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Sample records for diurnal surface temperature

  1. A model of the diurnal variation in lake surface temperature

    NASA Astrophysics Data System (ADS)

    Hodges, Jonathan L.

    Satellite measurements of water surface temperature can benefit several environmental applications such as predictions of lake evaporation, meteorological forecasts, and predictions of lake overturning events, among others. However, limitations on the temporal resolution of satellite measurements restrict these improvements. A model of the diurnal variation in lake surface temperature could potentially increase the effective temporal resolution of satellite measurements of surface temperature, thereby enhancing the utility of these measurements in the above applications. Herein, a one-dimensional transient thermal model of a lake is used in combination with surface temperature measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua and Terra satellites, along with ambient atmospheric conditions from local weather stations, and bulk temperature measurements to calculate the diurnal surface temperature variation for the five major lakes in the Savannah River Basin in South Carolina: Lakes Jocassee, Keowee, Hartwell, Russell, and Thurmond. The calculated solutions are used to obtain a functional form for the diurnal surface temperature variation of these lakes. Differences in diurnal variation in surface temperature between each of these lakes are identified and potential explanations for these differences are presented.

  2. Diurnal Variations of Titan's Surface Temperatures From Cassini -CIRS Observations

    NASA Astrophysics Data System (ADS)

    Cottini, Valeria; Nixon, Conor; Jennings, Don; Anderson, Carrie; Samuelson, Robert; Irwin, Patrick; Flasar, F. Michael

    The Cassini Composite Infrared Spectrometer (CIRS) observations of Saturn's largest moon, Titan, are providing us with the ability to detect the surface temperature of the planet by studying its outgoing radiance through a spectral window in the thermal infrared at 19 m (530 cm-1) characterized by low opacity. Since the first acquisitions of CIRS Titan data the in-strument has gathered a large amount of spectra covering a wide range of latitudes, longitudes and local times. We retrieve the surface temperature and the atmospheric temperature pro-file by modeling proper zonally averaged spectra of nadir observations with radiative transfer computations. Our forward model uses the correlated-k approximation for spectral opacity to calculate the emitted radiance, including contributions from collision induced pairs of CH4, N2 and H2, haze, and gaseous emission lines (Irwin et al. 2008). The retrieval method uses a non-linear least-squares optimal estimation technique to iteratively adjust the model parameters to achieve a spectral fit (Rodgers 2000). We show an accurate selection of the wide amount of data available in terms of footprint diameter on the planet and observational conditions, together with the retrieved results. Our results represent formal retrievals of surface brightness temperatures from the Cassini CIRS dataset using a full radiative transfer treatment, and we compare to the earlier findings of Jennings et al. (2009). The application of our methodology over wide areas has increased the planet coverage and accuracy of our knowledge of Titan's surface brightness temperature. In particular we had the chance to look for diurnal variations in surface temperature around the equator: a trend with slowly increasing temperature toward the late afternoon reveals that diurnal temperature changes are present on Titan surface. References: Irwin, P.G.J., et al.: "The NEMESIS planetary atmosphere radiative transfer and retrieval tool" (2008). JQSRT, Vol. 109, pp

  3. Inferring land surface parameters from the diurnal variability of microwave and infrared temperatures

    NASA Astrophysics Data System (ADS)

    Norouzi, Hamidreza; Temimi, Marouane; AghaKouchak, Amir; Azarderakhsh, Marzieh; Khanbilvardi, Reza; Shields, Gerarda; Tesfagiorgis, Kibrewossen

    This study investigates the properties of the diurnal cycle of microwave brightness temperatures (TB), namely the phase and the amplitude, and their variability in time and space over the globe to infer information on key land surface parameters like changes in soil texture spatial distribution, soil moisture conditions, and vegetation density. The phase corresponds to the lag between Land Surface Temperature (LST) and TB diurnal cycles. The amplitude is determined as the difference between the maximum and the minimum of TB diurnal cycle. The diurnal cycle of TB was constructed using observations from the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) and the Special Sensor Microwave/Imager (SSM/I). The latter offer a series of sensors, namely, F13, F14, and F15 that were used in this study for a higher temporal coverage and more accurate diurnal cycle determination. LST estimates, which are available every 3 h from the International Satellite Cloud Climatology Project (ISCCP) database were used to build the LST diurnal cycle. ISCCP LST data is an infrared-based temperature with almost no penetration and is the representative of top skin temperature. The analyses of the diurnal cycles showed that the diurnal amplitude of TB decreases as the vegetation density increases, especially in the case of low frequencies which penetrate deeper into the canopy which makes them more sensitive to changes in vegetation density. The interannual variations of TB diurnal amplitudes were also in agreement with the seasonality of the vegetation cover. Over desert and rain forest regions where surface conditions do not vary significantly throughout the year, the changes in diurnal amplitudes were the lowest. A relationship between phase and amplitude values was established. It was found that the amplitude of TB diurnal cycle decreases when the phase lag increases. The spatial distribution of the determined diurnal properties, namely, phase and amplitude of TB

  4. A framework for global diurnally-resolved observations of Land Surface Temperature

    NASA Astrophysics Data System (ADS)

    Ghent, Darren; Remedios, John

    2014-05-01

    Land surface temperature (LST) is the radiative skin temperature of the land, and is one of the key parameters in the physics of land-surface processes on regional and global scales. Being a key boundary condition in land surface models, which determine the surface to atmosphere fluxes of heat, water and carbon; thus influencing cloud cover, precipitation and atmospheric chemistry predictions within Global models, the requirement for global diurnal observations of LST is well founded. Earth Observation satellites offer an opportunity to obtain global coverage of LST, with the appropriate exploitation of data from multiple instruments providing a capacity to resolve the diurnal cycle on a global scale. Here we present a framework for the production of global, diurnally resolved, data sets for LST which is a key request from users of LST data. We will show how the sampling of both geostationary and low earth orbit data sets could conceptually be employed to build combined, multi-sensor, pole-to-pole data sets. Although global averages already exist for individual instruments and merging of geostationary based LST is already being addressed operationally (Freitas, et al., 2013), there are still a number of important challenges to overcome. In this presentation, we will consider three of the issues still open in LST remote sensing: 1) the consistency amongst retrievals; 2) the clear-sky bias and its quantification; and 3) merging methods and the propagation of uncertainties. For example, the combined use of both geostationary earth orbit (GEO) and low earth orbit (LEO) data, and both infra-red and microwave data are relatively unexplored but are necessary to make the most progress. Hence this study will suggest what is state-of-the-art and how considerable advances can be made, accounting also for recent improvements in techniques and data quality. The GlobTemperature initiative under the Data User Element of ESA's 4th Earth Observation Envelope Programme (2013

  5. A framework for global diurnally-resolved observations of Land Surface Temperature

    NASA Astrophysics Data System (ADS)

    Ghent, D.; Remedios, J.; Pinnock, S.

    2013-12-01

    Land surface temperature (LST) is the radiative skin temperature of the land, and is one of the key parameters in the physics of land-surface processes on regional and global scales. Being a key boundary condition in land surface models, which determine the surface to atmosphere fluxes of heat, water and carbon; thus influencing cloud cover, precipitation and atmospheric chemistry predictions within Global models, the requirement for global diurnal observations of LST is well founded. Earth Observation satellites offer an opportunity to obtain global coverage of LST, with the appropriate exploitation of data from multiple instruments providing a capacity to resolve the diurnal cycle on a global scale. Here we present a framework for the production of global, diurnally resolved, data sets for LST which is a key request from users of LST data. We will show how the sampling of both geostationary and low earth orbit data sets could conceptually be employed to build combined, multi-sensor, pole-to-pole data sets. Although global averages already exist for individual instruments and merging of geostationary based LST is already being addressed operationally (Freitas, et al., 2013), there are still a number of important challenges to overcome. In this presentation, we will consider three of the issues still open in LST remote sensing: 1) the consistency amongst retrievals; 2) the clear-sky bias and its quantification; and 3) merging methods and the propagation of uncertainties. For example, the combined use of both geostationary earth orbit (GEO) and low earth orbit (LEO) data, and both infra-red and microwave data are relatively unexplored but are necessary to make the most progress. Hence this study will suggest what is state-of-the-art and how considerable advances can be made, accounting also for recent improvements in techniques and data quality. The GlobTemperature initiative under the Data User Element of ESA's 4th Earth Observation Envelope Programme (2013

  6. Reconciling Diurnal Features of Thermal- and Microwave-derived Land Surface Temperature

    NASA Astrophysics Data System (ADS)

    Holmes, T. R.; Crow, W. T.; Hain, C.; Anderson, M. C.

    2013-12-01

    Land surface temperature (T), a key ingredient for physically-based retrieval algorithms of hydrological states and fluxes, remains a poorly constrained parameter for global scale studies. The main two observational methods to remotely measure T are based on thermal infrared (TIR) observations and passive microwave observations (PMW). TIR is the most commonly used approach and the method of choice to provide standard T products for various satellite missions. It has found wide application, for example in energy balance approaches to retrieve land surface evapotranspiration. PMW-based T retrievals on the other hand are not as widely adopted for land applications; currently their principle use is in soil moisture retrieval algorithms. PMW and TIR technologies present two highly complementary and independent means of measuring T. PMW observations have a high tolerance to clouds but a low spatial resolution, and TIR has a high spatial resolution with temporal sampling restricted to clear skies. Furthermore, a combination of these T estimates with independent errors would inevitably reduce the overall uncertainty in estimating T. The need for improved T estimates at global scale for use in physical retrieval models of land surface parameters have motivated our work to understand the structural differences in the characteristics of the shape of the diurnal temperature cycle (DTC) as observed by PMW and TIR sensors. The ultimate goal of this work is to create a merged PMW and TIR temperature product that is spatially and diurnally continuous. This paper will report on recent progress in characterizing the main structural components of the DTC that explain differences in TIR and PMW estimates of T. Spatial patterns in DTC timing (phase lag with solar noon) have been calculated for TIR, PMW and compared to weather prediction estimates. Based on knowledge of DTC timing, which is relatively stable over the year, the DTC amplitude is studied in terms of spatial and temporal

  7. Retrieval and Mapping of Soil Texture Based on Land Surface Diurnal Temperature Range Data from MODIS

    PubMed Central

    Wang, De-Cai; Zhang, Gan-Lin; Zhao, Ming-Song; Pan, Xian-Zhang; Zhao, Yu-Guo; Li, De-Cheng; Macmillan, Bob

    2015-01-01

    Numerous studies have investigated the direct retrieval of soil properties, including soil texture, using remotely sensed images. However, few have considered how soil properties influence dynamic changes in remote images or how soil processes affect the characteristics of the spectrum. This study investigated a new method for mapping regional soil texture based on the hypothesis that the rate of change of land surface temperature is related to soil texture, given the assumption of similar starting soil moisture conditions. The study area was a typical flat area in the Yangtze-Huai River Plain, East China. We used the widely available land surface temperature product of MODIS as the main data source. We analyzed the relationships between the content of different particle soil size fractions at the soil surface and land surface day temperature, night temperature and diurnal temperature range (DTR) during three selected time periods. These periods occurred after rainfalls and between the previous harvest and the subsequent autumn sowing in 2004, 2007 and 2008. Then, linear regression models were developed between the land surface DTR and sand (> 0.05 mm), clay (< 0.001 mm) and physical clay (< 0.01 mm) contents. The models for each day were used to estimate soil texture. The spatial distribution of soil texture from the studied area was mapped based on the model with the minimum RMSE. A validation dataset produced error estimates for the predicted maps of sand, clay and physical clay, expressed as RMSE of 10.69%, 4.57%, and 12.99%, respectively. The absolute error of the predictions is largely influenced by variations in land cover. Additionally, the maps produced by the models illustrate the natural spatial continuity of soil texture. This study demonstrates the potential for digitally mapping regional soil texture variations in flat areas using readily available MODIS data. PMID:26090852

  8. Retrieval and Mapping of Soil Texture Based on Land Surface Diurnal Temperature Range Data from MODIS.

    PubMed

    Wang, De-Cai; Zhang, Gan-Lin; Zhao, Ming-Song; Pan, Xian-Zhang; Zhao, Yu-Guo; Li, De-Cheng; Macmillan, Bob

    2015-01-01

    Numerous studies have investigated the direct retrieval of soil properties, including soil texture, using remotely sensed images. However, few have considered how soil properties influence dynamic changes in remote images or how soil processes affect the characteristics of the spectrum. This study investigated a new method for mapping regional soil texture based on the hypothesis that the rate of change of land surface temperature is related to soil texture, given the assumption of similar starting soil moisture conditions. The study area was a typical flat area in the Yangtze-Huai River Plain, East China. We used the widely available land surface temperature product of MODIS as the main data source. We analyzed the relationships between the content of different particle soil size fractions at the soil surface and land surface day temperature, night temperature and diurnal temperature range (DTR) during three selected time periods. These periods occurred after rainfalls and between the previous harvest and the subsequent autumn sowing in 2004, 2007 and 2008. Then, linear regression models were developed between the land surface DTR and sand (> 0.05 mm), clay (< 0.001 mm) and physical clay (< 0.01 mm) contents. The models for each day were used to estimate soil texture. The spatial distribution of soil texture from the studied area was mapped based on the model with the minimum RMSE. A validation dataset produced error estimates for the predicted maps of sand, clay and physical clay, expressed as RMSE of 10.69%, 4.57%, and 12.99%, respectively. The absolute error of the predictions is largely influenced by variations in land cover. Additionally, the maps produced by the models illustrate the natural spatial continuity of soil texture. This study demonstrates the potential for digitally mapping regional soil texture variations in flat areas using readily available MODIS data. PMID:26090852

  9. Impact of the ocean diurnal variations on the intraseasonal variability of Sea Surface Temperatures in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Guemas, V.; Salas-Mélia, D.; Kageyama, M.; Giordani, H.; Voldoire, A.

    2009-09-01

    Some recent studies have shown that the ocean diurnal cycle could increase the intraseasonal variability of the Sea Surface Temperatures (SST) in the Tropics (Shinoda and Hendon, 1998; Bernie et al, 2005; Shinoda, 2005). This study aims at extending these analyses to the mid-latitudes. The non linear processes by which the ocean diurnal variations can affect the intraseasonal sea surface temperatures (SST) variability are investigated. To conduct these analyses, the CNRMOM1D 1-dimensional ocean model is forced with ERA40 reanalysis data with a 1 hour frequency in solar heat flux ( 6h hours for the other forcing fields ). The turbulent vertical mixing scheme (Gaspar et al., 1988) is based on the parameterisation of the second-order turbulent moments expressed as a function of the turbulent kinetic energy. The model has 124 vertical levels with a vertical resolution of 1m near the surface and 500m at the bottom. This high vertical resolution combined with a high temporal forcing resolution allows to simulate a realistic diurnal cycle of the oceanic upper-layers. This experiment is compared with one forced on a daily time-step. The comparison between both experiments highlights an impact of the ocean diurnal variations on the amplitude of the intraseasonal SST variability in the Tropics and on its timing in the mid-latitudes. In the mid-latitudes, diurnal variations in wind stress and non solar heat flux are shown to affect the daily mean SST. Since such a temperature anomaly associated with the ocean diurnal variations persists for 15 to 40 days in the midlatitudes, the ocean diurnal variations are shown to affect the intraseasonal SST variability.

  10. Clouds, radiation, and the diurnal cycle of sea surface temperature in the tropical Western Pacific

    SciTech Connect

    Webster, P.J.; Clayson, C.A.; Curry, J.A.

    1996-04-01

    In the tropical Western Pacific (TWP) Ocean, the clouds and the cloud-radiation feedback can only be understood in the context of air/sea interactions and the ocean mixed layer. Considerable interest has been shown in attempting to explain why sea surface temperature (SST) rarely rises above 30{degrees}C, and gradients of the SST. For the most part, observational studies that address this issue have been conducted using monthly cloud and SST data, and the focus has been on intraseasonal and interannual time scales. For the unstable tropical atmosphere, using monthly averaged data misses a key feedback between clouds and SST that occurs on the cloud-SST coupling time scale, which was estimated to be 3-6 days for the unstable tropical atmosphere. This time scale is the time needed for a change in cloud properties, due to the change of ocean surface evaporation caused by SST variation, to feed back to the SST variation, to feed back to the SST through its effect on the surface heat flux. This paper addresses the relationship between clouds, surface radiation flux and SST of the TWP ocean over the diurnal cycle.

  11. Partitioning Evapotranspiration in Semiarid Grassland and Shrubland Ecosystems Using Diurnal Surface Temperature Variation

    NASA Technical Reports Server (NTRS)

    Moran, M. Susan; Scott, Russell L.; Keefer, Timothy O.; Paige, Ginger B.; Emmerich, William E.; Cosh, Michael H.; O'Neill, Peggy E.

    2007-01-01

    The encroachment of woody plants in grasslands across the Western U.S. will affect soil water availability by altering the contributions of evaporation (E) and transpiration (T) to total evapotranspiration (ET). To study this phenomenon, a network of flux stations is in place to measure ET in grass- and shrub-dominated ecosystems throughout the Western U.S. A method is described and tested here to partition the daily measurements of ET into E and T based on diurnal surface temperature variations of the soil and standard energy balance theory. The difference between the mid-afternoon and pre-dawn soil surface temperature, termed Apparent Thermal Inertia (I(sub A)), was used to identify days when E was negligible, and thus, ET=T. For other days, a three-step procedure based on energy balance equations was used to estimate Qe contributions of daily E and T to total daily ET. The method was tested at Walnut Gulch Experimental Watershed in southeast Arizona based on Bowen ratio estimates of ET and continuous measurements of surface temperature with an infrared thermometer (IRT) from 2004- 2005, and a second dataset of Bowen ratio, IRT and stem-flow gage measurements in 2003. Results showed that reasonable estimates of daily T were obtained for a multi-year period with ease of operation and minimal cost. With known season-long daily T, E and ET, it is possible to determine the soil water availability associated with grass- and shrub-dominated sites and better understand the hydrologic impact of regional woody plant encroachment.

  12. A numerical study of diurnally varying surface temperature on flow patterns and pollutant dispersion in street canyons

    NASA Astrophysics Data System (ADS)

    Tan, Zijing; Dong, Jingliang; Xiao, Yimin; Tu, Jiyuan

    2015-03-01

    The impacts of the diurnal variation of surface temperature on street canyon flow pattern and pollutant dispersion are investigated based on a two-dimensional street canyon model under different thermal stratifications. Uneven distributed street temperature conditions and a user-defined wall function representing the heat transfer between the air and the street canyon are integrated into the current numerical model. The prediction accuracy of this model is successfully validated against a published wind tunnel experiment. Then, a series of numerical simulations representing four time scenarios (Morning, Afternoon, Noon and Night) are performed at different Bulk Richardson number (Rb). The results demonstrate that uneven distributed street temperature conditions significantly alters street canyon flow structure and pollutant dispersion characteristics compared with conventional uniform street temperature assumption, especially for the morning event. Moreover, air flow patterns and pollutant dispersion are greatly influenced by diurnal variation of surface temperature under unstable stratification conditions. Furthermore, the residual pollutant in near-ground-zone decreases as Rb increases in noon, afternoon and night events under all studied stability conditions.

  13. Reconciling diurnal features of thermal-andmicrowave-derived land surface temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature (T), a key ingredient for physically-based retrieval algorithms of hydrological states and fluxes, remains a poorly constrained parameter for global scale studies. The main two observational methods to remotely measure T are based on thermal infrared (TIR) observations and p...

  14. Impact of the ocean diurnal cycle on the intraseasonnal variability of Sea Surface Temperatures in the mid-latitudes Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Guemas, V.; Salas-Mélia, D.; Kageyama, M.; Giordani, H.; Voldoire, A.

