WorldWideScience

Sample records for air surface temperature

  1. Sea surface temperature measurements with AIRS

    Science.gov (United States)

    Aumann, H.

    2003-01-01

    The comparison of global sea surface skin temperature derived from cloud-free AIRS super window channel at 2616 cm-1 (sst2616) with the Real-Time Global Sea Surface Temperature for September 2002 shows surprisingly small standard deviation of 0.44K.

  2. Global surface air temperatures - Update through 1987

    Science.gov (United States)

    Hansen, James; Lebedeff, Sergej

    1988-01-01

    Data from meteorological stations show that surface air temperatures in the 1980s are the warmest in the history of instrumental records. The four warmest years on record are all in the 1980s, with the warmest years in the analysis being 1981 and 1987. The rate of warming between the mid-1960s and the present is higher than that which occurrred in the previous period of rapid warming between the 1880s and 1940.

  3. Global trends of measured surface air temperature

    Science.gov (United States)

    Hansen, James; Lebedeff, Sergej

    1987-01-01

    The paper presents the results of surface air temperature measurements from available meteorological stations for the period of 1880-1985. It is shown that the network of meteorological stations is sufficient to yield reliable long-term, decadal, and interannual temperature changes for both the Northern Hemisphere and the Southern Hemisphere, despite the fact that most stations are located on the continents. The results indicate a global warming of about 0.5-0.7 C in the past century, with warming of similar magnitude in both hemispheres. A strong warming trend between 1965 and 1980 raised the global mean temperature in 1980 and 1981 to the highest level in the period of instrumental records. Selected graphs of the temperature change in each of the eight latitude zones are included.

  4. Monthly Near-Surface Air Temperature Averages

    Data.gov (United States)

    National Aeronautics and Space Administration — Global surface temperatures in 2010 tied 2005 as the warmest on record. The International Satellite Cloud Climatology Project (ISCCP) was established in 1982 as...

  5. Is Air Temperature Enough to Predict Lake Surface Temperature?

    Science.gov (United States)

    Piccolroaz, S.; Toffolon, M.; Majone, B.

    2014-12-01

    Lake surface water (LST) is a key factor that controls most of the physical and ecological processes occurring in lakes. Reliable estimates are especially important in the light of recent studies, which revealed that inland water bodies are highly sensitive to climate, and are rapidly warming throughout the world. However, an accurate estimation of LST usually requires a significant amount of information that is not always available. In this work, we present an application of air2water, a lumped model that simulates LST as a function of air temperature only. In addition, air2water allows for a qualitative evaluation of the depth of the epilimnion during the annual stratification cycle. The model consists in a simplification of the complete heat budget of the well-mixed surface layer, and has a few parameters (from 4 to 8 depending on the version) that summarize the role of the different heat flux components. Model calibration requires only air and water temperature data, possibly covering sufficiently long historical periods in order to capture inter-annual variability and long-term trends. During the calibration procedure, the information included in input data is retrieved to directly inform model parameters, which can be used to classify the thermal behavior of the lake. In order to investigate how thermal dynamics are related to morphological features, the model has been applied to 14 temperate lakes characterized by different morphological and hydrological conditions, by different sources of temperature data (buoys, satellite), and by variable frequency of acquisition. A good agreement between observed and simulated LST has been achieved, with a RMSE in the order of 1°C, which is fully comparable to the performances of more complex process-based models. This application allowed for a deeper understanding of the thermal response of lakes as a function of their morphology, as well as for specific analyses as for example the investigation of the exceptional

  6. Land surface air temperature retrieval from EOS-MODIS images

    OpenAIRE

    Niclòs Corts, Raquel; Valiente, José Antonio; Barberà, María Jesús; Caselles Miralles, Vicente

    2014-01-01

    The knowledge of the spatial and temporal patterns of Surface Air Temperature (SAT) is essential to monitor a region¿s climate and meteorology, quantify surface exchange processes, improve climatic and meteorological model results, and study health and economic impacts. This work analyzed correlations between SAT and geophysical land surface variables, Land Surface Temperature (LST) mainly, to establish operative techniques to obtain spatially-continuous land SAT maps from satellite data, unl...

  7. Surface air temperature variability in global climate models

    CERN Document Server

    Davy, Richard

    2012-01-01

    New results from the Coupled Model Inter-comparison Project phase 5 (CMIP5) and multiple global reanalysis datasets are used to investigate the relationship between the mean and standard deviation in the surface air temperature. A combination of a land-sea mask and orographic filter were used to investigate the geographic region with the strongest correlation and in all cases this was found to be for low-lying over-land locations. This result is consistent with the expectation that differences in the effective heat capacity of the atmosphere are an important factor in determining the surface air temperature response to forcing.

  8. Symmetric scaling properties in global surface air temperature anomalies

    Science.gov (United States)

    Varotsos, Costas A.; Efstathiou, Maria N.

    2015-08-01

    We have recently suggested "long-term memory" or internal long-range correlation within the time-series of land-surface air temperature (LSAT) anomalies in both hemispheres. For example, an increasing trend in the LSAT anomalies is followed by another one at a different time in a power-law fashion. However, our previous research was mainly focused on the overall long-term persistence, while in the present study, the upward and downward scaling dynamics of the LSAT anomalies are analysed, separately. Our results show that no significant fluctuation differences were found between the increments and decrements in LSAT anomalies, over the whole Earth and over each hemisphere, individually. On the contrary, the combination of land-surface air and sea-surface water temperature anomalies seemed to cause a departure from symmetry and the increments in the land and sea surface temperature anomalies appear to be more persistent than the decrements.

  9. Geomagnetic activity and polar surface air temperature variability

    Science.gov (United States)

    Seppälä, A.; Randall, C. E.; Clilverd, M. A.; Rozanov, E.; Rodger, C. J.

    2009-10-01

    Here we use the ERA-40 and ECMWF operational surface level air temperature data sets from 1957 to 2006 to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the A p index. Previous modeling work has suggested that NO x produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in surface air temperatures (SATs). We find that during winter months, polar SATs in years with high A p index are different than in years with low A p index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, depending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings (SSWs) are excluded. We take into account solar irradiance variations, unlike previous analyses of geomagnetic effects in ERA-40 and operational data. Although we cannot conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating wintertime surface air temperatures. We tested our SAT results against variation in the Quasi Biennial Oscillation, the El Niño Southern Oscillation and the Southern Annular Mode. The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode, and we cannot robustly exclude a chance linkage between sea surface temperature variability and geomagnetic activity.

  10. Climate Prediction Center (CPC) Global Land Surface Air Temperature Analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A station observation-based global land monthly mean surface air temperature dataset at 0.5 x 0.5 latitude-longitude resolution for the period from 1948 to the...

  11. Comparison of MODIS Land Surface Temperature and Air Temperature over the Continental USA Meteorological Stations

    Science.gov (United States)

    Zhang, Ping; Bounoua, Lahouari; Imhoff, Marc L.; Wolfe, Robert E.; Thome, Kurtis

    2014-01-01

    The National Land Cover Database (NLCD) Impervious Surface Area (ISA) and MODIS Land Surface Temperature (LST) are used in a spatial analysis to assess the surface-temperature-based urban heat island's (UHIS) signature on LST amplitude over the continental USA and to make comparisons to local air temperatures. Air-temperature-based UHIs (UHIA), calculated using the Global Historical Climatology Network (GHCN) daily air temperatures, are compared with UHIS for urban areas in different biomes during different seasons. NLCD ISA is used to define urban and rural temperatures and to stratify the sampling for LST and air temperatures. We find that the MODIS LST agrees well with observed air temperature during the nighttime, but tends to overestimate it during the daytime, especially during summer and in nonforested areas. The minimum air temperature analyses show that UHIs in forests have an average UHIA of 1 C during the summer. The UHIS, calculated from nighttime LST, has similar magnitude of 1-2 C. By contrast, the LSTs show a midday summer UHIS of 3-4 C for cities in forests, whereas the average summer UHIA calculated from maximum air temperature is close to 0 C. In addition, the LSTs and air temperatures difference between 2006 and 2011 are in agreement, albeit with different magnitude.

  12. Linking geomagnetic activity and polar surface air temperature variability

    Science.gov (United States)

    Seppala, Annika

    ERA-40 and ECMWF operational surface level air temperature (SAT) data sets from 1957 to 2006 were used to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the Ap index. Previous modelling work has suggested that NOx produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in polar SATs. We find that during winter months, ERA-40 and ECMWF polar SATs in years with high Ap index are different than in years with low Ap index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, de-pending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings are excluded. Solar irradiance variations were taken into account in the analysis. Although using the re-analysis and operational data sets it was not possible to conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating polar wintertime surface air temperature patterns. The SAT results were tested against variation in the Quasi Biennial Oscillation (QBO), the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode n (SAM). The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode (NAM) and we could not robustly exclude a chance linkage between sea surface temperature (SST) variability and geomagnetic activity. Examining the physical link between geomagnetic activity and polar surface temperature variability patterns using atmospheric models is an ongoing task.

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

    Directory of Open Access Journals (Sweden)

    Tanja Likso

    2006-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Tanja Likso

    2006-12-01

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

  15. Surface air temperature variability in global climate models

    OpenAIRE

    Davy, Richard; Esau, Igor

    2013-01-01

    New results from the Coupled Model Inter-comparison Project phase 5 (CMIP5) and multiple global reanalysis datasets are used to investigate the relationship between the mean and standard deviation in the surface air temperature. A combination of a land-sea mask and orographic filter were used to investigate the geographic region with the strongest correlation and in all cases this was found to be for low-lying over-land locations. This result is consistent with the expectation that difference...

  16. Estimation of surface air temperature over central and eastern Eurasia from MODIS land surface temperature

    International Nuclear Information System (INIS)

    Surface air temperature (Ta) is a critical variable in the energy and water cycle of the Earth–atmosphere system and is a key input element for hydrology and land surface models. This is a preliminary study to evaluate estimation of Ta from satellite remotely sensed land surface temperature (Ts) by using MODIS-Terra data over two Eurasia regions: northern China and fUSSR. High correlations are observed in both regions between station-measured Ta and MODIS Ts. The relationships between the maximum Ta and daytime Ts depend significantly on land cover types, but the minimum Ta and nighttime Ts have little dependence on the land cover types. The largest difference between maximum Ta and daytime Ts appears over the barren and sparsely vegetated area during the summer time. Using a linear regression method, the daily maximum Ta were estimated from 1 km resolution MODIS Ts under clear-sky conditions with coefficients calculated based on land cover types, while the minimum Ta were estimated without considering land cover types. The uncertainty, mean absolute error (MAE), of the estimated maximum Ta varies from 2.4 °C over closed shrublands to 3.2 °C over grasslands, and the MAE of the estimated minimum Ta is about 3.0 °C.

  17. Subseasonal variability of North American wintertime surface air temperature

    Science.gov (United States)

    Lin, Hai

    2015-09-01

    Using observational pentad data of the recent 34 Northern Hemisphere extended winters, subseasonal variability of surface air temperature (SAT) over North America is analyzed. The four leading modes of subseasonal SAT variability, that are identified with an empirical orthogonal function (EOF) analysis, account for about 60% of the total variance. The first (EOF1) and second (EOF2) modes are independent of other modes, and thus are likely controlled by distinct processes. The third (EOF3) and fourth (EOF4) modes, however, tend to have a phase shift to each other in space and time, indicating that part of their variability is related to a common process and represent a propagating pattern over North America. Lagged regression analysis is conducted to identify the precursors of large-scale atmospheric circulation for each mode a few pentads in advance, and to understand the processes that influence the subseasonal SAT variability and the predictability signal sources. EOF1 is found to be closely related to the Pacific-North American (PNA) circulation pattern and at least part of its variability is preceded by the East Asian cold surge. The cold surge leads to low-level convergence and enhanced convection in the tropical central Pacific which in turn induces the PNA. EOF2 tends to oscillate at a period of about 70 days, and is influenced by the low-frequency component of the Madden-Julian Oscillation (MJO). On the other hand, EOF3 and EOF4 are connected to the high-frequency part of the MJO which has a period range of 30-50 days. These findings would help understanding the mechanisms of subseasonal surface air temperature variability in North America and improving weather predictions on a subseasonal time scale.

  18. A Physically Based Spatial Expansion Algorithm for Surface Air Temperature and Humidity

    Directory of Open Access Journals (Sweden)

    Hongbo Su

    2013-01-01

    Full Text Available An algorithm was developed to expand the surface air temperature and air humidity to a larger spatial domain, based on the fact that the variation of surface air temperature and air humidity is controlled jointly by the local turbulence and the horizontal advection. This study proposed an algorithm which considers the advective driving force outside the thermal balance system and the turbulent driving force and radiant driving force inside the thermal balance system. The surface air temperature is determined by a combination of the surface observations and the regional land surface temperature observed from a satellite. The average absolute difference of the algorithm is 0.65 degree and 0.31 mb, respectively, for surface air temperature and humidity expansion, which provides a promising approach to downscale the two surface meteorological variables.

  19. Retrieval of sea surface air temperature from satellite data over Indian Ocean: An empirical approach

    Digital Repository Service at National Institute of Oceanography (India)

    Sathe, P.V.; Muraleedharan, P.M.

    the surface air temperature and surface humidity is analysed by fitting a polynomial between the two for different regions of the Indian Ocean in different seasons. Taking into account the variation in surface air temperatures, the Indian Ocean is split in 14...

  20. Air Temperature estimation from Land Surface temperature and solar Radiation parameters

    Science.gov (United States)

    Lazzarini, Michele; Eissa, Yehia; Marpu, Prashanth; Ghedira, Hosni

    2013-04-01

    Air Temperature (AirT) is a fundamental parameter in a wide range of applications such as climate change studies, weather forecast, energy balance modeling, efficiency of Photovoltaic (PV) solar cells, etc. Air temperature data are generally obtained through regular measurements from meteorological stations. The distribution of these stations is normally sparse, so the spatial pattern of this parameter cannot be accurately estimated by interpolation methods. This work investigated the relationship between Air Temperature measured at meteorological stations and spatially contiguous measurements derived from Remote Sensing techniques, such as Land Surface Temperature (LST) maps, emissivity maps and shortwave radiation maps with the aim of creating a continuous map of AirT. For LST and emissivity, MSG-SEVIRI LST product from Land Surface Analysis Satellite Applications Facility (LSA-SAF) has been used. For shortwave radiation maps, an Artificial Neural Networks ensemble model has been developed and previously tested to create continuous maps from Global Horizontal Irradiance (GHI) point measurements, utilizing six thermal channels of MSG-SEVIRI. The testing sites corresponded to three meteorological stations located in the United Arab Emirates (UAE), where in situ measurements of Air Temperature were available. From the starting parameters, energy fluxes and net radiation have been calculated, in order to have information on the incoming and outgoing long-wave radiation and the incoming short-wave radiation. The preliminary analysis (day and Night measurements, cloud free) showed a strong negative correlation (0.92) between Outgoing long-wave radiation - GHI and LST- AirT, with a RMSE of 1.84 K in the AirT estimation from the initial parameters. Regression coefficients have been determined and tested on all the ground stations. The analysis also demonstrated the predominant impact of the incoming short-wave radiation in the AirT hourly variation, while the incoming

  1. Comparison of Near-Surface Air Temperatures and MODIS Ice-Surface Temperatures at Summit, Greenland (2008-2013)

    Science.gov (United States)

    Shuman, Christopher A.; Hall, Dorothy K.; DiGirolamo, Nicolo E.; Mefford, Thomas K.; Schnaubelt, Michael J.

    2014-01-01

    We have investigated the stability of the MODerate resolution Imaging Spectroradiometer (MODIS) infrared-derived ice surface temperature (IST) data from Terra for use as a climate quality data record. The availability of climate quality air temperature data (TA) from a NOAA Global Monitoring Division observatory at Greenlands Summit station has enabled this high temporal resolution study of MODIS ISTs. During a 5 year period (July 2008 to August 2013), more than 2500 IST values were compared with 3-minute average TA values derived from the 1-minute data from NOAAs primary 2 m air temperature sensor. These data enabled an expected small offset between air and surface temperatures at this the ice sheet location to be investigated over multiple annual cycles.

  2. Evaluation of VIIRS Land Surface Temperature Using CREST-SAFE Air, Snow Surface, and Soil Temperature Data

    Directory of Open Access Journals (Sweden)

    Carlos L. Pérez Díaz

    2015-12-01

    Full Text Available In this study, the Visible Infrared Imager Radiometer Suite (VIIRS Land Surface Temperature (LST Environmental Data Record (EDR was evaluated against snow surface (T-skin and near-surface air temperature (T-air ground observations recorded at the Cooperative Remote Sensing Science and Technology Center—Snow Analysis and Field Experiment (CREST-SAFE, located in Caribou, ME, USA during the winters of 2013 and 2014. The satellite LST corroboration of snow-covered areas is imperative because high-latitude regions are often physically inaccessible and there is a need to complement the data from the existing meteorological station networks. T-skin is not a standard meteorological parameter commonly observed at synoptic stations. Common practice is to measure surface infrared emission from the land surface at research stations across the world that allow for estimating ground-observed LST. Accurate T-skin observations are critical for estimating latent and sensible heat fluxes over snow-covered areas because the incoming and outgoing radiation fluxes from the snow mass and T-air make the snow surface temperature different from the average snowpack temperature. Precise characterization of the LST using satellite observations is an important issue because several climate and hydrological models use T-skin as input. Results indicate that T-air correlates better than T-skin with VIIRS LST data and that the accuracy of nighttime LST retrievals is considerably better than that of daytime. Based on these results, empirical relationships to estimate T-air and T-skin for clear-sky conditions from remotely-sensed (RS LST were derived. Additionally, an empirical formula to correct cloud-contaminated RS LST was developed.

  3. Daily Cycle of Air Temperature and Surface Temperature in Stone Forest

    Science.gov (United States)

    Wang, K.; Li, Y.; Wang, X.; Yuan, M.

    2013-12-01

    Urbanization is one of the most profound human activities that impact on climate change. In cities, where are highly artificial areas, the conflict between human activity and natural climate is particularly prominent. Urban areas always have the larger area of impervious land, the higher consumption of greenhouse gases, more emissions of anthropogenic heat and air pollution, all contribute to the urban warming phenomena. Understanding the mechanisms causing a variety of phenomena involved in the urban warming is critical to distinguish the anthropogenic effect and natural variation in the climate change. However, the exact dynamics of urban warming were poorly understood, and effective control strategies are not available. Here we present a study of the daily cycle of air temperature and surface temperature in Stone Forest. The specific heat of the stones in the Stone Forest and concrete of the man-made structures within the cities are approximate. Besides, the height of the Stone Forest and the height of buildings within the city are also similar. As a scenic area, the Stone Forest is being preserved and only opened for sightseeing. There is no anthropogenic heat, as well air pollution within the Stone Forest. The thermal environment in Stone Forest can be considered to be a simulation of thermal environment in the city, which can reveal the effect of man-made structures on urban thermal environment. We conducted the field studies and numerical analysis in the Stone Forest for 4 typical urban morphology and environment scenarios, including high-rise compact cities, low-rise sparse cities, garden cities and isolated single stone. Air temperature and relative humidity were measured every half an hour in 15 different locations, which within different spatial distribution of stones and can represent the four urban scenarios respectively. At the same time, an infrared camera was used to take thermal images and get the hourly surface temperatures of stones and

  4. Air Surface Temperature Correlation with Greenhouse Gases by Using Airs Data Over Peninsular Malaysia

    Science.gov (United States)

    Rajab, Jasim Mohammed; MatJafri, M. Z.; Lim, H. S.

    2014-08-01

    The main objective of this study is to develop algorithms for calculating the air surface temperature (AST). This study also aims to analyze and investigate the effects of greenhouse gases (GHGs) on the AST value in Peninsular Malaysia. Multiple linear regression is used to achieve the objectives of the study. Peninsular Malaysia has been selected as the research area because it is among the regions of tropical Southeast Asia with the greatest humidity, pockets of heavy pollution, rapid economic growth, and industrialization. The predicted AST was highly correlated ( R = 0.783) with GHGs for the 6-year data (2003-2008). Comparisons of five stations in 2009 showed close agreement between the predicted AST and the observed AST from AIRS, especially in the wet season (within 1.3 K). The in situ data ranged from 1 to 2 K. Validation results showed that AST ( R = 0.776-0.878) has values nearly the same as the observed AST from AIRS. We found that O3 during the wet season was indicated by a strongly positive beta coefficient (0.264-0.992) with AST. The CO2 yields a reasonable relationship with temperature with low to moderate beta coefficient (-0.065 to 0.238). The O3, CO2, and environmental variables experienced different seasonal fluctuations that depend on weather conditions and topography. The concentration of gases and pollution were the highest over industrial zones and overcrowded cities, and the dry season was more polluted compared with the wet season. These results indicate the advantage of using the satellite AIRS data and a correlation analysis to investigate the effect of atmospheric GHGs on AST over Peninsular Malaysia. An algorithm that is capable of retrieving Peninsular Malaysian AST in all weather conditions with total uncertainties ranging from 1 to 2 K was developed.

  5. Estimating Temperature Fields from MODIS Land Surface Temperature and Air Temperature Observations in a Sub-Arctic Alpine Environment

    Directory of Open Access Journals (Sweden)

    Scott N. Williamson

    2014-01-01

    Full Text Available Spatially continuous satellite infrared temperature measurements are essential for understanding the consequences and drivers of change, at local and regional scales, especially in northern and alpine environments dominated by a complex cryosphere where in situ observations are scarce. We describe two methods for producing daily temperature fields using MODIS “clear-sky” day-time Land Surface Temperatures (LST. The Interpolated Curve Mean Daily Surface Temperature (ICM method, interpolates single daytime Terra LST values to daily means using the coincident diurnal air temperature curves. The second method calculates daily mean LST from daily maximum and minimum LST (MMM values from MODIS Aqua and Terra. These ICM and MMM models were compared to daily mean air temperatures recorded between April and October at seven locations in southwest Yukon, Canada, covering characteristic alpine land cover types (tundra, barren, glacier at elevations between 1,408 m and 2,319 m. Both methods for producing mean daily surface temperatures have advantages and disadvantages. ICM signals are strongly correlated with air temperature (R2 = 0.72 to 0.86, but have relatively large variability (RMSE = 4.09 to 4.90 K, while MMM values had a stronger correlation to air temperature (R2 = 0.90 and smaller variability (RMSE = 2.67 K. Finally, when comparing 8-day LST averages, aggregated from the MMM method, to air temperature, we found a high correlation (R2 = 0.84 with less variability (RMSE = 1.54 K. Where the trend was less steep and the y-intercept increased by 1.6 °C compared to the daily correlations. This effect is likely a consequence of LST temperature averages being differentially affected by cloud cover over warm and cold surfaces. We conclude that satellite infrared skin temperature (e.g., MODIS LST, which is often aggregated into multi-day composites to mitigate data reductions caused by cloud cover, changes in its relationship to air temperature

  6. Global Distribution and Variability of Surface Skin and Surface Air Temperatures as Depicted in the AIRS Version-6 Data Set

    Science.gov (United States)

    Susskind, Joel; Lee, Jae N.; Iredell, Lena

    2014-01-01

    In this presentation, we will briefly describe the significant improvements made in the AIRS Version-6 retrieval algorithm, especially as to how they affect retrieved surface skin and surface air temperatures. The global distribution of seasonal 1:30 AM and 1:30 PM local time 12 year climatologies of Ts,a will be presented for the first time. We will also present the spatial distribution of short term 12 year anomaly trends of Ts,a at 1:30 AM and 1:30 PM, as well as the spatial distribution of temporal correlations of Ts,a with the El Nino Index. It will be shown that there are significant differences between the behavior of 1:30 AM and 1:30 PM Ts,a anomalies in some arid land areas.

  7. Validation of AIRS V6 Surface Temperature over Greenland with GCN and NOAA Stations

    Science.gov (United States)

    Lee, Jae N.; Hearty, Thomas; Cullather, Richard; Nowicki, Sophie; Susskind, Joel

    2016-01-01

    This work compares the temporal and spatial characteristics of the AIRSAMSU (Atmospheric Infrared Sounder Advanced Microwave Sounding Unit A) Version 6 and MODIS (Moderate resolution Imaging Spectroradiometer) Collection 5 derived surface temperatures over Greenland. To estimate uncertainties in space-based surface temperature measurements, we re-projected the MODIS Ice Surface Temperature (IST) to 0.5 by 0.5 degree spatial resolution. We also re-gridded AIRS Skin Temperature (Ts) into the same grid but classified with different cloud conditions and surface types. These co-located data sets make intercomparison between the two instruments relatively straightforward. Using this approach, the spatial comparison between the monthly mean AIRS Ts and MODIS IST is in good agreement with RMS 2K for May 2012. This approach also allows the detection of any long-term calibration drift and the careful examination of calibration consistency in the MODIS and AIRS temperature data record. The temporal correlations between temperature data are also compared with those from in-situ measurements from GC-Net (GCN) and NOAA stations. The coherent time series of surface temperature evident in the correlation between AIRS Ts and GCN temperatures suggest that at monthly time scales both observations capture the same climate signal over Greenland. It is also suggested that AIRS surface air temperature (Ta) can be used to estimate the boundary layer inversion.

  8. Robust comparison of climate models with observations using blended land air and ocean sea surface temperatures

    OpenAIRE

    Cowtan, Kevin; Hausfather, Zeke; Hawkins, Ed; Jacobs, Peter; Mann, Michael E.; Miller, Sonya K.; Byron A. Steinman; Stolpe, Martin B.; Way, Robert G.

    2015-01-01

    The level of agreement between climate model simulations and observed surface temperature change is a topic of scientific and policy concern. While the Earth system continues to accumulate energy due to anthropogenic and other radiative forcings, estimates of recent surface temperature evolution fall at the lower end of climate model projections. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observation...

  9. Near–surface air temperature and snow skin temperature comparison from CREST-SAFE station data with MODIS land surface temperature data

    Directory of Open Access Journals (Sweden)

    C. L. Pérez Díaz

    2015-08-01

    Full Text Available Land Surface Temperature (LST is a key variable (commonly studied to understand the hydrological cycle that helps drive the energy balance and water exchange between the Earth's surface and its atmosphere. One observable constituent of much importance in the land surface water balance model is snow. Snow cover plays a critical role in the regional to global scale hydrological cycle because rain-on-snow with warm air temperatures accelerates rapid snow-melt, which is responsible for the majority of the spring floods. Accurate information on near-surface air temperature (T-air and snow skin temperature (T-skin helps us comprehend the energy and water balances in the Earth's hydrological cycle. T-skin is critical in estimating latent and sensible heat fluxes over snow covered areas because incoming and outgoing radiation fluxes from the snow mass and the air temperature above make it different from the average snowpack temperature. This study investigates the correlation between MODerate resolution Imaging Spectroradiometer (MODIS LST data and observed T-air and T-skin data from NOAA-CREST-Snow Analysis and Field Experiment (CREST-SAFE for the winters of 2013 and 2014. LST satellite validation is imperative because high-latitude regions are significantly affected by climate warming and there is a need to aid existing meteorological station networks with the spatially continuous measurements provided by satellites. Results indicate that near-surface air temperature correlates better than snow skin temperature with MODIS LST data. Additional findings show that there is a negative trend demonstrating that the air minus snow skin temperature difference is inversely proportional to cloud cover. To a lesser extent, it will be examined whether the surface properties at the site are representative for the LST properties within the instrument field of view.

  10. Near-surface air temperature and snow skin temperature comparison from CREST-SAFE station data with MODIS land surface temperature data

    Science.gov (United States)

    Pérez Díaz, C. L.; Lakhankar, T.; Romanov, P.; Muñoz, J.; Khanbilvardi, R.; Yu, Y.

    2015-08-01

    Land Surface Temperature (LST) is a key variable (commonly studied to understand the hydrological cycle) that helps drive the energy balance and water exchange between the Earth's surface and its atmosphere. One observable constituent of much importance in the land surface water balance model is snow. Snow cover plays a critical role in the regional to global scale hydrological cycle because rain-on-snow with warm air temperatures accelerates rapid snow-melt, which is responsible for the majority of the spring floods. Accurate information on near-surface air temperature (T-air) and snow skin temperature (T-skin) helps us comprehend the energy and water balances in the Earth's hydrological cycle. T-skin is critical in estimating latent and sensible heat fluxes over snow covered areas because incoming and outgoing radiation fluxes from the snow mass and the air temperature above make it different from the average snowpack temperature. This study investigates the correlation between MODerate resolution Imaging Spectroradiometer (MODIS) LST data and observed T-air and T-skin data from NOAA-CREST-Snow Analysis and Field Experiment (CREST-SAFE) for the winters of 2013 and 2014. LST satellite validation is imperative because high-latitude regions are significantly affected by climate warming and there is a need to aid existing meteorological station networks with the spatially continuous measurements provided by satellites. Results indicate that near-surface air temperature correlates better than snow skin temperature with MODIS LST data. Additional findings show that there is a negative trend demonstrating that the air minus snow skin temperature difference is inversely proportional to cloud cover. To a lesser extent, it will be examined whether the surface properties at the site are representative for the LST properties within the instrument field of view.

  11. Near–surface air temperature and snow skin temperature comparison from CREST-SAFE station data with MODIS land surface temperature data

    OpenAIRE

    C. L. Pérez Díaz; T. Lakhankar; P. Romanov; Muñoz, J; R. Khanbilvardi; Yu, Y.

    2015-01-01

    Land Surface Temperature (LST) is a key variable (commonly studied to understand the hydrological cycle) that helps drive the energy balance and water exchange between the Earth's surface and its atmosphere. One observable constituent of much importance in the land surface water balance model is snow. Snow cover plays a critical role in the regional to global scale hydrological cycle because rain-on-snow with warm air temperatures accelera...

  12. Sensitivity of surface air temperature change to land use/cover types in China

    Institute of Scientific and Technical Information of China (English)

    YANG XuChao; ZHANG YiLi; LIU LinShan; ZHANG Wei; DING MingJun; WANG ZhaoFeng

    2009-01-01

    Using CRU high resolution grid observational temperature and ERA40 reanalysie surface air temperature data during 1960--1999, we investigated the sensitivity of surface air temperature change to land use/cover types in China by subtracting the reanalysis from the observed surface air temperature (observation minus reanalysis, OMR). The results show that there is a stable and systemic impact of land use/cover types on surface air temperature. The surface warming of each land use/cover type reacted differently to global warming. The OMR trends of unused land (≥0.17℃/decade), mainly comprised by sandy land, Gobi and bare rock gravel land, are obviously larger than those of the other land use/cover types. The OMR over grassland, farmland and construction land shows a moderate decadal a significant warming trend (0.06"C/decade). The overall assessment indicates that the surface warming is larger for areas that are barren and anthropogenically developed. The better the vegetation cover, the smaller the OMR warming trend. Responses of surface air temperature to land use/cover types with similar physical and chemical properties and biological processes have no significant difference. The surface air temperature would not react significantly until the intensity of land cover changes reach a certain degree. Within the same land use/cover type, areas in eastern China with intensive human activities exhibit larger warming trend. The results provide observational evidence for modeling research on the impact of land use/cover change on regional climate. Thus, projecting further surface climate of China in regional scale should not only take greenhouse gas increase into account, but also consider the impact of land use/cover types and land cover change.

  13. Air moisture control on ocean surface temperature, hidden key to the warm bias enigma

    Science.gov (United States)

    Hourdin, Frédéric; Gǎinusǎ-Bogdan, Alina; Braconnot, Pascale; Dufresne, Jean-Louis; Traore, Aboul-Khadre; Rio, Catherine

    2015-12-01

    The systematic overestimation by climate models of the surface temperature over the eastern tropical oceans is generally attributed to an insufficient oceanic cooling or to an underestimation of stratocumulus clouds. We show that surface evaporation contributes as much as clouds to the dispersion of the warm bias intensity in a multimodel simulations ensemble. The models with the largest warm biases are those with the highest surface heating by radiation and lowest evaporative cooling in atmospheric simulations with prescribed sea surface temperatures. Surface evaporation also controls the amplitude of the surface temperature response to this overestimated heating, when the atmosphere is coupled to an ocean. Evaporation increases with temperature both because of increasing saturation humidity and of an unexpected drying of the near-surface air. Both the origin of the bias and this temperature adjustment point to the key role of near-surface relative humidity and its control by the atmospheric model.

  14. Surface Air Temperature Simulations over China with CMIP5 and CMIP3

    Institute of Scientific and Technical Information of China (English)

    GUO; Yan; DONG; Wen-Jie; REN; Fu-Min; ZHAO; Zong-Ci; HUANG; Jian-Bin

    2013-01-01

    Historical simulations of annual mean surface air temperature over China with 25 CMIP5 models were assessed.The observational data from CRUT3v and CN05 were used and further compared with historical simulations of CMIP3.The results show that CMIP5 models were able to simulate the observed warming over China from 1906 to 2005(0.84 C per 100 years)with a warming rate of 0.77 C per 100 years based on the multi-model ensemble(MME).The simulations of surface air temperature in the late 20th century were much better than those in the early 20th century,when only two models could reproduce the extreme warming in the 1940s.The simulations for the spatial distribution of the 20-yearmean(1986–2005)surface air temperature over China fit relatively well with the observations.However,underestimations in surface air temperature climatology were still found almost all over China,and the largest cold bias and simulation uncertainty were found in western China.On sub-regional scale,northern China experienced stronger warming than southern China during 1961–1999,for which the CMIP5 MME provided better simulations.With CMIP5 the diference of warming trends in northern and southern China was underestimated.In general,the CMIP5 simulations are obviously improved in comparison with the CMIP3 simulations in terms of the variation in regional mean surface air temperature,the spatial distribution of surface air temperature climatology and the linear trends in surface air temperature all over China.

  15. A simple lumped model to convert air temperature into surface water temperature in lakes

    Directory of Open Access Journals (Sweden)

    S. Piccolroaz

    2013-03-01

    Full Text Available Water temperature in lakes is governed by a complex heat budget, where the single fluxes are hardly assessable over long time periods in the absence of high accuracy data. In order to address this issue, we developed Air2Water, a simple physically-based model to relate the temperature of the lake superficial layer (epilimnion to air temperature only. The model accounts for the overall heat exchanges with the atmosphere and the deeper layer of the lake (hypolimnion by means of simplified relationships, which contain a few parameters (from four to eight in the different proposed formulations to be calibrated with the combined use of air and water temperature measurements. In particular, the calibration of the parameters in a given case study allows one to estimate, in a synthetic way, the influence of the main processes controlling the lake thermal dynamics, and to recognize the atmospheric temperature as the main factor driving the evolution of the system. In fact, the air temperature variation implicitly contains proper information about the variation of other major processes, and hence in our approach is considered as the only input variable of the model. Furthermore, the model can be easily used to predict the response of a lake to climate change, since projected air temperatures are usually available by large-scale global circulation models. In this paper, the model is applied to Lake Superior (USA – Canada considering a 27-yr record of measurements, among which 18 yr used for calibration and the remaining 9 yr for model validation. The results show a remarkable agreement with measurements, over the entire data period. The use of air temperature reconstructed by satellite imagery is also discussed.

  16. Uncertainties of satellite-derived surface skin temperatures in the polar oceans: MODIS, AIRS/AMSU, and AIRS only

    Science.gov (United States)

    Kang, H.-J.; Yoo, J.-M.; Jeong, M.-J.; Won, Y.-I.

    2015-10-01

    Uncertainties in the satellite-derived surface skin temperature (SST) data in the polar oceans during two periods (16-24 April and 15-23 September) 2003-2014 were investigated and the three data sets were intercompared as follows: MODerate Resolution Imaging Spectroradiometer Ice Surface Temperature (MODIS IST), the SST of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A (AIRS/AMSU), and AIRS only. The AIRS only algorithm was developed in preparation for the degradation of the AMSU-A. MODIS IST was systematically warmer up to 1.65 K at the sea ice boundary and colder down to -2.04 K in the polar sea ice regions of both the Arctic and Antarctic than that of the AIRS/AMSU. This difference in the results could have been caused by the surface classification method. The spatial correlation coefficient of the AIRS only to the AIRS/AMSU (0.992-0.999) method was greater than that of the MODIS IST to the AIRS/AMSU (0.968-0.994). The SST of the AIRS only compared to that of the AIRS/AMSU had a bias of 0.168 K with a RMSE of 0.590 K over the Northern Hemisphere high latitudes and a bias of -0.109 K with a RMSE of 0.852 K over the Southern Hemisphere high latitudes. There was a systematic disagreement between the AIRS retrievals at the boundary of the sea ice, because the AIRS only algorithm utilized a less accurate GCM forecast over the seasonally varying frozen oceans than the microwave data. The three data sets (MODIS, AIRS/AMSU and AIRS only) showed significant warming rates (2.3 ± 1.7 ~ 2.8 ± 1.9 K decade-1) in the northern high regions (70-80° N) as expected from the ice-albedo feedback. The systematic temperature disagreement associated with surface type classification had an impact on the resulting temperature trends.

  17. Uncertainties of satellite-derived surface skin temperatures in the polar oceans: MODIS, AIRS/AMSU, and AIRS only

    Directory of Open Access Journals (Sweden)

    H.-J. Kang

    2015-05-01

    Full Text Available Uncertainties in the satellite-derived Surface Skin Temperature (SST data in the polar oceans during two periods (16–24 April and 15–23 September of 2003–2014 were investigated and the three datasets were intercompared as follows: MODerate Resolution Imaging Spectroradiometer Ice Surface Temperature (MODIS IST, the SST of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A (AIRS/AMSU, and AIRS only. AIRS only algorithm was developed in preparation for the degradation of the AMSU-A. MODIS IST was systematically up to 1.65 K warmer at the sea ice boundary and up to 2.04 K colder in the polar sea ice regions of both the Arctic and Antarctic than that of the AIRS/AMSU. This difference in the results could have been caused by the surface classification method. The spatial correlation coefficient of the AIRS only to the AIRS/AMSU (0.992–0.999 method was greater than that of the MODIS IST to the AIRS/AMSU (0.968–0.994. The SST of the AIRS only compared to that of the AIRS/AMSU had a bias of 0.168 K with a RMSE of 0.590 K over the Northern Hemisphere high latitudes and a bias of −0.109 K with a RMSE of 0.852 K over the Southern Hemisphere high latitudes. There was a systematic disagreement between the AIRS retrievals at the boundary of the sea ice, because the AIRS only algorithm utilized a~less accurate GCM forecast over the seasonally-varying frozen oceans than the microwave data. The three datasets (MODIS, AIRS/AMSU and AIRS only showed significant warming rates (2.3 ± 1.7 ~2.8 ± 1.9 K decade−1 in the northern high latitude regions (70–80° N as expected from the ice-albedo feedback. The systematic temperature disagreement associated with surface type classification had an impact on the resulting temperature trends.

  18. A simplified physically-based model to calculate surface water temperature of lakes from air temperature in climate change scenarios

    Science.gov (United States)

    Piccolroaz, S.; Toffolon, M.

    2012-12-01

    Modifications of water temperature are crucial for the ecology of lakes, but long-term analyses are not usually able to provide reliable estimations. This is particularly true for climate change studies based on Global Circulation Models, whose mesh size is normally too coarse for explicitly including even some of the biggest lakes on Earth. On the other hand, modeled predictions of air temperature changes are more reliable, and long-term, high-resolution air temperature observational datasets are more available than water temperature measurements. For these reasons, air temperature series are often used to obtain some information about the surface temperature of water bodies. In order to do that, it is common to exploit regression models, but they are questionable especially when it is necessary to extrapolate current trends beyond maximum (or minimum) measured temperatures. Moreover, water temperature is influenced by a variety of processes of heat exchange across the lake surface and by the thermal inertia of the water mass, which also causes an annual hysteresis cycle between air and water temperatures that is hard to consider in regressions. In this work we propose a simplified, physically-based model for the estimation of the epilimnetic temperature in lakes. Starting from the zero-dimensional heat budget, we derive a simplified first-order differential equation for water temperature, primarily forced by a seasonally varying external term (mainly related to solar radiation) and an exchange term explicitly depending on the difference between air and water temperatures. Assuming annual sinusoidal cycles of the main heat flux components at the atmosphere-lake interface, eight parameters (some of them can be disregarded, though) are identified, which can be calibrated if two temporal series of air and water temperature are available. We note that such a calibration is supported by the physical interpretation of the parameters, which provide good initial

  19. Prediction of Monthly Mean Surface Air Temperature in a Region of China

    Institute of Scientific and Technical Information of China (English)

    Jeong-Hyeong LEE; Keon-Tae SOHN

    2007-01-01

    In conventional time series analysis, a process is often modeled as three additive components: linear trend, seasonal effect, and random noise. In this paper, we perform an analysis of surface air temperature in a region of China using a decomposition method in time series analysis. Applications to the National Centers for Environmental Prediction/the National Center for Atmospheric Research (NCEP/NCAR) Collaborative Reanalysis data in this region of China are discussed. The main finding was that the surface air temperature trend estimated for January 1948 to February 2006 was not statistically significant at 0.5904℃ (100 yr)-1.Forecasting aspects are also considered.

  20. Global circuit response to seasonal variations in global surface air temperature

    Science.gov (United States)

    Williams, Earle R.

    1994-01-01

    Comparisons are made between the seasonal behavior of the global electrical circuit and the surface air temperature for the Tropics and for the globe. Positive correlations between global circuit parameters and temperature are identified on both semiannual and annual timescales. Lightning is the global circuit quantity found most responsive to temperature, with a sensitivity of the order of 10% per 1 C. These findings lend further validity to the use of global circuit measurements as a diagnostic for global change.

  1. Statistical relationships between the surface air temperature anomalies and the solar and geomagnetic activity indices

    OpenAIRE

    Valev, Dimitar

    2010-01-01

    Statistical analysis of the data series from 1856 to 2000 for the annual global and hemispheric surface air temperature anomalies is completed. Statistically significant correlations are found between global and hemispheric temperature anomalies and solar and geomagnetic indices. The temperature anomalies in the Northern and Southern hemispheres show similar statistical relations with the solar and geomagnetic indices. The cross-correlation analysis shows no statistically significant global t...

  2. Near surface spatially averaged air temperature and wind speed determined by acoustic travel time tomography

    Directory of Open Access Journals (Sweden)

    Armin Raabe

    2001-03-01

    Full Text Available Acoustic travel time tomography is presented as a possibility for remote monitoring of near surface airtemperature and wind fields. This technique provides line-averaged effective sound speeds changing with temporally and spatially variable air temperature and wind vector. The effective sound speed is derived from the travel times of sound signals which propagate at defined paths between different acoustic sources and receivers. Starting with the travel time data a tomographic algorithm (Simultaneous Iterative Reconstruction Technique, SIRT is used to calculate area-averaged air temperature and wind speed. The accuracy of the experimental method and the tomographic inversion algorithm is exemplarily demonstrated for one day without remarkable differences in the horizontal temperature field, determined by independent in situ measurements at different points within the measuring field. The differences between the conventionally determined air temperature (point measurement and the air temperature determined by tomography (area-averaged measurement representative for the area of the measuring field 200m x 260m were below 0.5 K for an average of 10 minutes. The differences obtained between the wind speed measured at a meteorological mast and calculated from acoustic measurements are not higher than 0.5 ms-1 for the same averaging time. The tomographically determined area-averaged distribution of air temperature (resolution 50 m x 50 m can be used to estimate the horizontal gradient of air temperature as a pre-condition to detect horizontal turbulent fluxes of sensible heat.

  3. A simple lumped model to convert air temperature into surface water temperature in lakes

    Directory of Open Access Journals (Sweden)

    S. Piccolroaz

    2013-08-01

    Full Text Available Water temperature in lakes is governed by a complex heat budget, where the estimation of the single fluxes requires the use of several hydro-meteorological variables that are not generally available. In order to address this issue, we developed Air2Water, a simple physically based model to relate the temperature of the lake superficial layer (epilimnion to air temperature only. The model has the form of an ordinary differential equation that accounts for the overall heat exchanges with the atmosphere and the deeper layer of the lake (hypolimnion by means of simplified relationships, which contain a few parameters (from four to eight in the different proposed formulations to be calibrated with the combined use of air and water temperature measurements. The calibration of the parameters in a given case study allows for one to estimate, in a synthetic way, the influence of the main processes controlling the lake thermal dynamics, and to recognize the atmospheric temperature as the main factor driving the evolution of the system. In fact, under certain hypotheses the air temperature variation implicitly contains proper information about the other major processes involved, and hence in our approach is considered as the only input variable of the model. In particular, the model is suitable to be applied over long timescales (from monthly to interannual, and can be easily used to predict the response of a lake to climate change, since projected air temperatures are usually available by large-scale global circulation models. In this paper, the model is applied to Lake Superior (USA–Canada considering a 27 yr record of measurements, among which 18 yr are used for calibration and the remaining 9 yr for model validation. The calibration of the model is obtained by using the generalized likelihood uncertainty estimation (GLUE methodology, which also allows for a sensitivity analysis of the parameters. The results show remarkable agreement with

  4. Air and Ground Surface Temperature Relations in a Mountainous Basin, Wolf Creek, Yukon Territory

    Science.gov (United States)

    Roadhouse, Emily A.

    The links between climate and permafrost are well known, but the precise nature of the relationship between air and ground temperatures remains poorly understood, particularly in complex mountain environments. Although previous studies indicate that elevation and potential incoming solar radiation (PISR) are the two leading factors contributing to the existence of permafrost at a given location, additional factors may also contribute significantly to the existence of mountain permafrost, including vegetation cover, snow accumulation and the degree to which individual mountain landscapes are prone to air temperature inversions. Current mountain permafrost models consider only elevation and aspect, and have not been able to deal with inversion effects in a systematic fashion. This thesis explores the relationship between air and ground surface temperatures and the presence of surface-based inversions at 27 sites within the Wolf Creek basin and surrounding area between 2001 and 2006, as a first step in developing an improved permafrost distribution TTOP model. The TTOP model describes the relationship between the mean annual air temperature and the temperature at the top of permafrost in terms of the surface and thermal offsets (Smith and Riseborough, 2002). Key components of this model are n-factors which relate air and ground climate by establishing the ratio between air and surface freezing (winter) and thawing (summer) degree-days, thus summarizing the surface energy balance on a seasonal basis. Here we examine (1) surface offsets and (2) freezing and thawing n-factor variability at a number of sites through altitudinal treeline in the southern Yukon. Thawing n-factors (nt) measured at individual sites remained relatively constant from one year to the next and may be related to land cover. During the winter, the insulating effect of a thick snow cover results in higher surface temperatures, while thin snow cover results in low surface temperatures more closely

  5. Nest temperatures in a loggerhead nesting beach in Turkey is more determined by sea surface than air temperature.

    Science.gov (United States)

    Girondot, Marc; Kaska, Yakup

    2015-01-01

    While climate change is now fully recognised as a reality, its impact on biodiversity is still not completely understood. To predict its impact, proxies coherent with the studied ecosystem or species are thus required. Marine turtles are threatened worldwide (though some populations are recovering) as they are particularly sensitive to temperature throughout their entire life cycle. This is especially true at the embryo stage when temperature affects both growth rates and sex determination. Nest temperature is thus of prime importance to understand the persistence of populations in the context of climate change. We analysed the nest temperature of 21 loggerheads (Caretta caretta) originating from Dalyan Beach in Turkey using day-lagged generalised mixed models with autocorrelation. Surprisingly, the selected model for nest temperature includes an effect for sea surface temperature 4-times higher than for air temperature. We also detected a very significant effect of metabolic heating during development compatible with what is already known about marine turtle nests. Our new methodology allows the prediction of marine turtle nest temperatures with good precision based on a combination of air temperature measured at beach level and sea surface temperature in front of the beach. These data are available in public databases for most of the beaches worldwide. PMID:25526649

  6. Detecting and Adjusting Temporal Inhomogeneity in Chinese Mean Surface Air Temperature Data

    Institute of Scientific and Technical Information of China (English)

    LI Qingxiang(李庆祥); LIU Xiaoning(刘小宁); ZHANG Hongzheng(张洪政); Thomas C. PETERSON; David R. EASTERLING

    2004-01-01

    Adopting the Easterling-Peterson (EP) techniques and considering the reality of Chinese meteorological observations, this paper designed several tests and tested for inhomogeneities in all Chinese historical surface air temperature series from 1951 to 2001. The result shows that the time series have been widely impacted by inhomogeneities resulting from the relocation of stations and changes in local environment such as urbanization or some other factors. Among these factors, station relocations caused the largest magnitude of abrupt changes in the time series, and other factors also resulted in inhomogeneities to some extent. According to the amplitude of change of the difference series and the monthly distribution features of surface air temperatures, discontinuities identified by applying both the E-P technique and supported by China's station history records, or by comparison with other approaches, have been adjusted. Based on the above processing, the most significant temporal inhomogeneities were eliminated, and China's most homogeneous surface air temperature series has thus been created. Results show that the inhomogeneity testing captured well the most important change of the stations, and the adjusted dataset is more reliable than ever. This suggests that the adjusted temperature dataset has great value of decreasing the uncertaities in the study of observed climate change in China.

  7. Determining Land Surface Temperature Relations with Land Use-Land Cover and Air Pollution

    Science.gov (United States)

    Kahya, Ceyhan; Bektas Balcik, Filiz; Burak Oztaner, Yasar; Guney, Burcu

    2016-04-01

    Rapid population growth in conjunction with unplanned urbanization, expansion, and encroachment into the limited agricultural fields and green areas have negative impacts on vegetated areas. Land Surface Temperature (LST), Urban Heat Islands (UHI) and air pollution are the most important environmental problems that the extensive part of the world suffers from. The main objective of this research is to investigate the relationship between LST, air pollution and Land Use-Land Cover (LULC) in Istanbul, using Landsat 8 OLI satellite image. Mono-window algorithm is used to compute LST from Landsat 8 TIR data. In order to determine the air pollution, in-situ measurements of particulate matter (PM10) of the same day as the Landsat 8 OLI satellite image are obtained. The results of this data are interpolated using the Inverse Distance Weighted (IDW) method and LULC categories of Istanbul were determined by using remote sensing indices. Error matrix was created for accuracy assessment. The relationship between LST, air pollution and LULC categories are determined by using regression analysis method. Keywords: Land Surface Temperature (LST), air pollution, Land Use-Land Cover (LULC), Istanbul

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

    Science.gov (United States)

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

    2016-04-01

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

  9. Monthly Changes in the Influence of the Arctic Oscillation on Surface Air Temperature over China

    Institute of Scientific and Technical Information of China (English)

    HUANG Jiayou; TAN Benkui; SUO Lingling; HU Yongyun

    2007-01-01

    Partial Least Squares Regression (PLSR) is used to study monthly changes in the influence of the Arctic Oscillation (AO) on spring, summer and autumn air temperature over China with the January 500 hPa geopotential height data from 1951 to 2004 and monthly temperature data from January to November at 160 stations in China. Several AO indices have been defined with the 500-hPa geopotential data and the index defined as the first principal component of the normalized geopotential data is best to be used to study the influence of the AO on SAT (surface air temperature) in China. There are three modes through which the AO in winter influences SAT in China. The influence of the AO on SAT in China changes monthly and is stronger in spring and summer than in autumn. The main influenced regions are Northeast China and the Changjiang River drainage area.

  10. Topoclimatic modeling of summer surface air temperature in the Canadian Arctic Archipelago

    Science.gov (United States)

    Atkinson, David E.

    2000-06-01

    In the Canadian High Arctic general patterns of temperature are poorly resolved at the meso-scale. This project addressed this issue in three stages. In the first stage a data set of non-standard weather observations was assembled and quality controlled The data set possessed approximately 58000 observations, including dry-bulb temperature, wind, visibility and cloud cover, from the spring and summer seasons of the years 1974-1993. Up to 10% of the data were unusable due to erroneous station information. The second part of the project consisted of a principal components analysis (PCA) of daily temperature data in the Canadian Arctic Archipelago (CAA). The PCA (1)demonstrated how the timing and extent of synoptic events could be tracked, (2)identified the major regional controls of temperature in the CAA, and (3)showed that the non-standard data exhibited general coherency with regional patterns yet were able to reveal zones of coherency at the meso-scale in temperature patterns. In the third stage of the project a model to estimate surface air temperature at the meso-scale was constructed, It was based on a 1 km resolution digital elevation model of the CAA. The effects on temperature due to site elevation and coastal proximity were selected for parameterization. The change in temperature with elevation was implemented in the model using derived environmental lapse rates. Advection effects were handled using resultant winds combined with air temperature above the ocean. Lapse rates and resultant wind estimates were obtained from upper air ascents. Model results for 14-day runs were compared to observed data. Residuals (n = 385) possessed a mean absolute error of 1.5°C. The model was sensitive to steep surface inversions and to low- level warming. Sensitivity analyses were performed on the model to determine response to alterations in lapse rate calculation, sea surface temperature, and wind field generation. The model was most sensitive to lapse rate calculation

  11. Borehole temperatures, climate change and the pre-observational surface air temperature mean: allowance for hydraulic conditions

    Czech Academy of Sciences Publication Activity Database

    Bodri, L.; Čermák, Vladimír

    2005-01-01

    Roč. 45, č. 4 (2005), s. 265-276. ISSN 0921-8181 R&D Projects: GA AV ČR IAA3012005; GA ČR GA205/03/0998; GA AV ČR KSK3046108 Institutional research plan: CEZ:AV0Z3012916 Keywords : climate change * global warming * surface air temperature Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.223, year: 2005

  12. A statistical method to get surface level air-temperature from satellite observations of precipitable water

    Digital Repository Service at National Institute of Oceanography (India)

    Pankajakshan, T.; Shikauchi, A.; Sugimori, Y.; Kubota, M.

    humidity within the first 50 meters of the air-sea boundary layer (Friehe and Schmitt, 1976; Liu et al., 1979). Sea surface temperature derived from NOAA-AVHRR infrared channels, using MCSST/CPSST algorithms, has an attainable accuracy of ±0.5°C (McClain et... al., 1985; Walton, 1988; Sakaida and Kawamura, 1992). The operational U.S. DMSP-SSMI provide the surface level wind speed and integrated column water vapor (precipitable water) within an accuracy comparable to in situ observations (Wentz et al., 1986...

  13. Response of surface air temperature to small-scale land clearing across latitudes

    International Nuclear Information System (INIS)

    Climate models simulating continental scale deforestation suggest a warming effect of land clearing on the surface air temperature in the tropical zone and a cooling effect in the boreal zone due to different control of biogeochemical and biophysical processes. Ongoing land-use/cover changes mostly occur at local scales (hectares), and it is not clear whether the local-scale deforestation will generate temperature patterns consistent with the climate model results. Here we paired 40 and 12 flux sites with nearby weather stations in North and South America and in Eastern Asia, respectively, and quantified the temperature difference between these paired sites. Our goal was to investigate the response of the surface air temperature to local-scale (hectares) land clearing across latitudes using the surface weather stations as proxies for localized land clearing. The results show that north of 10°N, the annual mean temperature difference (open land minus forest) decreases with increasing latitude, but the temperature difference shrinks with latitude at a faster rate in the Americas [−0.079 (±0.010) °C per degree] than in Asia [−0.046 (±0.011) °C per degree]. Regression of the combined data suggests a transitional latitude of about 35.5°N that demarks deforestation warming to the south and cooling to the north. The warming in latitudes south of 35°N is associated with increase in the daily maximum temperature, with little change in the daily minimum temperature while the reverse is true in the boreal latitudes. (paper)

  14. Improved Determination of Surface and Atmospheric Temperatures Using Only Shortwave AIRS Channels

    Science.gov (United States)

    Susskind,Joel

    2009-01-01

    AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. AIRS is a grating spectrometer with a number of linear arrays of detectors with each detector sensitive to outgoing radiation in a characteristic frequency v(sub i) with a spectral band pass delta v(sub i) of roughly v(sub i) /1200. AIRS contains 2378 spectral channels covering portions of the spectral region 650 cm(exp -1) (15.38 gm) - 2665 cm(exp -1)' (3.752 micrometers). These spectral regions contain significant absorption features from two CO2 absorption bands, the 15 micrometer (longwave) CO2 band, and the 4.3 micrometer (shortwave) CO, absorption band. There are also two atmospheric window regions, the 12 micrometerm - 8 micrometer (longwave) window, and the 4.17 micrometer - 3.75 micrometer (shortwave) window. Historically, determination of surface and atmospheric temperatures from satellite observations was performed using primarily observations in the longwave window and CO2 absorption regions. One reason for this was concerns about the effects, during the day, of reflected sunlight and non-Local Thermodynamic Equilibrium (non-LTE) on the observed radiances in the shortwave portion of the spectrum. According to cloud clearing theory, more accurate soundings of both surface skin and atmospheric temperatures can be obtained under partial cloud cover conditions if one uses the longwave channels to determine cloud cleared radiances R(sub i) for all channels, and uses R(sub i) only from shortwave channels in the determination of surface and atmospheric temperatures. This procedure is now being used by the AIRS Science Team in preparation for the AIRS Version 6 Retrieval Algorithm. This paper describes how the effects on the radiances of solar radiation reflected by clouds and the Earth's surface, and also of non-LTE, are accounted for in the analysis of the data. Results are presented for both

  15. Semi-analytical analysis of the response of the air temperature over the land surface to the global vegetation distribution

    Institute of Scientific and Technical Information of China (English)

    LIU Fei; CHAO JiPing

    2009-01-01

    Response of the air temperature over the land surface to the global vegetation distribution is investigated, using a three-dimensional governing equation to simulate the steady, large-scale, limited amplitude perturbation of the free, inviscid and adiabatic atmosphere. The adoption of the static equation leads to a temperature governing equation in the terrain following coordinate. With the prescribed temperature as the upper boundary condition and the radiation balance as the lower boundary condition, the semi-analytical solution of the global circulation temperature can be calculated. In this article, only the air temperature (at 2 m height) over the land surface is analyzed, and the result suggests that this model can simulate the air temperature pattern over the land surface reasonably. A better simulation occurs when a simple feedback of the albedo on the temperature is included. Two sensitivity experiments are analyzed through this model. One suggests that the air temperature over the land surface descends obviously when the land surface is covered with ice all over, while another suggests that the air temperature rises a little when the land surface is covered with forest except the ice-covered area. This model appears to be a good tool to study the response of the air temperature to the vegetation distribution. Limitations of the model are also discussed.

  16. An updated global grid point surface air temperature anomaly data set: 1851--1990

    Energy Technology Data Exchange (ETDEWEB)

    Sepanski, R.J.; Boden, T.A.; Daniels, R.C.

    1991-10-01

    This document presents land-based monthly surface air temperature anomalies (departures from a 1951--1970 reference period mean) on a 5{degree} latitude by 10{degree} longitude global grid. Monthly surface air temperature anomalies (departures from a 1957--1975 reference period mean) for the Antarctic (grid points from 65{degree}S to 85{degree}S) are presented in a similar way as a separate data set. The data were derived primarily from the World Weather Records and the archives of the United Kingdom Meteorological Office. This long-term record of temperature anomalies may be used in studies addressing possible greenhouse-gas-induced climate changes. To date, the data have been employed in generating regional, hemispheric, and global time series for determining whether recent (i.e., post-1900) warming trends have taken place. This document also presents the monthly mean temperature records for the individual stations that were used to generate the set of gridded anomalies. The periods of record vary by station. Northern Hemisphere station data have been corrected for inhomogeneities, while Southern Hemisphere data are presented in uncorrected form. 14 refs., 11 figs., 10 tabs.

  17. Rapid fluctuations of the air and surface temperature in the city of Bucharest (Romania)

    Science.gov (United States)

    Cheval, Sorin; Dumitrescu, Alexandru; Hustiu, Mihaita-Cristinel

    2016-04-01

    Urban areas derive significant changes of the ambient temperature generating specific challenges for society and infrastructure. Extreme temperature events, heat and cold waves affect the human comfort, increase the health risk, and require specific building regulations and emergency preparedness, strongly related to the magnitude and frequency of the thermal hazards. Rapid changes of the temperature put a particular stress for the urban settlements, and the topic has been approached constantly in the scientific literature. Due to its geographical position in a plain area with a temperate climate and noticeable continental influence, the city of Bucharest (Romania) deals with high seasonal and daily temperature variations. However, rapid fluctuations also occur at sub-daily scale caused by cold or warm air advections or by very local effects (e.g. radiative heat exchange, local precipitation). For example, in the area of Bucharest, the cold fronts of the warm season may trigger temperature decreasing up to 10-15 centigrades / hour, while warm advections lead to increasing of 1-2 centigrades / hour. This study focuses on the hourly and sub-hourly temperature variations over the period November 2014 - February 2016, using air temperature data collected from urban sensors and meteorological stations of the national network, and land surface temperature data obtained from satellite remote sensing. The analysis returns different statistics, such as magnitude, intensity, frequency, simultaneous occurrence and areal coverage of the rapid temperature fluctuations. Furthermore, the generating factors for each case study are assessed, and the results are used to define some preliminary patterns and enhance the urban temperature forecast at fine scale. The study was funded by the Romanian Programme Partnership in Priority Domains, PN - II - PCCA - 2013 - 4 - 0509 - Reducing UHI effects to improve urban comfort and balance energy consumption in Bucharest (REDBHI).

  18. Solar Cycle and Anthropogenic Forcing of Surface-Air Temperature at Armagh Observatory, Northern Ireland

    Science.gov (United States)

    Wilson, Robert M.

    2010-01-01

    A comparison of 10-yr moving average (yma) values of Armagh Observatory (Northern Ireland) surface-air temperatures with selected solar cycle indices (sunspot number (SSN) and the Aa geomagnetic index (Aa)), sea-surface temperatures in the Nino 3.4 region, and Mauna Loa carbon dioxide (CO2) (MLCO2) atmospheric concentration measurements reveals a strong correlation (r = 0.686) between the Armagh temperatures and Aa, especially, prior to about 1980 (r = 0.762 over the interval of 1873-1980). For the more recent interval 1963-2003, the strongest correlation (r = 0.877) is between Armagh temperatures and MLCO2 measurements. A bivariate fit using both Aa and Mauna Loa values results in a very strong fit (r = 0.948) for the interval 1963-2003, and a trivariate fit using Aa, SSN, and Mauna Loa values results in a slightly stronger fit (r = 0.952). Atmospheric CO2 concentration now appears to be the stronger driver of Armagh surface-air temperatures. An increase of 2 C above the long-term mean (9.2 C) at Armagh seems inevitable unless unabated increases in anthropogenic atmospheric gases can be curtailed. The present growth in 10-yma Armagh temperatures is about 0.05 C per yr since 1982. The present growth in MLCO2 is about 0.002 ppmv, based on an exponential fit using 10-yma values, although the growth appears to be steepening, thus, increasing the likelihood of deleterious effects attributed to global warming.

