Data Exchange (ETDEWEB)

    Soondong Kwon; Elaine B. Darby; Li-Jung Chen; Lynn E. Katz; Kerry A. Kinney; R. S. Bowman; E. J. Sullivan

    2005-03-11

    second residence time, the GAC bed reduced peak contaminant concentrations by 97%. After the initial peak, the inlet VOC concentration in the SMZ regeneration gas stream drops exponentially with time. During this period, the contaminants on the GAC subsequently desorbed at a nearly steady rate over the next 45 hours resulting in a relatively steady effluent concentration of approximately 25 ppm{sub v}. This lower concentration is readily degradable by a downstream vapor phase biofilter (VPB) and the steady nature of the feed stream will prevent the biomass in the VPB from enduring starvation conditions between SMZ regeneration cycles. Repetitive sorption and desorption cycles that would be expected in the field were also investigated. It was determined that although the GAC initially lost some VOC sorption capacity, the adsorption and desorption profiles stabilized after approximately 6 cycles indicating that a GAC bed should be suitable for continuous operation. In preparation for the pilot field testing of the SMZ/VPB system, design, ''in-house'' construction and testing of the field system were completed during this project period. The design of the SMZ system for the pilot test was based on previous investigations by the PI's in Wyoming, 2002 and on analyses of the produced water at the field site in New Mexico. The field tests are scheduled for summer, 2005. A cost survey, feasibility of application and cost analyses were completed to investigate the long term effectiveness of the SMZ/VPB system as a method of treating produced water for re-use. Several factors were investigated, including: current costs to treat and dispose of produced water, end-use water quality requirements, and state and federal permitting requirements.

  16. Response to the Comment on Paper 'Water vapor Enhancement of Rates of Peroxy Radical Reactions', Int. J. Chem. Kinetics, 47, 395, 2015

    Energy Technology Data Exchange (ETDEWEB)

    Kumbhani, Sambhav R.; Cline, Taylor S.; Killian, Marie C.; Clark, Jared M.; Keeton, William J.; Hansen, Lee D.; Shirts, Randall B.; Robichaud, David J.; Hansen, Jaron C.

    2016-07-01

    Comments provided here aid in understanding the effect of water vapor on the rate of the self-reaction of HOCH2CH2O2 recently reported by Kumbhani et al. [1] Kumbhani et al. asserts that water vapor increases the rate of the HOCH2CH2O2 self-reaction by formation of an HOCH2CH2O2-H2O complex.

  17. EFFECT OF NON-DARCY FLOW COEFFICIENT VARIATION DUE TO WATER VAPORIZATION ON WELL PRODUCTIVITY OF GAS CONDENSATE RESERVOIRS

    Directory of Open Access Journals (Sweden)

    E. Sheikhi

    2015-03-01

    Full Text Available Abstract Well productivity of gas condensate reservoirs is highly affected by near-wellbore phenomena. Inertial force resulting from convective acceleration of fluid particles in the medium, as well as viscous force, determines the flow of gas through porous media at high velocity. Pressure drop builds up the molar content of water in gas by water vaporization in the near-wellbore region, which means a drop in connate water saturation. Given that the inertial force is a function of the non-Darcy coefficient, β, which itself depends upon connate water saturation, this can ultimately lessen the non-Darcy component of the pressure drop and therefore inertial forces, leading to improvement of well deliverability. Currently, no physically relevant model takes into account the non-Darcian flow coefficient variation due to this phenomenon. This paper utilizes a single-well compositional simulation to exhibit how water vaporization could compensate for the effect of inertia on well productivity of gas condensate reservoirs.

  18. Crack-free yttria stabilized zirconia thin films by aerosol assisted chemical vapor deposition: Influence of water and carrier gas

    Energy Technology Data Exchange (ETDEWEB)

    Schlupp, M.V.F., E-mail: Meike.Schlupp@mat.ethz.ch [Nonmetallic Inorganic Materials, ETH Zuerich, Wolfgang-Pauli-Str. 10, 8093 Zuerich (Switzerland); Binder, S.; Martynczuk, J.; Prestat, M. [Nonmetallic Inorganic Materials, ETH Zuerich, Wolfgang-Pauli-Str. 10, 8093 Zuerich (Switzerland); Gauckler, L.J. [Nonmetallic Inorganic Materials, ETH Zuerich, Wolfgang-Pauli-Str. 10, 8093 Zuerich (Switzerland); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2012-11-01