    2009-04-01

    Some recent studies have shown that the ocean diurnal cycle could increase the intraseasonal variability of the Sea Surface Temperatures (SST) in the tropics (Shinoda and Hendon, 1998; Bernie et al, 2005; Shinoda, 2005). This study aims at extending these analyses to the mid-latitudes. To conduct these analyses, the CNRMOM1D 1-dimensional ocean model is forced with ERA40 reanalysis data with a 1 hour frequency in solar heat flux ( 6h hours for the other forcing fields ). The turbulent vertical mixing scheme (Gaspar et al., 1988) is based on the parameterisation of the second-order turbulent moments expressed as a function of the turbulent kinetic energy. The model has 124 vertical levels with a vertical resolution of 1m near the surface and 500m at the bottom. This high vertical resolution combined with a high temporal forcing resolution allows to simulate a realistic diurnal cycle of the oceanic upper-layers. This experiment is compared with one forced on a daily time-step. By comparing both experiments, the impact of the ocean diurnal cycle on the intraseasonnal variability of sea surface temperature anomalies is assessed. We show that the phase of the SST variability is affected and this impact is strongly associated with the non-linear interactions between the diurnal cycle in mixed layer depth and surface forcings.

  15. Diurnal ocean surface layer model validation

    NASA Technical Reports Server (NTRS)

    Hawkins, Jeffrey D.; May, Douglas A.; Abell, Fred, Jr.

    1990-01-01

    The diurnal ocean surface layer (DOSL) model at the Fleet Numerical Oceanography Center forecasts the 24-hour change in a global sea surface temperatures (SST). Validating the DOSL model is a difficult task due to the huge areas involved and the lack of in situ measurements. Therefore, this report details the use of satellite infrared multichannel SST imagery to provide day and night SSTs that can be directly compared to DOSL products. This water-vapor-corrected imagery has the advantages of high thermal sensitivity (0.12 C), large synoptic coverage (nearly 3000 km across), and high spatial resolution that enables diurnal heating events to be readily located and mapped. Several case studies in the subtropical North Atlantic readily show that DOSL results during extreme heating periods agree very well with satellite-imagery-derived values in terms of the pattern of diurnal warming. The low wind and cloud-free conditions necessary for these events to occur lend themselves well to observation via infrared imagery. Thus, the normally cloud-limited aspects of satellite imagery do not come into play for these particular environmental conditions. The fact that the DOSL model does well in extreme events is beneficial from the standpoint that these cases can be associated with the destruction of the surface acoustic duct. This so-called afternoon effect happens as the afternoon warming of the mixed layer disrupts the sound channel and the propagation of acoustic energy.

  16. An initial estimate of the global distribution of diurnal variation in sea surface salinity

    NASA Astrophysics Data System (ADS)

    Fine, E. C.; Bryan, F. O.; Large, W. G.; Bailey, D. A.

    2015-05-01

    Diurnal variations in sea surface salinity (SSS) have been observed at a few selected locations with adequate in situ instrumentation. Such variations result primarily from imbalances between surface freshwater fluxes and vertical mixing of deeper water to the surface. New observations becoming available from satellite salinity remote sensing missions could help to constrain estimates of diurnal variations in air-sea exchange of freshwater, and provide insight into the processes governing diurnal variability of mixing processes in the upper ocean. Additionally, a better understanding of variation in near surface salinity is required to compare satellite measured SSS with in situ measurements at a few meters depth. The diurnal SSS variations should be reflected as differences between ascending and descending pass retrievals from the Aquarius and SMOS satellites; however, the diurnal signal can be masked by inadequacies of the geophysical corrections used in processing the satellite measurements. In this study, we quantify the expected range of diurnal SSS variations using a model developed for predicting diurnal sea surface temperature variations. We present estimates for the mean and variance of the global diurnal SSS cycle, contrasting it with the diurnal cycle of sea surface temperature. We find the SSS diurnal cycle can be significant throughout the tropics, with mean amplitudes of up to 0.1 psu in areas with heavy precipitation. Predicted maximum diurnal ranges approach 2 psu in select regions. Surface freshening in Aquarius salinity retrievals is shown to be larger for ascending than descending passes, consistent with the expectations from the model simulation.

  17. Diurnal Variation of Meteorological Parameters in the Land Surface Interface

    NASA Astrophysics Data System (ADS)

    Pillai, J. S.

    A pilot land surface processes experiment was conducted at Anand, Gujarat, situated in the western part of India, from April to July 1995. The diurnal variation of air and soil temperature with respect to solar radiation was studied in two selected periods, one in summer and the other during monsoon. It was observed that during summer, there was a considerable lag in the temperature maxima with respect to solar radiation, as compared to the monsoon period. Also, in summer, when there was an increase in wind speed from near zero values in the early morning hours, the soil surface as well as the air temperature minima were raised.

  18. Moored surface buoy observations of the diurnal warm layer

    NASA Astrophysics Data System (ADS)

    Prytherch, J.; Farrar, J. T.; Weller, R. A.

    2013-09-01

    An extensive data set is used to examine the dynamics of diurnal warming in the upper ocean. The data set comprises more than 4700 days of measurements at five sites in the tropics and subtropics, obtained from surface moorings equipped to make comprehensive meteorological, incoming solar and infrared radiation, and high-resolution subsurface temperature (and, in some cases, velocity) measurements. The observations, which include surface warmings of up to 3.4°C, are compared with a selection of existing models of the diurnal warm layer (DWL). A simple one-layer physical model is shown to give a reasonable estimate of both the magnitude of diurnal surface warming (model-observation correlation 0.88) and the structure and temporal evolution of the DWL. Novel observations of velocity shear obtained during 346 days at one site, incorporating high-resolution (1 m) upper ocean (5-15 m) acoustic Doppler current profile measurements, are also shown to be in reasonable agreement with estimates from the physical model (daily maximum shear model-observation correlation 0.77). Physics-based improvements to the one-layer model (incorporation of rotation and freshwater terms) are discussed, though they do not provide significant improvements against the observations reported here. The simplicity and limitations of the physical model are used to discuss DWL dynamics. The physical model is shown to give better model performance under the range of forcing conditions experienced across the five sites than the more empirical models.

  19. Termite mounds harness diurnal temperature oscillations for ventilation

    PubMed Central

    King, Hunter; Ocko, Samuel; Mahadevan, L.

    2015-01-01

    Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diurnal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combination of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ventilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations. PMID:26316023

  20. Termite mounds harness diurnal temperature oscillations for ventilation.

    PubMed

    King, Hunter; Ocko, Samuel; Mahadevan, L

    2015-09-15

    Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diurnal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combination of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ventilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations. PMID:26316023

  1. Spatial patterns in timing of the diurnal temperature cycle

    NASA Astrophysics Data System (ADS)

    Holmes, T. R. H.; Crow, W. T.; Hain, C.

    2013-05-01

    This paper investigates the structural difference in timing of the diurnal temperature cycle (DTC) over land resulting from choice of measuring device or model framework. It is shown that the timing can be reliably estimated from temporally sparse observations acquired from a constellation of low Earth orbiting satellites given record lengths of at least three months. Based on a year of data, the spatial patterns of mean DTC timing are compared between Ka-band temperature estimates, geostationary thermal infrared (TIR) temperature estimates and numerical weather prediction model output from the Global Modeling and Assimilation Office (GMAO). It is found that the spatial patterns can be explained by vegetation effects, sensing depth differences and more speculatively the orientation of orographic relief features. In absolute terms, the GMAO model puts the peak of the DTC on average at 12:50 local solar time, 23 min before TIR with a peak temperature at 13:13. Since TIR is the shallowest observation of the land surface, this small difference represents a structural error that possibly affects the models ability to assimilate observations that are closely tied to the DTC. For non-desert areas, the Ka-band observations have only a small delay of about 15 min with the TIR observations which is in agreement with their respective theoretical sensing depth. The results of this comparison provide insights into the structural differences between temperature measurements and models, and can be used as a first step to account for these differences in a coherent way.

  2. Spatial patterns in timing of the diurnal temperature cycle

    NASA Astrophysics Data System (ADS)

    Holmes, T. R. H.; Crow, W. T.; Hain, C.

    2013-10-01

    This paper investigates the structural difference in timing of the diurnal temperature cycle (DTC) over land resulting from choice of measuring device or model framework. It is shown that the timing can be reliably estimated from temporally sparse observations acquired from a constellation of low Earth-orbiting satellites given record lengths of at least three months. Based on a year of data, the spatial patterns of mean DTC timing are compared between temperature estimates from microwave Ka-band, geostationary thermal infrared (TIR), and numerical weather prediction model output from the Global Modeling and Assimilation Office (GMAO). It is found that the spatial patterns can be explained by vegetation effects, sensing depth differences and more speculatively the orientation of orographic relief features. In absolute terms, the GMAO model puts the peak of the DTC on average at 12:50 local solar time, 23 min before TIR with a peak temperature at 13:13 (both averaged over Africa and Europe). Since TIR is the shallowest observation of the land surface, this small difference represents a structural error that possibly affects the model's ability to assimilate observations that are closely tied to the DTC. The equivalent average timing for Ka-band is 13:44, which is influenced by the effect of increased sensing depth in desert areas. For non-desert areas, the Ka-band observations lag the TIR observations by only 15 min, which is in agreement with their respective theoretical sensing depth. The results of this comparison provide insights into the structural differences between temperature measurements and models, and can be used as a first step to account for these differences in a coherent way.

  3. Projected Increase in Diurnal and Inter-Diurnal Variations of European Summer Temperatures

    NASA Astrophysics Data System (ADS)

    Cattiaux, J.; Douville, H.; Schoetter, R.; Parey, S.; Yiou, P.

    2014-12-01

    The current European warming is expected to be associated with an increased temperature variability in summer, particularly at the daily time-scale. Such an increase would affect hot extremes and accentuate the societal and environmental impacts caused by the mean warming. Here we investigate future changes in the short-term variability of European summer temperatures using two indices that have been seldom documented so far: the variations within one day (diurnal temperature range, DTR) and the variations from one day to the next (inter-diurnal temperature variability, ITV). These rapid variations represent key issues for impact communities, in particular energy providers vulnerable to sudden surges in electricity demand. Besides, the ITV provides a measure of daily variability that is not disturbed by longer-term variations in the mean (e.g., seasonal cycle and/or a multi-year trend), whereas traditional measures such as standard deviation or variance are. We use 21st-century projections performed by 34 models of the CMIP5 ensemble under the three RCP 2.6, 4.5 and 8.5 scenarios. Models are evaluated over the present-day period against the E-OBS dataset. In Europe, both indices of summer temperature variability are projected to increase, with a rather good model agreement on the sign, while uncertainties remain on the amplitude. In particular, we show that extremely high day-to-day and/or diurnal temperature variations are expected to occur more frequently. We highlight the singularity of the European area, since ITV and DTR changes do not systematically coincide over other regions (e.g., the U.S). Then we investigate the physical processes underlying these ITV and DTR changes in the CMIP5 projections. The respective contributions of the summer drying of European soils, the reduction in cloud cover and the changes in large-scale dynamics are estimated. Finally, the possibility of reducing model uncertainties through constraints emerging from both present

  4. Radiative scaling of the nocturnal boundary layer and the diurnal temperature range

    NASA Astrophysics Data System (ADS)

    Betts, Alan K.

    2006-04-01

    A radiative scaling for the warm season nocturnal boundary layer (NBL) is proposed, based on the daily mean surface net longwave radiation flux. Using this scaling, a conceptual model is proposed for the NBL, with parameters estimated from multiple linear regression of model data from the European Centre reanalysis, averaged over river basins from the tropics to high latitudes. A radiative temperature scale, computed from surface net longwave radiation flux and the slope of the Stefan-Boltzmann law, primarily determines the strength of the NBL and the amplitude of the diurnal temperature range, although the length of the nighttime period and the surface wind stress play important subsidiary roles. A related radiative velocity scale or radiative conductance, the duration of the nighttime period and the ratio of the scaled surface heat flux (which increases with wind stress) to the NBL strength determine the depth of the NBL. From an observational perspective, this suggests that the diurnal temperature range may give a useful estimate of surface net longwave radiation flux. From a modeling perspective, this provides a framework for relating model physical parameterizations, especially the coupling at night between the surface, the ground and the atmosphere, to observables, the diurnal temperature range and the strength and depth of the NBL. The model is then applied to estimate the nocturnal rise in concentration of gases such as CO2 and radon that are emitted at the surface.

  5. Diurnal Evolution of Three-Dimensional Wind and Temperature Structure in California's Central Valley

    SciTech Connect

    Zhong, Shiyuan; Whiteman, Charles D.; Bian, Xindi

    2004-11-01

    The diurnal evolution of the three-dimensional summer season mean wind and temperature structure in California’s Sacramento and San Joaquin Valleys (collectively called the Central Valley) are investigated using data from 22 radar wind profiler/Radio Acoustic Sounding Systems (RASS) operated as part of the Central California Ozone Study in 2000. The profiler network revealed, for the first time, that the persistent summer season flow pattern documented by surface observations extends 800-1000 m above the surface. At most locations, up-valley winds persist both day and night except at the upper ends of the valleys and close to the valley sidewalls where diurnal wind reversals occur. Wind speeds exhibit pronounced diurnal oscillations, with amplitudes decreasing with height. A low-level wind maximum occurs in the lowest 300 m, with a sharp decrease in speed above the maximum. Especially well-defined nocturnal low-level jets occur at sites in the southern San Joaquin Valley, where maximum speeds of 10 m s-1 or more occur 1-2 h before midnight at heights near 300 m. The afternoon mixed layer, generally deeper than 1000 m, increases in depth with up-valley distance in both valleys. At night, temperature inversions develop in the lowest several hundred meters with near-isothermal layers above. Mean temperatures in the lowest 500 m of the valleys are always warmer than at the same altitude over the coast, and temperature increases from the lower to upper valleys. The diurnal oscillation of the coast-valley and along-valley temperature and pressure difference reach a maximum in late afternoon and a minimum in early morning. These oscillations are in phase with the diurnal variation of westerly onshore flows. The along-valley wind maxima, however, occur 1-2 h before midnight while the pressure gradient maxima are usually found just before sunset.

  6. Diurnal temperature range over Europe between 1950 and 2005

    NASA Astrophysics Data System (ADS)

    Makowski, K.; Wild, M.; Ohmura, A.

    2008-04-01

    It has been widely accepted that diurnal temperature range (DTR) decreased on a global scale during the second half of the twentieth century. Here we show however, that the long-term trend of annual DTR has reversed from a decrease to an increase during the 1970s in Western Europe and during the 1980s in Eastern Europe. The analysis is based on the high-quality dataset of the European Climate Assessment and Dataset Project, from which we selected approximately 200 stations, covering the area from Iceland to Algeria and from Turkey to Russia for 1950 to 2005. We investigate national and regional annual means as well as the pan-European mean with respect to trends and reversal periods. 17 of the 24 investigated regions including the pan-European mean show a statistical significant increase since 1990 at the latest. Of the remaining 7 regions, 2 show a non-significant increase, 3 a significant decrease and the remaining 2 no significant trend. The long-term change in DTR is governed by both surface shortwave and longwave radiation, the former of which has undergone a change from dimming to brightening. Consequently, we discuss the connections between DTR, shortwave radiation and sulfur emissions which are thought to be amongst the most important factors influencing the incoming solar radiation through the primary and secondary aerosol effect. We find reasonable agreement between trends in SO2 emissions, radiation and DTR in areas affected by high pollution. Consequently, we conclude that the long-term trends in DTR are mostly determined by changes in emissions and the associated changes in incoming solar radiation.

  7. Diurnal temperature range over Europe between 1950 and 2005

    NASA Astrophysics Data System (ADS)

    Makowski, K.; Wild, M.; Ohmura, A.

    2008-11-01

    It has been widely accepted that diurnal temperature range (DTR) decreased on a global scale during the second half of the twentieth century. Here we show however, that the long-term trend of annual DTR has reversed from a decrease to an increase during the 1970s in Western Europe and during the 1980s in Eastern Europe. The analysis is based on the high-quality dataset of the European Climate Assessment and Dataset Project, from which we selected approximately 200 stations covering the area bordered by Iceland, Algeria, Turkey and Russia for the period 1950 to 2005. We investigate national and regional annual means as well as the pan-European mean with respect to trends and reversal periods. 17 of the 24 investigated regions including the pan-European mean show a statistical significant increase of DTR since 1990 at the latest. Of the remaining 7 regions, two show a non-significant increase, three a significant decrease and two no significant trend. Changes in DTR are affected by both surface shortwave and longwave radiation, the former of which has undergone a change from dimming to brightening in the period considered. Consequently, we discuss the connections between DTR, shortwave radiation and sulfur emissions which are thought to be amongst the most important factors influencing the incoming solar radiation through the primary and secondary aerosol effect. We find reasonable agreement between trends in SO2 emissions, radiation and DTR in areas affected by high pollution. Consequently, we conclude that the trends in DTR could be mostly determined by changes in emissions and the associated changes in incoming solar radiation.

  8. Asymmetry in the Diurnal Variation of Surface Albedo

    NASA Technical Reports Server (NTRS)

    Mayor, S.; Smith, W. L., Jr.; Nguyen, L.; Alberta, T. A.; Minnis, P.; Whitlock, C. H.; Schuster, G. L.

    1996-01-01

    Remote sensing of surface properties and estimation of clear-sky and surface albedo generally assumes that the albedo depends only on the solar zenith angle. The effects of dew, frost, and precipitation as well as evaporation and wind can lead to some systematic diurnal variability resulting in an asymmetric diurnal cycle of albedo. This paper examines the symmetry of both surface-observed albedos and top-of-the-atmosphere (TOA) albedos derived from satellite data. Broadband and visible surface albedos were measured at the Department of Energy Atmospheric Radiation Measurement (ARM) Program Southern Great Plains Central Facility, at some fields near the ARM site, and over a coniferous forest in eastern Virginia. Surface and wind conditions are available for most cases. GOES-8 satellite radiance data are converted to broadband albedo using bidirectional reflectance functions and an empirical narrowband-to-broadband relationship. The initial results indicate that surface moisture has a significant effect and can change the albedo in the afternoon by 20% relative to its morning counterpart. Such effects may need to be incorporated in mesoscale and even large-scale models of atmospheric processes.

  9. Removing Diurnal Cycle Contamination in Satellite-Derived Tropospheric Temperatures: Understanding Tropical Tropospheric Trend Discrepancies

    NASA Astrophysics Data System (ADS)

    Po-Chedley, S.; Thorsen, T. J.; Fu, Q.

    2014-12-01

    Tropical mid-tropospheric temperature (TMT) time series have been constructed by several independent research teams using satellite microwave sounding unit (MSU) measurements beginning in 1978 and advanced MSU (AMSU) measurements since 1998. Despite careful efforts to homogenize the MSU/AMSU measurements, tropical TMT trends disagree by a factor of three even though each analysis uses the same basic data. Previous studies suggest that the discrepancy in tropical TMT temperature trends is largely caused by differences in both the NOAA-9 warm target factor and diurnal drift corrections used by various teams to homogenize the MSU/AMSU measurements. This work introduces a new observationally-based method for removing biases related to satellite diurnal drift. The method relies on minimizing inter-satellite and inter-node drifts by subtracting out a common diurnal cycle determined via linear regression. It is demonstrated that this method is effective at removing intersatellite biases and biases between the ascending (PM) and descending (AM) node of individual satellites in the TMT time series. After TMT bias correction, the ratio of tropical tropospheric temperature trends relative to surface temperature trends is in accord with the ratio from global climate models. It is shown that bias corrections for diurnal drift based on a climate model produce tropical trends very similar to those from the observationally-based correction, with a trend differences smaller than 0.02 K decade-1. Differences among various TMT datasets are explored further. Tropical trends from this work are comparable to those from the Remote Sensing System (RSS) and NOAA datasets despite small differences. Larger differences between this work and UAH are attributed to differences in the treatment of the NOAA-9 target factor and the UAH diurnal cycle correction.