  19. Regression analysis in modeling of air surface temperature and factors affecting its value in Peninsular Malaysia

    Science.gov (United States)

    Rajab, Jasim Mohammed; Jafri, Mohd. Zubir Mat; Lim, Hwee San; Abdullah, Khiruddin

    2012-10-01

    This study encompasses air surface temperature (AST) modeling in the lower atmosphere. Data of four atmosphere pollutant gases (CO, O3, CH4, and H2O) dataset, retrieved from the National Aeronautics and Space Administration Atmospheric Infrared Sounder (AIRS), from 2003 to 2008 was employed to develop a model to predict AST value in the Malaysian peninsula using the multiple regression method. For the entire period, the pollutants were highly correlated (R=0.821) with predicted AST. Comparisons among five stations in 2009 showed close agreement between the predicted AST and the observed AST from AIRS, especially in the southwest monsoon (SWM) season, within 1.3 K, and for in situ data, within 1 to 2 K. The validation results of AST with AST from AIRS showed high correlation coefficient (R=0.845 to 0.918), indicating the model's efficiency and accuracy. Statistical analysis in terms of β showed that H2O (0.565 to 1.746) tended to contribute significantly to high AST values during the northeast monsoon season. Generally, these results clearly indicate the advantage of using the satellite AIRS data and a correlation analysis study to investigate the impact of atmospheric greenhouse gases on AST over the Malaysian peninsula. A model was developed that is capable of retrieving the Malaysian peninsulan AST in all weather conditions, with total uncertainties ranging between 1 and 2 K.

  20. Statistical analysis of global surface air temperature and sea level using cointegration methods

    DEFF Research Database (Denmark)

    Schmith, Torben; Johansen, Søren; Thejll, Peter

    Global sea levels are rising which is widely understood as a consequence of thermal expansion and melting of glaciers and land-based ice caps. Due to physically-based models being unable to simulate observed sea level trends, semi-empirical models have been applied as an alternative for projecting...... of future sea levels. There is in this, however, potential pitfalls due to the trending nature of the time series. We apply a statistical method called cointegration analysis to observed global sea level and surface air temperature, capable of handling such peculiarities. We find a relationship...... between sea level and temperature and find that temperature causally depends on the sea level, which can be understood as a consequence of the large heat capacity of the ocean. We further find that the warming episode in the 1940s is exceptional in the sense that sea level and warming deviates from the...

  1. Projected increases in near-surface air temperature over Ontario, Canada: a regional climate modeling approach

    Science.gov (United States)

    Wang, Xiuquan; Huang, Guohe; Liu, Jinliang

    2015-09-01

    As the biggest economy in Canada, the Province of Ontario is now suffering many consequences caused by or associated with global warming, such as frequent and intense heat waves, floods, droughts, and wind gust. Planning of mitigation and adaptation strategies against the changing climate, which requires a better understanding of possible future climate outcomes over the Province in the context of global warming, is of great interest to local policy makers, stakeholders, and development practitioners. Therefore, in this study, high-resolution projections of near-surface air temperature outcomes including mean, maximum, and minimum daily temperature over Ontario are developed, aiming at investigating how the global warming would affect the local climatology of the major cities as well as the spatial patterns of air temperature over the entire Province. The PRECIS modeling system is employed to carry out regional climate ensemble simulations driven by the boundary conditions of a five-member HadCM3-based perturbed-physics ensemble (i.e., HadCM3Q0, Q3, Q10, Q13, and Q15). The ensemble simulations are then synthesized through a Bayesian hierarchical model to develop probabilistic projections of future temperature outcomes with consideration of some uncertain parameters involved in the regional climate modeling process. The results suggest that there would be a consistent increasing trend in the near-surface air temperature with time periods from 2030s to 2080s. The most likely mean temperature in next few decades (i.e., 2030s) would be [-2, 2] °C in northern Ontario, [2, 6] °C in the middle, and [6, 12] °C in the south, afterwards the mean temperature is likely to keep rising by ~ 2 °C per 30-years period. The continuous warming across the Province would drive the lowest mean temperature up to 2 °C in the north and the highest mean temperature up to 16 °C in the south. In addition, the spread of the most likely ranges of future outcomes shows a consistent

  2. Estimation of Daily Air Temperature Based on MODIS Land Surface Temperature Products over the Corn Belt in the US

    Directory of Open Access Journals (Sweden)

    Linglin Zeng

    2015-01-01

    Full Text Available Air temperature (Ta is a key input in a wide range of agroclimatic applications. Moderate Resolution Imaging Spectroradiometer (MODIS Ts (Land Surface Temperature (LST products are widely used to estimate daily Ta. However, only daytime LST (Ts-day or nighttime LST (Ts-night data have been used to estimate Tmax/Tmin (daily maximum or minimum air temperature, respectively. The relationship between Tmax and Ts-night, and the one between Tmin and Ts-day has not been studied. In this study, both the ability of Ts-night data to estimate Tmax and the ability of Ts-day data to estimate Tmin were tested and studied in the Corn Belt during the growing season (May–September from 2008 to 2012, using MODIS daily LST products from both Terra and Aqua. The results show that using Ts-night for estimating Tmax could result in a higher accuracy than using Ts-day for a similar estimate. Combining Ts-day and Ts-night, the estimation of Tmax was improved by 0.19–1.85, 0.37–1.12 and 0.26–0.93 °C for crops, deciduous forest and developed areas, respectively, when compared with using only Ts-day or Ts-night data. The main factors influencing the Ta estimation errors spatially and temporally were analyzed and discussed, such as satellite overpassing time, air masses, irrigation, etc.

  3. Recent Improvements in Retrieving Near-Surface Air Temperature and Humidity Using Microwave Remote Sensing

    Science.gov (United States)

    Roberts, J. Brent

    2010-01-01

    Detailed studies of the energy and water cycles require accurate estimation of the turbulent fluxes of moisture and heat across the atmosphere-ocean interface at regional to basin scale. Providing estimates of these latent and sensible heat fluxes over the global ocean necessitates the use of satellite or reanalysis-based estimates of near surface variables. Recent studies have shown that errors in the surface (10 meter)estimates of humidity and temperature are currently the largest sources of uncertainty in the production of turbulent fluxes from satellite observations. Therefore, emphasis has been placed on reducing the systematic errors in the retrieval of these parameters from microwave radiometers. This study discusses recent improvements in the retrieval of air temperature and humidity through improvements in the choice of algorithms (linear vs. nonlinear) and the choice of microwave sensors. Particular focus is placed on improvements using a neural network approach with a single sensor (Special Sensor Microwave/Imager) and the use of combined sensors from the NASA AQUA satellite platform. The latter algorithm utilizes the unique sampling available on AQUA from the Advanced Microwave Scanning Radiometer (AMSR-E) and the Advanced Microwave Sounding Unit (AMSU-A). Current estimates of uncertainty in the near-surface humidity and temperature from single and multi-sensor approaches are discussed and used to estimate errors in the turbulent fluxes.

  4. Multiyear predictability of Northern Hemisphere surface air temperature in the Kiel Climate Model

    Science.gov (United States)

    Wu, Y.; Latif, M.; Park, W.

    2016-08-01

    The multiyear predictability of Northern Hemisphere surface air temperature (SAT) is examined in a multi-millennial control integration of the Kiel Climate Model, a coupled ocean-atmosphere-sea ice general circulation model. A statistical method maximizing average predictability time (APT) is used to identify the most predictable SAT patterns in the model. The two leading APT modes are much localized and the physics are discussed that give rise to the enhanced predictability of SAT in these limited regions. Multiyear SAT predictability exists near the sea ice margin in the North Atlantic and mid-latitude North Pacific sector. Enhanced predictability in the North Atlantic is linked to the Atlantic Multidecadal Oscillation and to the sea ice changes. In the North Pacific, the most predictable SAT pattern is characterized by a zonal band in the western and central mid-latitude Pacific. This pattern is linked to the Pacific Decadal Oscillation, which drives sea surface temperature anomalies. The temperature anomalies subduct into deeper ocean layers and re-emerge at the sea surface during the following winters, providing multiyear memory. Results obtained from the Coupled Model Intercomparison Project Phase 5 ensemble yield similar APT modes. Overall, the results stress the importance of ocean dynamics in enhancing predictability in the atmosphere.

  5. Multiyear predictability of Northern Hemisphere surface air temperature in the Kiel Climate Model

    Science.gov (United States)

    Wu, Y.; Latif, M.; Park, W.

    2015-10-01

    The multiyear predictability of Northern Hemisphere surface air temperature (SAT) is examined in a multi-millennial control integration of the Kiel Climate Model, a coupled ocean-atmosphere-sea ice general circulation model. A statistical method maximizing average predictability time (APT) is used to identify the most predictable SAT patterns in the model. The two leading APT modes are much localized and the physics are discussed that give rise to the enhanced predictability of SAT in these limited regions. Multiyear SAT predictability exists near the sea ice margin in the North Atlantic and mid-latitude North Pacific sector. Enhanced predictability in the North Atlantic is linked to the Atlantic Multidecadal Oscillation and to the sea ice changes. In the North Pacific, the most predictable SAT pattern is characterized by a zonal band in the western and central mid-latitude Pacific. This pattern is linked to the Pacific Decadal Oscillation, which drives sea surface temperature anomalies. The temperature anomalies subduct into deeper ocean layers and re-emerge at the sea surface during the following winters, providing multiyear memory. Results obtained from the Coupled Model Intercomparison Project Phase 5 ensemble yield similar APT modes. Overall, the results stress the importance of ocean dynamics in enhancing predictability in the atmosphere.

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

    Science.gov (United States)

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

    2016-04-01

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

  7. Paleoclimatic reconstructions in western Canada from borehole temperature logs: surface air temperature forcing and groundwater flow

    Czech Academy of Sciences Publication Activity Database

    Majorowicz, J.; Grasby, S. E.; Ferguson, G.; Šafanda, Jan; Skinner, W.

    2006-01-01

    Roč. 2, č. 1 (2006), s. 1-10. ISSN 1814-9324 Institutional research plan: CEZ:AV0Z30120515 Keywords : palaeoclimatic reconstructions * Canada * borehole temperatures Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  8. Relating trends in land surface-air temperature difference to soil moisture and evapotranspiration

    Science.gov (United States)

    Veal, Karen; Taylor, Chris; Gallego-Elvira, Belen; Ghent, Darren; Harris, Phil; Remedios, John

    2016-04-01

    Soil water is central to both physical and biogeochemical processes within the Earth System. Drying of soils leads to evapotranspiration (ET) becoming limited or "water-stressed" and is accompanied by rises in land surface temperature (LST), land surface-air temperature difference (delta T), and sensible heat flux. Climate models predict sizable changes to the global water cycle but there is variation between models in the time scale of ET decay during dry spells. The e-stress project is developing novel satellite-derived diagnostics to assess the ability of Earth System Models (ESMs) to capture behaviour that is due to soil moisture controls on ET. Satellite records of LST now extend 15 years or more. MODIS Terra LST is available from 2000 to the present and the Along-Track Scanning Radiometer (ATSR) LST record runs from 1995 to 2012. This paper presents results from an investigation into the variability and trends in delta T during the MODIS Terra mission. We use MODIS Terra and MODIS Aqua LST and ESA GlobTemperature ATSR LST with 2m air temperatures from reanalyses to calculate trends in delta T and "water-stressed" area. We investigate the variability of delta T in relation to soil moisture (ESA CCI Passive Daily Soil Moisture), vegetation (MODIS Monthly Normalized Difference Vegetation Index) and precipitation (TRMM Multi-satellite Monthly Precipitation) and compare the temporal and spatial variability of delta T with model evaporation data (GLEAM). Delta T anomalies show significant negative correlations with soil moisture, in different seasons, in several regions across the planet. Global mean delta T anomaly is small (magnitude mostly less than 0.2 K) between July 2002 and July 2008 and decreases to a minimum in early 2010. The reduction in delta T anomaly coincides with an increase in soil moisture anomaly and NDVI anomaly suggesting an increase in evapotranspiration and latent heat flux with reduced sensible heat flux. In conclusion there have been

  9. Variation in surface air temperature of China during the 20th century

    Science.gov (United States)

    Soon, Willie; Dutta, Koushik; Legates, David R.; Velasco, Victor; Zhang, Weijia

    2011-10-01

    The 20th century surface air temperature (SAT) records of China from various sources are analyzed using data which include the recently released Twentieth Century Reanalysis Project dataset. Two key features of the Chinese records are confirmed: (1) significant 1920s and 1940s warming in the temperature records, and (2) evidence for a persistent multidecadal modulation of the Chinese surface temperature records in co-variations with both incoming solar radiation at the top of the atmosphere as well as the modulated solar radiation reaching ground surface. New evidence is presented for this Sun-climate link for the instrumental record from 1880 to 2002. Additionally, two non-local physical aspects of solar radiation-induced modulation of the Chinese SAT record are documented and discussed.Teleconnections that provide a persistent and systematic modulation of the temperature response of the Tibetan Plateau and/or the tropospheric air column above the Eurasian continent (e.g., 30°N-70°N; 0°-120°E) are described. These teleconnections may originate from the solar irradiance-Arctic-North Atlantic overturning circulation mechanism proposed by Soon (2009). Also considered is the modulation of large-scale land-sea thermal contrasts both in terms of meridional and zonal gradients between the subtropical western Pacific and mid-latitude North Pacific and the continental landmass of China. The Circum-global teleconnection (CGT) pattern of summer circulation of Ding and Wang (2005) provides a physical framework for study of the Sun-climate connection over East Asia. Our results highlight the importance of solar radiation reaching the ground and the concomitant importance of changes in atmospheric transparency or cloudiness or both in motivating a true physical explanation of any Sun-climate connection. We conclude that ground surface solar radiation is an important modulating factor for Chinese SAT changes on multidecadal to centennial timescales. Therefore, a

  10. Estimation of sampling error uncertainties in observed surface air temperature change in China

    Science.gov (United States)

    Hua, Wei; Shen, Samuel S. P.; Weithmann, Alexander; Wang, Huijun

    2016-06-01

    This study examines the sampling error uncertainties in the monthly surface air temperature (SAT) change in China over recent decades, focusing on the uncertainties of gridded data, national averages, and linear trends. Results indicate that large sampling error variances appear at the station-sparse area of northern and western China with the maximum value exceeding 2.0 K2 while small sampling error variances are found at the station-dense area of southern and eastern China with most grid values being less than 0.05 K2. In general, the negative temperature existed in each month prior to the 1980s, and a warming in temperature began thereafter, which accelerated in the early and mid-1990s. The increasing trend in the SAT series was observed for each month of the year with the largest temperature increase and highest uncertainty of 0.51 ± 0.29 K (10 year)-1 occurring in February and the weakest trend and smallest uncertainty of 0.13 ± 0.07 K (10 year)-1 in August. The sampling error uncertainties in the national average annual mean SAT series are not sufficiently large to alter the conclusion of the persistent warming in China. In addition, the sampling error uncertainties in the SAT series show a clear variation compared with other uncertainty estimation methods, which is a plausible reason for the inconsistent variations between our estimate and other studies during this period.

  11. Variation in summer surface air temperature over Northeast Asia and its associated circulation anomalies

    Science.gov (United States)

    Chen, Wei; Hong, Xiaowei; Lu, Riyu; Jin, Aifen; Jin, Shizhu; Nam, Jae-Cheol; Shin, Jin-Ho; Goo, Tae-Young; Kim, Baek-Jo

    2016-01-01

    This study investigates the interannual variation of summer surface air temperature over Northeast Asia (NEA) and its associated circulation anomalies. Two leading modes for the temperature variability over NEA are obtained by EOF analysis. The first EOF mode is characterized by a homogeneous temperature anomaly over NEA and therefore is called the NEA mode. This anomaly extends from southeast of Lake Baikal to Japan, with a central area in Northeast China. The second EOF mode is characterized by a seesaw pattern, showing a contrasting distribution between East Asia (specifically including the Changbai Mountains in Northeast China, Korea, and Japan) and north of this region. This mode is named the East Asia (EA) mode. Both modes contribute equivalently to the temperature variability in EA. The two leading modes are associated with different circulation anomalies. A warm NEA mode is associated with a positive geopotential height anomaly over NEA and thus a weakened upper-tropospheric westerly jet. On the other hand, a warm EA mode is related to a positive height anomaly over EA and a northward displaced jet. In addition, the NEA mode tends to be related to the Eurasian teleconnection pattern, while the EA mode is associated with the East Asia-Pacific/Pacific-Japan pattern.

  12. Global fields of soil moisture and land surface evapotranspiration derived from observed precipitation and surface air temperature

    Science.gov (United States)

    Mintz, Y.; Walker, G. K.

    1993-01-01

    The global fields of normal monthly soil moisture and land surface evapotranspiration are derived with a simple water budget model that has precipitation and potential evapotranspiration as inputs. The precipitation is observed and the potential evapotranspiration is derived from the observed surface air temperature with the empirical regression equation of Thornthwaite (1954). It is shown that at locations where the net surface radiation flux has been measured, the potential evapotranspiration given by the Thornthwaite equation is in good agreement with those obtained with the radiation-based formulations of Priestley and Taylor (1972), Penman (1948), and Budyko (1956-1974), and this provides the justification for the use of the Thornthwaite equation. After deriving the global fields of soil moisture and evapotranspiration, the assumption is made that the potential evapotranspiration given by the Thornthwaite equation and by the Priestley-Taylor equation will everywhere be about the same; the inverse of the Priestley-Taylor equation is used to obtain the normal monthly global fields of net surface radiation flux minus ground heat storage. This and the derived evapotranspiration are then used in the equation for energy conservation at the surface of the earth to obtain the global fields of normal monthly sensible heat flux from the land surface to the atmosphere.

  13. Correlation between δ18O in precipitation and surface air temperature on different time-scale in China

    International Nuclear Information System (INIS)

    The relation between isotopic compositions of precipitation and surface air temperature provides a unique tool for paleoclimate studies, among which the relation between long term changes in δ18O of precipitation and surface air temperature at different stations or in a given location seems to be the most appropriate to paleoclimatic reconstructions. Analysis was conducted on monthly and annual mean δ18O content of precipitation and surface air temperature at spatial and fixed locations by using the data of China (1985-2002) in Global Network of Isotopes in Precipitation (GNIP) Database. This study shows that there is a positive correlation between δ18O of precipitation and surface air temperature for stations located in north of 34 degree-36 degree N latitudes. The seasonal δ18O-temperature gradient derived from the monthly data of 12 stations in northern China is about 0.034% degree C-1. The δ18O-temperature gradient, however, derived from the long term annual mean data of 13 stations, is about 0.052% degree C-1, which is substantially larger than the seasonal gradient. (authors)

  14. Surface air temperature variability and trends in the Arctic: new amplification assessment and regionalisation

    Directory of Open Access Journals (Sweden)

    Ola M. Johannessen

    2016-05-01

    Full Text Available Arctic amplification of temperature change is theorised to be an important feature of the Earth's climate system. For observational assessment and understanding of mechanisms of this amplification, which remain uncertain, thorough and detailed analyses of surface air temperature (SAT variability and trends in the Arctic are needed. Here we present an analysis of Arctic SAT variability in comparison with mid-latitudes and the Northern Hemisphere (NH, based on an advanced SAT dataset – NansenSAT. We define an index for the Arctic amplification as the ratio between absolute values of the Arctic (65–90°N and NH 30-yr running linear SAT trends. It is demonstrated that the temperature amplification in the Arctic is characteristic not only for the recent warming but also the early 20th century warming (ETCW and subsequent cooling. The amplification appears to be weaker during the recent warming than in the ETCW, simply because the index values reflect the more pervasive nature of the recent warming that reflects the background of anthropogenic global warming. We also produced a new Arctic regionalisation created from hierarchical cluster analysis, which identifies six major natural regions in the Arctic that reflect SAT variability. Statistical comparison with several climate indices shows that the Atlantic Multidecadal Oscillation (AMO is the mode of variability that is most significantly associated with the amplified warming–cooling in the Arctic, with a stronger correlation during the ETCW and recent warming than during the intermediate period. Regionally, differences are identified in terms of annual and seasonal rates of change and in their correlations with modes of variability.

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

    Science.gov (United States)

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

    2015-12-01

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

  16. Air temperature field distribution estimations over a Chinese mega-city using MODIS land surface temperature data: the case of Shanghai

    Science.gov (United States)

    Ma, Weichun; Zhou, Liguo; Zhang, Hao; Zhang, Yan; Dai, Xiaoyan

    2016-03-01

    The capability of obtaining spatially distributed air temperature data from remote sensing measurements is an improvement for many environmental applications focused on urban heat island, carbon emissions, climate change, etc. This paper is based on the MODIS/Terra and Aqua data utilized to study the effect of the urban atmospheric heat island in Shanghai, China. The correlation between retrieved MODIS land surface temperature (LST) and air temperature measured at local weather stations was initially studied at different temporal and spatial scales. Secondly, the air temperature data with spatial resolutions of 250 m and 1 km were estimated from MODIS LST data and in-situ measured air temperature. The results showed that there is a slightly higher correlation between air temperature and MODIS LST at a 250m resolution in spring and autumn on an annual scale than observed at a 1 km resolution. Although the distribution pattern of the air temperature thermal field varies in different seasons, the urban heat island (UHI) in Shanghai is characterized by a distribution pattern of multiple centers, with the central urban area as the primary center and the built-up regions in each district as the subcenters. This study demonstrates the potential not only for estimating the distribution of the air temperature thermal field from MODIS LST with 250 m resolution in spring and autumn in Shanghai, but also for providing scientific and effective methods for monitoring and studying UHI effect in a Chinese mega-city such as Shanghai.

  17. Detection and Attribution of the surface air temperature during last millennium

    Science.gov (United States)

    Peng, Dongdong; Zhou, Tianjun; Man, Wenmin

    2016-04-01

    An optimal detection method was employed to compare the reconstructed and model-simulated changes of surface air temperature during last millennium. Model simulations are from CESM1-CAM5, which include 28-member ensembles in total, i.e., 5-member ensembles volcanic forcing runs, 4-member ensembles solar forcing runs, 3-member ensembles forcing runs for land use, orbital, greenhouse gases, and 10-member ensembles runs from combined 5 individual external forcing. Analyses were conducted from hemispherical to continental scale. Results show that combined effect of all the external forcings can be detected for both Northern and Southern Hemisphere, and for the continent of Europe, Arctic and Antarctic. The influence of volcanic eruption and solar activity can be detected for all the hemispheres and nearly all the continents of North Hemisphere. Land use forcing can be detected for all the continents of Northern Hemisphere, but only detected for one continent of Southern Hemisphere, i.e., South America. The orbital forcing is detected for all the continents of Northern Hemisphere, but not detected for the Northern Hemisphere as whole. Influence of greenhouse gases can rarely be detected from hemispherical to continental scale.

  18. Variability of the Coupling Between Surface Air Temperature and Northern Annular Mode at Various Levels

    Institute of Scientific and Technical Information of China (English)

    TAN Benkui; SUO Lingling; HUANG Jiayou

    2008-01-01

    This article focuses on the variability of the coupling between surface air temperature(SAT)and northern annular mode(NAM)at various levels.To measure the coupling intensity between the SAT and the NAM anomaly fields.the coupling index has been defined as the leading principal component of the partial least squares regression model of the SAT and NAM anomalies.Both a composite analysis and the coupling index have been used to reveal level-by-level and month-to-month variability of the coupling between the upper anomalous NAM and the SAT in the Northern Hemisphere.The major results are as follows:the January SAT anomaly is more strongly coupled with the January NAM anomaly at the middle-upper tropospheric levels than that at the other levels,while the same is true for the February SAT anomaly with the January NAM anomaly at the lower stratospheric levels.The January NAM anomaly at the middleupper tropospheric levels is most strongly coupled with the January SAT anomaly,and the coupling intensity is successively reduced month by month and becomes trivial after April.The January NAM anomaly at the lower stratospheric levels is more strongly coupled with January,Febrnary and March SAT anomalies,but the coupling becomes trivial after April.

  19. Calibrating Forecasts of Surface Air Temperature over South Korea using Bayesian Model Averaging

    Science.gov (United States)

    Kim, Chansoo; Oh, Seok-Geun; Suh, Myoung-Seok

    2014-05-01

    In this study, we investigate the prospect of calibrating of probabilistic numerical forecasts of surface air temperature over South Korea by using Bayesian model averaging (BMA). The simulation results from four regional climate model (RCM) with two boundary conditions (NCEP-DOE and ERA-interim) over the CORDEX East Asia are obtained. The one month weighted ensemble outputs for the 59 stations over South Korea are calibrated using BMA method for 48 monthly time periods base on BMA weights obtained from the previous 15 months of training data. The predictive density function is calibrated using BMA and the individual forecasts are weighted according to their performance. The calibrated probabilistic forecasts are assessed using flatness of the rank histogram and residual quantile-qunatile (R-Q-Q) plot. They show that the simulation skills of the RCMs differ according to season and geographic location, but the RCMs show a systematic cold bias irrespective of season and geographic location. The results show that the application of BMA improves the calibration of the raw ensemble and other weighted ensemble mean forecasts irrespective of simulation skill of the RCM and geographic location. In addition, the deterministic-style BMA forecasts usually perform better than the deterministic forecast of the single best member.

  20. Prediction of surface air temperatures by neural network, example based on three-year temperature monitoring at Spořilov station

    Czech Academy of Sciences Publication Activity Database

    Bodri, L.; Čermák, Vladimír

    2003-01-01

    Roč. 47, č. 1 (2003), s. 173-184. ISSN 0039-3169 R&D Projects: GA AV ČR IAA3012005 Institutional research plan: CEZ:AV0Z3012916 Keywords : surface air temperatures * neural networks * temperature monitoring Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.426, year : 2003

  1. Applications of satellite data to the studies of agricultural meteorology, 2: Relationship between air temperature and surface temperature measured by infrared thermal radiometer

    International Nuclear Information System (INIS)

    Experiments were performed in order to establish interpretation keys for estimation of air temperature from satellite IR data. Field measurements were carried out over four kinds of land surfaces including seven different field crops on the university campus at Sapporo. The air temperature was compared with the surface temperature measured by infrared thermal radiometer (National ER2007, 8.5-12.5μm) and, also with other meteorological parameters (solar radiation, humidity and wind speed). Also perpendicular vegetation index (PVI) was measured to know vegetation density of lands by ho radio-spectralmeter (Figs. 1 & 2). Table 1 summarizes the measurements taken in these experiments.The correlation coefficients between air temperature and other meteorological parameters for each area are shown in Table 2. The best correlation coefficient for total data was obtained with surface temperature, and it suggests the possibility that air temperature may be estimated by satellite IR data since they are related to earth surface temperatures.Further analyses were done between air temperature and surface temperature measured with thermal infrared radiometer.The following conclusions may be drawn:(1) Air temperature from meteorological site was well correlated to surface temperature of lands that were covered with dense plant and water, for example, grass land, paddy field and rye field (Table 2).(2) The correlation coefficients and the regression equations on grass land, paddy field and rye field were almost the same (Fig. 3). The mean correlation coefficient for these three lands was 0.88 and the regression equation is given in Eq. (2).(3) There was good correlation on bare soil land also, but had large variations (Fig. 3).(4) The correlations on crop fields depend on the density of plant cover. Good correlation is obtained on dense vegetative fields.(5) Small variations about correlation coefficients were obtained for the time of day (Table 3).(6) On the other hand, large

  2. Recent changes in ground surface thermal regimes in the context of air temperature warming over the Heihe River Basin, China

    Institute of Scientific and Technical Information of China (English)

    QingFeng Wang; TingJun Zhang; XiaoQing Peng; Bin Cao

    2014-01-01

    Changes-in-ground-surface-thermal-regimes-play-a-vital-role-in-surface-and-subsurface-hydrology,-ecosystem-diversity-and-productivity,-and-global-thermal,-water-and-carbon-budgets-as-well-as-climate-change.-Estimating-spring,-summer,-autumn-and-winter-air-temperatures-and-mean-annual-air-temperature-(MAAT)-from-1960-through-2008-over-the-Heihe-River-Basin-reveals-a-statistically-significant-trend-of-0.31-°C/decade,-0.28-°C/decade,-0.37-°C/decade,-0.50-°C/decade,-and-0.37-°C-/decade,-respectively.-The-averaged-time-series-of-mean-annual-ground-surface-temperature-(MAGST)-andmaximum-annual-ground-surface-temperature(MaxAGST)-for-1972-2006-over-the-basin-indicates-a-statistically-significant-trend-of-0.58-°C/decade-and-1.27-°C/decade,-respectively.-The-minimum-annual-ground-surface-temperature-(MinAGST)-in-the-same-period-remains-unchanged-as-a-whole.-Estimating-surface-freezing/thawing-index-as-well-as-the-ratio-of-freezing-index-to-thawing-index-(RFT)in-the-period-between-1959-and-2006-over-the-basin-indicates-a-statistically-significant-trend-of-42.5-°C-day/decade,-85.4-°C-day/decade-and-0.018/decade,-respectively.

  3. Amplitude-Phase Characteristics of the Annual Cycle of Surface Air Temperature in the Northern Hemisphere

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The amplitude-phase characteristics (APC) of surface air temperature (SAT) annual cycle (AC)in the Northern Hemisphere are analyzed. From meteorological observations for the 20th century andmeteorological reanalyses for its second half, it is found that over land negative correlation of SAT ACamplitude with annual mean SAT dominates. Nevertheless, some exceptions exist. The positive correlationbetween these two variables is found over the two desert regions: in northern Africa and in Central America.Areas of positive correlations are also found for the northern Pacific and for the tropical Indian and PacificOceans. Southward of the characteristic annual mean snow-ice boundary (SIB) position, the shape ofthe SAT AC becomes more sinusoidal under climate warming. In contrast, northward of it, this shapebecomes less sinusoidal. The latter is also found for the above-mentioned two desert regions. In theFar East (southward of about 50°N), the SAT AC shifts as a whole: here its spring and autumn phasesoccur earlier if the annual mean SAT increases. From energy-balance climate considerations, those trendsfor SAT AC APC in the middle and high latitudes are associated with the influence of the albedo-SATfeedback due to the SIB movement. In the Far East the trends are attributed to the interannual cloudinessvariability, and in the desert regions, to the influence of a further desertification and/or scattering aerosolloading into the atmosphere. In the north Pacific, the exhibited trends could only be explained as aresult of the influence of the greenhouse-gases loading on atmospheric opacity. The trends for SAT ACAPC related to the SIB movement are simulated reasonably well by the climate model of intermediatecomplexity (IAP RAS CM) in the experiment with greenhouse gases atmospheric loading. In contrast,the tendencies resulting from the cloudiness variability are not reproduced by this model. The model alsopartly simulates the tendencies related to the desertification

  4. Artificial neural network approach for estimation of surface specific humidity and air temperature using Multifrequency Scanning Microwave Radiometer

    Indian Academy of Sciences (India)

    Randhir Singh; B G Vasudevan; P K Pal; P C Joshi

    2004-03-01

    Microwave sensor MSMR (Multifrequency Scanning Microwave Radiometer) data onboard Oceansat-1 was used for retrieval of monthly averages of near surface specific humidity (a) and air temperature (a) by means of Artificial Neural Network (ANN). The MSMR measures the microwave radiances in 8 channels at frequencies of 6.6, 10.7, 18 and 21 GHz for both vertical and horizontal polarizations. The artificial neural networks (ANN) technique is employed to find the transfer function relating the input MSMR observed brightness temperatures and output (a and a) parameters. Input data consist of nearly 28 months (June 1999 — September 2001) of monthly averages of MSMR observed brightness temperature and surface marine observations of a and a from Comprehensive Ocean- Atmosphere Data Set (COADS). The performance of the algorithm is assessed with independent surface marine observations. The results indicate that the combination of MSMR observed brightness temperatures as input parameters provides reasonable estimates of monthly averaged surface parameters. The global root mean square (rms) differences are 1.0°C and 1.1 g kg−1 for air temperature and surface specific humidity respectively.

  5. Spatial Correlations of Anomaly Time Series of AIRS Version-6 Land Surface Skin Temperatures with the Nino-4 Index

    Science.gov (United States)

    Susskind, Joel; Lee, Jae N.; Iredell, Lena

    2013-01-01

    The AIRS Science Team Version-6 data set is a valuable resource for meteorological studies. Quality Controlled earth's surface skin temperatures are produced on a 45 km x 45 km spatial scale under most cloud cover conditions. The same retrieval algorithm is used for all surface types under all conditions. This study used eleven years of AIRS monthly mean surface skin temperature and cloud cover products to show that land surface skin temperatures have decreased significantly in some areas and increased significantly in other areas over the period September 2002 through August 2013. These changes occurred primarily at 1:30 PM but not at 1:30 AM. Cooling land areas contained corresponding increases in cloud cover over this time period, with the reverse being true for warming land areas. The cloud cover anomaly patterns for a given month are affected significantly by El Nino/La Nina activity, and anomalies in cloud cover are a driving force behind anomalies in land surface skin temperature.

  6. Evaluation of surface air temperature trend and climate change in the north - east of I. R. of Iran

    International Nuclear Information System (INIS)

    In this paper maximum, minimum and mean surface air temperature recorded, analysed to reveal spatial and temporal patterns of long-term trends, change points, significant warming (cooling) periods and linear trend per decade. According to this research summer minimum temperatures have generally increased at a larger rate than in spring and autumn minimum temperatures. On the other hand, nighttime warming rates of spring and summer are generally stronger than those that exist in spring and summer daytime temperatures. Considering the significant increasing trends in annual, spring and summer temperatures, it is seen that night-time warming rates are stronger in the northern regions, which are characterized by the Khorasan Province macro climate type: a very hot summer, a relatively hot and late spring and early autumn, and a moderate winter. We have seriously considered the strong warming trends in spring and summer and thus likely in annual minimum air temperatures. It is very likely that significant and very rapid night-time warming trends over much of the province can be related to the widespread, rapid and increased urbanization in Khorasan Province, in addition to long-term and global effects of the human-induced climate change on air temperatures. (Author)

  7. Predicting Indian Summer Monsoon onset through variations of surface air temperature and relative humidity

    Science.gov (United States)

    Stolbova, Veronika; Surovyatkina, Elena; Kurths, Jurgen

    2015-04-01

    Indian Summer Monsoon (ISM) rainfall has an enormous effect on Indian agriculture, economy, and, as a consequence, life and prosperity of more than one billion people. Variability of the monsoonal rainfall and its onset have a huge influence on food production, agricultural planning and GDP of the country, which on 22% is determined by agriculture. Consequently, successful forecasting of the ISM onset is a big challenge and large efforts are being put into it. Here, we propose a novel approach for predictability of the ISM onset, based on critical transition theory. The ISM onset is defined as an abrupt transition from sporadious rainfall to spatially organized and temporally sustained rainfall. Taking this into account, we consider the ISM onset as is a critical transition from pre-monsoon to monsoon, which take place in time and also in space. It allows us to suggest that before the onset of ISM on the Indian subcontinent should be areas of critical behavior where indicators of the critical transitions can be detected through an analysis of observational data. First, we identify areas with such critical behavior. Second, we use detected areas as reference points for observation locations for the ISM onset prediction. Third, we derive a precursor for the ISM onset based on the analysis of surface air temperature and relative humidity variations in these reference points. Finally, we demonstrate the performance of this precursor on two observational data sets. The proposed approach allows to determine ISM onset in advance in 67% of all considered years. Our proposed approach is less effective during the anomalous years, which are associated with weak/strong monsoons, e.g. El-Nino, La-Nina or positive Indian Ocean Dipole events. The ISM onset is predicted for 23 out of 27 normal monsoon years (85%) during the past 6 decades. In the anomalous years, we show that time series analysis in both areas during the pre-monsoon period reveals indicators whether the

  8. Modeled Seasonal Variations of Firn Density Induced by Steady State Surface Air Temperature Cycle

    Science.gov (United States)

    Jun, Li; Zwally, H. Jay; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Seasonal variations of firn density in ice-sheet firn layers have been attributed to variations in deposition processes or other processes within the upper firn. A recent high-resolution (mm scale) density profile, measured along a 181 m core from Antarctica, showed small-scale density variations with a clear seasonal cycle that apparently was not-related to seasonal variations in deposition or known near-surface processes (Gerland and others 1999). A recent model of surface elevation changes (Zwally and Li, submitted) produced a seasonal variation in firn densification, and explained the seasonal surface elevation changes observed by satellite radar altimeters. In this study, we apply our 1-D time-dependent numerical model of firn densification that includes a temperature-dependent formulation of firn densification based on laboratory measurements of grain growth. The model is driven by a steady-state seasonal surface temperature and a constant accumulation rate appropriate for the measured Antarctic ice core. The modeled seasonal variations in firn density show that the layers of snow deposited during spring to mid-summer with the highest temperature history compress to the highest density, and the layers deposited during later summer to autumn with the lowest temperature history compress to the lowest density. The initial amplitude of the seasonal difference of about 0.13 reduces to about 0.09 in five years and asymptotically to 0.92 at depth, which is consistent with the core measurements.

  9. Spatiotemporal changes in extreme ground surface temperatures and the relationship with air temperatures in the Three-River Source Regions during 1980-2013

    Science.gov (United States)

    Luo, Dongliang; Jin, Huijun; Lü, Lanzhi; Zhou, Jian

    2016-02-01

    Climate changes are affecting plant growth, ecosystem evolution, hydrological processes, and water resources in the Three-River Source Regions (TRSR). Daily ground surface temperature (GST) and air temperature (Ta) recordings from 12 meteorological stations illustrated trends and characteristics of extreme GST and Ta in the TRSR during 1980-2013. We used the Mann-Kendall test and Sen's slope estimate to analyze 12 temperature extreme indices as recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI). The mean annual ground surface temperatures (MAGST) are 2.4-4.3 °C higher than the mean annual air temperatures (MAAT) in the TRSR. The increasing trends of the MAGST are all higher than those of the MAAT. The multi-year average maximum GST (28.1 °C) is much higher than that of the Ta (7.6 °C), while the minimum GST (-8.7 °C) is similar to that of the minimum Ta (-6.9 °C). The minimum temperature trends are more significant than those of the maximum temperature and are consistent with temperature trends in other regions of China. Different spatiotemporal patterns of GST extremes compared to those of Ta may result from greater warming of the ground surface. Consequently, the difference between the GST and Ta increased. These findings have implications for variations of surface energy balance, sensible heat flux, ecology, hydrology, and permafrost.

  10. LINKS BETWEEN ATMOSPHERIC CIRCULATION AND SURFACE AIR TEMPERATURE IN REGIONAL CLIMATE MODELS

    Czech Academy of Sciences Publication Activity Database

    Plavcová, Eva; Kyselý, Jan

    Patras: University of Patras, 2010 - (Argiriou, A.; Kazantzidis, A.), s. 825-832 ISBN 978-960-99254-0-2. [International Conference of Meteorology, Climatology and Atmospheric Physics (COMECAP2010) /10./. Patras (GR), 25.05.2010-28.05.2010] R&D Projects: GA ČR GAP209/10/2265 Grant ostatní: ENSEMBLES(XE) 505539 Institutional research plan: CEZ:AV0Z30420517 Keywords : regional climate model * daily air temperature * atmospheric circulation * Central Europe Subject RIV: DG - Athmosphere Sciences, Meteorology

  11. Air temperature field distribution estimations over a Chinese mega-city using MODIS land surface temperature data: the case of Shanghai

    Institute of Scientific and Technical Information of China (English)

    Weichun MA; Liguo ZHOU; Hao ZHANG; Yan ZHANG; Xiaoyan DAI

    2016-01-01

    The capability of obtaining spatially distributed air temperature data from remote sensing measurements is an improvement for many environmental applications focused on urban heat island,carbon emissions,climate change,etc.This paper is based on the MODIS/Terra and Aqua data utilized to study the effect of the urban atmospheric heat island in Shanghai,China.The correlation between retrieved MODIS land surface temperature (LST) and air temperature measured at local weather stations was initially studied at different temporal and spatial scales.Secondly,the air temperature data with spatial resolutions of 250 m and 1 km were estimated from MODIS LST data and in-situ measured air temperature.The results showed that there is a slightly higher correlation between air temperature and MODIS LST at a 250 m resolution in spring and autumn on an annual scale than observed at a 1 km resolution.Although the distribution pattern of the air temperature thermal field varies in different seasons,the urban heat island (UHI) in Shanghai is characterized by a distribution pattern of multiple centers,with the central urban area as the primary center and the built-up regions in each district as the subcenters.This study demonstrates the potential not only for estimating the distribution of the air temperature thermal field from MODIS LST with 250 m resolution in spring and autumn in Shanghai,but also for providing scientific and effective methods for monitoring and studying UHI effect in a Chinese mega-city such as Shanghai.

  12. Periodicities between 6 and 16 years in surface air temperature in possible relation to solar inertial motion

    Czech Academy of Sciences Publication Activity Database

    Charvátová, Ivanka; Střeštík, Jaroslav

    2004-01-01

    Roč. 66, č. 3 (2004), s. 219-227. ISSN 1364-6826 R&D Projects: GA ČR GA205/97/0921; GA AV ČR KSK3012103 Institutional research plan: CEZ:AV0Z3012916 Keywords : solar motion * surface air temperature * climatic change Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.517, year: 2004

  13. The Influence of Stratospheric Sulphate Aerosol Deployment on the Surface Air Temperature and the Risk of an Abrupt Global Warming

    OpenAIRE

    Roland von Glasow; Jones, Phil D.; Pedro Llanillo

    2010-01-01

    We used the ‘Radiative-Convective Model of the Earth-atmosphere system’ (OGIM) to investigate the cooling effects induced by sulphur injections into the stratosphere. The ensemble of numerical calculations was based on the A1B scenario from the IPCC Special Report on Emissions Scenarios (SRES). Several geoengineered scenarios were analysed, including the abrupt interruption of these injections in different scenarios and at different dates. We focused on the surface air temperature (SAT) anoma...

  14. Exchange of Groundwater and Surface-Water Mediated by Permafrost Response to Seasonal and Long Term Air Temperature Variation

    Science.gov (United States)

    Ge, Shemin; McKenzie, Jeffrey; Voss, Clifford; Wu, Qingbai

    2011-01-01

    Permafrost dynamics impact hydrologic cycle processes by promoting or impeding groundwater and surface water exchange. Under seasonal and decadal air temperature variations, permafrost temperature changes control the exchanges between groundwater and surface water. A coupled heat transport and groundwater flow model, SUTRA, was modified to simulate groundwater flow and heat transport in the subsurface containing permafrost. The northern central Tibet Plateau was used as an example of model application. Modeling results show that in a yearly cycle, groundwater flow occurs in the active layer from May to October. Maximum groundwater discharge to the surface lags the maximum subsurface temperature by two months. Under an increasing air temperature scenario of 3?C per 100 years, over the initial 40-year period, the active layer thickness can increase by three-fold. Annual groundwater discharge to the surface can experience a similar three-fold increase in the same period. An implication of these modeling results is that with increased warming there will be more groundwater flow in the active layer and therefore increased groundwater discharge to rivers. However, this finding only holds if sufficient upgradient water is available to replenish the increased discharge. Otherwise, there will be an overall lowering of the water table in the recharge portion of the catchment.

  15. Evaluation of air-soil temperature relationships simulated by land surface models during winter across the permafrost region

    Science.gov (United States)

    Wang, Wenli; Rinke, Annette; Moore, John C.; Ji, Duoying; Cui, Xuefeng; Peng, Shushi; Lawrence, David M.; McGuire, A. David; Burke, Eleanor J.; Chen, Xiaodong; Delire, Christine; Koven, Charles; MacDougall, Andrew; Saito, Kazuyuki; Zhang, Wenxin; Alkama, Ramdane; Bohn, Theodore J.; Ciais, Philippe; Decharme, Bertrand; Gouttevin, Isabelle; Hajima, Tomohiro; Krinner, Gerhard; Lettenmaier, Dennis P.; Miller, Paul A.; Smith, Benjamin; Sueyoshi, Tetsuo

    2016-01-01

     A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyze simulated relationships between air and near-surface (20 cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models and compare them with observations from 268 Russian stations. There are large across-model differences as expressed by simulated differences between near-surface soil and air temperatures, (ΔT), of 3 to 14 K, in the gradients between soil and air temperatures (0.13 to 0.96°C/°C), and in the relationship between ΔT and snow depth. The observed relationship between ΔT and snow depth can be used as a metric to evaluate the effects of each model's representation of snow insulation, and hence guide improvements to the model’s conceptual structure and process parameterizations. Models with better performance apply multi-layer snow schemes and consider complex snow processes. Some models show poor performance in representing snow insulation due to underestimation of snow depth and/or overestimation of snow conductivity. Generally, models identified as most acceptable with respect to snow insulation simulate reasonable areas of near-surface permafrost (12–16 million km2). However, there is not a simple relationship between the quality of the snow insulation in the acceptable models and the simulated area of Northern Hemisphere near-surface permafrost, likely because several other factors such as differences in the treatment of soil organic matter, soil hydrology, surface energy calculations, and vegetation also provide important controls on simulated permafrost distribution.

  16. Evaluation of air-soil temperature relationships simulated by land surface models during winter across the permafrost region

    Science.gov (United States)

    Wang, Wenli; Rinke, Annette; Moore, John C.; Ji, Duoying; Cui, Xuefeng; Peng, Shushi; Lawrence, David M.; McGuire, A. David; Burke, Eleanor J.; Chen, Xiaodong; Decharme, Bertrand; Koven, Charles; MacDougall, Andrew; Saito, Kazuyuki; Zhang, Wenxin; Alkama, Ramdane; Bohn, Theodore J.; Ciais, Philippe; Delire, Christine; Gouttevin, Isabelle; Hajima, Tomohiro; Krinner, Gerhard; Lettenmaier, Dennis P.; Miller, Paul A.; Smith, Benjamin; Sueyoshi, Tetsuo; Sherstiukov, Artem B.

    2016-08-01

    A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyse simulated relationships between air and near-surface (20 cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models, and compare them with observations from 268 Russian stations. There are large cross-model differences in the simulated differences between near-surface soil and air temperatures (ΔT; 3 to 14 °C), in the sensitivity of soil-to-air temperature (0.13 to 0.96 °C °C-1), and in the relationship between ΔT and snow depth. The observed relationship between ΔT and snow depth can be used as a metric to evaluate the effects of each model's representation of snow insulation, hence guide improvements to the model's conceptual structure and process parameterisations. Models with better performance apply multilayer snow schemes and consider complex snow processes. Some models show poor performance in representing snow insulation due to underestimation of snow depth and/or overestimation of snow conductivity. Generally, models identified as most acceptable with respect to snow insulation simulate reasonable areas of near-surface permafrost (13.19 to 15.77 million km2). However, there is not a simple relationship between the sophistication of the snow insulation in the acceptable models and the simulated area of Northern Hemisphere near-surface permafrost, because several other factors, such as soil depth used in the models, the treatment of soil organic matter content, hydrology and vegetation cover, also affect the simulated permafrost distribution.

  17. Potential causes of differences between ground and surface air temperature warming across different ecozones in Alberta, Canada

    Science.gov (United States)

    Majorowicz, Jacek A.; Skinner, Walter R.

    1997-10-01

    Analysis and modelling of temperature anomalies from 25 selected deep wells in Alberta show that the differences between GST (ground surface temperature) warming for the northern Boreal Forest ecozone and the combined Prairie Grassland ecozone and Aspen Parkland transition region to the south occur during the latter half of this century. This corresponds with recent changes in surface albedo resulting from permanent land development in the northern areas and also to increases in natural forest fires in the past 20 years. Differences between GST and SAT (surface air temperature) warming are much higher in the Boreal Forest ecozone than in the Prairie Grassland ecozone and Aspen Parkland transition region. Various hypotheses which could account for the existing differences between the GST and SAT warming in the different ecozones of Alberta, and western Canada in general, are tested. Analysis of existing data on soil temperature, hydrological piezometric surfaces, snowfall and moisture patterns, and land clearing and forest fires, indicate that large areas of Alberta, characterised by anomalous GST warming, have experienced widespread changes to the surface landscape in this century. It is postulated that this has resulted in a lower surface albedo with a subsequent increase in the absorption of solar energy. Heat flow modelling shows that, after climatic SAT warming, permanent clearing of the land is the most effective and likely cause of the observed changes in the GST warming. The greater GST warming in the Boreal Forest ecozone in the latter half of this century is related to landscape change due to land development and increasing forest fire activity. It appears to account for a portion of the observed SAT warming in this region through a positive feedback loop with the overlying air. The anthropogenic effect on regional climatic warming through 20th century land clearing and landscape alteration requires further study. In future, more accurate quantification of

  18. The impact of the Madden-Julian oscillation on polar surface air temperature

    Science.gov (United States)

    Yoo, Changhyun

    This dissertation investigates the impact of the Madden-Julian Oscillation (MJO) on the extratropical surface air temperature (SAT). The underlying idea of this study is that tropical convective heating is linked to the extratropical circulation and SAT through poleward propagating Rossby waves. Given this perspective, two questions are addressed. One is the extent to which the MJO contribute to interdecadal time scale polar amplification of SAT (Chapters 2 and 3) and the other is the mechanism by which the MJO alters the intraseasonal time scale extratropical SAT change (Chapters 4 and 5). Polar amplification, i.e., interdecadal time-scale SAT increase being greatest at high latitudes, is one of prominent features of current climate change. Numerous observational and modeling studies have documented this phenomenon. However, its cause remains uncertain. The surface albedo feedback, which is associated with retreats in snow and ice cover and hence increases in surface albedo with a warmer climate, is the most prominent explanation. However, one of important characteristics of polar amplification is that its maximum amplitude is retained during the winter season when incoming solar radiation is minimal. In Chapters 2 and 3, we show that polar amplification during the 1979--2008 winters is tropically excited. More specifically, we show evidence that polar amplification is linked to interdecadal time scale change in the MJO phase frequency of occurrence. We present both the extended boreal winter (November to March) and austral winter (May to September), with our focus being on winter Hemisphere, where the MJO has strong influence. First, during the 30-year boreal winter, MJO phases 4--6 have occurred with an increased frequency of occurrence while phases 1 and 2 have showed a moderate decrease in their frequency of occurrence. Using lagged composites of the SAT, we show that Arctic warming takes place 1--2 weeks after MJO passes its phases 4--6. Similarly, MJO phases

  19. The impact of the Madden-Julian oscillation on polar surface air temperature

    Science.gov (United States)

    Yoo, Changhyun

    This dissertation investigates the impact of the Madden-Julian Oscillation (MJO) on the extratropical surface air temperature (SAT). The underlying idea of this study is that tropical convective heating is linked to the extratropical circulation and SAT through poleward propagating Rossby waves. Given this perspective, two questions are addressed. One is the extent to which the MJO contribute to interdecadal time scale polar amplification of SAT (Chapters 2 and 3) and the other is the mechanism by which the MJO alters the intraseasonal time scale extratropical SAT change (Chapters 4 and 5). Polar amplification, i.e., interdecadal time-scale SAT increase being greatest at high latitudes, is one of prominent features of current climate change. Numerous observational and modeling studies have documented this phenomenon. However, its cause remains uncertain. The surface albedo feedback, which is associated with retreats in snow and ice cover and hence increases in surface albedo with a warmer climate, is the most prominent explanation. However, one of important characteristics of polar amplification is that its maximum amplitude is retained during the winter season when incoming solar radiation is minimal. In Chapters 2 and 3, we show that polar amplification during the 1979--2008 winters is tropically excited. More specifically, we show evidence that polar amplification is linked to interdecadal time scale change in the MJO phase frequency of occurrence. We present both the extended boreal winter (November to March) and austral winter (May to September), with our focus being on winter Hemisphere, where the MJO has strong influence. First, during the 30-year boreal winter, MJO phases 4--6 have occurred with an increased frequency of occurrence while phases 1 and 2 have showed a moderate decrease in their frequency of occurrence. Using lagged composites of the SAT, we show that Arctic warming takes place 1--2 weeks after MJO passes its phases 4--6. Similarly, MJO phases

  20. Low-frequency variability of surface air temperature over the Barents Sea: causes and mechanisms

    Science.gov (United States)

    van der Linden, Eveline C.; Bintanja, Richard; Hazeleger, Wilco; Graversen, Rune G.

    2016-08-01

    The predominant decadal to multidecadal variability in the Arctic region is a feature that is not yet well-understood. It is shown that the Barents Sea is a key region for Arctic-wide variability. This is an important topic because low-frequency changes in the ocean might lead to large variations in the sea-ice cover, which then cause massive changes in the ocean-atmosphere heat exchanges. Here we describe the mechanism driving surface temperatures and heat fluxes in the Barents Sea based primarily on analyzes of one global coupled climate model. It is found that the ocean drives the low-frequency changes in surface temperature, whereas the atmosphere compensates the oceanic transport anomalies. The seasonal dependence and the role of individual components of the ocean-atmosphere energy budget are analyzed in detail, showing that seasonally-varying climate mechanisms play an important role. Herein, sea ice is governing the seasonal response, by acting as a lid that opens and closes during warm and cold periods, respectively, thereby modulating the surface heat fluxes.

  1. Seasonal variations of air-sea heat fluxes and sea surface temperature in the northwestern Pacific marginal seas

    Institute of Scientific and Technical Information of China (English)

    LIU Na; WU Dexing; LIN Xiaopei; MENG Qingjia

    2014-01-01

    Using a net surface heat flux (Qnet) product obtained from the objectively analyzed air-sea fluxes (OAFlux) project and the international satellite cloud climatology project (ISCCP), and temperature from the simple ocean data assimilation (SODA), the seasonal variations of the air-sea heat fluxes in the northwestern Pa-cific marginal seas (NPMS) and their roles in sea surface temperature (SST) seasonality are studied. The seasonal variations of Qnet, which is generally determined by the seasonal cycle of latent heat flux (LH), are in response to the advection-induced changes of SST over the Kuroshio and its extension. Two dynamic regimes are identified in the NPMS:one is the area along the Kuroshio and its extension, and the other is the area outside the Kuroshio. The oceanic thermal advection dominates the variations of SST and hence the sea-air humidity plays a primary role and explains the maximum heat losing along the Kuroshio. The heat transported by the Kuroshio leads to a longer period of heat losing over the Kuroshio and its Extension. Positive anomaly of heat content corresponds with the maximum heat loss along the Kuroshio. The oceanic advection controls the variations of heat content and hence the surface heat flux. This study will help us understand the mechanism controlling variations of the coupled ocean-atmosphere system in the NPMS. In the Kuroshio region, the ocean current controls the ocean temperature along the main stream of the Ku-roshio, and at the same time, forces the air-sea fluxes.

  2. Heat Transfer and Observation of Droplet-Surface Interactions During Air-Mist Cooling at CSP Secondary System Temperatures

    Science.gov (United States)

    Huerta L., Mario E.; Mejía G., M. Esther; Castillejos E., A. Humberto

    2016-04-01

    Air-mists are key elements in the secondary cooling of modern thin steel slab continuous casters. The selection of water, W, and air, A, flow rates, and pressures in pneumatic nozzles open up a wide spectrum of cooling possibilities by their influence on droplet diameter, d, droplet velocity, v, and water impact flux, w. Nonetheless, due to the harsh environment resulting from the high temperatures and dense mists involved, there is very little information about the correlation between heat flux extracted, - q, and mist characteristics, and none about the dynamics of drop-wall interactions. For obtaining both kinds of information, this work combines a steady-state heat flux measuring method with a visualization technique based on a high-speed camera and a laser illumination system. For wall temperatures, T w, between ~723 K and ~1453 K (~450 °C and ~1180 °C), which correspond to film boiling regime, it was confirmed that - q increases with increase in v, w, and T w and with decrease in d. It should be noticed, however, that the increase in w generally decreases the spray cooling effectiveness because striking drops do not evaporate efficiently due to the interference by liquid remains from previous drops. Visualization of the events happening close to the surface also reveals that the contact time of the liquid with the surface is very brief and that rebounding, splashing, sliding, and levitation of drops lead to ineffective contact with the surface. At the center of the mist footprint, where drops impinge nearly normal to the surface those with enough momentum establish intimate contact with it before forming a vapor layer that pushes away the remaining liquid. Also, some drops are observed sliding upon the surface or levitating close to it; these are drops with low momentum which are influenced by the deflecting air stream. At footprint positions where oblique impingement occurs, frequently drops are spotted sliding or levitating and liquid films flowing in

  3. Volcanic eruption events and the variations in surface air temperature over high latitude regions

    International Nuclear Information System (INIS)

    The numerical experiments of the author's study suggest that volcanic eruptions cause a cooling of the surface temperature. Special attention will be given to the climatic fluctuation tied to the cooling in summer in high latitudes resulting from the eruptions occurring in spring or summer in high latitudes in the Northern Hemisphere. In this study the radiative parameterization is used to force a one-dimensional global climate model based on the energy balance of the earth-atmosphere system, to present some interesting results. In the model the effect of the volcanic dust is expressed as a function of the optical depth and aerosol size distribution and a simple model of the latitudinal distribution of aerosol optical thickness as a function of time is developed. The sensitivity experiment results concerning the high latitude regions are described below, followed by a discussion of the reasons for these results

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

    Czech Academy of Sciences Publication Activity Database

    Plavcová, Eva; Kyselý, Jan

    2012-01-01

    Roč. 39, 7-8 (2012), s. 1681-1695. ISSN 0930-7575 R&D Projects: GA ČR GAP209/10/2265 Grant ostatní: ENSEMBLES: EU-FP6(XE) 505539 Institutional support: RVO:68378289 Keywords : Regional climate models * Global climate models * Atmospheric circulation * Surface air temperature * ENSEMBLES * Central Europe Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 4.231, year: 2012 http://link.springer.com/article/10.1007%2Fs00382-011-1278-8#

  5. Seasonal Prediction of Regional Surface Air Temperature and First-flowering Date in South Korea using Dynamical Downscaling

    Science.gov (United States)

    Ahn, J. B.; Hur, J.

    2015-12-01

    The seasonal prediction of both the surface air temperature and the first-flowering date (FFD) over South Korea are produced using dynamical downscaling (Hur and Ahn, 2015). Dynamical downscaling is performed using Weather Research and Forecast (WRF) v3.0 with the lateral forcing from hourly outputs of Pusan National University (PNU) coupled general circulation model (CGCM) v1.1. Gridded surface air temperature data with high spatial (3km) and temporal (daily) resolution are obtained using the physically-based dynamical models. To reduce systematic bias, simple statistical correction method is then applied to the model output. The FFDs of cherry, peach and pear in South Korea are predicted for the decade of 1999-2008 by applying the corrected daily temperature predictions to the phenological thermal-time model. The WRF v3.0 results reflect the detailed topographical effect, despite having cold and warm biases for warm and cold seasons, respectively. After applying the correction, the mean temperature for early spring (February to April) well represents the general pattern of observation, while preserving the advantages of dynamical downscaling. The FFD predictabilities for the three species of trees are evaluated in terms of qualitative, quantitative and categorical estimations. Although FFDs derived from the corrected WRF results well predict the spatial distribution and the variation of observation, the prediction performance has no statistical significance or appropriate predictability. The approach used in the study may be helpful in obtaining detailed and useful information about FFD and regional temperature by accounting for physically-based atmospheric dynamics, although the seasonal predictability of flowering phenology is not high enough. Acknowledgements This work was carried out with the support of the Rural Development Administration Cooperative Research Program for Agriculture Science and Technology Development under Grant Project No. PJ009953 and

  6. An improved model for soil surface temperature from air temperature in permafrost regions of Qinghai-Xizang (Tibet) Plateau of China

    Science.gov (United States)

    Hu, Guojie; Wu, Xiaodong; Zhao, Lin; Li, Ren; Wu, Tonghua; Xie, Changwei; Pang, Qiangqiang; Cheng, Guodong

    2016-06-01

    Soil temperature plays a key role in hydro-thermal processes in environments and is a critical variable linking surface structure to soil processes. There is a need for more accurate temperature simulation models, particularly in Qinghai-Xizang (Tibet) Plateau (QXP). In this study, a model was developed for the simulation of hourly soil surface temperatures with air temperatures. The model incorporated the thermal properties of the soil, vegetation cover, solar radiation, and water flux density and utilized field data collected from Qinghai-Xizang (Tibet) Plateau (QXP). The model was used to simulate the thermal regime at soil depths of 5 cm, 10 cm and 20 cm and results were compared with those from previous models and with experimental measurements of ground temperature at two different locations. The analysis showed that the newly developed model provided better estimates of observed field temperatures, with an average mean absolute error (MAE), root mean square error (RMSE), and the normalized standard error (NSEE) of 1.17 °C, 1.30 °C and 13.84 %, 0.41 °C, 0.49 °C and 5.45 %, 0.13 °C, 0.18 °C and 2.23 % at 5 cm, 10 cm and 20 cm depths, respectively. These findings provide a useful reference for simulating soil temperature and may be incorporated into other ecosystem models requiring soil temperature as an input variable for modeling permafrost changes under global warming.

  7. Influence of Surface Resistivity and Temperature on Variation with Time of Current Pulses in Air at Optimum Pressure

    Directory of Open Access Journals (Sweden)

    S.G. Pimpale

    1977-04-01

    Full Text Available The variation of discharge current pulses with the surface nature of electrodes has been investigated by producing discharge in the intense ionizing zone of two ozonizers (A&B containing pure, dry air at a pressure of 4 & 10mm of mercury respectively. The course of reaction in the tube A showed that the periodic rise and fall of discharge counts through a series of recurrences whose amplitude varied randomly. During this reaction, steady potential, temperature of the electrolytic bath, counting time and pulse height were kept fixed. The phenomenon obtained for both the tubes is produced within a critical range of conditions. The results have been interpreted on the basis of activated adsorption at a temperature of 90 degree and 100 degree Centigrade and discussed on the theoretical grounds of change of surface resistivity upon the glass walls. Use of different coatings on annular surface in the same system with appropriate levels of electrolytic solution for a definite value of height-pulses and temperature, etc. shows significant variations in the discharge counts.

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  9. Time scales of the European surface air temperature variability: The role of the 7-8 year cycle

    Science.gov (United States)

    Jajcay, Nikola; Hlinka, Jaroslav; Kravtsov, Sergey; Tsonis, Anastasios A.; Paluš, Milan

    2016-01-01

    Air temperature variability on different time scales exhibits recurring patterns and quasi-oscillatory phenomena. Climate oscillations with the period about 7-8 years have been observed in many instrumental records in Europe. Although these oscillations are weak if considering their amplitude, they might have nonnegligible influence on temperature variability on shorter time scales due to cross-scale interactions recently observed by Paluš (2014). In order to quantify the cross-scale influence, we propose a simple conditional mean approach which estimates the effect of the cycle with the period close to 8 years on the amplitude of the annual cycle in surface air temperature (SAT) in the range 0.7-1.4°C and the effect on the overall variability of the SAT anomalies (SATA) leads to the changes 1.5-1.7°C in the annual SATA means. The strongest effect in the winter SATA means reaches 4-5°C in central European station and reanalysis data.