    Yttria stabilized zirconia thin films are deposited on silicon single crystal substrates by aerosol assisted chemical vapor deposition from precursor solutions of zirconium and yttrium 2,4-pentanedionate in ethanol. Continuous films are obtained using pure oxygen, pure nitrogen, or mixtures of both as carrier gas. In the simultaneous presence of water and oxygen, crack formation is observed for films deposited at intermediate substrate temperatures (450 Degree-Sign C), while those deposited at low (300 Degree-Sign C) and high (600 Degree-Sign C) temperatures remain crack-free. Crack-free films can be deposited at 450 Degree-Sign C in a water-free setting, or in the presence of water using pure nitrogen as carrier gas. The addition of water to the precursor solutions also significantly reduces film growth rates. - Highlights: Black-Right-Pointing-Pointer Thin film deposition by aerosol assisted chemical vapor deposition (AA-CVD) Black-Right-Pointing-Pointer Yttria stabilized zirconia (YSZ) thin films deposited between 300 Degree-Sign C and 600 Degree-Sign C Black-Right-Pointing-Pointer Water decreases growth rates and leads to crack formation in AA-CVD of YSZ. Black-Right-Pointing-Pointer Crack-free YSZ thin films deposited using oxygen and/or nitrogen as carrier gas Black-Right-Pointing-Pointer YSZ thin films deposited by AA-CVD show low shrinkage on annealing at 1000 Degree-Sign C.

  19. Contribution to vapor generation-inductively coupled plasma spectrometric techniques for determination of sulfide in water samples.

    Science.gov (United States)

    Cmelík, Jirí; Machát, Jirí; Otruba, Vítezslav; Kanický, Viktor

    2010-03-15

    Vapor generation-inductively coupled plasma-optical emission spectrometry was used for the determination of sulfide in water samples preserved by the addition of a zinc acetate and sodium hydroxide solution. Hydrogen sulfide and acid-volatile sulfides were transformed, by acidification, to a gaseous phase in a vapor generator and subsequently detected by inductively coupled plasma optical emission spectrometry. Compounds interfering with iodometric titration and spectrophotometric determination were examined as potential chemical interferents. The proposed method provides results comparable to iodometric titration in the tested concentration range 0.06-22.0 mg L(-1). Limit of detection for the determination of hydrogen sulfide by this method is 0.03 mg L(-1). Copyright (c) 2009 Elsevier B.V. All rights reserved.

  20. A visual water vapor photonic crystal sensor with PVA/SiO2 opal structure

    Science.gov (United States)

    Yang, Haowei; Pan, Lei; Han, Yingping; Ma, Lihua; Li, Yao; Xu, Hongbo; Zhao, Jiupeng

    2017-11-01

    In study, we proposed a simple yet fast optical sensing motif based on thimbleful of polyvinyl alcohol (PVA) infiltrated photonic crystal (PC), which allows for high efficiency in vapor sensing through changes in their inter-layer space. Linear response to a broad dynamic range of vapor concentration was realized. Ultrafast response time (<1 s) and excellent recyclability were also demonstrated. Selective response to a vapor was exhibited, reflecting well the characteristic sorption properties of PVA, with which colorimetric reporting was readily achieved. These substantial improvements in performance are attributed to the efficacy of signal transduction and the enhanced signal transduction because of thimbleful PVA infiltrated space between adjacent SiO2 nanospheres.

  1. Emission from water vapor and absorption from other gases at 5-7.5 μm in Spitzer-IRS Spectra Of Protoplanetary Disks

    Energy Technology Data Exchange (ETDEWEB)

    Sargent, B. A. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Forrest, W.; Watson, Dan M.; Kim, K. H.; Richter, I.; Tayrien, C. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); D' Alessio, P.; Calvet, N. [Department of Astronomy, The University of Michigan, 500 Church Street, 830 Dennison Building, Ann Arbor, MI 48109 (United States); Furlan, E. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Green, J. [Department of Astronomy, University of Texas, 1 University Station, Austin, TX 78712 (United States); Pontoppidan, K., E-mail: baspci@rit.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2014-09-10

    We present spectra of 13 T Tauri stars in the Taurus-Auriga star-forming region showing emission in Spitzer Space Telescope Infrared Spectrograph 5-7.5 μm spectra from water vapor and absorption from other gases in these stars' protoplanetary disks. Seven stars' spectra show an emission feature at 6.6 μm due to the ν{sub 2} = 1-0 bending mode of water vapor, with the shape of the spectrum suggesting water vapor temperatures >500 K, though some of these spectra also show indications of an absorption band, likely from another molecule. This water vapor emission contrasts with the absorption from warm water vapor seen in the spectrum of the FU Orionis star V1057 Cyg. The other 6 of the 13 stars have spectra showing a strong absorption band, peaking in strength at 5.6-5.7 μm, which for some is consistent with gaseous formaldehyde (H{sub 2}CO) and for others is consistent with gaseous formic acid (HCOOH). There are indications that some of these six stars may also have weak water vapor emission. Modeling of these stars' spectra suggests these gases are present in the inner few AU of their host disks, consistent with recent studies of infrared spectra showing gas in protoplanetary disks.

  2. Experimental Evaluation of Hybrid Distillation-Vapor Permeation Process for Efficient Ethanol Recovery from Ethanol-Water Mixtures

    Science.gov (United States)

    The energy demand of distillation-based systems for ethanol recovery and dehydration can be significant, particularly for dilute solutions [1]. An alternative separation process integrating vapor stripping with a vapor compression step and a vapor permeation membrane separation ...