  10. The Influence of Diurnal Temperature Variation on Degree-Day Accumulation and Insect Life History

    PubMed Central

    Chen, Shi; Fleischer, Shelby J.; Saunders, Michael C.; Thomas, Matthew B.

    2015-01-01

    Ectotherms, such as insects, experience non-constant temperatures in nature. Daily mean temperatures can be derived from the daily maximum and minimum temperatures. However, the converse is not true and environments with the same mean temperature can exhibit very different diurnal temperate ranges. Here we apply a degree-day model for development of the grape berry moth (Paralobesia viteana, a significant vineyard pest in the northeastern USA) to investigate how different diurnal temperature range conditions can influence degree-day accumulation and, hence, insect life history. We first consider changes in diurnal temperature range independent of changes in mean temperatures. We then investigate grape berry moth life history under potential climate change conditions, increasing mean temperature via variable patterns of change to diurnal temperature range. We predict that diurnal temperature range change can substantially alter insect life history. Altering diurnal temperature range independent of the mean temperature can affect development rate and voltinism, with the magnitude of the effects dependent on whether changes occur to the daily minimum temperature (Tmin), daily maximum temperature (Tmax), or both. Allowing for an increase in mean temperature produces more marked effects on life history but, again, the patterns and magnitude depend on the nature of the change to diurnal temperature range together with the starting conditions in the local environment. The study highlights the importance of characterizing the influence of diurnal temperature range in addition to mean temperature alone. PMID:25790195

  11. A numerical model of nonmigrating diurnal tides between the surface and 65 km

    NASA Technical Reports Server (NTRS)

    Lieberman, Ruth S.; Leovy, Conway B.

    1995-01-01

    Observations of surface pressure and middle atmosphere temperatures and winds indicate that a substantial nonmigrating component is present in the diurnal tide. The nonmigrating tides, which propagate with a zonal phase speed that is different from the earth's rotation, are attributed to the diurnal heating of geographically fixed sources. In this study we utilize a classical tidal model to examine the propagation characteristics of diurnal tides. The global fields of tropospheric sensible, radiative, and latent heating used to drive the model are supplied from summer and winter diurnal climatologies of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM2). A novel aspect of this study is the focus on the relative importance of the nonmigrating components. The classical model successfully reproduces many observed features of the low-latitude diurnal surface pressure tides. In the middle atmosphere, the simulated migrating (or sun-synchronous) tide shows qualitative agreement with November-March Limb Infrared Monitor of the Stratosphere (LIMS) observations. Tropospheric solar heating is clearly the dominant driving force for the migrating tide, with secondary contributions from boundary-layer sensible heating and tropospheric latent heat release. The leading modes of the zonal mean tide are also driven chiefly by tropospheric solar heating. The higher-order modes of the zonal mean and eastward propagating tides may be attributed to the joint effects of tropospheric solar heating, sensible heating, and latent heat release. The LIMS and other data reveal features that cannot be explained or examined within the context of the classical model used in the present study. These include upward phase propagation, vertical attenuation, and temporal variations in the migrating diurnal tide.

  12. Minimum Temperatures, Diurnal Temperature Ranges and Temperature Inversions in Limestone Sinkholes of Different Sizes and Shapes

    SciTech Connect

    Whiteman, Charles D.; Haiden, Thomas S.; Pospichal, Bernhard; Eisenbach, Stefan; Steinacker, Reinhold

    2004-08-01

    Air temperature data from five enclosed limestone sinkholes of various sizes and shapes on the 1300 m MSL Duerrenstein Plateau near Lunz, Austria have been analyzed to determine the effect of sinkhole geometry on temperature minima, diurnal temperature ranges, temperature inversion strengths and vertical temperature gradients. Data were analyzed for a non-snow-covered October night and for a snow-covered December night when the temperature fell as low as -28.5°C. Surprisingly, temperatures were similar in two sinkholes with very different drainage areas and depths. A three-layer model was used to show that the sky-view factor is the most important topographic parameter controlling cooling for basins in this size range and that the cooling slows when net longwave radiation at the floor of the sinkhole is nearly balanced by the ground heat flux.

  13. Diurnal temperature effect on nitrate removal and production efficiency in bedform-induced hyporheic zones

    NASA Astrophysics Data System (ADS)

    Zheng, L.; Cardenas, M. B.

    2014-12-01

    Rivers and aquifers are connected through the hyporheic zone (HZ). Pore water in the subsurface sediments is continuously exchanged with the overlying surface water. The exchange of water, mass and energy occurring along the surface-subsurface interface or within the HZ exerts a strong influence on the quality of both surface and subsurface waters, and fluvial ecology. Moreover, the HZ is rich in biologically active sediment, creating a favorable condition for microbially-facilitated reactions to occur, including organic carbon oxidation (aerobic respiration), nitrification, and denitrification. Inorganic N, especially NO3-, is of concern as a drinking water pollutant and as a cause for eutrophication that threatens ecosystems. The biogeochemical reactions in the HZ could produce or consume NO3- and thus the HZ could serve a nitrate source or sink role in the fluvial system. In addition, hyporheic exchange across the sediment-water interface (SWI) leads to penetration of diel temperature cycles from the river, leading to dynamic HZ temperature pattern. This in turn affects biogeochemical reactions in the HZ. The main objective of this study is to integrate all the processes that occur along the SWI to understand how diurnal temperature variations affect the biogeochemical function of the HZ. We conducted numerical simulations of coupled turbulent open-channel fluid flow, porous fluid flow, porous heat transport and reactive solute transport to study feedbacks and coupling between these processes. We assumed sinusoidally varying diurnal temperature variations. We studied the effects of different mean temperatures and different amplitudes of the diurnal temperature variations on nitrate removal or production efficiency in the HZ. The simulation results show that the average temperature effect on the HZ nitrate source-sink functionality and its associated efficiency has strong dependence on the [NO3-]/[NH4+ ] ratio in the river. However, the effects of the

  14. Large diurnal temperature range increases bird sensitivity to climate change

    PubMed Central

    Briga, Michael; Verhulst, Simon

    2015-01-01

    Climate variability is changing on multiple temporal scales, and little is known of the consequences of increases in short-term variability, particularly in endotherms. Using mortality data with high temporal resolution of zebra finches living in large outdoor aviaries (5 years, 359.220 bird-days), we show that mortality rate increases almost two-fold per 1°C increase in diurnal temperature range (DTR). Interestingly, the DTR effect differed between two groups with low versus high experimentally manipulated foraging costs, reflecting a typical laboratory ‘easy’ foraging environment and a ‘hard’ semi-natural environment respectively. DTR increased mortality on days with low minimum temperature in the easy foraging environment, but on days with high minimum temperature in the semi-natural environment. Thus, in a natural environment DTR effects will become increasingly important in a warming world, something not detectable in an ‘easy’ laboratory environment. These effects were particularly apparent at young ages. Critical time window analyses showed that the effect of DTR on mortality is delayed up to three months, while effects of minimum temperature occurred within a week. These results show that daily temperature variability can substantially impact the population viability of endothermic species. PMID:26563993

  15. Recent variations in mean temperature and the diurnal temperature range in the Antarctic

    SciTech Connect

    Jones, P.D.

    1995-06-01

    Monthly mean surface temperature data are available from nearly twenty stations for the period since the International Geophysical Year 1957. All but three stations show an increase in mean temperatures over this time, amounting in the average to 0.57{degrees}C over 1957 to 1994. All of this warming occurred before the early 1970s. Since then, there has been no change. The warming has been greatest in the Antarctic Peninsula. Analyses of the less-widely available diurnal temperature range (DTR) (maximum-minimum) data show regions of increase and decrease over Antarctica. An average continental DTR series shows no trend over 1957 to 1992. Analyses for six mid-to-high latitude Southern Ocean islands show increase in mean temperature over 1961-90. Given the low year-to-year variability in these data, these trends are more significant than for any of the stations on the Antarctic continent. The marked decrease in mean temperatures over Antarctica during 1993 and 1994 seems unrelated to sea-ice variations which show little change since the early 1980s. 17 refs., 4 figs., 1 tab.

  16. Understanding the Greenhouse Effect Using Clear vs Cloudy Sky Diurnal Temperature Observations

    NASA Astrophysics Data System (ADS)

    Tayor, S. V.

    2006-12-01

    Standard meteorological observations from local airports can provide a tangible example of how the greenhouse effect is a part of everyday life. In the exercise outlined here, students plot diurnal temperature observations to compare the relative magnitude of the greenhouse effect under clear and cloudy-sky conditions, gaining insight into the strength of the greenhouse effect. Contemplation of the relation of surface temperature and humidity with cloud cover leads to a further understading of important atmospheric processes involving the Clausius-Clapeyron equation and terrestrial and solar radiation effects.

  17. Practical limitations on the use of diurnal temperature signals to quantify groundwater upwelling

    USGS Publications Warehouse

    Briggs, Martin; Lautz, Laura K.; Buckley, Sean F.; Lane, Jr., John W.

    2014-01-01

    Groundwater upwelling to streams creates unique habitat by influencing stream water quality and temperature; upwelling zones also serve as vectors for contamination when groundwater is degraded. Temperature time series data acquired along vertical profiles in the streambed have been applied to simple analytical models to determine rates of vertical fluid flux. These models are based on the downward propagation characteristics (amplitude attenuation and phase-lag) of the surface diurnal signal. Despite the popularity of these models, there are few published characterizations of moderate-to-strong upwelling. We attribute this limitation to the thermodynamics of upwelling, under which the downward conductive signal transport from the streambed interface occurs opposite the upward advective fluid flux. Governing equations describing the advection–diffusion of heat within the streambed predict that under upwelling conditions, signal amplitude attenuation will increase, but, counterintuitively, phase-lag will decrease. Therefore the extinction (measurable) depth of the diurnal signal is very shallow, but phase lag is also short, yielding low signal to noise ratio and poor model sensitivity. Conversely, amplitude attenuation over similar sensor spacing is strong, yielding greater potential model sensitivity. Here we present streambed thermal time series over a range of moderate to strong upwelling sites in the Quashnet River, Cape Cod, Massachusetts. The predicted inverse relationship between phase-lag and rate of upwelling was observed in the field data over a range of conditions, but the observed phase-lags were consistently shorter than predicted. Analytical solutions for fluid flux based on signal amplitude attenuation return results consistent with numerical models and physical seepage meters, but the phase-lag analytical model results are generally unreasonable. Through numerical modeling we explore reasons why phase-lag may have been over-predicted by the

  18. The association between diurnal temperature range and childhood bacillary dysentery.

    PubMed

    Wen, Li-ying; Zhao, Ke-fu; Cheng, Jian; Wang, Xu; Yang, Hui-hui; Li, Ke-sheng; Xu, Zhi-wei; Su, Hong

    2016-02-01

    Previous studies have found that mean, maximum, and minimum temperatures were associated with bacillary dysentery (BD). However, little is known about whether the within-day variation of temperature has any impact on bacillary dysentery. The current study aimed to identify the relationship between diurnal temperature range (DTR) and BD in Hefei, China. Daily data on BD counts among children aged 0-14 years from 1 January 2006 to 31 December 2012 were retrieved from Hefei Center for Disease Control and Prevention. Daily data on ambient temperature and relative humidity covering the same period were collected from the Hefei Bureau of Meteorology. A Poisson generalized linear regression model combined with a distributed lag non-linear model (DLNM) was used in the analysis after controlling the effects of season, long-term trends, mean temperature, and relative humidity. The results showed that there existed a statistically significant relationship between DTR and childhood BD. The DTR effect on childhood bacillary dysentery increased when DTR was over 8 °C. And it was greatest at 1-day lag, with an 8% (95% CI = 2.9-13.4%) increase of BD cases per 5 °C increment of DTR. Male children and children aged 0-5 years appeared to be more vulnerable to the DTR effect. The data indicate that large DTR may increase the incidence of childhood BD. Caregivers and health practitioners should be made aware of the potential threat posed by large DTR. Therefore, DTR should be taken into consideration when making targeted health policies and programs to protect children from being harmed by climate impacts. PMID:26045331

  19. The association between diurnal temperature range and childhood bacillary dysentery

    NASA Astrophysics Data System (ADS)

    Wen, Li-ying; Zhao, Ke-fu; Cheng, Jian; Wang, Xu; Yang, Hui-hui; Li, Ke-sheng; Xu, Zhi-wei; Su, Hong

    2016-02-01

    Previous studies have found that mean, maximum, and minimum temperatures were associated with bacillary dysentery (BD). However, little is known about whether the within-day variation of temperature has any impact on bacillary dysentery. The current study aimed to identify the relationship between diurnal temperature range (DTR) and BD in Hefei, China. Daily data on BD counts among children aged 0-14 years from 1 January 2006 to 31 December 2012 were retrieved from Hefei Center for Disease Control and Prevention. Daily data on ambient temperature and relative humidity covering the same period were collected from the Hefei Bureau of Meteorology. A Poisson generalized linear regression model combined with a distributed lag non-linear model (DLNM) was used in the analysis after controlling the effects of season, long-term trends, mean temperature, and relative humidity. The results showed that there existed a statistically significant relationship between DTR and childhood BD. The DTR effect on childhood bacillary dysentery increased when DTR was over 8 °C. And it was greatest at 1-day lag, with an 8 % (95 % CI = 2.9-13.4 %) increase of BD cases per 5 °C increment of DTR. Male children and children aged 0-5 years appeared to be more vulnerable to the DTR effect. The data indicate that large DTR may increase the incidence of childhood BD. Caregivers and health practitioners should be made aware of the potential threat posed by large DTR. Therefore, DTR should be taken into consideration when making targeted health policies and programs to protect children from being harmed by climate impacts.

  20. Changes in diurnal temperature range and national cereal yields

    SciTech Connect

    Lobell, D

    2007-04-26

    Models of yield responses to temperature change have often considered only changes in average temperature (Tavg), with the implicit assumption that changes in the diurnal temperature range (DTR) can safely be ignored. The goal of this study was to evaluate this assumption using a combination of historical datasets and climate model projections. Data on national crop yields for 1961-2002 in the 10 leading producers of wheat, rice, and maize were combined with datasets on climate and crop locations to evaluate the empirical relationships between Tavg, DTR, and crop yields. In several rice and maize growing regions, including the two major nations for each crop, there was a clear negative response of yields to increased DTR. This finding reflects a nonlinear response of yields to temperature, which likely results from greater water and heat stress during hot days. In many other cases, the effects of DTR were not statistically significant, in part because correlations of DTR with other climate variables and the relatively short length of the time series resulted in wide confidence intervals for the estimates. To evaluate whether future changes in DTR are relevant to crop impact assessments, yield responses to projected changes in Tavg and DTR by 2046-2065 from 11 climate models were estimated. The mean climate model projections indicated an increase in DTR in most seasons and locations where wheat is grown, mixed projections for maize, and a general decrease in DTR for rice. These mean projections were associated with wide ranges that included zero in nearly all cases. The estimated impacts of DTR changes on yields were generally small (<5% change in yields) relative to the consistently negative impact of projected warming of Tavg. However, DTR changes did significantly affect yield responses in several cases, such as in reducing US maize yields and increasing India rice yields. Because DTR projections tend to be positively correlated with Tavg, estimates of yields

  1. Diurnal temperature range over Europe between 1950 and 2005

    NASA Astrophysics Data System (ADS)

    Makowski, K.; Wild, M.; Ohmura, A.

    2007-12-01

    It has been widely accepted that diurnal temperature range (DTR) decreased on a global scale for the second half of the twentieth century. In contrast, we show that the long-term trend has reversed from decrease to increase during the 1970s in Western Europe and during the 1980s in Eastern Europe. The analysis is based on the high- quality dataset of the European Climate Assessment and Dataset Project, from which we selected about 200 stations, covering the area from Iceland to Algeria and from Turkey to the European part of Russia for 1950 to 2005. We investigate national and regional means as well as the pan-European mean with respect to trends and reversal periods. 17 of the 24 investigated regions including the pan-European mean show a significant increase since 1990 at the latest. Of the remaining 7 regions, 2 show a non-significant increase, 3 a significant decrease and the remaining 2 no significant trend. The long-term change in DTR is considered to depend on both, incoming shortwave radiation and outgoing long-wave radiation, the former of which has undergone a change from dimming to brightening. Consequently we discuss the connections between DTR, shortwave radiation and sulfur emissions which are thought to be amongst the most important factors influencing the incoming solar radiation through the primary and secondary aerosol effect. We find reasonable agreement between trends in SO2 emissions, radiation and DTR in areas affected by high pollution. Consequently we conclude that the long- term trends in DTR are mostly determined by emissions and the incoming solar radiation.

  2. Spring leaf phenology and the diurnal temperature range in a temperate maple forest

    NASA Astrophysics Data System (ADS)

    Hanes, Jonathan M.

    2014-03-01

    Spring leaf phenology in temperate climates is intricately related to numerous aspects of the lower atmosphere [e.g., surface energy balance, carbon flux, humidity, the diurnal temperature range (DTR)]. To further develop and improve the accuracy of ecosystem and climate models, additional investigations of the specific nature of the relationships between spring leaf phenology and various ecosystem and climate processes are required in different environments. This study used visual observations of maple leaf phenology, below-canopy light intensities, and micrometeorological data collected during the spring seasons of 2008, 2009, and 2010 to examine the potential influence of leaf phenology on a seasonal transition in the trend of the DTR. The timing of a reversal in the DTR trend occurred near the time when the leaves were unfolding and expanding. The results suggest that the spring decline in the DTR can be attributed primarily to the effect of canopy closure on daily maximum temperature. These findings improve our understanding of the relationship between leaf phenology and the diurnal temperature range in temperate maple forests during the spring. They also demonstrate the necessity of incorporating accurate phenological data into ecosystem and climate models and warrant a careful examination of the extent to which canopy phenology is currently incorporated into existing models.

  3. Modeling diurnal land temperature cycles over Los Angeles using downscaled GOES imagery

    NASA Astrophysics Data System (ADS)

    Weng, Qihao; Fu, Peng

    2014-11-01

    Land surface temperature is a key parameter for monitoring urban heat islands, assessing heat related risks, and estimating building energy consumption. These environmental issues are characterized by high temporal variability. A possible solution from the remote sensing perspective is to utilize geostationary satellites images, for instance, images from Geostationary Operational Environmental System (GOES) and Meteosat Second Generation (MSG). These satellite systems, however, with coarse spatial but high temporal resolution (sub-hourly imagery at 3-10 km resolution), often limit their usage to meteorological forecasting and global climate modeling. Therefore, how to develop efficient and effective methods to disaggregate these coarse resolution images to a proper scale suitable for regional and local studies need be explored. In this study, we propose a least square support vector machine (LSSVM) method to achieve the goal of downscaling of GOES image data to half-hourly 1-km LSTs by fusing it with MODIS data products and Shuttle Radar Topography Mission (SRTM) digital elevation data. The result of downscaling suggests that the proposed method successfully disaggregated GOES images to half-hourly 1-km LSTs with accuracy of approximately 2.5 K when validated against with MODIS LSTs at the same over-passing time. The synthetic LST datasets were further explored for monitoring of surface urban heat island (UHI) in the Los Angeles region by extracting key diurnal temperature cycle (DTC) parameters. It is found that the datasets and DTC derived parameters were more suitable for monitoring of daytime- other than nighttime-UHI. With the downscaled GOES 1-km LSTs, the diurnal temperature variations can well be characterized. An accuracy of about 2.5 K was achieved in terms of the fitted results at both 1 km and 5 km resolutions.