  10. Relationships of surface air temperature anomalies over Europe to persistence of atmospheric circulation patterns conducive to heat waves

    Directory of Open Access Journals (Sweden)

    J. Kyselý

    2008-04-01

    Full Text Available Heat waves are among natural hazards with the most severe consequences for human society, including pronounced mortality impacts in mid-latitudes. Recent studies have hypothesized that the enhanced persistence of atmospheric circulation may affect surface climatic extremes, mainly the frequency and severity of heat waves. In this paper we examine relationships between the persistence of the Hess-Brezowsky circulation types conducive to summer heat waves and air temperature anomalies at stations over most of the European continent. We also evaluate differences between temperature anomalies during late and early stages of warm circulation types in all seasons. Results show that more persistent circulation patterns tend to enhance the severity of heat waves and support more pronounced temperature anomalies. Recent sharply rising trends in positive temperature extremes over Europe may be related to the greater persistence of the circulation types, and if similar changes towards enhanced persistence affect other mid-latitudinal regions, analogous consequences and implications for temperature extremes may be expected.

  11. Fast Air Temperature Sensors

    DEFF Research Database (Denmark)

    Hendricks, Elbert

    1998-01-01

    The note documents briefly work done on a newly developed sensor for making fast temperature measurements on the air flow in the intake ports of an SI engine and in the EGR input line. The work reviewed has been carried out in close cooperation with Civ. Ing. Michael Føns, the author (IAU......) and Spencer C. Sorenson (ET). The theory which decribes in detail the overall dynamic chracteristics of the sensor was developed at IAU, DTU....

  12. Multiproxy summer and winter surface air temperature field reconstructions for southern South America covering the past centuries

    Energy Technology Data Exchange (ETDEWEB)

    Neukom, R.; Grosjean, M.; Wanner, H. [University of Bern, Oeschger Centre for Climate Change Research (OCCR), Bern (Switzerland); University of Bern, Institute of Geography, Climatology and Meteorology, Bern (Switzerland); Luterbacher, J. [Justus Liebig University of Giessen, Department of Geography, Climatology, Climate Dynamics and Climate Change, Giessen (Germany); Villalba, R.; Morales, M.; Srur, A. [CONICET, Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales (IANIGLA), Mendoza (Argentina); Kuettel, M. [University of Bern, Oeschger Centre for Climate Change Research (OCCR), Bern (Switzerland); University of Bern, Institute of Geography, Climatology and Meteorology, Bern (Switzerland); University of Washington, Department of Earth and Space Sciences, Seattle (United States); Frank, D. [Swiss Federal Research Institute WSL, Birmensdorf (Switzerland); Jones, P.D. [University of East Anglia, Climatic Research Unit, School of Environmental Sciences, Norwich (United Kingdom); Aravena, J.-C. [Centro de Estudios Cuaternarios de Fuego Patagonia y Antartica (CEQUA), Punta Arenas (Chile); Black, D.E. [Stony Brook University, School of Marine and Atmospheric Sciences, Stony Brook (United States); Christie, D.A.; Urrutia, R. [Universidad Austral de Chile Valdivia, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); D' Arrigo, R. [Earth Institute at Columbia University, Tree-Ring Laboratory, Lamont-Doherty Earth Observatory, Palisades, NY (United States); Lara, A. [Universidad Austral de Chile Valdivia, Laboratorio de Dendrocronologia, Facultad de Ciencias Forestales y Recursos Naturales, Valdivia (Chile); Nucleo Cientifico Milenio FORECOS, Fundacion FORECOS, Valdivia (Chile); Soliz-Gamboa, C. [Utrecht Univ., Inst. of Environmental Biology, Utrecht (Netherlands); Gunten, L. von [Univ. of Bern (Switzerland); Univ. of Massachusetts, Climate System Research Center, Amherst (United States)

    2011-07-15

    We statistically reconstruct austral summer (winter) surface air temperature fields back to ad 900 (1706) using 22 (20) annually resolved predictors from natural and human archives from southern South America (SSA). This represents the first regional-scale climate field reconstruction for parts of the Southern Hemisphere at this high temporal resolution. We apply three different reconstruction techniques: multivariate principal component regression, composite plus scaling, and regularized expectation maximization. There is generally good agreement between the results of the three methods on interannual and decadal timescales. The field reconstructions allow us to describe differences and similarities in the temperature evolution of different sub-regions of SSA. The reconstructed SSA mean summer temperatures between 900 and 1350 are mostly above the 1901-1995 climatology. After 1350, we reconstruct a sharp transition to colder conditions, which last until approximately 1700. The summers in the eighteenth century are relatively warm with a subsequent cold relapse peaking around 1850. In the twentieth century, summer temperatures reach conditions similar to earlier warm periods. The winter temperatures in the eighteenth and nineteenth centuries were mostly below the twentieth century average. The uncertainties of our reconstructions are generally largest in the eastern lowlands of SSA, where the coverage with proxy data is poorest. Verifications with independent summer temperature proxies and instrumental measurements suggest that the interannual and multi-decadal variations of SSA temperatures are well captured by our reconstructions. This new dataset can be used for data/model comparison and data assimilation as well as for detection and attribution studies at sub-continental scales. (orig.)

  13. Citywide Impacts of Cool Roof and Rooftop Solar Photovoltaic Deployment on Near-Surface Air Temperature and Cooling Energy Demand

    Science.gov (United States)

    Salamanca, F.; Georgescu, M.; Mahalov, A.; Moustaoui, M.; Martilli, A.

    2016-04-01

    Assessment of mitigation strategies that combat global warming, urban heat islands (UHIs), and urban energy demand can be crucial for urban planners and energy providers, especially for hot, semi-arid urban environments where summertime cooling demands are excessive. Within this context, summertime regional impacts of cool roof and rooftop solar photovoltaic deployment on near-surface air temperature and cooling energy demand are examined for the two major USA cities of Arizona: Phoenix and Tucson. A detailed physics-based parametrization of solar photovoltaic panels is developed and implemented in a multilayer building energy model that is fully coupled to the Weather Research and Forecasting mesoscale numerical model. We conduct a suite of sensitivity experiments (with different coverage rates of cool roof and rooftop solar photovoltaic deployment) for a 10-day clear-sky extreme heat period over the Phoenix and Tucson metropolitan areas at high spatial resolution (1-km horizontal grid spacing). Results show that deployment of cool roofs and rooftop solar photovoltaic panels reduce near-surface air temperature across the diurnal cycle and decrease daily citywide cooling energy demand. During the day, cool roofs are more effective at cooling than rooftop solar photovoltaic systems, but during the night, solar panels are more efficient at reducing the UHI effect. For the maximum coverage rate deployment, cool roofs reduced daily citywide cooling energy demand by 13-14 %, while rooftop solar photovoltaic panels by 8-11 % (without considering the additional savings derived from their electricity production). The results presented here demonstrate that deployment of both roofing technologies have multiple benefits for the urban environment, while solar photovoltaic panels add additional value because they reduce the dependence on fossil fuel consumption for electricity generation.

  14. Practical applications of the remote sensing-based two-source algorithm for mapping surface energy fluxes without in-situ air temperature observations

    Science.gov (United States)

    The two-source energy balance (TSEB) model uses remotely sensed maps of land-surface temperature (LST) along with local air temperature estimates at a nominal blending height to model heat and water fluxes across a landscape, partitioned between dual sources of canopy and soil. For operational imple...

  15. Unforced surface air temperature anomalies and their opposite relationship with the TOA energy imbalance at local and global scales

    Science.gov (United States)

    Brown, P. T.; Li, W.; Jiang, J. H.; Su, H.

    2015-12-01

    Unforced global mean surface air temperature (Tglobal) is stable in the long-term primarily because warm Tglobal anomalies are associated with enhanced outgoing longwave radiation to space and thus a negative global radiative energy imbalance (Nglobal, positive downward) at the top of the atmosphere (TOA). However, it is shown here that at the local spatial scale, warm unforced Tlocal anomalies tend to be associated with anomalously positive Nlocal imbalances over most of the surface of the planet. It is revealed that this occurs mainly because warm Tlocal anomalies are accompanied by anomalously low surface albedo near sea ice margins and over high altitudes, anomalously low cloud albedo over much of the mid/low-latitudes and an anomalously large water-vapor greenhouse effect over the deep tropical ocean. During warm Tglobal years, the largest negative Nlocal anomalies primarily occur over regions of cool or near-neutral Tlocal anomalies. These results help explain how TOA energy imbalances can act to damp unforced Tglobal anomalies while simultaneously amplifying unforced Tlocal anomalies.

  16. Decadal co-variability of the summer surface air temperature and soil moisture in China under global warming

    Institute of Scientific and Technical Information of China (English)

    SU MingFeng; WANG HuiJun

    2007-01-01

    The self-calibrating Palmer Drought Severity Index (PDSI) is calculated using newly updated ground observations of monthly surface air temperature (SAT) and precipitation in China. The co-variabilities of PDSI and SAT are examined for summer for the period 1961-2004. The results show that there exist decadal climate co-variabilities and strong nonlinear interactions between SAT and soil moisture in many regions of China. Some of the co-variabilities can be linked to global warming. In summer, significant decadal co-variabilities from cool-wet to warm-dry conditions are found in the east region of Northwest China, North China, and Northeast China. An important finding is that in the west region of Northwest China and Southeast China, pronounced decadal co-variabilities take place from warm-dry to cool-wet conditions. Because significant warming was observed over most areas of the global land surface during the past 20-30 years, the shift to cool-wet conditions is a unique phenomenon which may deserve much scientific attention. The nonlinear interactions between SAT and soil moisture may partly account for the observed decadal co-variabilities. It is shown that anomalies of SAT will greatly affect the climatic co-variabilities, and changes of SAT may bring notable influence on the PDSI in China. These results provide observational evidence for increasing risks of decadal drought and wetness as anthropogenic global warming progresses.

  17. A STUDY ON VARIABILITY OF SEA SURFACE TEMPERATURE IN TROPICAL PACIFIC, INDIAN OCEAN AND RELATED AIR CIRCULATION

    Institute of Scientific and Technical Information of China (English)

    Cui Mao-chang; Qiao Fang-li; Mo Jun

    2003-01-01

    Canonical Correlation Analysis (CCA) was adopted in the present paper to study the of Sea Surface Temperature (SST) in the tropical Pacific, Indian Ocean and related air circulation.The results show that on the seasonal time scale, E1 Nio events can be divided into two types: the east one and the middle one.For the middle type the SST variations appear contrarily in the tropical Pacific and Indian Ocean, and the anomalous SST decreases in the east but increases in the northwest and south-middle of the tropical Indian Ocean, specially in the east of Madagascar Island.And vice versa.On annual time scale, when the Asian continent high gets stronger and the deepened Aleutian low shifts southeastward, both of them trigger an onset of the E1 Nio events.Contrarily, the La Nia events take place.On decadal time scale, there are two basic modes of air-sea system over the tropical Pacific and Indian Ocean.Firstly, when the Asian continent high gets stronger and deepened Aleutian low shifts southeastward, the anomalous SST increases in the middle and east of the proical Pacific, extending to the subtropical regions, and so in most of the tropical Indian Ocean, specially in the northeast of Madagascar Island and nearby.And vice versa.Secondly, when the Asian continent high gets stronger in the north and the Aleutian low decreases fixedly or even disappears, the anomalous SST decreases slightly in middle of the tropical Pacific and the temperate northern Pacific but increases weakly in other regions, the anomalous SST increases in the south but decreases in the north of the tropical Indian Ocean, and the SST increases more obviously in southeast of Madagascar Island.And vice versa.The linear trends of global warming seems to play a certain role for the E1 Nio onsets.

  18. Response of Simulated Surface Air Temperature to the Interannual Variability of Leaf Area Index in Eastern China

    Directory of Open Access Journals (Sweden)

    Xuezhen Zhang

    2013-01-01

    Full Text Available Using the coupled WRF-Noah model, we conducted two experiments to investigate impacts of the interannual variability of leaf area index (LAI on the surface air temperature (SAT in eastern China. The Moderate Resolution Imaging Spectroradiometer (MODIS observed dynamic LAI data from 2002 to 2009 were used in one modeling experiment, and the climatological seasonal cycle of the MODIS LAI was used in the other experiment. The results show that the use of dynamic LAI improves model performance. Compared with the use of climatological LAI, the use of dynamic LAI may reduce the warm (cool bias in the years with large positive (negative LAI anomalies. The reduction of the warm bias results from the modeled cooling effect of LAI increase through reducing canopy resistance, promoting transpiration, and decreasing sensible heat flux. Conversely, the reduction of cool bias is a result of the warming effect of negative anomaly of LAI. The use of dynamic LAI can improve model performance in summer and to a lesser extent, spring and autumn. Moreover, the dynamic LAI exerts a detectable influence on SAT in the WRF model when the LAI anomaly is at least 20% of the climatological LAI.

  19. Time Scales of the European Surface Air Temperature Variability: The Role of the 7-8 Year Cycle

    Czech Academy of Sciences Publication Activity Database

    Jajcay, Nikola; Hlinka, Jaroslav; Kravtsov, S.; Tsonis, A.A.; Paluš, Milan

    2016-01-01

    Roč. 43, č. 2 (2016), s. 902-909. ISSN 0094-8276 R&D Projects: GA MŠk LH14001 Institutional support: RVO:67985807 Keywords : 7-8 year cycle * air temperature variability * annual cycle amplitude * cross-scale interactions * seasonality * time scales Subject RIV: DG - Athmosphere Sciences, Meteorology

  20. Deterministic and Probabilistic Metrics of Surface Air Temperature and Precipitation in the MiKlip Decadal Prediction System

    Science.gov (United States)

    Kadow, Christopher; Illing, Sebastian; Kunst, Oliver; Pohlmann, Holger; Müller, Wolfgang; Cubasch, Ulrich

    2014-05-01

    Decadal forecasting of climate variability is a growing need for different parts of society, industry and economy. The German initiative MiKlip (www.fona-miklip.de) focuses on the ongoing processes of medium-term climate prediction. The scientific major project funded by the Federal Ministry of Education and Research in Germany (BMBF) develops a forecast system, that aims for reliable predictions on decadal timescales. Using a single earth system model from the Max-Planck institute (MPI-ESM) and moving from the uninitialized runs on to the first initialized 'Coupled Model Intercomparison Project Phase 5' (CMIP5) hindcast experiments identified possibilities and open scientific tasks. The MiKlip decadal prediction system was improved on different aspects through new initialization techniques and datasets of the ocean and atmosphere. To accompany and emphasize such an improvement of a forecast system, a standardized evaluation system designed by the MiKlip sub-project 'Integrated data and evaluation system for decadal scale prediction' (INTEGRATION) analyzes every step of its evolution. This study aims at combining deterministic and probabilistic skill scores of this prediction system from its unitialized state to anomaly and then full-field oceanic initialization. The improved forecast skill in these different decadal hindcast experiments of surface air temperature and precipitation in the Pacific region and the complex area of the North Atlantic illustrate potential sources of skill. A standardized evaluation leads prediction systems depending on development to find its way to produce reliable forecasts. Different aspects of these research dependencies, e.g. ensemble size, resolution, initializations, etc. will be discussed.

  1. The Influence of Stratospheric Sulphate Aerosol Deployment on the Surface Air Temperature and the Risk of an Abrupt Global Warming

    Directory of Open Access Journals (Sweden)

    Roland von Glasow

    2010-12-01

    Full Text Available We used the ‘Radiative-Convective Model of the Earth-atmosphere system’ (OGIM to investigate the cooling effects induced by sulphur injections into the stratosphere. The ensemble of numerical calculations was based on the A1B scenario from the IPCC Special Report on Emissions Scenarios (SRES. Several geoengineered scenarios were analysed, including the abrupt interruption of these injections in different scenarios and at different dates. We focused on the surface air temperature (SAT anomalies induced by stratospheric sulphate aerosol generated in order to compensate future warming. Results show that continuous deployment of sulphur into the stratosphere could induce a lasting decrease in SAT. Retaining a constant aerosol loading equivalent to 6 TgS would delay the expected global warming by 53 years. Keeping the SAT constant in a context of increasing greenhouse gases (GHGs means that the aerosol loading needs to be increased by 1.9% annually. This would offset the effect of increasing GHG under the A1B scenario. A major focus of this study was on the heating rates of SAT that would arise in different scenarios in case of an abrupt cessation of sulphur injections into the stratosphere. Our model results show that heating rates after geoengineering interruption would be 15–28 times higher than in a case without geoengineering, with likely important consequences for life on Earth. Larger initial sulphate loadings induced more intense warming rates when the geoengineering was stopped at the same time. This implies that, if sulphate loading was increased to maintain constant SAT in the light of increasing GHG concentrations, the later the geoengineering interruption was to occur, the higher the heating rates would be. Consequently, geoengineering techniques like this should only be regarded as last-resort measures and require intense further research should they ever become necessary.

  2. Links between atmospheric circulation and surface air temperature in climate models in control climate and future scenarios

    Czech Academy of Sciences Publication Activity Database

    Plavcová, Eva; Kyselý, Jan

    Bern: Swiss Climate Research, 2011, s. 84-85. [International NCCR Climate Summer School "Climate Change, Extremes and Ecosystem Services" /10./. Grindelwald (CH), 04.09.2001-09.09.2011] R&D Projects: GA ČR GAP209/10/2265 Institutional research plan: CEZ:AV0Z30420517 Keywords : regional climate models * air temperature * atmospheric circulation * future climate change scenarios Subject RIV: DG - Athmosphere Sciences, Meteorology

  3. XPS Study of Chemical Changes on the La/Ce Treated Surface of A361 Aluminium Alloy Exposed to Air at Temperatures up to 500∘C

    OpenAIRE

    Matykina, E.; R. Arrabal; Merino, M. C.; S. Feliú; Pardo, A.

    2009-01-01

    The chemical changes that take place on the rare earth treated surface of the A361 aluminium alloy exposed to air at temperatures between 100 and 500∘C have been examined using X-ray photoelectron spectroscopy (XPS). The most notable features discussed in this work are the disappearance of Mg and Si signals at the tested temperatures and disappearance of the Ce signal at temperatures of 400–500∘C. The biphasic microstructure of the A361 alloy, constituted by close to 12 wt% Si and the Al matr...

  4. Air temperature thresholds to evaluate snow melting at the surface of Alpine glaciers by T-index models: the case study of Forni Glacier (Italy)

    Science.gov (United States)

    Senese, A.; Maugeri, M.; Vuillermoz, E.; Smiraglia, C.; Diolaiuti, G.

    2014-03-01

    The glacier melt conditions (i.e.: null surface temperature and positive energy budget) can be assessed by analyzing meteorological and energy data acquired by a supraglacial Automatic Weather Station (AWS). In the case this latter is not present the assessment of actual melting conditions and the evaluation of the melt amount is difficult and simple methods based on T-index (or degree days) models are generally applied. These models require the choice of a correct temperature threshold. In fact, melt does not necessarily occur at daily air temperatures higher than 273.15 K. In this paper, to detect the most indicative threshold witnessing melt conditions in the April-June period, we have analyzed air temperature data recorded from 2006 to 2012 by a supraglacial AWS set up at 2631 m a.s.l. on the ablation tongue of the Forni Glacier (Italian Alps), and by a weather station located outside the studied glacier (at Bormio, a village at 1225 m a.s.l.). Moreover we have evaluated the glacier energy budget and the Snow Water Equivalent (SWE) values during this time-frame. Then the snow ablation amount was estimated both from the surface energy balance (from supraglacial AWS data) and from T-index method (from Bormio data, applying the mean tropospheric lapse rate and varying the air temperature threshold) and the results were compared. We found that the mean tropospheric lapse rate permits a good and reliable reconstruction of glacier air temperatures and the major uncertainty in the computation of snow melt is driven by the choice of an appropriate temperature threshold. From our study using a 5.0 K lower threshold value (with respect to the largely applied 273.15 K) permits the most reliable reconstruction of glacier melt.

  5. A study on the direct effect of anthropogenic aerosols on near surface air temperature over Southeastern Europe during summer 2000 based on regional climate modeling

    Directory of Open Access Journals (Sweden)

    P. Zanis

    2009-10-01

    Full Text Available In the present work it is investigated the direct shortwave effect of anthropogenic aerosols on the near surface temperature over Southeastern Europe and the atmospheric circulation during summer 2000. In summer 2000, a severe heat-wave and droughts affected many countries in the Balkans. The study is based on two yearly simulations with and without the aerosol feedback of the regional climate model RegCM3 coupled with a simplified aerosol model. The surface radiative forcing associated with the anthropogenic aerosols is negative throughout the European domain with the more negative values in Central and Central-eastern Europe. A basic pattern of the aerosol induced changes in air temperature at the lower troposphere is a decrease over Southeastern Europe and the Balkan Peninsula (up to about 1.2°C thus weakening the pattern of the climatic temperature anomalies of summer 2000. The aerosol induced changes in air temperature from the lower troposphere to upper troposphere are not correlated with the respective pattern of the surface radiative forcing implying the complexity of the mechanisms linking the aerosol radiative forcing with the induced atmospheric changes through dynamical feedbacks of aerosols on atmospheric circulation. Investigation of the aerosol induced changes in the circulation indicates a southward shift of the subtropical jet stream playing a dominant role for the decrease in near surface air temperature over Southeastern Europe and the Balkan Peninsula. The southward shift of the jet exit region over the Balkan Peninsula causes a relative increase of the upward motion at the northern flank of the jet exit region, a relative increase of clouds, less solar radiation absorbed at the surface and hence relative cooler air temperatures in the lower troposphere between 45° N and 50° N. The southward extension of the lower troposphere aerosol induced negative temperature changes in the latitudinal band 35° N–45° N over the

  6. An Analysis of Simulated and Observed Global Mean Near-Surface Air Temperature Anomalies from 1979 to 1999: Trends and Attribution of Causes

    Science.gov (United States)

    MacKay, R. M.; Ko, M. K. W.

    2001-01-01

    The 1979 - 1999 response of the climate system to variations in solar spectral irradiance is estimated by comparing the global averaged surface temperature anomalies simulated by a 2D (two dimensional) energy balance climate model to observed temperature anomalies. We perform a multiple regression of southern oscillation index and the individual model responses to solar irradiance variations, stratospheric and tropospheric aerosol loading, stratospheric ozone trends, and greenhouse gases onto each of five near-surface temperature anomaly data sets. We estimate the observed difference in global mean near surface air temperature attributable to the solar irradiance difference between solar maximum and solar minimum to be between 0.06 and 0.11 K, and that 1.1 - 3.8% of the total variance in monthly mean near-surface air temperature data is attributable to nations in solar spectral irradiance. For the five temperature data sets used in our analysis, the trends in raw monthly mean temperature anomaly data have a large range, spanning a factor of 3 from 0.06 to 0.17 K/decade. However. our analysis suggests that trends in monthly temperature anomalies attributable to the combination of greenhouse gas, stratospheric ozone, and tropospheric sulfate aerosol variations are much more consistent among data sets, ranging from 0.16 to 0.24 K/decade. Our model results suggest that roughly half of the warming from greenhouse gases is cancelled by the cooling from changes in stratospheric ozone. Tropospheric sulfate aerosol loading in the present day atmospheric contributes significantly to the net radiative forcing of the present day climate system. However, because the change in magnitude and latitudinal distribution of tropospheric sulfate aerosol has been small over the past 20 years, the change in the direct radiative forcing attributable to changes in aerosol loading over this time is also small.

  7. Causality of global warming seen from observations: a scale analysis of driving force of the surface air temperature time series in the Northern Hemisphere

    Science.gov (United States)

    Yang, Peicai; Wang, Geli; Zhang, Feng; Zhou, Xiuji

    2016-05-01

    By using the slow feature analysis, we reconstructed the driving force for an observed monthly surface air temperature anomaly time series in the northern hemisphere. Wavelet transformation technique was then used to analyze the scale structure of the derived driving force and its causal relationship with global warming. Results showed that the driving force for the analyzed temperature climate system included two independent degrees of freedom which respectively represented the effects of 22-year solar cycle and Atlantic Multidecadal Oscillation on the climate. More importantly, the driving force is modulated in amplitude by signals with much longer time periods. The modulation controls the energy input to the climate system and its effect on the global warming is decisive. In addition, through analyzing phase transitions from zero to extremes of the modulating signals, we provide a projection for the future trend of the surface air temperature. In specific, in the next 45-65 years, the driving force will continue to rise which will drive the air temperature even warmer. This is a long term natural trend determined by the modulating amplitude signals, but not directly related to human activity.

  8. A relationship between regional and global GCM surface air temperature changes and its application to an integrated model of climate change

    International Nuclear Information System (INIS)

    This study outlines the advantages of combining the Integrated Model to Assess the Greenhouse affect (IMAGE, an integrated quick turnaround, global model of climate change) with a spatially detailed General Circulation Model (GCM), in this case developed at the Max Planck Institute for Meteorology (MPI) in Hamburg. The outcome is a modified IMAGE model that simulates the MPI GCM projections of annual surface air temperature change globally and regionally. IMAGE thus provides policy analysts with integrated and regional information about global warming for a great range of policy-dependent greenhouse gas emission or concentration scenarios, while preserving its quick turnaround time. With the help of IMAGE various regional temperature response simulations have been produced. None of these simulations has yet been performed by any GCM. The simulations reflect the uncertainty range of a future warming. In this study the authors deal only with a simplified subsystem of such an integrated model of climate change, which begins with policy options, neglects the societal component in the greenhouse gas accounting tool, and ends with temperature change as the only output of the climate model. The model the authors employ is the Integrated Model to Assess the Greenhouse Effect (IMAGE, version 1.0), which was developed by the Netherlands National Institute of Public Health and Environmental Protection (RIVM). IMAGE is a scientifically based, parameterized simulation policy model designed to calculate the historical and future effects of greenhouse gases on global surface and surface air temperatures and sea-level rise

  9. Nowcasting daily minimum air and grass temperature

    Science.gov (United States)

    Savage, M. J.

    2016-02-01

    Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient ( b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

  10. Error estimations of dry deposition velocities of air pollutants using bulk sea surface temperature under common assumptions

    Science.gov (United States)

    Lan, Yung-Yao; Tsuang, Ben-Jei; Keenlyside, Noel; Wang, Shu-Lun; Arthur Chen, Chen-Tung; Wang, Bin-Jye; Liu, Tsun-Hsien

    2010-07-01

    It is well known that skin sea surface temperature (SSST) is different from bulk sea surface temperature (BSST) by a few tenths of a degree Celsius. However, the extent of the error associated with dry deposition (or uptake) estimation by using BSST is not well known. This study tries to conduct such an evaluation using the on-board observation data over the South China Sea in the summers of 2004 and 2006. It was found that when a warm layer occurred, the deposition velocities using BSST were underestimated within the range of 0.8-4.3%, and the absorbed sea surface heat flux was overestimated by 21 W m -2. In contrast, under cool skin only conditions, the deposition velocities using BSST were overestimated within the range of 0.5-2.0%, varying with pollutants and the absorbed sea surface heat flux was underestimated also by 21 W m -2. Scale analysis shows that for a slightly soluble gas (e.g., NO 2, NO and CO), the error in the solubility estimation using BSST is the major source of the error in dry deposition estimation. For a highly soluble gas (e.g., SO 2), the error in the estimation of turbulent heat fluxes and, consequently, aerodynamic resistance and gas-phase film resistance using BSST is the major source of the total error. In contrast, for a medium soluble gas (e.g., O 3 and CO 2) both the errors from the estimations of the solubility and aerodynamic resistance are important. In addition, deposition estimations using various assumptions are discussed. The largest uncertainty is from the parameterizations for chemical enhancement factors. Other important areas of uncertainty include: (1) various parameterizations for gas-transfer velocity; (2) neutral-atmosphere assumption; (3) using BSST as SST, and (4) constant pH value assumption.

  11. Sensitivity of Global Sea-Air CO2 Flux to Gas Transfer Algorithms, Climatological Wind Speeds, and Variability of Sea Surface Temperature and Salinity

    Science.gov (United States)

    McClain, Charles R.; Signorini, Sergio

    2002-01-01

    Sensitivity analyses of sea-air CO2 flux to gas transfer algorithms, climatological wind speeds, sea surface temperatures (SST) and salinity (SSS) were conducted for the global oceans and selected regional domains. Large uncertainties in the global sea-air flux estimates are identified due to different gas transfer algorithms, global climatological wind speeds, and seasonal SST and SSS data. The global sea-air flux ranges from -0.57 to -2.27 Gt/yr, depending on the combination of gas transfer algorithms and global climatological wind speeds used. Different combinations of SST and SSS global fields resulted in changes as large as 35% on the oceans global sea-air flux. An error as small as plus or minus 0.2 in SSS translates into a plus or minus 43% deviation on the mean global CO2 flux. This result emphasizes the need for highly accurate satellite SSS observations for the development of remote sensing sea-air flux algorithms.

  12. Characteristics of surface-wave plasma with air-simulated N2-O2 gas mixture for low-temperature sterilization

    International Nuclear Information System (INIS)

    Sterilization experiments using low-pressure air discharge plasma sustained by the 2.45 GHz surface-wave have been carried out. Geobacillus stearothermoplilus spores having a population of 3.0 x 106 were sterilized for only 3 min using air-simulated N2-O2 mixture gas discharge plasma, faster than the cases of pure O2 or pure N2 discharge plasmas. From the SEM analysis of plasma-irradiated spores and optical emission spectroscopy measurements of the plasmas, it has been found that the possible sterilization mechanisms of air-simulated plasma are the chemical etching effect due to the oxygen radicals and UV emission from the N2 molecules and NO radicals in the wavelength range 200-400 nm. Experiment suggested that UV emission in the wavelength range less than 200 nm might not be significant in the sterilization. The UV intensity at 237.0 nm originated from the NO γ system (A 2Σ+ → X 2Π) in N2-O2 plasma as a function of the O2 percentage added to N2-O2 mixture gas has been investigated. It achieved its maximum value when the O2 percentage was roughly 10-20%. This result suggests that air can be used as a discharge gas for sterilization, and indeed we have confirmed a rapid sterilization with the actual air discharge at a sample temperature of less than 65 deg. C

  13. Dynamic air layer on textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev

    2013-09-03

    We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured superhydrophobic surfaces in air-supersaturated water by a natural gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can be sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growth. Both the observed growth dynamics of such plastrons and millimeter-sized air bubbles seeded on the hydrophilic surface under identical air-supersaturated solution conditions are consistent with the predictions of a well-mixed gas transport model. © 2013 American Chemical Society.

  14. Air/delta/sea surface temperature, pressure, and other data from MISS GAIL in a world-wide distribution from 21 October 1957 to 18 April 1961 (NODC Accession 0000366)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Air/delta/sea surface temperature, pressure, and other data were collected from the MISS GAIL in a world-wide distribution from October 21, 1957 to April 18, 1961....

  15. Behavior of a thermoelectric power generation device based on solar irradiation and the earth’s surface-air temperature difference

    International Nuclear Information System (INIS)

    Highlights: • A technical solution to the power supply of wireless sensor networks is presented. • The low voltage produced by TEG is boosted from less than 1 V to more than 4 V. • An output current and voltage of TEG device is acquired as 21.47 mA and 221 mV. • The device successfully provides output power 4.7 mW in no electricity conditions. • The thermo-economic value of TEG device is demonstrated. - Abstract: Motivated by the limited power supply of wireless sensors used to monitor the natural environment, for example, in forests, this study presents a technical solution by recycling solar irradiation heat using thermoelectric generators. Based on solar irradiation and the earth’s surface-air temperature difference, a new type of thermoelectric power generation device has been devised, the distinguishing features of which include the application of an all-glass heat-tube-type vacuum solar heat collection pipe to absorb and transfer solar energy without a water medium and the use of a thin heat dissipation tube to cool the earth surface air temperature. The effects of key parameters such as solar illumination, air temperature, load resistance, the proportional coefficient, output power and power generation efficiency for thermoelectric energy conversion are analyzed. The results of realistic outdoor experiments show that under a state of regular illumination at 3.75 × 104 lx, using one TEG module, the thermoelectric device is able to boost the voltage obtained from the natural solar irradiation from 221 mV to 4.41 V, with an output power of 4.7 mW. This means that the electrical energy generated can provide the power supply for low power consumption components, such as low power wireless sensors, ZigBee modules and other low power loads

  16. Variation of Surface Air Temperature in Relation to El Nino and Cataclysmic Volcanic Eruptions, 1796-1882

    Science.gov (United States)

    Wilson, Robert M.

    1999-01-01

    During the contemporaneous interval of 1796-1882 a number of significant decreases in temperature are found in the records of Central England and Northern Ireland. These decreases appear to be related to the occurrences of El Nino and/or cataclysmic volcanic eruptions. For example, a composite of residual temperatures of the Central England dataset, centering temperatures on the yearly onsets of 20 El Nino of moderate to stronger strength, shows that, on average, the change in temperature varied by about +/- 0.3 C from normal being warmer during the boreal fall-winter leading up to the El Nino year and cooler during the spring-summer of the El Nino year. Also, the influence of El Nino on Central England temperatures appears to last about 1-2 years. Similarly, a composite of residual temperatures of the Central England dataset, centering temperatures on the month of eruption for 26 cataclysmic volcanic eruptions, shows that, on average, the change in temperature decreased by about 0.1 - 0.2 C, typically, 1-2 years after the eruption, although for specific events, like Tambora, the decrease was considerably greater. Additionally, tropical eruptions appear to produce greater changes in temperature than extratropical eruptions, and eruptions occurring in boreal spring-summer appear to produce greater changes in temperature than those occurring in fall-winter.

  17. Surface Temperature Data Analysis

    Science.gov (United States)

    Hansen, James; Ruedy, Reto

    2012-01-01

    Small global mean temperature changes may have significant to disastrous consequences for the Earth's climate if they persist for an extended period. Obtaining global means from local weather reports is hampered by the uneven spatial distribution of the reliably reporting weather stations. Methods had to be developed that minimize as far as possible the impact of that situation. This software is a method of combining temperature data of individual stations to obtain a global mean trend, overcoming/estimating the uncertainty introduced by the spatial and temporal gaps in the available data. Useful estimates were obtained by the introduction of a special grid, subdividing the Earth's surface into 8,000 equal-area boxes, using the existing data to create virtual stations at the center of each of these boxes, and combining temperature anomalies (after assessing the radius of high correlation) rather than temperatures.

  18. Evaluation of Surface Air Temperature Change over China and the Globe during the Twentieth Century in IAP AGCM4.0

    Institute of Scientific and Technical Information of China (English)

    DONG Xiao; XUE Feng; ZHANG He; ZENG Qing-Cun

    2012-01-01

    Based on time series and linear trend analysis, the authors evaluated the performance of the fourth gen- eration atmospheric general circulation model developed at the Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP AGCM4.0), in simulating surface air temperature (SAT) during the twentieth century over China and the globe. The numerical experiment is con- ducted by driving the model with the observed sea surface temperature and sea ice. It is shown that IAP AGCM4.0 can simulate the warming trend of the global SAT, with the major wanning regions in the high latitudes of the Northern Hemisphere and the mid-latitudes of the South- ern Hemisphere. While the simulated trend over the whole globe is close to the observation, the model trader- estimates the observed trend over the continents. More- over, the model simulates the spatial distribution of SAT in China, with a bias of approximately -2℃ in eastern China, but with a more serious bias in western China. Compared with the global mean, however, the correlation coefficient between the simulation and observation in China is significantly lower, indicating that there is large uncertainty in simulating regional climate change.

  19. Percolation Phase Transition of Surface Air Temperature Networks under Attacks of El Niño/La Niña

    Science.gov (United States)

    Lu, Zhenghui; Yuan, Naiming; Fu, Zuntao

    2016-05-01

    In this study, sea surface air temperature over the Pacific is constructed as a network, and the influences of sea surface temperature anomaly in the tropical central eastern Pacific (El Niño/La Niña) are regarded as a kind of natural attack on the network. The results show that El Niño/La Niña leads an abrupt percolation phase transition on the climate networks from stable to unstable or metastable phase state, corresponding to the fact that the climate condition changes from normal to abnormal significantly during El Niño/La Niña. By simulating three different forms of attacks on an idealized network, including Most connected Attack (MA), Localized Attack (LA) and Random Attack (RA), we found that both MA and LA lead to stepwise phase transitions, while RA leads to a second-order phase transition. It is found that most attacks due to El Niño/La Niña are close to the combination of MA and LA, and a percolation critical threshold Pc can be estimated to determine whether the percolation phase transition happens. Therefore, the findings in this study may renew our understandings of the influence of El Niño/La Niña on climate, and further help us in better predicting the subsequent events triggered by El Niño/La Niña.

  20. Evaluation of surface air temperature and urban effects in Japan simulated by non-hydrostatic regional climate model

    Science.gov (United States)

    Murata, A.; Sasaki, H.; Hanafusa, M.; Kurihara, K.

    2012-12-01

    We evaluated the performance of a well-developed nonhydrostatic regional climate model (NHRCM) with a spatial resolution of 5 km with respect to temperature in the present-day climate of Japan, and estimated urban heat island (UHI) intensity by comparing the model results and observations. The magnitudes of root mean square error (RMSE) and systematic error (bias) for the annual average of daily mean (Ta), maximum (Tx), and minimum (Tn) temperatures are within 1.5 K, demonstrating that the temperatures of the present-day climate are reproduced well by NHRCM. These small errors indicate that temperature variability produced by local-scale phenomena is represented well by the model with a higher spatial resolution. It is also found that the magnitudes of RMSE and bias in the annually-average Tx are relatively large compared with those in Ta and Tn. The horizontal distributions of the error, defined as the difference between simulated and observed temperatures (simulated minus observed), illustrate negative errors in the annually-averaged Tn in three major metropolitan areas: Tokyo, Osaka, and Nagoya. These negative errors in urban areas affect the cold bias in the annually-averaged Tx. The relation between the underestimation of temperature and degree of urbanization is therefore examined quantitatively using National Land Numerical Information provided by the Ministry of Land, Infrastructure, Transport, and Tourism. The annually-averaged Ta, Tx, and Tn are all underestimated in the areas where the degree of urbanization is relatively high. The underestimations in these areas are attributed to the treatment of urban areas in NHRCM, where the effects of urbanization, such as waste heat and artificial structures, are not included. In contrast, in rural areas, the simulated Tx is underestimated and Tn is overestimated although the errors in Ta are small. This indicates that the simulated diurnal temperature range is underestimated. The reason for the relatively large

  1. Projections of high resolution climate changes for South Korea using multiple-regional climate models based on four RCP scenarios. Part 1: Surface air temperature

    Science.gov (United States)

    Suh, Myoung-Seok; Oh, Seok-Geun; Lee, Young-Suk; Ahn, Joong-Bae; Cha, Dong-Hyun; Lee, Dong-Kyou; Hong, Song-You; Min, Seung-Ki; Park, Seong-Chan; Kang, Hyun-Suk

    2016-05-01

    We projected surface air temperature changes over South Korea during the mid (2026-2050) and late (2076-2100) 21st century against the current climate (1981-2005) using the simulation results from five regional climate models (RCMs) driven by Hadley Centre Global Environmental Model, version 2, coupled with the Atmosphere- Ocean (HadGEM2-AO), and two ensemble methods (equal weighted averaging, weighted averaging based on Taylor's skill score) under four Representative Concentration Pathways (RCP) scenarios. In general, the five RCM ensembles captured the spatial and seasonal variations, and probability distribution of temperature over South Korea reasonably compared to observation. They particularly showed a good performance in simulating annual temperature range compared to HadGEM2-AO. In future simulation, the temperature over South Korea will increase significantly for all scenarios and seasons. Stronger warming trends are projected in the late 21st century than in the mid-21st century, in particular under RCP8.5. The five RCM ensembles projected that temperature changes for the mid/late 21st century relative to the current climate are +1.54oC/+1.92oC for RCP2.6, +1.68oC/+2.91oC for RCP4.5, +1.17oC/+3.11oC for RCP6.0, and +1.75oC/+4.73oC for RCP8.5. Compared to the temperature projection of HadGEM2-AO, the five RCM ensembles projected smaller increases in temperature for all RCP scenarios and seasons. The inter-RCM spread is proportional to the simulation period (i.e., larger in the late-21st than mid-21st century) and significantly greater (about four times) in winter than summer for all RCP scenarios. Therefore, the modeled predictions of temperature increases during the late 21st century, particularly for winter temperatures, should be used with caution.

  2. Projections of high resolution climate changes for South Korea using multiple-regional climate models based on four RCP scenarios. Part 1: surface air temperature

    Science.gov (United States)

    Suh, Myoung-Seok; Oh, Seok-Geun; Lee, Young-Suk; Ahn, Joong-Bae; Cha, Dong-Hyun; Lee, Dong-Kyou; Hong, Song-You; Min, Seung-Ki; Park, Seong-Chan; Kang, Hyun-Suk

    2016-05-01

    We projected surface air temperature changes over South Korea during the mid (2026-2050) and late (2076-2100) 21st century against the current climate (1981-2005) using the simulation results from five regional climate models (RCMs) driven by Hadley Centre Global Environmental Model, version 2, coupled with the Atmosphere- Ocean (HadGEM2-AO), and two ensemble methods (equal weighted averaging, weighted averaging based on Taylor's skill score) under four Representative Concentration Pathways (RCP) scenarios. In general, the five RCM ensembles captured the spatial and seasonal variations, and probability distribution of temperature over South Korea reasonably compared to observation. They particularly showed a good performance in simulating annual temperature range compared to HadGEM2-AO. In future simulation, the temperature over South Korea will increase significantly for all scenarios and seasons. Stronger warming trends are projected in the late 21st century than in the mid-21st century, in particular under RCP8.5. The five RCM ensembles projected that temperature changes for the mid/late 21st century relative to the current climate are +1.54°C/+1.92°C for RCP2.6, +1.68°C/+2.91°C for RCP4.5, +1.17°C/+3.11°C for RCP6.0, and +1.75°C/+4.73°C for RCP8.5. Compared to the temperature projection of HadGEM2-AO, the five RCM ensembles projected smaller increases in temperature for all RCP scenarios and seasons. The inter-RCM spread is proportional to the simulation period (i.e., larger in the late-21st than mid-21st century) and significantly greater (about four times) in winter than summer for all RCP scenarios. Therefore, the modeled predictions of temperature increases during the late 21st century, particularly for winter temperatures, should be used with caution.

  3. MODIS Global Sea Surface Temperature

    Science.gov (United States)

    2002-01-01

    Every day the Moderate-resolution Imaging Spectroradiometer (MODIS) measures sea surface temperature over the entire globe with high accuracy. This false-color image shows a one-month composite for May 2001. Red and yellow indicates warmer temperatures, green is an intermediate value, while blues and then purples are progressively colder values. The new MODIS sea surface temperature product will be particularly useful in studies of temperature anomalies, such as El Nino, as well as research into how air-sea interactions drive changes in weather and climate patterns. In the high resolution image, notice the amazing detail in some of the regional current patterns. For instance, notice the cold water currents that move from Antarctica northward along South America's west coast. These cold, deep waters upwell along an equatorial swath around and to the west of the Galapagos Islands. Note the warm, wide currents of the Gulf Stream moving up the United States' east coast, carrying Caribbean warmth toward Newfoundland and across the Atlantic toward Western Europe. Note the warm tongue of water extending from Africa's east coast to well south of the Cape of Good Hope. MODIS was launched in December 1999 aboard NASA's Terra satellite. For more details on this and other MODIS data products, please see NASA Unveils Spectacular Suite of New Global Data Products from MODIS. Image courtesy MODIS Ocean Group, NASA GSFC, and the University of Miami

  4. The role of sea–land air thermal difference, shape of the coastline and sea surface temperature in the nocturnal offshore convection

    Directory of Open Access Journals (Sweden)

    Jordi Mazón

    2013-01-01

    Full Text Available Nocturnal precipitation cells and lines occur near the coastline in the whole Mediterranean basin in all seasons. The precipitation events are mainly located in areas where coastal mountain ranges and rivers enhance convergence though the interaction of nocturnal mesoscale and local flows (land breeze, katabatic and drainages winds with prevailing synoptic wind or with other mesoscale and local flows. The methodology used here to study this phenomenon consists of three stages. First, the Tropical Rainfall Measuring Mission (TRMM radar satellite database is used to detect nocturnal precipitation near the coastline, from 18 to 09 UTC. An event is included in the study if the 3 hours accumulated precipitation detected by TRMM is stationary near the coast, or has moved slightly onshore or offshore, and has lasted no more than six consecutive hours. Second, the NCEP reanalysis database is used to describe the synoptic conditions and to discard precipitation associated with synoptic events (large low pressure areas, dynamic polar fronts, or troughs, for example. In the final step by using the version 3 of the Weather Research Forecast model, we simulate and analyse some of the selected events to determine the role of the land–sea temperature differences, the curvature of the coastline and the sea surface temperature.The simulations confirm that the nocturnal precipitation studied in the Mediterranean basin near the coastline is formed from the interaction between relatively warm and wet sea-air with the cold air mass from drainage winds, as well as from the convergence of several drainage winds offshore. The mechanism is the same that is used to explain nocturnal precipitation in tropical areas.

  5. Analysis of the total solar irradiance composite and their contribution to global mean air surface temperature rise

    Science.gov (United States)

    Scafetta, N.

    2008-12-01

    Herein I discuss and propose updated satellite composites of the total solar irradiance covering the period 1978-2008. The composites are compiled from measurements made with the three ACRIM experiments. Measurements from the NIMBUS7/ERB, the ERBS/ERBE satellite experiments and a total solar irradiance proxy reconstruction are used to fill the gap from June 1989 to October 1991 between ACRIM1 and ACRIM2 experiments. The result of the analysis does suggests that the total solar irradiance did increase from 1980 to 2002. The climate implications of the alternative satellite composites are discussed by using a phenomenological climate model which depends on two characteristics time response at tau1 =0.4 year and tau2=8-12 years, as determined phenomenologically [Scafetta, JGR 2008]. Reconstructions of total solar irradiance signature on climate during the last four centuries are discussed. The solar variability appears to have significantly contributed to climate change during the last four centuries, including the last century. Indirectly, the model suggests that the preindustrial climate experienced a large variability which is incompatible with an Hockey Stick temperature graph.

  6. GODAE, SFCOBS - Surface Temperature Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GODAE, SFCOBS - Surface Temperature Observations: Ship, fixed/drifting buoy, and CMAN in-situ surface temperature. Global Telecommunication System (GTS) Data. The...

  7. Recent warming in Greenland in a long-term instrumental (1881–2012) climatic context: I. Evaluation of surface air temperature records

    International Nuclear Information System (INIS)

    We present an updated analysis of monthly means of daily mean, minimum and maximum surface air temperature (SAT) data from Greenland coastal weather stations and from a long-running site on the Greenland ice sheet, and analyse these data for evidence of climate change, especially focusing on the last 20 years but using the whole periods of available records (some since 1873). We demonstrate very strong recent warming along the west coast of Greenland, especially during winter (locally >10 °C since 1991), and rather weaker warming on the east Greenland coast, which is influenced by different oceanographic/sea-ice and meteorological synoptic forcing conditions to the rest of Greenland. Coastal Greenland seasonal mean SAT trends were generally 2–6 °C, strongest in winter (5.7 °C) and least in summer and autumn (both 2.2 °C), during 1981–2011/12. Since 2001 Greenland mean coastal SAT increased significantly by 2.9 °C in winter and 0.8 °C in summer but decreased insignificantly by 1.1 °C in autumn and 0.2 °C in spring, during a period when there was little net change (≤ ± 0.1 °C) in northern hemisphere temperatures. SAT means for the latest 2001–11/12 decade were significantly in excess of those for peak decadal periods during the Early Twentieth Century Warm Period only in summer and winter, and not significantly greater in spring and autumn. Summer SAT increases in southern Greenland for the last 20 years were generally greater for maximum than minimum temperatures. By contrast, in winter, the recent warming was greater for minimum than maximum temperatures. The greatest SAT changes in all seasons are seen on Greenland’s west coast. SAT changes on the ice sheet and a key marginal glacier closely followed nearby coastal temperatures over the last 20 years. (letter)

  8. Prospects of using Bayesian model averaging for the calibration of one-month forecasts of surface air temperature over South Korea

    Science.gov (United States)

    Kim, Chansoo; Suh, Myoung-Seok

    2013-05-01

    In this study, we investigated the prospect of calibrating probabilistic forecasts of surface air temperature (SAT) over South Korea by using Bayesian model averaging (BMA). We used 63 months of simulation results from four regional climate models (RCMs) with two boundary conditions (NCEP-DOE and ERA-interim) over the CORDEX East Asia. Rank histograms and residual quantile-quantile (R-Q-Q) plots showed that the simulation skills of the RCMs differ according to season and geographic location, but the RCMs show a systematic cold bias irrespective of season and geographic location. As a result, the BMA weights are clearly dependent on geographic location, season, and correlations among the models. The one-month equal weighted ensemble (EWE) outputs for the 59 stations over South Korea were calibrated using the BMA method for 48 monthly time periods based on BMA weights obtained from the previous 15 months of training data. The predictive density function was calibrated using BMA and the individual forecasts were weighted according to their performance. The raw ensemble forecasts were assessed using the flatness of the rank histogram and the R-Q-Q plot. The results showed that BMA improves the calibration of the EWE and the other weighted ensemble forecasts irrespective of season, simulation skill of the RCM, and geographic location. In addition, deterministic-style BMA forecasts usually perform better than the deterministic forecast of the single best member.

  9. The international surface temperature initiative

    Science.gov (United States)

    Thorne, P. W.; Lawrimore, J. H.; Willett, K. M.; Allan, R.; Chandler, R. E.; Mhanda, A.; de Podesta, M.; Possolo, A.; Revadekar, J.; Rusticucci, M.; Stott, P. A.; Strouse, G. F.; Trewin, B.; Wang, X. L.; Yatagai, A.; Merchant, C.; Merlone, A.; Peterson, T. C.; Scott, E. M.

    2013-09-01

    The aim of International Surface Temperature Initiative is to create an end-to-end process for analysis of air temperature data taken over the land surface of the Earth. The foundation of any analysis is the source data. Land surface air temperature records have traditionally been stored in local, organizational, national and international holdings, some of which have been available digitally but many of which are available solely on paper or as imaged files. Further, economic and geopolitical realities have often precluded open sharing of these data. The necessary first step therefore is to collate readily available holdings and augment these over time either through gaining access to previously unavailable digital data or through data rescue and digitization activities. Next, it must be recognized that these historical measurements were made primarily in support of real-time weather applications where timeliness and coverage are key. At almost every long-term station it is virtually certain that changes in instrumentation, siting or observing practices have occurred. Because none of the historical measures were made in a metrologically traceable manner there is no unambiguous way to retrieve the true climate evolution from the heterogeneous raw data holdings. Therefore it is desirable for multiple independent groups to produce adjusted data sets (so-called homogenized data) to adequately understand the data characteristics and estimate uncertainties. Then it is necessary to benchmark the performance of the contributed algorithms (equivalent to metrological software validation) through development of realistic benchmark datasets. In support of this, a series of successive benchmarking and assessment cycles are envisaged, allowing continual improvement while avoiding over-tuning of algorithms. Finally, a portal is proposed giving access to related data-products, utilizing the assessment results to provide guidance to end-users on which product is the most suited to

  10. Guess-Work and Reasonings on Centennial Evolution of Surface Air Temperature in Russia: Is it Possible to Build Bifurcation Diagrams Based on Extra-Short Local Observations?

    Science.gov (United States)

    Kolokolov, Yury; Monovskaya, Anna

    2015-06-01

    Since the bifurcation analysis remains the basic tool to inquire into nonlinear system dynamics, then, theoretically, the bifurcation analysis should be widely used to estimate the evolution of the climate dynamics at a certain geographic point over the last centenary. But it does not occur in practice. A viewpoint how to estimate such evolution is proposed and discussed in the paper. The viewpoint can be briefly formulated as the following: the extra-short timescale, plus the novel conceptual model, plus the modified bifurcation diagrams. So, first, only the data of instrumental measurements (hereafter observations) are used to build the bifurcation diagram, correspondingly, the timescale is restricted by the maximal duration of the reliable observations. In particular, 130-years time series of the land surface air temperature in Russia are analyzed in the paper. Second, the conceptual model (HDS-model) to describe the annual warming-cooling cycle dynamics similar to the dynamics of the hysteresis regulator with double synchronization (HDS-regulator) is introduced. Correspondingly, the local climate dynamics is considered as the dynamics of the system with a variable structure. The main advantage of HDS-model is the possibility to describe quite simply the rich variety of the observable temperature evolution based on the known nonlinear phenomena by the combinations of C-bifurcations (or, in other words, border-collision bifurcations) between three conjugate periodical processes with the same period but different orders of structural changes. Then HDS-hypothesis on the climate dynamics is proposed, where the local temperature evolution is considered under the competition between both amplitude and time quantizations within the Sun-Earth-Moon system. Processing the observations follows the SUC-logic conceptions on the experimental bifurcation analysis that allows to untangle the intricate nonlinear nonstationary behavior of a local climate system by using both

  11. Predictability of the Indian Summer Monsoon onset through an analysis of variations in surface air temperature and relative humidity during the pre-monsoon season

    Science.gov (United States)

    Stolbova, V.; Surovyatkina, E.; Bookhagen, B.; Kurths, J.

    2014-12-01

    The prediction of the Indian Summer monsoon (ISM) onset is one of the vital questions for the Indian subcontinent, as well as for areas directly or indirectly affected by the ISM. In previous studies, the areas used for ISM-onset prediction were often too large (or too small), or did not include all necessary information for the ISM-onset forecasting. Here, we present recent findings that suggest that a climate network approach may help to provide better definitions for areas used for ISM-onset prediction and an overall better ISM-onset prediction. Our analysis focuses on the following domains: North West Pakistan (NP) and the Eastern Ghats (EG) as they have been identified to include important pre-monsoon information for predicting ISM onset dates. Specifically, we focus on the analysis of surface air temperature and relative humidity in both areas that allows us to derive temporal trends and to estimate the ISM onset. We propose an approach, which allows to determine ISM onset in advance in 67% of all considered years. Our proposed approach is less effective during the anomalous years, which are associated with weak/strong monsoons, e.g. El-Nino, La-Nina or positive Indian Ocean Dipole events. ISM onset is predicted for 23 out of 27 normal monsoon years (85%) during the past 6 decades. In addition, we show that time series analysis in both areas during the pre-monsoon period reveals indicators whether the forthcoming ISM will be normal or weaker/stronger.

  12. An examination of the relationship between the Southern Annular Mode and Antarctic surface air temperatures in the CMIP5 historical runs

    Science.gov (United States)

    Marshall, Gareth J.; Bracegirdle, Thomas J.

    2015-09-01

    Strong relationships exist between the Southern Annular Mode (SAM) and surface air temperature (SAT) across much of Antarctica. Changes in the SAM will have a profound influence on future Antarctic climate so it is important that the models used to predict climate change can accurately reproduce current SAM-SAT relationships. We analyse data from 50 Climate Model Intercomparison Project (CMIP) 5 models to assess how well they reproduce the observed mean and variability of annual and seasonal SAM-SAT relationships at six Antarctic stations. Overall, the models do better at reproducing these relationships when meridional flow has its largest influence on SAT, doing best (worst) in winter (autumn and summer). They are generally unable to replicate existing seasonal cycles in the strength of the SAM-SAT relationship and show much less spatial and especially temporal variability in the strength of these relationships than is observed. Using an estimate of intrinsic variability to quantify the skill of the CMIP5 models, their average ability to successfully replicate a seasonal SAM-SAT relationship at the six locations studied ranges from 16 % in autumn to 32 % in winter. The mean success rate of a single model across all four seasons is 24 %, ranging from 8 to 38 % (compared to a `perfect model' with 46 %). Analysing the different atmospheric circulation patterns associated with extreme SAM-SAT correlations in the models demonstrates the importance of correctly reproducing both the climatological mean and variability of the planetary longwaves at Southern Hemisphere high-latitudes (particularly wave-number 3), in order to accurately reproduce observed SAM-SAT relationships across Antarctica.

  13. Perceived air quality, thermal comfort, and SBS symptoms at low air temperature and increased radiant temperature

    DEFF Research Database (Denmark)

    Toftum, Jørn; Reimann, Gregers Peter; Foldbjerg, P.;

    2002-01-01

    This study investigated if low air temperature, which is known to improve the perception of air quality, also can reduce the intensity of some SBS symptoms. In a low-polluting office, human subjects were exposed to air at two temperatures 23 deg.C and 18 deg.C both with and without a pollution...... source present at the low temperature. To maintain overall thermal neutrality, the low air temperature was partly compensated for by individually controlled radiant heating, and partly by allowing subjects to modify clothing insulation. A reduction of the air temperature from 23 deg.C to 18 deg.......C suggested an improvement of the perceived air quality, while no systematic effect on symptom intensity was observed. The overall indoor environment was evaluated equally acceptable at both temperatures due to local thermal discomfort at the low air temperature....

  14. Precision temperature controlled filtered laminar air enclosure

    International Nuclear Information System (INIS)

    We demonstrate a novel temperature controlled filtered laminar air enclosure composed of primarily off-the-shelf components that can be applied to a broad class of systems to significantly enhance their performance. An air mixing method is employed to provide variable cooling of the incoming filtered air, providing a temperature stability of ± 0.02 °C within the enclosure. The method is inexpensive to implement, and is suitable for a wide range of temperature controlled enclosures, with dimensions in the approximate range from 1 m to 5 m, making it ideal for many scientific applications. (technical design note)

  15. NOAA NOS SOS, EXPERIMENTAL - Air Temperature

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have air temperature data. *These services are for testing and evaluation...

  16. Estimating the Mean Annual Surface Air Temperature at Armagh Observatory, Northern Ireland, and the Global Land-Ocean Temperature Index for Sunspot Cycle 24, the Current Ongoing Sunspot Cycle

    Science.gov (United States)

    Wilson, Robert M.

    2013-01-01

    surface air temperature (ASAT) and the Global Land-Ocean Temperature Index (GLOTI) in relation to SSN and the SC in order to determine their likely values during SC24. Hence, it may provide insight as to whether solar forcing of global temperature is now lessening as a contributor to global warming, thereby indicating a possible cooling in the near term immediate future that potentially could ameliorate the effect of increased anthropogenic warming.

  17. 中国东部冬季气温异常与海表温度异常的关系分析%Analysis of Relationship between Winter Air Temperature in Eastern China and Sea Surface Temperature Anomaly

    Institute of Scientific and Technical Information of China (English)

    陈少勇; 张燕霞; 夏权; 白登元; 张晓芬

    2009-01-01

    采用SVD、相关分析及EOF方法, 分析了中国东部冬季地面气温与北大西洋及北太平洋海温异常变化的关系.结果表明: (1)中国东部冬季气温变化的一致性较高;(2)冬季气温异常与前一年9月北大西洋海域关键区(16°~40°N, 60°~24°W)海温和当年2月西北太平洋关键区(20°~40°N, 124°E~180°)海温呈显著的正相关分布, 即前一年9月北大西洋和当年2月西北太平洋海温异常偏高(低), 东部冬季气温亦偏高(低), 即前一年9月北大西洋海温的异常是否为我国冬季气温的气候预测提供了一种前期信号;(3)关键区海温对中国东部冬季气温的影响存在区域差异.北大西洋前期海温与中国东部冬季气温有密切的关系, 而西北太平洋的海温主要影响长江流域及其以北的季风中部区;(4)海温影响气温的可能机理是西北太平洋海温异常升高, 使乌山脊减弱, 阿拉斯加脊减弱, 东亚大槽减弱向东移动, 纬向环流加强, 高纬度的冷空气不易南下, 导致我国东部大部分地区冬季气温偏暖, 反之亦然.在年代际尺度上, 纬向环流和东亚大槽对海温有显著的响应;但在年际变化方面, 东亚大槽对海温的响应不显著.%Using the SVD, correlation analysis and EOF method, the relationship between the winter air temperature and sea surface temperature anomaly change (SSTA) in eastern China are analyzed. The main results are as follows: (1)Winter temperature of eastern China changes in high uniformity; (2)Winter temperature of eastern China anomaly has obviously isotopic distribution with sea temperate in February of the same year over Northwest Pacific Ocean key area (20°~40°N, 124°E~180°) and in September of the last year over North Atlantic Ocean key area (16°~40°N, 60°~24°W), namely, when the sea temperature in September of the last year over North Atlantic Ocean and in February of the same year over Northwest Pacific

  18. Historical Evolution of Global and Regional Surface Air Temperature Simulated by FGOALS-s2 and FGOALS-g2:How Reliable Are the Model Results?

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tianjun; SONG Fengfei; CHEN Xiaolong

    2013-01-01

    In order to assess the performance of two versions of the IAP/LASG Flexible Global Ocean-Atmosphere-Land System (FGOALS) model,simulated changes in surface air temperature (SAT),from natural and anthropogenic forcings,were compared to observations for the period 1850-2005 at global,hemispheric,continental and regional scales.The global and hemispheric averages of SAT and their land and ocean components during 1850 2005 were well reproduced by FGOALS-g2,as evidenced by significant correlation coefficients and small RMSEs.The significant positive correlations were firstly determined by the warming trends,and secondly by interdecadal fluctuations.The abilities of the models to reproduce interdecadal SAT variations were demonstrated by both wavelet analysis and significant positive correlations for detrended data.The observed land-sea thermal contrast change was poorly simulated.The major weakness of FGOALS-s2 was an exaggerated warming response to anthropogenic forcing,with the simulation showing results that were far removed from observations prior to the 1950s.The observations featured warming trends (1906-2005)of 0.71,0.68 and 0.79℃ (100 yr) 1 for global,Northern and Southern Hemispheric averages,which were overestimated by FGOALS-s2 [1.42,1.52 and 1.13℃ (100 yr)-1] but underestimated by FGOALS-g2 [0.69,0.68 and 0.73℃ (100 yr)-1].The polar amplification of the warming trend was exaggerated in FGOALS-s2 but weakly reproduced in FGOALS-g2.The stronger response of FGOALS-s2 to anthropogenic forcing was caused by strong sea-ice albedo feedback and water vapor feedback.Examination of model results in 15 selected subcontinental-scale regions showed reasonable performance for FGOALS-g2 over most regions.However,the observed warming trends were overestimated by FGOALS-s2 in most regions.Over East Asia,the meridional gradient of the warming trend simulated by FGOALS-s2 (FGOALS-g2) was stronger (weaker)than observed.