  3. Evaluation of a Fully Automated Analyzer for Rapid Measurement of Water Vapor Sorption Isotherms for Applications in Soil Science

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

    2014-01-01

    The characterization and description of important soil processes such as water vapor transport, volatilization of pesticides, and hysteresis require accurate means for measuring the soil water characteristic (SWC) at low water potentials. Until recently, measurement of the SWC at low water...... sorption isotherms. In this technical note we present a comprehensive evaluation of the VSA instrument for a wide range of differently textured soils and discuss optimal measurement settings. The effects of operation mode, air-flow rate, sample pretreatment, test temperature, sample mass, and mass trigger...... point on resultant sorption isotherms were evaluated for a relative humidity range from 0.10 to 0.90. Both adsorption and desorption branches were measured for all soils within a reasonable time period (10 – 50 h). Sample masses larger than 3.5 g resulted in incomplete adsorption and desorption, while...

  4. Estimating trends in atmospheric water vapor and temperature time series over Germany

    Science.gov (United States)

    Alshawaf, Fadwa; Balidakis, Kyriakos; Dick, Galina; Heise, Stefan; Wickert, Jens

    2017-08-01

    Ground-based GNSS (Global Navigation Satellite System) has efficiently been used since the 1990s as a meteorological observing system. Recently scientists have used GNSS time series of precipitable water vapor (PWV) for climate research. In this work, we compare the temporal trends estimated from GNSS time series with those estimated from European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA-Interim) data and meteorological measurements. We aim to evaluate climate evolution in Germany by monitoring different atmospheric variables such as temperature and PWV. PWV time series were obtained by three methods: (1) estimated from ground-based GNSS observations using the method of precise point positioning, (2) inferred from ERA-Interim reanalysis data, and (3) determined based on daily in situ measurements of temperature and relative humidity. The other relevant atmospheric parameters are available from surface measurements of meteorological stations or derived from ERA-Interim. The trends are estimated using two methods: the first applies least squares to deseasonalized time series and the second uses the Theil-Sen estimator. The trends estimated at 113 GNSS sites, with 10 to 19 years temporal coverage, vary between -1.5 and 2.3 mm decade-1 with standard deviations below 0.25 mm decade-1. These results were validated by estimating the trends from ERA-Interim data over the same time windows, which show similar values. These values of the trend depend on the length and the variations of the time series. Therefore, to give a mean value of the PWV trend over Germany, we estimated the trends using ERA-Interim spanning from 1991 to 2016 (26 years) at 227 synoptic stations over Germany. The ERA-Interim data show positive PWV trends of 0.33 ± 0.06 mm decade-1 with standard errors below 0.03 mm decade-1. The increment in PWV varies between 4.5 and 6.5 % per degree Celsius rise in temperature, which is comparable to the theoretical rate of the Clausius

  5. Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

    Directory of Open Access Journals (Sweden)

    A. M. Makarieva

    2013-01-01

    Full Text Available Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 °C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power – this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

  6. CFD modelling of condensation process of water vapor in supersonic flows

    DEFF Research Database (Denmark)

    Wen, Chuang; Walther, Jens Honore; Yan, Yuying

    2016-01-01

    The condensation phenomenon of vapor plays an important role in various industries, such as the steam flow in turbines and refrigeration system. A mathematical model is developed to predict the spontaneous condensing phenomenon in the supersonic conditions using the nucleation and droplet growth...

  7. CFD modeling of condensation process of water vapor in supersonic flows

    DEFF Research Database (Denmark)

    Yang, Yan; Walther, Jens Honore; Yan, Yuying

    2017-01-01

    The condensation phenomenon of vapor plays an important role in various industries, such as the steam flow in turbines and refrigeration system. A mathematical model is developed to predict the spontaneous condensing phenomenon in the supersonic flows using the nucleation and droplet growth...

  8. Evaluation of continuous water vapor δD and δ18O measurements by off-axis integrated cavity output spectroscopy

    Directory of Open Access Journals (Sweden)

    L. J. Araguas-Araguas

    2012-08-01

    Full Text Available Recent commercially available laser spectroscopy systems enabled us to continuously and reliably measure the δD and δ18O of atmospheric water vapor. The use of this new technology is becoming popular because of its advantages over the conventional approach based on cold trap collection. These advantages include much higher temporal resolution/continuous monitoring and the ability to make direct measurements of both isotopes in the field. Here, we evaluate the accuracy and precision of the laser based water vapor isotope instrument through a comparison of measurements with those found using the conventional cold trap method. A commercially available water vapor isotope analyzer (WVIA with the vaporization system of a liquid water standard (Water Vapor Isotope Standard Source, WVISS from Los Gatos Research (LGR Inc. was used for this study. We found that the WVIA instrument can provide accurate results if (1 correction is applied for time-dependent isotope drift, (2 normalization to the VSMOW/SLAP scale is implemented, and (3 the water vapor concentration dependence of the isotopic ratio is also corrected. In addition, since the isotopic value of water vapor generated by the WVISS is also dependent on the concentration of water vapor, this effect must be considered to determine the true water vapor concentration effect on the resulting isotope measurement. To test our calibration procedure, continuous water vapor isotope measurements using both a laser instrument and a cold trap system were carried out at the IAEA Isotope Hydrology Laboratory in Vienna from August to December 2011. The calibrated isotopic values measured using the WVIA agree well with those obtained via the cold trap method. The standard deviation of the isotopic difference between both methods is about 1.4‰ for δD and 0.28‰ for δ18O. This precision allowed us to obtain reliable values for d-excess. The day-to-day variation of d-excess measured by WVIA also agrees well