  4. Contrasting spatial patterns in the diurnal and semidiurnal temperature variability in the Santa Barbara Channel, California

    NASA Astrophysics Data System (ADS)

    Aristizábal, María. F.; Fewings, Melanie R.; Washburn, Libe

    2016-01-01

    The Santa Barbara Channel, California, experiences large temperature fluctuations during summer that have been associated with the input of nutrients to the euphotic zone. We studied the temperature fluctuations in the diurnal and semidiurnal bands, which account for as much as 65% of the total variance. We analyzed data from 25 moorings along the mainland and the Northern Channel Islands deployed at depths 8-18 m during 1999-2012. In the diurnal band, the temperature fluctuations vary almost simultaneously within two distinct regions, with a lag of 5 h between the regions: the mainland east of Point Conception and the west part of the Channel exposed to the large-scale winds. The two regions of in-phase temperature variability are in agreement with a previously published division of zones according to the wind characteristics. The portion of the diurnal temperature variance that is wind driven does not propagate along the coastline, but rather is directly forced by the wind. The semidiurnal temperature oscillations are more substantial in the Northern Channel Islands. These findings are consistent with a numerical study that predicted that the steep slopes of the Santa Cruz Basin, located south of the Channel Islands, are a source of semidiurnal internal tides. We conclude that the contrast between the spatial patterns of the diurnal and semidiurnal temperature oscillations on scales of tens of kilometers reflects the spatial distribution of the main forcing in each band, namely the diurnal wind and the locally generated semidiurnal internal tide. The spatial patterns of the diurnal and semidiurnal oscillations reflect the forcing in each band.

  5. Diurnal temperature range compression hastens berry development and modifies flavonoid partitioning in grapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temperatures during the day and night are known to influence grape berry metabolism and resulting composition. In this study, the flavonoid composition of field-grown Vitis vinifera L. cv. Merlot berries was investigated as a function of diurnal temperature range (DTR). The DTR was compressed by c...

  6. Ozone reaction with interior building materials: Influence of diurnal ozone variation, temperature and humidity

    NASA Astrophysics Data System (ADS)

    Rim, Donghyun; Gall, Elliott T.; Maddalena, Randy L.; Nazaroff, William W.

    2016-01-01

    Elevated tropospheric ozone concentrations are associated with increased morbidity and mortality. Indoor ozone chemistry affects human exposure to ozone and reaction products that also may adversely affect health and comfort. Reactive uptake of ozone has been characterized for many building materials; however, scant information is available on how diurnal variation of ambient ozone influences ozone reaction with indoor surfaces. The primary objective of this study is to investigate ozone-surface reactions in response to a diurnally varying ozone exposure for three common building materials: ceiling tile, painted drywall, and carpet tile. A secondary objective is to examine the effects of air temperature and humidity. A third goal is to explore how conditioning of materials in an occupied office building might influence subsequent ozone-surface reactions. Experiments were performed at bench-scale with inlet ozone concentrations varied to simulate daytime (ozone elevated) and nighttime (ozone-free in these experiments) periods. To simulate office conditions, experiments were conducted at two temperatures (22 °C and 28 °C) and three relative humidity values (25%, 50%, 75%). Effects of indoor surface exposures were examined by placing material samples in an occupied office and repeating bench-scale characterization after exposure periods of 1 and 2 months. Deposition velocities were observed to be highest during the initial hour of ozone exposure with slow decrease in the subsequent hours of simulated daytime conditions. Daily-average ozone reaction probabilities for fresh materials are in the respective ranges of (1.7-2.7) × 10-5, (2.8-4.7) × 10-5, and (3.0-4.5) × 10-5 for ceiling tile, painted drywall, and carpet tile. The reaction probability decreases by 7%-47% across the three test materials after two 8-h periods of ozone exposure. Measurements with the samples from an occupied office reveal that deposition velocity can decrease or increase with time

  7. Epithermal Neutron Evidence for a Diurnal Surface Hydration Process in the Moon's High Latitudes

    NASA Technical Reports Server (NTRS)

    McClanahan, T. P.; Mitrofanov, I. G.; Boynton, W. V.; Chin, G.; Parsons, A.; Starr, R. D.; Evans, L. G.; Sanin, A.; Litvak, M.; Livengood, T.

    2015-01-01

    We report evidence from epithermal neutron flux observations that show that the Moon's high latitude surfaces are being actively hydrated, dehydrated and rehydrated in a diurnal cycle. The near-surface hydration is indicated by an enhanced suppression of the lunar epithermal neutron leakage flux on the dayside of the dawn terminator on poleward-facing slopes (PFS). At 0600 to 0800 local-time, hydrogen concentrations within the upper 1 meter of PFS are observed to be maximized relative to equivalent equator-facing slopes (EFS). During the lunar day surface hydrogen concentrations diminish towards dusk and then rebuild overnight. Surface hydration is determined by differential comparison of the averaged EFS to PFS epithermal neutron count rates above +/- 75 deg latitude. At dawn the contrast bias towards PFS is consistent with at least 15 to 25 parts-per-million (ppm) hydrogen that dissipates by dusk. We review several lines of evidence derived from temperature and epithermal neutron data by a correlated analysis of observations from the Lunar Reconnaissance Orbiter's (LRO) Lunar Exploration Neutron Detector (LEND) that were mapped as a function of lunar local-time, Lunar Observing Laser Altimeter (LOLA) topography and Diviner (DLRE) surface temperature.

  8. Trend Detection in Regional-Mean Temperature Series: Maximum, Minimum, Mean, Diurnal Range, and SST.

    NASA Astrophysics Data System (ADS)

    Zheng, Xiaogu; Basher, Reid E.; Thompson, Craig S.

    1997-02-01

    Regional climate trends are of interest both for understanding natural climate processes and as tests of anthropogenic climate change signatures. Relative to global trends, however, their detection is hampered by smaller datasets and the influence of regional climate processes such as the Southern Oscillation. Regional trends are often presented by authors without demonstration of statistical significance. In this paper, regional-average annual series of air temperature and sea surface temperature for the New Zealand region are analyzed using a systematic statistical approach that selects the optimum statistical model (with respect to serial correlation, linearity, etc.), explicitly models the interannual variability associated with observable regional climate processes, and tests significance. It is found that the residuals are stationary and are a red noise process [ARMA(1,0)] for all the series examined. The SOI and a meridional circulation anomaly index (both high-pass filtered) are `explanatory variables' for interannual variability. For national-average air temperature (AT), linear and exponential trend models are equally valid but for simplicity the linear model is preferred. Failure to model the serial correlation in AT would result in an estimated confidence interval for trend that is too small by 36%. The use of the explanatory variables tightens the confidence interval by 15%.Significant trends were detected. The trend in AT for 1896-1994 is 0.11 ± 0.035°C decade1 (95% confidence interval). This is about double the trend reported for global data, which may be due to the relative absence of sulfate aerosols in the South Pacific region. The trends in maximum and minimum temperature over this period are not statistically different. However, for the later period of 1951-90, the trend in maximum temperature reduces to an insignificant value, while the trend in minimum temperature remains high, resulting in a significant downward trend in diurnal range of 0

  9. Diurnal temperature variations affect development of a herbivorous arthropod pest and its predators.

    PubMed

    Vangansbeke, Dominiek; Audenaert, Joachim; Nguyen, Duc Tung; Verhoeven, Ruth; Gobin, Bruno; Tirry, Luc; De Clercq, Patrick

    2015-01-01

    The impact of daily temperature variations on arthropod life history remains woefully understudied compared to the large body of research that has been carried out on the effects of constant temperatures. However, diurnal varying temperature regimes more commonly represent the environment in which most organisms thrive. Such varying temperature regimes have been demonstrated to substantially affect development and reproduction of ectothermic organisms, generally in accordance with Jensen's inequality. In the present study we evaluated the impact of temperature alternations at 4 amplitudes (DTR0, +5, +10 and +15°C) on the developmental rate of the predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus McGregor (Acari: Phytoseiidae) and their natural prey, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae). We have modelled their developmental rates as a function of temperature using both linear and nonlinear models. Diurnally alternating temperatures resulted in a faster development in the lower temperature range as compared to their corresponding mean constant temperatures, whereas the opposite was observed in the higher temperature range. Our results indicate that Jensen's inequality does not suffice to fully explain the differences in developmental rates at constant and alternating temperatures, suggesting additional physiological responses play a role. It is concluded that diurnal temperature range should not be ignored and should be incorporated in predictive models on the phenology of arthropod pests and their natural enemies and their performance in biological control programmes. PMID:25874697

  10. Automated field detection of rock fracturing, microclimate, and diurnal rock temperature and strain fields

    NASA Astrophysics Data System (ADS)

    Warren, K.; Eppes, M.-C.; Swami, S.; Garbini, J.; Putkonen, J.

    2013-07-01

    The rates and processes that lead to non-tectonic rock fracture on the Earth's surface are widely debated but poorly understood. Few, if any, studies have made the direct observations of rock fracturing under natural conditions that are necessary to directly address this problem. An instrumentation design that enables concurrent high spatial and temporal monitoring resolution of (1) diurnal environmental conditions of a natural boulder and its surroundings in addition to (2) the fracturing of that boulder under natural full-sun exposure is described herein. The surface of a fluvially transported granite boulder was instrumented with (1) six acoustic emission (AE) sensors that record micro-crack associated, elastic wave-generated activity within the three-dimensional space of the boulder, (2) eight rectangular rosette foil strain gages to measure surface strain, (3) eight thermocouples to measure surface temperature, and (4) one surface moisture sensor. Additionally, a soil moisture probe and a full weather station that measures ambient temperature, relative humidity, wind speed, wind direction, barometric pressure, insolation, and precipitation were installed adjacent to the test boulder. AE activity was continuously monitored by one logger while all other variables were acquired by a separate logger every 60 s. The protocols associated with the instrumentation, data acquisition, and analyses are discussed in detail. During the first four months, the deployed boulder experienced almost 12 000 AE events, the majority of which occur in the afternoon when temperatures are decreasing. This paper presents preliminary data that illustrates data validity and typical patterns and behaviors observed. This system offers the potential to (1) obtain an unprecedented record of the natural conditions under which rocks fracture and (2) decipher the mechanical processes that lead to rock fracture at a variety of temporal scales under a range of natural conditions.

  11. Automated field detection of rock fracturing, microclimate, and diurnal rock temperature and strain fields

    NASA Astrophysics Data System (ADS)

    Warren, K.; Eppes, M.-C.; Swami, S.; Garbini, J.; Putkonen, J.

    2013-11-01

    The rates and processes that lead to non-tectonic rock fracture on Earth's surface are widely debated but poorly understood. Few, if any, studies have made the direct observations of rock fracturing under natural conditions that are necessary to directly address this problem. An instrumentation design that enables concurrent high spatial and temporal monitoring resolution of (1) diurnal environmental conditions of a natural boulder and its surroundings in addition to (2) the fracturing of that boulder under natural full-sun exposure is described herein. The surface of a fluvially transported granite boulder was instrumented with (1) six acoustic emission (AE) sensors that record micro-crack associated, elastic wave-generated activity within the three-dimensional space of the boulder, (2) eight rectangular rosette foil strain gages to measure surface strain, (3) eight thermocouples to measure surface temperature, and (4) one surface moisture sensor. Additionally, a soil moisture probe and a full weather station that measures ambient temperature, relative humidity, wind speed, wind direction, barometric pressure, insolation, and precipitation were installed adjacent to the test boulder. AE activity was continuously monitored by one logger while all other variables were acquired by a separate logger every 60 s. The protocols associated with the instrumentation, data acquisition, and analysis are discussed in detail. During the first four months, the deployed boulder experienced almost 12 000 AE events, the majority of which occur in the afternoon when temperatures are decreasing. This paper presents preliminary data that illustrates data validity and typical patterns and behaviors observed. This system offers the potential to (1) obtain an unprecedented record of the natural conditions under which rocks fracture and (2) decipher the mechanical processes that lead to rock fracture at a variety of temporal scales under a range of natural conditions.

  12. Reassessing changes in diurnal temperature range: A new data set and characterization of data biases

    NASA Astrophysics Data System (ADS)

    Thorne, P. W.; Menne, M. J.; Williams, C. N.; Rennie, J. J.; Lawrimore, J. H.; Vose, R. S.; Peterson, T. C.; Durre, I.; Davy, R.; Esau, I.; Klein-Tank, A. M. G.; Merlone, A.

    2016-05-01

    It has been a decade since changes in diurnal temperature range (DTR) globally have been assessed in a stand-alone data analysis. The present study takes advantage of substantively improved basic data holdings arising from the International Surface Temperature Initiative's databank effort and applies the National Centers for Environmental Information's automated pairwise homogeneity assessment algorithm to reassess DTR records. It is found that breakpoints are more prevalent in DTR than other temperature elements and that the resulting adjustments have a broader distribution. This strongly implies that there is an overarching tendency, across the global meteorological networks, for nonclimatic artifacts to impart either random or anticorrelated rather than correlated biases in maximum and minimum temperature series. Future homogenization efforts would likely benefit from simultaneous consideration of DTR and maximum and minimum temperatures, in addition to average temperatures. Estimates of change in DTR are relatively insensitive to whether adjustments are calculated directly or inferred from adjustments returned for the maximum and minimum temperature series. The homogenized series exhibit a reduction in DTR since the midtwentieth century globally (-0.044 K/decade). Adjustments serve to approximately halve the long-term global reduction in DTR in the basic "raw" data. Most of the estimated DTR reduction occurred over 1960-1980. In several regions DTR has apparently increased over 1979-2012, while globally it has exhibited very little change (-0.016 K/decade). Estimated changes in DTR are an order of magnitude smaller than in maximum and minimum temperatures, which have both been increasing rapidly on multidecadal timescales (0.186 K/decade and 0.236 K/decade, respectively, since the midtwentieth century).

  13. The Diurnal Cycle of the Boundary Layer, Convection, Clouds, and Surface Radiation in a Coastal Monsoon Environment (Darwin Australia)

    SciTech Connect

    May, Peter T.; Long, Charles N.; Protat, Alain

    2012-08-01

    The diurnal variation of convection and associated cloud and radiative properties remains a significant issue in global NWP and climate models. This study analyzes observed diurnal variability of convection in a coastal monsoonal environment examining the interaction of convective rain clouds, their associated cloud properties, and the impact on the surface radiation and corresponding boundary layer structure during periods where convection is suppressed or active on the large scale. The analysis uses data from the Tropical Warm Pool International Cloud Experiment (TWP-ICE) as well as routine measurements from the Australian Bureau of Meteorology and the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program. Both active monsoonal and large-scale suppressed (buildup and break) conditions are examined and demonstrate that the diurnal variation of rainfall is much larger during the break periods and the spatial distribution of rainfall is very different between the monsoon and break regimes. During the active monsoon the total net radiative input to the surface is decreased by more than 3 times the amount than during the break regime - this total radiative cloud forcing is found to be dominated by the shortwave (SW) cloud effects because of the much larger optical thicknesses and persistence of long-lasting anvils and cirrus cloud decks associated with the monsoon regime. These differences in monsoon versus break surface radiative energy contribute to low-level air temperature differences in the boundary layer over the land surfaces.

  14. Large diurnal temperature fluctuations negatively influence Aedes aegypti (Diptera: Culicidae) life-history traits.

    PubMed

    Carrington, Lauren B; Seifert, Stephanie N; Willits, Neil H; Lambrechts, Louis; Scott, Thomas W

    2013-01-01

    Seasonal variation in dengue virus transmission in northwestern Thailand is inversely related to the magnitude of diurnal temperature fluctuations, although mean temperature does not vary significantly across seasons. We tested the hypothesis that diurnal temperature fluctuations negatively influence epidemiologically important life-history traits of the primary dengue vector, Aedes aegypti (L.), compared with a constant 26 degrees C temperature. A large diurnal temperature range (DTR) (approximately equals 18 degrees C daily swing) extended immature development time (>1 d), lowered larval survival (approximately equals 6%), and reduced adult female reproductive output by 25% 14 d after blood feeding, relative to the constant 26 degreesC temperature. A small DTR (approximately equal 8 degrees C daily swing) led to a negligible or slightly positive effect on the life history traits tested. Our results indicate that there is a negative impact of large DTR on mosquito biology and are consistent with the hypothesis that, in at least some locations, large temperature fluctuations contribute to seasonal reduction in dengue virus transmission. PMID:23427651

  15. Diurnal tide in the equatorial middle atmosphere as seen in LIMS temperatures

    NASA Technical Reports Server (NTRS)

    Hitchman, M. H.; Leovy, C. B.

    1985-01-01

    The distribution of day-night temperature differences in the middle atmosphere determined by the Nimbus 7 LIMS experiment is described. Day-night differences maximize at and are approximately symmetric about the equator. Successive centers of opposite sign increase in amplitude with altitude, the pattern having a vertical wavelength of approximately 25 km. Profiles of rocket meridional wind at Kwajalein (8.7 deg N) and Ascension Island (8.0 deg S) taken near local noon and averaged over the LIMS data period, exhibit maxima which support the tidal interpretation of the equatorial temperature pattern. These characteristics are in general agreement with previous observational and theoretical results for the solar driven diurnal tide. Substantial time variations in amplitude and in location of the temperature maxima are observed. The diurnal tide near the equatorial stratopause appears to be influenced by the phase of the semiannual oscillation.

  16. Impact of Reduced Diurnal Temperature Range (DTR) on Grassland Mesocosms

    NASA Astrophysics Data System (ADS)

    Gregg, J. W.; Phillips, C.; Wilson, J.

    2010-12-01

    There has been considerable variation in the magnitude of change in diel temperature range due to on-going global warming and ecological responses are poorly understood. We compared the effects of +3.5C higher temperatures distributed either symmetrically (SYM, continuously +3.5C) or asymmetrically (ASYM, +5C dawn Tmin ramped to +2C midday Tmax and back) on planted native perennial grassland communities in climate-controlled chambers (14 spp. including grasses/forbs, annuals/perennials, N-fixers/not). Here, we present an overview of NPP, phenology, community composition, and whole ecosystem gas exchange results. Biomass was greater for both SYM and ASYM treatments during the fall and winter in all three years (+28-70%). However, spring growth was truncated for the warmer treatments due to reduced soil moisture which provided several extra weeks growth for AMB treatments to ‘catch-up’ to that of SYM and ASYM. Peak spring production and flowering were shifted 1-3 weeks earlier for SYM and ASYM treatments, resulting in a concomitant decrease in water use efficiency concomitant with increased soil moisture as measured via δ13C and whole ecosystem gas exchange (CER)/ evapotranspiration. CER measurements also showed the shift in timing of production and no difference in annual C assimilation between AMB, SYM and ASYM treatments. However, annual net ecosystem production (NEP) was negative for SYM and ASYM treatments which pointed towards the likely importance of changes in stored SOM. Mortality was 70% greater for SYM and ASYM treatments in the first year and remained greater through the three years of treatment application resulting in a decline in species diversity. Differential mortality was most apparent in the forb functional group with 50% of species affected. Survival of graminoid species was generally higher with no significant differences between treatments, resulting in a shift in functional group density and LAI to favor grass species in both warming

  17. On the Trend of the Annual Mean, Maximum, and Minimum Temperature and the Diurnal Temperature Range in the Armagh Observatory, Northern Ireland, Dataset, 1844 -2012

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2013-01-01

    Examined are the annual averages, 10-year moving averages, decadal averages, and sunspot cycle (SC) length averages of the mean, maximum, and minimum surface air temperatures and the diurnal temperature range (DTR) for the Armagh Observatory, Northern Ireland, during the interval 1844-2012. Strong upward trends are apparent in the Armagh surface-air temperatures (ASAT), while a strong downward trend is apparent in the DTR, especially when the ASAT data are averaged by decade or over individual SC lengths. The long-term decrease in the decadaland SC-averaged annual DTR occurs because the annual minimum temperatures have risen more quickly than the annual maximum temperatures. Estimates are given for the Armagh annual mean, maximum, and minimum temperatures and the DTR for the current decade (2010-2019) and SC24.