  19. 江西省冬季气温异常与区域海温的关联%Relationship between Winter Air Temperature in Jiangxi and Regional Sea Surface Temperature

    Institute of Scientific and Technical Information of China (English)

    马锋敏; 章毅之; 何拥凤; 张超美; 唐传师

    2012-01-01

    Using the monthly temperature from 81 stations of Jiangxi and the sea surface temperature (SST) data from NOAA, the possible relation between winter (DJF) temperature anomalies in Jiangxi and Global SSTA is analyzed. The coupling relationship between the anomalous distribution in winter air temperature and the variations of SST is studied with the Singular Value Decomposition (SVD) analysis method. The interaction between key areas is also discussed with the lead-lag correlation analysis and SVD methods. The main results are as follows: (1) The winter air the temperature anomaly of Jiangxi had obviously identical distribution with concurrent SSTs over the Indian Ocean (10°S to 20°N, 54° to 90°E) and Northwest Pacific Ocean key area (20° to 40° N, 120 to 180° E), and the preceding August to September SSTs over the North Atlantic Ocean key area (24° to 44°N, 20° to 60°W) ; (2) The correlation between the warmer seawater and warmer winter in Jiangxi was better over the Northwest Pacific Ocean key area than that over the Indian Ocean, and the correlation between cooler seawater and cooler winter in Jiangxi was better over the Pacific Ocean than that over the Northwest Pacific Ocean. The SSTAs over the Indian Ocean and Northwest Pacific Ocean key areas can be used to correct the influence of the North Atlantic Ocean SSTA in winter air temperature prediction in Jiangxi.%利用1960-2010年江西省81个台站月平均气温观测资料和NOAA全球月平均海表温度资料(ERSST-V3),分析了江西省冬季气温异常与海温异常的相互联系,并运用超前-滞后相关分析和奇异值分解(SVD)方法初步探讨了关键区海温异常之间的相互作用.结果表明:①影响江西省冬季气温异常的海温关键区和关键时段分别为同期印度洋(10°S~20°N,54°~90°E)、同期西北太平洋(20°~40°N,120°~180°E)和前期8-9月北大西洋中部(24°~44°N,20°~60°W)海域;②西北太平洋关键区暖水年预

  20. Influence of the outlet air temperature on the thermohydraulic behaviour of air coolers

    Directory of Open Access Journals (Sweden)

    Đorđević Emila M.

    2003-01-01

    Full Text Available The determination of the optimal process conditions for the operation of air coolers demands a detailed analysis of their thermohydraulic behaviour on the one hand, and the estimation of the operating costs, on the other. One of the main parameters of the thermohydraulic behaviour of this type of equipment, is the outlet air temperature. The influence of the outlet air temperature on the performance of air coolers (heat transfer coefficient overall heat transfer coefficient, required surface area for heat transfer air-side pressure drop, fan power consumption and sound pressure level was investigated in this study. All the computations, using AirCooler software [1], were applied to cooling of the process fluid and the condensation of a multicomponent vapour mixture on two industrial devices of known geometries.

  1. Modeling monthly mean air temperature for Brazil

    Science.gov (United States)

    Alvares, Clayton Alcarde; Stape, José Luiz; Sentelhas, Paulo Cesar; de Moraes Gonçalves, José Leonardo

    2013-08-01

    Air temperature is one of the main weather variables influencing agriculture around the world. Its availability, however, is a concern, mainly in Brazil where the weather stations are more concentrated on the coastal regions of the country. Therefore, the present study had as an objective to develop models for estimating monthly and annual mean air temperature for the Brazilian territory using multiple regression and geographic information system techniques. Temperature data from 2,400 stations distributed across the Brazilian territory were used, 1,800 to develop the equations and 600 for validating them, as well as their geographical coordinates and altitude as independent variables for the models. A total of 39 models were developed, relating the dependent variables maximum, mean, and minimum air temperatures (monthly and annual) to the independent variables latitude, longitude, altitude, and their combinations. All regression models were statistically significant ( α ≤ 0.01). The monthly and annual temperature models presented determination coefficients between 0.54 and 0.96. We obtained an overall spatial correlation higher than 0.9 between the models proposed and the 16 major models already published for some Brazilian regions, considering a total of 3.67 × 108 pixels evaluated. Our national temperature models are recommended to predict air temperature in all Brazilian territories.

  2. Role of surface characteristics in urban meteorology and air quality

    Energy Technology Data Exchange (ETDEWEB)

    Sailor, D.J.

    1993-08-01

    Urbanization results in a landscape with significantly modified surface characteristics. The lower values of reflectivity to solar radiation, surface moisture availability, and vegetative cover, along with the higher values of anthropogenic heat release and surface roughness combine to result higher air temperatures in urban areas relative to their rural counterparts. Through their role in the surface energy balance and surface exchange processes, these surface characteristics are capable of modifying the local meteorology. The impacts on wind speeds, air temperatures, and mixing heights are of particular importance, as they have significant implications in terms of urban energy use and air quality. This research presents several major improvements to the meteorological modeling methodology for highly heterogeneous terrain. A land-use data-base is implemented to provide accurate specification of surface characteristic variability in simulations of the Los Angeles Basin. Several vegetation parameterizations are developed and implemented, and a method for including anthropogenic heat release into the model physics is presented. These modeling advancements are then used in a series of three-dimensional simulations which were developed to investigate the potential meteorological impact of several mitigation strategies. Results indicate that application of moderate tree-planting and urban-lightening programs in Los Angeles may produce summertime air temperature reductions on the order of 4{degree}C with a concomitant reduction in air pollution. The analysis also reveals several mechanisms whereby the application of these mitigation strategies may potentially increase pollutant concentrations. The pollution and energy use consequences are discussed in detail.

  3. Monitoring global monthly mean surface temperatures

    Science.gov (United States)

    Trenberth, Kevin E.; Christy, John R.; Hurrell, James W.

    1992-01-01

    The accuracy of the global surface air temperature (SST) estimates for a particular month over the past decade is assessed using all of the in situ observations available today. The sources of noise in the data, the numbers of observations, and the spatial coverage are appraised for the comparison with the climate signal, and different analyzed results are compared to determine their reproducibility. The data are further evaluated by comparing anomalies of near-global monthly mean surface temperatures with those of global satellite channel 2 microwave sounding unit temperatures for 144 months from 1979 to 1990. The results indicate that the inherent noise level in an SST observation is about 1.0 C, and this is compounded when the observation is made in regions of large temperature gradient.

  4. Simulations of the snow covered sea ice surface temperature and microwave effective temperature

    OpenAIRE

    Tonboe, Rasmus T.; Dybkjær, Gorm; Høyer, Jacob L.

    2011-01-01

    The snow surface on thick multiyear sea ice in winter is on average colder than the air because of the negative radiation balance. Beneath the snow surface there is a strong temperature gradient in winter with increasing temperatures towards the ice–water interface temperature at the freezing point around –1.8 °C. The sea ice surface temperature and the thermal microwave brightness temperature were simulated using a combination of thermodynamic and microwave emission models. The simulations i...

  5. Modeling of Air Temperature for Heat Exchange due to Vertical Turbulence and Horizontal Air Flow

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; MENG Qing-lin

    2009-01-01

    In order to calculate the air temperature of the near surface layer in urban environment,the Sur-face layer air was divided into several layers in the vertical direction,and some energy bakmce equations were de-veloped for each air layer,in which the heat exchange due to vertical turbulence and horizontal air flow was tak-en into account.Then,the vertical temperature distribution of the surface layer air was obtained through the coupled calculation using the energy balance equations of underlying surfaces and building walls.Moreover,the measured air temperatures in a small area (with a horizontal scale of less than 500 m) and a large area (with ahorizontal scale of more than 1000 m) in Guangzhou in summer were used to validate the proposed model.The calculated results agree well with the measured ones,with a maximum relative error of 4.18%.It is thus con-cluded that the proposed model is a high-accuracy method to theoretically analyze the urban heat island and the thermal environment.

  6. Response of global lightning activity to air temperature variation

    Institute of Scientific and Technical Information of China (English)

    MA Ming; TAO Shanchang; ZHU Baoyou; L(U) Weitao; TAN Yongbo

    2005-01-01

    It is an issue of great attention but yet not very clear whether lightning activities increase or decrease on a warmer world. Reeve et al. presented that lightning activities in global land and the Northern Hemisphere land have positive response to the increase of wet bulb temperature at 1000hPa. Is this positive response restricted only to wet bulb temperature or in land? What is the response of global lightning activities (in both land and ocean) to the global surface air temperature variation like? This paper, based on the 5-year or 8-year OTD/LIS satellite-based lightning detecting data and the NCEP reanalysis data, makes a reanalysis of the response of the global and regional lightning activities to temperature variations. The results show that on the interannual time scale the global total flash rate has positive response to the variation in global surface air temperature, with the sensitivity of 17±7% K-1. Also, the seasonal mean flash rate of continents all over the world and that of continents in the Northern Hemisphere have sensitive positive response to increase of global surface air temperature and wet bulb temperature, with the sensitivity of about 13±5% K-1, a bit lower than estimation of 40% K-1 in Reeve et al. However, the Southern Hemisphere and other areas like the tropics show no significant correlation.

  7. Global patterns in lake surface temperature trends

    Science.gov (United States)

    O'Reilly, C.; Sharma, S.; Gray, D.; Hampton, S. E.; Read, J. S.; Rowley, R.; McIntyre, P. B.; Lenters, J. D.; Schneider, P.; Hook, S. J.

    2014-12-01

    Temperature profoundly affects dynamics in the water bodieson which human societies depend worldwide. Even relatively small water temperature changes can alter lake thermal structure with implications for water level, nutrient cycling, ecosystem productivity, and food web dynamics. As air temperature increases with climate change and human land use transforms watersheds, rising water temperatures have been reported for individual lakes or regions, but a global synthesis is lacking; such a synthesis is foundational for understanding the state of freshwater resources. We investigated global patterns in lake surface water temperatures between 1985 and 2009 using in-situ and satellite data from 236 lakes. We demonstrate that lakes are warming significantly around the globe, at an average rate of 0.34 °C per decade. The breadth of lakes in this study allowed examination of the diversity of drivers across global lakes, and highlighted the importance of ice cover in determining the suite of morphological and climate drivers for lake temperature dynamics. These empirical results are consistent with modeled predictions of climate change, taking into account the extent to which water warming can be modulated by local environmental conditions and thus defy simple correlations with air temperature. The water temperature changes we report have fundamental importance for thermal structure and ecosystem functioning in global water resources; recognition of the extent to which lakes are currently in transition should have broad implications for regional and global models as well as for management.

  8. A physically based analytical spatial air temperature and humidity model

    Science.gov (United States)

    Yang, Yang; Endreny, Theodore A.; Nowak, David J.

    2013-09-01

    Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat storage based on semiempirical functions and generates spatially distributed estimates based on inputs of topography, land cover, and the weather data measured at a reference site. The model assumes that for all grids under the same mesoscale climate, grid air temperature and humidity are modified by local variation in absorbed solar radiation and the partitioning of sensible and latent heat. The model uses a reference grid site for time series meteorological data and the air temperature and humidity of any other grid can be obtained by solving the heat flux network equations. PASATH was coupled with the USDA iTree-Hydro water balance model to obtain evapotranspiration terms and run from 20 to 29 August 2010 at a 360 m by 360 m grid scale and hourly time step across a 285 km2 watershed including the urban area of Syracuse, NY. PASATH predictions were tested at nine urban weather stations representing variability in urban topography and land cover. The PASATH model predictive efficiency R2 ranged from 0.81 to 0.99 for air temperature and 0.77 to 0.97 for dew point temperature. PASATH is expected to have broad applications on environmental and ecological models.

  9. Surface Flux Modeling for Air Quality Applications

    OpenAIRE

    Limei Ran; Jonathan Pleim

    2011-01-01

    For many gasses and aerosols, dry deposition is an important sink of atmospheric mass. Dry deposition fluxes are also important sources of pollutants to terrestrial and aquatic ecosystems. The surface fluxes of some gases, such as ammonia, mercury, and certain volatile organic compounds, can be upward into the air as well as downward to the surface and therefore should be modeled as bi-directional fluxes. Model parameterizations of dry deposition in air quality models have been represented by...

  10. An RM-NN algorithm for retrieval of near-surface air temperature retrieval from MODIS data%用MODIS数据反演近地表空气温度的RM-NN算法

    Institute of Scientific and Technical Information of China (English)

    毛克彪; 马莹; 夏浪; 沈心一

    2013-01-01

    An algorithm for retrieving near-surface air temperature from MODIS 1B data based on radiance transfer model (RM) and a dynamic learning neural network (NN) was developed.The algorithm,called the RM-NN algorithm for short,uses the RM to simulate the radiance transfer from ground with different combinations of land surface temperature,near surface air temperature,emissivity and water vapor content.The dynamic learning neural network is used to estimate near surface air temperature.The analysis indicates that near surface air temperature can not be directly and accurately estimated from thermal remote sensing data.If the land surface temperature and emissivity and water vapor content are made as prior knowledge,the mean and the standard deviation of estimation error are about 0.8K and 0.9K.The mean and the standard deviation of estimation error are about 1.5K and 1.8K under considering the estimation error of land surface temperature and emissivity.Finally,the comparison of estimation results with ground measurement data at meteorological stations indicates that the RM-NN algorithm can be used to estimate near surface air temperature from MODIS 1B data.%基于辐射传输模型(RM)和动态学习神经网络(NN),成功进行了用MODIS数据反演近地表空气温度的研究,并给出了完成这种反演的RM-NN算法.该算法用RM来模拟不同地面辐射状况下(包括不同的地表温度、近地表空气温度、发射率和大气水汽含量)卫星高度获得的辐射强度数据集,用动态学习神经网络来进行反演计算.反演分析结果表明,近地表空气温度不能直接精确地用MODIS数据反演计算得到,如果能把地表温度和发射率以及大气水汽含量作为先验知识,则能够比较精确地反演近地表空气温度.模拟分析表明,平均误差和标准偏差分别大约是0.8K和0.9K,如果考虑地表温度和发射率的误差,平均误差和标准偏差分别为1.5K和1.8K.反演结果和地面气象站

  11. 40 CFR 91.309 - Engine intake air temperature measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  12. The surface temperature of Europa

    CERN Document Server

    Ashkenazy, Yosef

    2016-01-01

    Previous estimates of the surface temperature of Jupiter's moon, Europa, neglected the effect of the eccentricity of Jupiter's orbit around the Sun, the effect of the eclipse of Europa (i.e., the relative time that Europa is within the shadow of Jupiter), and the effect of Europa's internal heating. Here we estimate the surface temperature of Europa, when Europa's obliquity, eclipse and internal heating, as well as the eccentricity of Jupiter, are all taken into account. For a typical internal heating rate of 0.05 W/m$^2$ (corresponding to an ice thickness of about 10 kms), the equator, pole, and global mean surface temperatures are 101.7 K, 45.26 K, and 94.75 K, respectively. We found that the temperature at the high latitudes is significantly affected by the internal heating. We also studied the effect of the internal heating on the mean thickness of Europa's icy shell and conclude that the polar region temperature can be used to constrain the internal heating and the depth of the ice. Our approach and form...

  13. Improving Forecast Skill by Assimilation of AIRS Temperature Soundings

    Science.gov (United States)

    Susskind, Joel; Reale, Oreste

    2010-01-01

    AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The AIRS Version 5 retrieval algorithm, is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates delta T(p) for retrieved quantities and the use of these error estimates for Quality Control. We conducted a number of data assimilation experiments using the NASA GEOS-5 Data Assimilation System as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The model was run at a horizontal resolution of 0.5 deg. latitude X 0.67 deg longitude with 72 vertical levels. These experiments were run during four different seasons, each using a different year. The AIRS temperature profiles were presented to the GEOS-5 analysis as rawinsonde profiles, and the profile error estimates delta (p) were used as the uncertainty for each measurement in the data assimilation process. We compared forecasts analyses generated from the analyses done by assimilation of AIRS temperature profiles with three different sets of thresholds; Standard, Medium, and Tight. Assimilation of Quality Controlled AIRS temperature profiles significantly improve 5-7 day forecast skill compared to that obtained without the benefit of AIRS data in all of the cases studied. In addition, assimilation of Quality Controlled AIRS temperature soundings performs better than assimilation of AIRS observed radiances. Based on the experiments shown, Tight Quality Control of AIRS temperature profile performs best

  14. Surface Flux Modeling for Air Quality Applications

    Directory of Open Access Journals (Sweden)

    Limei Ran

    2011-08-01

    Full Text Available For many gasses and aerosols, dry deposition is an important sink of atmospheric mass. Dry deposition fluxes are also important sources of pollutants to terrestrial and aquatic ecosystems. The surface fluxes of some gases, such as ammonia, mercury, and certain volatile organic compounds, can be upward into the air as well as downward to the surface and therefore should be modeled as bi-directional fluxes. Model parameterizations of dry deposition in air quality models have been represented by simple electrical resistance analogs for almost 30 years. Uncertainties in surface flux modeling in global to mesoscale models are being slowly reduced as more field measurements provide constraints on parameterizations. However, at the same time, more chemical species are being added to surface flux models as air quality models are expanded to include more complex chemistry and are being applied to a wider array of environmental issues. Since surface flux measurements of many of these chemicals are still lacking, resistances are usually parameterized using simple scaling by water or lipid solubility and reactivity. Advances in recent years have included bi-directional flux algorithms that require a shift from pre-computation of deposition velocities to fully integrated surface flux calculations within air quality models. Improved modeling of the stomatal component of chemical surface fluxes has resulted from improved evapotranspiration modeling in land surface models and closer integration between meteorology and air quality models. Satellite-derived land use characterization and vegetation products and indices are improving model representation of spatial and temporal variations in surface flux processes. This review describes the current state of chemical dry deposition modeling, recent progress in bi-directional flux modeling, synergistic model development research with field measurements, and coupling with meteorological land surface models.

  15. Estimations of distribution and zoning for air temperature using satellite data over Liaoning province, China

    International Nuclear Information System (INIS)

    The distribution and zoning of air temperature over Liaoning Province, China were examined using the calculated values of air temperature derived from satellite data (GMS data) as well as from altitude data. The results are summarized as follows. At 02:00 LST the correlation coefficients for the air temperatures calculated from altitude compared with the observed air temperatures were the same as those of the air temperatures derived from GMS data. At 14:00 LST, however, the correlation coefficients for air temperatures calculated from altitude were less than those of the air temperatures derived from GMS data. This fact verifies that the distribution of air temperature in the day-time is affected by other factors than altitude. The distribution of air temperature in a cell of approximately 5'(latitude) x 7.5'(longitude) over Liaoning Province, china was estimated by using the regression equations between surface temperature derived from GMS and the observed air temperature. The distribution of air temperature was classified into 5 types, and the types are obtained at 14:00 LST are seasonal ones but the types at 02:00 LST are not related to season. Also, the regional classification for the air temperature was examined using this distribution of air temperature. This regional classification for the air temperature was similar to the published zoning of the agricultural climate. It became clear that the characteristic distribution of air temperature in a cell unit can be obtained by satellite data. And it is possible to define the zoning of air temperature for a cell unit by the accumulated analyses of satellite data over an extended period

  16. Air entrainment through free-surface cusps

    CERN Document Server

    Eggers, J

    2000-01-01

    In many industrial processes, such as pouring a liquid or coating a rotating cylinder, air bubbles are entrapped inside the liquid. We propose a novel mechanism for this phenomenon, based on the instability of cusp singularities that generically form on free surfaces. The air being drawn into the narrow space inside the cusp destroys its stationary shape when the walls of the cusp come too close. Instead, a sheet emanates from the cusp's tip, through which air is entrained. Our analytical theory of this instability is confirmed by experimental observation and quantitative comparison with numerical simulations of the flow equations.

  17. Monofractal nature of air temperature signals reveals their climate variability

    CERN Document Server

    Deliège, Adrien

    2014-01-01

    We use the discrete "wavelet transform microscope" to show that the surface air temperature signals of weather stations selected in Europe are monofractal. This study reveals that the information obtained in this way are richer than previous works studying long range correlations in meteorological stations. The approach presented here allows to bind the H\\"older exponents with the climate variability. We also establish that such a link does not exist with methods previously carried out.

  18. Temperature of rooftop photovoltaic modules: air gap effects

    Science.gov (United States)

    Shrestha, Bijay L.; Palomino, Ernie G.; TamizhMani, G.

    2009-08-01

    Performance of photovoltaic (PV) modules decreases as the operating temperature increases. This performance drop is typically higher for the crystalline silicon technologies (~0.5%/°C) as compared to thin film technologies (~0.2%/°C). The temperature of rooftop modules in hot climatic locations like Arizona could be as high as 95°C depending on the air gap between the modules and roof surface. There are several thermal models existing to predict the temperatures of open-rack PV modules but no comprehensive thermal models have been reported for the rooftop PV modules/arrays based on an extended field monitoring. The primary goal of this work is to quantitatively model the influence of air gap on the temperature of rooftop modules so that the system integrators could improve their designs to maximize the overall energy output (kWh/kW) of the rooftop PV systems. To predict the temperature of rooftop PV modules/arrays based on irradiance, ambient temperature and wind speed conditions, this paper presents five thermal models for each of the five air gaps (0, 1, 2, 3 & 4 inches) investigated in this work.

  19. Survival of Salmonella typhimurium ATCC 14028 on the surface of chicken legs or in mechanically deboned chicken meat gamma irradiated in air or vacuum at temperatures of -20 to +20 C

    International Nuclear Information System (INIS)

    Response-surface methodology was used to develop predictive equations for the response of Salmonella typhimurium ATCC 14028 on the surface of chicken legs or within mechanically deboned chicken meat (MDCM) to the effects of γ radiation doses of 0 to 3.60 kGy (100 krad = 1 kGy) at temperatures of -20 to +20 C in air or vacuum. A streptomycin-resistant mutant was used in these studies to allow accurate estimations of the surviving salmonellae in the presence of residual normal flora. This strain has been demonstrated to have no significant shift in its biological properties nor in its resistance to ionizing radiation. The response of S. typhimurium to gamma radiation was similar on both chicken legs and MDCM. The radiation was significantly more lethal to the bacterial cells at temperatures above freezing. The response-surface equations developed from the studies predict that the number of viable cells per gram of MDCM or per square centimeter of the surface of chicken legs would be reduced approximately 2.8 to 5.1 log units at 0 C by radiation doses within the range of 1.5 to 3.0 kGy. The results of the present studies are similar to those obtained previously with sterile mechanically deboned chicken meat

  20. Modeling air temperature through a combination of remote sensing and GIS data

    OpenAIRE

    Cristóbal Rosselló, Jordi; Ninyerola i Casals, Miquel; Pons, Xavier

    2008-01-01

    Air temperature is involved in many environmental processes such as actual and potential evapotranspiration, net radiation and species distribution. Ground meteorological stations provide important local data of air temperature, but a continuous surface for large and heterogeneous areas is also needed. In this paper we present a hybrid methodology between Remote Sensing and Geographical Information Systems to retrieve daily instantaneous, mean, maximum and minimum air temperatures (2002–2004)...

  1. CDC WONDER: Daily Air Temperatures and Heat Index

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Daily Air Temperature and Heat Index data available on CDC WONDER are county-level daily average air temperatures and heat index measures spanning the years...

  2. Quantifying the effect of plug-flat color on medium-surface temperatures

    International Nuclear Information System (INIS)

    Medium-surface temperature of black, gray, and white plug sheets was measured with thermocouples and an infrared camera. During the night, there were no medium-surface temperature differences between the plug flats; however, medium-surface temperature was 2 to 3 °C below air temperature. Medium-surface temperature increased as solar radiation (280 to 3000 nm) increased. About 80 W of solar radiation/m2 was incident on the plug-flat surface before medium-surface temperature equaled air temperature. Medium-surface temperature in the black, gray, and white flats was 6.3, 6.1, and 5.3 °C above air temperature, respectively, when 300 W of solar radiation/m2 (30% of the maximum solar radiation during the summer) was incident on the medium surface. Thus, incident solar radiation has a greater effect on medium surface temperature than plug-flat color. (author)

  3. 14 CFR 23.1157 - Carburetor air temperature controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  4. 40 CFR 89.325 - Engine intake air temperature measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  5. Estimating High Spatial Resolution Air Temperature for Regions with Limited in situ Data Using MODIS Products

    Directory of Open Access Journals (Sweden)

    Jinyoung Rhee

    2014-08-01

    Full Text Available The use of land surface temperature and vertical temperature profile data from Moderate Resolution Imaging Spectroradiometer (MODIS, to estimate high spatial resolution daily and monthly maximum and minimum 2 m above ground level (AGL air temperatures for regions with limited in situ data was investigated. A diurnal air temperature change model was proposed to consider the differences between the MODIS overpass times and the times of daily maximum and minimum temperatures, resulting in the improvements of the estimation in terms of error values, especially for minimum air temperature. Both land surface temperature and vertical temperature profile data produced relatively high coefficient of determination values and small Mean Absolute Error (MAE and Root Mean Square Error (RMSE values for air temperature estimation. The correction of the estimates using two gridded datasets, National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR reanalysis and Climate Research Unit (CRU, was performed and the errors were reduced, especially for maximum air temperature. The correction of daily and monthly air temperature estimates using the NCEP/NCAR reanalysis data, however, still produced relatively large error values compared to existing studies, while the correction of monthly air temperature estimates using the CRU data significantly reduced the errors; the MAE values for estimating monthly maximum air temperature range between 1.73 °C and 1.86 °C. Uncorrected land surface temperature generally performed better for estimating monthly minimum air temperature and the MAE values range from 1.18 °C to 1.89 °C. The suggested methodology on a monthly time scale may be applied in many data sparse areas to be used for regional environmental and agricultural studies that require high spatial resolution air temperature data.

  6. Spatial interpolation of monthly mean air temperature data for Latvia

    Science.gov (United States)

    Aniskevich, Svetlana

    2016-04-01

    Temperature data with high spatial resolution are essential for appropriate and qualitative local characteristics analysis. Nowadays the surface observation station network in Latvia consists of 22 stations recording daily air temperature, thus in order to analyze very specific and local features in the spatial distribution of temperature values in the whole Latvia, a high quality spatial interpolation method is required. Until now inverse distance weighted interpolation was used for the interpolation of air temperature data at the meteorological and climatological service of the Latvian Environment, Geology and Meteorology Centre, and no additional topographical information was taken into account. This method made it almost impossible to reasonably assess the actual temperature gradient and distribution between the observation points. During this project a new interpolation method was applied and tested, considering auxiliary explanatory parameters. In order to spatially interpolate monthly mean temperature values, kriging with external drift was used over a grid of 1 km resolution, which contains parameters such as 5 km mean elevation, continentality, distance from the Gulf of Riga and the Baltic Sea, biggest lakes and rivers, population density. As the most appropriate of these parameters, based on a complex situation analysis, mean elevation and continentality was chosen. In order to validate interpolation results, several statistical indicators of the differences between predicted values and the values actually observed were used. Overall, the introduced model visually and statistically outperforms the previous interpolation method and provides a meteorologically reasonable result, taking into account factors that influence the spatial distribution of the monthly mean temperature.

  7. Attribution of precipitation changes on ground-air temperature offset: Granger causality analysis

    Science.gov (United States)

    Cermak, Vladimir; Bodri, Louise

    2016-06-01

    This work examines the causal relationship between the value of the ground-air temperature offset and the precipitation changes for monitored 5-min data series together with their hourly and daily averages obtained at the Sporilov Geophysical Observatory (Prague). Shallow subsurface soil temperatures were monitored under four different land cover types (bare soil, sand, short-cut grass and asphalt). The ground surface temperature (GST) and surface air temperature (SAT) offset, ΔT(GST-SAT), is defined as the difference between the temperature measured at the depth of 2 cm below the surface and the air temperature measured at 5 cm above the surface. The results of the Granger causality test did not reveal any evidence of Granger causality for precipitation to ground-air temperature offsets on the daily scale of aggregation except for the asphalt pavement. On the contrary, a strong evidence of Granger causality for precipitation to the ground-air temperature offsets was found on the hourly scale of aggregation for all land cover types except for the sand surface cover. All results are sensitive to the lag choice of the autoregressive model. On the whole, obtained results contain valuable information on the delay time of ΔT(GST-SAT) caused by the rainfall events and confirmed the importance of using autoregressive models to understand the ground-air temperature relationship.

  8. Prediction of air temperature in the aircraft cabin under different operational conditions

    Directory of Open Access Journals (Sweden)

    Fišer J.

    2013-04-01

    Full Text Available This paper deals with the prediction of the air temperature in the aircraft cabin by means of Computational Fluid Dynamics. The simulations are performed on the CFD model which is based on geometry and cabin interior arrangement of the Flight Test Facility (FTF located at Fraunhofer IBP, Germany. The experimental test flights under three different cabin temperatures were done in FTF and the various data were gathered during these flights. Air temperature in the cabin was measured on probes located near feet, torso and head of each passenger and also surface temperature and air temperature distributed from inlets were measured. The data were firstly analysed in order to obtain boundary conditions for cabin surfaces and inlets. Then the results of air temperature from the simulations were compared with measured data. The suitability and accuracy of the CFD approach for temperature prediction is discussed.

  9. Prediction of air temperature in the aircraft cabin under different operational conditions

    Science.gov (United States)

    Volavý, F.; Fišer, J.; Nöske, I.

    2013-04-01

    This paper deals with the prediction of the air temperature in the aircraft cabin by means of Computational Fluid Dynamics. The simulations are performed on the CFD model which is based on geometry and cabin interior arrangement of the Flight Test Facility (FTF) located at Fraunhofer IBP, Germany. The experimental test flights under three different cabin temperatures were done in FTF and the various data were gathered during these flights. Air temperature in the cabin was measured on probes located near feet, torso and head of each passenger and also surface temperature and air temperature distributed from inlets were measured. The data were firstly analysed in order to obtain boundary conditions for cabin surfaces and inlets. Then the results of air temperature from the simulations were compared with measured data. The suitability and accuracy of the CFD approach for temperature prediction is discussed.

  10. 14 CFR 25.1157 - Carburetor air temperature controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  11. 14 CFR 29.1157 - Carburetor air temperature controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  12. Climate Prediction Center (CPC) U.S. Daily Minimum Air Temperature Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Observational reports of daily air temperature (1200 UTC to 1200 UTC) are made by members of the NWS Automated Surface Observing Systems (ASOS) network; NWS...

  13. Climate Prediction Center (CPC) U.S. Daily Maximum Air Temperature Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Observational reports of daily air temperature (1200 UTC to 1200 UTC) are made by members of the NWS Automated Surface Observing Systems (ASOS) network; NWS...

  14. How will land use affect air temperature in the surface boundary layer? Lessons learned from a comparative study on the energy balance of an oak savanna and annual grassland in California, USA

    OpenAIRE

    BALDOCCHI, DENNIS; Ma, Siyan

    2013-01-01

    We investigated the effect of land use on differences in air temperature. We based our analysis on a decade of weather and energy flux measurements, collected over two contrasting landscapes, an oak savanna and an annual grassland, growing under the same climate conditions. Over the decade, the daily-averaged, potential air temperature above the aerodynamically rougher and optically darker oak savanna was 0.5°C warmer than that above the aerodynamically smoother and optically brighter annual ...

  15. A High Temperature Regenerative Air Preheater for MHD Power Plants

    International Nuclear Information System (INIS)

    In order to attain sufficiently high flame temperatures so that combustion products can be used as a working fluid in an MHD generator, the combustion air must either be enriched with oxygen or preheated to relatively high temperatures. Ideally the regenerative preheat of the combustion air should be as high as possible. However, the air preheat temperature is limited by the availability and cost of high temperature materials, together with the feasibility of operating with seed impurities in the combustion products as well as of recovery of the seed added. The paper proposes the use of a high temperature heat exchanger system consisting of storage-type heaters with magnesium oxide as the bed matrix material. It contains a description of experimental apparatus to study such a system, and it presents experimental results. The system operates on the principle of successive heating and cooling of the bed matrix material by the hot combustion products and combustion air, respectively. The conditions governing condensation and evaporation of seed are described. During the heating of the bed, seed will at first condense when the gas is cooled below the dew point temperature for seed in the gas, but the condensed seed will evaporate again when the pebble surface temperature is brought above the equilibrium temperature for the vapour pressure of seed in the gas. With proper operation the temperature of the bed matrix material can be varied during normal cycling of the bed, such that the bed cleans itself of seed. The seed is then transported through the bed with the gas and recovered in electrostatic precipitators at the end of the system. Previous experiments with a pilot electrostatic precipitator have demonstrated that very high collection efficiencies can be obtained. The chemistry of seed and compatibility of using magnesium oxide as pebble and bed refractory material with alkali metal laden gas and condensed seed have been investigated. The experiments conducted have

  16. Air-sea interaction and spatial variability of the surface evaporation duct in a coastal environment

    Science.gov (United States)

    Brooks, Ian M.

    Aircraft observations are presented of the horizontal variability in the depth of the surface evaporation duct and the relationship with the mesoscale structure of air-sea interaction processes. The 2-dimensional fields of near-surface wind, stress, wind-stress curl, air and sea-surface temperature are measured directly for flow around a headland. The sea surface temperature field indicates cold upwelling driven by the wind-stress curl. Boundary-layer stability responds rapidly to the spatial changes in surface temperature. These changes result in modification of the evaporation duct, which decreases significantly in depth over the cooler upwelling water.

  17. Catalytic oxidation of tritium in air at ambient temperature

    International Nuclear Information System (INIS)

    Tritium/air oxidation kinetic data are derived from ambient-temperature measurements carried out with three precious-metal catalysts. Each catalyst consists of a high-surface-area substrate in pelletized form, onto which precious metal has been dispersed. The metal/substrate combinations investigated are platinum/alumina, palladium/kaolin, and palladium/zeolite. Electron-microprobe scans reveal that the dispersed metal is deposited in each case near the outer surface of the pellet, with metal concentration decreasing exponentially from the pellet surface. Kinetic oxidation measurements are made in a unique apparatus consisting of a large Lucite enclosure with an air atmosphere processed by a recirculating cleanup system. Dual-ionization chambers with an intermediate adsorption bed permit measurement of tritium gas and tritiated water vapor. Rate coefficients are determined from concentration decay following a spike injection of tritium into the enclosure. The catalytic reaction is first-order in tritium concentration in the range 10 to 105 μCi/m3. Addition of hydrogen carrier gas is unnecessary. Each of the dispersed-metal catalysts is extremely active in promoting tritium oxidation in comparison with self-catalyzed atmospheric conversion; equivalent first-order rate constants are higher by roughly 9 orders of magnitude. The platinum-based catalyst is more effective than the palladium catalysts on a surface-area basis by about a factor of 3. Catalytic activity for all three catalysts declines with time of exposure to air after activation, following a power-law decay with an exponent of -1/2. A model for optimization of the catalyst reactivation cycle is proposed, revealing that the optimum catalyst volume scales with flow rate to the 2/3 power. Ambient-temperature tritium oxidation is cost-effective for small- to intermediate-scale cleanup systems. A heated catalyst is desirable for large-scale systems

  18. Relationship between tree bark surface temperature and selected meteorological elements

    Science.gov (United States)

    Středa, Tomáš; Litschmann, Tomáš; Středová, Hana

    2015-12-01

    The results were obtained by measurements in 2014 and 2015 in an apple orchard in Starý Lískovec and Těšetice (South Moravia, Czech Republic, Central Europe) into fertile planting of apple trees. The results show that the bark surface temperature during the year slightly differs from the surrounding air temperature. In addition, it is in average a few tenths of a °C higher in the period before the onset of the vegetation and several tenths of a degree lower during vegetation. Causes of these differences appear to be associated with the flow of sap as well as with foliage. Although it can be reasonably assumed that the temperature of the bark surface on the south side will be significantly affected by the global radiation, our measurements did not demonstrate this dependency. It appears that the wind speed had significantly larger influence on the temperature differences in the non-vegetation period as at speeds over 3.5 m s-1, the drop of temperature is so significant that the bark surface is colder than the surrounding air. Comparison of the development of sums of daily and hourly effective temperatures above 10 °C has shown that where daily values do not show significant differences, hourly values differed so prominently that the calculated date of emergence of adult codling moth in the bark surface was approximately one week earlier than with the use of data for air temperatures.

  19. 40 CFR 90.309 - Engine intake air temperature measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  20. The influence of urban features on air temperature distribution.

    OpenAIRE

    M. Petralli; Massetti, L; S. Orlandini

    2008-01-01

    The knowledge of the influence of urban features on air temperature distribution in a city is very important, especially considering the population increase worldwide and the impact of urban climate on human health. The aim of this study is to investigate the distribution of air temperature in the city of Florence during the summer and to evaluate its relationship with building height, urban density and presence of trees. A significant positive relation between minimum air temperature and mea...

  1. EU Surface Temperature for All Corners of Earth - the EUSTACE project

    Science.gov (United States)

    Rayner, Nick; Auchmann, Renate; Bessembinder, Janette; Brönnimann, Stefan; Brugnara, Yuri; Carrea, Laura; Ghent, Darren; Good, Elizabeth; Herring, Katie; Høyer, Jacob; Kennedy, John; Klein Tank, Albert; Lindgren, Finn; Morice, Colin; Merchant, Chris; Remedios, John; Stephens, Ag; Tonboe, Rasmus

    2015-04-01

    Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, we must develop an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. These relationships can be derived either empirically or with the help of a physical model. Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals would be used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work would need to include partnerships with statisticians and computer scientists to enable the development of new "Big Data" analysis methods. To achieve this, the EUSTACE project will: • provide new, consistent, multi-component estimates of uncertainty in satellite retrievals of surface skin temperature; • identify inhomogeneities in daily surface air temperature measurement series from meteorological stations and correct for these over Europe; • estimate surface air temperature over all surfaces of Earth from surface skin temperature retrievals from satellites; • use new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of the information in data-rich eras. EUSTACE will undertake this work

  2. Analysis of Anomalously Low Surface Air Temperature in the Northern Hemisphere during 2009/2010 Winter%2009/2010年北半球冬季异常低温分析

    Institute of Scientific and Technical Information of China (English)

    孙诚; 李建平

    2012-01-01

    The anomalously low Surface Air Temperature (SAT) and the corresponding atmospheric circulation anomalies in the Northern Hemisphere during the winter (DJF) of 2009/2010 are investigated. Surface Air Temperature Anomalies (SATA) were zonally distributed with a "positive-negative-positive" pattern from tropical to polar region which was characterized by positive SATA in low latitudes, negative SATA in middle latitudes, and positive SAT A in high latitudes. The coldest SATA were located in Eurasia and eastern USA, and in some parts SATA exceeded -4 ℃. SAT in middle latitudes decreased by nearly 1 °C compared to the average of the last 15 years, and in Eurasia SAT even decreased by -8 ℃ The anomalous feathers of horizontal circulation was that, both sea level pressure and geopotential height fields exhibited positive anomalies in high latitudes and negative anomalies in low latitudes, associated with anticyelonic circulation anomalies in high latitudes and cyclonic circulation anomalies in middle latitude, and both high levels and low levels exhibited this feather. The anomalous feathers of zonally mean meridional circulation indicated that, Ferrel cell was weakened, with anomalous ascending motion in middle latitudes and anomalous descending motion in high latitudes, at the same time, atmosphere temperature of troposphere in middle latitudes was anomalously low and that in high latitudes was warmer, with a stronger jet in subtropics and a weaker jet in the polar region. Composite and correlation analysis of the Northern Hemisphere Annular Mode (NAM) and SATA shows that, during positive (negative) phase of NAM, there was a positive (negative) band in middle latitudes, and it was most significant in Eurasia and eastern USA, with nearly 2 °C warming (cooling) in some regions. Analysis of air temperature equation shows that meridional temperature advection anomalies associated with anomalous meridional wind play a very important role in the variability of local

  3. Modelling near subsurface temperature with mixed type boundary condition for transient air temperature and vertical groundwater flow

    Indian Academy of Sciences (India)

    Rajeev Ranjan Kumar; D V Ramana; R N Singh

    2012-10-01

    Near-subsurface temperatures have signatures of climate change. Thermal models of subsurface have been constructed by prescribing time dependent Dirichlet type boundary condition wherein the temperature at the soil surface is prescribed and depth distribution of temperature is obtained. In this formulation it is not possible to include the relationship between air temperatures and the temperature of soil surface. However, if one uses a Robin type boundary condition, a transfer coefficient relates the air and soil surface temperatures which helps to determine both the temperature at the surface and at depth given near surface air temperatures. This coefficient is a function of meteorological conditions and is readily available. We have developed such a thermal model of near subsurface region which includes both heat conduction and advection due to groundwater flows and have presented numerical results for changes in the temperature–depth profiles for different values of transfer coefficient and groundwater flux. There are significant changes in temperature and depth profiles due to changes in the transfer coefficient and groundwater flux. The analytical model will find applications in the interpretation of the borehole geothermal data to extract both climate and groundwater flow signals.

  4. Global Surface Temperature Change and Uncertainties Since 1861

    Science.gov (United States)

    Shen, Samuel S. P.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    The objective of this talk is to analyze the warming trend and its uncertainties of the global and hemi-spheric surface temperatures. By the method of statistical optimal averaging scheme, the land surface air temperature and sea surface temperature observational data are used to compute the spatial average annual mean surface air temperature. The optimal averaging method is derived from the minimization of the mean square error between the true and estimated averages and uses the empirical orthogonal functions. The method can accurately estimate the errors of the spatial average due to observational gaps and random measurement errors. In addition, quantified are three independent uncertainty factors: urbanization, change of the in situ observational practices and sea surface temperature data corrections. Based on these uncertainties, the best linear fit to annual global surface temperature gives an increase of 0.61 +/- 0.16 C between 1861 and 2000. This lecture will also touch the topics on the impact of global change on nature and environment. as well as the latest assessment methods for the attributions of global change.

  5. Startup of air-cooled condensers and dry cooling towers at low temperatures of the cooling air

    Science.gov (United States)

    Milman, O. O.; Ptakhin, A. V.; Kondratev, A. V.; Shifrin, B. A.; Yankov, G. G.

    2016-05-01

    The problems of startup and performance of air-cooled condensers (ACC) and dry cooling towers (DCT) at low cooling air temperatures are considered. Effects of the startup of the ACC at sub-zero temperatures are described. Different options of the ACC heating up are analyzed, and examples of existing technologies are presented (electric heating, heating up with hot air or steam, and internal and external heating). The use of additional heat exchanging sections, steam tracers, in the DCT design is described. The need for high power in cases of electric heating and heating up with hot air is noted. An experimental stand for research and testing of the ACC startup at low temperatures is described. The design of the three-pass ACC unit is given, and its advantages over classical single-pass design at low temperatures are listed. The formation of ice plugs inside the heat exchanging tubes during the start-up of ACC and DCT at low cooling air temperatures is analyzed. Experimental data on the effect of the steam flow rate, steam nozzle distance from the heat-exchange surface, and their orientation in space on the metal temperature were collected, and test results are analyzed. It is noted that the surface temperature at the end of the heat up is almost independent from its initial temperature. Recommendations for the safe start-up of ACCs and DCTs are given. The heating flow necessary to sufficiently heat up heat-exchange surfaces of ACCs and DCTs for the safe startup is estimated. The technology and the process of the heat up of the ACC with the heating steam external supply are described by the example of the startup of the full-scale section of the ACC at sub-zero temperatures of the cooling air, and the advantages of the proposed start-up technology are confirmed.

  6. Preliminary verification of instantaneous air temperature estimation for clear sky conditions based on SEBAL

    Science.gov (United States)

    Zhu, Shanyou; Zhou, Chuxuan; Zhang, Guixin; Zhang, Hailong; Hua, Junwei

    2016-03-01

    Spatially distributed near surface air temperature at the height of 2 m is an important input parameter for the land surface models. It is of great significance in both theoretical research and practical applications to retrieve instantaneous air temperature data from remote sensing observations. An approach based on Surface Energy Balance Algorithm for Land (SEBAL) to retrieve air temperature under clear sky conditions is presented. Taking the meteorological measurement data at one station as the reference and remotely sensed data as the model input, the research estimates the air temperature by using an iterative computation. The method was applied to the area of Jiangsu province for nine scenes by using MODIS data products, as well as part of Fujian province, China based on four scenes of Landsat 8 imagery. Comparing the air temperature estimated from the proposed method with that of the meteorological station measurement, results show that the root mean square error is 1.7 and 2.6 °C at 1000 and 30 m spatial resolution respectively. Sensitivity analysis of influencing factors reveals that land surface temperature is the most sensitive to the estimation precision. Research results indicate that the method has great potentiality to be used to estimate instantaneous air temperature distribution under clear sky conditions.

  7. The Climate Variabilities of Air Temperature Around the Korean Peninsula

    Institute of Scientific and Technical Information of China (English)

    Yong-Hoon YOUN

    2005-01-01

    In this study, changes in climatological conditions around the Korean Peninsula are estimated quantitatively using various types of high order statistical analyses. The temperature data collected from Incheon station have been analyzed for the assessment of the climate variation. According to our analysis,the climate changes observed over the Korean Peninsula for the last century are similar to the global observational data in many respects. First of all, the warming trend [+1.5℃ (100 yr)-1] and the overall evolving pattern throughout the century are quite similar to each other. The temperature change in the Korean Peninsula is about two to three times larger than that of the global scale which may partially be ascribed to the influence of urbanization at mid and high latitudes. In this work, a new Winter Monsoon Index (WMI) is suggested based on the European continental scale circulation index (EU1) pattern. Our WMI is defined as the normalized sea level pressure (SLP) difference in the winter period between the centers of the East Sea and west of Lake Baikal in Siberia, the two eastern centers of the EU1 action patterns. A strong similarity is found between the time series of the WMI and surface air temperature at Incheon. The WMI has decreased gradually since the 1920s but has shifted to a rapid increasing trend in the last two decades; it was in fact accompanied by a weakening of the Siberian High and a decreasing of the northerly during winter. Our findings of the close correlations between the surface air temperature at Incheon and the WMI strongly indicate that our newly suggested index is unique and can be used as an efficient tool to predict climate variability in Korea.

  8. Role of surface temperature in fluorocarbon plasma-surface interactions

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Caleb T.; Overzet, Lawrence J.; Goeckner, Matthew J. [Department of Electrical Engineering, University of Texas at Dallas, PO Box 830688, Richardson, TX 75083 (United States)

    2012-07-15

    This article examines plasma-surface reaction channels and the effect of surface temperature on the magnitude of those channels. Neutral species CF{sub 4}, C{sub 2}F{sub 6}, and C{sub 3}F{sub 8} are produced on surfaces. The magnitude of the production channel increases with surface temperature for all species, but favors higher mass species as the temperature is elevated. Additionally, the production rate of CF{sub 2} increases by a factor of 5 as the surface temperature is raised from 25 Degree-Sign C to 200 Degree-Sign C. Fluorine density, on the other hand, does not change as a function of either surface temperature or position outside of the plasma glow. This indicates that fluorine addition in the gas-phase is not a dominant reaction. Heating reactors can result in higher densities of depositing radical species, resulting in increased deposition rates on cooled substrates. Finally, the sticking probability of the depositing free radical species does not change as a function of surface temperature. Instead, the surface temperature acts together with an etchant species (possibly fluorine) to elevate desorption rates on that surface at temperatures lower than those required for unassisted thermal desorption.

  9. Role of surface temperature in fluorocarbon plasma-surface interactions

    International Nuclear Information System (INIS)

    This article examines plasma-surface reaction channels and the effect of surface temperature on the magnitude of those channels. Neutral species CF4, C2F6, and C3F8 are produced on surfaces. The magnitude of the production channel increases with surface temperature for all species, but favors higher mass species as the temperature is elevated. Additionally, the production rate of CF2 increases by a factor of 5 as the surface temperature is raised from 25 °C to 200 °C. Fluorine density, on the other hand, does not change as a function of either surface temperature or position outside of the plasma glow. This indicates that fluorine addition in the gas-phase is not a dominant reaction. Heating reactors can result in higher densities of depositing radical species, resulting in increased deposition rates on cooled substrates. Finally, the sticking probability of the depositing free radical species does not change as a function of surface temperature. Instead, the surface temperature acts together with an etchant species (possibly fluorine) to elevate desorption rates on that surface at temperatures lower than those required for unassisted thermal desorption.

  10. Basic studies on the estimation of climate values (normals for decade air temperature) at unit cell by using satellite data

    International Nuclear Information System (INIS)

    Basic studies on the estimation of normals for decade air temperature at unit cell were performed using daily mean air temperature derived from satellite IR data. Analyses were taken with the assumption that “the difference between a daily mean air temperature and normals for decade air temperature is approximate among areas sharing similar climates”. Items and procedures for analyses are as follows. (1) Characteristic for mean decade air temperature and frequency for decade air temperature. (2) Classification for AMeDAS observation sites in Hokkaido to make some groups of areas sharing similar climates. (3) Characteristic of difference between a daily mean air temperature and normals for decade air temperature, and proof of the assumption. (4) Estimation of daily mean air temperature derived from satellite IR data. (5) Estimation of quasi-normals for decade air temperature using satellite IR data. The results for analyses are as follows. (1) The assumption that the difference between a daily mean air temperature and normals for decade air temperature is approximate among areas sharing similar climates was proved. Therefore, it is possible to estimate quasi-normals for decade air temperature using daily mean air temperature derived from satellite IR data. (2) There was a significance level of 1% between daily mean air temperature of AMeDAS data and surface temperature for 960 cm cell derived from Landsat TM data on July 8, 1993 in Ishikari Plain. And quasi-normals for decade air temperature in early July could be estimated to 0.1°C accuracy, except for data from Eniwa-Shimamatsu AMeDAS observation site. (author)

  11. INTRA URBAN AIR TEMPERATURE DISTRIBUTIONS IN HISTORIC URBAN CENTER

    OpenAIRE

    Elmira Jamei; Dilshan Remaz Ossen

    2012-01-01

    The study investigates the urban heat island effect in Malaysian historic town Malacca through seven mobile traverses, as carried out on 10 December 2011. It aims to identify the intra-urban air temperature differences between heritage core zone, new development area and outskirts of the city. Air temperature variations were also analyzed across three different zones; namely the outskirts, the heritage site and the city center district. Heat index values were then calculated based on air temp...

  12. Daytime sensible heat flux estimation over heterogeneous surfaces using multitemporal land-surface temperature observations

    Science.gov (United States)

    Castellví, F.; Cammalleri, C.; Ciraolo, G.; Maltese, A.; Rossi, F.

    2016-05-01

    Equations based on surface renewal (SR) analysis to estimate the sensible heat flux (H) require as input the mean ramp amplitude and period observed in the ramp-like pattern of the air temperature measured at high frequency. A SR-based method to estimate sensible heat flux (HSR-LST) requiring only low-frequency measurements of the air temperature, horizontal mean wind speed, and land-surface temperature as input was derived and tested under unstable conditions over a heterogeneous canopy (olive grove). HSR-LST assumes that the mean ramp amplitude can be inferred from the difference between land-surface temperature and mean air temperature through a linear relationship and that the ramp frequency is related to a wind shear scale characteristic of the canopy flow. The land-surface temperature was retrieved by integrating in situ sensing measures of thermal infrared energy emitted by the surface. The performance of HSR-LST was analyzed against flux tower measurements collected at two heights (close to and well above the canopy top). Crucial parameters involved in HSR-LST, which define the above mentioned linear relationship, were explained using the canopy height and the land surface temperature observed at sunrise and sunset. Although the olive grove can behave as either an isothermal or anisothermal surface, HSR-LST performed close to H measured using the eddy covariance and the Bowen ratio energy balance methods. Root mean square differences between HSR-LST and measured H were of about 55 W m-2. Thus, by using multitemporal thermal acquisitions, HSR-LST appears to bypass inconsistency between land surface temperature and the mean aerodynamic temperature. The one-source bulk transfer formulation for estimating H performed reliable after calibration against the eddy covariance method. After calibration, the latter performed similar to the proposed SR-LST method.

  13. Air temperature investigation in microenvironment around a human body

    DEFF Research Database (Denmark)

    Licina, Dusan; Melikov, Arsen Krikor; Sekhar, Chandra;

    2015-01-01

    The aim of this study is to investigate the temperature boundary layer around a human body in a quiescent indoor environment. The air temperature, mean in time and standard deviation of the temperature fluctuations around a breathing thermal manikin are examined in relation to the room temperatur...... accurate measurements of occupant's thermal microenvironment....

  14. Clean heating surfaces - a condition for a fuel consumption decrease (air heaters)

    International Nuclear Information System (INIS)

    Unclean heating surface from the water and the flame side has an influence on the exit gas temperature after combustion. That can be noticed from the gas temperature increase, which is a basic indication of the heating surface condition. Unavoidable, the heating surface has to be clean to get a more economical work of the unit. In this paper the means of cleaning air heater heating surfaces from the flame side are given. (author). 2 tabs., 1 fig

  15. Pyrometric Gas and Surface Temperature Measurements

    Science.gov (United States)

    Fralick, Gustave; Ng, Daniel

    1999-01-01

    A multiwavelength pyrometer possessing advantages over the one- and two-wavelength designs is described. Results of its application to surface temperature measurements of ceramics is presented. Also described is a probe suitable for gas temperature measurements to temperatures > 2600 K. The design of the probe includes a multiwavelength pyrometer with fiber optic input.

  16. Pan-Arctic linkages between snow accumulation and growing season air temperature, soil moisture and vegetation

    OpenAIRE

    K. A. Luus; Gel, Y.; J. C. Lin; Kelly, R. E. J.; C. R. Duguay

    2013-01-01

    Arctic field studies have indicated that the air temperature, soil moisture and vegetation at a site influence the quantity of snow accumulated, and that snow accumulation can alter growing season soil moisture and vegetation. Climate change is predicted to bring about warmer air temperatures, greater snow accumulation and northward movements of the shrub and tree lines. Understanding the response of northern environments to changes in snow and growing season land surface characteristi...

  17. Seaport-Surface Transportation Access and Air Quality

    OpenAIRE

    Shaw, Peter L.

    1993-01-01

    Seaports are dependent upon the supporting surface transportation network. Where port cargo volume is growing in already air-polluted urban areas, increased highway and rail traffic is perceived as exacerbating air quality conditions. In some seaport locations, stringent air quality control measures may impact operations and access, thereby possibly causing serious negative impacts on the economy. In still other areas, inadequate air quality controls may inadvertently foster more air pollution.

  18. Guess-Work and Reasonings on Centennial Evolution of Surface Air Temperature in Russia. Part II: Is it Possible to Research Both Local Peculiarities and Regional Tendencies from the Bifurcation Analysis Viewpoint?

    Science.gov (United States)

    Kolokolov, Yury; Monovskaya, Anna

    This paper is devoted to the development of the experimental bifurcation analysis in the research of local climate dynamics. In particular, we consider the dynamics of the land surface air temperature in the centennial timescale. The experimental bifurcation analysis supposes the choice of a conceptual model to demonstrate how the observable kinds of dynamical processes can be realized on the whole. We worked on the conceptual model with a variable structure (HDS-model), where the dynamics is determined by the competition between the amplitude quantization and the time quantization. The model originates from the hysteresis regulator with double synchronization (HDS-regulator) proposed in 1970’s to achieve the extreme combination of both efficiency and reliability of energy conversion processes. The HDS-model allows to consider the interplay between several periodical processes instead of chaos and quasi-periodicity in order to excuse the variety of the behaviors observed in the local climate dynamics. In particular, the intermittency seems to be the typical behavior of a local climate system from such viewpoint. Here we continue to verify the HDS-model and continue to develop the idea of the modified bifurcation diagrams to reveal the regularities within the intermittency. In particular, we first build the spatial diagram to summarize the results of the bifurcation analysis of the local climate dynamics in the centennial timescale. We assume that each effect of the regional temperature oscillations (RTO-effect) appears as a certain combination of several effects of the local temperature oscillations (LTO-effects), where each LTO-effect can be revealed by the bifurcation analysis. The possibility to build the modified bifurcation diagrams is provided by the SUC-logic aimed for the synthesis of experimental bifurcation analysis, symbolical analysis, and multidimensional data visualization under the assumption that an annual warming-cooling cycle is the unit to

  19. Repeat temperature measurements in boreholes from northwestern Utah link ground and air temperature changes at the decadal time scale

    Science.gov (United States)

    Davis, Michael G.; Harris, Robert N.; Chapman, David S.

    2010-05-01

    Borehole temperature profiles provide a record of ground surface temperature (GST) change at the decadal to centennial time scale. GST histories reconstructed from boreholes are particularly useful in climate reconstruction if changes in GST and surface air temperature (SAT) are effectively coupled at decadal and longer time periods and it can be shown that borehole temperatures respond faithfully to surface temperature changes. We test these assumptions using three boreholes in northwestern Utah that have been repeatedly logged for temperature over a time span of 29 years. We report 13 temperature-depth logs at the Emigrant Pass Observatory borehole GC-1, eight at borehole SI-1 and five at borehole DM-1, acquired between 1978 and 2007. Systematic subsurface temperature changes of up to 0.6°C are observed over this time span in the upper sections of the boreholes; below approximately 100 m any temperature transients are within observational noise. We difference the temperature logs to highlight subsurface transients and to remove any ambiguity resulting from steady state source of curvature. Synthetic temperature profiles computed from SAT data at nearby meteorological stations reproduce both the amplitude and pattern of the transient temperature observations, fitting the observations to within 0.03°C or better. This observational confirmation of the strong coupling between surface temperature change and borehole temperature transients lends further support to the use of borehole temperatures to complement SAT and multiproxy reconstructions of climate change.

  20. Development and evaluation of the model for the surface pavement temperature prediction

    Directory of Open Access Journals (Sweden)

    B. Matić

    2012-07-01

    Full Text Available This paper examines the existing models for predicting pavement temperatures and formulates a new one using a regression equation to predict the minimum and maximum pavement surface temperatures depending on the air temperature. Also, the paper presents a model for pavement temperature prediction according to the Superpave methodology and conducts the validation of the model for measured temperatures.

  1. Modeling Apple Surface Temperature Dynamics Based on Weather Data

    OpenAIRE

    Lei Li; Troy Peters; Qin Zhang; Jingjin Zhang; Danfeng Huang

    2014-01-01

    The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00–18:00...

  2. FEATURES OF ROADBED COMPACTION UNDER THE NEGATIVE AIR TEMPERATURES

    OpenAIRE

    Fomenko, E.; Sedov, A

    2005-01-01

    The features of roadbed compaction under negative air temperatures are considered. With the soil temperature decrease, the soil system"s structural resistance to compaction is growing. Attainment of the necessary soil density depends here on an ambient temperature, value and mode of the compaction loading.

  3. Estimation Accuracy of air Temperature and Water Vapor Amount Above Vegetation Canopy Using MODIS Satellite Data

    Science.gov (United States)

    Tomosada, M.

    2005-12-01

    Estimation accuracy of the air temperature and water vapor amount above vegetation canopy using MODIS satellite data is indicated at AGU fall meeting. The air temperature and water vapor amount which are satisfied the multilayer energy budget model from the ground surface to the atmosphere are estimated. Energy budget models are described the fluxes of sensible heat and latent heat exchange for the ground surface and the vegetated surface. Used MODIS satellite data is the vegetated surface albedo which is calculated from visible and near infrared band data, the vegetated surface temperature, NDVI (Normalized Difference Vegetation Index), LAI (Leaf Area Index). Estimation accuracy of air temperature and water vapor amount above vegetation canopy is evaluated comparing with the value which is measured on a flux research tower in Tomakomai northern forest of Japan. Meteorological parameters such as temperature, wind speed, water vapor amount, global solar radiation are measured on a flux tower from the ground to atmosphere. Well, MODIS satellite observes at day and night, and it snows in Tomakomai in winter. Therefore, estimation accuracy is evaluated dividing on at daytime, night, snowfall day, and not snowfall day. There is the investigation of the undeveloped region such as dense forest and sea in one of feature of satellite observation. Since there is almost no meteorological observatory at the undeveloped region so far, it is hard to get the meteorological parameters. Besides, it is the one of the subject of satellite observation to get the amount of physical parameter. Although the amount of physical parameter such as surface temperature and concentration of chlorophyll-a are estimated by satellite, air temperature and amount of water vapor above vegetation canopy have not been estimated by satellite. Therefore, the estimation of air temperature and water vapor amount above vegetation canopy using satellite data is significant. Further, a highly accurate

  4. Guess-Work and Reasonings on Centennial Evolution of Surface Air Temperature in Russia. Part III: Where is the Joint Between Norms and Hazards from a Bifurcation Analysis Viewpoint?

    Science.gov (United States)

    Kolokolov, Yury; Monovskaya, Anna

    2016-06-01

    The paper continues the application of the bifurcation analysis in the research on local climate dynamics based on processing the historically observed data on the daily average land surface air temperature. Since the analyzed data are from instrumental measurements, we are doing the experimental bifurcation analysis. In particular, we focus on the discussion where is the joint between the normal dynamics of local climate systems (norms) and situations with the potential to create damages (hazards)? We illustrate that, perhaps, the criteria for hazards (or violent and unfavorable weather factors) relate mainly to empirical considerations from human opinion, but not to the natural qualitative changes of climate dynamics. To build the bifurcation diagrams, we base on the unconventional conceptual model (HDS-model) which originates from the hysteresis regulator with double synchronization. The HDS-model is characterized by a variable structure with the competition between the amplitude quantization and the time quantization. Then the intermittency between three periodical processes is considered as the typical behavior of local climate systems instead of both chaos and quasi-periodicity in order to excuse the variety of local climate dynamics. From the known specific regularities of the HDS-model dynamics, we try to find a way to decompose the local behaviors into homogeneous units within the time sections with homogeneous dynamics. Here, we present the first results of such decomposition, where the quasi-homogeneous sections (QHS) are determined on the basis of the modified bifurcation diagrams, and the units are reconstructed within the limits connected with the problem of shape defects. Nevertheless, the proposed analysis of the local climate dynamics (QHS-analysis) allows to exhibit how the comparatively modest temperature differences between the mentioned units in an annual scale can step-by-step expand into the great temperature differences of the daily

  5. Determination of needed parameters for measuring temperature fields in air by thermography

    Science.gov (United States)

    Pešek, Martin; Pavelek, Milan

    2012-04-01

    The aim of this article is the parameters determination of equipment for measuring temperature fields in air using an infrared camera. This method is based on the visualization of temperature fields in an auxiliary material, which is inserted into the non-isothermal air flow. The accuracy of air temperature measurement (or of surface temperature of supplies) by this method depends especially on (except for parameters of infrared camera) the determination of the static and the dynamic qualities of auxiliary material. The emissivity of support material is the static quality and the dynamic quality is time constant. Support materials with a high emissivity and a low time constant are suitable for the measurement. The high value of emissivity results in a higher measurement sensitivity and the radiation temperature independence. In this article the emissivity of examined kinds of auxiliary materials (papers and textiles) is determined by temperature measuring of heated samples by a calibrated thermocouple and by thermography, with the emissivity setting on the camera to 1 and with the homogeneous radiation temperature. Time constants are determined by a step change of air temperature in the surrounding of auxiliary material. The time constant depends mainly on heat transfer by the convection from the air into the auxiliary material. That is why the effect of air temperature is examined in this article (or a temperature difference towards the environmental temperature) and the flow velocity on the time constant with various types of auxiliary materials. The obtained results allow to define the conditions for using the method of measurement of temperature fields in air during various heating and air conditioning applications.