  9. Estimating Sampling Biases and Measurement Uncertainties of AIRS-AMSU-A Temperature and Water Vapor Observations Using MERRA Reanalysis

    Science.gov (United States)

    Hearty, Thomas J.; Savtchenko, Andrey K.; Tian, Baijun; Fetzer, Eric; Yung, Yuk L.; Theobald, Michael; Vollmer, Bruce; Fishbein, Evan; Won, Young-In

    2014-01-01

    We use MERRA (Modern Era Retrospective-Analysis for Research Applications) temperature and water vapor data to estimate the sampling biases of climatologies derived from the AIRS/AMSU-A (Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A) suite of instruments. We separate the total sampling bias into temporal and instrumental components. The temporal component is caused by the AIRS/AMSU-A orbit and swath that are not able to sample all of time and space. The instrumental component is caused by scenes that prevent successful retrievals. The temporal sampling biases are generally smaller than the instrumental sampling biases except in regions with large diurnal variations, such as the boundary layer, where the temporal sampling biases of temperature can be +/- 2 K and water vapor can be 10% wet. The instrumental sampling biases are the main contributor to the total sampling biases and are mainly caused by clouds. They are up to 2 K cold and greater than 30% dry over mid-latitude storm tracks and tropical deep convective cloudy regions and up to 20% wet over stratus regions. However, other factors such as surface emissivity and temperature can also influence the instrumental sampling bias over deserts where the biases can be up to 1 K cold and 10% wet. Some instrumental sampling biases can vary seasonally and/or diurnally. We also estimate the combined measurement uncertainties of temperature and water vapor from AIRS/AMSU-A and MERRA by comparing similarly sampled climatologies from both data sets. The measurement differences are often larger than the sampling biases and have longitudinal variations.

  10. Determining water sources in the boundary layer from tall tower profiles of water vapor and surface water isotope ratios after a snowstorm in Colorado

    Science.gov (United States)

    Noone, D.; Risi, C.; Bailey, A.; Berkelhammer, M.; Brown, D. P.; Buenning, N.; Gregory, S.; Nusbaumer, J.; Schneider, D.; Sykes, J.; Vanderwende, B.; Wong, J.; Meillier, Y.; Wolfe, D.

    2013-02-01

    The D/H isotope ratio is used to attribute boundary layer humidity changes to the set of contributing fluxes for a case following a snowstorm in which a snow pack of about 10 cm vanished. Profiles of H2O and CO2 mixing ratio, D/H isotope ratio, and several thermodynamic properties were measured from the surface to 300 m every 15 min during four winter days near Boulder, Colorado. Coeval analysis of the D/H ratios and CO2 concentrations find these two variables to be complementary with the former being sensitive to daytime surface fluxes and the latter particularly indicative of nocturnal surface sources. Together they capture evidence for strong vertical mixing during the day, weaker mixing by turbulent bursts and low level jets within the nocturnal stable boundary layer during the night, and frost formation in the morning. The profiles are generally not well described with a gradient mixing line analysis because D/H ratios of the end members (i.e., surface fluxes and the free troposphere) evolve throughout the day which leads to large uncertainties in the estimate of the D/H ratio of surface water flux. A mass balance model is constructed for the snow pack, and constrained with observations to provide an optimal estimate of the partitioning of the surface water flux into contributions from sublimation, evaporation of melt water in the snow and evaporation from ponds. Results show that while vapor measurements are important in constraining surface fluxes, measurements of the source reservoirs (soil water, snow pack and standing liquid) offer stronger constraint on the surface water balance. Measurements of surface water are therefore essential in developing observational programs that seek to use isotopic data for flux attribution.

  11. Determining water sources in the boundary layer from tall tower profiles of water vapor and surface water isotope ratios after a snowstorm in Colorado

    Directory of Open Access Journals (Sweden)

    D. Noone

    2013-02-01

    Full Text Available The D/H isotope ratio is used to attribute boundary layer humidity changes to the set of contributing fluxes for a case following a snowstorm in which a snow pack of about 10 cm vanished. Profiles of H2O and CO2 mixing ratio, D/H isotope ratio, and several thermodynamic properties were measured from the surface to 300 m every 15 min during four winter days near Boulder, Colorado. Coeval analysis of the D/H ratios and CO2 concentrations find these two variables to be complementary with the former being sensitive to daytime surface fluxes and the latter particularly indicative of nocturnal surface sources. Together they capture evidence for strong vertical mixing during the day, weaker mixing by turbulent bursts and low level jets within the nocturnal stable boundary layer during the night, and frost formation in the morning. The profiles are generally not well described with a gradient mixing line analysis because D/H ratios of the end members (i.e., surface fluxes and the free troposphere evolve throughout the day which leads to large uncertainties in the estimate of the D/H ratio of surface water flux. A mass balance model is constructed for the snow pack, and constrained with observations to provide an optimal estimate of the partitioning of the surface water flux into contributions from sublimation, evaporation of melt water in the snow and evaporation from ponds. Results show that while vapor measurements are important in constraining surface fluxes, measurements of the source reservoirs (soil water, snow pack and standing liquid offer stronger constraint on the surface water balance. Measurements of surface water are therefore essential in developing observational programs that seek to use isotopic data for flux attribution.