  18. Seasonal Cycle of the Near-Surface Diurnal Wind Field Over the Bay of La Paz, Mexico

    NASA Astrophysics Data System (ADS)

    Turrent, Cuauhtémoc; Zaitsev, Oleg

    2014-05-01

    The results of numerical simulations of the troposphere over the Bay of La Paz, calculated for the months of January, April, July and October during the period 2006-2010 with the Weather Research and Forecast (WRF v3.5) regional model, are used to describe the seasonal features of the diurnal cycle of planetary boundary-layer winds. Two distinct near-surface diurnal flows with strong seasonal variability were identified: (1) a nocturnal and matutinal breeze directed from the subtropical Pacific Ocean, over the Baja California peninsula and the Bay of La Paz, into the Gulf of California that is associated with the regional sea-surface temperature difference between those two major water bodies; and (2) a mid to late afternoon onshore sea-breeze related to the peninsula's daily cycle of insolation heating that evolves with counter-clockwise rotation over the Bay of La Paz. The model results reveal the interaction over Baja California of opposing afternoon sea-breeze fronts that originate from the subtropical Pacific Ocean and the Gulf of California, with a convergence line forming over the peaks of the peninsula's topography and the associated presence of a closed vertical circulation cell over the Bay of La Paz and the adjacent Gulf. The collision of the opposing sea-breeze fronts over the narrow peninsula drives convection that is relatively weak due to the reduced heat source and only appears to produce precipitation sporadically. The spatial structure of the sea-breeze fronts over the Bay of La Paz region is complex due to shoreline curvature and nearby topographic features. A comparison of the numerical results with available meteorological near-surface observations indicates that the modelling methodology adequately reproduced the observed features of the seasonal variability of the local planetary boundary-layer diurnal wind cycle and confirms that the low-level atmospheric circulation over the Bay of La Paz is dominated by kinetic energy in the diurnal band

  19. Diurnal temperature range trend over North Carolina and the associated mechanisms

    NASA Astrophysics Data System (ADS)

    Sayemuzzaman, Mohammad; Mekonnen, Ademe; Jha, Manoj K.

    2015-06-01

    This study seeks to investigate the variability and presence of trend in the diurnal surface air temperature range (DTR) over North Carolina (NC) for the period 1950-2009. The significance trend test and the magnitude of trends were determined using the non-parametric Mann-Kendall test and the Theil-Sen approach, respectively. Statewide significant trends (p < 0.05) of decreasing DTR were found in all seasons and annually during the analysis period. Highest (lowest) temporal DTR trends of magnitude - 0.19 (- 0.031) °C/decade were found in summer (winter). Potential mechanisms for the presence/absence of trend in DTR have been highlighted. Historical data sets of the three main moisture components (precipitation, total cloud cover (TCC), and soil moisture) and the two major atmospheric circulation modes (North Atlantic Oscillation and Southern Oscillation) were used for correlation analysis. The DTRs were found to be negatively correlated with the precipitation, TCC and soil moisture across the state for all the seasons and annual basis. It appears that the moisture components related better to the DTR than to the atmospheric circulation modes.

  20. Diurnal pollen tube growth rate is slowed by high temperature in field-grown Gossypium hirsutum pistils.

    PubMed

    Snider, John L; Oosterhuis, Derrick M; Kawakami, Eduardo M

    2011-03-15

    For Gossypium hirsutum pollination, germination, and pollen tube growth must occur in a highly concerted fashion on the day of flowering for fertilization to occur. Because reproductive success could be influenced by the photosynthetic activity of major source leaves, we hypothesized that increased temperatures under field conditions would limit fertilization by inhibiting diurnal pollen tube growth through the style and decreasing subtending leaf photosynthesis. To address this hypothesis, G. hirsutum seeds were sown on different dates to obtain flowers exposed to contrasting ambient temperatures while at the same developmental stage (node 8 above the cotyledons). Collection and measurement were conducted at 06:00, 09:00, 12:00, 15:00, and 18:00h on August 4 (34.6°C maximum air temperature) and 14, 2009 (29.9°C maximum air temperature). Microclimate measurements included photosynthetically active radiation, relative humidity, and air temperature. Pistil measurements included pistil surface temperature, pollen germination, pollen tube growth through the style, fertilization efficiency, fertilized ovule number, and total number of ovules per ovary. Subtending leaf measurements included leaf temperature, photosynthesis, and stomatal conductance. Under high temperatures the first measurable pollen tube growth through the style was observed earlier in the day (12:00h) than under cooler conditions (15:00h). Also, high temperature resulted in slower pollen tube growth through the style (2.05mmh(-1)) relative to cooler conditions (3.35mmh(-1)), but there were no differences in fertilization efficiency, number of fertilized ovules, or ovule number. There was no effect of sampling date on diurnal photosynthetic patterns, where the maximum photosynthetic rate was observed at 12:00h on both dates. It is concluded that, of the measured physiological and reproductive processes, pollen tube growth rate showed the greatest sensitivity to high temperature under field conditions

  1. Land and ocean surface temperature: data development and modeling

    NASA Astrophysics Data System (ADS)

    Zeng, X.; Wang, A.; Brunke, M.

    2014-12-01

    Surface temperature (ST) plays a critical role in land-atmosphere-ocean interactions, and is one of the fundamental variables for Earth system research. ST includes surface air temperature (SAT), surface skin temperature (Ts), and subsurface water or soil temperature at a given depth [T(z)]. In this presentation, we will review our recent work on land and ocean ST. Over land, we have developed the first global 0.5 deg hourly SAT datasets from 1948-2009 by merging in situ CRU data with reanalysis data. Using these datasets, over high latitudes in winter the monthly averaged diurnal temperature range is found to be much larger than the range of monthly averaged hourly temperature diurnal cycle. The former primarily reflects the movement of synoptic weather systems, while the latter is primarily affected by the diurnal radiative forcing. We have also compared Ts from satellite remote sensing (MODIS) and land modeling (CLM) with in situ measurements. For instance, we have identified five factors contributing to the Ts differences between the model and MODIS. Over ocean, we have developed a prognostic Ts parameterization for modeling and data analysis. For instance, the inclusion of the Ts diurnal cycle affects atmospheric processes at diurnal, intraseasonal, and longer time scales. Furthermore, our parameterization provides the relationship between water temperature T(z) at different depths and Ts, and hence helps to merge temperature data from satellite infrared and microwave sensors and in situ buoy and ship measurements.

  2. Diurnal variation of surface ozone in mountainous areas: Case study of Mt. Huang, East China.

    PubMed

    Zhang, Lei; Jin, Lianji; Zhao, Tianliang; Yin, Yan; Zhu, Bin; Shan, Yunpeng; Guo, Xiaomei; Tan, Chenghao; Gao, Jinhui; Wang, Haoliang

    2015-12-15

    To explore the variations in atmospheric environment over mountainous areas, measurements were made from an intensive field observation at the summit of Mt. Huang (30.13°N, 118.15°E, 1841m above sea level), a rural site located in East China, from June to August 2011. The measurements revealed a diurnal change of surface O3 with low concentrations during the daytime and high concentrations during the nighttime. The causes of diurnal O3 variations over the mountain peak in East China were investigated by using a fairly comprehensive WRF-Chem and HYSPLIT4 modeling approach with observational analysis. By varying model inputs and comparing the results to a baseline modeling and actual air quality observations, it is found that nearby ozone urban/anthropogenic emission sources were contributing to a nighttime increase in mountaintop ozone levels due to a regional transport lag and residual layer effects. Positive correlation of measured O3 and CO concentrations suggested that O3 was associated with anthropogenic emissions. Sensitivity modeling experiments indicated that local anthropogenic emissions had little impact on the diurnal pattern of O3. The diurnal pattern of O3 was mainly influenced by regional O3 transport from the surrounding urban areas located 100-150km away from the summit, with a lag time of 10h for transport. PMID:26318811

  3. Climate–vegetation control on the diurnal and seasonal variations of surface urban heat islands in China

    NASA Astrophysics Data System (ADS)

    Zhou, Decheng; Zhang, Liangxia; Li, Dan; Huang, Dian; Zhu, Chao

    2016-07-01

    Remotely sensed surface urban heat islands (UHIs) have gained considerable interest in recent decades due to the easy access and the wall-to-wall coverage of satellite products. The magnitude or intensity of surface UHIs have been well documented at regional and global scales, yet a systematic evaluation of the temporal variability over large areas is still lacking. In this study, the diurnal and seasonal cycles of surface UHI intensities (SUHIIs) in China are examined using Aqua/Terra MODIS data from 2008 to 2012. Results show that the mean annual SUHIIs varied greatly in a diurnal cycle, characterized by a positive day-night difference (DND) in Southeast China and the opposite in Northeast and Northwest China. Also, the SUHIIs differed dramatically in a seasonal cycle, indicated by a positive summer-winter difference (SWD) in the day and a negative SWD at night, accompanied by the highly diverse DNDs across seasons and geographic regions. Northwest and Northeast China overall showed the largest DND and SWD (>3 °C), respectively. These diurnal and seasonal variations depend strongly on local climate-vegetation regimes, as indicated by a strong positive correlation between DND and precipitation (and air temperature) and a negative relationship between DND and vegetation activity across cities and seasons. In particular, SHUIIs were quadratically correlated with the mean annual precipitation across space, suggesting that there might be a threshold in terms of the effects induced by local background climate. Our findings highlight the importance of considering the temporal variability of UHIs for more accurate characterization of the associated ecological and social-economic consequences.

  4. Assessing the Influence of Precipitation on Diurnal Temperature Range Changes: Implications for Climate Change Projection

    NASA Astrophysics Data System (ADS)

    Van den Hoof, C.; Garreaud, R.

    2014-12-01

    . Braganza, D.J. Karoly, and J.M. Arblaster. Diurnal temperature range as an index of global climate change during the twentieth century. Geophysical Research Letters, 31:1-4, 2004. [2] A. Dai, A.D. Del Genio, and I.Y. Fung. Clouds, precipitation and temperature range. Nature, 386:665-666, 1997.

  5. Stimulation of lettuce productivity by manipulation of diurnal temperature and light

    NASA Technical Reports Server (NTRS)

    Knight, Sharon L.; Mitchell, Cary A.

    1983-01-01

    Salad Bowl and Waldmann's Green leaf lettuce (Lactuca sativa L.) were exposed to photosynthetic photon flux densities (PPFDs) of 444 or 889 micromol/s per sq m for 20 hrs/day under a diurnal temperature regime of 25-C days/15-C nights or 20-C days/15-C nights. Leaf dry weight of both cultivars was highest under the high PPFD/warm temperature regime and lowest under the low PPFD/cool temperature regime. Waldmann's Green yielded more than did Salad Bowl at 889 micromol/s per sq m and 25-C days/20-C nights. Under high PPFD, both cultivars yielded better with 25-C days/25-C nights than with 25-C days/20-C nights, although relative growth rates were the same under both temperature regimes.

  6. Physiological and Transcriptional Responses of Anaerobic Chemostat Cultures of Saccharomyces cerevisiae Subjected to Diurnal Temperature Cycles

    PubMed Central

    Hebly, Marit; de Ridder, Dick; de Hulster, Erik A. F.; de la Torre Cortes, Pilar; Pronk, Jack T.

    2014-01-01

    Diurnal temperature cycling is an intrinsic characteristic of many exposed microbial ecosystems. However, its influence on yeast physiology and the yeast transcriptome has not been studied in detail. In this study, 24-h sinusoidal temperature cycles, oscillating between 12°C and 30°C, were imposed on anaerobic, glucose-limited chemostat cultures of Saccharomyces cerevisiae. After three diurnal temperature cycles (DTC), concentrations of glucose and extracellular metabolites as well as CO2 production rates showed regular, reproducible circadian rhythms. DTC also led to waves of transcriptional activation and repression, which involved one-sixth of the yeast genome. A substantial fraction of these DTC-responsive genes appeared to respond primarily to changes in the glucose concentration. Elimination of known glucose-responsive genes revealed an overrepresentation of previously identified temperature-responsive genes as well as genes involved in the cell cycle and de novo purine biosynthesis. In-depth analysis demonstrated that DTC led to a partial synchronization of the cell cycle of the yeast populations in chemostat cultures, which was lost upon release from DTC. Comparison of DTC results with data from steady-state cultures showed that the 24-h DTC was sufficiently slow to allow S. cerevisiae chemostat cultures to acclimate their transcriptome and physiology at the DTC temperature maximum and to approach acclimation at the DTC temperature minimum. Furthermore, this comparison and literature data on growth rate-dependent cell cycle phase distribution indicated that cell cycle synchronization was most likely an effect of imposed fluctuations of the relative growth rate (μ/μmax) rather than a direct effect of temperature. PMID:24814792

  7. Physiological and transcriptional responses of anaerobic chemostat cultures of Saccharomyces cerevisiae subjected to diurnal temperature cycles.

    PubMed

    Hebly, Marit; de Ridder, Dick; de Hulster, Erik A F; de la Torre Cortes, Pilar; Pronk, Jack T; Daran-Lapujade, Pascale

    2014-07-01

    Diurnal temperature cycling is an intrinsic characteristic of many exposed microbial ecosystems. However, its influence on yeast physiology and the yeast transcriptome has not been studied in detail. In this study, 24-h sinusoidal temperature cycles, oscillating between 12°C and 30°C, were imposed on anaerobic, glucose-limited chemostat cultures of Saccharomyces cerevisiae. After three diurnal temperature cycles (DTC), concentrations of glucose and extracellular metabolites as well as CO2 production rates showed regular, reproducible circadian rhythms. DTC also led to waves of transcriptional activation and repression, which involved one-sixth of the yeast genome. A substantial fraction of these DTC-responsive genes appeared to respond primarily to changes in the glucose concentration. Elimination of known glucose-responsive genes revealed an overrepresentation of previously identified temperature-responsive genes as well as genes involved in the cell cycle and de novo purine biosynthesis. In-depth analysis demonstrated that DTC led to a partial synchronization of the cell cycle of the yeast populations in chemostat cultures, which was lost upon release from DTC. Comparison of DTC results with data from steady-state cultures showed that the 24-h DTC was sufficiently slow to allow S. cerevisiae chemostat cultures to acclimate their transcriptome and physiology at the DTC temperature maximum and to approach acclimation at the DTC temperature minimum. Furthermore, this comparison and literature data on growth rate-dependent cell cycle phase distribution indicated that cell cycle synchronization was most likely an effect of imposed fluctuations of the relative growth rate (μ/μmax) rather than a direct effect of temperature. PMID:24814792

  8. Effects of diurnal temperature range on cardiovascular and respiratory hospital admissions in Korea.

    PubMed

    Lim, Youn-Hee; Hong, Yun-Chul; Kim, Ho

    2012-02-15

    The effects of heat and cold waves have been studied as risk factors for cardiovascular and respiratory diseases. However, few studies have examined the effect of diurnal temperature changes on health. We hypothesized that the diurnal temperature range (DTR) may affect the rate of hospital admissions for cardiovascular- and respiratory-related diseases, and therefore investigated the risk of hospital admissions of cardiovascular (stroke, myocardial infarction, ischemic heart disease, cardiac failure, cardiac disease, and arrhythmia) and respiratory (asthma, chronic obstructive pulmonary disease, and pneumonia) diseases attributable to DTR in four metropolitan areas in Korea during 2003-2006. The area-combined effects of DTR on some cardiovascular and respiratory diseases were significantly increased by an increment of DTR. In particular, the effects on cardiac failure and asthma were significant with the percentage change of hospital admissions per 1 °C increment of DTR at 3.0% (95% CI, 1.4-4.6) and 1.1% (95% CI, 0.1-2.0), respectively, among 9 diseases. For those 75 years and older, the DTR effect on asthma admissions was greater than in those aged under 75 years. These results support the hypothesis of a positive association between DTR and cardiovascular and respiratory hospital admission. PMID:22281041

  9. Dating base flow in streams using dissolved gases and diurnal temperature changes

    NASA Astrophysics Data System (ADS)

    Sanford, Ward E.; Casile, Gerolamo; Haase, Karl B.

    2015-12-01

    A method is presented for using dissolved CFCs or SF6 to estimate the apparent age of stream base flow by indirectly estimating the mean concentration of the tracer in the inflowing groundwater. The mean value is estimated simultaneously with the mean residence times of the gas and water in the stream by sampling the stream for one or both age tracers, along with dissolved nitrogen and argon at a single location over a period of approximately 12-14 h. The data are fitted to an equation representing the temporal in-stream gas exchange as it responds to the diurnal temperature fluctuation. The efficacy of the method is demonstrated by collecting and analyzing samples at six different stream locations across parts of northern Virginia, USA. The studied streams drain watersheds with areas of between 2 and 122 km2 during periods when the diurnal stream temperature ranged between 2 and 5°C. The method has the advantage of estimating the mean groundwater residence time of discharge from the watershed to the stream without the need for the collection of groundwater infiltrating to streambeds or local groundwater sampled from shallow observation wells near the stream.

  10. Effects of diurnal temperature range and drought on wheat yield in Spain

    NASA Astrophysics Data System (ADS)

    Hernandez-Barrera, S.; Rodriguez-Puebla, C.; Challinor, A. J.

    2016-04-01

    This study aims to provide new insight on the wheat yield historical response to climate processes throughout Spain by using statistical methods. Our data includes observed wheat yield, pseudo-observations E-OBS for the period 1979 to 2014, and outputs of general circulation models in phase 5 of the Coupled Models Inter-comparison Project (CMIP5) for the period 1901 to 2099. In investigating the relationship between climate and wheat variability, we have applied the approach known as the partial least-square regression, which captures the relevant climate drivers accounting for variations in wheat yield. We found that drought occurring in autumn and spring and the diurnal range of temperature experienced during the winter are major processes to characterize the wheat yield variability in Spain. These observable climate processes are used for an empirical model that is utilized in assessing the wheat yield trends in Spain under different climate conditions. To isolate the trend within the wheat time series, we implemented the adaptive approach known as Ensemble Empirical Mode Decomposition. Wheat yields in the twenty-first century are experiencing a downward trend that we claim is a consequence of widespread drought over the Iberian Peninsula and an increase in the diurnal range of temperature. These results are important to inform about the wheat vulnerability in this region to coming changes and to develop adaptation strategies.

  11. Combined effects of surface conditions, boundary layer dynamics and chemistry on diurnal SOA evolution

    NASA Astrophysics Data System (ADS)

    Janssen, R. H. H.; Vilà-Guerau de Arellano, J.; Ganzeveld, L. N.; Kabat, P.; Jimenez, J. L.; Farmer, D. K.; van Heerwaarden, C. C.; Mammarella, I.

    2012-08-01

    We study the combined effects of land surface conditions, atmospheric boundary layer dynamics and chemistry on the diurnal evolution of biogenic secondary organic aerosol in the atmospheric boundary layer, using a model that contains the essentials of all these components. First, we evaluate the model for a case study in Hyytiälä, Finland, and find that it is able to satisfactorily reproduce the observed dynamics and gas-phase chemistry. We show that the exchange of organic aerosol between the free troposphere and the boundary layer (entrainment) must be taken into account in order to explain the observed diurnal cycle in organic aerosol (OA) concentration. An examination of the budgets of organic aerosol and terpene concentrations show that the former is dominated by entrainment, while the latter is mainly driven by emission and chemical transformation. We systematically investigate the role of the land surface, which governs both the surface energy balance partitioning and terpene emissions, and the large-scale atmospheric process of vertical subsidence. Entrainment is especially important for the dilution of organic aerosol concentrations under conditions of dry soils and low terpene emissions. Subsidence suppresses boundary layer growth while enhancing entrainment. Therefore, it influences the relationship between organic aerosol and terpene concentrations. Our findings indicate that the diurnal evolution of secondary organic aerosols (SOA) in the boundary layer is the result of coupled effects of the land surface, dynamics of the atmospheric boundary layer, chemistry, and free troposphere conditions. This has potentially some consequences for the design of both field campaigns and large-scale modeling studies.