  6. Temperature control apparatus including air return bulkhead for mounting in a transportable body

    Energy Technology Data Exchange (ETDEWEB)

    Zajic, A.H.

    1988-02-23

    An air return bulkhead assembly for removable installation adjacent an inside surface of a front wall of a trailer also having two side walls extending from opposite ends of the front wall, through which front wall is disposed an air treatment apparatus for receiving air through an inlet, for temperature treating the air and for providing the temperature-treated air through an outlet is described comprising: a first vertical support member having a first web through which a first hole is defined; first attachment means for attaching the first vertical support member to the front wall of the trailer between one of the side walls of the trailer and the air treatment apparatus.

  7. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region

    Science.gov (United States)

    Oikawa, P. Y.; Ge, C.; Wang, J.; Eberwein, J. R.; Liang, L. L.; Allsman, L. A.; Grantz, D. A.; Jenerette, G. D.

    2015-11-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality.

  8. Worldwide surface temperature trends since the mid-19th century

    International Nuclear Information System (INIS)

    Sea surface temperatures (SSTs) for the period 1856 to the present have been corrected to compensate for the use of uninsulated buckets prior to the early 1940s. Trends in the corrected SST are consistent with trends in independently corrected nighttime marine air temperatures (NMAT). Global-scale patterns of variation of annual anomalies of SST and NMAT, as revealed by the first three covariance eigenvectors, are also in close agreement. The corrected SST anomalies are also compared with those of nearby coastal and island land air temperatures. Global-scale agreement is good except in the early 20th century when the land data were relatively warm by up to 0.2 C. Proposed causes are the siting of thermometers in open-sided thatched sheds in tropical regions at that time, along with a marked tendency to warm westerly atmospheric circulation over Europe in winter. Combined fields of SST and land air temperature are presented. The relative overall coldness of the late 19th century land air temperatures appears to have arisen from inner-continental and high-latitude regions, especially in winter. Combined fields do not yield full global coverage even in the 1980s, so satellite-based SST data need to be blended carefully with the ship-based observations if monitoring of global climate is to be complete

  9. Worldwide surface temperature trends since the mid-19th century

    International Nuclear Information System (INIS)

    Sea surface temperatures (SSTs) for the period 1856 to the present have been corrected to compensate for the use of uninsulated buckets prior to the early 1940s. Trends in the corrected SST are consistent with trends in independently corrected nighttime marine air temperatures (NMAT). Global-scale patterns of variation of annual anomalies of SST and NMAT, as revealed by the first three covariance eigenvectors, are also in close agreement. The corrected SST anomalies are also compared with those of nearby coastal and island land air temperatures. Global-scale agreement is good except in the early 20th century when the land data were relatively warm by up to 0.2 C. Proposed causes are the siting of thermometers in open-sided thatched sheds in tropical regions at that time, along with a marked tendency to warm westerly atmospheric circulation over Europe in winter. Combined fields of SST and land air temperature are presented. The relative overall coldness of the late 19th century land air temperatures appears to have arisen from inner-continental and high-latitude regions, especially in winter. Combined fields do not yield full global coverage even in the 1980s, so satellite-based SST data need to be blended carefully with the ship-based observations if monitoring of global climate is to be complete. 32 refs.; 16 figs

  10. A comparison of urban heat islands mapped using skin temperature, air temperature, and apparent temperature (Humidex), for the greater Vancouver area.

    Science.gov (United States)

    Ho, Hung Chak; Knudby, Anders; Xu, Yongming; Hodul, Matus; Aminipouri, Mehdi

    2016-02-15

    Apparent temperature is more closely related to mortality during extreme heat events than other temperature variables, yet spatial epidemiology studies typically use skin temperature (also known as land surface temperature) to quantify heat exposure because it is relatively easy to map from satellite data. An empirical approach to map apparent temperature at the neighborhood scale, which relies on publicly available weather station observations and spatial data layers combined in a random forest regression model, was demonstrated for greater Vancouver, Canada. Model errors were acceptable (cross-validated RMSE=2.04 °C) and the resulting map of apparent temperature, calibrated for a typical hot summer day, corresponded well with past temperature research in the area. A comparison with field measurements as well as similar maps of skin temperature and air temperature revealed that skin temperature was poorly correlated with both air temperature (R(2)=0.38) and apparent temperature (R(2)=0.39). While the latter two were more similar (R(2)=0.87), apparent temperature was predicted to exceed air temperature by more than 5 °C in several urban areas as well as around the confluence of the Pitt and Fraser rivers. We conclude that skin temperature is not a suitable proxy for human heat exposure, and that spatial epidemiology studies could benefit from mapping apparent temperature, using an approach similar to the one reported here, to better quantify differences in heat exposure that exist across an urban landscape. PMID:26706765

  11. Sea Surface Temperature Average_SST_Master

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sea surface temperature collected via satellite imagery from http://www.esrl.noaa.gov/psd/data/gridded/data.noaa.ersst.html and averaged for each region using...

  12. Sea Surface Temperature (14 KM North America)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Product shows local sea surface temperatures (degrees C). It is a composite gridded-image derived from 8-km resolution SST Observations. It is generated every 48...

  13. EROS MODIS Land Surface Temperature: 2002-Present

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The EROS Moderate Resolution Imaging Spectroradiometer (eMODIS) Aqua Land Surface Temperature (LST) product is similar to the Land Processes Distributed Active...

  14. Surface Air Temp erature Simulations over China with CMIP5 and CMIP3

    Institute of Scientific and Technical Information of China (English)

    GUO Yan; DONG Wen-Jie; REN Fu-Min; ZHAO Zong-Ci; HUANG Jian-Bin

    2013-01-01

    Historical simulations of annual mean surface air temperature over China with 25 CMIP5 models were assessed. The observational data from CRUT3v and CN05 were used and further compared with historical simulations of CMIP3. The results show that CMIP5 models were able to simulate the observed warming over China from 1906 to 2005 (0.84◦C per 100 years) with a warming rate of 0.77◦C per 100 years based on the multi-model ensemble (MME). The simulations of surface air temperature in the late 20th century were much better than those in the early 20th century, when only two models could reproduce the extreme warming in the 1940s. The simulations for the spatial distribution of the 20-year-mean (1986-2005) surface air temperature over China fit relatively well with the observations. However, underestimations in surface air temperature climatology were still found almost all over China, and the largest cold bias and simulation uncertainty were found in western China. On sub-regional scale, northern China experienced stronger warming than southern China during 1961-1999, for which the CMIP5 MME provided better simulations. With CMIP5 the difference of warming trends in northern and southern China was underestimated. In general, the CMIP5 simulations are obviously improved in comparison with the CMIP3 simulations in terms of the variation in regional mean surface air temperature, the spatial distribution of surface air temperature climatology and the linear trends in surface air temperature all over China.

  15. BMA Probabilistic Forecasting for the 24-h TIGGE Multi-model Ensemble Forecasts of Surface Air Temperature%基于TIGGE多模式集合的24小时气温BMA概率预报

    Institute of Scientific and Technical Information of China (English)

    刘建国; 谢正辉; 赵琳娜; 贾炳浩

    2013-01-01

    利用TIGGE (THORPEX Interactive Grand Global Ensemble)单中心集合预报系统(ECMWF、United Kingdom Meteorological Office、China Meteorological Administration和NCEP)以及由此所构成的多中心模式超级集合预报系统24小时地面日均气温预报,结合淮河流域地面观测率定贝叶斯模型平均(Bayesian model averaging,BMA)参数,从而建立地面日均气温BMA概率预报模型.由此针对淮河流域进行地面日均气温BMA概率预报及其检验与评估,结果表明BMA模型比原始集合预报效果好;单中心的BMA概率预报都有较好的预报效果,其中ECMWF最好.多中心模式超级集合比单中心BMA概率预报效果更好,采用可替换原则比普通的多中心模式超级集合BMA模型计算量小,且在上述BMA集合预报系统中效果最好.它与原始集合预报相比其平均绝对误差减少近7%,其连续等级概率评分提高近10%.基于采用可替换原则的多中心模式超级集合BMA概率预报,针对研究区域提出了极端高温预警方案,这对防范高温天气有着重要意义.%Bayesian model averaging (BMA) probability forecast models were established through calibration of their parameters using 24-h ensemble forecasts of average daily surface air temperature provided by single-center ensemble prediction systems (EPSs) from the following agencies: the European Centre for Medium-Range Weather Forecasts (ECMWF), the United Kingdom Meteorological Office (UKMO), the China Meteorological Administration (CMA), and the United States National Center for Environmental Prediction (NCEP) and its multi-center model grand-ensemble (GE) EPSs in the THORPEX Interactive Grand Global Ensemble (TIGGE), and observations in the Huaihe basin. The BMA probability forecasts of average daily surface air temperature for different EPSs were assessed by comparison with observations in the Huaihe basin. The results suggest that performance was better in the BMA predictive models than

  16. MAIC-2, a latitudinal model for the Martian surface temperature, atmospheric water transport and surface glaciation

    CERN Document Server

    Greve, Ralf; Stenzel, Oliver J

    2009-01-01

    The Mars Atmosphere-Ice Coupler MAIC-2 is a simple, latitudinal model, which consists of a set of parameterizations for the surface temperature, the atmospheric water transport and the surface mass balance (condensation minus evaporation) of water ice. It is driven directly by the orbital parameters obliquity, eccentricity and solar longitude (Ls) of perihelion. Surface temperature is described by the Local Insolation Temperature (LIT) scheme, which uses a daily and latitude-dependent radiation balance, includes a treatment of the seasonal CO2 cap, and has been validated against the surface temperatures from the Mars Climate Database. The evaporation rate of water is calculated by an expression for free convection, driven by density differences between water vapor and ambient air, and the condensation rate follows from the assumption that any water vapour which exceeds the local saturation pressure condenses instantly. Atmospheric transport of water vapour is assumed to be purely diffusive, with an adjustable...

  17. NOS CO-OPS Meteorological Data, Air Temperature, 6-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has Air Temperature data from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS). WARNING: These preliminary data have not...

  18. Associations of endothelial function and air temperature in diabetic subjects

    Science.gov (United States)

    Background and Objective: Epidemiological studies consistently show that air temperature is associated with changes in cardiovascular morbidity and mortality. However, the biological mechanisms underlying the association remain largely unknown. As one index of endothelial functio...

  19. TAO/TRITON, RAMA, and PIRATA Buoys, Quarterly, Air Temperature

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has quarterly Air Temperature data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  20. TAO/TRITON, RAMA, and PIRATA Buoys, Monthly, Air Temperature

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has monthly Air Temperature data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  1. Impact of temperature and humidity on perceived indoor air quality

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Lei

    1997-11-01

    This thesis deals with the impact of temperature and humidity on the emission of pollutants from five building materials and on the perception of air polluted by the material emissions. The impact was studied in the temperature range 18-28 deg. C and the humidity range 30-70%RH, corresponding to conditions often pertaining in normal non-industrial indoor environments. The five building materials used in the study were: PVC flooring, waterborne acrylic floor varnish, loomed polyamide carpet with latex backing, waterborn acrylic wall paint and acrylic sealant; all these materials are commonly use din buildings. The effect of temperature and humidity on emission and perception of air pollutant emitted from the five building materials is described, using a specially developed exposure system. A computer-controlled exposure system was developed. The design of the system allowed the impact of temperature and humidity on the emission of pollutants from the materials to be judged separately from the impact on perception. The effect of temperature and humidity on emission and on perception was investigated at nine different combinations of three temperature levels 18 deg. C, 23 deg. C, 28 deg. C and three relative humidity levels 30%, 50%, 70%. A sensory panel assessed the acceptability of the air after facial exposure. Chemical measurements of the pollutants emitted were also made. The impact of temperature and humidity on perception of air quality during whole-body exposure is discussed. The influence of the pre-exposure temperature/humidity on perception of air quality and the time course of adaptation of air quality perception with different combinations of temperature and humidity were also investigated. It is recommended that future ventilation standards should include the effect of indoor air temperature and humidity in ventilation requirements. (EG) 86 refs.

  2. OSCILLATIONS AND CYCLES OF AIR TEMPERATURE IN SOUTH AMERICA

    OpenAIRE

    Ion Isaia

    2013-01-01

    This paper is seeking to prove that on the South American continent there are the same cycles of air temperature (almost perfect) as those proven to exist in Europe (Romania), New Zeeland and North America (the U.S.A.) The oscillations and air temperature cycles of South America have their own characteristics, due to the large expansion of this continent in both latitude and longitude. The absence of important mountain chains with longitudinal display allows quick and intense advection of bot...

  3. EFFECT OF AIR TEMPERATURE ON LEAF PHOTOSYNTHESIS IN ELDER

    Directory of Open Access Journals (Sweden)

    Monica Popescu

    2012-12-01

    Full Text Available Temperature with solar radiation intensity is the main external factor affecting photosynthesis process. Measurements were collected in the 2011 growing season. Photosynthesis and respiration measurements were made at Sambucus nigra leaves with a CO2 analyzer. The aim was to develop a model of photosynthesis in relation to temperature (which is in close relationship with air humidity. Photosynthesis of Sambucus nigra leaves is sensitive to temperature with an optimum around 25-28oC and rates declining by 18% with air temperature around 33-35oC.

  4. Superhydrophobic condenser surfaces for air gap membrane distillation

    OpenAIRE

    Swaminathan, Jaichander; Maswadeh, Laith A.; Warsinger, David Elan Martin; Lienhard, John H.

    2015-01-01

    Superhydrophobic surfaces for enhanced condensation in air gap membrane distillation (AGMD) may provide significantly improved distillate production rates and increased thermal efficiency. While AGMD is one of the most thermally efficient membrane distillation desalination configurations, large transport resistances in the air gap limit distillate production rates. AGMD experiments were performed with combinations of untreated, hydrophobic, and superhydrophobic condensation surfaces. A nanost...

  5. Air and permafrost temperature at Mt. Melbourne (1989-1998)

    OpenAIRE

    Gambino, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia

    2005-01-01

    Ten years, from 1989 to 1998, of continuous recording of air and permafrost temperature at Mt. Melbourne has been analysed considering daily and seasonal changes. Published historical temperature observations in this area are absent. Temperature signals have been recorded by a permanent geophysical network operating since 1989 on Mt Melbourne volcano composed of five stations each equipped with four temperature sensors installed at different depths with a 48 data/day sampling. The netwo...

  6. Concentration of 7Be in surface air at Suva, Fiji

    International Nuclear Information System (INIS)

    A high-volume air sampler and a high-resolution gamma-ray spectrometer have been in use since August 1997 at the University of the South Pacific to measure the activity of 7Be in surface air at Suva, the capital city of Fiji. Preliminary measurements during August - November 1997 indicate that the average concentration of 7Be in surface air is approximately 4.0 mBq m-3. Further measurements are in progress

  7. Estimating Air Temperature over the Tibetan Plateau Using MODIS Data

    Science.gov (United States)

    Huang, Fangfang; Ma, Weiqiang; Ma, Yaoming; Li, Maoshan; Hu, Zeyong

    2016-04-01

    Time series of MODIS land surface temperature (LST) data and normalized difference vegetation index (NDVI) data, combined with digital elevation model (DEM) and meterological data for 2001-2012, were used to estimate and map the spatial distribution of monthly mean air temperature over the Tibatan Plateau (TP). Time series and regression analysis of monthly mean land surface temperature (Ts) and air temperature (Ta) were both conducted by ordinary liner regression (OLR) and geographical weighted regression (GWR) methods. Analysis showed that GWR method had much better result (Adjusted R2 > 0.79, root mean square error (RMSE) is between 0.51° C and 1.12° C) for estimating Ta than OLR method. The GWR model, with MODIS LST, NDVI and altitude as independent variables, was used to estimate Ta over the Tibetan Plateau. All GWR models in each month were tested by F-test with significant level of α=0.01 and the regression coefficients were all tested by T-test with significant level of α=0.01. This illustrated that Ts, NDVI and altitude play an important role on estimating Ta over the Tibetan Plateau. Finally, the major conclusions are as follows: (1) GWR method has higher accuracy for estimating Ta than OLR (Adjusted R2=0.40˜0.78, RMSE=1.60˜4.38° C), and the Ta control precision can be up to 1.12° C. (2) Over the Northern TP, the range of Ta variation in January is -29.28 ˜ -5.0° C, and that in July is -0.53 ˜ 14.0° C. Ta in summer half year (from May to October) is between -15.92 ˜ 14.0° C. From October on, 0° C isothermal level is gradually declining from the altitude of 4˜5 kilometers, and hits the bottom with altitude of 3200 meters in December, and Ta is all under 0° C in January. 10° C isothermal level gradually starts rising from the altitude of 3200 meters from May, and reaches the highest level with altitude of 4˜5 kilometers in July. In addition, Ta in south slope of the Tanggula Mountains is obviously higher than that in the north slope. Ta

  8. Interactive short-term effects of equivalent temperature and air pollution on human mortality in Berlin and Lisbon

    International Nuclear Information System (INIS)

    There is substantial evidence that both temperature and air pollution are predictors of mortality. Thus far, few studies have focused on the potential interactive effects between the thermal environment and different measures of air pollution. Such interactions, however, are biologically plausible, as (extreme) temperature or increased air pollution might make individuals more susceptible to the effects of each respective predictor. This study investigated the interactive effects between equivalent temperature and air pollution (ozone and particulate matter) in Berlin (Germany) and Lisbon (Portugal) using different types of Poisson regression models. The findings suggest that interactive effects exist between air pollutants and equivalent temperature. Bivariate response surface models and generalised additive models (GAMs) including interaction terms showed an increased risk of mortality during periods of elevated equivalent temperatures and air pollution. Cold effects were mostly unaffected by air pollution. The study underscores the importance of air pollution control in mitigating heat effects. -- Highlights: • Interactive effects between air pollution and equivalent temperature result in augmented excess mortality. • High levels of ozone and particulate matter increase adverse heat effects on human mortality. • Cold effects are mostly unaffected by air pollution. • Findings underscore the importance of air pollution control in mitigating heat-related mortality. -- Interactive effects between air pollution and elevated (equivalent) temperatures underscore the importance of air pollution control in mitigating the adverse effects of heat

  9. Modeling apple surface temperature dynamics based on weather data.

    Science.gov (United States)

    Li, Lei; Peters, Troy; Zhang, Qin; Zhang, Jingjin; Huang, Danfeng

    2014-01-01

    The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00-18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of "Fuji" apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management. PMID:25350507

  10. Modeling Apple Surface Temperature Dynamics Based on Weather Data

    Directory of Open Access Journals (Sweden)

    Lei Li

    2014-10-01

    Full Text Available The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed was recorded for seven hours between 11:00–18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of “Fuji” apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management.

  11. Impact of air temperature, relative humidity, air movement and pollution on eye blinking

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Lyubenova, Velina S.; Skwarczynski, Mariusz;

    2011-01-01

    The effect of indoor air temperature, relative humidity, velocity and pollution on occupants’ eye blink frequency (BF) was examined. In total sixty subjects participated in eight 4 hour experiments without and with facially applied air movement under individual control of the subjects. Air movement...... of either polluted room air supplied isothermally or clean and cool air was used. Eye blinking video record for the last 15 min of each exposure were analysed. The increase of the room air temperature and relative humidity from 23 °C and 40% to 26 °C and 70% or to 28 °C and 70% decreased the BF....... At temperature of 26 °C and relative humidity of 70% facially applied flow of polluted room air didn’t have significant impact on BF in comparison without air movement. The increase of BF due to decrease of temperature and humidity and increase of velocity may be compensated due to the increase in air cleanness....

  12. Impact of air temperature, relative humidity, air movement and pollution on eye blinking

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Lyubenova, Velina S.; Skwarczynski, Mariusz; Kaczmarczyk, Jan

    2011-01-01

    The effect of indoor air temperature, relative humidity, velocity and pollution on occupants’ eye blink frequency (BF) was examined. In total sixty subjects participated in eight 4 hour experiments without and with facially applied air movement under individual control of the subjects. Air movement...... of either polluted room air supplied isothermally or clean and cool air was used. Eye blinking video record for the last 15 min of each exposure were analysed. The increase of the room air temperature and relative humidity from 23 °C and 40% to 26 °C and 70% or to 28 °C and 70% decreased the BF. At...... temperature of 26 °C and relative humidity of 70% facially applied flow of polluted room air didn’t have significant impact on BF in comparison without air movement. The increase of BF due to decrease of temperature and humidity and increase of velocity may be compensated due to the increase in air cleanness....

  13. Temperature distribution in graphite during annealing in air cooled reactors

    International Nuclear Information System (INIS)

    A model for the evaluation temperature distributions in graphite during annealing operation in graphite. Moderated an-cooled reactors, is presented. One single channel and one dimension for air and graphite were considered. A numerical method based on finite control volumes was used for partioning the mathematical equations. The problem solution involves the use of unsteady equations of mass, momentum and energy conservation for air, and energy conservation for graphite. The source term was considered as stored energy release during annealing for describing energy conservation in the graphite. The coupling of energy conservation equations in air and graphite is performed by the heat transfer term betwen air and graphite. The results agree with experimental data. A sensitivity analysis shown that the termal conductivity of graphite and the maximum inlet channel temperature have great effect on the maximum temperature reached in graphite during the annealing. (author)

  14. Urban heat : natural and anthropogenic factors influencing urban air temperatures

    NARCIS (Netherlands)

    Theeuwes, N.E.

    2015-01-01

    The urban heat island effect is a phenomenon observed worldwide, i.e. evening and nocturnal temperatures in cities are usually several degrees higher than in the surrounding countryside. The main goal of this thesis is to understand the processes that drive the urban air temperature and the urban he

  15. International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 1 Monthly

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The global land surface temperature databank contains monthly timescale mean, max, and min temperature for approximately 40,000 stations globally. It was developed...

  16. International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 3 Monthly

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Land Surface Temperature Databank contains monthly timescale mean, maximum, and minimum temperature for approximately 40,000 stations globally. It was...

  17. International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 1 Daily

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The global land surface temperature databank contains monthly timescale mean, max, and min temperature for approximately 40,000 stations globally. It was developed...

  18. International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 2 Daily

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The global land surface temperature databank contains monthly timescale mean, max, and min temperature for approximately 40,000 stations globally. It was developed...

  19. International Surface Temperature Initiative (ISTI) Global Land Surface Temperature Databank - Stage 2 Monthly

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The global land surface temperature databank contains monthly timescale mean, max, and min temperature for approximately 40,000 stations globally. It was developed...

  20. A coupled surface/subsurface flow model accounting for air entrapment and air pressure counterflow

    DEFF Research Database (Denmark)

    Delfs, Jens Olaf; Wang, Wenqing; Kalbacher, Thomas; Singh, Ashok; Kolditz, Olaf

    2013-01-01

    This work introduces the soil air system into integrated hydrology by simulating the flow processes and interactions of surface runoff, soil moisture and air in the shallow subsurface. The numerical model is formulated as a coupled system of partial differential equations for hydrostatic (diffusive...... the mass exchange between compartments. A benchmark test, which is based on a classic experimental data set on infiltration excess (Horton) overland flow, identified a feedback mechanism between surface runoff and soil air pressures. Our study suggests that air compression in soils amplifies surface...

  1. Temperature measurement at the end of a cantilever using oxygen paramagnetism in solid air

    CERN Document Server

    Thurber, K R; Smith, D D; Thurber, Kent R.; Harrell, Lee E.; Smith, Doran D.

    2003-01-01

    We demonstrate temperature measurement of a sample attached to the end of a cantilever using cantilever magnetometry of solid air ``contamination'' of the sample surface. In experiments like our Magnetic Resonance Force Microscopy (MRFM), the sample is mounted at the end of a thin cantilever with small thermal conductance. Thus, the sample can be at a significantly different temperature than the bulk of the instrument. Using cantilever magnetometry of the oxygen paramagnetism in solid air provides the temperature of the sample, without any modifications to our MRFM (Magnetic Resonance Force Microscopy) apparatus.

  2. High temperature decontamination of stainless steel surfaces

    International Nuclear Information System (INIS)

    Dilute Chemical Decontamination process that is carried out at low temperatures (<90 °C) is effective in obtaining good decontamination factors (DFs) on carbon steel (CS) system surfaces of PHWRs as the formulation is efficient in dissolving magnetite present on CS surfaces. However, this low temperature dilute chemical decontamination process is not effective in achieving appreciable DFs on stainless steel (SS) surfaces of nuclear power reactors as it is not efficient in dissolving Cr and Ni substituted oxides present on these surfaces. Hence, a high temperature process was evaluated for the effective decontamination of SS surfaces. Among the various formulations evaluated, formulation consisting of 5 mM NTA and 10 mM N2H4 at 160 °C was found to be appropriate for high temperature decontamination application. Dissolution of various oxides like, magnetite (Fe3O4), mixed ferrites (NiFe2O4, ZnFe2O4, MgFe2O4 etc), Cr oxide (Cr2O3), bonaccordite (Ni2FeBO5) etc. was carried out in NTA at 160 °C. Significant increase in dissolution rate was observed for these oxides at 160 °C. On increasing the temperature from 80 to 180 °C, the dissolution rate of Fe3O4 increased about 6 fold. The optimised formulation (5 mM NTA with 10 mM N2H4) was employed for removing the oxide formed on SS-304, SS-316, SS-403 and SS-410 under simulated reactor water chemistry conditions. Oxide deposits from all the above surfaces could be completely removed by this high temperature process. This paper gives the summary of the results from the laboratory experiments and a simulated high temperature decontamination process. (author)

  3. Low temperature catalytic combustion of natural gas - hydrogen - air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Newson, E.; Roth, F. von; Hottinger, P.; Truong, T.B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The low temperature catalytic combustion of natural gas - air mixtures would allow the development of no-NO{sub x} burners for heating and power applications. Using commercially available catalysts, the room temperature ignition of methane-propane-air mixtures has been shown in laboratory reactors with combustion efficiencies over 95% and maximum temperatures less than 700{sup o}C. After a 500 hour stability test, severe deactivation of both methane and propane oxidation functions was observed. In cooperation with industrial partners, scaleup to 3 kW is being investigated together with startup dynamics and catalyst stability. (author) 3 figs., 3 refs.

  4. BUILDINGS DENSITY AND THE AIR TEMPERATURE OF URBAN AREA

    OpenAIRE

    BARBARA ŚLESAK; DAMIAN ABSALON

    2012-01-01

    Buildings density and the air temperature of urban area. This paper attempts to assess the impact of air temperature increase connected with the degree of anthropogenic transformation of an area on the subjectively perceived quality of life. The area under study is the Metropolitan Association of Upper Silesia (Polish: Górnośląski Związek Metropolitalny – GZM). We analyzed the average monthly temperatures in different seasons and compared with size and density of buildings in the analyzed are...

  5. Ambient air temperature effects on the temperature of sewage sludge composting process

    Institute of Scientific and Technical Information of China (English)

    HUANG Qi-fei; CHEN Tong-bin; GAO Ding; HUANG Ze-chun

    2005-01-01

    Using data obtained with a full-scale sewage sludge composting facility, this paper studied the effects of ambient air temperature on the composting temperature with varying volume ratios of sewage sludge and recycled compost to bulking agent. Two volume ratios were examined experimentally, 1: 0: 1 and 3: 1: 2. The results show that composting temperature was influenced by ambient air temperature and the influence was more significant when composting was in the temperature rising process: composting temperature changed 2.4-6.5℃ when ambient air temperature changed 13℃. On the other hand, the influence was not significant when composting was in the high-temperature and/or temperature falling process: composting temperature changed 0.75-1.3℃ when ambient air temperature changed 8-15 ℃. Hysteresis effect was observed in composting temperature's responses to ambient air temperature. When the ventilation capability of pile was excellent(at a volume ratio of 1:0:1), the hysteresis time was short and ranging 1.1-1.2 h. On the contrary, when the proportion of added bulking agent was low, therefore less porosity in the substrate(at a volume ratio of 3:1:2), the hysteresis time was long and ranging 1.9-3.1 h.

  6. The spatial diversification of the maximum air temperature in various landforms

    Directory of Open Access Journals (Sweden)

    Grzegorz B. Durło

    2009-12-01

    Full Text Available The knowledge of frequency and probability of the occurrence of the maximum temperature in different forms of sculpture of the earth's surface plays an important role in silviculture, especially in the case of formation of plant communities resistant to stress caused by excessive water losses The spatial diversification of the maximum air temperature in various landforms was investigated. The results of meteorological measurements originated from two regions of southern Poland: the Cracow-Czestochowa Upland and the Beskid Sadecki Mountain Range of the Polish Carpathians. The material contains results of 84 measurement series from 160 experimental posts in 2003--2006 years. The model of diversification of air maximum temperature was elaborated by geostatistical methods and GIS tools. The deviations of the maximum air temperature may be used in the cartographic elaborations concerning the spatial distribution of air temperature in upland and mountain areas where the number of measuring stations is inadequate. The greatest deviations of the maximum air temperature occur in the middle part of gentle slopes of southern exposure, while the smallest ones in the lower part of steep slopes of northern exposure The extremely-high temperature indexes can help identifying the areas where high risk of temperature stress for plants occurs.

  7. Influence of the convective surface transfer coefficients on the Heat, Air, and Moisture (HAM) building performance

    DEFF Research Database (Denmark)

    Steskens, Paul Wilhelmus Maria Hermanus; Janssen, Hans; Rode, Carsten

    2009-01-01

    Current models to predict heat, air and moisture (HAM) conditions in buildings assume constant boundary conditions for the temperature and relative humidity of the neighbouring air and for the surface heat and moisture transfer coefficients. These assumptions may introduce errors in the predicted...... HAM conditions. The paper focuses on the influence of the interior surface heat and moisture transfer coefficients, and investigates its effect on the hygrothermal performance. The parameter study showed that the magnitude of the convective surface transfer coefficients have a relatively large...... influence on the predicted hygrothermal conditions at the surface of a building component and on the heat and vapour exchange with the indoor environment....

  8. Distributed modeling of monthly air temperatures over the rugged terrain of the Yellow River Basin

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Our analyses of the monthly mean air temperature of meteorological stations show that altitude,global solar radiation and surface effective radiation have a significant impact on air temperature.We set up a physically-based empirical model for monthly air temperature simulation.Combined the proposed model with the distributed modeling results of global solar radiation and routine meteorological observation data,we also developed a method for the distributed simulation of monthly air temperatures over rugged terrain.Spatial distribution maps are generated at a resolution of 1 km×1 km for the monthly mean,the monthly mean maximum and the monthly mean minimum air temperatures for the Yellow River Basin.Analysis shows that the simulation results reflect to a considerable extent the macro and local distribution characteristics of air temperature.Cross-validation shows that the proposed model displays good stability with mean absolute bias errors of 0.19℃-0.35℃.Tests carried out on local meteorological station data and case year data show that the model has good spatial and temporal simulation capacity.The proposed model solely uses routine meteorological data and can be applied easily to other regions.

  9. Modelling global fresh surface water temperature

    OpenAIRE

    Beek, L.P.H. van; Eikelboom, T.; van Vliet, M.T.H.; M. F. P. Bierkens

    2011-01-01

    Temperature directly determines a range of water physical properties including vapour pressure, surface tension, density and viscosity, and the solubility of oxygen and other gases. Indirectly water temperature acts as a strong control on fresh water biogeochemistry, influencing sediment concentration and transport, water quality parameters (e.g. pH, nitrogen, phosphor, dissolved oxygen), chemical reaction rates, phytoplankton and zooplankton composition and the presence or absence of pathoge...

  10. Improving the performance of temperature index snowmelt model of SWAT by using MODIS land surface temperature data.

    Science.gov (United States)

    Yang, Yan; Onishi, Takeo; Hiramatsu, Ken

    2014-01-01

    Simulation results of the widely used temperature index snowmelt model are greatly influenced by input air temperature data. Spatially sparse air temperature data remain the main factor inducing uncertainties and errors in that model, which limits its applications. Thus, to solve this problem, we created new air temperature data using linear regression relationships that can be formulated based on MODIS land surface temperature data. The Soil Water Assessment Tool model, which includes an improved temperature index snowmelt module, was chosen to test the newly created data. By evaluating simulation performance for daily snowmelt in three test basins of the Amur River, performance of the newly created data was assessed. The coefficient of determination (R (2)) and Nash-Sutcliffe efficiency (NSE) were used for evaluation. The results indicate that MODIS land surface temperature data can be used as a new source for air temperature data creation. This will improve snow simulation using the temperature index model in an area with sparse air temperature observations. PMID:25165746

  11. Investigation of the impact of extreme air temperature on river water temperature: case study of the heat episode 2013.

    Science.gov (United States)

    Weihs, Philipp; Trimmel, Heidelinde; Goler, Robert; Formayer, Herbert; Holzapfel, Gerda; Rauch, Hans Peter

    2014-05-01

    Water stream temperature is a relevant factor for water quality since it is an important driver of water oxygen content and in turn also reduces or increases stress on the aquatic fauna. The water temperature of streams is determined by the source and inflow water temperature, by the energy balance at the stream surface and by the hydrological regime of the stream. Main factors driving the energy balance of streams are radiation balance and air temperature which influences the sensitive and latent heat flux. The present study investigates the impact of the heat episode of summer 2013 on water temperature of two lowland rivers in south eastern Austria. Within the scope of the project BIO_CLIC routine measurements of water temperature at 33 locations alongside the rivers Pinka and Lafnitz have been performed since spring 2012. In addition meteorological measurements of global shortwave and longwave radiation, air temperature, wind and air humidity have been carried out during this time. For the same time period, data of discharge and water levels of both rivers were provided by the public hydrological office. The heat episode of summer 2013 started, according to the Kysely- definition, on 18 July and lasted until 14 August. The highest air temperature ever recorded in Austria was reported on 8 August at 40.5°C. In Güssing, which is located within the project area, 40.0 °C were recorded. In the lower reaches of the river Pinka, at the station Burg the monthly mean water temperature of August 2013 was with more than 22°C, 1°C higher than the mean water temperature of the same period of the previous years. At the same station, the maximum water temperature of 27.1°C was recorded on 29 July, 9 days prior to the air temperature record. Analysis shows that at the downstream stations the main driving parameter is solar radiation whereas at the upstream stations a better correlation between air temperature and water temperature is obtained. Using the extensive data set

  12. Long-term changes in sea surface temperatures

    International Nuclear Information System (INIS)

    Historical observations of sea surface temperature since 1856 have been improved by applying corrections to compensate for the predominant use of uninsulated or partly insulated buckets until the Second World War. There are large gaps in coverage in the late nineteenth century and around the two world wars, but a range of statistical techniques suggest that these gaps do not severely prejudice estimates of global and regional climatic change. Nonetheless, to improve the analysis on smaller scales, many unused historical data are to be digitized and incorporated. For recent years, satellite-based sea surface temperatures have improved the coverage, after adjustments for their biases relative to in situ data. An initial version of a nominally globally complete sea ice and interpolated sea surface temperature data set, beginning in 1871, has been created for use in numerical simulations of recent climate. Long time series of corrected regional, hemispheric, and global sea surface temperatures are mostly consistent with corresponding night marine air temperature series, and confirm the regionally specific climatic changes portrayed in the Scientific Assessments of the intergovernmental Panel on Climate Change. The observations also show an El Nino-like oscillation on bidecadal and longer time scales

  13. Effect of green roofs on air temperature; measurement study of well-watered and dry conditions

    Science.gov (United States)

    Solcerova, Anna; van de Ven, Frans; Wang, Mengyu; van de Giesen, Nick

    2016-04-01

    Rapid urbanization and increasing number and duration of heat waves poses a need for understanding urban climate and ways to mitigate extremely high temperatures. One of repeatedly suggested and often investigated methods to moderate the so called urban heat island are green roofs. This study investigates several extensive green roofs in Utrecht (NL) and their effect on air temperature right above the roof surface. Air temperature was measured 15 and 30 cm above the roof surface and also in the substrate. We show that under normal condition is air above green roof, compared to white gravel roof, colder at night and warmer during day. This suggest that green roofs might help decrease air temperatures at night, when the urban heat island is strongest, but possibly contribute to high temperatures during daytime. We also measured situation when the green roofs wilted and dried out. Under such conditions green roof exhibits more similar behavior to conventional white gravel roof. Interestingly, pattern of soil temperature remains almost the same for both dry and well-prospering green roof, colder during day and warmer at night. As such, green roof works as a buffer of diurnal temperature changes.

  14. LONG TERM VARIATION OF AIR TEMPERATURE IN THE SIRET CORRIDOR

    Directory of Open Access Journals (Sweden)

    Lucian Sfîcă

    2011-10-01

    Full Text Available This study, supported by the analysis of data from meteorological stations located in the Siret Corridor, confirms the trend of the increase in air temperature in Romania. This increase is statistically proven by the analysis of a series of observations of mean air temperature in Roman, where the increase has been 0.88°C in the last century. Using the Fourier analysis, we could highlight the influence of several factors in the evolution of air temperature in the area studied. Amongst these, the most obvious ones were the biannual oscillation (which translates into alternating between 2 – 3 warm years with 2 – 3 colder years, the North Atlantic oscillation (7 – 8 years cycle, as well as lunar and solar cycles.

  15. AMBIENT AIR TEMPERATURE EFFECT ON POWER PLANT PERFORMANCE

    OpenAIRE

    Rajesh. Kumar; Sarabpreet Singh

    2012-01-01

    The performance of the power plant strongly depends on ambient air temperature (AAT).Mass flow rate (kg/s)of air decreases in summer with increasing AAT for the same volumetric flow rate (m3/s), which results in reduced power output of turbine and increased heat rate.This paper analyzes the effects of the AAT on various parameters of power plant viz., mass flow rate of air, fuel consumption, steam, power output of turbine, efficiency and heat rate of gas turbine, steam turbine and combined cy...

  16. DISAGGREGATION OF GOES LAND SURFACE TEMPERATURES USING SURFACE EMISSIVITY

    Science.gov (United States)

    Accurate temporal and spatial estimation of land surface temperatures (LST) is important for modeling the hydrological cycle at field to global scales because LSTs can improve estimates of soil moisture and evapotranspiration. Using remote sensing satellites, accurate LSTs could be routine, but unfo...

  17. Plutonium isotopes in the surface air in Japan

    International Nuclear Information System (INIS)

    Plutonium isotope concentrations in the surface air at Tsukuba, Japan are reported during the period from 1981 to the end of 1986. The 239,240Pu concentration in the surface air, which showed a marked seasonal variation with a spring maximum and fall minimum, decreased until the end of 1985 according to the stratospheric residence time of 1.15 years. In May 1986, elevated 239,240Pu concentrations with high 238Pu/239,240Pu activity ratios were observed. The serial trend of plutonium concentration in the surface air is similar to the concentrations of the Chernobyl-released radionuclides. These findings suggest that a significant part of the plutonium in the surface air in May 1986 was due to the Chernobyl fallout. (author) 15 refs.; 2 figs.; 3 tabs

  18. Trends in Surface Temperature at High Latitudes

    Science.gov (United States)

    Comiso, Josefino C.

    2012-01-01

    The earliest signal of a climate change is expected to be found in the polar regions where warming is expected to be amplified on account of ice-albedo feedbacks associated with the high reflectivity of snow and ice. Because of general inaccessibility, there is a general paucity of in situ data and hence the need to use satellite data to observe the large-scale variability and trends in surface temperature in the region. Among the most important sensors for monitoring surface temperature has been the Advanced Very High Resolution Radiometer (AVHRR) which was first launched in 1978 and has provided continuous thermal infrared data since 1981. The top of the atmosphere data are converted to surface temperature data through various schemes that accounts for the unique atmospheric and surface conditions in the polar regions. Among the highest source of error in the data is cloud masking which is made more difficult in the polar region because of similar Signatures of clouds and snow lice covered areas. The availability of many more channels in the Moderate Resolution Imaging Spectroradiometer (MODIS) launched on board Terra satellite in December 1999 and on board Aqua in May 2002 (e.g., 36 visible and infrared channels compared to 5 for AVHRR) made it possible to minimize the error. Further capabilities were introduced with the Advanced Microwave Scanning Radiometer (AMSR) which has the appropriate frequency channels for the retrieval of sea surface temperature (SST). The results of analysis of the data show an amplified warming in the Arctic region, compared with global warming. The spatial distribution of warming is, however, not uniform and during the last 3 decades, positive temperature anomalies have been most pronounced in North America, Greenland and the Arctic basin. Some regions of the Arctic such as Siberia and the Bering Sea surprisingly show moderate cooling but this may be because these regions were anomalously warm in the 1980s when the satellite record

  19. Global climate models’ bias in surface temperature trends and variability

    International Nuclear Information System (INIS)

    The Earth has warmed in the last century with the most rapid warming occurring near the surface in the Arctic. This Arctic amplification occurs partly because the extra heat is trapped in a thin layer of air near the surface due to the persistent stable-stratification found in this region. The amount of warming depends upon the extent of turbulent mixing in the atmosphere, which is described by the depth of the atmospheric boundary layer (ABL). Global climate models (GCMs) tend to over-estimate the depth of stably-stratified ABLs, and here we show that GCM biases in the ABL depth are strongly correlated with biases in the surface temperature variability. This highlights the need for a better description of the stably-stratified ABL in GCMs in order to constrain the current uncertainty in climate variability and projections of climate change in the surface layer. (letter)

  20. Dissolved air flotation of surface water for spiral-wound module nanofiltration pre-treatment

    OpenAIRE

    Geraldes, Vitor; Anil, Aykut; de Pinho, Maria Norberta; duarte, elizabeth

    2008-01-01

    Bench-scale dissolved air flotation (DAF) of Tagus River surface water (Valadas, Portugal) was investigated as pre-treatment for spiral-wound module nanofiltration (SWNF). Before the DAF, a coagulation/flocculation of the surface water was performed using aluminium sulphate, ferric chloride and chitosan coagulants and several commercial coagulant aids. The coagulation/flocculation experiments were carried with 2 L of surface water in a jartest equipment at room temperature. The DA...

  1. Effects of air flow directions on composting process temperature profile

    International Nuclear Information System (INIS)

    In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO2 and O2 ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2

  2. Distributed modeling of monthly air temperatures over the rugged terrain of the Yellow River Basin

    Institute of Scientific and Technical Information of China (English)

    ZENG Yan; QIU XinFa; HE YongJian; SHI GuoPing; LIU ChangMing

    2009-01-01

    Our analyses of the monthly mean air temperature of meteorological stations show that altitude, global solar radiation and surface effective radiation have a significant impact on air temperature. We set up a physically-based empirical model for monthly air temperature simulation. Combined the proposed model with the distributed modeling results of global solar radiation and routine meteorological ob-servation data, we also developed a method for the distributed simulation of monthly sir temperatures over rugged terrain. Spatial distribution maps are generated at a resolution of 1 km×1 km for the monthly mean, the monthly mean maximum and the monthly mean minimum air temperatures for the Yellow River Basin. Analysis shows that the simulation results reflect to a considerable extent the macro and local distribution characteristics of air temperature. Cross-validation shows that the pro-posed model displays good stability with mean absolute bias errors of 0.19℃-0.35℃. Tests carried out on local meteorological station data and case year data show that the model has good spatial and temporal simulation capacity. The proposed model solely uses routine meteorological data and can be applied easily to other regions.

  3. Basement Kind Effects on Air Temperature of a Solar Chimney in Baghdad - Iraq Weather

    Directory of Open Access Journals (Sweden)

    Miqdam Tariq Chaichan

    2011-01-01

    Full Text Available A solar updraft tower power plant (solar tower is a solar thermal power plant that utilizes a combination of solar air collector and central updraft tube to generate an induced convective flow which drives pressure staged turbines to generate electricity. This paper presents practical results of a prototype of a solar chimney with thermal mass, where the glass surface is replaced by transparence plastic cover. The study focused on chimney's basements kind effect on collected air temperatures. Three basements were used: concrete, black concrete and black pebbles basements. The study was conducted in Baghdad from August to November 2009. The results show that the best chimney efficiency attained was 49.7% for pebbles base. The highest collected air temperature reached was 49ºC when using the black pebbles basement also.also, the maximum basement temperature measured was 59ºC for black pebbles. High increaments in collected air temperatures were achieved in comparison with the ambient air temperatures for the three basement kinds. The highest temperature difference reached was 22ºC with the pebble ground.

  4. Growth of oriented crystalline Ag nanoislands on air-exposed Si(0 0 1) surfaces

    International Nuclear Information System (INIS)

    Growth of Ag islands under ultrahigh vacuum condition on air-exposed Si(0 0 1)-(2 x 1) surfaces has been investigated by in-situ reflection high energy electron diffraction (RHEED). A thin oxide is formed on Si via exposure of the clean Si(0 0 1)-(2 x 1) surface to air. Deposition of Ag on this oxidized surface was carried out at different substrate temperatures. Deposition at room temperature leads to the growth of randomly oriented Ag islands while well-oriented Ag islands, with (0 0 1)Ag||(0 0 1)Si, [1 1 0]Ag||[1 1 0]Si, have been found to grow at substrate temperatures of ≥350 deg. C in spite of the presence of the oxide layer between Ag islands and Si. The RHEED patterns show similarities with the case of Ag deposition on H-passivated Si(0 0 1) surfaces.

  5. Concentration of 7Be in surface air at Suva, Fiji

    International Nuclear Information System (INIS)

    A high-volume air sampler and a high-resolution gamma-ray spectrometer have been in use since August 1997 at the University of the South Pacific to measure the activity of 7Be in surface air at Suva, the capital city of Fiji. Preliminary measurements during August-November 1997 indicate that the average concentration of 7Be in surface air is approximately 4.0 mBq m-3. Further measurements are in progress. (author). 4 refs., 1 fig

  6. Weed emergence as influenced by soil moisture and air temperature

    OpenAIRE

    Calado, José; G. Basch; Carvalho, Mário

    2009-01-01

    Abstract Emergence of weed seedlings depends on soil environmental conditions; mainly temperature and moisture, with the latter being fundamental and particularly important in environments which are characterised by irregular amounts and distribution of rainfall throughout the year. Thus, this study looks at the influence of soil moisture and air temperature on the emergence of weed seedlings. The experiment was carried out under controlled environmental conditions, using rings filled with s...

  7. Mean annual air temperature; 1 : 2 000 000

    International Nuclear Information System (INIS)

    Air temperature is one of the most important climate-forming factors. It shows the close dependence on the sea level altitude and the geographical latitude. The mean annual temperatures then characterise the sea level altitude of the particular locality and the dependence on the geographical latitude. This is why the warmest spots of Slovakia are situated in the south of the Podunajska nizina Lowland and the coldest are to be found on the peaks of the Vysoke Tatry Mts. (authors)

  8. The Effects of Air Pollution and Temperature on COPD.

    Science.gov (United States)

    Hansel, Nadia N; McCormack, Meredith C; Kim, Victor

    2016-06-01

    Chronic Obstructive Pulmonary Disease (COPD) affects 12-16 million people in the United States and is the third-leading cause of death. In developed countries, smoking is the greatest risk factor for the development of COPD, but other exposures also contribute to the development and progression of the disease. Several studies suggest, though are not definitive, that outdoor air pollution exposure is linked to the prevalence and incidence of COPD. Among individuals with COPD, outdoor air pollutants are associated with loss of lung function and increased respiratory symptoms. In addition, outdoor air pollutants are also associated with COPD exacerbations and mortality. There is much less evidence for the impact of indoor air on COPD, especially in developed countries in residences without biomass exposure. The limited existing data suggests that indoor particulate matter and nitrogen dioxide concentrations are linked to increased respiratory symptoms among patients with COPD. In addition, with the projected increases in temperature and extreme weather events in the context of climate change there has been increased attention to the effects of heat exposure. Extremes of temperature-both heat and cold-have been associated with increased respiratory morbidity in COPD. Some studies also suggest that temperature may modify the effect of pollution exposure and though results are not conclusive, understanding factors that may modify susceptibility to air pollution in patients with COPD is of utmost importance. PMID:26683097

  9. Temperature effect on the creep behavior of alloy 617 in air and helium environments

    International Nuclear Information System (INIS)

    The temperature effect on creep and oxidation behaviors in air and helium (He) environments was investigated at 950, 900 and 850 °C for Alloy 617, which is considered as a prime candidate material for VHTR components. Creep data were obtained with different stress levels at the three temperatures. Oxidation microstructural features such as the surface oxide layer, internal oxidation and decarburization were analyzed by observing each crept specimen. At 950 and 900 °C, the creep rupture time in He environment was shorter than that in air, and the thickness of the surface oxide layer was thicker than in air. The deterioration of creep resistance in the He environment was due to a thicker oxide-layer thickness, which reduced the effective area carrying the creep load. On the other hand, at 850 °C, the creep rupture time was almost the same regardless of both environments. The surface oxide-layer thickness was reduced by about 50% compared to the temperatures of 950 and 900 °C. The temperature of 850 °C could be assumed as a boundary temperature at which the He effects disappeared. It was found that the relationship between the creep data and surface oxide-layer thickness was in accordance with both environments

  10. Tritiated water vapor in the surface air at Tokyo

    International Nuclear Information System (INIS)

    Tritium concentration in water vapor in the air near the surface and in the precipitation at Tokyo was measured during the period from 9 August to 20 November in 1974. From August to the middle of October, tritium mixing ratios in the surface air had relatively higher values except those in air masses which were associated with a typhoon. The mixing ratios of tritium in the air decreased abruptly at the middle of October, which indicates the decrease of tritium influx from aloft. These data exhibit the salient feature that variations in tritium concentration in TR are linear to the reciprocal of the content of water vapor during each period. Tritium concentrations in vapor and rain water collected simultaneously show nearly equal values. One of the reasons for the good correlation of tritium concentration between falling drops and ambient air is considered to be the result of the rapid isotopic exchange. (author)

  11. INTRA URBAN AIR TEMPERATURE DISTRIBUTIONS IN HISTORIC URBAN CENTER

    Directory of Open Access Journals (Sweden)

    Elmira Jamei

    2012-01-01

    Full Text Available The study investigates the urban heat island effect in Malaysian historic town Malacca through seven mobile traverses, as carried out on 10 December 2011. It aims to identify the intra-urban air temperature differences between heritage core zone, new development area and outskirts of the city. Air temperature variations were also analyzed across three different zones; namely the outskirts, the heritage site and the city center district. Heat index values were then calculated based on air temperature and relative humidity to gauge the level of outdoor thermal comfort within the study area. Based on the indications, one may conclude that the heritage place’s core zone is currently threatened by escalating temperatures and that its current temperature range falls within the “caution” and “extreme caution” categories. Furthermore, no significant difference was observed between the peak temperatures of the old city quarters and newer areas; despite the disparities in their urban forms. Therefore, it is hoped that the study, with its implications, will be able to influence future environmental consideration in heritage city of Melaka.

  12. Potential vorticity intrusion index and climate variability of surface temperature

    Science.gov (United States)

    Cai, M.

    2003-04-01

    This paper proposes a potential vorticity intrusion index (denoted as PVI) as an alternative diagnostic tool to study the observed climate variability/trend of the surface temperature. The PVI index is defined as the percentage area of upper lever PV intrusion in the extratropics at any given time. Abundance (shortage) of extreme cold surface air temperature episodes in high latitudes coincides with a high (low) PVI index. The interannual variability of the PVI index exhibits a strong QBO- like signal. The high (low) PVI index prevails when the equatorial zonal mean zonal wind at 50 hPa is easterly (westerly). The probability distribution map of PV intrusion activities shows a shift of the preferred regions of frontogenesis from the oceans to the continents when the PVI index is high. This explains directly why more extreme cold events are observed over the northern Eurasian and Northern America continents when the PVI index is high or the QBO is in the easterly phase.

  13. Reintroducing radiometric surface temperature into the Penman-Monteith formulation

    Science.gov (United States)

    Mallick, Kaniska; Boegh, Eva; Trebs, Ivonne; Alfieri, Joseph G.; Kustas, William P.; Prueger, John H.; Niyogi, Dev; Das, Narendra; Drewry, Darren T.; Hoffmann, Lucien; Jarvis, Andrew J.

    2015-08-01

    Here we demonstrate a novel method to physically integrate radiometric surface temperature (TR) into the Penman-Monteith (PM) formulation for estimating the terrestrial sensible and latent heat fluxes (H and λE) in the framework of a modified Surface Temperature Initiated Closure (STIC). It combines TR data with standard energy balance closure models for deriving a hybrid scheme that does not require parameterization of the surface (or stomatal) and aerodynamic conductances (gS and gB). STIC is formed by the simultaneous solution of four state equations and it uses TR as an additional data source for retrieving the "near surface" moisture availability (M) and the Priestley-Taylor coefficient (α). The performance of STIC is tested using high-temporal resolution TR observations collected from different international surface energy flux experiments in conjunction with corresponding net radiation (RN), ground heat flux (G), air temperature (TA), and relative humidity (RH) measurements. A comparison of the STIC outputs with the eddy covariance measurements of λE and H revealed RMSDs of 7-16% and 40-74% in half-hourly λE and H estimates. These statistics were 5-13% and 10-44% in daily λE and H. The errors and uncertainties in both surface fluxes are comparable to the models that typically use land surface parameterizations for determining the unobserved components (gS and gB) of the surface energy balance models. However, the scheme is simpler, has the capabilities for generating spatially explicit surface energy fluxes and independent of submodels for boundary layer developments. This article was corrected on 27 AUG 2015. See the end of the full text for details.

  14. The effect of grass transpiration on the air temperature

    Czech Academy of Sciences Publication Activity Database

    Šír, M.; Tesař, Miroslav; Lichner, Ľ.; Czachor, H.

    2014-01-01

    Roč. 69, č. 11 (2014), s. 1570-1576. ISSN 0006-3088 Institutional support: RVO:67985874 Keywords : air temperature oscillations * embolism * plant transpiration * soil water * tensiometric pressure * xylem tension Subject RIV: DA - Hydrology ; Limnology Impact factor: 0.827, year: 2014

  15. High surface area carbon for bifunctional air electrodes applied in zinc-air batteries

    Energy Technology Data Exchange (ETDEWEB)

    Arai, H. [on leave from NTT Laboratories (Japan); Mueller, S.; Haas, O. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Bifunctional air electrodes with high surface area carbon substrates showed low reduction overpotential, thus are promising for enhancing the energy efficiency and power capability of zinc-air batteries. The improved performance is attributed to lower overpotential due to diffusion of the reaction intermediate, namely the peroxide ion. (author) 1 fig., 2 refs.

  16. Air temperature estimation with MSG-SEVIRI data: Calibration and validation of the TVX algorithm for the Iberian Peninsula

    DEFF Research Database (Denmark)

    Nieto Solana, Hector; Sandholt, Inge; Aguado, Inmaculada; Chuvieco, Emilio; Stisen, Simon

    2011-01-01

    Air temperature can be estimated from remote sensing by combining information in thermal infrared and optical wavelengths. The empirical TVX algorithm is based on an estimated linear relationship between observed Land Surface Temperature (LST) and a Spectral Vegetation Index (NDVI). Air temperature...... variation in NDVI of the effective full cover has not been subject for investigation. The present study proposes a novel methodology to estimate NDVImax that uses observed air temperature to calibrate the NDVImax for each vegetation type. To assess the validity of this methodology, we have compared the...

  17. Effect of machining on the deformability of steel in surface-active medium at lower temperatures

    International Nuclear Information System (INIS)

    The effect of some machining methods of carbon steel, chromium steel, and chromium nickel steel, and that of low temperatures on the principle characteristics of formability during impact bending in air and a surface-active environment have been studied. The temperature decrease from the ambient to -80 deg is shown to reduce steel formability as evaluated by deflection (f) and to increase the forming force. The variation of these characteristics with lowering temperature, however, is greatly affected by machining process conditions. The FRHT (Friction-Hardening Treatment) on the white layer assures minimum ductility losses, and increases steel strength at low temperatures both in air and in the surface-active environment

  18. Influence of the Spring Arctic Oscillation on Midsummer Surface Air Temperature over the Yangtze River Valley%春季北极涛动对盛夏长江流域地表气温的影响

    Institute of Scientific and Technical Information of China (English)

    张乐英; 徐海明; 施宁

    2015-01-01

    本文基于1958至2002年的ERA-40月平均再分析资料,利用年际增量方法分析了春季北极涛动(Arctic Oscillation,简称AO)与我国夏季长江流域地表气温的关系。结果表明,在扣除前期冬季ENSO影响后,5月AO指数与8月长江流域地表气温存在显著正相关。通过回归分析发现,5月AO可通过影响中低纬度的海气相互作用进而影响8月长江流域地表气温。当5月AO处于正位相时,在(10°~15°N)及赤道附近产生异常下沉气流,对应着西太平洋局地Hadley环流减弱,对流层底层出现了异常的反气旋性辐散气流。与之对应,赤道西太平洋地区出现了显著的东风异常。由于该东风异常位于5月气候平均的局地海表面温度(SST)极大值中心位置上,该东风异常可通过平流作用使得高海温不断地向西堆积,最终造成赤道西太平洋SST出现显著正异常。当该SST正异常持续至8月时,它通过 Gill 响应(Gill,1980)在其西北侧激发出气旋性异常环流,它有利于西太平洋副热带高压在我国长江流域的维持,进而造成长江流域地表气温正异常。反之,则相反。%AbstractBased on ERA-40 monthly mean reanalysis data over the period 1958–2002, this paper studies the relationship between the spring Arctic Oscillation (AO) and the summer surface air temperature (SAT) over the Yangtze River valley by adopting the year-to-year increment approach. The winter ENSO signal is filtered out in advance. Results show that the AO in May is significantly and positively correlated with the SAT over the Yangtze River valley in August. The possible physical mechanism for this relationship is investigated by means of regression analysis. The air–ocean interaction over the middle and low latitudes might play an important role. Following a stronger positive AO in May, an anomalous subsidence flow appears over the region 10°–15°N and the Equator

  19. High-Temperature Oxide Regrowth on Mechanically-Damaged Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL; Lowe, Tracie M [ORNL

    2008-01-01

    Here we report the effects of mechanical damage from a sharp stylus on the regrowth of oxide layers on a Ni-based superalloy known as Pyromet 80A . It was found that the oxide that reformed on the damaged portion of a pre-oxidized surface differed from that which formed on undamaged areas after the equal exposures to elevated temperature in air. These findings have broad implications for modeling the processes of material degradation in applications such as exhaust valves in internal combustion engines because they imply that static oxidation data for candidate materials may not adequately reflect their reaction to operating environments that involve both mechanical contact and oxidation.

  20. The international surface temperature initiative global land surface databank: monthly temperature data release description and methods

    OpenAIRE

    Rennie, J.J.; Lawrimore, Jay; Gleason, B.E.; Thorne, Peter; Morice, C. P.; M. J. Menne; C. N. Williams Jr.; Gambi de Almeida, W.; Christy, J.R.; Flannery, M.; Ishihara, M.; Kamiguchi, K.; Klein-Tank, A.M.G.; A. Mhanda; Lister, D. H.

    2014-01-01

    Described herein is the first version release of monthly temperature holdings of a new Global Land Surface Meteorological Databank. Organized under the auspices of the International Surface Temperature Initiative (ISTI), an international group of scientists have spent three years collating and merging data from numerous sources to create a merged holding. This release in its recommended form consists of over 30 000 individual station records, some of which extend over the past 300 years. This...

  1. Phytoclimatic assessment of air temperatures transition across important Bbundary values

    International Nuclear Information System (INIS)

    Thermal regime investigation in global and regional scale is the problem permanently in field of vision of climatologists in the world. Many of investigations abroad and in our country are devoted to discover long time variation, cycles and their periodicity and especially on the registration of air temperatures changes and averages per year, per six months, seasons and months. Great interest is assessment of change of terms for strong air temperatures transition across 0, 5, 10 and 15oC during spring and autumn seasons, because they have important scientific and practical application i.e. they are the limit between cold and warm part of the year and trace out duration of the vegetative and non vegetative for different bio ecosystems such as phyto ecosystems and zoo ecosystems. For this reason, the interest on the investigation of agro climatic and forest climatic peculiarity of these indicators increase for last few years. This increase is connected with big importance part of nature season's dynamics connected with human economic activity. Increase of air temperature up to 0oC an transition by this limit certify for change of cold with warm period and beginning of spring; Contrariwise, decrease the temperatures down the 0oC shows the end of autumn and beginning of winter. In the moderate continental climatic regions, where is classified most big part of Bulgaria territory is observed for seasons - winter, spring, summer and autumn. Climatologists usually accept these seasons with equal duration - three months. This duration of the seasons, do not permit to provide clear assessment of meteorological conditions in connection with development of plant ecosystems and production in different country regions. By this reason, seasons differentiation by agro climatic and forest-climatic point of view is other use the annual course of the air temperatures. As a strong and most suitable way for beginning and end of seasons are air temperatures transitions up and down

  2. Air pollution, temperature and pediatric influenza in Brisbane, Australia.

    Science.gov (United States)

    Xu, Zhiwei; Hu, Wenbiao; Williams, Gail; Clements, Archie C A; Kan, Haidong; Tong, Shilu

    2013-09-01

    Previous studies have demonstrated the importance of weather variables in influencing the incidence of influenza. However, the role of air pollution is often ignored in identifying the environmental drivers of influenza. This research aims to examine the impacts of air pollutants and temperature on the incidence of pediatric influenza in Brisbane, Australia. Lab-confirmed daily data on influenza counts among children aged 0-14years in Brisbane from 2001 January 1st to 2008 December 31st were retrieved from Queensland Health. Daily data on maximum and minimum temperatures for the same period were supplied by the Australian Bureau of Meteorology. Winter was chosen as the main study season due to it having the highest pediatric influenza incidence. Four Poisson log-linear regression models, with daily pediatric seasonal influenza counts as the outcome, were used to examine the impacts of air pollutants (i.e., ozone (O3), particulate matter≤10μm (PM10) and nitrogen dioxide (NO2)) and temperature (using a moving average of ten days for these variables) on pediatric influenza. The results show that mean temperature (Relative risk (RR): 0.86; 95% Confidence Interval (CI): 0.82-0.89) was negatively associated with pediatric seasonal influenza in Brisbane, and high concentrations of O3 (RR: 1.28; 95% CI: 1.25-1.31) and PM10 (RR: 1.11; 95% CI: 1.10-1.13) were associated with more pediatric influenza cases. There was a significant interaction effect (RR: 0.94; 95% CI: 0.93-0.95) between PM10 and mean temperature on pediatric influenza. Adding the interaction term between mean temperature and PM10 substantially improved the model fit. This study provides evidence that PM10 needs to be taken into account when evaluating the temperature-influenza relationship. O3 was also an important predictor, independent of temperature. PMID:23911338

  3. Spatiotemporal relationships between sea level pressure and air temperature in the tropics

    CERN Document Server

    Makarieva, Anastassia M; Nefiodov, Andrei V; Sheil, Douglas; Nobre, Antonio Donato; Li, Bai-Lian Larry

    2014-01-01

    While surface temperature gradients have been highlighted as drivers of low-level atmospheric circulation, the underlying physical mechanisms remain unclear. Lindzen and Nigam (1987) noted that sea level pressure (SLP) gradients are proportional to surface temperature gradients if isobaric height (the height where pressure does not vary in the horizontal plane) is constant; their own model of low-level circulation assumed that isobaric height in the tropics is around 3 km. Recently Bayr and Dommenget (2013) proposed a simple model of temperature-driven air redistribution from which they derived that the isobaric height in the tropics again varies little but occurs higher (at the height of the troposphere). Here investigations show that neither the empirical assumption of Lindzen and Nigam (1987) nor the theoretical derivations of Bayr and Dommenget (2013) are plausible. Observations show that isobaric height is too variable to determine a universal spatial or temporal relationship between local values of air ...