  12. Subseasonal variability of water vapor in the upper stratosphere/lower mesosphere over Northern Europe in winter 2009/2010

    Science.gov (United States)

    Peters, D. H. W.; Hallgren, K.; Lübken, F.-J.; Hartogh, P.

    2014-07-01

    For the upper stratosphere and lower mesosphere (USLM) we used microwave spectrometer measurements of water vapor to investigate the cause of subseasonal variability over Northern Europe: at ALOMAR (Andenes, 69.3° N, 16.1° E), Northern Norway, and at the Leibniz Institute of Atmospheric Physics (Kühlungsborn, 54.2° N, 11.8° E), Northern Germany, for winter 2009/2010. The MERRA data set of NASA is applied to study the dynamical link between the local variability of H2O and transport in the USLM. Besides a slow increase in January and a stronger decrease in February and March 2010, episodes of significant increase and decrease of H2O were found over Northern Germany. These structural changes are in good agreement with MERRA which show similar patterns induced by a dominant conservative horizontal transport of H2O. Due to the strong negative meridional gradient and mixing barrier, higher values of water vapor have been observed outside the polar vortex and lower values inside. We found that the complex polar vortex evolution over Northern Germany during the minor stratospheric sudden warming (mSSW) in the beginning of December 2009 and the major warming (MSSW) at the end of January 2010, as well as between the two, fits well into this relationship. An episode of strong increase in water vapor over ALOMAR at about 55-60 km altitude was observed during the MSSW on the 27th of January 2010 resulting in a significant double peak in altitude. Based on MERRA data we show that this dual peak was caused by a relatively strong regional northward propagation of more moist air in the lower mesosphere. In the lower mesosphere strong polar intrusion of warm and moist air occurred mainly over Northern Europe resulting in a well-mixed polar anticyclone on the 30th of January. In comparison with observations the local maxima of H2O in MERRA are underestimated by approximately 1-2 ppmv. After the MSSW, the vertical descent rate of the MERRA reanalysis is half as much as the

  13. Development of a Local Mean Temperature Equation for GPS-Based Precipitable Water Vapor Over the Korean Peninsula

    Directory of Open Access Journals (Sweden)

    Juhyun Ha

    2006-12-01

    Full Text Available The Bevis' mean temperature equation (MTE is generally used in estimating Precipitable Water Vapor (PWV based on GPS measurements. Because the equation was derived from North American meteorological data, however, it may induce errors in PWV if the equation is applied to Korea which has different climate conditions. In this study, we developed a new MTE using local meteorological data. We compared PWVs from the new equation with those from the Bevis and two other local equations. The PWV differences from the four equations increase as a function of surface temperatures at the observation site, reaching up to 1˜3 mm.

  14. Mechanical signatures of degradation of the photovoltaic perovskite CH3NH3PbI3 upon water vapor exposure

    Science.gov (United States)

    Spina, Massimo; Karimi, Ayat; Andreoni, Wanda; Pignedoli, Carlo A.; Náfrádi, Bálint; Forró, László; Horváth, Endre

    2017-03-01

    We report on the mechanical properties of CH3NH3PbI3 photovoltaic perovskite measured by nanoindentation. The Young's modulus (E) of the pristine sample is 20.0 ± 1.5 GPa, while the hardness (H) is 1.0 ± 0.1 GPa. Upon extended exposure to water vapor, both quantities decrease dramatically and the sample changes color from silver-black to yellow. Calculations based on density functional theory support this trend in the mechanical response. Chemical treatment of the degraded crystal in methylammonium iodide solution recovers the color of the pristine sample and the values of E and H within 50%.

  15. Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer

    Science.gov (United States)

    Defrere, D.; Hinz, P.; Downey, E.; Boehm, M.; Danchi, W. C.; Durney, O.; Ertel, S.; Hill, J. M.; Hoffmann, W. F.; Mennesson, B.; hide

    2016-01-01

    The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feed forward approach to stabilize the path length fluctuations seen by the LBTI nuller uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current

  16. Sensitive limits on the abundance of cold water vapor in the DM Tauri protoplanetary disk

    DEFF Research Database (Denmark)

    Bergin, E. A.; Hogerheijde, M. R.; Brinch, Christian

    2010-01-01

    We performed a sensitive search for the ground-state emission lines of ortho- and para-water vapor in the DM Tau protoplanetary disk using the Herschel/HIFI instrument. No strong lines are detected down to 3σ levels in 0.5 km s-1 channels of 4.2 mK for the 110-101 line and 12.6 mK for the 111......, model calculations indicate that our sensitive limits on the line strengths preclude efficient desorption of water in the UV illuminated regions of the disk. We hypothesize that more than 95-99% of the water ice is locked up in coagulated grains that have settled to the midplane. Herschel is an ESA...