  12. Diurnal and seasonal trends in total gaseous mercury flux from three urban ground surfaces

    NASA Astrophysics Data System (ADS)

    Gabriel, Mark C.; Williamson, Derek G.; Zhang, Hong; Brooks, Steve; Lindberg, Steve

    Total gaseous mercury flux measurements were carried out over three urban ground surfaces for 1 year in Tuscaloosa, AL, USA. The objective was to provide insight into the characteristics of gaseous mercury flux from urban surface covers. Bare soil, grass, and pavement surfaces were sampled as the most representative terrestrial surfaces throughout Tuscaloosa. Measurements were quantified over diurnal and seasonal periods and relationships were developed between flux from each surface and major meteorological parameters. Averaging data over the entire year, fluxes from each surface were as follows: bare soil (6.48 ng/m -2 h), pavement (0.02 ng/m -2 h), and grass (0.28 ng/m -2 h). Pavement and many grass fluxes were small and arguably indistinguishable from chamber blanks. The soil surface displayed the largest difference between evening and daytime flux, particularly during the spring and summer seasons (i.e., evening low (12 ng/m -2 h) to daytime high (30 ng/m -2 h) during summer). The grass surface showed the largest amount of atmospheric deposition, mainly during the spring and fall periods (up to -2.31 ng/m -2 h), with pavement showing somewhat less (up to -1.05 ng/m -2 h). Bare soil showed very little to negligible deposition. Diurnal flux variance was greater than seasonal flux variance for all surfaces. The regression results demonstrate that despite the highly dissimilar physical and geochemical make-up of pavement, bare soil, and grass, each surface displayed similar responses to time series change in meteorological parameters. However, each surface may be seasonally controlled or limited by different sets of meteorological parameters.

  13. Diurnal temperature fluctuation effects on potatoes grown with 12 hr photoperiods

    NASA Technical Reports Server (NTRS)

    Bennett, S. M.; Tibbitts, T. W.; Cao, W.

    1991-01-01

    This study was designed to characterize the growth responses of potato (Solanum tuberosum L.) to diurnal temperature fluctuations. Potato plants of two cultivars, Norland and Denali, were grown for 90 days under 12 hr photoperiod in walk-in growth rooms at the University of Wisconsin Biotron. The alternating temperature was 22 C light/14 C dark and compared to a constant 18 C as control. At all temperature regimes vapor pressure deficit was maintained at 0.62 kPa (70% relative humidity [correction of humdidity] at 18 C). Plant height, plant dry weight, tuber dry weight, and harvest index were overall greater under the warm light/cool dark alternating temperatures than under the constant temperature. The differences between temperature treatments were greater for Denali than for Norland. Alternating temperatures increased Denali tuber weights by 25%, but no significant increase was found with Norland. Also the total plant weight was increased over 20% with Denali, but increased with Norland in only one of the two replications of the experiment. This study documents that alternating temperatures are a benefit to some cultivars but may not be of benefit to all cultivars.

  14. HCMM detection of high soil moisture areas. [by diurnal temperature observation

    NASA Technical Reports Server (NTRS)

    Heilman, J. L.; Moore, D. G.

    1981-01-01

    It is noted that one objective of NASA's Heat Capacity Mapping Mission (HCMM) is to evaluate the feasibility of using HCMM data to assess soil moisture effects by observing temperatures near the maximum and minimum of the diurnal temperature cycle. The satellite, which carries a two-channel radiometer (0.5-1.1 and 10.5-12.5 microns) gathers data at 1:30 P.M. and 2:30 A.M. local time at midlatitudes, with a repeat cycle of 5 or 16 days depending on latitude. The spatial resolutions are 0.5 x 0.5 km at nadir for the visible channel and 0.6 x 0.6 km at nadir for the thermal infrared channel. An example is presented here of HCMM detection of a region of high soil moisture.

  15. Horizontal Heat Impact of Urban Structures on the Surface Soil Layer and Its Diurnal Patterns under Different Micrometeorological Conditions

    NASA Astrophysics Data System (ADS)

    Zhou, Hongxuan; Hu, Dan; Wang, Xiaolin; Han, Fengsen; Li, Yuanzheng; Wu, Xiaogang; Ma, Shengli

    2016-01-01

    The temperature of the surface soil layer around different orientation walls was investigated horizontally along several construction-soil micro-gradients in Beijing, China. On a diurnal scale, similar fluctuating trends in T0 and T50 (temperature of surface soil layer, 0 and 0.5 m from the building baseline) adjacent to the external walls of buildings with the same orientation usually appeared under similar micrometeorological conditions. The difference between T0 and T50 (ΔT0-50) can be considered an indicator of the intensity of the horizontal heat effects: higher ΔT0-50 values correspond to greater intensities. The values of ΔT0-50 for south-, north-, east- and west-facing sides of buildings were highest on sunny days in summer and exhibited values of 6.61 K, 1.64 K, 5.93 K and 2.76 K, respectively. The scope of horizontal heat impacts (Sh) changed on a diurnal scale between zero and the maximum, which fluctuated with the micrometeorological conditions. The maximum values of Sh were 0.30, 0.15, 0.20 and 0.20 m for south-, north-, east-, and west-facing walls. The ΔT0-50 was related to solar radiation, horizontal heat flux, relative humidity, wind speed, soil moisture differences and air temperature; the relative importance of these factors was 36.22%, 31.80%, 19.19%, 2.67%, 3.68% and 6.44%, respectively.

  16. Horizontal Heat Impact of Urban Structures on the Surface Soil Layer and Its Diurnal Patterns under Different Micrometeorological Conditions.

    PubMed

    Zhou, Hongxuan; Hu, Dan; Wang, Xiaolin; Han, Fengsen; Li, Yuanzheng; Wu, Xiaogang; Ma, Shengli

    2016-01-01

    The temperature of the surface soil layer around different orientation walls was investigated horizontally along several construction-soil micro-gradients in Beijing, China. On a diurnal scale, similar fluctuating trends in T0 and T50 (temperature of surface soil layer, 0 and 0.5 m from the building baseline) adjacent to the external walls of buildings with the same orientation usually appeared under similar micrometeorological conditions. The difference between T0 and T50 (ΔT 0-50) can be considered an indicator of the intensity of the horizontal heat effects: higher ΔT 0-50 values correspond to greater intensities. The values of ΔT 0-50 for south-, north-, east- and west-facing sides of buildings were highest on sunny days in summer and exhibited values of 6.61 K, 1.64 K, 5.93 K and 2.76 K, respectively. The scope of horizontal heat impacts (Sh) changed on a diurnal scale between zero and the maximum, which fluctuated with the micrometeorological conditions. The maximum values of Sh were 0.30, 0.15, 0.20 and 0.20 m for south-, north-, east-, and west-facing walls. The ΔT 0-50 was related to solar radiation, horizontal heat flux, relative humidity, wind speed, soil moisture differences and air temperature; the relative importance of these factors was 36.22%, 31.80%, 19.19%, 2.67%, 3.68% and 6.44%, respectively. PMID:26728627

  17. Horizontal Heat Impact of Urban Structures on the Surface Soil Layer and Its Diurnal Patterns under Different Micrometeorological Conditions

    PubMed Central

    Zhou, Hongxuan; Hu, Dan; Wang, Xiaolin; Han, Fengsen; Li, Yuanzheng; Wu, Xiaogang; Ma, Shengli

    2016-01-01

    The temperature of the surface soil layer around different orientation walls was investigated horizontally along several construction-soil micro-gradients in Beijing, China. On a diurnal scale, similar fluctuating trends in T0 and T50 (temperature of surface soil layer, 0 and 0.5 m from the building baseline) adjacent to the external walls of buildings with the same orientation usually appeared under similar micrometeorological conditions. The difference between T0 and T50 (ΔT0–50) can be considered an indicator of the intensity of the horizontal heat effects: higher ΔT0–50 values correspond to greater intensities. The values of ΔT0–50 for south-, north-, east- and west-facing sides of buildings were highest on sunny days in summer and exhibited values of 6.61 K, 1.64 K, 5.93 K and 2.76 K, respectively. The scope of horizontal heat impacts (Sh) changed on a diurnal scale between zero and the maximum, which fluctuated with the micrometeorological conditions. The maximum values of Sh were 0.30, 0.15, 0.20 and 0.20 m for south-, north-, east-, and west-facing walls. The ΔT0–50 was related to solar radiation, horizontal heat flux, relative humidity, wind speed, soil moisture differences and air temperature; the relative importance of these factors was 36.22%, 31.80%, 19.19%, 2.67%, 3.68% and 6.44%, respectively. PMID:26728627

  18. The influence of diurnal temperature range on the incidence of respiratory syncytial virus in Japan.

    PubMed

    Onozuka, D

    2015-03-01

    The incidence of respiratory syncytial virus (RSV) has been reported to exhibit seasonal variation. However, the impact of diurnal temperature range (DTR) on RSV has not been investigated. After acquiring data related to cases of RSV and weather parameters of DTR in Fukuoka, Japan, between 2006 and 2012, we used negative binomial generalized linear models and distributed lag nonlinear models to assess the possible relationship between DTR and RSV cases, adjusting for confounding factors. Our analysis revealed that the weekly number of RSV cases increased with a relative risk of 3·30 (95% confidence interval 1·65-6·60) for every 1°C increase in DTR. Our study provides quantitative evidence that the number of RSV cases increased significantly with increasing DTR. We suggest that preventive measures for limiting the spread of RSV should be considered during extended periods of high DTR. PMID:25092407

  19. LAND SURFACE TEMPERATURE RETRIEVAL AT HIGH SPATIAL AND TEMPORAL RESOLUTIONS OVER THE SOUTHWESTERN UNITED STATES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature (LST) and its diurnal variation are important observable characteristics when evaluating climate change, land-atmosphere energy exchange processes and the global hydrological cycle. These characteristics are observable from satellite platforms using thermal infrared, but do...

  20. Global surface temperatures and the atmospheric electrical circuit

    NASA Technical Reports Server (NTRS)

    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. Effect of diurnal temperature range on cardiovascular markers in the elderly in Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Lim, Youn-Hee; Kim, Ho; Kim, Jin Hee; Bae, Sanghyuk; Hong, Yun-Chul

    2013-07-01

    While diurnal temperature range (DTR) has been found to be a risk factor for mortality, evaluation of the underlying mechanisms involved in this association are lacking. To explain the association between DTR and health effects, we investigated how cardiovascular markers responded to DTR. Data was obtained from 560 participants who regularly attended a community elderly welfare center located in Seoul, Korea. Data collection was conducted a total of five times over a 3-year period beginning in August, 2008. We examined systolic and diastolic blood pressure (BP), heart rate (HR), and heart rate variability (HRV). Mixed-effects models and generalized additive mixed models were used to assess the relationship of DTR with BP, HR, and HRV. BP was not associated significantly with rapid temperature changes during the day. While HR was associated linearly with increments of DTR, the relationship between DTR and HRV showed nonlinear associations, or the presence of a cutoff around median DTR. At the cutoff level of DTR determined by an inflection point in the graph, standard deviation of normal-to-normal intervals (SDNN) and root mean square successive difference (RMSSD) were peaked, whereas the low frequency:high frequency (LF:HF) ratio was elevated with decreasing DTR below the cutoff level. The study demonstrated that HR increases with increasing temperature range during the day, and that HRV is reduced at small or large DTR, which suggests minimal cardiovascular stress around the median level of temperature range during the day.

  2. Diurnal temperature range and emergency room admissions for chronic obstructive pulmonary disease in Taiwan

    NASA Astrophysics Data System (ADS)

    Liang, Wen-Miin; Liu, Wen-Pin; Kuo, Hsien-Wen

    2009-01-01

    The objective of this study was to assess the relationship between diurnal temperature range (DTR) and emergency room (ER) admissions for chronic obstructive pulmonary disease (COPD) in an ER in Taichung City, Taiwan. The design was a longitudinal study in which DTR was related to COPD admissions to the ER of the city’s largest hospital. Daily ER admissions for COPD and ambient temperature were collected from 1 January 2001 to 31 December 2002. There was a significant negative association between the average daily temperature and ER admissions for COPD ( r = -0.95). However, a significant positive association between DTR and COPD admissions was found ( r = 0.90). Using the Poisson regression model after adjusting for the effects of air pollutants and the day of the week, COPD admissions to the ER increased by 14% when DTR was over 9.6°C. COPD patients must be made aware of the increased risk posed by large DTR. Hospitals and ERs should take into account the increased demand of specific facilities during periods of large temperature variations.

  3. Modifiers of diurnal temperature range and mortality association in six Korean cities

    NASA Astrophysics Data System (ADS)

    Lim, Youn-Hee; Park, Ae Kyung; Kim, Ho

    2012-01-01

    Rapid temperature changes within a single day may be critical for populations vulnerable to thermal stress who have difficulty adjusting themselves behaviorally and physiologically. We hypothesized that diurnal temperature range (DTR) is associated with mortality, and that this association is modified by season and socioeconomic status (SES). We evaluated meteorological and mortality data from six metropolitan areas in Korea from 1992 to 2007. We applied generalized linear models (GLM) for quantifying the estimated effects of DTR on mortality after adjusting for mean temperature, dew point temperature, day of the week, and seasonal and long-term trends. Most areas showed a linear DTR-mortality relationship, with evidence of increasing mortality with increasing DTR. Deaths among the elderly (75 years or older), females, the less educated, and the non-hospital population were associated more strongly with DTR than with the corresponding categories. DTR was the greatest threat to vulnerable study populations, with greater influence in the fall season. DTR was found to be a predictor of mortality, and this relationship was modified by season and SES.

  4. Average diurnal behavior of surface winds during summer at sites in complex terrain

    SciTech Connect

    Garrett, A.J.; Smith, F.G. III

    1985-02-01

    Mean diurnal wind distributions from five surface stations in the rugged Geysers area of northern California were examined to determine how they were affected by the terrain. The one-dimensional slop-flow model of Garrett was abel to simulate the average diurnal wind distribution at the station with the simplest slope geometry and using only routine weather observations as input. Wind direction frequency distributions at the other four stations clearly could not be explained by a simple daytime upslope and nighttime downslope wind distribution. Winds blew perpendicular to canyon axes (simple katabatic and daytime upslope flow) or parallel to canyon axes (organized drainage and upvalley winds), depending on station location. Winds always blew upslope during the day, but at two stations the wind blen some night and downslope on the others. The upslope flow at night may have been caused by prevailing winds in one case, and by drainage winds flowing off an opposing slope and across the intervening riverbed in the other.

  5. Partitioning evapotranspiration using diurnal surface temperature variation 1861

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The encroachment of woody plants in grasslands across the Western U.S. will affect soil water availability by altering the contributions of evaporation (E) and transpiration (T) to total evapotranspiration (ET). To study this phenomenon, a network of flux stations is in place to measure ET in grass...

  6. Seasonal Changes in Surface Temperatures on Titan

    NASA Technical Reports Server (NTRS)

    Jennings, D. E.; Cottini, V.; Nixon, C. A.

    2010-01-01

    The surface brightness temperatures on Titan have been measured by the Composite Infrared Spectrometer (CIRS) aboard Cassini during the period spanning late northern winter through vernal equinox. CIRS observes radiance from the surface through a spectral window at 19 microns where the atmosphere has an opacity minimum [I]. CIRS is now seeing a shift in the latitudinal distribution of temperatures froth a distinctly warmer south to a more symmetrical north -south pattern, similar to that found by Voyager IRIS [2,3] at the time of the previous vernal equinox. Near the equator the temperatures remain close to the 93.7 K value found at the surface by Huygens [4]. From the equator to the poles the temperature gradients are 2-3 K. When compared with predictions froth general circulation models [5] the measured temperatures and their seasonal changes constrain the possible types of surface material. As Cassini continues through Titan's northern spring CiRS will extend its, global coverage to took for correlations between surface temperatures and albedo and to search for diurnal temperature variations

  7. Climate Implications of the Moist-convective Diurnal Cycle

    NASA Astrophysics Data System (ADS)

    Ruppert, James

    2016-04-01

    This idealized modeling study is provoked by recent observations from the tropical Indian Ocean (the DYNAMO field campaign), which demonstrate the high degree to which column humidity is modulated by the diurnal cycle of clouds. Under suppressed large-scale conditions, shallow convection prevails, and the diurnal cycles of shortwave radiative heating and sea surface temperature (SST) are at their strongest. In turn, the diurnal cycle of clouds is prominent, which is manifest in daytime cloud deepening and tropospheric moistening in response to boundary layer warming (bearing resemblance to the diurnal cycle over land). An idealized modeling study is performed to 1) assess the driving processes in the diurnal cycle (i.e., SST vs. radiative forcing) and 2) assess whether or not this diurnal cycle rectifies onto longer timescales. A cloud-resolving model framework is employed with the CM1 model (Bryan and Fritsch 2002), wherein a diurnal cycle of SST is prescribed, fully-interactive radiation varies diurnally, and the weak temperature gradient (WTG) approximation is invoked to simulate the feedbacks between the moist convection and large-scale circulation. The results suggest that the diurnal cycle is highly nonlinear, in that the diurnal fluctuation of clouds strongly rectifies onto longer timescales. The diurnal cycle must therefore be regarded as a "forcing mechanism" to the climate system. The vitality and quality of the moist-convective diurnal cycle in climate models may in turn be important to the accuracy of their simulations.

  8. The diurnal course of soil moisture as measured by various dielectric sensors: Effects of soil temperature and the implications for evaporation estimates

    NASA Astrophysics Data System (ADS)

    Verhoef, A.; Fernández-Gálvez, J.; Diaz-Espejo, A.; Main, B. E.; El-Bishti, M.

    2006-04-01

    Soil moisture content, θ, of a bare and vegetated UK gravelly sandy loam soil (in situ and repacked in small lysimeters) was measured using various dielectric instruments (single-sensor ThetaProbes, multi-sensor Profile Probes, and Aquaflex Sensors), at depths ranging between 0.03 and 1 m, during the summers of 2001 (in situ soil) and 2002 (mini-lysimeters). Half-hourly values of evaporation, E, were calculated from diurnal changes in total soil profile water content, using the soil water balance equation. For the bare soil field, Profile Probes and ML2x ThetaProbes indicated a diurnal course of θ that did not concur with typical soil physical observations: surface layer soil moisture content increased from early morning until about midday, after which θ declined, generally until the early evening. The unexpected course of θ was positively correlated to soil temperature, Ts, also at deeper depths. Aquaflex and ML1 ThetaProbe (older models) outputs, however, reflected common observations: θ increased slightly during the night (capillary rise) and decreased from the morning until late afternoon (as a result of evaporation). For the vegetated plot, the spurious diurnal θ fluctuations were less obvious, because canopy shading resulted in lower amplitudes of Ts. The unrealistic θ profiles measured for the bare and vegetated field sites caused diurnal estimates of E to attain downward daytime and upward night-time values. In the mini-lysimeters, at medium to high moisture contents, θ values measured by (ML2x) ThetaProbes followed a relatively realistic course, and predictions of E from diurnal changes in vertically integrated θ generally compared well with lysimeter estimates of E. However, time courses of θ and E became comparable to those observed for the field plots when the soil in the lysimeters reached relatively low values of θ. Attempts to correct measured θ for fluctuations in Ts revealed that no generally applicable formula could be derived.