  4. Turbulent drag reduction over air- and liquid- impregnated surfaces

    Science.gov (United States)

    Rosenberg, Brian J.; Van Buren, Tyler; Fu, Matthew K.; Smits, Alexander J.

    2016-01-01

    Results on turbulent skin friction reduction over air- and liquid-impregnated surfaces are presented for aqueous Taylor-Couette flow. The surfaces are fabricated by mechanically texturing the inner cylinder and chemically modifying the features to make them either non-wetting with respect to water (air-infused, or superhydrophobic case), or wetting with respect to an oil that is immiscible with water (liquid-infused case). The drag reduction, which remains fairly constant over the Reynolds number range tested (100 ≤ Reτ ≤ 140), is approximately 10% for the superhydrophobic surface and 14% for the best liquid-infused surface. Our results suggest that liquid-infused surfaces may enable robust drag reduction in high Reynolds number turbulent flows without the shortcomings associated with conventional superhydrophobic surfaces, namely, failure under conditions of high hydrodynamic pressure and turbulent flow fluctuations.

  5. Temperature Calculation in Respect of Basic Elements of Power Oil Transformer on the Basis of Its Tank Surface Temperature Analysis

    Directory of Open Access Journals (Sweden)

    D. Zalizny

    2012-01-01

    Full Text Available The paper proposes a real-time calculation algorithm of oil, winding and magnetic core temperature of power transformer on the basis of measured values of tank surface temperature and air temperature without measuring current. The algorithm is based on the calculation of the equivalent load factor of the transformer. Imitation simulation has confirmed efficiency of the algorithm. After tests on functioning transformers the algorithm can be used in thermal protection devices and diagnostic devices for power oil transformers.

  6. Temperature Calculation in Respect of Basic Elements of Power Oil Transformer on the Basis of Its Tank Surface Temperature Analysis

    OpenAIRE

    D. Zalizny; O. Shirokov

    2012-01-01

    The paper proposes a real-time calculation algorithm of oil, winding and magnetic core temperature of power transformer on the basis of measured values of tank surface temperature and air temperature without measuring current. The algorithm is based on the calculation of the equivalent load factor of the transformer. Imitation simulation has confirmed efficiency of the algorithm. After tests on functioning transformers the algorithm can be used in thermal protection devices and diagnostic dev...

  7. Air - water temperature relationships in the trout streams of southeastern Minnesota’s carbonate - sandstone landscape

    Science.gov (United States)

    Krider, Lori A.; Magner, Joseph A.; Perry, Jim; Vondracek, Bruce C.; Ferrington, Leonard C., Jr.

    2013-01-01

    Carbonate-sandstone geology in southeastern Minnesota creates a heterogeneous landscape of springs, seeps, and sinkholes that supply groundwater into streams. Air temperatures are effective predictors of water temperature in surface-water dominated streams. However, no published work investigates the relationship between air and water temperatures in groundwater-fed streams (GWFS) across watersheds. We used simple linear regressions to examine weekly air-water temperature relationships for 40 GWFS in southeastern Minnesota. A 40-stream, composite linear regression model has a slope of 0.38, an intercept of 6.63, and R2 of 0.83. The regression models for GWFS have lower slopes and higher intercepts in comparison to surface-water dominated streams. Regression models for streams with high R2 values offer promise for use as predictive tools for future climate conditions. Climate change is expected to alter the thermal regime of groundwater-fed systems, but will do so at a slower rate than surface-water dominated systems. A regression model of intercept vs. slope can be used to identify streams for which water temperatures are more meteorologically than groundwater controlled, and thus more vulnerable to climate change. Such relationships can be used to guide restoration vs. management strategies to protect trout streams.

  8. The effects of sea surface temperature gradients on surface turbulent fluxes

    Science.gov (United States)

    Steffen, John

    A positive correlation between sea surface temperature (SST) and wind stress perturbation near strong SST gradients (DeltaSST) has been observed in different parts of the world ocean, such as the Gulf Stream in the North Atlantic and the Kuroshio Extension east of Japan. These changes in winds and SSTs can modify near-surface stability, surface stress, and latent and sensible heat fluxes. In general, these small scale processes are poorly modeled in Numerical Weather Prediction (NWP) and climate models. Failure to account for these air--sea interactions produces inaccurate values of turbulent fluxes, and therefore a misrepresentation of the energy, moisture, and momentum budgets. Our goal is to determine the change in these surface turbulent fluxes due to overlooking the correlated variability in winds, SSTs, and related variables. To model these air--sea interactions, a flux model was forced with and without SST--induced changes to the surface wind fields. The SST modification to the wind fields is based on a baroclinic argument as implemented by the University of Washington Planetary Boundary-Layer (UWPBL) model. Other input parameters include 2-m air temperature, 2-m dew point temperature, surface pressure (all from ERA--interim), and Reynolds Daily Optimum Interpolation Sea Surface Temperature (OISST). Flux model runs are performed every 6 hours starting in December 2002 and ending in November 2003. From these model outputs, seasonal, monthly, and daily means of the difference between DeltaSST and no DeltaSST effects on sensible heat flux (SHF), latent heat flux (LHF), and surface stress are calculated. Since the greatest impacts occur during the winter season, six additional December-January-February (DJF) seasons were analyzed for 1987--1990 and 1999--2002. The greatest differences in surface turbulent fluxes are concentrated near strong SST fronts associated with the Gulf Stream and Kuroshio Extension. On average, 2002---2003 DJF seasonal differences in SHF

  9. The utility of surface temperature measurements for the remote sensing of surface soil water status

    Science.gov (United States)

    Idso, S. B.; Jackson, R. D.; Reginato, R. J.; Schmugge, T. J.

    1975-01-01

    Experiments carried out on an Avondale loam soil indicated that the thermal inertia concept of soil water content detection is reasonably sound. The volumetric water contents of surface soil layers between 2 and 4 cm thick were found to be linear functions of the amplitude of the diurnal surface soil temperature wave for clear day-night periods. They were also found to be linear functions of the daily maximum value of the surface soil-air-temperature differential. Tests on three additional soils ranging from sandy loam to clay indicated that the relations determined for Avondale loam could not be accurately applied to these other soil types. When the moisture characteristic curves of each soil were used to transform water contents into pressure potentials, however, it was found that soil water pressure potential could be determined without prior knowledge of soil type, and thus its value as a potential soil water status survey tool was significantly enhanced.

  10. The EUSTACE break-detection algorithm for a global air temperature dataset

    Science.gov (United States)

    Brugnara, Yuri; Auchmann, Renate; Brönnimann, Stefan

    2016-04-01

    EUSTACE (EU Surface Temperature for All Corners of Earth) is an EU-funded project that has started in 2015; its goal is to produce daily estimates of surface air temperature since 1850 across the globe for the first time by combining surface and satellite data using novel statistical techniques. For land surface data (LSAT), we assembled a global dataset of ca. 35000 stations where daily maximum and minimum air temperature observations are available, taking advantage of the most recent data rescue initiatives. Beside quantity, data quality also plays an important role for the success of the project; in particular, the assessment of the homogeneity of the temperature series is crucial in order to obtain a product suitable for the study of climate change. This poster describes a fully automatic state-of-the-art break-detection algorithm that we developed for the global LSAT dataset. We evaluate the performance of the method using artificial benchmarks and present various statistics related to frequency and amplitude of the inhomogeneities detected in the real data. We show in particular that long-term temperature trends calculated from raw data are more often underestimated than overestimated and that this behaviour is mostly related to inhomogeneities affecting maximum temperatures.

  11. Measuring centimeter-resolution air temperature profiles above land and water using fiber-optic Distributed Temperature Sensing

    Science.gov (United States)

    Sigmund, Armin; Pfister, Lena; Olesch, Johannes; Thomas, Christoph K.

    2016-04-01

    The precise determination of near-surface air temperature profiles is of special importance for the characterization of airflows (e.g. cold air) and the quantification of sensible heat fluxes according to the flux-gradient similarity approach. In contrast to conventional multi-sensor techniques, measuring temperature profiles using fiber-optic Distributed Temperature Sensing (DTS) provides thousands of measurements referenced to a single calibration standard at much reduced costs. The aim of this work was to enhance the vertical resolution of Raman scatter DTS measurements up to the centimeter-scale using a novel approach for atmospheric applications: the optical fiber was helically coiled around a meshed fabric. In addition to testing the new fiber geometry, we quantified the measurement uncertainty and demonstrated the benefits of the enhanced-resolution profiles. The fiber-optic cable was coiled around a hollow column consisting of white reinforcing fabric supported by plexiglass rings every meter. Data from two columns of this type were collected for 47 days to measure air temperature vertically over 3.0 and 5.1 m over a gently inclined meadow and over and in a small lake, respectively. Both profiles had a vertical resolution of 1 cm in the lower section near the surface and 5 cm in the upper section with an along-fiber instrument-specific averaging of 1.0 m and a temporal resolution of 30 s. Measurement uncertainties, especially from conduction between reinforcing fabric and fiber-optic cable, were estimated by modeling the fiber temperature via a detailed energy balance approach. Air temperature, wind velocity and radiation components were needed as input data and measured separately. The temperature profiles revealed valuable details, especially in the lowest 1 m above surface. This was best demonstrated for nighttime observations when artefacts due to solar heating did not occur. For example, the dynamics of a cold air layer was detected in a clear night

  12. Can air temperature be used to project influences of climate change on stream temperature?

    International Nuclear Information System (INIS)

    Worldwide, lack of data on stream temperature has motivated the use of regression-based statistical models to predict stream temperatures based on more widely available data on air temperatures. Such models have been widely applied to project responses of stream temperatures under climate change, but the performance of these models has not been fully evaluated. To address this knowledge gap, we examined the performance of two widely used linear and nonlinear regression models that predict stream temperatures based on air temperatures. We evaluated model performance and temporal stability of model parameters in a suite of regulated and unregulated streams with 11–44 years of stream temperature data. Although such models may have validity when predicting stream temperatures within the span of time that corresponds to the data used to develop them, model predictions did not transfer well to other time periods. Validation of model predictions of most recent stream temperatures, based on air temperature–stream temperature relationships from previous time periods often showed poor performance when compared with observed stream temperatures. Overall, model predictions were less robust in regulated streams and they frequently failed in detecting the coldest and warmest temperatures within all sites. In many cases, the magnitude of errors in these predictions falls within a range that equals or exceeds the magnitude of future projections of climate-related changes in stream temperatures reported for the region we studied (between 0.5 and 3.0 °C by 2080). The limited ability of regression-based statistical models to accurately project stream temperatures over time likely stems from the fact that underlying processes at play, namely the heat budgets of air and water, are distinctive in each medium and vary among localities and through time. (letter)

  13. Simulation of air and ground temperatures in PMIP3/CMIP5 last millennium simulations: implications for climate reconstructions from borehole temperature profiles

    Science.gov (United States)

    García-García, A.; Cuesta-Valero, F. J.; Beltrami, H.; Smerdon, J. E.

    2016-04-01

    For climate models to simulate the continental energy storage of the Earth’s energy budget they must capture the processes that partition energy across the land-atmosphere boundary. We evaluate herein the thermal consequences of these processes as simulated by models in the third phase of the paleoclimate modelling intercomparison project and the fifth phase of the coupled model intercomparison project (PMIP3/CMIP5). We examine air and ground temperature tracking at decadal and centennial time-scales within PMIP3 last-millennium simulations concatenated to historical simulations from the CMIP5 archive. We find a strong coupling between air and ground temperatures during the summer from 850 to 2005 CE. During the winter, the insulating effect of snow and latent heat exchanges produce a decoupling between the two temperatures in the northern high latitudes. Additionally, we use the simulated ground surface temperatures as an upper boundary condition to drive a one-dimensional conductive model in order to derive synthetic temperature-depth profiles for each PMIP3/CMIP5 simulation. Inversion of these subsurface profiles yields temperature trends that retain the low-frequency variations in surface air temperatures over the last millennium for all the PMIP3/CMIP5 simulations regardless of the presence of seasonal decoupling in the simulations. These results demonstrate the robustness of surface temperature reconstructions from terrestrial borehole data and their interpretation as indicators of past surface air temperature trends and continental energy storage.

  14. Persistence analysis of daily mean air temperature variation in Georgia

    Science.gov (United States)

    Matcharashvili, Teimuraz; Chelidze, Tamaz; Zhukova, Natalia; Mepharidze, Ekaterine; Sborshchikov, Alexander

    2010-05-01

    Extrapolation of observed linear trends is common practice in climate change researches on different scales. In this respect it is important, that though global warming is well established, the question of persistence of trends on regional scales remain controversial. Indeed, climate change for specific region and time by definition includes more than the simple average of weather conditions. Either random events or long-term changes, or more often combinations of them, can bring about significant swings in a variety of climate indicators from one time period to the next. Therefore in order to achieve further understanding of dynamics of climate change the character of stable peculiarities of analyzed dynamics should be investigated. Analysis of the character of long range correlations in climatological time series or peculiarities of their inherent memory is motivated exactly by this goal. Such analysis carried out on a different scales may help to understand spatial and temporal features of regional climate change. In present work the problem of persistence of observed trends in air temperature time series in Georgia was investigated. Longest available mean daily temperature time series of Tbilisi (1890-2008) were analyzed. Time series on shorter time scales of five stations in the West and East Georgia also were considered as well as monthly mean temperature time series of five stations. Additionally, temporally and spatially averaged daily and monthly mean air temperature time series were analyzed. Extent of persistence in mentioned time series were evaluated using R/S analysis calculation. Detrended and Multifractal Detrended Fluctuation Analysis as well as multi scaling analysis based on CWT have been used. Our results indicate that variation of daily or monthly mean temperatures reveals clear antipersistence on whole available time scale. It seems that antipersistence on global scale is general characteristics of mean air temperature variation and is not

  15. Estimating minimum and maximum air temperature using MODIS data over Indo-Gangetic Plain

    Indian Academy of Sciences (India)

    D B Shah; M R Pandya; H J Trivedi; A R Jani

    2013-12-01

    Spatially distributed air temperature data are required for climatological, hydrological and environmental studies. However, high spatial distribution patterns of air temperature are not available from meteorological stations due to its sparse network. The objective of this study was to estimate high spatial resolution minimum air temperature (min) and maximum air temperature (max) over the Indo-Gangetic Plain using Moderate Resolution Imaging Spectroradiometer (MODIS) data and India Meteorological Department (IMD) ground station data. min was estimated by establishing an empirical relationship between IMD min and night-time MODIS Land Surface Temperature (s). While, max was estimated using the Temperature-Vegetation Index (TVX) approach. The TVX approach is based on the linear relationship between s and Normalized Difference Vegetation Index (NDVI) data where max is estimated by extrapolating the NDVI-s regression line to maximum value of NDVImax for effective full vegetation cover. The present study also proposed a methodology to estimate NDVImax using IMD measured max for the Indo-Gangetic Plain. Comparison of MODIS estimated min with IMD measured min showed mean absolute error (MAE) of 1.73°C and a root mean square error (RMSE) of 2.2°C. Analysis in the study for max estimation showed that calibrated NDVImax performed well, with the MAE of 1.79°C and RMSE of 2.16°C.

  16. Novel solar air Heater for high temperatures; Novedoso Calentador solar de aire para altas temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Rincon, E. A.; Duran, M. D.; Lentz, A. E.

    2008-07-01

    A novel solar air heater that allows to reach temperatures of the order of 100 degree centigrade with thermal efficiencies superior to 50% due to a solar concentrator and the reduction of thermal losses from the air when circulating between the absorber and mirrors of section of circular arc, well isolated of the outside surrounding. The receiver consists of a concentrator with wedges of plastic transparency that make the function of lenses. The light refracted by the wedges enters to a series of concentrators PC type truncated optimally so that the space among them allows the positioning of the absorber, who are covered metallic segments with selective film. Its excellent performance makes ideals applications as Sauna bath, the drying at high temperature, and systems for conditioning of air. (Author)

  17. Satellite air temperature estimation for monitoring the canopy layer heat island of Milan

    DEFF Research Database (Denmark)

    Pichierri, Manuele; Bonafoni, Stefania; Biondi, Riccardo

    2012-01-01

    In this work, satellite maps of the urban heat island of Milan are produced using satellite-based infrared sensor data. For this aim, we developed suitable algorithms employing satellite brightness temperatures for the direct air temperature estimation 2 m above the surface (canopy layer), showing...... accuracies below 2K. The air temperatures measured by ground-based weather stations were properly matched with brightness temperatures observed by the Moderate-resolution Imaging Spectroradiometer (MODIS) on board of both Terra and Aqua satellites. In total, 931 daytime and nighttime scenes taken between...... 2007 and 2010 were processed. Analysis of the canopy layer heat island (CLHI) maps during summer months reveals an average heat island effect of 3–4K during nighttime (with some peaks around 5K) and a weak CLHI intensity during daytime. In addition, the satellite maps reveal a well defined island shape...

  18. Air Cooling for High Temperature Power Electronics (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Waye, S.; Musselman, M.; King, C.

    2014-09-01

    Current emphasis on developing high-temperature power electronics, including wide-bandgap materials such as silicon carbide and gallium nitride, increases the opportunity for a completely air-cooled inverter at higher powers. This removes the liquid cooling system for the inverter, saving weight and volume on the liquid-to-air heat exchanger, coolant lines, pumps, and coolant, replacing them with just a fan and air supply ducting. We investigate the potential for an air-cooled heat exchanger from a component and systems-level approach to meet specific power and power density targets. A proposed baseline air-cooled heat exchanger design that does not meet those targets was optimized using a parametric computational fluid dynamics analysis, examining the effects of heat exchanger geometry and device location, fixing the device heat dissipation and maximum junction temperature. The CFD results were extrapolated to a full inverter, including casing, capacitor, bus bar, gate driver, and control board component weights and volumes. Surrogate ducting was tested to understand the pressure drop and subsequent system parasitic load. Geometries that met targets with acceptable loads on the system were down-selected for experimentation. Nine baseline configuration modules dissipated the target heat dissipation, but fell below specific power and power density targets. Six optimized configuration modules dissipated the target heat load, exceeding the specific power and power density targets. By maintaining the same 175 degrees C maximum junction temperature, an optimized heat exchanger design and higher device heat fluxes allowed a reduction in the number of modules required, increasing specific power and power density while still maintaining the inverter power.

  19. OPTIMIZATION OF MICROWAVE AND AIR DRYING CONDITIONS OF QUINCE (CYDONIA OBLONGA, MILLER USING RESPONSE SURFACE METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Cem Baltacioglu

    2015-03-01

    Full Text Available Effects of slice thickness of quince (Cydonia oblonga Miller , microwave incident power and air drying temperature on antioxidant activity and total phenolic content of quince were investigated during drying in microwave and air drying. Optimum conditions were found to be: i for microwave drying, 285 W and 4.14 mm thick (maximum antioxidant activity and 285 W and 6.85 mm thick (maximum total phenolic content, and ii for air drying, 75 ºC and 1.2 mm thick (both maximum antioxidant activity and total phenolic content. Drying conditions were optimized by using the response surface methodology. 13 experiments were carried out considering incident microwave powers from 285 to 795 W, air temperature from 46 to 74 ºC and slice thickness from 1.2 to 6.8 mm.

  20. Sea surface temperature variability: patterns and mechanisms.

    Science.gov (United States)

    Deser, Clara; Alexander, Michael A; Xie, Shang-Ping; Phillips, Adam S

    2010-01-01

    Patterns of sea surface temperature (SST) variability on interannual and longer timescales result from a combination of atmospheric and oceanic processes. These SST anomaly patterns may be due to intrinsic modes of atmospheric circulation variability that imprint themselves upon the SST field mainly via surface energy fluxes. Examples include SST fluctuations in the Southern Ocean associated with the Southern Annular Mode, a tripolar pattern of SST anomalies in the North Atlantic associated with the North Atlantic Oscillation, and a pan-Pacific mode known as the Pacific Decadal Oscillation (with additional contributions from oceanic processes). They may also result from coupled ocean-atmosphere interactions, such as the El Niño-Southern Oscillation phenomenon in the tropical Indo-Pacific, the tropical Atlantic Niño, and the cross-equatorial meridional modes in the tropical Pacific and Atlantic. Finally, patterns of SST variability may arise from intrinsic oceanic modes, notably the Atlantic Multidecadal Oscillation. PMID:21141660

  1. A global monthly sea surface temperature climatology

    Science.gov (United States)

    Shea, Dennis J.; Trenberth, Kevin E.; Reynolds, Richard W.

    1992-01-01

    The paper presents a new global 2 deg x 2 deg monthly sea surface temperature (SST) climatology, referred here to as the Shea-Trenberth-Reynolds (STR) climatology, which was derived by modifying a 1950-1979-based SST climatology from the Climate Analysis Center (CAC), by using data from the Comprehensive Ocean-Atmosphere Data Set to improve the SST estimates in the regions of the Kuroshio and the Gulf Stream. A comparison of the STR climatology with the Alexander and Mobley SST climatology showed that the STR climatology is warmer in the Northern Hemisphere, and colder poleward of 45 deg S.

  2. Relationships of photosynthetic photon flux density, air temperature and humidity with tomato leaf diffusive conductance and temperature

    Directory of Open Access Journals (Sweden)

    Evandro Zanini Righi

    2012-06-01

    Full Text Available The objective was to study the leaf temperature (LT and leaf diffusive vapor conductance (gs responses to temperature, humidity and incident flux density of photosynthetically active photons (PPFD of tomato plants grown without water restriction in a plastic greenhouse in Santa Maria, RS, Brazil. The plants were grown in substrate and irrigated daily. The gs was measured using a steady-state null-balance porometer on the abaxial face of the leaves during the daytime. Both leaf surfaces were measured in one day. The PPFD and LT were measured using the porometer. Leaf temperature was determined using an infrared thermometer, and air temperature and humidity were measured using a thermohygrograph. The leaves on the upper layer of the plants had higher gs than the lower layer. The relationship between the gs and PPFD was different for the two layers in the plants. A consistent relationship between the gs and atmospheric water demand was observed only in the lower layer. The LT tended to be lower than the air temperature. The mean value for the gs was 2.88 times higher on the abaxial than adaxial leaf surface.

  3. Diffusion welding in air. [solid state welding of butt joint by fusion welding, surface cleaning, and heating

    Science.gov (United States)

    Moore, T. J.; Holko, K. H. (Inventor)

    1974-01-01

    Solid state welding a butt joint by fusion welding the peripheral surfaces to form a seal is described along with, autogenetically cleaning the faying or mating surfaces of the joint by heating the abutting surfaces to 1,200 C and heating to the diffusion welding temperature in air.

  4. EML Surface Air Sampling Program, 1990--1993 data

    International Nuclear Information System (INIS)

    Measurements of the concentrations of specific atmospheric radionuclides in air filter samples collected for the Environmental Measurements Laboratory's Surface Air Sampling Program (SASP) during 1990--1993, with the exception of April 1993, indicate that anthropogenic radionuclides, in both hemispheres, were at or below the lower limits of detection for the sampling and analytical techniques that were used to collect and measure them. The occasional detection of 137Cs in some air filter samples may have resulted from resuspension of previously deposited debris. Following the April 6, 1993 accident and release of radionuclides into the atmosphere at a reprocessing plant in the Tomsk-7 military nuclear complex located 16 km north of the Siberian city of Tomsk, Russia, weekly air filter samples from Barrow, Alaska; Thule, Greenland and Moosonee, Canada were selected for special analyses. The naturally occurring radioisotopes that the authors measure, 7Be and 210Pb, continue to be detected in most air filter samples. Variations in the annual mean concentrations of 7Be at many of the sites appear to result primarily from changes in the atmospheric production rate of this cosmogenic radionuclide. Short-term variations in the concentrations of 7Be and 210Pb continued to be observed at many sites at which weekly air filter samples were analyzed. The monthly gross gamma-ray activity and the monthly mean surface air concentrations of 7Be, 95Zr, 137Cs, 144Ce, and 210Pb measured at sampling sites in SASP during 1990--1993 are presented. The weekly mean surface air concentrations of 7Be, 95Zr, 137Cs, 144Ce, and 210Pb for samples collected during 1990--1993 are given for 17 sites

  5. EML Surface Air Sampling Program, 1990--1993 data

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, R.J.; Sanderson, C.G.; Kada, J.

    1995-11-01

    Measurements of the concentrations of specific atmospheric radionuclides in air filter samples collected for the Environmental Measurements Laboratory`s Surface Air Sampling Program (SASP) during 1990--1993, with the exception of April 1993, indicate that anthropogenic radionuclides, in both hemispheres, were at or below the lower limits of detection for the sampling and analytical techniques that were used to collect and measure them. The occasional detection of {sup 137}Cs in some air filter samples may have resulted from resuspension of previously deposited debris. Following the April 6, 1993 accident and release of radionuclides into the atmosphere at a reprocessing plant in the Tomsk-7 military nuclear complex located 16 km north of the Siberian city of Tomsk, Russia, weekly air filter samples from Barrow, Alaska; Thule, Greenland and Moosonee, Canada were selected for special analyses. The naturally occurring radioisotopes that the authors measure, {sup 7}Be and {sup 210}Pb, continue to be detected in most air filter samples. Variations in the annual mean concentrations of {sup 7}Be at many of the sites appear to result primarily from changes in the atmospheric production rate of this cosmogenic radionuclide. Short-term variations in the concentrations of {sup 7}Be and {sup 210}Pb continued to be observed at many sites at which weekly air filter samples were analyzed. The monthly gross gamma-ray activity and the monthly mean surface air concentrations of {sup 7}Be, {sup 95}Zr, {sup 137}Cs, {sup 144}Ce, and {sup 210}Pb measured at sampling sites in SASP during 1990--1993 are presented. The weekly mean surface air concentrations of {sup 7}Be, {sup 95}Zr, {sup 137}Cs, {sup 144}Ce, and {sup 210}Pb for samples collected during 1990--1993 are given for 17 sites.

  6. The nature of the air-cleaved mica surface

    Science.gov (United States)

    Christenson, Hugo K.; Thomson, Neil H.

    2016-06-01

    The accepted image of muscovite mica is that of an inert and atomically smooth surface, easily prepared by cleavage in an ambient atmosphere. Consequently, mica is extensively used a model substrate in many fundamental studies of surface phenomena and as a substrate for AFM imaging of biomolecules. In this review we present evidence from the literature that the above picture is not quite correct. The mica used in experimental work is almost invariably cleaved in laboratory air, where a reaction between the mica surface, atmospheric CO2 and water occurs immediately after cleavage. The evidence suggests very strongly that as a result the mica surface becomes covered by up to one formula unit of K2CO3 per nm2, which is mobile under humid conditions, and crystallises under drier conditions. The properties of mica in air or water vapour cannot be fully understood without reference to the surface K2CO3, and many studies of the structure of adsorbed water on mica surfaces may need to be revisited. With this new insight, however, the air-cleaved mica should provide exciting opportunities to study phenomena such as two-dimensional ion diffusion, electrolyte effects on surface conductivity, and two-dimensional crystal nucleation.

  7. Modern average global sea-surface temperature

    Science.gov (United States)

    Schweitzer, Peter N.

    1993-01-01

    The data contained in this data set are derived from the NOAA Advanced Very High Resolution Radiometer Multichannel Sea Surface Temperature data (AVHRR MCSST), which are obtainable from the Distributed Active Archive Center at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif. The JPL tapes contain weekly images of SST from October 1981 through December 1990 in nine regions of the world ocean: North Atlantic, Eastern North Atlantic, South Atlantic, Agulhas, Indian, Southeast Pacific, Southwest Pacific, Northeast Pacific, and Northwest Pacific. This data set represents the results of calculations carried out on the NOAA data and also contains the source code of the programs that made the calculations. The objective was to derive the average sea-surface temperature of each month and week throughout the whole 10-year series, meaning, for example, that data from January of each year would be averaged together. The result is 12 monthly and 52 weekly images for each of the oceanic regions. Averaging the images in this way tends to reduce the number of grid cells that lack valid data and to suppress interannual variability.

  8. Using NOAA-AVHRR estimates of land surface temperature for regional agrometeorogical modelling

    Science.gov (United States)

    de Wit, A. J. W.; Boogaard, H. L.; van Diepen, C. A.

    2004-09-01

    Agrometeorological crop simulation models are used increasingly in spatial applications like regional crop monitoring and yield forecasting. The spatial application of these models involves gathering spatially representative values of meteorological input variables (temperature, radiation and precipitation). This is usually accomplished by interpolating meteorological variables measured at point locations. This paper explores the use of advanced very high resolution radiometer (AVHRR)-derived surface temperature as a replacement for interpolated maximum air temperature in a spatial crop monitoring and yield forecasting system. A 2-year set of daily National Oceanic And Atmospheric Administration (NOAA)-AVHRR images over western Europe was used to derive estimates of daily surface temperature aggregated over 50 km × 50 km gridcells, a land cover database was used to select only pixels that were classified as 'arable land'. On days that did not yield data due to cloud cover, the monthly average surface temperature was substituted. The AVHRR-derived surface temperature is usually higher than the maximum air temperature measured at a weather station. To account for this difference, an empirical model was used that relates surface temperature to maximum air temperature. The model parameters were obtained using calibration with the maximum air temperature measured at five weather stations. Next, it was applied to the entire AVHRR data set in order to convert AVHRR surface temperature into a simulated maximum air temperature. Finally, a case study was carried out by using the WOrld FOod Studies (WOFOST) crop model to simulate growth of winter-wheat and sunflower for Spain using both the simulated maximum air temperature and the interpolated maximum air temperature from weather stations. Our results demonstrate that the spatial patterns of the yearly temperature sums over Spain are similar for both sources of temperature. Therefore, it can be concluded that the AVHRR

  9. Acoustic tomographic imaging of temperature and flow fields in air

    International Nuclear Information System (INIS)

    Acoustic travel-time tomography is a remote sensing technique that uses the dependence of sound speed in air on temperature and wind speed along the sound propagation path. Travel-time measurements of acoustic signals between several sound sources and receivers travelling along different paths through a measuring area give information on the spatial distribution of temperature and flow fields within the area. After a separation of the two influences, distributions of temperature and flow can be reconstructed using inverse algorithms. As a remote sensing method, one advantage of acoustic travel-time tomography is its ability to measure temperature and flow field quantities without disturbing the area under investigation due to insertion of sensors. Furthermore, the two quantities—temperature and flow velocity—can be recorded simultaneously with this measurement method. In this paper, an acoustic tomographic measurement system is introduced which is capable of resolving three-dimensional distributions of temperature and flow fields in air within a certain volume (1.3 m × 1.0 m × 1.2 m) using 16 acoustic transmitter–receiver pairs. First, algorithms for the 3D reconstruction of distributions from line-integrated measurements are presented. Moreover, a measuring apparatus is introduced which is suited for educational purposes, for demonstration of the method as well as for indoor investigations. Example measurements within a low-speed wind tunnel with different incident flow situations (e.g. behind bluff bodies) using this system are shown. Visualizations of the flow illustrate the plausibility of the tomographically reconstructed flow structures. Furthermore, alternative individual measurement methods for temperature and flow speed provide comparable results

  10. Short-term air temperature on a regional scale and its estimation with a nocturnal cooling model

    International Nuclear Information System (INIS)

    Accuracy of spatial estimation of air temperatures can be very poor for a short term temperature. The objective of this paper is to study feasibility of the regional estimation of air temperatures with a nocturnal cooling model, which was proposed by Kondo & Mori (1982) to describe nocturnal cooling rate with wind speed and site-specific parameters. First, relationships between elevation and air temperatures within diurnal cycles were addressed at 27 monitoring points across a region of 110km×100km in central Japan. The weather data were obtained from the Automated Meteorological Data Acquisition System. The results showed that air temperature in the evenings was linearly related to the elevation above sea level with little perturbations from the weather, wind speed and topography. In contrast, minimum air temperature in the mornings and nocturnal cooling rate were greatly influenced by the above factors. Furthermore, in a complex terrain, the morning air temperature and cooling rate were unrelated to those at nearby points. Therefore, the two temperature traits may not be accurately estimated by using spatial interpolation. Second, two parameters (a & b) of the nocturnal cooling model were determined for each of the 27 monitoring points, and were related to topographical features of the points. Indexes of surface flatness (Sidx), cubical measure by a concavo-convex space (Cidx) and steepness (Ridx) on the level surface at observation were defined and calculated for each point using elevations of the grid points of the Digital National Land Information. The parameter b, which represents thermal conditions and accumulation of cold air, was related to Sidx and Cidx. The parameter a, which represents the extent of air mixing, was related to Ridx. The short-term air temperatures could therefore be estimated on a regional basis with the nocturnal cooling model, whose parameters are determined with the topographical indexes. (author)

  11. Smart Control of Air Climatization System in Function on the Values of Mean Local Radiant Temperature

    Directory of Open Access Journals (Sweden)

    Giuseppe Cannistraro

    2015-08-01

    Full Text Available The hygrothermal comfort indoor conditions are defined as: those environmental conditions in which an individual exposed, expresses a state of satisfaction. These conditions cannot always be achieved anywhere in an optimal way and economically; in some cases they can be obtained only in work environments specific areas. This could be explained because of air conditioning systems designing is generally performed both on the basis of the fundamental parameters’ average values, such as temperature, velocity and relative humidity (Ta, va e φa and derived parameters such as operating temperature and mean radiant one (Top eTmr. However, in some specific cases - large open-spaces or in case of radiating surfaces - the descriptors defining indoor comfort conditions, based on average values, do not provide the optimum values required during the air conditioning systems design phase. This is largely due to the variability of real environmental parameters values compared to the average ones taken as input in the calculation. The results obtained in previous scientific papers on the thermal comfort have been the driving element of this work. It offers a simple, original and clever way of thinking about the new domotic systems for air conditioning, based on the “local mean radiant temperature.” This is a very important parameter when one wants to analyze comfort in environments characterized by the presence of radiating surfaces, as will be seen hereinafter. In order to take into account the effects of radiative exchanges in the open-space workplace, where any occupant may find themselves in different temperature and humidity conditions, this paper proposes an action on the domotic climate control, with ducts and vents air distribution placed in different zones. Comparisons were performed between the parameters values representing the punctual thermal comfort, with the Predicted Mean Vote PMV, in an environment marked by radiating surfaces (i

  12. EFFECTS OF PAVEMENT SURFACE TEMPERATURE ON THE MODIFICATION OF URBAN THERMAL ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    SARAT, Adebayo-Aminu

    2012-01-01

    Full Text Available Urban centres continue to experience escalating average summer temperature over the last fifty years. Temperature in the urban core cites have been rising due to rapid growth of urbanization in the latter half of the twentieth century (Akbari et al., 1989. Outdoor experiments were conducted to investigate the effects of different movement of materials on the urban thermal environment. Meteorological conditions such as air temperature, pavement surface temperature, Relative humidity and wind velocity were recorded to determine temperature differences among Asphalt/concrete, interlocking bricks and grass surfaces.

  13. Experimental study of the air-atomized spray cooling of high-temperature metal

    International Nuclear Information System (INIS)

    An experimental study of heat transfer between a hot metallic surface and water droplets sprayed by a commercial flat pattern air-atomized spray nozzle was conducted. A lattice grid was used to measure the local spray density (Q) along the horizontal (X) and vertical (Y) axes of the local spray region. By measuring the temperature evolution inside the test plate, the surface heat flux was calculated by the inverse heat conduction problem. In the case of no obvious run-off flow on the surface, the temperature TCHF and heat flux qCHF at the critical heat flux (CHF) point increased with Q. Besides, the values of TLeid and qLeid for the Leidenfrost point also showed similar variation. When V = 1.11 × 10−5 m3 s−1, the CHF points at locations around the spray center were forced to transfer to higher surface temperature, due to the run-off water flow from the spray center. Based on the results obtained, mathematical correlations were proposed, signifying the dependence of heat flux in different boiling regimes for water flow rates V ≤ 0.83 × 10−5 m3 s−1. The results obtained in this study will provide a theoretical basis for predicting the temperature of the cold-rolled strip during the spray-cooling process and for designing the cooling process. - Highlights: • Air-atomized water spray cooling of a very high temperature surface was studied. • Correlations of heat flux in different boiling regimes were established. • CHF shifted to higher surface temperature due to the serious run-off water flow

  14. Permanent hydrophilization of outer and inner surfaces of polytetrafluoroethylene tubes using ambient air plasma generated by surface dielectric barrier discharges

    Energy Technology Data Exchange (ETDEWEB)

    Pavliňák, D.; Galmiz, O.; Zemánek, M.; Brablec, A.; Čech, J.; Černák, M., E-mail: cernak@physics.muni.cz [Department of Physical Electronics, Masaryk University, Kotlarska 2, Brno 60200 (Czech Republic)

    2014-10-13

    We present an atmospheric pressure ambient air plasma technique developed for technically simple treatment of inner and/or outer surfaces of plastic tubes and other hollow dielectric bodies. It is based on surface dielectric barrier discharge generating visually diffuse plasma layers along the treated dielectric surfaces using water-solution electrodes. The observed visual uniformity and measured plasma rotational and vibrational temperatures of 333 K and 2350 K indicate that the discharge can be readily applied to material surface treatment without significant thermal effect. This is exemplified by the obtained permanent surface hydrophilization of polytetrafluoroethylene tubes related to the replacement of a high fraction (more than 80%) of the surface fluorine determined by X-ray photoelectron spectroscopy. A tentative explanation of the discharge mechanism based on high-speed camera observations and the discharge current and voltage of measurements is outlined.

  15. On extreme rainfall intensity increases with air temperature

    Science.gov (United States)

    Molnar, Peter; Fatichi, Simone; Paschalis, Athanasios; Gaal, Ladislav; Szolgay, Jan; Burlando, Paolo

    2016-04-01

    The water vapour holding capacity of air increases at about 7% per degree C according to the Clausius-Clapeyron (CC) relation. This is one of the arguments why a warmer future atmosphere, being able to hold more moisture, will generate higher extreme precipitation intensities. However, several empirical studies have recently demonstrated an increase in extreme rain intensities with air temperature above CC rates, in the range 7-14% per degree C worldwide (called super-CC rates). This was observed especially for shorter duration rainfall, i.e. in hourly and finer resolution data (e.g. review in Westra et al., 2014). The super-CC rate was attributed to positive feedbacks between water vapour and the updraft dynamics in convective clouds and lateral supply (convergence) of moisture. In addition, mixing of storm types was shown to be potentially responsible for super-CC rates in empirical studies. Assuming that convective events are accompanied by lightning, we will show on a large rainfall dataset in Switzerland (30 year records of 10-min and 1-hr data from 59 stations) that while the average rate of increase in extreme rainfall intensity (95th percentile) is 6-7% in no-lightning events and 8-9% in lightning events, it is 11-13% per degree C when all events are combined (Molnar et al., 2015). These results are relevant for climate change studies which predict shifts in storm types in a warmer climate in some parts of the world. The observation that extreme rain intensity and air temperature are positively correlated has consequences for the stochastic modelling of rainfall. Most current stochastic models do not explicitly include a direct rain intensity-air temperature dependency beyond applying factors of change predicted by climate models to basic statistics of precipitation. Including this dependency explicitly in stochastic models will allow, for example in the nested modelling approach of Paschalis et al. (2014), the random cascade disaggregation routine to be

  16. Land surface skin temperature climatology: benefitting from the strengths of satellite observations

    International Nuclear Information System (INIS)

    Surface skin temperature observations (Tskin), as obtained by satellite remote sensing, provide useful climatological information of high spatial resolution and global coverage that enhances the traditional ground observations of surface air temperature (Tair) and so, reveal new information about land surface characteristics. This letter analyzes nine years of moderate-resolution imaging spectroradiometer (MODIS) skin temperature observations to present monthly skin temperature diurnal, seasonal, and inter-annual variations at a 0.05 deg. latitude/longitude grid over the global land surface and combines these measurements with other MODIS-based variables in an effort to understand the physical mechanisms responsible for Tskin variations. In particular, skin temperature variations are found to be closely related to vegetation cover, clouds, and water vapor, but to differ from 2 m surface Tair in terms of both physical meaning and magnitude. Therefore, the two temperatures (Tskin and Tair) are complementary in their contribution of valuable information to the study of climate change.

  17. Land surface skin temperature climatology: benefitting from the strengths of satellite observations

    Energy Technology Data Exchange (ETDEWEB)

    Jin Menglin [Department of Meteorology, San Jose State University, 1 Washington Square, San Jose, CA 95192-0104 (United States); Dickinson, Robert E, E-mail: jin@met.sjsu.edu [Jackson School of Geosciences, University of Texas at Austin (United States)

    2010-10-15

    Surface skin temperature observations (T{sub skin}), as obtained by satellite remote sensing, provide useful climatological information of high spatial resolution and global coverage that enhances the traditional ground observations of surface air temperature (T{sub air}) and so, reveal new information about land surface characteristics. This letter analyzes nine years of moderate-resolution imaging spectroradiometer (MODIS) skin temperature observations to present monthly skin temperature diurnal, seasonal, and inter-annual variations at a 0.05 deg. latitude/longitude grid over the global land surface and combines these measurements with other MODIS-based variables in an effort to understand the physical mechanisms responsible for T{sub skin} variations. In particular, skin temperature variations are found to be closely related to vegetation cover, clouds, and water vapor, but to differ from 2 m surface T{sub air} in terms of both physical meaning and magnitude. Therefore, the two temperatures (T{sub skin} and T{sub air}) are complementary in their contribution of valuable information to the study of climate change.

  18. HTPro: Low-temperature Surface Hardening of Stainless Steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Somers, Marcel A. J.

    Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance.......Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance....

  19. Extended Reconstructed Sea Surface Temperature (ERSST), Version 4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly sea surface temperature analysis on a 2x2 degree grid derived from the...

  20. NOAA Global Surface Temperature Dataset, Version 4.0

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Global Surface Temperature Dataset (NOAAGlobalTemp) is derived from two independent analyses: the Extended Reconstructed Sea Surface Temperature (ERSST)...

  1. Merged Land and Ocean Surface Temperature, Version 3.5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The historical Merged Land-Ocean Surface Temperature Analysis (MLOST) is derived from two independent analyses, an Extended Reconstructed Sea Surface Temperature...

  2. Ground surface temperature simulation for different land covers

    Science.gov (United States)

    Herb, William R.; Janke, Ben; Mohseni, Omid; Stefan, Heinz G.

    2008-07-01

    SummaryA model for predicting temperature time series for dry and wet land surfaces is described, as part of a larger project to assess the impact of urban development on the temperature of surface runoff and coldwater streams. Surface heat transfer processes on impervious and pervious land surfaces were investigated for both dry and wet weather periods. The surface heat transfer equations were combined with a numerical approximation of the 1-D unsteady heat diffusion equation to calculate pavement and soil temperature profiles to a depth of 10 m. Equations to predict the magnitude of the radiative, convective, conductive and evaporative heat fluxes at a dry or wet surface, using standard climate data as input, were developed. A model for the effect of plant canopies on surface heat transfer was included for vegetated land surfaces. Given suitable climate data, the model can simulate the land surface and sub-surface temperatures continuously throughout a six month time period or for a single rainfall event. Land surface temperatures have been successfully simulated for pavements, bare soil, short and tall grass, a forest, and two agricultural crops (corn and soybeans). The simulations were run for three different locations in US, and different years as imposed by the availability of measured soil temperature and climate data. To clarify the effect of land use on surface temperatures, the calibrated coefficients for each land use and the same soil coefficients were used to simulate surface temperatures for a six year climate data set from Albertville, MN. Asphalt and concrete give the highest surface temperatures, as expected, while vegetated surfaces gave the lowest. Bare soil gives surface temperatures that lie between those for pavements and plant-covered surfaces. The soil temperature model predicts hourly surface temperatures of bare soil and pavement with root-mean-square errors (RMSEs) of 1-2 °C, and hourly surface temperatures of vegetation-covered surfaces

  3. Trend patterns in global sea surface temperature

    DEFF Research Database (Denmark)

    Barbosa, S.M.; Andersen, Ole Baltazar

    2009-01-01

    Isolating long-term trend in sea surface temperature (SST) from El Nino southern oscillation (ENSO) variability is fundamental for climate studies. In the present study, trend-empirical orthogonal function (EOF) analysis, a robust space-time method for extracting trend patterns, is applied to...... isolate low-frequency variability from time series of SST anomalies for the 1982-2006 period. The first derived trend pattern reflects a systematic decrease in SST during the 25-year period in the equatorial Pacific and an increase in most of the global ocean. The second trend pattern reflects mainly ENSO...... variability in the Pacific Ocean. The examination of the contribution of these low-frequency modes to the globally averaged SST fluctuations indicates that they are able to account for most (>90%) of the variability observed in global mean SST. Trend-EOFs perform better than conventional EOFs when the...

  4. Plutonium in soil and surface air in Thailand

    International Nuclear Information System (INIS)

    Plutonium in soil and surface air in the central part of Thailand have been underinvestigated. Dissolve the sample in potassium fluoride and pyrosulfate fusions, and precipitate barium sulfate. The plutonium is separated by solvent extraction with HDEHP from perchloric acid medium. Finally the plutonium is coprecipitated with 50 μg of cerium carrier. The precipitate is filtered on a 25 mm. glossy membrane filter with a 0.1 μm pore size, and analyzed with a 300 mm2 surface-barrier detector at about 20 percent counting efficiency. The range of Plutonium-239, 240 in soil were 0.002 to 0.157 pCi/g.dry. Plutonium-239, 240 in surface air in July 1981 were 7.7 +- 2.1 aCi/m3 and lower than the limit of detector from August to November 1981

  5. Air - Ground - Bedrock Temperature Coupling, Its Monitoring at Borehole Climate Observatories

    Science.gov (United States)

    Cermák, V.

    2012-04-01

    Reconstructing ground surface temperature (GST) histories from present-day temperature-depth logs is now generally accepted as one of the independent and physically justified method to obtain information about the past climate history on the time scale of hundreds to thousands years. Any temperature change at the Earth`s surface slowly propagates downward and deeper we go farther back in time the measured temperature carries certain memory on what has happened on the surface in the past. Due to diffusive character of the process, however, the resolution quickly decreases for the remote events and the reconstructed GST at a given moment is a weighted average of temperature over a certain period of time. For better understanding of the temperature state in the subsurface T(z) logs can be suitably completed with long-run temperature-time monitoring at selected depth intervals, namely within the near-surface active layer affected by seasonal temperature variations (usually uppermost 30-40 m). In addition to GST inversions applied on deep T(z) profiles existing all over the world, several permanent borehole climate observatories were actually established in the last two decades to test the validity of the assumption that GST variations track the SAT (surface air temperature) changes as well as to study various environmental/local effects, such as the vegetation cover type/change, rain/snow precipitation, thawing/melting/freezing, etc. which controls the whole heat transfer process. Long-term monitoring of the shallow subsurface temperature field in suitably geographically located sites may additionally also help to understand the different conditions in e.g. urban vs. countryside environments and to assess the potential anthropogenic contribution to the present-day warming rate within the natural climate variability. This presentation summarizes main results obtained at the Czech borehole sites since 1992 completed with brief comparison of similar results collected

  6. Optimization of microwave-assisted hot air drying conditions of okra using response surface methodology.

    Science.gov (United States)

    Kumar, Deepak; Prasad, Suresh; Murthy, Ganti S

    2014-02-01

    Okra (Abelmoschus esculentus) was dried to a moisture level of 0.1 g water/g dry matter using a microwave-assisted hot air dryer. Response surface methodology was used to optimize the drying conditions based on specific energy consumption and quality of dried okra. The drying experiments were performed using a central composite rotatable design for three variables: air temperature (40-70 °C), air velocity (1-2 m/s) and microwave power level (0.5-2.5 W/g). The quality of dried okra was determined in terms of color change, rehydration ratio and hardness of texture. A second-order polynomial model was well fitted to all responses and high R(2) values (>0.8) were observed in all cases. The color change of dried okra was found higher at high microwave power and air temperatures. Rehydration properties were better for okra samples dried at higher microwave power levels. Specific energy consumption decreased with increase in microwave power due to decrease in drying time. The drying conditions of 1.51 m/s air velocity, 52.09 °C air temperature and 2.41 W/g microwave power were found optimum for product quality and minimum energy consumption for microwave-convective drying of okra. PMID:24493879

  7. The Relationship Between Surface Temperature Anomaly Time Series and those of OLR, Water Vapor, and Cloud Cover as Observed Using Nine Years of AIRS Version-5 Level-3 Products

    Science.gov (United States)

    Susskind, Joel; Molnar, Gyula; Iredell, Lena

    2011-01-01

    Outline: (1) Comparison of AIRS and CERES anomaly time series of outgoing longwave radiation (OLR) and OLR(sub CLR), i.e. Clear Sky OLR (2) Explanation of recent decreases in global and tropical mean values of OLR (3) AIRS "Short-term" Longwave Cloud Radiative Feedback -- A new product

  8. Quantification of air plasma chemistry for surface disinfection

    Science.gov (United States)

    Pavlovich, Matthew J.; Clark, Douglas S.; Graves, David B.

    2014-12-01

    Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O3) and nitrogen oxides (NO and NO2, or NOx) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NOx mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications.

  9. Quantification of air plasma chemistry for surface disinfection

    International Nuclear Information System (INIS)

    Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O3) and nitrogen oxides (NO and NO2, or NOx) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NOx mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications. (paper)

  10. Low Temperature Surface Carburization of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Sunniva R; Heuer, Arthur H; Sikka, Vinod K

    2007-12-07

    Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces. The carbon in the interstitial spaces of the alloy crystals makes the surface harder than ever achieved before by more conventional heat treating or diffusion process. The carbon solid solution manifests a Vickers hardness often exceeding 1000 HV (equivalent to 70 HRC). This project objective was to extend the LTCSS treatment to other austenitic alloys, and to quantify improvements in fatigue, corrosion, and wear resistance. Highlights from the research include the following: • Extension of the applicability of the LTCSS process to a broad range of austenitic and duplex grades of steels • Demonstration of LTCSS ability for a variety of different component shapes and sizes • Detailed microstructural characterization of LTCSS-treated samples of 316L and other alloys

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  12. Linear and nonlinear post-processing of numerically forecasted surface temperature

    OpenAIRE

    M. Casaioli; Mantovani, R; Proietti Scorzoni, F.; S. Puca; A. Speranza; Tirozzi, B.

    2003-01-01

    In this paper we test different approaches to the statistical post-processing of gridded numerical surface air temperatures (provided by the European Centre for Medium-Range Weather Forecasts) onto the temperature measured at surface weather stations located in the Italian region of Puglia. We consider simple post-processing techniques, like correction for altitude, linear regression from different input parameters and Kalman filtering, as...

  13. Temperature dependence of Hertzian indentation fracture surface energy of ThO2

    International Nuclear Information System (INIS)

    The fracture surface energy of ThO/sub 2/ was measured between room temperature and 400/degree/C using the Hertzian indentation technique with cold or preheated steel and alumina indentors. The value of the surface energy of the thorium dioxide decreased sharply with temperature. The ThO/sub 2/ was chosen for experiments as it does not oxidize on annealing in air. 38 refs

  14. [Calculating method for crop water requirement based on air temperature].

    Science.gov (United States)

    Tao, Guo-Tong; Wang, Jing-Lei; Nan, Ji-Qin; Gao, Yang; Chen, Zhi-Fang; Song, Ni

    2014-07-01

    The importance of accurately estimating crop water requirement for irrigation forecast and agricultural water management has been widely recognized. Although it has been broadly adopted to determine crop evapotranspiration (ETc) via meteorological data and crop coefficient, most of the data in whether forecast are qualitative rather than quantitative except air temperature. Therefore, in this study, how to estimate ETc precisely only using air temperature data in forecast was explored, the accuracy of estimation based on different time scales was also investigated, which was believed to be beneficial to local irrigation forecast as well as optimal management of water and soil resources. Three parameters of Hargreaves equation and two parameters of McClound equation were corrected by using meteorological data of Xinxiang from 1970 to 2010, and Hargreaves equation was selected to calculate reference evapotranspiration (ET0) during the growth period of winter wheat. A model of calculating crop water requirement was developed to predict ETc at time scales of 1, 3, and 7 d intervals through combining Hargreaves equation and crop coefficient model based on air temperature. Results showed that the correlation coefficients between measured and predicted values of ETc reached 0.883 (1 d), 0.933 (3 d), and 0.959 (7 d), respectively. The consistency indexes were 0.94, 0.95 and 0.97, respectively, which showed that forecast error decreased with the increasing time scales. Forecasted accuracy with an error less than 1 mm x d(-1) was more than 80%, and that less than 2 mm x d(-1) was greater than 90%. This study provided sound basis for irrigation forecast and agricultural management in irrigated areas since the forecasted accuracy at each time scale was relatively high. PMID:25345053

  15. Evaluation of air temperature distribution using thermal image under conditions of nocturnal radiative cooling in winter season over Shikoku area

    International Nuclear Information System (INIS)

    Using the thermal images offered by the infra-red thermometer and the LANDSAT, the air temperature distribution over mountainous regions were estimated under conditions of nocturnal radiative cooling in the winter season. The thermal image analyses by using an infra-red thermometer and the micrometeological observation were carried out around Zentsuji Kagawa prefecture. At the same time, the thermal image analyses were carried out by using the LANDSAT data. The LANDSAT data were taken on Dec. 7, 1984 and Dec. 5, 1989. The scenes covered the west part of Shikoku, southwest of Japan.The results were summarized as follows:Values of the surface temperature of trees, which were measured by an infra-red thermometer, were almost equal to the air temperature. On the other hand, DN values detected by LANDSAT over forest area were closely related with air temperature observed by AMeDAS. Therefore, it is possible to evaluate instantaneously a spatial distribution of the nocturnal air temperature from thermal image.The LANDSAT detect a surface temperature over Shikoku area only at 21:30. When radiative cooling was dominant, the thermal belt and the cold air lake were already formed on the mountain slopes at 21:30. Therfore, it is possible to estimate the characteristic of nocturnal temperature distribution by using LANDSAT data.It became clear that the temperature distribution estimated by thermal images offered by the infra-red thermometer and the LANDSAT was useful for the evaluation of rational land use for winter crops

  16. Using the Surface Temperature-Albedo Space to Separate Regional Soil and Vegetation Temperatures from ASTER Data

    Directory of Open Access Journals (Sweden)

    Lisheng Song

    2015-05-01

    Full Text Available Soil and vegetation component temperatures in non-isothermal pixels encapsulate more physical meaning and are more applicable than composite temperatures. The component temperatures however are difficult to be obtained from thermal infrared (TIR remote sensing data provided by single view angle observations. Here, we present a land surface temperature and albedo (T-α space approach combined with the mono-surface energy balance (SEB-1S model to derive soil and vegetation component temperatures. The T-α space can be established from visible and near infrared (VNIR and TIR data provided by single view angle observations. This approach separates the soil and vegetation component temperatures from the remotely sensed composite temperatures by incorporating soil wetness iso-lines for defining equivalent soil temperatures; this allows vegetation temperatures to be extracted from the T-α space. This temperature separation methodology was applied to advanced scanning thermal emission and reflection radiometer (ASTER VNIR and high spatial resolution TIR image data in an artificial oasis area during the entire growing season. Comparisons with ground measurements showed that the T-α space approach produced reliable soil and vegetation component temperatures in the study area. Low root mean square error (RMSE values of 0.83 K for soil temperatures and 1.64 K for vegetation temperatures, respectively, were obtained, compared to component temperatures measurements from a ground-based thermal camera. These results support the use of soil wetness iso-lines to derive soil surface temperatures. It was also found that the estimated vegetation temperatures were extremely close to the near surface air temperature observations when the landscape is well watered under full vegetation cover. More robust soil and vegetation temperature estimates will improve estimates of soil evaporation and vegetation transpiration, leading to more reliable the monitoring of crop

  17. The impact of different cooling strategies on urban air temperatures: the cases of Campinas, Brazil and Mendoza, Argentina

    Science.gov (United States)

    Alchapar, Noelia Liliana; Cotrim Pezzuto, Claudia; Correa, Erica Norma; Chebel Labaki, Lucila

    2016-07-01

    This paper describes different ways of reducing urban air temperature and their results in two cities: Campinas, Brazil—a warm temperate climate with a dry winter and hot summer (Cwa), and Mendoza, Argentina—a desert climate with cold steppe (BWk). A high-resolution microclimate modeling system—ENVI-met 3.1—was used to evaluate the thermal performance of an urban canyon in each city. A total of 18 scenarios were simulated including changes in the surface albedo, vegetation percentage, and the H/W aspect ratio of the urban canyons. These results revealed the same trend in behavior for each of the combinations of strategies evaluated in both cities. Nevertheless, these strategies produce a greater temperature reduction in the warm temperate climate (Cwa). Increasing the vegetation percentage reduces air temperatures and mean radiant temperatures in all scenarios. In addition, there is a greater decrease of urban temperature with the vegetation increase when the H/W aspect ratio is lower. Also, applying low albedo on vertical surfaces and high albedo on horizontal surfaces is successful in reducing air temperatures without raising the mean radiant temperature. The best combination of strategies—60 % of vegetation, low albedos on walls and high albedos on pavements and roofs, and 1.5 H/W—could reduce air temperatures up to 6.4 °C in Campinas and 3.5 °C in Mendoza.

  18. Impact of Aspect Ratio and Solar Heating on Street Conyn Air Temperature

    Directory of Open Access Journals (Sweden)

    Rizwan Ahmed Memon

    2011-01-01

    Full Text Available The results obtained from RNG (Re-Normalization Group version of k-? turbulence model are reported in this study. The model is adopted to elucidate the impact of different building aspect ratios (i.e., ratio of building-height-to-street-canyon-width and solar heating on temperatures in street canyon. The validation of Navier-Stokes and energy transport equations showed that the model prediction for air-temperature and ambient wind provides reasonable accuracy. The model was applied on AR (Aspect Ratios one to eight and surface temperature difference (??s-a of 2 -8. Notably, air-temperatures were higher in high AR street canyons in particular on the leeward side of the street canyon. Further investigation showed that the difference between the air-temperature of high and low AR street canyons ( AR was positive and high with higher ??s-a. Conversely, the AR become negative and low gradually with lower values of ??s-a. These results could be very beneficial for the city and regional planners, civil engineers and HVAC experts who design street canyons and strive for human thermal comfort with minimum possible energy requirements.

  19. Impact of aspect ratio and solar heating on street canyon air temperature

    International Nuclear Information System (INIS)

    The results obtained from RNG (Re-Normalization Group) version of k-and turbulence model are reported in this study. The model is adopted to elucidate the impact of different building aspect ratios (i.e., ratio of building-height-to-street-canyon-width) and solar heating on temperatures in street canyon. The validation of Navier-Stokes and energy an sport equations showed that the model prediction for air-temperature and ambient wind provides reasonable accuracy. The model was applied on AR (Aspect Ratios) one to eight and surface temperature difference (delta and theta/sub s-a/)) of 2 -8. Notably, air-temperatures were higher in high AR street canyons in particular on the leeward side of the street canyon. Further investigation showed that the difference between the air-temperature 'high and low AR street canyons (AR) was positive and high with higher delta and theta/sub s-a/) conversely, the AR become negative and low gradually with lower values of delta and theta(/sub s-a/). These results could be very beneficial for the city and regional planners, civil engineers Id HVAC experts who design street canyons and strive for human thermal comfort with minimum possible energy requirements. (author)

  20. Characteristics of the air temperature in The Central Moldavian Tableland between Siret and Şacovăţ

    Directory of Open Access Journals (Sweden)

    Vasile BUDUI

    2008-07-01

    Full Text Available The air temperature is one of the most important climatic parameters, that define the geographic regions. The temperature regim is influenced by the infrared radiation and the transformation in heat at the contact with active surface, also by the atmosphericcirculation, that air mases with different thermic characteristics succeed. Low temperatures aredetermined by the crossing to east of the country of the subarctic continental air masses or themaritim subpolar masses. High temperatures are determined by the tropical air masses thatcome from south-east, in the summer, or from west, in winter. For the spatialisation of the airtemperature we used GIS programs: TNT Mips, ArcGIS 9.2 and SAGA.

  1. Influence of Air Temperature Difference on the Snow Melting Simulation of SWAT Model

    Science.gov (United States)

    YAN, Y.; Onishi, T.

    2013-12-01

    The temperature-index models are commonly used to simulate the snowmelt process in mountain areas because of its good performance, low data requirements, and computational simplicity. Widely used distributed hydrological model: Soil and Water Assessment Tool (SWAT) model is also using a temperature-index module. However, the lack of monitoring air temperature data still involves uncertainties and errors in its simulation performance especially in data sparse area. Thus, to evaluate the different air temperature data influence on the snow melt of the SWAT model, five different air temperature data are applied in two different Russia basins (Birobidjan basin and Malinovka basin). The data include the monitoring air temperature data (TM), NCEP reanalysis data (TNCEP), the dataset created by inverse distance weighted interpolation (IDW) method (TIDW), the dataset created by improved IDW method considering the elevation influence (TIDWEle), and the dataset created by using linear regression and MODIS Land Surface Temperature (LST) data (TLST). Among these data, the TLST , the TIDW and TIDWEle data have the higher spatial density, while the TNCEP and TM DATA have the most valid monitoring value for daily scale. The daily simulation results during the snow melting seasons (March, April and May) showed reasonable results in both test basins for all air temperature data. While R2 and NSE in Birobidjan basin are around 0.6, these values in Malinovka basin are over 0.75. Two methods: Generalized Likelihood Uncertainty Estimation (GLUE) and Sequential Uncertainty Fitting, version. 2 (SUFI-2) were used for model calibration and uncertainty analysis. The evolution index is p-factor which means the percentage of measured data bracketed by the 95% Prediction Uncertainty (95PPU). The TLST dataset always obtained the best results in both basins compared with other datasets. On the other hand, the two IDW based method get the worst results among all the scenarios. Totally, the

  2. Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

    CERN Document Server

    2009-01-01

    Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.