  17. Direct gas-solid carbonation of serpentinite residues in the absence and presence of water vapor: a feasibility study for carbon dioxide sequestration.

    Science.gov (United States)

    Veetil, Sanoopkumar Puthiya; Pasquier, Louis-César; Blais, Jean-François; Cecchi, Emmanuelle; Kentish, Sandra; Mercier, Guy

    2015-09-01

    Mineral carbonation of serpentinite mining residue offers an environmentally secure and permanent storage of carbon dioxide. The strategy of using readily available mining residue for the direct treatment of flue gas could improve the energy demand and economics of CO2 sequestration by avoiding the mineral extraction and separate CO2 capture steps. The present is a laboratory scale study to assess the possibility of CO2 fixation in serpentinite mining residues via direct gas-solid reaction. The degree of carbonation is measured both in the absence and presence of water vapor in a batch reactor. The gas used is a simulated gas mixture reproducing an average cement flue gas CO2 composition of 18 vol.% CO2. The reaction parameters considered are temperature, total gas pressure, time, and concentration of water vapor. In the absence of water vapor, the gas-solid carbonation of serpentinite mining residues is negligible, but the residues removed CO2 from the feed gas possibly due to reversible adsorption. The presence of small amount of water vapor enhances the gas-solid carbonation, but the measured rates are too low for practical application. The maximum CO2 fixation obtained is 0.07 g CO2 when reacting 1 g of residue at 200 °C and 25 barg (pCO2 ≈ 4.7) in a gas mixture containing 18 vol.% CO2 and 10 vol.% water vapor in 1 h. The fixation is likely surface limited and restricted due to poor gas-solid interaction. It was identified that both the relative humidity and carbon dioxide-water vapor ratio have a role in CO2 fixation regardless of the percentage of water vapor.

  18. Predicting Soil-Air and Soil-Water Transport Properties During Soil Vapor Extraction

    DEFF Research Database (Denmark)

    Poulsen, Tjalfe

    Increased application of in-situ technology for control and removal of volatile organic compounds (VOC) in the subsurface has made the understanding of soil physical properties and their impact upon contaminant transport even more important. Knowledge of contaminant transport is important when...... properties of undisturbed soil from more easily measurable soil properties are developed. The importance of soil properties with respect to contaminant migration during remediation by soil vapor extraction (SVE) in the unsaturated zone was investigated using numerical simulations....

  19. Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell during initial stage of shell expansion

    Directory of Open Access Journals (Sweden)

    Astafyeva Liudmila

    2011-01-01

    Full Text Available Abstract Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell, created under laser heating of nanoparticle in water, were theoretically investigated. Vapor shell expansion leads to decreasing up to one to two orders of magnitude in comparison with initial values of scattering and extinction of the radiation with wavelengths 532 and 633 nm by system while shell radius is increased up to value of about two radii of nanoparticle. Subsequent increasing of shell radius more than two radii of nanoparticle leads to rise of scattering and extinction properties of system over initial values. The significant decrease of radiation scattering and extinction by system of nanoparticle-vapor shell can be used for experimental detection of the energy threshold of vapor shell formation and investigation of the first stages of its expansion. PACS: 42.62.BE. 78.67. BF

  20. Ticosonde CFH at Costa Rica: A Seasonal Climatology of Tropical UT-LS Water Vapor and Inter-Comparisons with MLS and CALIPSO

    Science.gov (United States)

    Selkirk, Henry B.; Voemel, Holger; Avery, Melody; Rosenlof, Karen; Davis, Sean; Hurst, Dale; Schoeberl, Mark; Diaz, Jorge Andres; Morris, Gary

    2014-01-01

    Balloon sonde measurements of tropical water vapor using the Cryogenic Frostpoint Hygrometer were initiated in Costa Rica in July 2005 and have continued to the present day. Over the nine years through July 2014, the Ticosonde program has launched 174 CFH payloads, representing the longest-running and most extensive single-site balloon dataset for tropical water vapor. In this presentation we present a seasonal climatology for water vapor and ozone at Costa Rica and examine the frequency of upper tropospheric supersaturation with comparisons to cloud fraction and cloud ice water content observations from the Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) on the CALIPSO mission. We then make a critical comparison of these data to water vapor measurements from the MLS instrument on board Aura in light of recently published work for other sites. Finally, we examine time series of 2-km altitude averages in the upper troposphere-lower stratosphere at Costa Rica in light of anomalies and trends seen in various large-scale indices of tropical water vapor.

  1. Temporal Variations of Water Vapor in the Coma of 67P/Churyumov-Gerasimenko as Observed by Rosetta’s Alice FUV Spectrograph

    Science.gov (United States)

    Steffl, Andrew J.; Feaga, Lori M.; A'Hearn, Michael; Bertaux, Jean-Loup; Feldman, Paul D.; Keeney, Brian A.; Knight, Matthew M.; Medina, Richard; Noonan, John; Parker, Joel Wm.; Pineau, Jon; Schindhelm, Eric; Stern, S. Alan; Versteeg, Maarten H.; Vervack, Ronald J.; Weaver, Harold A.