  9. EFFECTS OF MODERATELY HIGH TEMPERATURE ON DIURNAL POLLEN TUBE GROWTH AND FERTILIZATION IN FIELD-GROWN COTTON

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For Gossypium hirsutum pollination, germination, and pollen tube growth must occur in a highly concerted fashion on the day of flowering for fertilization to occur. We hypothesized that increased temperatures under field conditions would limit fertilization by inhibiting diurnal pollen tube growth t...

  10. Impact of diurnal temperature range on human health: a systematic review

    NASA Astrophysics Data System (ADS)

    Cheng, Jian; Xu, Zhiwei; Zhu, Rui; Wang, Xu; Jin, Liu; Song, Jian; Su, Hong

    2014-02-01

    Increasing epidemiological studies have shown that a rapid temperature change within 1 day is an independent risk factor for human health. This paper aimed to systematically review the epidemiological evidence on the relationship between diurnal temperature range (DTR) and human health and to propose future research directions. A literature search was conducted in October 2013 using the databases including PubMed, ScienceDirect, and EBSCO. Empirical studies regarding the relationship between DTR and mortality and morbidity were included. Twenty-five relevant studies were identified, among which, 11 investigated the relationship between DTR and mortality and 14 examined the impact of DTR on morbidity. The majority of existing studies reported that DTR was significantly associated with mortality and morbidity, particularly for cardiovascular and respiratory diseases. Notably, compared with adults, the elderly and children were more vulnerable to DTR effects. However, there were some inconsistencies regarding the susceptible groups, lag time, and threshold of DTR. The impact of DTR on human health may be confounded or modified by season, socioeconomic, and educational status. Further research is needed to further confirm the adverse effects of DTR in different geographical locations; examine the effects of DTR on the health of children aged one or under; explore extreme DTR effects on human health; analyze the difference of DTR effects on human health in different locations and the modified effects of potential confounding factors; and develop detailed preventive measures against large DTR, particularly for susceptible groups.

  11. Impact of diurnal temperature range on human health: a systematic review.

    PubMed

    Cheng, Jian; Xu, Zhiwei; Zhu, Rui; Wang, Xu; Jin, Liu; Song, Jian; Su, Hong

    2014-11-01

    Increasing epidemiological studies have shown that a rapid temperature change within 1 day is an independent risk factor for human health. This paper aimed to systematically review the epidemiological evidence on the relationship between diurnal temperature range (DTR) and human health and to propose future research directions. A literature search was conducted in October 2013 using the databases including PubMed, ScienceDirect, and EBSCO. Empirical studies regarding the relationship between DTR and mortality and morbidity were included. Twenty-five relevant studies were identified, among which, 11 investigated the relationship between DTR and mortality and 14 examined the impact of DTR on morbidity. The majority of existing studies reported that DTR was significantly associated with mortality and morbidity, particularly for cardiovascular and respiratory diseases. Notably, compared with adults, the elderly and children were more vulnerable to DTR effects. However, there were some inconsistencies regarding the susceptible groups, lag time, and threshold of DTR. The impact of DTR on human health may be confounded or modified by season, socioeconomic, and educational status. Further research is needed to further confirm the adverse effects of DTR in different geographical locations; examine the effects of DTR on the health of children aged one or under; explore extreme DTR effects on human health; analyze the difference of DTR effects on human health in different locations and the modified effects of potential confounding factors; and develop detailed preventive measures against large DTR, particularly for susceptible groups. PMID:24535132

  12. Surface Temperature Data Analysis

    NASA Technical Reports Server (NTRS)

    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.

  13. Diurnal and vertical variability of the sensible heat and carbon dioxide budgets in the atmospheric surface layer

    USGS Publications Warehouse

    Casso-Torralba, P.; de Arellano, J. V. -G.; Bosveld, F.; Soler, M.R.; Vermeulen, A.; Werner, C.; Moors, E.

    2008-01-01

    The diurnal and vertical variability of heat and carbon dioxide (CO2) in the atmospheric surface layer are studied by analyzing measurements from a 213 in tower in Cabauw (Netherlands). Observations of thermodynamic variables and CO2 mixing ratio as well as vertical profiles of the turbulent fluxes are used to retrieve the contribution of the budget terms in the scalar conservation equation. On the basis of the daytime evolution of turbulent fluxes, we calculate the budget terms by assuming that turbulent fluxes follow a linear profile with height. This assumption is carefully tested and the deviation ftom linearity is quantified. The budget calculation allows us to assess the importance of advection of heat and CO2 during day hours for three selected days. It is found that, under nonadvective conditions, the diurnal variability of temperature and CO2 is well reproduced from the flux divergence measurements. Consequently, the vertical transport due to the turbulent flux plays a major role in the daytime evolution of both scalars and the advection is a relatively small contribution. During the analyzed days with a strong contribution of advection of either heat or carbon dioxide, the flux divergence is still an important contribution to the budget. For heat, the quantification of the advection contribution is in close agreement with results from a numerical model. For carbon dioxide, we qualitatively corroborate the results with a Lagrangian transport model. Our estimation of advection is compared with, traditional estimations based on the Net Ecosystem-atmosphere Exchange (NEE). Copyright 2008 by the American Geophysical Union.

  14. Diurnal temperature range and short-term mortality in large US communities

    NASA Astrophysics Data System (ADS)

    Lim, Youn-Hee; Reid, Colleen E.; Mann, Jennifer K.; Jerrett, Michael; Kim, Ho

    2015-09-01

    Research has shown that diurnal temperature range (DTR) is significantly associated with mortality and morbidity in regions of Asia; however, few studies have been conducted in other regions such as North America. Thus, we examined DTR effects on mortality in the USA. We used mortality and environmental data from the National Morbidity Mortality Air Pollution Study (NMMAPS). The data are daily mortality, air pollution, and temperature statistics from 95 large US communities collected between 1987 and 2000. To assess community-specific DTR effects on mortality, we used Poisson generalized linear models allowing for over-dispersion. After assessing community-specific DTR effects on mortality, we estimated region- and age-specific effects of DTR using two-level normal independent sampling estimation. We found a significant increase of 0.27 % [95 % confidence intervals (CI), 0.24-0.30 %] in nonaccidental mortality across 95 communities in the USA associated with a 1 °C increase in DTR, controlling for apparent temperature, day of the week, and time trend. This overall effect was driven mainly by effects of DTR on cardiovascular and respiratory mortality in the elderly: Mortality in the above 65 age group increased by 0.39 % (95 % CI, 0.33-0.44 %) and 0.33 % (95 % CI, 0.22-0.44 %), respectively. We found some evidence of regional differences in the effects of DTR on nonaccidental mortality with the highest effects in Southern California [0.31 % (95 % CI, 0.21-0.42 %)] and smallest effects in the Northwest and Upper Midwest regions [0.22 % (95 % CI, 0.11-0.33 %) and 0.22 % (95 % CI, 0.07-0.37 %), respectively]. These results indicate a statistically significant association between DTR and mortality on average for 95 large US communities. The findings indicate that DTR impacts on nonaccidental and cardiovascular-related mortality in most US regions and the elderly population was most vulnerable to the effects of DTR.

  15. Field study and simulation of diurnal temperature effects on infiltration and variably saturated flow beneath an ephemeral stream

    USGS Publications Warehouse

    Ronan, A.D.; Prudic, D.E.; Thodal, C.E.; Constantz, J.

    1998-01-01

    Two experiments were performed to investigate flow beneath an ephemeral stream and to estimate streambed infiltration rates. Discharge and stream-area measurements were used to determine infiltration rates. Stream and subsurface temperatures were used to interpret subsurface flow through variably saturated sediments beneath the stream. Spatial variations in subsurface temperatures suggest that flow beneath the streambed is dependent on the orientation of the stream in the canyon and the layering of the sediments. Streamflow and infiltration rates vary diurnally: Stream flow is lowest in late afternoon when stream temperature is greatest and highest in early morning when stream temperature is least. The lower afternoon streamflow is attributed to increased infiltration rates; evapotranspiration is insufficient to account for the decreased streamflow. The increased infiltration rates are attributed to viscosity effects on hydraulic conductivity from increased stream temperatures. The first set of field data was used to calibrate a two-dimensional variably saturated flow model that includes heat transport. The model was calibrated to (1) temperature fluctuations in the subsurface and (2) infiltration rates determined from measured stream flow losses. The second set of field data was to evaluate the ability to predict infiltration rates on the basis of temperature measurements alone. Results indicate that the variably saturated subsurface flow depends on downcanyon layering of the sediments. They also support the field observations in indicating that diurnal changes in infiltration can be explained by temperature dependence of hydraulic conductivity. Over the range of temperatures and flows monitored, diurnal stream temperature changes can be used to estimate streambed infiltration rates. It is often impractical to maintain equipment for determining infiltration rates by traditional means; however, once a model is calibrated using both infiltration and temperature data

  16. Variability and trends in daily minimum and maximum temperatures and in the diurnal temperature range in Lithuania, Latvia and Estonia in 1951-2010

    NASA Astrophysics Data System (ADS)

    Jaagus, Jaak; Briede, Agrita; Rimkus, Egidijus; Remm, Kalle

    2014-10-01

    Spatial distribution and trends in mean and absolute maximum and minimum temperatures and in the diurnal temperature range were analysed at 47 stations in the eastern Baltic region (Lithuania, Latvia and Estonia) during 1951-2010. Dependence of the studied variables on geographical factors (latitude, the Baltic Sea, land elevation) is discussed. Statistically significant increasing trends in maximum and minimum temperatures were detected for March, April, July, August and annual values. At the majority of stations, the increase was detected also in February and May in case of maximum temperature and in January and May in case of minimum temperature. Warming was slightly higher in the northern part of the study area, i.e. in Estonia. Trends in the diurnal temperature range differ seasonally. The highest increasing trend revealed in April and, at some stations, also in May, July and August. Negative and mostly insignificant changes have occurred in January, February, March and June. The annual temperature range has not changed.

  17. Reassessing changes in diurnal temperature range: Intercomparison and evaluation of existing global data set estimates

    NASA Astrophysics Data System (ADS)

    Thorne, P. W.; Donat, M. G.; Dunn, R. J. H.; Williams, C. N.; Alexander, L. V.; Caesar, J.; Durre, I.; Harris, I.; Hausfather, Z.; Jones, P. D.; Menne, M. J.; Rohde, R.; Vose, R. S.; Davy, R.; Klein-Tank, A. M. G.; Lawrimore, J. H.; Peterson, T. C.; Rennie, J. J.

    2016-05-01

    Changes in diurnal temperature range (DTR) over global land areas are compared from a broad range of independent data sets. All data sets agree that global-mean DTR has decreased significantly since 1950, with most of that decrease occurring over 1960-1980. The since-1979 trends are not significant, with inter-data set disagreement even over the sign of global changes. Inter-data set spread becomes greater regionally and in particular at the grid box level. Despite this, there is general agreement that DTR decreased in North America, Europe, and Australia since 1951, with this decrease being partially reversed over Australia and Europe since the early 1980s. There is substantive disagreement between data sets prior to the middle of the twentieth century, particularly over Europe, which precludes making any meaningful conclusions about DTR changes prior to 1950, either globally or regionally. Several variants that undertake a broad range of approaches to postprocessing steps of gridding and interpolation were analyzed for two of the data sets. These choices have a substantial influence in data sparse regions or periods. The potential of further insights is therefore inextricably linked with the efficacy of data rescue and digitization for maximum and minimum temperature series prior to 1950 everywhere and in data sparse regions throughout the period of record. Over North America, station selection and homogeneity assessment is the primary determinant. Over Europe, where the basic station data are similar, the postprocessing choices are dominant. We assess that globally averaged DTR has decreased since the middle twentieth century but that this decrease has not been linear.

  18. Retrieval of the bulk density of lunar subsurface layer from diurnal differences of Chang‧E-2 microwave and LRO infrared brightness temperature data

    NASA Astrophysics Data System (ADS)

    Zhang, Dan; Li, Qingxia; Lang, Liang; Xiao, Qunhua; Zheng, Yongchun

    2015-08-01

    Comparisons of microwave brightness temperature (TB) observed by Chang‧E-1 and Chang‧E-2 with FeO + TiO2 content observed by Clementine indicate a correspondence of diurnal difference of microwave TB to FeO + TiO2 content in distribution, especially for 37 GHz. The correlation of FeO + TiO2 content and 37 GHz TB is discussed. Consequently, we choose the regions, e.g. (30°N, 25°W) in Mare Imbrium and (30°N, 55°W) in Oceanus Procellarum of uniform FeO + TiO2 content for further studying the bulk density of lunar subsurface layer, avoiding the interference of FeO and TiO2. The lunar surface is regarded as a two-layer model. According to the infrared TB observed by LRO which is approximately equal to lunar surface temperature, it is found that the thermophysical properties of the lunar upper surface layer appear uniform for the sampled regions. In that way, distinct diurnal differences of microwave TB in both regions are related to the bulk density of lunar subsurface layer. A theoretical analysis based on a two-layer microwave TB model confirms the correlation between diurnal differences of microwave TB and bulk density of lunar subsurface layer. Finally, the bulk density of lunar subsurface layer is retrieved from microwave TB observed by Chang‧E-2, ranging from 1.90 to 2.04 g/cm3 for a profile at 33°N extending from 120°W to 6°E.

  19. Comprehensive approach to understand the association between diurnal temperature range and mortality in East Asia.

    PubMed

    Kim, Jayeun; Shin, Jihye; Lim, Youn-Hee; Honda, Yasushi; Hashizume, Masahiro; Guo, Yue Leon; Kan, Haidong; Yi, Seungmuk; Kim, Ho

    2016-01-01

    An adverse association between diurnal temperature range (DTR) and mortality has been suggested, but with variable relationships in different cities. Comprehensive approaches to understanding the health effects of DTR using multinational data are required. We investigated the association between DTR and cause-specific mortality in an age-specific population and assessed the dependency of the health effects of DTR on geographic and climatic factors. Poisson generalized linear regression analyses with allowances for over-dispersion were applied to daily DTR and cause-specific mortality data from 30 cities in China, Japan, Korea, and Taiwan between 1979 and 2010, adjusted for various climatic and environmental factors. City-specific effects of DTR were estimated and summarized for the overall effects using geographic and climatic determinants in a meta-analysis. For all-cause, circulatory, and respiratory mortality, the greatest city-specific effects per 1°C DTR were found in Tianjin, China (1.80%; 95% confidence interval [CI]: 0.48, 3.14); Tangshan, China (2.25%; 95% CI: 0.65, 3.87); and Incheon, Korea (2.84%; 95% CI: 0.04, 5.73), respectively, and overall effects across 30 cities were 0.58% (95% CI: 0.44, 0.72), 0.81% (95% CI: 0.60, 1.03), and 0.90% (95% CI: 0.63, 1.18), respectively. Using quartile cutoff values for climatic (DTR, and mean temperature) and geographic (latitude, and longitude) characteristics, we divided the 30 cities into 4 different groups and conducted a meta-analysis within the groups using either a random or fixed effects model. Adverse effects of DTR were more pronounced for those aged ≥65years and varied according to geographic, longitudinal (0.07%; 95% CI: 0.05, 0.10), and climatic characteristics and the scale of DTR (0.33%; 95% CI: 0.12, 0.55) for overall all-cause mortality. The DTR is a risk factor affecting human health, depending on geographic location and the temperature variation, with particular vulnerability in aged populations

  20. Diurnally Varying Hydrogen Volatiles or Regolith Temperature? Mare and Highlands Studies of the Moon's Diurnally Modulating Epithermal Neutron Flux Using LRO's LEND, Diviner, and LOLA Instruments

    NASA Astrophysics Data System (ADS)

    McClanahan, T. P.; LEND Team; Parsons, A. M.; Williams, J. P.; Mazarico, E.

    2015-10-01

    In this study we seek to discriminate the source of variation that is diurnally modulating the Moon's neutron emission flux. We characterize the neutron emission flux from the topography in the northern mare and highlands regions.

  1. Amplitude of the diurnal temperature cycle as observed by thermal infrared and microwave radiometers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature (LST) is a key input to physically-based retrieval algorithms of hydrological states and fluxes, and global measurements of LST are provided by many satellite platforms. Passive microwave (MW) observations offer an alternative to conventional thermal infrared (TIR) LST retri...

  2. Reduced diurnal temperature range does not change warming impacts on ecosystem carbon balance of Mediterranean grassland mesocosms

    DOE PAGESBeta

    Phillips, Claire L.; Gregg, Jillian W.; Wilson, John K.

    2011-11-01

    Daily minimum temperature (Tmin) has increased faster than daily maximum temperature (Tmax) in many parts of the world, leading to decreases in diurnal temperature range (DTR). Projections suggest these trends are likely to continue in many regions, particularly northern latitudes and in arid regions. Despite wide speculation that asymmetric warming has different impacts on plant and ecosystem production than equal-night-and-day warming, there has been little direct comparison of these scenarios. Reduced DTR has also been widely misinterpreted as a result of night-only warming, when in fact Tmin occurs near dawn, indicating higher morning as well as night temperatures. We reportmore » on the first experiment to examine ecosystem-scale impacts of faster increases in Tmin than Tmax, using precise temperature controls to create realistic diurnal temperature profiles with gradual day-night temperature transitions and elevated early morning as well as night temperatures. Studying a constructed grassland ecosystem containing species native to Oregon, USA, we found the ecosystem lost more carbon at elevated than ambient temperatures, but was unaffected by the 3ºC difference in DTR between symmetric warming (constantly ambient +3.5ºC) and asymmetric warming (dawn Tmin=ambient +5ºC, afternoon Tmax= ambient +2ºC). Reducing DTR had no apparent effect on photosynthesis, likely because temperatures were most different in the morning and late afternoon when light was low. Respiration was also similar in both warming treatments, because respiration temperature sensitivity was not sufficient to respond to the limited temperature differences between asymmetric and symmetric warming. We concluded that changes in daily mean temperatures, rather than changes in Tmin/Tmax, were sufficient for predicting ecosystem carbon fluxes in this reconstructed Mediterranean grassland system.« less

  3. Reduced diurnal temperature range does not change warming impacts on ecosystem carbon balance of Mediterranean grassland mesocosms

    SciTech Connect

    Phillips, Claire L.; Gregg, Jillian W.; Wilson, John K.

    2011-11-01

    Daily minimum temperature (Tmin) has increased faster than daily maximum temperature (Tmax) in many parts of the world, leading to decreases in diurnal temperature range (DTR). Projections suggest these trends are likely to continue in many regions, particularly northern latitudes and in arid regions. Despite wide speculation that asymmetric warming has different impacts on plant and ecosystem production than equal-night-and-day warming, there has been little direct comparison of these scenarios. Reduced DTR has also been widely misinterpreted as a result of night-only warming, when in fact Tmin occurs near dawn, indicating higher morning as well as night temperatures. We report on the first experiment to examine ecosystem-scale impacts of faster increases in Tmin than Tmax, using precise temperature controls to create realistic diurnal temperature profiles with gradual day-night temperature transitions and elevated early morning as well as night temperatures. Studying a constructed grassland ecosystem containing species native to Oregon, USA, we found the ecosystem lost more carbon at elevated than ambient temperatures, but was unaffected by the 3ºC difference in DTR between symmetric warming (constantly ambient +3.5ºC) and asymmetric warming (dawn Tmin=ambient +5ºC, afternoon Tmax= ambient +2ºC). Reducing DTR had no apparent effect on photosynthesis, likely because temperatures were most different in the morning and late afternoon when light was low. Respiration was also similar in both warming treatments, because respiration temperature sensitivity was not sufficient to respond to the limited temperature differences between asymmetric and symmetric warming. We concluded that changes in daily mean temperatures, rather than changes in Tmin/Tmax, were sufficient for predicting ecosystem carbon fluxes in this reconstructed Mediterranean grassland system.