  3. How micropatterns and air pressure affect splashing on surfaces

    CERN Document Server

    Tsai, Peichun; van de Raa, Matthias; Lohse, Detlef

    2010-01-01

    We experimentally investigate the splashing mechanism of a millimeter-sized ethanol drop impinging on a structured solid surface, comprised of micro-pillars, through side-view and top-view high speed imaging. By increasing the impact velocity we can tune the impact outcome from a gentle deposition to a violent splash, at which tiny droplets are emitted as the liquid sheet spreads laterally. We measure the splashing threshold for different micropatterns and find that the arrangement of the pillars significantly affects the splashing outcome. In particular, directional splashing in direction in which air flow through pattern is possible. Our top-view observations of impact dynamics reveal that an trapped air is responsible for the splashing. Indeed by lowering the pressure of the surrounding air we show that we can suppress the splashing in the explored parameter regime.

  4. Temperature and Humidity Control in Air-Conditioned Buildings with lower Energy Demand and increased Indoor Air Quality

    DEFF Research Database (Denmark)

    Paul, Joachim; Martos, E. T.

    2003-01-01

    Air-conditioning is not only a matter of temperature control. Thermal comfort and good indoor air quality are mainly a matter of humidity. Human health and well being may suffer seriously from inadequate humidity and/or too low temperatures in a room. A case study involving supermarket air-conditioning....... Binary Ice as secondary refrigerant for air-conditioning purposes is an economical and technically feasible solution in any climate. Whatever chilled water can do in an air-conditioning installation ? Binary Ice can do it better....

  5. Variation of the shower lateral spread with air temperature at the ground

    Science.gov (United States)

    Wilczyńska, B.; Engel, R.; Homola, P.; Keilhauer, B.; Klages, H.; Pękala, J.; Wilczyński, H.

    The vertical profile of air density at a given site varies considerably with time. Well understood seasonal differences are present, but sizeable effects on shorter time scales, like day to night or day to day variations, are also observed. In consequence, the Moliere radius changes, influencing the lateral distribution of particles in the air showers and therefore may influence the shower detection in surface detector arrays. In air shower reconstruction, usually seasonal average profiles of the atmosphere are used, because local daily measurements of the profile are rarely available. Therefore, the daily fluctuations of the atmosphere are not accounted for. This simplification increases the inaccuracies of shower reconstruction. We show that a universal correlation exists between the ground temperature and the shape of the atmospheric profile, up to altitudes of several kilometers, hence providing a method to reduce inaccuracies in shower reconstruction due to weather variation.

  6. Meso-scale wrinkled coatings to improve heat transfers of surfaces facing ambient air

    International Nuclear Information System (INIS)

    Meso-scale (micrometer-to submillimeter-scale) wrinkled surfaces coated on steel sheets used in outdoor storage and transport facilities for industrial low-temperature liquids were discovered to efficiently increase convective heat transfer between ambient air and the surface. The radiative and convective heat transfer coefficients of various wrinkled surfaces, which were formed by coating steel sheets with several types of shrinkable paints, were examined. The convective heat transfer coefficient of a surface colder than ambient air monotonically changed with average height difference and interval distance of the wrinkle undulation, where the proportions were 0.0254 and 0.0054 W/m2/K/μm, respectively. With this wrinkled coating, users can lower the possibility of condensation and reduce rust and maintenance cost of facilities for industrial low-temperature liquids. From the point of view of manufacturers, this coating method can be easily adapted to conventional manufacturing processes. - Highlights: • Various wrinkled surfaces were fabricated by a practical process. • Topographical effect on convection was parameterized separately from radiation. • Meso-scale wrinkled coatings increased convective heat transfer with ambient air. • Maintenance cost of outdoor steel sheets due to condensation can be reduced

  7. Cloud-induced uncertainties in AIRS and ECMWF temperature and specific humidity

    Science.gov (United States)

    Wong, Sun; Fetzer, Eric J.; Schreier, Mathias; Manipon, Gerald; Fishbein, Evan F.; Kahn, Brian H.; Yue, Qing; Irion, Fredrick W.

    2015-03-01

    The uncertainties of the Atmospheric Infrared Sounder (AIRS) Level 2 version 6 specific humidity (q) and temperature (T) retrievals are quantified as functions of cloud types by comparison against Integrated Global Radiosonde Archive radiosonde measurements. The cloud types contained in an AIRS/Advanced Microwave Sounding Unit footprint are identified by collocated Moderate Resolution Imaging Spectroradiometer retrieved cloud optical depth (COD) and cloud top pressure. We also report results of similar validation of q and T from European Centre for Medium-Range Weather Forecasts (ECMWF) forecasts (EC) and retrievals from the AIRS Neural Network (NNW), which are used as the initial state for AIRS V6 physical retrievals. Differences caused by the variation in the measurement locations and times are estimated using EC, and all the comparisons of data sets against radiosonde measurements are corrected by these estimated differences. We report in detail the validation results for AIRS GOOD quality control, which is used for the AIRS Level 3 climate products. AIRS GOOD quality q reduces the dry biases inherited from the NNW in the middle troposphere under thin clouds but enhances dry biases in thick clouds throughout the troposphere (reaching -30% at 850 hPa near deep convective clouds), likely because the information contained in AIRS retrievals is obtained in cloud-cleared areas or above clouds within the field of regard. EC has small moist biases (~5-10%), which are within the uncertainty of radiosonde measurements, in thin and high clouds. Temperature biases of all data are within ±1 K at altitudes above the 700 hPa level but increase with decreasing altitude. Cloud-cleared retrievals lead to large AIRS cold biases (reaching about -2 K) in the lower troposphere for large COD, enhancing the cold biases inherited from the NNW. Consequently, AIRS GOOD quality T root-mean-squared errors (RMSEs) are slightly smaller than the NNW errors in thin clouds (1.5-2.5 K) but

  8. An experimental study of thermal comfort at different combinations of air and mean radiant temperature

    DEFF Research Database (Denmark)

    Simone, Angela; Olesen, Bjarne W.

    2009-01-01

    It is often discussed if a person prefers a low air temperature (ta) and a high mean radiant temperature (tr), vice-versa or it does not matter as long as the operative temperature is acceptable. One of the hypotheses is that it does not matter for thermal comfort but for perceived air quality, a...... lower air temperature is preferred. This paper presents an experimental study with 30 human subjects exposed to three different combinations of air- and mean radiant temperature with an operative temperature around 23 °C. The subjects gave subjective evaluations of thermal comfort and perceived air...... quality during the experiments. The PMV-index gave a good estimation of thermal sensation vote (TSV) when the air and mean radiant temperature were the same. In the environment with different air- and mean radiant temperatures, a thermal comfort evaluation shows an error up to 1 scale unit on the 7-point...

  9. Coffee husks gasification using high temperature air/steam agent

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Lugano; Yang, Weihong; Blasiak, Wlodzimierz [Division of Energy and Furnace Technology, Department of Materials Science and Engineering, Royal Institute of Technology (KTH), Brinellvaegen 23, SE 100 44 Stockholm (Sweden); John, Geoffrey R.; Mhilu, Cuthbert F. [Department of Mechanical and Industrial Engineering, University of Dar es Salaam, P O Box 35131 Dar es Salaam (Tanzania)

    2010-10-15

    Analyses made on the world's biomass energy potential show that biomass energy is the most abundant sustainable renewable energy. The available technical biomass energy potential surpasses the total world's consumption levels of petroleum oils, coal and natural gas. In order to achieve a sustainable harnessing of the biomass energy potential and to increase its contribution to the world's primary energy consumption, there is therefore a need to develop and sustain contemporary technologies that increase the biomass-to-energy conversion. One such technology is the high temperature air/steam gasification (HTAG) of biomass. In this paper we present findings of gasification experimental studies that were conducted using coffee husks under high temperature conditions. The experiments were performed using a batch facility, which was maintained at three different gasification temperatures of 900 C, 800 C, and 700 C. The study findings exhibited the positive influence of high temperature on increasing the gasification process. Chars left while gasifying at 800 C and 700 C were respectively 1.5 and 2.4 times that for the case of 900 C. Furthermore, increased gasification temperature led to a linear increment of CO concentration in the syngas for all gasification conditions. The effect was more pronounced for the generally poorly performing gasification conditions of N{sub 2} and 2% oxygen concentration. When gasification temperature was increased from 700 C to 900 C the CO yield for the 2% O{sub 2} concentration increased by 6 times and that of N{sub 2} condition by 2.5 times. The respective increment for the 3% and 4% O{sub 2} conditions were only twofold. This study estimated the kinetic parameters for the coffee husks thermal degradation that exhibited a reaction mechanism of zero order with apparent activation energy of 161 kJ/mol and frequency factor of 3.89 x 10{sup 4}/min. (author)

  10. Strengthening relationship between ENSO and western Russian summer surface temperature

    Science.gov (United States)

    Sun, Cheng; Li, Jianping; Ding, Ruiqiang

    2016-01-01

    Western Russia (WR) experienced an extremely hot summer in 2010 that caused tremendous social and economic losses. The WR summer surface temperature (WRST) in the observational record is characterized by substantial interannual variability superimposed on the secular warming trend. Analysis of the 130 year observational record reveals that a strong and significant inverse relationship between WRST interannual variability and the tropical El Niño-Southern Oscillation (ENSO) has emerged during the past three decades. The ENSO influence on the summer extratropical atmospheric circulation was weak before 1980 but became strong and significant afterward, showing a structure similar to the East Atlantic/WR teleconnection pattern. This pattern is associated with rising/falling upper level geopotential height over WR, which leads to the warming/cooling of surface and tropospheric air temperatures. Numerical simulations from a theoretical linear baroclinic model and Atmospheric Model Intercomparison Project models further suggest that the enhancement of the ENSO teleconnection to WR may be attributable to a change in the ENSO-related tropical thermal forcing. A tripole-type rainfall anomaly pattern over tropical Pacific and Atlantic is found to be associated with ENSO in the past three decades. The tripole heating pattern can excite a Rossby wave that extends northwestward reaching WR and is necessary for the strong influence of ENSO on WR summer climate.

  11. Urban air temperature anomalies and their relation to soil moisture observed in the city of Hamburg

    Directory of Open Access Journals (Sweden)

    Sarah Wiesner

    2014-09-01

    Full Text Available The spatial variability of the urban air temperature for the city of Hamburg is analyzed based upon a one-year dataset of meteorological and pedological measurements. As local air temperature anomalies are subject to land-use and surface cover, they are monitored by a network of measurement stations within three different urban structures. Mean annual temperature deviations are found to be +1.0K$+1.0\\,\\text{K}$ for inner city sites and +0.25K$+0.25\\,\\text{K}$ to -0.2K$-0.2\\,\\text{K}$ for suburban sites compared to a rural reference. The nocturnal urban heat island (UHI is identified and averages +1.7K$+1.7\\,\\text{K}$ at the inner city stations, +0.7K$+0.7\\,\\text{K}$ at a suburban district housing area and +0.3K$+0.3\\,\\text{K}$ at a nearby green space. The observed UHI effect is most prominent when the wind speed is low (≤2ms-1$\\leq2\\,\\text{ms}^{-1}$ and the sky is only partly cloudy (≤6∕8th$\\leq6/8^{\\text{th}}$. In spring 2011 an average inner city UHI of up to +5.2K$+5.2\\,\\text{K}$ is observed during situations matching these conditions, while the extraordinary dry fall of 2011 lead to remarkably high air temperature differences at all observed stations. As expected, no evidence for a significant impact of topsoil moisture on nighttime UHI effect is found. The analysis of air temperature anomalies during daytime results in an annual mean deviation of -0.5K$-0.5\\,\\text{K}$ above unsealed, vegetated surfaces from a sealed site during days with a turbulent mixing induced by wind speed >2ms-1$>2\\,\\text{ms}^{-1}$. Here, there is an indication for a relation between the water content of upper soil layers and the warming of air: 11 to 17 % of the variance of the diurnal air temperature span is found to be explained by the soil water content for selected relevant days.

  12. TECHNOLOGICAL POSSIBILITIES OF CONTACTLESS MEASURING THE BODY SURFACE TEMPERATURE

    OpenAIRE

    Kateřina Švejdová; Miloslav Šoch; Anna Šimková; Luboš Zábranský; Luboš Smutný; Šárka Smutná; Bohuslav Čermák

    2013-01-01

    The regular measuring of the body surface temperature can help to evaluate health condition of animals and react immediately on the first symptoms of illness. There are many of technological possibilities of contactless measuring the body surface temperature. It is important to find the right part of the body which the temperature will show the first possible symptoms of illness. This experiment with dairy cows and heifers was realized at the farm in Petrovice. The body surface temperature an...

  13. Sea Ice Surface Temperature Product from the Moderate Resolution Imaging Spectroradiometer (MODIS)

    Science.gov (United States)

    Hall, Dorothy K.; Key, Jeffrey R.; Casey, Kimberly A.; Riggs, George A.; Cavalieri, Donald J.

    2003-01-01

    Global sea ice products are produced from the Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) on board both the Terra and Aqua satellites. Daily sea ice extent and ice-surface temperature (IST) products are available at 1- and 4-km resolution. Validation activities have been undertaken to assess the accuracy of the MODIS IST product at the South Pole station in Antarctica and in the Arctic Ocean using near-surface air-temperature data from a meteorological station and drifting buoys. Results from the study areas show that under clear skies, the MODIS ISTs are very close to those of the near-surface air temperatures with a bias of -1.1 and -1.2 K, and an uncertainty of 1.6 and 1.7 K, respectively. It is shown that the uncertainties would be reduced if the actual temperature of the ice surface were reported instead of the near-surface air temperature. It is not possible to get an accurate IST from MODIS in the presence of even very thin clouds or fog, however using both the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) and the MODIS on the Aqua satellite, it may be possible to develop a relationship between MODIS-derived IST and ice temperature derived from the AMSR-E. Since the AMSR-E measurements are generally unaffected by cloud cover, they may be used to complement the MODIS IST measurements.

  14. Precipitation and temperature changes in the major Chinese river basins during 1957-2013 and links to sea surface temperature

    Science.gov (United States)

    Tian, Qing; Prange, Matthias; Merkel, Ute

    2016-05-01

    The variation characteristics of precipitation and temperature in the three major Chinese river basins (Yellow River, Yangtze River and Pearl River) in the period of 1957-2013 were analyzed on an annual and seasonal basis, as well as their links to sea surface temperature (SST) variations in the tropical Pacific and Indian Ocean on both interannual and decadal time scales. Annual mean temperature of the three river basins increased significantly overall since 1957, with an average warming rate of about 0.19 °C/10a, but the warming was characterized by a staircase form with steps around 1987 and 1998. The significant increase of annual mean temperature could mostly be attributed to the remarkable warming trend in spring, autumn and winter. Warming rates in the northern basins were generally much higher than in the southern basins. However, both the annual precipitation and seasonal mean precipitation of the three river basins showed little change in the study area average, but distinct interannual variations since 1957 and clear regional differences. An overall warming-wetting tendency was found in the northwestern and southeastern river basins in 1957-2013, while the central regions tended to become warmer and drier. Results from a Maximum Covariance Analysis (MCA) showed that the interannual variations of seasonal mean precipitation and surface air temperature over the three river basins were both associated with the El Niño-Southern Oscillation (ENSO) since 1957. ENSO SST patterns affected precipitation and surface air temperature variability throughout the year, but with very different response patterns in the different seasons. For instance, temperature in most of the river basins was positively correlated with central-eastern equatorial Pacific SST in winter and spring, but negatively correlated in summer and autumn. On the decadal time scale, the seasonal mean precipitation and surface air temperature variations were strongly associated with the Pacific

  15. Improving the indoor air quality by using a surface emissions trap

    Science.gov (United States)

    Markowicz, Pawel; Larsson, Lennart

    2015-04-01

    The surface emissions trap, an adsorption cloth developed for reducing emissions of volatile organic compounds and particulate matter from surfaces while allowing evaporation of moisture, was used to improve the indoor air quality of a school building with elevated air concentrations of 2-ethyl-1-hexanol. An improvement of the perceived air quality was noticed a few days after the device had been attached on the PVC flooring. In parallel, decreased air concentrations of 2-ethyl-1-hexanol were found as well as a linear increase of the amounts of the same compound adsorbed on the installed cloth as observed up to 13 months after installation. Laboratory studies revealed that the performance of the device is not affected by differences in RH (35-85%), temperature (30-40 °C) or by accelerated aging simulating up to 10 years product lifetime, and, from a blinded exposure test, that the device efficiently blocks chemical odors. This study suggests that the device may represent a fast and efficient means of restoring the indoor air quality in a building e.g. after water damage leading to irritating and potentially harmful emissions from building material surfaces indoors.

  16. Effect of surface free energy of acetylene black powder on air electrode performance

    Institute of Scientific and Technical Information of China (English)

    OU Xiuqin; LIU Shuguang; LIANG Guangchuan; LI Ying; ZHI Xiaoke; HAN Bin

    2006-01-01

    The effects of acetylene black powder surface free energy on air electrode electrochemical performance and lifetime were studied. The acetylene black was immersed in 30% H2O2 at room temperature and the changes of functional groups and surface free energy were investigated by X-ray Photoelectron Spectroscopy (XPS) and powder contact angle (CA). The air electrode performance was characterized by the potential polarization curves and the lifetime was measured by constant-current discharge. It shows that, its surface free energy is the lowest when the acetylene black is immersed in H2O2 for 240 h. The polarization potential of the air electrode prepared by the pretreated acetylene black is 0.25 V(vs. Hg/HgO), 0.21 V lower than the air electrode with untreated acetylene black when the working current density is 100 mA·cm-1 . And its lifetime is over 800 h at 80 mA·cm-1 . The pretreatment of acetylene black for proper time by H2O2 is favorable for the stability of the tri-phase reaction interface of air electrode and improvement of its performance.

  17. Geothermal: surface geothermal, low temperature geothermal, high temperature geothermal, stimulation-based high temperature geothermal

    International Nuclear Information System (INIS)

    For the different geothermal energy technologies (as a whole, surface, low temperature, high temperature, and stimulated high temperature), this document proposes: brief definitions and descriptions of principle and operation, challenges and stakes regarding energy production, major actors in the World in terms of installed power and in France in terms of committed organisations, measurement units and key figures, typical locations, past and present exploitation, and future perspectives. Thus technologies like heat pumps or Canadian well among others, their strengths and weaknesses, and their use in electricity production are evoked

  18. Sea surface temperature and torrential rains in the Valencia region: modelling the role of recharge areas

    Science.gov (United States)

    Pastor, Francisco J.

    2016-04-01

    Heavy rain events are frequently recorded in the Western Mediterranean causing economic and human losses. A main factor in the development of torrential rains is ocean-atmosphere exchange of heat and moisture that can destabilize air masses travelling over the sea. The study of air mass trajectories previous to the rain event permits the identification of sea areas that could probably contribute to the development or intensification of rainfall. From a Mediterranean sea surface temperature climatology, its spatio-temporal distribution patterns have been studied showing two main distribution modes in winter and summer and transitional regimes in spring and autumn. Hence, three heavy precipitation events, for such winter and summer sea temperature regimes and for fall transition, affecting the Valencia region have been selected to study the effect of sea surface temperature in torrential rains. Simulations with perturbed sea surface temperature in different areas along the air mass path were run to compare results with unperturbed simulation. The variation of sea surface temperature in certain areas caused significant changes in model accumulated values and its spatial distribution. Therefore, the existence of areas that at a greater extent favour air-sea interaction leading to the development of torrential rainfall in the Valencia region is shown. This methodology could be extended to other Mediterranean regions to look for such potential recharge areas. The identification of sea areas that contribute to the development or intensification of heavy rain events in the Mediterranean countries could be a useful prognosis and/or monitoring tool.

  19. PLS Road surface temperature forecast for susceptibility of ice occurrence

    Science.gov (United States)

    Marchetti, Mario; Khalifa, Abderrhamen; Bues, Michel

    2014-05-01

    Winter maintenance relies on many operational tools consisting in monitoring atmospheric and pavement physical parameters. Among them, road weather information systems (RWIS) and thermal mapping are mostly used by service in charge of managing infrastructure networks. The Data from RWIS and thermal mapping are considered as inputs for forecasting physical numerical models, commonly in place since the 80s. These numerical models do need an accurate description of the infrastructure, such as pavement layers and sub-layers, along with many meteorological parameters, such as air temperature and global and infrared radiation. The description is sometimes partially known, and meteorological data is only monitored on specific spot. On the other hand, thermal mapping is now an easy, reliable and cost effective way to monitor road surface temperature (RST), and many meteorological parameters all along routes of infrastructure networks, including with a whole fleet of vehicles in the specific cases of roads, or airports. The technique uses infrared thermometry to measure RST and an atmospheric probes for air temperature, relative humidity, wind speed and global radiation, both at a high resolution interval, to identify sections of the road network prone to ice occurrence. However, measurements are time-consuming, and the data from thermal mapping is one input among others to establish the forecast. The idea was to build a reliable forecast on the sole data from thermal mapping. Previous work has established the interest to use principal component analysis (PCA) on the basis of a reduced number of thermal fingerprints. The work presented here is a focus on the use of partial least-square regression (PLS) to build a RST forecast with air temperature measurements. Roads with various environments, weather conditions (clear, cloudy mainly) and seasons were monitored over several months to generate an appropriate number of samples. The study was conducted to determine the minimum

  20. Air Temperature Fields inside Refrigeration Cabins: A Comparison of Results from CFD and ANN modelling

    OpenAIRE

    Conceição António, C.; Afonso, C.F.

    2011-01-01

    Abstract In refrigerated spaces, the inside air is cooled by a heat sink operating either by forced or natural convection. The last situation is more frequently used in small apparatus, such as domestic household refrigerators. The inside air temperature is not usually monitored in these refrigerated spaces. Therefore, knowledge of the air temperature field inside of these units is limited and large air temperature gradients often exist that can put the stored products at risk. Thi...

  1. Exchange flux of total gaseous mercury between air and natural water surfaces in summer season

    Institute of Scientific and Technical Information of China (English)

    FENG; Xinbin; (冯新斌); Jonas; Sommar; Katarina; Gordfeldt; Oliver; Lindqvist

    2002-01-01

    The exchanges of mercury between surface and air are of significance in the biogeochemical cycling of Hg in the environment, but there are still few reliable data on air/surface exchange in aquatic systems. Field measurement campaigns over seawater surface at Kristineberg Marine Research Station (KMRS) and over Hovg?rds?n River surface at Knobesholm in southwestern Sweden were conducted to measure mercury flux using a dynamic flux chamber technique coupled with automatic mercury vapor-phase analyzers. Both sites show net emissions during summer time. Mercury fluxes measured over both river and seawater surfaces exhibit a consistently diurnal pattern with maximum fluxes during the daytime period and minimum fluxes during the nighttime period. At freshwater site, mercury flux is strongly correlated with the intensity of net solar radiation, and negatively correlated with relative humidity. A typical exponential relationship between mercury flux and water temperature was observed at freshwater measurement site. At seawater site, a strong correlation between mercury flux and intensity of solar radiation was obtained. The driving force of mercury emission from water surface to air is the super-saturation of dissolved gaseous mercury in aqueous phase.

  2. The effect of the partial pressure of water vapor on the surface tension of the liquid water-air interface.

    Science.gov (United States)

    Pérez-Díaz, José L; Álvarez-Valenzuela, Marco A; García-Prada, Juan C

    2012-09-01

    Precise measurements of the surface tension of water in air vs. humidity at 5, 10, 15, and 20 °C are shown. For constant temperature, surface tension decreases linearly for increasing humidity in air. These experimental data are in good agreement with a simple model based on Newton's laws here proposed. It is assumed that evaporating molecules of water are ejected from liquid to gas with a mean normal component of the speed of "ejection" greater than zero. A high humidity in the air reduces the net flow of evaporating water molecules lowering the effective surface tension on the drop. Therefore, just steam in air acts as an effective surfactant for the water-air interface. It can partially substitute chemical surfactants helping to reduce their environmental impact. PMID:22717083

  3. Surface Temperature Measurement Using Hematite Coating

    Science.gov (United States)

    Bencic, Timothy J. (Inventor)

    2015-01-01

    Systems and methods that are capable of measuring temperature via spectrophotometry principles are discussed herein. These systems and methods are based on the temperature dependence of the reflection spectrum of hematite. Light reflected from these sensors can be measured to determine a temperature, based on changes in the reflection spectrum discussed herein.

  4. The Microclimate in Protective Fire Fighter Footwear: Foot Temperature and Air Temperature and Relative Humidity

    Directory of Open Access Journals (Sweden)

    Irzmańska Emilia

    2016-06-01

    Full Text Available The study material consisted of two models of protective firefighter footwear. The tests were conducted on subjects in a laboratory using an ergometric treadmill. The parameters of footwear microclimate were continuously recorded using T/RH sensors. For the leather footwear, the highest foot temperature was recorded in the 50th minute of the experiment (35.8°C in the dorsal region and 37.3°C in the plantar region and for the polymer footwear in the 60th minute of the experiment (35.4°C in the dorsal region and 37.0°C in the plantar region. In the leather footwear, the temperature of the air surrounding the feet rose from 31.0°C to 35.4°C, and then declined, but did not return to the initial level during the rest period. In turn, in the polymer footwear, the temperature rose from 29.0 to 34.7°C, and then decreased to 33.7°C following the rest period. The highest relative air humidity was recorded in the polymer footwear (96.6%, while in the leather footwear it amounted to 91%. Testing the dynamics of the microclimate during footwear use provides complete information about changes in the temperature of the skin of the foot and the temperature and relative humidity of the footwear microclimate.

  5. A Comparison of Satellite Land Surface Temperature With Station Measured Temperature For Improved Detection of Frozen Ground

    Science.gov (United States)

    basnet, S.; Shahroudi, N.

    2013-12-01

    The transition of the landscape between frozen and non-frozen conditions in seasonally frozen environments impacts climate and is closely linked to surface energy budget, vegetation growing season dynamics, and hydrological, ecological, and biogeochemical processes. Frozen ground occurs when the ground contains water, and the temperature of the ground goes down below 0° Celsius. In seasonally frozen environments, by the end of winter air temperatures rise above freezing, the snow pack and surface soil layer reach 0° Celsius and begin to thaw, resulting in a state change of the included water from solid to liquid. Surface temperature is one of the main factors that detects the frozen ground. In this study the land surface temperature (LST) derived from infrared (IR) radiance at International Satellite Cloud Climatology Project (ISCCP) is compared to ground surface temperature (GST) measurements from Integrated Surface Database (ISD) at National Climatic Data Center (NCDC) for 25 consecutive years (1985-2004). The analysis between LST and GST show high correlation in terms of both time and location. The research was carried out over the entire globe to study the trend between fluctuating temperature and snow cover. Number of days with temperature below zero (freezing) and above zero (thawing) were counted over a 34-year period for the GST data. Over the time winter was classified from severe to mild due to an increase in temperature. The analysis showed 2% increase in surface temperature during winter seasons and there was a decrease in the number of days with frozen ground globally. LST offers a great potential for monitoring temperature changes and is a reliable source of data for frozen ground detection.

  6. Effective surface impedance of a high temperature superconductor

    International Nuclear Information System (INIS)

    Highlights: •Effective surface impedance depends on London penetration depth and operating temperature, T. •The effective surface resistance and the effective surface reactance are important. •The surface resistance determines the electromagnetic power dissipation. -- Abstract: In this work, we will investigate theoretically the effective surface impedance of a high temperature superconducting thin film in the microwave range. This investigation will be according to varying the thickness of the superconducting thin film and the operating temperature, based on means of impedance transformations. The microwave surface impedance is related to the fundamental properties of high-Tc superconductors. The study of surface impedance has two important aspects. The first one is the real part of the surface impedance; the surface resistance determines the electromagnetic power dissipation through the superconductor thin film. The second is the imaginary part of the surface impedance; the surface reactance is proportional to the magnetic-field penetration depth

  7. Effective surface impedance of a high temperature superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Aly, Arafa H., E-mail: arafa16@yahoo.com; Sabra, Walied

    2013-12-15

    Highlights: •Effective surface impedance depends on London penetration depth and operating temperature, T. •The effective surface resistance and the effective surface reactance are important. •The surface resistance determines the electromagnetic power dissipation. -- Abstract: In this work, we will investigate theoretically the effective surface impedance of a high temperature superconducting thin film in the microwave range. This investigation will be according to varying the thickness of the superconducting thin film and the operating temperature, based on means of impedance transformations. The microwave surface impedance is related to the fundamental properties of high-T{sub c} superconductors. The study of surface impedance has two important aspects. The first one is the real part of the surface impedance; the surface resistance determines the electromagnetic power dissipation through the superconductor thin film. The second is the imaginary part of the surface impedance; the surface reactance is proportional to the magnetic-field penetration depth.

  8. Temperature profile and producer gas composition of high temperature air gasification of oil palm fronds

    International Nuclear Information System (INIS)

    Environmental pollution and scarcity of reliable energy source are the current pressing global problems which need a sustainable solution. Conversion of biomass to a producer gas through gasification process is one option to alleviate the aforementioned problems. In the current research the temperature profile and composition of the producer gas obtained from the gasification of oil palm fronds by using high temperature air were investigated and compared with unheated air. By preheating the gasifying air at 500°C the process temperature were improved and as a result the concentration of combustible gases and performance of the process were improved. The volumetric percentage of CO, CH4 and H2 were improved from 22.49, 1.98, and 9.67% to 24.98, to 2.48% and 13.58%, respectively. In addition, HHV, carbon conversion efficiency and cold gas efficiency were improver from 4.88 MJ/Nm3, 83.8% and 56.1% to 5.90 MJ/Nm3, 87.3% and 62.4%, respectively.

  9. Trend analysis of air temperature and precipitation time series over Greece: 1955-2010

    Science.gov (United States)

    Marougianni, G.; Melas, D.; Kioutsioukis, I.; Feidas, H.; Zanis, P.; Anandranistakis, E.

    2012-04-01

    In this study, a database of air temperature and precipitation time series from the network of Hellenic National Meteorological Service has been developed in the framework of the project GEOCLIMA, co-financed by the European Union and Greek national funds through the Operational Program "Competitiveness and Entrepreneurship" of the Research Funding Program COOPERATION 2009. Initially, a quality test was applied to the raw data and then missing observations have been imputed with a regularized, spatial-temporal expectation - maximization algorithm to complete the climatic record. Next, a quantile - matching algorithm was applied in order to verify the homogeneity of the data. The processed time series were used for the calculation of temporal annual and seasonal trends of air temperature and precipitation. Monthly maximum and minimum surface air temperature and precipitation means at all available stations in Greece were analyzed for temporal trends and spatial variation patterns for the longest common time period of homogenous data (1955 - 2010), applying the Mann-Kendall test. The majority of the examined stations showed a significant increase in the summer maximum and minimum temperatures; this could be possibly physically linked to the Etesian winds, because of the less frequent expansion of the low over the southeastern Mediterranean. Summer minimum temperatures have been increasing at a faster rate than that of summer maximum temperatures, reflecting an asymmetric change of extreme temperature distributions. Total annual precipitation has been significantly decreased at the stations located in western Greece, as well as in the southeast, while the remaining areas exhibit a non-significant negative trend. This reduction is very likely linked to the positive phase of the NAO that resulted in an increase in the frequency and persistence of anticyclones over the Mediterranean.

  10. AirSWOT: An Airborne Platform for Surface Water Monitoring

    Science.gov (United States)

    Rodriguez, E.; Moller, D.; Smith, L. C.; Pavelsky, T. M.; Alsdorf, D. E.

    2010-12-01

    The SWOT mission, expected to launch in 2020, will provide global measurements of surface water extent and elevation from which storage change and discharge can be derived. SWOT-like measurements are not routinely used by the hydrology community, and their optimal use and associated errors are areas of active research. The purpose of AirSWOT, a system that has been proposed to NASA’s Instrument Incubator Program, is to provide SWOT-like measurements to the hydrology and ocean community to be used to advance the understanding and use of SWOT data in the pre-launch phase. In the post-launch phase, AirSWOT will be used as the SWOT calibration/validation platform. The AirSWOT payload will consist of Kaspar, a multi-beam Ka-band radar interferometer able to produce elevations over a 5 km swath with centimetric precision. The absolute elevation accuracy of the AirSWOT system will be achieved with a combination of high precision Inertial Motion Units (IMUs), ground calibration points, and advanced calibration techniques utilizing a priori knowledge. It is expected that the accuracy of AirSWOT will exceed or match SWOT’s accuracy requirements. In addition to elevation measurements, the AirSWOT payload will include a near-infrared camera able to provide coincident high-resolution optical imagery of the water bodies imaged by the radar. In its initial hydrology deployments, AirSWOT will investigate four field sites: the Ohio-Mississippi confluence, the lower Atchafalaya River on the Mississippi River Delta, the Yukon River basin near Fairbanks, and the Sacramento River, California. The Ohio-Mississippi confluence is targeted for its large discharge, modest slope, and control structures that modulate Ohio but not Mississippi River slopes and elevations. The lower Atchafalaya River includes low slopes, wetlands with differing vegetation types, and some open lakes. Vegetation includes Cyprus forests, floating macrophytes, and grass marshes, all of which impact radar returns

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

    Directory of Open Access Journals (Sweden)

    Milovanović Boško

    2009-01-01

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

  12. Thermodynamic diagrams for high temperature plasmas of air, air-carbon, carbon-hydrogen mixtures, and argon

    CERN Document Server

    Kroepelin, H; Hoffmann, K-U

    2013-01-01

    Thermodynamic Diagrams for High Temperature Plasmas of Air, Air-Carbon, Carbon-Hydrogen Mixtures, and Argon provides information relating to the properties of equilibrium gas plasmas formed from hydrocarbons, from air without argon, from pure argon, and from mixtures of air and carbon at various compositions, temperatures and pressures. The data are presented in graphical rather than tabular form to provide a clearer picture of the plasma processes investigated. This book is composed of four chapters, and begins with the introduction to the characteristics of plasmas, with emphasis on their th

  13. Influence of Cooling to Heating Load Ratio on Optimal Supply Water and Air Temperatures in an Air Conditioning System

    Science.gov (United States)

    Karino, Naoki; Shiba, Takashi; Yokoyama, Ryohei; Ito, Koichi

    In planning an air conditioning system, supply water and air temperatures are important factors from the viewpoint of energy saving and cost reduction. For example, lower temperature supply water and air for space cooling reduce the coefficient of performance of a refrigeration machine, and increase the thickness of heat insulation material. However, they enable larger temperature differences, and reduce equipment sizes and power demand. It is also an important subject to evaluate the effect of the supply water and air temperatures on energy saving and cost reduction on the annual basis by considering not only cooling but also heating loads. The purposes of this paper are to propose an optimal planning method for an air conditioning system with large temperature difference, and to analyze the effect of supply water and air temperatures on the long-term economics through a numerical study for an office building. As a result, it is shown that the proposed method effectively determines supply water and air temperatures, and the influence of the cooling to heating load ratio on the long-term economics is clarified.

  14. Technique for the estimation of surface temperatures from embedded temperature sensing for rapid, high energy surface deposition.

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, Tyson R.; Schunk, Peter Randall; Roberts, Scott Alan

    2014-07-01

    Temperature histories on the surface of a body that has been subjected to a rapid, highenergy surface deposition process can be di cult to determine, especially if it is impossible to directly observe the surface or attach a temperature sensor to it. In this report, we explore two methods for estimating the temperature history of the surface through the use of a sensor embedded within the body very near to the surface. First, the maximum sensor temperature is directly correlated with the peak surface temperature. However, it is observed that the sensor data is both delayed in time and greatly attenuated in magnitude, making this approach unfeasible. Secondly, we propose an algorithm that involves tting the solution to a one-dimensional instantaneous energy solution problem to both the sensor data and to the results of a one-dimensional CVFEM code. This algorithm is shown to be able to estimate the surface temperature 20 C.

  15. Temporal variability of remotely sensed suspended sediment and sea surface temperature patterns in Mobile Bay, Alabama

    Science.gov (United States)

    Rucker, J.B.; Stumpf, R.P.; Schroeder, W.W.

    1990-01-01

    Distribution patterns of suspended sediments and sea surface temperatures in, Mobile Bay were derived from algorithms using digital data from the visible, near infrared, and infrared channels of the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-TIROS-N satellite. Closely spaced AVHRR scenes for January 20, 24, and 29, 1982, were compared with available environmental information taken during the same period. A complex interaction between river discharge, winds, and astronomical tides controlled the distribution patterns of suspended sediments. These same variables, coupled with air temperatures, also governed the distribution patterns of sea surface temperatures. ?? 1990 Estuarine Research Federation.

  16. Estimation of sea surface temperature (SST) using marine seismic data

    Digital Repository Service at National Institute of Oceanography (India)

    Sinha, S.K.; Dewangan, P.; Sain, K.

    diurnal variation in temperature. Keywords: Marine Seismic; Direct Arrivals; Soundspeed; Sea Surface Temperature; Diurnal variations. 2 INTRODUCTION Properties of sound waves in oceans are governed by temperature, salinity, water composition... understand ocean dynamics, researchers in the field of ocean acoustics invert for temperature and salinity from observed sound waves, whereas oceanographers measure governing parameters directly by deploying devices such as Expendable Bathythermographs...

  17. Evaluation of entrance surface air kerma in pediatric chest radiography

    International Nuclear Information System (INIS)

    The objective of this study was to evaluate the entrance surface air kerma in pediatric chest radiography. An evaluation of 301 radiographical examinations in anterior–posterior (AP) and posterior–anterior (PA) (166 examinations) and lateral (LAT) (135 examinations) projections was performed. The analyses were performed on patients grouped by age; the groups included ages 0–1 y, 1–5 y, 5–10 y, and 10–15 y. The entrance surface air kerma was determined with DoseCal software (Radiological Protection Center of Saint George's Hospital, London) and thermoluminescent dosimeters. Two different exposure techniques were compared. The doses received by patients who had undergone LAT examinations were 40% higher, on average, those in AP/PA examinations because of the difference in tube voltage. A large high-dose “tail” was observed for children up to 5 y old. An increase in tube potential and corresponding decrease in current lead to a significant dose reduction. The difference between the average dose values for different age ranges was not practically observed, implying that the exposure techniques are still not optimal. Exposure doses received using the higher tube voltage and lower current-time product correspond to the international diagnostic reference levels. - Highlights: • The entrance surface air kerma of chest X-ray examinations in pediatric patients was estimated. • The data were analyzed for patients aged up to 15 y, stratified by age. • The doses of LAT examinations were 40% higher than of AP/PA because of kV used. • An increase in kV with a decrease in mAs leads to significant dose reduction

  18. Reconnoitering the effect of shallow groundwater on land surface temperature and surface energy balance using MODIS and SEBS

    Directory of Open Access Journals (Sweden)

    F. Alkhaier

    2011-09-01

    Full Text Available The possibility of observing shallow groundwater depth and areal extent using satellite measurements can support groundwater models and vast irrigation systems management. Besides, these measurements help bringing groundwater effect on surface energy balance within land surface models and climate studies. To inspect the MODIS capacity of detecting shallow groundwater effect on land surface temperature and surface energy balance in an area within Al-Balikh River basin in northern Syria, we investigated the interrelationship between in-situ measured water table depths and land surface temperatures of MODIS. Further, we used the Surface Energy Balance System (SEBS to calculate surface energy fluxes, evaporative fraction and daily evaporation, and inspected their relationships with water table depths. In agreement with the findings of a companion paper (Alkhaier et al., 2011, we found that daytime temperature increased and nighttime temperature decreased with increasing water table depth. Where water table depth increased, net radiation, latent and ground heat fluxes, evaporative fraction and daily evaporation decreased, while sensible heat flux increased. The clear observed relationships resulted from meeting both conditions concluded in the companion paper, i.e. high potential evaporation and big contrast in air temperature. Moreover, the prevailing conditions in this study area helped SEBS producing accurate estimates. We conclude that MODIS is suitable for shallow groundwater effect detection since it has proper imaging times and appropriate sensor accuracy; nevertheless, its coarse spatial resolution is disadvantageous.

  19. Some Physical and Computational Issues in Land Surface Data Assimilation of Satellite Skin Temperatures

    Science.gov (United States)

    Mackaro, Scott M.; McNider, Richard T.; Biazar, Arastoo Pour

    2012-03-01

    Skin temperatures that reflect the radiating temperature of a surface observed by infrared radiometers are one of the most widely available products from polar orbiting and geostationary satellites and the most commonly used satellite data in land surface assimilation. Past work has indicated that a simple land surface scheme with a few key parameters constrained by observations such as skin temperatures may be preferable to complex land use schemes with many unknown parameters. However, a true radiating skin temperature is sometimes not a prognostic variable in weather forecast models. Additionally, recent research has shown that skin temperatures cannot be directly used in surface similarity forms for inferring fluxes. This paper examines issues encountered in using satellite derived skin temperatures to improve surface flux specifications in weather forecast and air quality models. Attention is given to iterations necessary when attempting to nudge the surface energy budget equation to a desired state. Finally, the issue of mathematical operator splitting is examined in which the surface energy budget calculations are split with the atmospheric vertical diffusion calculations. However, the high level of connectivity between the surface and first atmospheric level means that the operator splitting leads to high frequency oscillations. These oscillations may hinder the assimilation of skin temperature derived moisture fluxes.

  20. Global surface temperatures and the atmospheric electrical circuit

    Science.gov (United States)

    Price, Colin

    1993-01-01

    To monitor future global temperature trends, it would be extremely useful if parameters nonlinearly related to surface temperature could be found, thereby amplifying any warming signal that may exist. Evidence that global thunderstorm activity is nonlinearly related to diurnal, seasonal and interannual temperature variations is presented. Since global thunderstorm activity is also well correlated with the earth's ionospheric potential, it appears that variations of ionospheric potential, that can be measured at a single location, may be able to supply valuable information regarding global surface temperature fluctuations. The observations presented enable a prediction that a 1 percent increase in global surface temperatures may result in a 20 percent increase in ionospheric potential.

  1. A hybrid model for river water temperature as a function of air temperature and discharge

    International Nuclear Information System (INIS)

    Water temperature controls many biochemical and ecological processes in rivers, and theoretically depends on multiple factors. Here we formulate a model to predict daily averaged river water temperature as a function of air temperature and discharge, with the latter variable being more relevant in some specific cases (e.g., snowmelt-fed rivers, rivers impacted by hydropower production). The model uses a hybrid formulation characterized by a physically based structure associated with a stochastic calibration of the parameters. The interpretation of the parameter values allows for better understanding of river thermal dynamics and the identification of the most relevant factors affecting it. The satisfactory agreement of different versions of the model with measurements in three different rivers (root mean square error smaller than 1oC, at a daily timescale) suggests that the proposed model can represent a useful tool to synthetically describe medium- and long-term behavior, and capture the changes induced by varying external conditions. (letter)

  2. MODIS-based air temperature estimation in the southeastern Tibetan Plateau and neighboring areas

    Institute of Scientific and Technical Information of China (English)

    YAO Yonghui; ZHANG Baiping

    2012-01-01

    Climatic conditions are difficult to obtain in high mountain regions due to few meteorological stations and,if any,their poorly representative location designed for convenient operation.Fortunately,it has been shown that remote sensing data could be used to estimate near-surface air temperature (Ta) and other climatic conditions.This paper makes use of recorded meteorological data and MODIS data on land surface temperature (Ts) to estimate monthly mean air temperatures in the southeastern Tibetan Plateau and its neighboring areas.A total of 72 weather stations and 84 MODIS images for seven years (2001 to 2007) are used for analysis.Regression analysis and spatio-temporal analysis of monthly mean Ts vs.monthly mean Ta are carried out,showing that recorded Ta is closely related to MODIS Ts in the study region.The regression analysis of monthly mean Ts vs.Ta for every month of all stations shows that monthly mean Ts can be rather accurately used to estimate monthly mean Ta (R2 ranging from 0.62 to 0.90 and standard error between 2.25 ℃ and 3.23℃).Thirdly,the retrieved monthly mean Ta for the whole study area varies between 1.62℃ (in January,the coldest month) and 17.29 ℃ (in July,the warmest month),and for the warm season (May-September),it is from 13.1 ℃ to 17.29℃.Finally,the elevation of isotherms is higher in the central mountain ranges than in the outer margins; the 0℃ isotherm occurs at elevation of about 4500±500 m in October,dropping to 3500±500 m in January,and ascending back to 4500±500 m in May next year.This clearly shows that MODIS Ts data combining with observed data could be used to rather accurately estimate air temperature in mountain regions.

  3. Sea surface temperature anomalies along the Black Sea Region coast of Turkey (1971-2010 period)

    OpenAIRE

    Yüksel Güçlü

    2013-01-01

    The aim of this study is finding an answer to a question how the development and change of sea surface temperature (SST) anomalies were at the Black Sea Region in Turkey between 1971 and 2010. For that purpose, SST data of Amasra, Inebolu, Sinop, Samsun, Ordu, Giresun and Hopa stations were used. Air temperature is meteorological element having a clearest effect on annual and seasonal SST anomalies. Also in winter North Atlantic Oscillation (NAO) and North Sea Hazar Pattern (NCP) and in sprin...

  4. MODIS-based estimation of air temperature of the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    YAO Yonghui; ZHANG Baiping

    2013-01-01

    The immense and towering Tibetan Plateau acts as a heating source and,thus,deeply shapes the climate of the Eurasian continent and even the whole world.However,due to the scarcity of meteorological observation stations and very limited climatic data,little is quantitatively known about the heating effect and temperature pattern of the Tibetan Plateau.This paper collected time series of MODIS land surface temperature (LST) data,together with meteorological data of 137 stations and ASTER GDEM data for 2001-2007,to estimate and map the spatial distribution of monthly mean air temperatures in the Tibetan Plateau and its neighboring areas.Time series analysis and both ordinary linear regression (OLS) and geographical weighted regression (GWR) of monthly mean air temperature (Ta) with monthly mean land surface temperature (Ts) were conducted.Regression analysis shows that recorded Ta is rather closely related to Ts,and that the GWR estimation with MODIS Ts and altitude as independent variables,has a much better result with adjusted R2 > 0.91 and RMSE =1.13-1.53℃ than OLS estimation.For more than 80% of the stations,the Ta thus retrieved from Ts has residuals lower than 2℃.Analysis of the spatio-temporal pattern of retrieved Ta data showed that the mean temperature in July (the warmest month) at altitudes of 4500 m can reach 10℃.This may help explain why the highest timberline in the Northern Hemisphere is on the Tibetan Plateau.

  5. Low Temperature Drying With Air Dehumidified by Zeolite for Food Products: Energy Efficiency Aspect Analysis

    OpenAIRE

    M. Djaeni; Asselt, van, R.; Bartels, P.V.; Sanders, J. P. M.; Straten, van, FE; Boxtel, van, C.

    2011-01-01

    Developments in low temperature drying of food products are still an interesting issue; especially with respect to the energy efficiency. This research studies the energy efficiency that can be achieved by a dryer using air which is dehumidified by zeolite. Experimental results are fitted to a dynamic model to find important variables for the drying operation. The results show that ambient air temperature as well as the ratio between air flow for drying and air flow for regeneration, affect t...

  6. Implant Surface Temperature Changes during Er:YAG Laser Irradiation with Different Cooling Systems.

    Directory of Open Access Journals (Sweden)

    Abbas Monzavi

    2014-04-01

    Full Text Available Peri-implantitis is one of the most common reasons for implant failure. Decontamination of infected implant surfaces can be achieved effectively by laser irradiation; although the associated thermal rise may cause irreversible bone damage and lead to implant loss. Temperature increments of over 10ºC during laser application may suffice for irreversible bone damage.The purpose of this study was to evaluate the temperature increment of implant surface during Er:YAG laser irradiation with different cooling systems.Three implants were placed in a resected block of sheep mandible and irradiated with Er:YAG laser with 3 different cooling systems namely water and air spray, air spray alone and no water or air spray. Temperature changes of the implant surface were monitored during laser irradiation with a K-type thermocouple at the apical area of the fixture.In all 3 groups, the maximum temperature rise was lower than 10°C. Temperature changes were significantly different with different cooling systems used (P<0.001.Based on the results, no thermal damage was observed during implant surface decontamination by Er:YAG laser with and without refrigeration. Thus, Er:YAG laser irradiation can be a safe method for treatment of periimplantitis.

  7. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Science.gov (United States)

    2010-07-01

    ... temperature corrections. 1065.670 Section 1065.670 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX...

  8. Historical underway surface temperature data collected aboard the ship Skelton Castle on a voyage from England to India, 28 February 1800 to 3 June 1800 (NODC Accession 0095925)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Underway surface air temperature and sea water temperature were collected aboard the Skelton Castle while in route from England to Bombay India as part of the East...

  9. Degradation mechanism of amorphous silicon carbide fiber due to air-exposure at high temperatures

    International Nuclear Information System (INIS)

    The degradation mechanism of the amorphous silicon carbide fiber, Tyranno-ZMI, exposed in air at 1173-1873 K for 20 ks were studied. The average strength of the bare fiber, which was prepared by etching away the oxidation layer on the fiber surface, decreased with increasing exposure temperature, especially when exposed at the temperature higher than 1673 K. The measurement of the crystallite size of β-SiC in the fiber with Sherrer method revealed that coarsening of the crystalline occurred in the fiber exposed at the temperatures higher than 1773 K. The scanning electron microscope observation of the fiber surface showed that the many defects formed on the fiber surface. By introducing an artificial notch directly into the fiber specimens using a focused-ion(Ga+)-beam, the fracture toughness values of the as-supplied fiber and of the fiber exposed at 1673 and 1773 K were determined to be 1.8±0.3, 1.9±0.4 and 1.3±0.4 MPa √m, respectively. Based on these results, the reason for the degradation of the fiber was attributed to the extension of the surface defect which was enhanced by the reduction in fracture toughness due to coarsening of the β-SiC crystalline. (author)

  10. Lubricant-infused micro/nano-structured surfaces with tunable dynamic omniphobicity at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, Daniel; Max, Mankin N.; Belisle, Rebecca A.; Wong, Tak-Sing; Aizenberg, Joanna

    2013-06-12

    Omniphobic surfaces that can repel fluids at temperatures higher than 100 °C are rare. Most stateof- the-art liquid-repellent materials are based on the lotus effect, where a thin air layer is maintained throughout micro/nanotextures leading to high mobility of liquids. However, such behavior eventually fails at elevated temperatures when the surface tension of test liquids decreases significantly. Here, we demonstrate a class of lubricant-infused structured surfaces that can maintain a robust omniphobic state even for low-surface-tension liquids at temperatures up to at least 200 °C. We also demonstrate how liquid mobility on such surfaces can be tuned by a factor of 1000.

  11. Lubricant-infused micro/nano-structured surfaces with tunable dynamic omniphobicity at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, D; Mankin, MN; Belisle, RA; Wong, TS; Aizenberg, J

    2013-06-10

    Omniphobic surfaces that can repel fluids at temperatures higher than 100 degrees C are rare. Most state-of-the-art liquid-repellent materials are based on the lotus effect, where a thin air layer is maintained throughout micro/nanotextures leading to high mobility of liquids. However, such behavior eventually fails at elevated temperatures when the surface tension of test liquids decreases significantly. Here, we demonstrate a class of lubricant-infused structured surfaces that can maintain a robust omniphobic state even for low-surface-tension liquids at temperatures up to at least 200 degrees C. We also demonstrate how liquid mobility on such surfaces can be tuned by a factor of 1000. (C) 2013 Author(s).

  12. Lubricant-infused micro/nano-structured surfaces with tunable dynamic omniphobicity at high temperatures

    Science.gov (United States)

    Daniel, Daniel; Mankin, Max N.; Belisle, Rebecca A.; Wong, Tak-Sing; Aizenberg, Joanna

    2013-06-01

    Omniphobic surfaces that can repel fluids at temperatures higher than 100 °C are rare. Most state-of-the-art liquid-repellent materials are based on the lotus effect, where a thin air layer is maintained throughout micro/nanotextures leading to high mobility of liquids. However, such behavior eventually fails at elevated temperatures when the surface tension of test liquids decreases significantly. Here, we demonstrate a class of lubricant-infused structured surfaces that can maintain a robust omniphobic state even for low-surface-tension liquids at temperatures up to at least 200 °C. We also demonstrate how liquid mobility on such surfaces can be tuned by a factor of 1000.

  13. Core and body surface temperatures of nesting leatherback turtles (Dermochelys coriacea).

    Science.gov (United States)

    Burns, Thomas J; McCafferty, Dominic J; Kennedy, Malcolm W

    2015-07-01

    Leatherback turtles (Dermochelys coriacea) are the largest species of marine turtle and the fourth most massive extant reptile. In temperate waters they maintain body temperatures higher than surrounding seawater through a combination of insulation, physiological, and behavioural adaptations. Nesting involves physical activity in addition to contact with warm sand and air, potentially presenting thermal challenges in the absence of the cooling effect of water, and data are lacking with which to understand their nesting thermal biology. Using non-contact methods (thermal imaging and infrared thermometry) to avoid any stress-related effects, we investigated core and surface temperature during nesting. The mean±SE core temperature was 31.4±0.05°C (newly emerged eggs) and was not correlated with environmental conditions on the nesting beach. Core temperature of leatherbacks was greater than that of hawksbill turtles (Eretmochelys imbricata) nesting at a nearby colony, 30.0±0.13°C. Body surface temperatures of leatherbacks showed regional variation, the lateral and dorsal regions of the head were warmest while the carapace was the coolest surface. Surface temperature increased during the early nesting phases, then levelled off or decreased during later phases with the rates of change varying between body regions. Body region, behavioural phase of nesting and air temperature were found to be the best predictors of surface temperature. Regional variation in surface temperature were likely due to alterations in blood supply, and temporal changes in local muscular activity of flippers during the different phases of nesting. Heat exchange from the upper surface of the turtle was dominated by radiative heat loss from all body regions and small convective heat gains to the carapace and front flippers. PMID:25965013

  14. Some Characteristics of the Surface Boundary Layer of a Strong Cold Air Process over Southern China

    Institute of Scientific and Technical Information of China (English)

    LIU Ximing; CHENG Xueling; WU Qiong; FU Minning; ZENG Qingcun

    2013-01-01

    In southern China,cold air is a common weather process during the winter soason; it can cause strong wind,sharp temperature decreases,and even the snow or freezing rain events.However,the features of the atmospheric boundary layer during cold air passage are not clearly understood due to the lack of comprehensive observation data,especially regarding turbulence.In this study,four-layer gradient meteorological observation data and one-layer.10-Hz ultrasonic anemometer-thermometer monitoring data from the northeru side of Poyang Lake were employed to study the main features of the surface boundary layer during a strong cold-air passagc over southern China.The results show that,with the passage of a cold air front.the wind speed exhibits low-frequency variations and that the wind systematically descends.During the strong wind period,the wind speed increases with height in the surface layer.Regular gust packets arc superimposed on the basic strong wind flow.Before the passage of cold air,the wind gusts exhibit a coherent structure.The wind and turbulent momentum fluxes are small,although the gusty wind momentum flux is slightly larger than the turbulent momentum flux.However,during the invasion of cold air,both the gusty wind and turbulent momentum fluxes increase rapidly with wind speed,and the turbulent momentum flux is larger than the gusty wind momentum flux during the strong wind period.After the cold air invasion,this structure almost disappears.

  15. Effects of elevated air temperature on physiological characteristics of flag leaves and grain yield in rice

    OpenAIRE

    Liu Qi-Hua; Wu Xiu; Li Tian; Ma Jia-Qing; Zhou Xue-Biao

    2013-01-01

    As an indispensable environment element for crop growth, air temperature has brought challenge for the sustainable development of rice (Oryza sativa L.) production. Elevated air temperature led to great loss in rice grain yield in many districts suffering from heat stress due to the greenhouse effect worldwide, which has received more and more attention from researchers. A field experiment was conducted to investigate impacts of high air temperature (HAT) after rice heading stage on dynamics ...

  16. Diatom attachment inhibition: limiting surface accessibility through air entrapment.

    Science.gov (United States)

    Wu, Alex H-F; Nakanishi, Kenichi; Cho, K L; Lamb, Robert

    2013-12-01

    Surfaces consisting of sub micron holes (0.420-0.765 μm) engineered into nanoparticle (12 nm) coatings were examined for marine antifouling behaviour that defines early stage settlement. Immersed surfaces were found to be resistant to a 5-hour attachment assay of Amphora coffeaeformis, a marine organism commonly found in abundance on fouled substrates such as foul-releasing paints and self-polishing coatings. Attachment inhibition was attributed to the accessibility of diatoms to the surface. This was governed by the size and morphology of trapped interfacial air pockets measured in-situ using synchrotron small angle x-ray scattering. Surfaces containing larger pores (0.765 μm) exhibited the highest resistance. Macroscopic wettability via contact angle measurements however remained at 160° and sliding angle of < 5° and was found to be independent of pore size and not indicative of early stage fouling behaviour. The balance of hierarchical nano/micro length scales was critical in defining the early stage stability of biofouling character of the interface. PMID:24706117

  17. Seasonal variation of surface temperature based on land cover in Ankara

    Directory of Open Access Journals (Sweden)

    İhsan Çiçek

    2013-03-01

    Full Text Available In this study, the seasonal variation of the surface temperature of Ankara urban area and its enviroment have been analyzed by using Landsat 7 image. The Landsat 7 images of each month from 2007 to 2011 have been used to analyze the annually changes of the surface temperature. The land cover of the research area was defined with supervised classification method on the basis of the satellite image belonging to 2008 July. After determining the surface temperatures from 6-1 bands of satellite images, the monthly mean surface temperatures were calculated for land cover classification for the period between 2007 and 2011. Accordşng to the results obtained, the surface temperatures are high in summer and low in winter from the air temperatures. all satellite images were taken at 10:00 am, it is found that urban areas are cooler than rural areas at 10:00 am. Regarding the land cover classification, the water surfaces are the coolest surfaces during the whole year. The warmest areas are the grasslands and dry farming areas. While the parks are warmer than the urban areas during the winter, during the summer they are cooler than artificial land covers. The urban areas with higher building density are the cooler surfaces after water bodies.

  18. A dynamic model and an experimental study for the internal air and soil temperatures in an innovative greenhouse

    International Nuclear Information System (INIS)

    Highlights: • Simulation model for internal Greenhouse temperature including soil reflectance. • Greenhouse soil heat exchange affects internal temperature by approximately 12%. • Solar air heaters as greenhouse roof maintain better internal temperature year round. - Abstract: An innovative greenhouse which integrates a conventional greenhouse with roof mounted solar air heaters is used in this investigation. This design reduces the solar radiation incoming to the greenhouse in summer which reduced the load and cost of greenhouse cooling and provides a means of solar heating. Experimental measurements of the internal air and internal soil sub-layer temperatures in the greenhouse, without crops, were performed in Baghdad University, Baghdad, Iraq (33.3 °N, 44.4 °E). Measurements were recorded for clear and partly cloudy winter days. A dynamic model was developed to predict the all internal temperatures of the greenhouse. This model includes soil surface heat exchange with the greenhouse air which was found to give a more accurate prediction of the internal temperatures. Soil surface heat exchange has a positive contribution to the internal environment. The input parameters of the model were the measured meteorological conditions and the thermo-physical properties of the greenhouse components which include the cover, inside air, and soil. Comparisons between the predicted and measured results show good agreement. Also, results show that soil sub-layers inside the greenhouse at 50 cm depth are the best place for heat storage elements. The integrated system rendered maximum differences between ambient and internal air temperatures of 16 °C in February and 10 °C in June without operating any heating or cooling system

  19. Air-ground temperature coupling and subsurface propagation of annual temperature signals

    Czech Academy of Sciences Publication Activity Database

    Smerdon, J. E.; Pollack, H. N.; Čermák, Vladimír; Enz, J. W.; Krešl, Milan; Šafanda, Jan; Wehmiller, J. F.

    2004-01-01

    Roč. 109, D21 (2004), D21107/1-10. ISSN 0148-0227 R&D Projects: GA AV ČR KSK3046108; GA MŠk(CZ) 1P05ME778 Grant ostatní: NSF(US) ATM-0081864; NSF(US) EAR9315052; NASA(US) GWEC 0000 0132 Institutional research plan: CEZ:AV0Z3012916 Keywords : heat transport * air-ground temperature coupling * paleoclimate Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.839, year: 2004

  20. Metal surface temperature induced by moving laser beams

    NARCIS (Netherlands)

    Römer, G.R.B.E.; Meijer, J.

    1995-01-01

    Whenever a metal is irradiated with a laser beam, electromagnetic energy is transformed into heat in a thin surface layer. The maximum surface temperature is the most important quantity which determines the processing result. Expressions for this maximum temperature are provided by the literature fo

  1. Predicting monsoon rainfall and pressure indices from sea surface temperature

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.

    The relationship between the sea surface temperature (SST) in the Indian Ocean and monsoon rainfall has been examined by using 21 years data set (1967-87) of MOHSST.6 (Met. Office Historical Sea Surface Temperature data set, obtained from U.K. Met...

  2. Direct numerical simulation of a turbulent stably stratified air flow above a wavy water surface

    Science.gov (United States)

    Druzhinin, O. A.; Troitskaya, Yu. I.; Zilitinkevich, S. S.

    2016-01-01

    The influence of the roughness of the underlaying water surface on turbulence is studied in a stably stratified boundary layer (SSBL). Direct numerical simulation (DNS) is conducted at various Reynolds (Re) and Richardson (Ri) numbers and the wave steepness ka. It is shown that, at constant Re, the stationary turbulent regime is set in at Ri below the threshold value Ri c depending on Re. At Ri > Ri c , in the absence of turbulent fluctuations near the wave water surface, three-dimensional quasiperiodical structures are identified and their threshold of origin depends on the steepness of the surface wave on the water surface. This regime is called a wave pumping regime. The formation of three-dimensional structures is explained by the development of parametric instability of the disturbances induced by the surface water in the air flow. The DNS results are quite consistent with prediction of the theoretical model of the SSBL flow, in which solutions for the disturbances of the fields of velocity and temperature in the wave pumping regime are found to be a solution of a two-dimensional linearized system with the heterogeneous boundary condition, which is caused by the presence of the surface wave. In addition to the turbulent fluctuations, the three-dimensional structures in the wave pumping regime provide for the transfer of impulse and heat, i.e., the increase in the roughness of the water-air boundary caused by the presence of waves intensifies the exchange in the SSBL.