    2017-10-01

    During the Rosetta mission, the Alice far-ultraviolet (FUV) imaging spectrograph obtained spatially-resolved spectra of the coma and nucleus of comet 67P/Churyumov-Gerasimenko over the wavelength range of 700-2050Å. Typically, Alice detected emissions from the neutral atomic daughter and granddaughter products (H, O, C, and S) of the primary molecular species in the coma: H2O, CO2, CO, and O2. However, during a six-month period centered near perihelion, Alice directly detected water vapor in absorption of sunlight reflected from the nucleus. We present here analyses of the water vapor column density as measured by the Alice FUV spectrograph. Alice is sensitive to water vapor at column densities greater than ~1016 cm-2 along the sum of the Sun-nucleus and nucleus-spacecraft lines of sight. Due to the excellent temporal coverage provided by the Alice instrument (exposures were typically obtained every 5-10 minutes), we are able to show variations of water vapor in the coma caused by the changing heliocentric distance of the comet, the comet’s ~12-hour rotation period, and short-term outbursts. We compare our water vapor column densities to those derived from other instruments aboard the Rosetta spacecraft and use models to estimate the water production rate.Rosetta is an ESA mission with contributions from its member states and NASA. The Alice team acknowledges continuing support from NASA’s Jet Propulsion Laboratory through contract 1336850 to the Southwest Research Institute.

  2. Determination of zenith hydrostatic delay and its impact on GNSS-derived integrated water vapor

    Science.gov (United States)

    Wang, Xiaoming; Zhang, Kefei; Wu, Suqin; He, Changyong; Cheng, Yingyan; Li, Xingxing

    2017-08-01

    Surface pressure is a necessary meteorological variable for the accurate determination of integrated water vapor (IWV) using Global Navigation Satellite System (GNSS). The lack of pressure observations is a big issue for the conversion of historical GNSS observations, which is a relatively new area of GNSS applications in climatology. Hence the use of the surface pressure derived from either a blind model (e.g., Global Pressure and Temperature 2 wet, GPT2w) or a global atmospheric reanalysis (e.g., ERA-Interim) becomes an important alternative solution. In this study, pressure derived from these two methods is compared against the pressure observed at 108 global GNSS stations at four epochs (00:00, 06:00, 12:00 and 18:00 UTC) each day for the period 2000-2013. Results show that a good accuracy is achieved from the GPT2w-derived pressure in the latitude band between -30 and 30° and the average value of 6 h root-mean-square errors (RMSEs) across all the stations in this region is 2.5 hPa. Correspondingly, an error of 5.8 mm and 0.9 kg m-2 in its resultant zenith hydrostatic delay (ZHD) and IWV is expected. However, for the stations located in the mid-latitude bands between -30 and -60° and between 30 and 60°, the mean value of the RMSEs is 7.3 hPa, and for the stations located in the high-latitude bands from -60 to -90° and from 60 to 90°, the mean value of the RMSEs is 9.9 hPa. The mean of the RMSEs of the ERA-Interim-derived pressure across at the selected 100 stations is 0.9 hPa, which will lead to an equivalent error of 2.1 mm and 0.3 kg m-2 in the ZHD and IWV, respectively, determined from this ERA-Interim-derived pressure. Results also show that the monthly IWV determined using pressure from ERA-Interim has a good accuracy - with a relative error of better than 3 % on a global scale; thus, the monthly IWV resulting from ERA-Interim-derived pressure has the potential to be used for climate studies, whilst the monthly IWV resulting from GPT2w

  3. Determination of zenith hydrostatic delay and its impact on GNSS-derived integrated water vapor

    Directory of Open Access Journals (Sweden)

    X. Wang

    2017-08-01

    Full Text Available Surface pressure is a necessary meteorological variable for the accurate determination of integrated water vapor (IWV using Global Navigation Satellite System (GNSS. The lack of pressure observations is a big issue for the conversion of historical GNSS observations, which is a relatively new area of GNSS applications in climatology. Hence the use of the surface pressure derived from either a blind model (e.g., Global Pressure and Temperature 2 wet, GPT2w or a global atmospheric reanalysis (e.g., ERA-Interim becomes an important alternative solution. In this study, pressure derived from these two methods is compared against the pressure observed at 108 global GNSS stations at four epochs (00:00, 06:00, 12:00 and 18:00 UTC each day for the period 2000–2013. Results show that a good accuracy is achieved from the GPT2w-derived pressure in the latitude band between −30 and 30° and the average value of 6 h root-mean-square errors (RMSEs across all the stations in this region is 2.5 hPa. Correspondingly, an error of 5.8 mm and 0.9 kg m−2 in its resultant zenith hydrostatic delay (ZHD and IWV is expected. However, for the stations located in the mid-latitude bands between −30 and −60° and between 30 and 60°, the mean value of the RMSEs is 7.3 hPa, and for the stations located in the high-latitude bands from −60 to −90° and from 60 to 90°, the mean value of the RMSEs is 9.9 hPa. The mean of the RMSEs of the ERA-Interim-derived pressure across at the selected 100 stations is 0.9 hPa, which will lead to an equivalent error of 2.1 mm and 0.3 kg m−2 in the ZHD and IWV, respectively, determined from this ERA-Interim-derived pressure. Results also show that the monthly IWV determined using pressure from ERA-Interim has a good accuracy − with a relative error of better than 3 % on a global scale; thus, the monthly IWV resulting from ERA-Interim-derived pressure has the potential to be used for climate studies

  4. A theoretical investigation on anomalous switching of single-stranded deoxyribonucleic acid (ssDNA) monolayers by water vapor

    Science.gov (United States)

    Zhao, Xin-Jun; Gao, Zhi-Fu; Jiang, Zhong-Ying

    2015-04-01

    In this paper, we use a molecular theory to study the anomalous switching of ssDNA monolayers. Here, both ssDNA-water and water-water hydrogen bonds and their explicit coupling to the ssDNA conformations are considered. We find that hydrogen bonding becomes a key element in inducing the anomalous switching of ssDNA monolayers. This finding accords well with the experimental observations. Based on our theoretical model, we predict that the anomalous switching induced by water vapor will be applicable to a wide range of hydrogen bonds polymers, and ssDNA-water hydrogen bonds and water-water hydrogen bonds hybridization will lead to the hydrogen-bond network formation of 3D ssDNA monolayers. Project supported by the National Natural Science Foundation of China (Grant Nos. 21264016, 11464047, and 21364016), the National Basic Research Program of China (Grant No. 2012CB821500), and the Natural Science Foundation of Xinjiang Uygur Autonomous Region, China (Grant No. 2013211A053).

  5. NUMERICAL SIMULATION OF THE INCOMPRESSIBLE TURBULENT FLOW OF A BINARY MIXTURE OF AIR-WATER VAPOR: APPLICATIONS IN DRYING PROCESS

    Directory of Open Access Journals (Sweden)

    P. S. B. Zdanski

    Full Text Available Abstract The present work deals with numerical simulation of the incompressible turbulent flow of a binary mixture air-water vapor inside channels. Calculations are performed using the RANS (Reynolds Average Navier-Stokes Equations formulation in addition to the standart k-ε turbulence model. The mathematical model is discretized by a finite difference scheme, being adopted second order accurate expressions for both convection and diffusion terms. The mesh arrangement is collocated and artificial dissipation terms are added to control the odd-even decoupling problem. The numerical scheme is applied to solve the flow of a binary mixture of air-water vapor inside plane channels and sudden expansions. The validation performed indicates that the present method reproduces satisfactorily the literature data for both concentration profiles and Sherwood number. Furthermore, the parametric analysis performed indicates that the drying process (wall mass flux is very sensitive to the flow parameters investigated, i.e., inlet flow velocity and channel expansion ratio.

  6. Accuracy of tropospheric and stratospheric water vapor measurements by the cryogenic frost point hygrometer: Instrumental details and observations

    Science.gov (United States)

    VöMel, H.; David, D. E.; Smith, K.

    2007-04-01

    The cryogenic frost point hygrometer (CFH), currently built at the University of Colorado, is a new balloon borne hygrometer, which is capable of continuously measuring water vapor between the surface and the middle stratosphere. The design is loosely based on the old NOAA/CMDL frost point hygrometer, with improved accuracy and a number of significant new features that overcome some limitations of the older instrument. The measurement uncertainty of the new instrument depends on altitude and ranges between less than 4% in the tropical lower troposphere to no more than 10% in the middle stratosphere at 28 km. In the tropopause region the uncertainty is less than 9%. This instrument is used routinely at several sites for validation of satellite measurements and process studies in the upper troposphere and lower stratosphere region. It has proved to be particularly well suited for dehydration observations in the tropical upper troposphere, because the effects of cloud contamination have been significantly reduced. Results of this instrument are compared with the old NOAA/CMDL hygrometer, the Russian Fluorescent Lyman Alpha Stratospheric Hygrometer, the Vaisala RS92, the AURA/MLS satellite instrument, a cloud lidar, the NOAA/CSD frost point hygrometer and the Harvard Lyman-alpha hygrometer, both of the later instruments flown on board the NASA WB-57F high-altitude research aircraft. These comparisons demonstrate the level of accuracy of tropospheric and stratospheric water vapor measurements made by this instrument and point to areas where more research and development are needed.

  7. Application of Evaporative Cooling for the Condensation of Water Vapors from a Flue Gas Waste Heat Boilers CCP

    Directory of Open Access Journals (Sweden)

    Galashov Nikolay

    2016-01-01

    Full Text Available The object of the study are boilers that burn organic fuel and the recovery boilers (RB of the combined cycle plant (CCP, which are al-so working on the products of the combustion of hydrocarbon fuels. The purpose of research is to find technologies that increase efficiency