  3. Atomic oxygen recombination on the ODS PM 1000 at high temperature under air plasma

    International Nuclear Information System (INIS)

    High temperature materials are necessary for the design of primary heat shields for future reusable space vehicles re-entering atmospheric planet at hypersonic velocity. During the re-entry phase on earth, one of the most important phenomena occurring on the heat shield is the recombination of atomic oxygen and this phenomenon is more or less catalyzed by the material of the heat shield. PM 1000 is planned to be use on the EXPERT capsule to study in real conditions its catalycity. Before the flight, it is necessary to perform measurements on ground test facility. Experimental data of the recombination coefficient of atomic oxygen under air plasma flow were obtained in the diffusion reactor MESOX on pre-oxidized PM 1000, for two total pressures 300 and 1000 Pa in the temperature range (850-1650 K) using actinometry and optical emission spectroscopy. In this investigation, the evolution of the recombination coefficient is dependent of temperature, pressure level and also of the chemical composition of the surface leading to one order of magnitude for a given temperature. The recombination coefficient is increasing with temperature and also dependent on the static pressure. The surface change due to the plasma exposure is inspected with SEM, XRD and XPS. As chromium oxide is the main part of the oxide layer formed during the oxidation in air plasma conditions, a sintered Cr2O3 sample was elaborated from powders to compare the data of the recombination coefficient obtained on PM 1000. Pre- and post-test analyses on the several materials were carried out using SEM, WDS, XRD and XPS.

  4. Regional ground surface temperature mapping from meteorological data

    Science.gov (United States)

    Signorelli, S.; Kohl, T.

    2004-02-01

    Evaluating ground surface temperature (GST) is common in applied and general geothermal research. Our main focus here is investigating GST for Switzerland because of its well-known impact on low-enthalpy resources, like borehole heat exchanger (BHE) utilization. Using mainly meteorological data, we determined the present-day GST distribution through different approaches. First, we analyzed the actual GST data from the last 20 years measured at the meteorological stations of the Swiss Meteorological Institute (SMI) by investigating recent climatic history and annual variation behavior. Recent climate change seems to have a higher impact on Alpine regions than on the Alpine Foreland. Next, we determined the GST altitude dependence in the range of 200-1800 m a.s.l., using nonlinear fitting approaches and investigated the relationship between GST and surface exposure. Contrary to previous publications, no universal correlation between GST and surface exposure was found, due to local and rapid changing meteorological conditions. Finally, we used a complete data set to consider meteorologically relevant data like soil moisture, wind speed, and vegetation cover and height. The measured GST was well reproduced for the case of low vegetation, except when covered by snow and for days of subzero surface air temperature (SAT). Other locations like urban areas could not be tested. Due to the complexity of physical interaction and the resulting assessment of large data sets, this approach is not suitable for determining regional GST distribution which we need as an input for BHE modeling. A relationship between GST and SAT was defined based on the data from the meteorological stations. By applying nonlinear approaches, we established three different altitude zones that require individual consideration. By further processing, an existing SAT map was converted into the first GST map of Switzerland. To verify this new map within the range of validity (up to altitudes of 1500 m a

  5. An Open and Transparent Databank of Global Land Surface Temperature

    Science.gov (United States)

    Rennie, J.; Thorne, P.; Lawrimore, J. H.; Gleason, B.; Menne, M. J.; Williams, C.

    2013-12-01

    The International Surface Temperature Initiative (ISTI) consists of an effort to create an end-to-end process for land surface air temperature analyses. The foundation of this process is the establishment of a global land surface databank. The databank builds upon the groundbreaking efforts of scientists who led efforts to construct global land surface datasets in the 1980's and 1990's. A primary aim of the databank is to improve aspects including data provenance, version control, temporal and spatial coverage, and improved methods for bringing dozens of source data together into an integrated dataset. The databank consists of multiple stages, with each successive stage providing a higher level of processing, quality and integration. Currently more than 50 sources of data have been added to the databank. An automated algorithm has been developed that merges these sources into one complete dataset by removing duplicate station records, identifying two or more station records that can be merged into a single record, and incorporating new and unique stations. The program runs iteratively through all the sources which are ordered based upon criteria established by the ISTI. The highest preferred source, known as the target, runs through all the candidate sources, calculating station comparisons that are acceptable for merging. The process is probabilistic in approach, and the final fate of a candidate station is based upon metadata matching and data equivalence criteria. If there is not enough information, the station is withheld for further investigation. The algorithm has been validated using a pseudo-source of stations with a known time of observation bias, and correct matches have been made nearly 95% of the time. The final product, endorsed and recommended by ISTI, contains over 30,000 stations, however slight changes in the algorithm can perturb results. Subjective decisions, such as the ordering of the sources, or changing metadata and data matching thresholds

  6. Diel Surface Temperature Range Scales with Lake Size

    Science.gov (United States)

    Woolway, R. Iestyn; Jones, Ian D.; Maberly, Stephen C.; French, Jon R.; Livingstone, David M.; Monteith, Donald T.; Simpson, Gavin L.; Thackeray, Stephen J.; Andersen, Mikkel R.; Battarbee, Richard W.; DeGasperi, Curtis L.; Evans, Christopher D.; de Eyto, Elvira; Feuchtmayr, Heidrun; Hamilton, David P.; Kernan, Martin; Krokowski, Jan; Rimmer, Alon; Rose, Kevin C.; Rusak, James A.; Ryves, David B.; Scott, Daniel R.; Shilland, Ewan M.; Smyth, Robyn L.; Staehr, Peter A.; Thomas, Rhian; Waldron, Susan; Weyhenmeyer, Gesa A.

    2016-01-01

    Ecological and biogeochemical processes in lakes are strongly dependent upon water temperature. Long-term surface warming of many lakes is unequivocal, but little is known about the comparative magnitude of temperature variation at diel timescales, due to a lack of appropriately resolved data. Here we quantify the pattern and magnitude of diel temperature variability of surface waters using high-frequency data from 100 lakes. We show that the near-surface diel temperature range can be substantial in summer relative to long-term change and, for lakes smaller than 3 km2, increases sharply and predictably with decreasing lake area. Most small lakes included in this study experience average summer diel ranges in their near-surface temperatures of between 4 and 7°C. Large diel temperature fluctuations in the majority of lakes undoubtedly influence their structure, function and role in biogeochemical cycles, but the full implications remain largely unexplored. PMID:27023200

  7. Using skin temperature variability to quantify surface and subsurface estuarine processes

    Science.gov (United States)

    Brumer, S. E.; Zappa, C. J.; Anderson, S. P.; Dugan, J. P.

    2012-12-01

    IR imagery is a unique tool to study nearshore processes. It not only provides a measure for surface skin temperature, but also permits the determination of surface currents. Variations in the skin temperature arise from disruption and renewal of the thermal boundary layer (TBL) as a result of wind forcing at the air-water interface, or due to turbulent eddies generated from below. The TBL plays a critical role in nearshore processes, in particular air-water heat and gas exchanges. It is essential to characterize the spatio-temporal scales of the disruption of the TBL and the extent to which it is renewed, as well as to understand how environmental factors relate to skin temperature variability. Furthermore, it is necessary to evaluate the ability not only to derive surface currents, but also to infer subsurface properties and processes from IR images. Estuarine and inlet environments such as the Hudson River are more complex, with multitude of additional processes at play, compared to the open ocean. For instance, the atmospheric boundary layer is complicated by the fact that that air is moving over both land and water, flow is fetch limited and there is orographic steering of winds. In addition, the subsurface turbulence is enhanced due to the bottom boundary layer. Here, high resolution IR imagery was collected from a ship stationed roughly 12 miles upstream of the New York Harbor in November 2010. On a nearby piling, several in situ instruments were mounted both above and below water, measuring environmental parameters such as wind speed, heat fluxes, air and water temperature, humidity as well as subsurface currents, turbulence, temperature and salinity. An IR imager installed on the cliff overlooking the river provided a complete view of the experiment area, with both the ship and the steel piling in its field of view. This study aims not only to characterize the skin temperature variability, but also to assess the validity of the various models for surface

  8. 30 CFR 7.101 - Surface temperature tests.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Surface temperature tests. 7.101 Section 7.101... temperature tests. The test for determination of exhaust gas cooling efficiency described in § 7.102 may be... the rated horsepower specified in § 7.97(a)(2). (ii) Install sufficient temperature measuring...

  9. LAND SURFACE TEMPERATURES ESTIMATED ON GROUNDOBSERVED DATA AND SATELLITE IMAGES, DURING THE VEGETATION PERIOD IN THE OLTENIA PLAIN

    Directory of Open Access Journals (Sweden)

    ONŢEL IRINA

    2015-03-01

    Full Text Available The purpose of this study is to analyze the land surface temperatures by using climatological and remote sensing data during the vegetation period in the Oltenia Plain. The data used in this study refer both to climatological data (namely monthly and seasonal air and soil temperatures, and to remote sensing data delivered by MODIS Land Surface Temperature (LST, with a spatial resolution of 1 km. The analyzed period spans from 2000 to 2013 and the vegetation period considered is April-September. As main results, there were observed four years with high temperatures, namely 2000 (20.4oC-air T, 24.6oC soil T, and 26oC LST, 2003 (20.2oC air T, 23.9oC soil T and 24.5oC LST, 2007 (20.5oC air T, 24.3oC soil T and 25oC LST and 2012 (21.3oC air T, 25.7oC soil T and 26.5oC LST. The correlations between air temperature, soil temperature and LST were statisticaly significant. The diference between air temperature and soil temperature values ranked within 3-4oC, while the difference between soil temperature and land surface temperature obtained from MODIS images was about 0.8oC. Spatially, the highest temperatures were recorded on the Leu-Rotunda Field, the Caracal Plain and the Nedeia Field, and pretty high variations of observed temperatures seemed to depend on vegetation cover. The MODIS images represent one of the most important types of satellite data available for free, which can be successfully used in determining the climatic parameters and can help to predict the changes in plant activity, due to weather phenomena.

  10. MARSpline model for lead seven-day maximum and minimum air temperature prediction in Chennai, India

    Indian Academy of Sciences (India)

    K Ramesh; R Anitha

    2014-06-01

    In this study, a Multivariate Adaptive Regression Spline (MARS) based lead seven days minimum and maximum surface air temperature prediction system is modelled for station Chennai, India. To emphasize the effectiveness of the proposed system, comparison is made with the models created using statistical learning technique Support Vector Machine Regression (SVMr). The analysis highlights that prediction accuracy of MARS models for minimum temperature forecast are promising for short-term forecast (lead days 1 to 3) with mean absolute error (MAE) less than 1°C and the prediction efficiency and skill degrades in medium term forecast (lead days 4 to 7) with slightly above 1°C. The MAE of maximum temperature is little higher than minimum temperature forecast varying from 0.87°C for day-one to 1.27°C for lag day-seven with MARS approach. The statistical error analysis emphasizes that MARS models perform well with an average 0.2°C of reduction in MAE over SVMr models for all ahead seven days and provide significant guidance for the prediction of temperature event. The study also suggests that the correlation between the atmospheric parameters used as predictors and the temperature event decreases as the lag increases with both approaches.

  11. Multidecadal variations in the modulation of Alaska wintertime air temperature by the Madden-Julian Oscillation

    Science.gov (United States)

    Oliver, Eric C. J.

    2015-07-01

    The Madden-Julian Oscillation (MJO), the dominant mode of intraseasonal variability in the tropics, is known to influence extratropical air temperature in the Northern Hemisphere. In particular, it has been shown that intraseasonal variations in wintertime Alaska surface air temperature (SAT) is linked with variations in cross-shore surface wind and that this mechanism is driven by a train of Rossby waves originating in the tropics due to MJO forcing. We show, using long station records of Alaska SAT and an independent reconstruction of the MJO index over the twentieth century, that the MJO-SAT connection in Alaska has undergone significant multidecadal variability over the last century. The Pacific Decadal Oscillation appears to explain some of the observed multidecadal variability but fails to capture a large proportion of it. We identify four distinct periods between the years 1910 and 2000 that exhibit either a weak, moderate or strong MJO-SAT connection. The nature of our method ensures that the detected multidecadal variability is due to changes in the teleconnection mechanism and not due to changes in the strength of the MJO index. Finally, we speculate on the mechanism which may bring about such multidecadal variations in the teleconnection mechanism.

  12. Temperature Contours and Ghost-Surfaces for Chaotic Magnetic Fields

    International Nuclear Information System (INIS)

    Steady state solutions for anisotropic heat transport in a chaotic magnetic field are determined numerically and compared to a set of 'ghost-surfaces', surfaces constructed via an action-gradient flow between the minimax and minimizing periodic orbits. The ghost-surfaces are in remarkable agreement with the temperature contours.

  13. Temperature and humidity independent control (THIC) of air-conditioning system

    CERN Document Server

    Liu, Xiaohua; Zhang, Tao

    2014-01-01

    This book presents the main components of the Temperature and Humidity Independent Control (THIC) of air-conditioning systems, including dehumidification devices, high-temperature cooling devices and indoor terminal devices.

  14. Short-term effects of air temperature on plasma metabolite concentrations in patients undergoing cardiac cattheterization.

    Science.gov (United States)

    BACKGROUND: Epidemiological studies have shown associations between air temperature and cardiovascular health outcomes. Metabolic dysregulation might also play a role in the development of cardiovascular disease.OBJECTIVES: To investigate short-term temperature effects on metabol...

  15. Observational evidence of temperature trends at two levels in the surface layer

    Science.gov (United States)

    Lin, X.; Pielke, R. A., Sr.; Mahmood, R.; Fiebrich, C. A.; Aiken, R.

    2015-09-01

    Long-term surface air temperatures at 1.5 m screen level over land are used in calculating a global average surface temperature trend. This global trend is used by the IPCC and others to monitor, assess, and describe global warming or warming hiatus. Current knowledge of near-surface temperature trends with respect to height, however, is limited and inadequately understood because surface temperature observations at different heights in the surface layer in the world are rare especially from a high-quality and long-term climate monitoring network. Here we use high-quality two-height Oklahoma Mesonet observations, synchronized in time, fixed in height, and situated in relatively flat terrain, to assess temperature trends and differentiating temperature trends with respect to heights (i.e., near-surface lapse rate trend) over the period 1997 to 2013. We show that the near-surface lapse rate has significantly decreased with a trend of -0.18 ± 0.03 °C (10 m)-1 decade-1 indicating that the 9 m height temperatures increased faster than temperatures at the 1.5 m screen level and conditions at the 1.5 m height cooled faster than at the 9 m height. However, neither of the two individual height temperature trends by themselves were statistically significant. The magnitude of lapse rate trend is greatest under lighter winds at night. Nighttime lapse rate trends were significantly more negative than daytime lapse rate trends and the average lapse rate trend was three times more negative under calm conditions than under windy conditions. Our results provide the first observational evidence of near-surface temperature changes with respect to height that could enhance the assessment of climate model predictions.

  16. Integrated LTCC Pressure/Flow/Temperature Multisensor for Compressed Air Diagnostics†

    Directory of Open Access Journals (Sweden)

    Nicolas Craquelin

    2010-12-01

    Full Text Available We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues.

  17. Numerical Analysis of Exergy for Air-Conditioning Influenced by Ambient Temperature

    OpenAIRE

    Jing-Nang Lee; Chien-Chih Chen; Chen-Ching Ting

    2014-01-01

    The article presents numerical analysis of exergy for air-conditioning influenced by ambient temperature. The model of numerical simulation uses an integrated air conditioning system exposed in varied ambient temperature to observe change of the four main devices, the compressor, the condenser, the capillary, and the evaporator in correspondence to ambient temperature. The analysis devices of the four devices’s exergy influenced by the varied ambient temperature and found that the...

  18. Comparison of two methods for contactless surface temperature measurement

    Science.gov (United States)

    Piasecka, Magdalena; Michalski, Dariusz; Strąk, Kinga

    2016-03-01

    The aim of the paper is to determine the temperature filed of the heating surface on the basis of temperature measurements taken by liquid crystal thermography and infrared thermography applied in boiling heat transfer research during FC-72 flow in minichannels, and to compare them. The essential part of the experimental stand is the test section with two parallel rectangular minichannels, each 1.7 mm deep, 24 mm wide and 360 mm long. It is possible to observe the channel surfaces through panes: of the first minichannel allows observing foil temperature changes on the plain side due to liquid crystal thermography (LCT), which required treating the foil surface with thermochromic liquid crystals, of the other minichannel enables detecting outer glass or foil surface temperature changes due to infrared thermography (IRT). Comparison of the results of the measurements are presented in graphical form as thermographs and as heating surface temperature vs. minichannel length. The differences between two sets of measurement data concerning the temperature of the heating surface obtained with LCT and IRT, were analyzed using: Pearson linear correlation coefficient, determination coefficient, Experimental Method Error and Method Accuracy. The comparative data analysis shows that similar values and distributions of the surface temperature were obtained from both techniques.

  19. Comparison of two methods for contactless surface temperature measurement

    Directory of Open Access Journals (Sweden)

    Piasecka Magdalena

    2016-01-01

    Full Text Available The aim of the paper is to determine the temperature filed of the heating surface on the basis of temperature measurements taken by liquid crystal thermography and infrared thermography applied in boiling heat transfer research during FC-72 flow in minichannels, and to compare them. The essential part of the experimental stand is the test section with two parallel rectangular minichannels, each 1.7 mm deep, 24 mm wide and 360 mm long. It is possible to observe the channel surfaces through panes: of the first minichannel allows observing foil temperature changes on the plain side due to liquid crystal thermography (LCT, which required treating the foil surface with thermochromic liquid crystals, of the other minichannel enables detecting outer glass or foil surface temperature changes due to infrared thermography (IRT. Comparison of the results of the measurements are presented in graphical form as thermographs and as heating surface temperature vs. minichannel length. The differences between two sets of measurement data concerning the temperature of the heating surface obtained with LCT and IRT, were analyzed using: Pearson linear correlation coefficient, determination coefficient, Experimental Method Error and Method Accuracy. The comparative data analysis shows that similar values and distributions of the surface temperature were obtained from both techniques.

  20. Titan Surface Temperatures as Measured by Cassini CIRS

    Science.gov (United States)

    Jennings, Donald E.; Flasar, F.M.; Kunde, V.G.; Nixon, C.A.; Romani, P.N.; Samuelson, R.E.; Coustenis, A.; Courtin, R.

    2009-01-01

    Thermal radiation from the surface of Titan reaches space through a spectral window of low opacity at 19-microns wavelength. This radiance gives a measure of the brightness temperature of the surface. Composite Infrared Spectrometer' (CIRS) observations from Cassini during its first four years at Saturn have permitted latitude mapping of zonally averaged surface temperatures. The measurements are corrected for atmospheric opacity using the dependence of radiance on emission angle. With the more complete latitude coverage and much larger dataset of CIRS we have improved upon the original results from Voyager IRIS. CIRS measures the equatorial surface brightness temperature to be 93.7+/-0.6 K, the same as the temperature measured at the Huygens landing site. The surface brightness temperature decreases by 2 K toward the south pole and by 3 K toward the north pole. The drop in surface temperature between equator and north pole implies a 50% decrease in methane saturation vapor pressure and relative humidity; this may help explain the large northern lakes. The H2 mole fraction is derived as a by-product of our analysis and agrees with previous results. Evidence of seasonal variation in surface and atmospheric temperatures is emerging from CIRS measurements over the Cassini mission.

  1. Smart sensor for surface temperature measurement on manufacturing machines

    OpenAIRE

    Tansley, Dean; Fletcher, Simon; Longstaff, Andrew P.

    2013-01-01

    The requirement for accurate milling machinery gives rise to a host of controllers capable of data handling from sensors. Accurate measurement of temperature is important since thermal gradients cause deformity in machinery. The development of a temperature-measuring instrumentation system is proposed to improve surface temperature reading accuracy on machinery. The use of digital temperature sensors are combination with a 32-bit ARM cortex M4 processor enabling data handling and averaging is...

  2. Application of Curve Fitting Extrapolation in Measuring Transient Surface Temperature

    OpenAIRE

    Xiaojian Hao; Lina Hao; Hanchang Zhou; Sanping Jiang; Yanfeng Li

    2013-01-01

    The engine inner wall surface temperature was measured by the plug blind-hole extrapolation, and multiple thermocouples were installed at different depths in the substrate. The engine wall extrapolation model of transient high temperature was established according to the basic principles of heat transfer. The transient temperatures were measured by thermocouples buried at different depths of the engine wall and fitting curve was got. The transient temperature field which was generated by the ...

  3. A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009

    Science.gov (United States)

    Sharma, Sapna; Gray, Derek; Read, Jordan S.; O'Reilly, Catherine; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie; Hook, Simon; Lenters, John; Livingstone, David M.; McIntyre, Peter B.; Adrian, Rita; Allan, Mathew; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John E.; Baron, Jill S.; Brookes, Justin D; Chen, Yuwei; Daly, Robert; Ewing, Kye; de Eyto, Elvira; Dokulil, Martin; Hamilton, David B.; Havens, Karl; Haydon, Shane; Hetzenaeur, Harald; Heneberry, Jocelyn; Hetherington, Amy; Higgins, Scott; Hixson, Eric; Izmest'eva, Lyubov; Jones, Benjamin M.; Kangur, Kulli; Kasprzak, Peter; Kraemer, Benjamin; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Dörthe Müller-Navarra; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Pius Niederhauser; North, Ryan P.; Andrew Paterson; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Lars Rudstam; Rusak, James A.; Salmaso, Nico; Samal, Nihar R.; Daniel E. Schindler; Geoffrey Schladow; Schmidt, Silke R.; Tracey Schultz; Silow, Eugene A.; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A.; Craig E. Williamson; Kara H. Woo

    2015-01-01

    Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.

  4. Quantifying Surface Energy Flux Estimation Uncertainty Using Land Surface Temperature Observations

    Science.gov (United States)

    French, A. N.; Hunsaker, D.; Thorp, K.; Bronson, K. F.

    2015-12-01

    Remote sensing with thermal infrared is widely recognized as good way to estimate surface heat fluxes, map crop water use, and detect water-stressed vegetation. When combined with net radiation and soil heat flux data, observations of sensible heat fluxes derived from surface temperatures (LST) are indicative of instantaneous evapotranspiration (ET). There are, however, substantial reasons LST data may not provide the best way to estimate of ET. For example, it is well known that observations and models of LST, air temperature, or estimates of transport resistances may be so inaccurate that physically based model nevertheless yield non-meaningful results. Furthermore, using visible and near infrared remote sensing observations collected at the same time as LST often yield physically plausible results because they are constrained by less dynamic surface conditions such as green fractional cover. Although sensitivity studies exist that help identify likely sources of error and uncertainty, ET studies typically do not provide a way to assess the relative importance of modeling ET with and without LST inputs. To better quantify model benefits and degradations due to LST observational inaccuracies, a Bayesian uncertainty study was undertaken using data collected in remote sensing experiments at Maricopa, Arizona. Visible, near infrared and thermal infrared data were obtained from an airborne platform. The prior probability distribution of ET estimates were modeled using fractional cover, local weather data and a Penman-Monteith mode, while the likelihood of LST data was modeled from a two-source energy balance model. Thus the posterior probabilities of ET represented the value added by using LST data. Results from an ET study over cotton grown in 2014 and 2015 showed significantly reduced ET confidence intervals when LST data were incorporated.

  5. Time lag between the tropopause height and the levels of 7Be concentration in near surface air

    Directory of Open Access Journals (Sweden)

    Melas D.

    2012-04-01

    Full Text Available The concentration of 7Be at near surface air has been determined over 2009, a year of a deep solar minimum, in the region of Thessaloniki, Greece at 40°62′ N, 22°95'E. In geomagnetic latitudes over 40° N, the elevation of the tropopause during the warm summer months and the vertical exchange of air masses within the troposphere cause greater mixture of the air masses resulting in higher concentration levels for 7Be in surface air. The positive correlation between the monthly activity concentration of 7Be and the tropopause height (0.94, p < 0.0001, and also between 7Be concentration and the temperature T (°C (R = 0.97, p < 0.001, confirm that the increased rate of vertical transport within the troposphere, especially during warmer summer months, has as a result the descent to surface of air masses enriched in 7Be. However, the 7Be concentration levels in near surface air are not expected to respond immediately to the change of elevation of the tropopause. It was found that there's a time lag of ~ 3 days between the change in the daily surface concentrations of 7Be the change in the elevation of the tropopause.

  6. Investigation of surface properties of high temperature nitrided titanium alloys

    OpenAIRE

    Koyuncu, E.; F. Kahraman; Ö. Karadeniz

    2009-01-01

    Purpose: The purpose of paper is to investigate surface properties of high temperature nitrided titanium alloys.Design/methodology/approach: In this study, surface modification of Ti6Al4V titanium alloy was made at various temperatures by plasma nitriding process. Plasma nitriding treatment was performed in 80% N2-20% H2 gas mixture, for treatment times of 2-15 h at the temperatures of 700-1000°C. Surface properties of plasma nitrided Ti6Al4V alloy were examined by metallographic inspection, ...

  7. Linking Surface Urban Heat Islands with Groundwater Temperatures.

    Science.gov (United States)

    Benz, Susanne A; Bayer, Peter; Goettsche, Frank M; Olesen, Folke S; Blum, Philipp

    2016-01-01

    Urban temperatures are typically, but not necessarily, elevated compared to their rural surroundings. This phenomenon of urban heat islands (UHI) exists both above and below the ground. These zones are coupled through conductive heat transport. However, the precise process is not sufficiently understood. Using satellite-derived land surface temperature and interpolated groundwater temperature measurements, we compare the spatial properties of both kinds of heat islands in four German cities and find correlations of up to 80%. The best correlation is found in older, mature cities such as Cologne and Berlin. However, in 95% of the analyzed areas, groundwater temperatures are higher than land surface temperatures due to additional subsurface heat sources such as buildings and their basements. Local groundwater hot spots under city centers and under industrial areas are not revealed by satellite-derived land surface temperatures. Hence, we propose an estimation method that relates groundwater temperatures to mean annual land-surface temperatures, building density, and elevated basement temperatures. Using this method, we are able to accurately estimate regional groundwater temperatures with a mean absolute error of 0.9 K. PMID:26595444

  8. Effects of Outside Air Temperature on Movement of Phosphine Gas in Concrete Elevator Bins

    Science.gov (United States)

    Studies that measured the movement and concentration of phosphine gas in upright concrete bins over time indicated that fumigant movement was dictated by air currents, which in turn, were a function of the difference between the average grain temperature and the average outside air temperature durin...

  9. Human Response to Ductless Personalised Ventilation: Impact of Air Movement, Temperature and Cleanness on Eye Symptoms

    DEFF Research Database (Denmark)

    Dalewski, Mariusz; Fillon, Maelys; Bivolarova, Maria;

    2013-01-01

    environment facially applied individually controlled air movement of room air, with or without local filtering, did not have significant impact on eye blink frequency and tear film quality. The local air movement and air cleaning resulted in increased eye blinking frequency and improvement of tear film......The performance of ductless personalized ventilation (DPV) in conjunction with displacement ventilation (DV) was studied in relation to peoples’ health, comfort and performance. This paper presents results on the impact of room air temperature, using of DPV and local air filtration on eye blink...

  10. Diel Surface Temperature Range Scales with Lake Size

    DEFF Research Database (Denmark)

    Woolway, R Iestyn; Jones, Ian D; Maberly, Stephen C; French, Jon R; Livingstone, David M; Monteith, Donald T; Simpson, Gavin L; Thackeray, Stephen J; Andersen, Mikkel R; Battarbee, Richard W; DeGasperi, Curtis L; Evans, Christopher D; de Eyto, Elvira; Feuchtmayr, Heidrun; Hamilton, David P; Kernan, Martin; Krokowski, Jan; Rimmer, Alon; Rose, Kevin C; Rusak, James A; Ryves, David B; Scott, Daniel R; Shilland, Ewan M; Smyth, Robyn L; Staehr, Peter A; Thomas, Rhian; Waldron, Susan; Weyhenmeyer, Gesa A

    2016-01-01

    Ecological and biogeochemical processes in lakes are strongly dependent upon water temperature. Long-term surface warming of many lakes is unequivocal, but little is known about the comparative magnitude of temperature variation at diel timescales, due to a lack of appropriately resolved data. Here...... predictably with decreasing lake area. Most small lakes included in this study experience average summer diel ranges in their near-surface temperatures of between 4 and 7°C. Large diel temperature fluctuations in the majority of lakes undoubtedly influence their structure, function and role in biogeochemical...... cycles, but the full implications remain largely unexplored....

  11. MAIC-2, a latitudinal model for the Martian surface temperature, atmospheric water transport and surface glaciation

    OpenAIRE

    Greve, Ralf; Grieger, Bjoern; Stenzel, Oliver J.

    2009-01-01

    The Mars Atmosphere-Ice Coupler MAIC-2 is a simple, latitudinal model, which consists of a set of parameterisations for the surface temperature, the atmospheric water transport and the surface mass balance (condensation minus evaporation) of water ice. It is driven directly by the orbital parameters obliquity, eccentricity and solar longitude (Ls) of perihelion. Surface temperature is described by the Local Insolation Temperature (LIT) scheme, which uses a daily and latitude-dependent radiati...

  12. Measuring air layer volumes retained by submerged floating-ferns Salvinia and biomimetic superhydrophobic surfaces

    Directory of Open Access Journals (Sweden)

    Matthias J. Mayser

    2014-06-01

    Full Text Available Some plants and animals feature superhydrophobic surfaces capable of retaining a layer of air when submerged under water. Long-term air retaining surfaces (Salvinia-effect are of high interest for biomimetic applications like drag reduction in ship coatings of up to 30%. Here we present a novel method for measuring air volumes and air loss under water. We recorded the buoyancy force of the air layer on leaf surfaces of four different Salvinia species and on one biomimetic surface using a highly sensitive custom made strain gauge force transducer setup. The volume of air held by a surface was quantified by comparing the buoyancy force of the specimen with and then without an air layer. Air volumes retained by the Salvinia-surfaces ranged between 0.15 and 1 L/m2 depending on differences in surface architecture. We verified the precision of the method by comparing the measured air volumes with theoretical volume calculations and could find a good agreement between both values. In this context we present techniques to calculate air volumes on surfaces with complex microstructures. The introduced method also allows to measure decrease or increase of air layers with high accuracy in real-time to understand dynamic processes.

  13. Use of Quality Controlled AIRS Temperature Soundings to Improve Forecast Skill

    Science.gov (United States)

    Susskind, Joel; Reale, Oreste; Iredell, Lena

    2010-01-01

    AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. Also included are the clear column radiances used to derive these products which are representative of the radiances AIRS would have seen if there were no clouds in the field of view. All products also have error estimates. The sounding goals of AIRS are to produce 1 km tropospheric layer mean temperatures with an rms error of 1K, and layer precipitable water with an rms error of 20 percent, in cases with up to 90 percent effective cloud cover. The products are designed for data assimilation purposes for the improvement of numerical weather prediction, as well as for the study of climate and meteorological processes. With regard to data assimilation, one can use either the products themselves or the clear column radiances from which the products were derived. The AIRS Version 5 retrieval algorithm is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates for retrieved quantities and clear column radiances, and the use of these error estimates for Quality Control. The temperature profile error estimates are used to determine a case-by-case characteristic pressure pbest, down to which the profile is considered acceptable for data assimilation purposes. The characteristic pressure p(sub best) is determined by comparing the case dependent error estimate (delta)T(p) to the threshold values (Delta)T(p). The AIRS Version 5 data set provides error estimates of T(p) at all levels, and also profile dependent values of pbest based

  14. Effect of soil temperature on growth of cucumber in different air temperature and radiation regime-poster

    International Nuclear Information System (INIS)

    In model experiments (s. Krug and Liebig, 1979a + b, 1984) using temperature controlled beds (figure 1) in greenhouses with different set points for the heating unit of the air, the effect of soil temperature, air temperature, irradiance and ontogenetic growth and their interactions on wilting, vegetative growth, and yielding of cucumber plants (c.v. 'Pepinex 69') were investigated. Ontogenesis was regarded by the growth phases. 1.: one week after planting, 2.: one week after planting to anthesis at the 8th node, 3.: following growth. Wilting was valued by grades from 0 (fully turgescent) to 4 (strong) wilting. Soil temperatures causing wilting ≥ 1 were 16° C during the 1. phase, close below 16° C during the 2. and 3. phase in spring and autumn and close below 14° C during the 2. phase and at 12° C during the 3. phase in summer (figure 2). There was no significant effect of air temperature caused by heating. Sensibility increased with short term high irradiance in winter, but decreased with long term high irradiance (and higher temperatures) in summer. Moreover sensibility decreased with ontogenesis. Length growth of the stems was significantly promoted by higher soil temperature (up to 23° C) only during the 1. phase (figure 3). Leaf growth was promoted by higher soil temperature during the 1. and 2. phase, especially in combination with high irradiance and high air temperature (figure 4). In the 3. phase there was no significant reaction to soil temperature. Low soil temperature causing wilting during the 1. phase showed a long term retartation of stem and leaf growth (table 1). Start of harvest (1 kg fruits) was earlier with higher air temperature (checked up to 23° C) and delayed by low soil temperature which caused wilting during the 1. phase (figure 5). Yield of stem fruits was increased by soil temperature increasing from 16 to 18° C, especially of those cucumbers planted in winter (figure 6). Market quality was not significantly effected by soil

  15. On the Potential Impact of Daytime Surface Sensible Heat Flux on the Dissipation of Martian Cold Air Outbreaks

    Science.gov (United States)

    Segal, M.; Arritt, R. W.; Tillman, J. E.

    1997-01-01

    The Martian daytime soil surface temperature is governed primarily by the net irradiance balance and surface soil heat flux. Thus the outbreak of a cold air mass generates increased sensible heat flux that is conducive to daytime dissipation of the cold air mass thermal characteristics. Conceptual and scaling evaluations of this dissipation are provided while comparison is made with similar situations on Earth. It is estimated that sensible heat flux contribution to the dissipation of the original thermal structure of the cold air could be three times larger than the corresponding situation on Earth. Illustrative numerical model simulations provide scaling of the potential impact on the dissipation of cold air masses for various combinations of background wind speed and latitudes.

  16. High-temperature morphology of stepped gold surfaces

    International Nuclear Information System (INIS)

    Molecular dynamics simulations with a classical many-body potential are used to study the high-temperature stability of stepped non-melting metal surfaces. We have studied in particular the Au(111) vicinal surfaces in the (M+1, M-1, M) family and the Au(100) vicinals in the (M, 1, 1) family. Some vicinal orientations close to the non-melting Au(111) surface become unstable close to the bulk melting temperature and facet into a mixture of crystalline (111) regions and localized surface-melted regions. On the contrary, we do not find high-temperature faceting for vicinals close to Au(100), also a non-melting surface. These (100) vicinal surfaces gradually disorder with disappearance of individual steps well below the bulk melting temperature. We have also studied the high-temperature stability of ledges formed by pairs of monoatomic steps of opposite sign on the Au(111) surface. It is found that these ledges attract each other, so that several of them merge into one larger ledge, whose edge steps then act as a nucleation site for surface melting. (author). 43 refs, 8 figs

  17. COBE-SST2 Sea Surface Temperature and Ice

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A new sea surface temperature (SST) analysis on a centennial time scale is presented. The dataset starts in 1850 with monthly 1x1 means and is periodically updated....

  18. Seasonal Sea Surface Temperature Averages, 1985-2001 - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of four images showing seasonal sea surface temperature (SST) averages for the entire earth. Data for the years 1985-2001 are averaged to...

  19. Global 1-km Sea Surface Temperature (G1SST)

    Data.gov (United States)

    National Aeronautics and Space Administration — JPL OurOcean Portal: A daily, global Sea Surface Temperature (SST) data set is produced at 1-km (also known as ultra-high resolution) by the JPL ROMS (Regional...

  20. Surface passivation of nickel-chromium alloys at room temperature

    International Nuclear Information System (INIS)

    The surface composition and room temperature oxidation of atomically clean single crystal Ni-15%Cr(110) and polycrystalline Ni-23%Cr alloy have been studied using Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), Ion Scattering Spectroscopy (ISS) and Electron Stimulated Ion Desorption (ESID). It was found that Ni segregated preferentially to the surface of Ni-15%Cr(110) in vacuum at temperatures between 500 to 650 degree C, and the heat segregation was 2550 cal/mole. The surface region of the Ni-Cr alloy was depleted in Ni during Ar ion bombardment at temperatures above 200 degree C, which is an agreement with the model of preferential sputtering of Ni caused by radiation-enhanced surface segregation of Ni. But the subsurface region of room temperature sputtered Ni-Cr alloy was depleted in Cr. Possible causes for this observation were discussed

  1. OW NOAA Pathfinder/GAC Sea-Surface Temperature

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset contains satellite-derived sea-surface temperature measurements collected by means of the Advanced Very High Resolution Radiometer - Global Area...

  2. 1994 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  3. 2002 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  4. 2000 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  5. 1995 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  6. 2001 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  7. 1999 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  8. 1998 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  9. 1996 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  10. 2003 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  11. 1997 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/ NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  12. 1993 Average Monthly Sea Surface Temperature for California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA/NASA AVHRR Oceans Pathfinder sea surface temperature data are derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the...

  13. Surface Tension Gradients Induced by Temperature: The Thermal Marangoni Effect

    Science.gov (United States)

    Gugliotti, Marcos; Baptisto, Mauricio S.; Politi, Mario J.

    2004-01-01

    Surface tensions gradients were generated in a thin liquid film because of the local increase in temperature, for demonstration purposes. This is performed using a simple experiment and allows different alternatives for heat generation to be used.

  14. Tropical sea surface temperatures and the earth's orbital eccentricity cycles

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, S.M.; Fernandes, A.A.; Mohan, R.

    The tropical oceanic warm pools are climatologically important regions because their sea surface temperatures (SSTs) are positively related to atmospheric greenhouse effect and the cumulonimbus-cirrus cloud anvil. Such a warm pool is also present...

  15. NOAA High-Resolution Sea Surface Temperature (SST) Analysis Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archive covers two high resolution sea surface temperature (SST) analysis products developed using an optimum interpolation (OI) technique. The analyses have a...

  16. Temperature-Responsive Polymer Modified Surface for Cell Sheet Engineering

    Directory of Open Access Journals (Sweden)

    Teruo Okano

    2012-08-01

    Full Text Available In the past two decades, as a novel approach for tissue engineering, cell sheet engineering has been proposed by our laboratory. Poly(N-isopropylacrylamide (PIPAAm, which is a well-known temperature-responsive polymer, has been grafted on tissue culture polystyrene (TCPS surfaces through an electron beam irradiated polymerization. At 37 °C, where the PIPAAm modified surface is hydrophobic, cells can adhere, spread on the surface and grow to confluence. By decreasing temperature to 20 °C, since the surface turns to hydrophilic, cells can detach themselves from the surface spontaneously and form an intact cell sheet with extracellular matrix. For obtaining a temperature-induced cell attachment and detachment, it is necessary to immobilize an ultra thin PIPAAm layer on the TCPS surfaces. This review focuses on the characteristics of PIAPAm modified surfaces exhibiting these intelligent properties. In addition, PIPAAm modified surfaces giving a rapid cell-sheet recovery has been further developed on the basis of the characteristic of the PIPAAm surface. The designs of temperature-responsive polymer layer have provided an enormous potential to fabricate clinically applicable regenerative medicine.

  17. Skin sites to predict deep-body temperature while wearing firefighters' personal protective equipment during periodical changes in air temperature.

    Science.gov (United States)

    Kim, Siyeon; Lee, Joo-Young

    2016-04-01

    The aim of this study was to investigate stable and valid measurement sites of skin temperatures as a non-invasive variable to predict deep-body temperature while wearing firefighters' personal protective equipment (PPE) during air temperature changes. Eight male firefighters participated in an experiment which consisted of 60-min exercise and 10-min recovery while wearing PPE without self-contained breathing apparatus (7.75 kg in total PPE mass). Air temperature was periodically fluctuated from 29.5 to 35.5 °C with an amplitude of 6 °C. Rectal temperature was chosen as a deep-body temperature, and 12 skin temperatures were recorded. The results showed that the forehead and chest were identified as the most valid sites to predict rectal temperature (R(2) = 0.826 and 0.824, respectively) in an environment with periodically fluctuated air temperatures. This study suggests that particular skin temperatures are valid as a non-invasive variable when predicting rectal temperature of an individual wearing PPE in changing ambient temperatures. Practitioner Summary: This study should offer assistance for developing a more reliable indirect indicating system of individual heat strain for firefighters in real time, which can be used practically as a precaution of firefighters' heat-related illness and utilised along with physiological monitoring. PMID:26214379

  18. On the Controlling Factor of Catalyst Temperature in C3H8-Air Mixture

    Institute of Scientific and Technical Information of China (English)

    Goro ONUMA; Mitsuaki TANABE; Kiyoshi AOKI

    2001-01-01

    Catalytic combustion of propane-air mixture was investigated. Platinum catalysts over a flat stainless steel with y alumina washcoat were employed. The employed burner has three catalysts set parallel to the mixture flow, spaced at an interval of 5, 10 and 15 mm. Both experiment and numerical simulation were made at inlet temperature of 553 K, inlet velocity of 3 to 7 rn/s and equivalence ratio of 0.3 to 0.5. In the numerical simulation, two-dimensional,steady state model was developed to calculate the temperature and species concentration in gas-phase. In this model,chemical reaction on the catalyst surface and that in the gas phase were assumed to occur in three-steps. The numerical results show good agreement with experimental results. It was found that the properties of the catalyst strongly affect the catalyst surface temperature. Especially, the thermal conductivity of catalyst has a great effect,while the emissivity of catalyst has less effect.

  19. Surface temperature transients from pulsed laser heating of UO 2

    Science.gov (United States)

    Yagnik, S. K.; Olander, D. R.

    1988-07-01

    Surface heating of UO 2 by a pulsed laser was investigated theoretically and experimentally. Targets of solid uranium dioxide in vacuum were rapidly heated to peak temperatures of 3700 K, as measured by a fast-response automatic optical pyrometer. The measured target surface temperatures were compared with a one-dimensional heat transport model that accounts for conduction and melting in the solid and ablation and radiation from the surface. Congruent vaporization of UO 2 was assumed. The measured temporal and spatial characteristics of the laser beam as well as temperature-dependent physical and thermodynamic properties of UO 2 are used as input to the calculations. Agreement of the theory with the measurements was further validated by post-irradiation microscopic examination of the target surface. Additional tests were performed to assess qualitatively the attenuation of laser light and thermal radiation from the surface by the vapor blow-off from the target. This effect was found to be insignificant.

  20. Surface, Water, and Air Biocharacterization (SWAB) Flight Experiment

    Science.gov (United States)

    Castro, V. A.; Ott, C. M.; Pierson, D. L.

    2012-01-01

    The determination of risk from infectious disease during spaceflight missions is composed of several factors including both the concentration and characteristics of the microorganisms to which the crew are exposed. Thus, having a good understanding of the microbial ecology aboard spacecraft provides the necessary information to mitigate health risks to the crew. While preventive measures are taken to minimize the presence of pathogens on spacecraft, medically significant organisms have been isolated from both the Mir and International Space Station (ISS). Historically, the method for isolation and identification of microorganisms from spacecraft environmental samples depended upon their growth on culture media. Unfortunately, only a fraction of the organisms may grow on a specific culture medium, potentially omitting those microorganisms whose nutritional and physical requirements for growth are not met. To address this bias in our understanding of the ISS environment, the Surface, Water, and Air Biocharacterization (SWAB) Flight Experiment was designed to investigate and develop monitoring technology to provide better microbial characterization. For the SWAB flight experiment, we hypothesized that environmental analysis using non-culture-based technologies would reveal microorganisms, allergens, and microbial toxins not previously reported in spacecraft, allowing for a more complete health assessment. Key findings during this experiment included: a) Generally, advanced molecular techniques were able to reveal a few organisms not recovered using culture-based methods; however, there is no indication that current monitoring is "missing" any medically significant bacteria or fungi. b) Molecular techniques have tremendous potential for microbial monitoring, however, sample preparation and data analysis present challenges for spaceflight hardware. c) Analytical results indicate that some molecular techniques, such as denaturing gradient gel electrophoresis (DGGE), can

  1. Temperature dependence of surface enhanced Raman scattering on C70

    Institute of Scientific and Technical Information of China (English)

    GAO Ying; Zhang Zhenlong; DU Yinxiao; DONG Hua; MO Yujun

    2005-01-01

    The temperature dependence of surface enhanced Raman scattering of the C70 molecule is reported.The Raman scattering of C70 molecules adsorbed on the surface of a silver mirror was measured at different temperatures. The experimental results indicate that the relative intensities of the Raman features vary with the temperature of the sample. When the temperature decreases from room temperature to 0℃, the relative intensities of certain Raman bands decrease abruptly. If we take the strongest band 1565cm-1 as a standard value 100, the greatest decrease approaches to 43%. However, with the further decrease in the temperature these relative intensities increase and resume the value at room temperature. And such a temperature dependence is reversible. Our results show that the adsorption state of the C70 molecules on the silver surface around 0℃changes greatly with the temperature, resulting in a decrease in relative intensities for some main Raman features of C70molecule. When the temperature is lower than 0℃, the adsorption state changes continually and more slowly. Synchronously, eight new Raman featu res, which have not ever been reported in literature, are observed in our experiment and this enriches the basic information of the vibrational modes for C70 molecule.

  2. Surface Temperatures on Titan during Northern Winter and Spring

    Science.gov (United States)

    Jennings, D. E.; Cottini, V.; Nixon, C. A.; Achterberg, R. K.; Flasar, F. M.; Kunde, V. G.; Romani, P. N.; Samuelson, R. E.; Mamoutkine, A.; Gorius, N. J. P.; Coustenis, A.; Tokano, T.

    2016-01-01

    Meridional brightness temperatures were measured on the surface of Titan during the 2004-2014 portion of the Cassini mission by the Composite Infrared Spectrometer. Temperatures mapped from pole to pole during five two-year periods show a marked seasonal dependence. The surface temperature near the south pole over this time decreased by 2 K from 91.7 ± 0.3 to 89.7 ± 0.5 K while at the north pole the temperature increased by 1 K from 90.7 ± 0.5 to 91.5 ± 0.2 K. The latitude of maximum temperature moved from 19 S to 16 N, tracking the sub-solar latitude. As the latitude changed, the maximum temperature remained constant at 93.65 ± 0.15 K. In 2010 our temperatures repeated the north-south symmetry seen by Voyager one Titan year earlier in 1980. Early in the mission, temperatures at all latitudes had agreed with GCM predictions, but by 2014 temperatures in the north were lower than modeled by 1 K. The temperature rise in the north may be delayed by cooling of sea surfaces and moist ground brought on by seasonal methane precipitation and evaporation.

  3. The impact of temperature and humidity on perception and emission of indoor air pollutants

    DEFF Research Database (Denmark)

    Fang, Lei; Clausen, Geo; Fanger, Povl Ole

    1996-01-01

    Sensory response to air polluted by five building materials under different combinations of temperature and humidity in the ranges 18°C-28°C and 30%-70% was studied in the laboratory. The experiments were designed to study separately the impact of temperature and humidity on the perception of air...... polluted by materials, and on the emission of pollutants from the materials. At all tested pollution levels of the five materials, the air was perceived significantly less acceptable with increasing temperature and humidity, and the impact of temperature and humidity on perception decreased with increasing...... pollution level. A significant linear correlation between acceptability and enthalpy of the air was found to describe the influence of temperature and humidity on perception. The impact of temperature and humidity on sensory emission was less significant than the impact on perception; however, the sensory...

  4. Equilibrium panel surface temperatures in the SNAP-2 instrument compartment

    Energy Technology Data Exchange (ETDEWEB)

    Gresho, P.M.

    1962-09-14

    By equating net radiation to space to I/sup 2/R heating in the SNAP-2 instrument compartments, and neglecting internal radiation between compartments, the panel surface equilibrium temperatures were computed for hot and cold temperature extremes. These extremes are defined by: (1) cold - pre-start phase in the shade, (2) hot - full power phase facing the sun. The results of the heat balances for hottest and coldest cases are presented graphically. These figures relate the equilibrium surface temperatures to the I/sup 2/R heat load dissipated by the panel surface for hot and cold orbits before and after startup. Included as parameters are effective panel area (dependent on Agena-interface design details) and the ..cap alpha../epsilon ratio for the surface coating. If ..cap alpha../epsilon = .3/.9 and A = 1 ft/sup 2/, the extremes of temperatures suffered are from -191/sup 0/F to +212/sup 0/F. This study shows that the normal R/C surface coating (..cap alpha../epsilon = .3/.9) is acceptable regarding allowable maximum surface temperatures, if the effective panel area is not less than 1 ft/sup 2/. It also indicates that further work is warranted regarding internal radiative distribution of heat in order to limit the lowest temperatures to -65/sup 0/F.

  5. Numerical Analysis of Exergy for Air-Conditioning Influenced by Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Jing-Nang Lee

    2014-07-01

    Full Text Available The article presents numerical analysis of exergy for air-conditioning influenced by ambient temperature. The model of numerical simulation uses an integrated air conditioning system exposed in varied ambient temperature to observe change of the four main devices, the compressor, the condenser, the capillary, and the evaporator in correspondence to ambient temperature. The analysis devices of the four devices’s exergy influenced by the varied ambient temperature and found that the capillary has unusual increasing exergy loss vs. increasing ambient temperature in comparison to the other devices. The result shows that reducing exergy loss of the capillary influenced by the ambient temperature is the key for improving working efficiency of an air-conditioning system when influence of the ambient temperature is considered. The higher ambient temperature causes the larger pressure drop of capillary and more exergy loss.

  6. 基于MODIS地表参数产品和地理数据的近地层气温估算方法评价——以安徽省为例%The Evaluation of MODIS Data and Geographic Data for Estimating Near Surface Air Temperature

    Institute of Scientific and Technical Information of China (English)

    曲培青; 施润和; 刘朝顺; 钟洪麟

    2011-01-01

    为研究应用MODIS地表参数产品估算近地层气温的可行性,对MODIS地表温度(LST)、反照率(ALBEDO)、植被指数(NDVI)等产品数据和高程(ALT)、纬度(LAT)等地理数据进行主成分分析,并以主成分累积方差较大的前若干个主成分作为自变量,建立自变量与各气象台站气温之间的多元线性关系.结果显示:所建立的多元线性回归模型的均方根误差(RMSE)均在0.5 ~2.4之间,其中,与月平均最高气温(Tmax)和14时气温(T14)回归得到的RMSE整体较大,与月平均最低气温(Tmin)回归得到的RMSE整体较小;RMSE的波动呈现出冬季大、夏季小的季节特征;利用Terra/MODIS数据得到的结果优于利用Aqua/MODIS数据得到的结果,且其夜间数据对Tmin的估算精度较高,日间数据对Tmax和T14的估算精度较高;各参数对气温回归权值影响从大到小依次为LST、ALT、LAT、NDVI和ALBEDO.因此,利用MODIS地表参数产品可以监测不同时刻的近地层气温空间分布,但对不同时刻的气温回归分析,最优数据选择有所不同.%The main objective of this study is to discuss the feasibility of predicting near - surface air temperature using MODIS products. Principal component analysis of land surface temperature (LST), ALBEDO, vegetation index (NDVI) , altitude (ALT) and latitude ( LAT) was employed, with some principal components of the cumulative variance in the front of these principal components as independent variables. Multiple linear relationships between independent variables and meteorological observation temperatures were established. The results show that the range of RMSE is between 0.5 and 2.3. Most of RMSE vary greatly in winter months but are relatively stable in summer months. Compared with Aqua/MODIS, Terra/MODIS can get better results. RMSE of Tmin modeled by Terra nighttime MODIS is lower, and so are Tmax and T14 modeled by Terra daytime MODIS. LST is the most powerful predictor, followed by ALT

  7. Correlation of noninvasive surface temperature measurement with rectal temperature in swine.

    Science.gov (United States)

    Zinn, K R; Zinn, G M; Jesse, G W; Mayes, H F; Ellersieck, M R

    1985-06-01

    Skin and rectal temperature measurements were taken on 15 crossbred sows and gilts (225 kg) during the last 5 days of prepartum period and compared with those recorded in the first 8 days after parturition. The correlation of skin and rectal temperature values was not good during either period, although an increased correlation was noted in the postparturient period. The rectal temperature significantly (P less than 0.05) increased in the postparturient period, but the mean surface temperature was unchanged. This would indicate a decreased blood flow to the surface, since an equivalent blood flow to the surface after a rectal temperature increase would result in a concomitant mean surface temperature increase. The decreased flow to the surface of the animal was selective, since a significant (P less than 0.05) decrease in surface temperature was noted at the tailhead, perineum, vulva, mammae-caudal, and eye, whereas the surface temperature of the mammae-cranial and mammae-middle was significantly (P less than 0.05) increased. PMID:4026016

  8. Effect of pyrolysis temperature and air flow on toxicity of gases from a polycarbonate polymer

    Science.gov (United States)

    Hilado, C. J.; Brick, V. E.; Brauer, D. P.

    1978-01-01

    A polycarbonate polymer was evaluated for toxicity of pyrolysis gases generated at various temperatures without forced air flow and with 1 L/min air flow, using the toxicity screening test method developed at the University of San Francisco. Time to various animal responses decreased with increasing pyrolysis temperature over the range from 500 C to 800 C. There appeared to be no significant toxic effects at 400 C and lower temperatures.

  9. Turbulent Transfer Coefficients and Calculation of Air Temperature inside Tall Grass Canopies in Land Atmosphere Schemes for Environmental Modeling.

    Science.gov (United States)

    Mihailovic, D. T.; Alapaty, K.; Lalic, B.; Arsenic, I.; Rajkovic, B.; Malinovic, S.

    2004-10-01

    A method for estimating profiles of turbulent transfer coefficients inside a vegetation canopy and their use in calculating the air temperature inside tall grass canopies in land surface schemes for environmental modeling is presented. The proposed method, based on K theory, is assessed using data measured in a maize canopy. The air temperature inside the canopy is determined diagnostically by a method based on detailed consideration of 1) calculations of turbulent fluxes, 2) the shape of the wind and turbulent transfer coefficient profiles, and 3) calculation of the aerodynamic resistances inside tall grass canopies. An expression for calculating the turbulent transfer coefficient inside sparse tall grass canopies is also suggested, including modification of the corresponding equation for the wind profile inside the canopy. The proposed calculations of K-theory parameters are tested using the Land Air Parameterization Scheme (LAPS). Model outputs of air temperature inside the canopy for 8 17 July 2002 are compared with micrometeorological measurements inside a sunflower field at the Rimski Sancevi experimental site (Serbia). To demonstrate how changes in the specification of canopy density affect the simulation of air temperature inside tall grass canopies and, thus, alter the growth of PBL height, numerical experiments are performed with LAPS coupled with a one-dimensional PBL model over a sunflower field. To examine how the turbulent transfer coefficient inside tall grass canopies over a large domain represents the influence of the underlying surface on the air layer above, sensitivity tests are performed using a coupled system consisting of the NCEP Nonhydrostatic Mesoscale Model and LAPS.

  10. Recent climate warming: surface air temperature series and geothermal evidence

    Czech Academy of Sciences Publication Activity Database

    Čermák, Vladimír; Šafanda, Jan; Krešl, Milan; Dědeček, Petr; Bodri, L.

    2000-01-01

    Roč. 44, č. 3 (2000), s. 430-441. ISSN 0039-3169 R&D Projects: GA AV ČR IAA3012706; GA ČR GA205/97/0900 Institutional research plan: CEZ:AV0Z3012916 Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.761, year: 2000

  11. Köppen-Geiger Climate Classification for Europe Recaptured via the Hölder Regularity of Air Temperature Data

    Science.gov (United States)

    Deliège, Adrien; Nicolay, Samuel

    2016-08-01

    In this paper, we make use of the monoHölder nature of surface air temperature data to recapture the Köppen-Geiger climate classification in Europe. Using data from the European Climate Assessment and Dataset (ECA&D), we first show that the Hölder exponents of surface air temperature data are statistically related to pressure anomalies. Then, we establish a climate classification based on these Hölder exponents in such a way that it allows to recover the Köppen-Geiger climate classification. We show that the two classifications match for a vast majority of stations, and we corroborate these observations with a confirmation test. We compare these results with those obtained with another dataset (NCEP-NCAR Reanalysis Project) to show that the new classification is still well-adapted, before eventually discussing these findings.

  12. Köppen-Geiger Climate Classification for Europe Recaptured via the Hölder Regularity of Air Temperature Data

    Science.gov (United States)

    Deliège, Adrien; Nicolay, Samuel

    2016-07-01

    In this paper, we make use of the monoHölder nature of surface air temperature data to recapture the Köppen-Geiger climate classification in Europe. Using data from the European Climate Assessment and Dataset (ECA&D), we first show that the Hölder exponents of surface air temperature data are statistically related to pressure anomalies. Then, we establish a climate classification based on these Hölder exponents in such a way that it allows to recover the Köppen-Geiger climate classification. We show that the two classifications match for a vast majority of stations, and we corroborate these observations with a confirmation test. We compare these results with those obtained with another dataset (NCEP-NCAR Reanalysis Project) to show that the new classification is still well-adapted, before eventually discussing these findings.

  13. Research on software development of air temperature prediction in coal face

    Institute of Scientific and Technical Information of China (English)

    QIN Yue-ping; LIU Hong-bo; WANG Ke; LIU Jiang-yue

    2011-01-01

    With ever-increasing depth of coal mine and the continuous improvement of mechanization,heat damage has become one of the major disasters in coal mine exploitation.Established the temperature prediction models suitable for different kinds of tunnels through analysis of the heat of shafts,roadways and working faces.The average annual air temperature prediction equation from the inlets of shafts to the working faces was derived.The formula was deduced using combine method of iteration and direct calculation.The method can improve the precision of air temperature prediction,so we could establish the whole pathway air temperature prediction model with high precision.Emphasizing on the effects of leakage air to air temperature of working face and using the ideology of the finite difference method and considering the differential equation of inlet and outlet at different stages,this method can significantly improve the accuracy of temperature prediction.Program development uses Visual Basic 6.0 Language,and the Origin software was used to fit the relevant data.The predicted results shows that the air temperature generally tends to rapidly increase in the air inlet,then changes slowly on working face,and finally increases sharply in air outlet in the condition of goaf air leakage.The condition is in general consistent with the air temperature change tendency of working face with U-type ventilation system.The software can provide reliable scientific basis for reasonable ventilation,cooling measures and management of coal mine thermal hazards.

  14. An observation-based assessment of the influences of air temperature and snow depth on soil temperature in Russia

    International Nuclear Information System (INIS)

    This study assessed trends in the variability of soil temperature (TSOIL) using spatially averaged observation records from Russian meteorological land stations. The contributions of surface air temperature (SAT) and snow depth (SND) to TSOIL variation were quantitatively evaluated. Composite time series of these data revealed positive trends during the period of 1921–2011, with accelerated increases since the 1970s. The TSOIL warming rate over the entire period was faster than the SAT warming rate in both permafrost and non-permafrost regions, suggesting that SND contributes to TSOIL warming. Statistical analysis revealed that the highest correlation between SND and TSOIL was in eastern Siberia, which is underlain by permafrost. SND in this region accounted for 50% or more of the observed variation in TSOIL. TSOIL in the non-permafrost region of western Siberia was significantly correlated with changes in SAT. Thus, the main factors associated with TSOIL variation differed between permafrost and non-permafrost regions. This finding underscores the importance of including SND data when assessing historical and future variations and trends of permafrost in the Northern Hemisphere. (letter)

  15. Surface temperature measurement of plasma facing components in tokamaks

    International Nuclear Information System (INIS)

    During this PhD, the challenges on the non-intrusive surface temperature measurements of metallic plasma facing components in tokamaks are reported. Indeed, a precise material emissivity value is needed for classical infrared methods and the environment contribution has to be known particularly for low emissivities materials. Although methods have been developed to overcome these issues, they have been implemented solely for dedicated experiments. In any case, none of these methods are suitable for surface temperature measurement in tokamaks.The active pyrometry introduced in this study allows surface temperature measurements independently of reflected flux and emissivities using pulsed and modulated photothermal effect. This method has been validated in laboratory on metallic materials with reflected fluxes for pulsed and modulated modes. This experimental validation is coupled with a surface temperature variation induced by photothermal effect and temporal signal evolvement modelling in order to optimize both the heating source characteristics and the data acquisition and treatment. The experimental results have been used to determine the application range in temperature and detection wavelengths. In this context, the design of an active pyrometry system on tokamak has been completed, based on a bicolor camera for a thermography application in metallic (or low emissivity) environment.The active pyrometry method introduced in this study is a complementary technique of classical infrared methods used for thermography in tokamak environment which allows performing local and 2D surface temperature measurements independently of reflected fluxes and emissivities. (author)

  16. Surface plasmon enhanced photoluminescence from copper nanoparticles: Influence of temperature

    International Nuclear Information System (INIS)

    Anomalous temperature dependence of surface plasmon enhanced photoluminescence from copper nanoparticles embedded in a silica host matrix has been observed. The quantum yield of photoluminescence increases as the temperature increases. The key role of such an effect is the interplay between the surface plasmon resonance and the interband transitions in the copper nanoparticles occurring at change of the temperature. Namely, the increase of temperature leads to the red shift of the resonance. The shift leads to increase of the spectral overlap of the resonance with photoluminescence band of copper as well as to the decrease of plasmon damping caused by interband transitions. Such mechanisms lead to the increase of surface plasmon enhancement factor and, consequently, to increase of the quantum yield of the photoluminescence

  17. Mathematical model of the metal mould surface temperature optimization

    Energy Technology Data Exchange (ETDEWEB)

    Mlynek, Jaroslav, E-mail: jaroslav.mlynek@tul.cz; Knobloch, Roman, E-mail: roman.knobloch@tul.cz [Department of Mathematics, FP Technical University of Liberec, Studentska 2, 461 17 Liberec, The Czech Republic (Czech Republic); Srb, Radek, E-mail: radek.srb@tul.cz [Institute of Mechatronics and Computer Engineering Technical University of Liberec, Studentska 2, 461 17 Liberec, The Czech Republic (Czech Republic)

    2015-11-30

    The article is focused on the problem of generating a uniform temperature field on the inner surface of shell metal moulds. Such moulds are used e.g. in the automotive industry for artificial leather production. To produce artificial leather with uniform surface structure and colour shade the temperature on the inner surface of the mould has to be as homogeneous as possible. The heating of the mould is realized by infrared heaters located above the outer mould surface. The conceived mathematical model allows us to optimize the locations of infrared heaters over the mould, so that approximately uniform heat radiation intensity is generated. A version of differential evolution algorithm programmed in Matlab development environment was created by the authors for the optim