  4. The Contribution of Io-Raised Tides to Europa's Diurnally-Varying Surface Stresses

    NASA Technical Reports Server (NTRS)

    Rhoden, Alyssa Rose; Hurford, Terry A,; Manga, Michael

    2011-01-01

    Europa's icy surface records a rich history of geologic activity, Several features appear to be tectonic in origin and may have formed in response to Europa's daily-varying tidal stress [I]. Strike-slip faults and arcuate features called cycloids have both been linked to the patterns of stress change caused by eccentricity and obliquity [2J[3]. In fact, as Europa's obliquity has not been directly measured, observed tectonic patterns arc currently the best indicators of a theoretically supported [4] non-negligible obliquity. The diurnal tidal stress due to eccentricity is calculated by subtracting the average (or static) tidal shape of Europa generated by Jupiter's gravitational field from the instantaneous shape, which varies as Europa moves through its eccentric orbit [5]. In other words, it is the change of shape away from average that generates tidal stress. One might expect tidal contributions from the other large moons of Jupiter to be negligible given their size and the height of the tides they raise on Europa versus Jupiter's mass and the height of the tide it raises on Europa, However, what matters for tidally-induced stress is not how large the lo-raised bulge is compared to the Jupiter-raised bulge but rather the differences bet\\Veen the instantaneous and static bulges in each case. For example, when Europa is at apocenter, Jupiter raises a tide 30m lower than its static tide. At the same time, 10 raises a tide about 0.5m higher than its static tide. Hence, the change in Io's tidal distortion is about 2% of the change in the Jovian distortion when Europa is at apocenter

  5. A DIURNAL REFLECTANCE MODEL USING GRASS: SURFACE-SUBSTRATE INTERACTION AND INVERSE SOLUTION

    EPA Science Inventory

    The accuracy of using remote sensing data from earth orbiting radiometers can be improved by using a model that helps to separate the green-fraction in a canopy reflectance () from thatch and soil background, accounts for their diurnal changes, and inverts to a solution of a biop...

  6. A diurnal reflectance model using grass: Surface-substrate interaction and inverse solution - October 16, 2011

    EPA Science Inventory

    We report an analysis of canopy reflectance (ρ) experiment, using hand-held radiometer to measure distribution of biomass in a grass field. The analysis: 1) separates the green-fraction from thatch and soil background, 2) accounts for the changing diurnal ρ with the sun elevation...

  7. Diurnal variations of airborne pollen concentration and the effect of ambient temperature in three sites of Mexico City.

    PubMed

    Ríos, B; Torres-Jardón, R; Ramírez-Arriaga, E; Martínez-Bernal, A; Rosas, I

    2016-05-01

    Pollen is an important cause of allergic respiratory ailments in the Mexico City Metropolitan Area (MCMA). However, very little is known if ambient air temperature correlates with the early blooming of plants observed in other urban areas around the world. A research study was conducted during the dry season of 2012-2013 at three representative sites of the MCMA with different urban characteristics with the aim to understand the relationships between the profusion and diversity of pollen against temperature and other meteorological variables and degree of urbanization. Pollen samples were collected using a Hirst-type trap sampler in the sites: Merced (highly urbanized), Iztapalapa (medium-high urbanized) and Coyoacan (moderately urbanized). Urbanization levels were determined using a composite index based on population density, proportion of surface covered by construction and asphalt, and urban heat island intensity. A set of representative pollen sampling tapes were assayed under a light microscope at magnification of ×1,000 and converted to grains per cubic meter. The most representative pollen types found in the three sites were, regardless of urbanization levels were: Fraxinus, Cupressaceae/Taxodiaceae, Casuarina, Alnus, Myrtaceae, and Pinus. Total pollen concentration was greatest in the moderately urbanized area, although earlier blooming took place at the highly urbanized zone. Total pollen concentration in the medium-high urbanized site has the lowest because the green areas in this zone of MCMA are few. In a diurnal basis, the most abundant pollen types peaked near midday or in the afternoon evening at the three sites. A Spearman test showed a positive correlation among bihourly pollen concentrations, temperature and relative humidity in all sites, but wind speed just correlated in Iztapalapa and Coyoacan. The results obtained suggest that Urban Heat Island Intensity can disturb flowering periods and pollen concentrations, largely in the highly urbanized

  8. Diurnal variations of airborne pollen concentration and the effect of ambient temperature in three sites of Mexico City

    NASA Astrophysics Data System (ADS)

    Ríos, B.; Torres-Jardón, R.; Ramírez-Arriaga, E.; Martínez-Bernal, A.; Rosas, I.

    2016-05-01

    Pollen is an important cause of allergic respiratory ailments in the Mexico City Metropolitan Area (MCMA). However, very little is known if ambient air temperature correlates with the early blooming of plants observed in other urban areas around the world. A research study was conducted during the dry season of 2012-2013 at three representative sites of the MCMA with different urban characteristics with the aim to understand the relationships between the profusion and diversity of pollen against temperature and other meteorological variables and degree of urbanization. Pollen samples were collected using a Hirst-type trap sampler in the sites: Merced (highly urbanized), Iztapalapa (medium-high urbanized) and Coyoacan (moderately urbanized). Urbanization levels were determined using a composite index based on population density, proportion of surface covered by construction and asphalt, and urban heat island intensity. A set of representative pollen sampling tapes were assayed under a light microscope at magnification of ×1,000 and converted to grains per cubic meter. The most representative pollen types found in the three sites were, regardless of urbanization levels were: Fraxinus, Cupressaceae/Taxodiaceae, Casuarina, Alnus, Myrtaceae, and Pinus. Total pollen concentration was greatest in the moderately urbanized area, although earlier blooming took place at the highly urbanized zone. Total pollen concentration in the medium-high urbanized site has the lowest because the green areas in this zone of MCMA are few. In a diurnal basis, the most abundant pollen types peaked near midday or in the afternoon evening at the three sites. A Spearman test showed a positive correlation among bihourly pollen concentrations, temperature and relative humidity in all sites, but wind speed just correlated in Iztapalapa and Coyoacan. The results obtained suggest that Urban Heat Island Intensity can disturb flowering periods and pollen concentrations, largely in the highly urbanized

  9. The interrelationship between dengue incidence and diurnal ranges of temperature and humidity in a Sri Lankan city and its potential applications

    PubMed Central

    Ehelepola, N. D. B.; Ariyaratne, Kusalika

    2015-01-01

    Background Temperature, humidity, and other weather variables influence dengue transmission. Published studies show how the diurnal fluctuations of temperature around different mean temperatures influence dengue transmission. There are no published studies about the correlation between diurnal range of humidity and dengue transmission. Objective The goals of this study were to determine the correlation between dengue incidence and diurnal fluctuations of temperature and humidity in the Sri Lankan city of Kandy and to explore the possibilities of using that information for better control of dengue. Design We calculated the weekly dengue incidence in Kandy during the period 2003–2012, after collecting data on all of the reported dengue patients and estimated midyear populations. Data on daily maximum and minimum temperatures and night-time and daytime humidity were obtained from two weather stations, averaged, and converted into weekly data. The number of days per week with a diurnal temperature range (DTR) of >10°C and <10°C and the number of days per week with a diurnal humidity range (DHR) of >20 and <15% were calculated. Wavelet time series analysis was performed to determine the correlation between dengue incidence and diurnal ranges of temperature and humidity. Results There were negative correlations between dengue incidence and a DTR >10°C and a DHR >20% with 3.3-week and 4-week lag periods, respectively. Additionally, positive correlations between dengue incidence and a DTR <10°C and a DHR <15% with 3- and 4-week lag periods, respectively, were discovered. Conclusions These findings are consistent with the results of previous entomological studies and theoretical models of DTR and dengue transmission correlation. It is important to conduct similar studies on diurnal fluctuations of humidity in the future. We suggest ways and means to use this information for local dengue control and to mitigate the potential effects of the ongoing global reduction of

  10. Changes in seasonal and diurnal cycles of ozone and temperature in the eastern U.S.

    NASA Astrophysics Data System (ADS)

    Bloomer, Bryan J.; Vinnikov, Konstantin Y.; Dickerson, Russell R.

    2010-07-01

    The pollutant tropospheric ozone causes human health problems, and environmental degradation and acts as a potent greenhouse gas. Using long-term hourly observations at five US air quality monitoring surface stations we studied the seasonal and diel cycles of ozone concentrations and surface air temperature to examine the temporal evolution over the past two decades. Such an approach allows visualizing the impact of natural and anthropogenic processes on ozone; nocturnal inversion development, photochemistry, and stratospheric intrusion. Analysis of the result provides an option for determining the duration for a regulatory ozone season. The application of the method provides independent confirmation of observed changes and trends in the ozone and temperature data records as reported elsewhere. The results provide further evidence supporting the assertion that ozone reductions can be attributed to emission reductions as opposed to weather variation. Despite a (˜0.5 °C decade -1) daytime warming trend, ozone decreased by up to 6 ppb decade -1 during times of maximum temperature in the most polluted locations. Ozone also decreased across the emission reduction threshold of 2002 by 6-10 ppb indicating that emission reductions have been effective where and when it is most needed. Longer time series, and coupling with other data sources, may allow for the direct investigation of climate change influence on regional ozone air pollution formation and destruction over annual and daily time scales.

  11. Examination of diurnal temperature range at coterminous U.S. stations during Sept. 8-17, 2001

    NASA Astrophysics Data System (ADS)

    van Wijngaarden, W. A.

    2012-07-01

    The tragic events of Sept. 11, 2001 resulted in suspension of commercial flights over North America. It has been suggested that the diurnal temperature range (DTR) increased due to an absence of airplane contrails. This study examined hourly data observed at 288 stations. The average DTR, temperature, maximum/minimum temperature and relative humidity were found for each day in 2001 and compared to the average value occurring during 1975-2005. For the coterminous U.S., the DTR averaged over the period Sept. 11-14, 2001 was about 1°C larger than that found for the 3 days prior and after the flight ban. However, the day-to-day DTR does not correlate well with the flight ban. Plots of the change in DTR throughout North America during Sept. 8-17 show changes consistent with the natural progression of weather systems.

  12. Diurnal physical temperature at Sinus Iridum area retrieved from observations of Chinese Chang'E-1 microwave radiometer

    NASA Astrophysics Data System (ADS)

    Gong, Xiaohui; Jin, Ya-Qiu

    2012-04-01

    According to the incidence and azimuth angles of the Sun during observations of Chinese Chang'E-1 (CE-1) lunar satellite, brightness temperatures (Tb) at different lunar local time observed by the CE-1 multi-channel radiometers, especially at the Sinus Iridum (i.e. Bay of Rainbow) area, are collected from the transformation between the principal and local coordinates at the observed site, which demonstrates the Tb distribution and its diurnal variation. Based on a three-layer radiative transfer model of the lunar media, the CE-1 Tb data at 19.35 and 37.0 GHz channels are applied to invert the physical temperatures of both the dust and the regolith layer at Sinus Iridum area, where might be the CE-3 landing site, at different lunar local times. The physical temperature variations with the lunar local time and other geophysical parameters of lunar layered media are discussed.

  13. Surface Temperature Assimilation in Land Surface Models

    NASA Technical Reports Server (NTRS)

    Lakshmi, Venkataraman

    1999-01-01

    This paper examines the utilization of surface temperature as a variable to be assimilated in offline land surface hydrological models. Comparisons between the model computed and satellite observed surface temperatures have been carried out. The assimilation of surface temperature is carried out twice a day (corresponding to the AM and PM overpass of the NOAA10) over the Red-Arkansas basin in the Southwestern United States (31 degs 50 sec N - 36 degrees N, 94 degrees 30 seconds W - 104 degrees 3 seconds W) for a period of one year (August 1987 to July 1988). The effect of assimilation is to reduce the difference between the surface soil moisture computed for the precipitation and/or shortwave radiation perturbed case and the unperturbed case compared to no assimilation.

  14. Surface Temperature Assimilation in Land Surface Models

    NASA Technical Reports Server (NTRS)

    Lakshmi, Venkataraman

    1997-01-01

    This paper examines the utilization of surface temperature as a variable to be assimilated in offline land surface hydrological models. Comparisons between the model computed and satellite observed surface temperatures have been carried out. The assimilation of surface temperature is carried out twice a day (corresponding to the AM and PM overpass of the NOAA10) over the Red- Arkansas basin in the Southwestern United States (31 deg 50 min N - 36 deg N, 94 deg 30 min W - 104 deg 30 min W) for a period of one year (August 1987 to July 1988). The effect of assimilation is to reduce the difference between the surface soil moisture computed for the precipitation and/or shortwave radiation perturbed case and the unperturbed case compared to no assimilation.

  15. Isotopic exchange on the diurnal scale between near-surface snow and lower atmospheric water vapor at Kohnen station, East Antarctica

    NASA Astrophysics Data System (ADS)

    Ritter, François; Steen-Larsen, Hans Christian; Werner, Martin; Masson-Delmotte, Valérie; Orsi, Anais; Behrens, Melanie; Birnbaum, Gerit; Freitag, Johannes; Risi, Camille; Kipfstuhl, Sepp

    2016-07-01

    Quantifying the magnitude of post-depositional processes affecting the isotopic composition of surface snow is essential for a more accurate interpretation of ice core data. To achieve this, high temporal resolution measurements of both lower atmospheric water vapor and surface snow isotopic composition are required. This study presents continuous measurements of water vapor isotopes performed in East Antarctica (Kohnen station) from December 2013 to January 2014 using a laser spectrometer. Observations have been compared with the outputs of two atmospheric general circulation models (AGCMs) equipped with water vapor isotopes: ECHAM5-wiso and LMDZ5Aiso. During our monitoring period, the signals in the 2 m air temperature T, humidity mixing ratio q and both water vapor isotopes δD and δ18O are dominated by the presence of diurnal cycles. Both AGCMs simulate similar diurnal cycles with a mean amplitude 30 to 70 % lower than observed, possibly due to an incorrect simulation of the surface energy balance and the boundary layer dynamics. In parallel, snow surface samples were collected each hour over 35 h, with a sampling depth of 2-5 mm. A diurnal cycle in the isotopic composition of the snow surface is observed in phase with the water vapor, reaching a peak-to-peak amplitude of 3 ‰ for δD over 24 h (compared to 36 ‰ for δD in the water vapor). A simple box model treated as a closed system has been developed to study the exchange of water molecules between an air and a snow reservoir. In the vapor, the box model simulations show too much isotopic depletion compared to the observations. Mixing with other sources (advection, free troposphere) has to be included in order to fit the observations. At the snow surface, the simulated isotopic values are close to the observations with a snow reservoir of ˜ 5 mm depth (range of the snow sample depth). Our analysis suggests that fractionation occurs during sublimation and that vapor-snow exchanges can no longer

  16. Diurnal and seasonal variability of surface urban heat island phenomena in Warsaw (Poland)

    NASA Astrophysics Data System (ADS)

    Gawuć, Lech; Struzewska, Joanna

    2014-05-01

    The phenomenon of urbanization is an important environmental and social issue that modern society has to face. According to current estimates half of world's population lives in urban areas. It is expected that urban population will grow in the future. Urbanization and subsequent release of anthropogenic heat pollution lead to formation of an urban heat island (UHI). Development of UHI is a highly non-linear process (Kato et al., 2007) that depends on a number of factors such as magnitude of the anthropogenic heat flux, the texture of the city, local geophysical conditions and mesoscale meteorology (Sailor and Lu, 2004 after Narumi et al., 2003). We will present analyses of the magnitude and spatial extend of Surface Urban Heat Island (SUHI) in the capital of Poland, Warsaw. SUHI characteristics will be identified based on the Land Surface Temperature (LST) product derived for MODIS observations, which will be collected for time-series for April 2009 (34 acquisitions) and November 2011 (33 acquisitions). We will present maps of SUHI for morning, evening and night hours, for April and November separately. Several locations representing different types of land cover will be selected in order to analyze the temporal variability and amplitude of surface temperature in various parts of the city. In addition, air temperature from six automatic stations, maintained by Voivodeship Inspectorate of Environmental Protection, for periods coincident with satellite observations will be collected. Air and land temperature comparisons will be performed in order to investigate correspondence between surface UHI and air UHI. Impact of the synoptic conditions will be also discussed, with a particular caution for those terms when effect of UHI will be the strongest.

  17. Sea surface temperature of the coastal zones of France

    NASA Technical Reports Server (NTRS)

    Deschamps, P. Y.; Crepon, M.; Monget, J. M.; Verger, F. (Principal Investigator); Frouin, R.; Cassanet, J.; Wald, L.

    1982-01-01

    Thermal gradients in French coastal zones for the period of one year were mapped in order to enable a coherent study of certain oceanic features detectable by the variations in the sea surface temperature field and their evolution in time. The phenomena examined were mesoscale thermal features in the English Channel, the Bay of Biscay, and the northwestern Mediterranean; thermal gradients generated by French estuary systems; and diurnal heating in the sea surface layer. The investigation was based on Heat Capacity Mapping Mission imagery.

  18. Soil moisture from temperature measurements at the Earth's surface, update

    NASA Technical Reports Server (NTRS)

    Welker, J. E.

    1984-01-01

    Soil moisture budgets at the Earth's surface were investigated based on soil and atmospheric temperature variations. A number of data sets were plotted and statistically analyzed in order to accentuate the existence and the characteristics of mesoscale soil temperature extrema variations and their relations to other parameters. The correlations between diurnal temperature extrema for air and soil in drought and non-drought periods appear to follow different characteristic patterns, allowing an inference of soil moisture content from temperature data. The recovery of temperature extrema after a precipitation event also follows a characteristic power curve rise between two limiting values which is an indicator of evaporation rates. If these indicators are applied universally to regional temperature data, soil moisture content or drought conditions can be inferred directly from temperature measurements.

  19. Diurnal variations on a plasmaspheric flux tube - Light ion flows and F region temperature enhancements

    NASA Technical Reports Server (NTRS)

    Guiter, S. M.; Gombosi, T. I.; Rasmussen, C. E.

    1991-01-01

    The paper concentrates on the diurnal variations on a plasmaspheric flux tube modeled using a time-dependent multispecies one-stream interhemispheric model for plasma flows. The model takes into account the effects of ionization, charge exchange, recombination, collisions, heat conduction, and allows for external heat sources. The simulation is done for June solstice conditions during solar minimum. Focus is placed on the presence of large downward H(+) velocities at about 320-km altitude in the winter (southern) hemisphere, in early morning when the summer hemisphere is sunlit but the winter hemisphere is dark. In addition, an upward H(+) flux is seen in the Southern Hemisphere at altitudes above 2000 km when the sun rises in the northern end.

  20. The correlation between dengue incidence and diurnal ranges of temperature of Colombo district, Sri Lanka 2005–2014

    PubMed Central

    Ehelepola, N. D. B.; Ariyaratne, Kusalika

    2016-01-01

    Background Meteorological factors affect dengue transmission. Mechanisms of the way in which different diurnal temperatures, ranging around different mean temperatures, influence dengue transmission were published after 2011. Objective We endeavored to determine the correlation between dengue incidence and diurnal temperature ranges (DTRs) in Colombo district, Sri Lanka, and to explore the possibilities of using our findings to improve control of dengue. Design We calculated the weekly dengue incidence in Colombo during 2005–2014, after data on all of the reported dengue patients and estimated mid-year populations were collected. We obtained daily maximum and minimum temperatures from two Colombo weather stations, averaged, and converted them into weekly data. Weekly averages of DTR versus dengue incidence graphs were plotted and correlations observed. The count of days per week with a DTR of >7.5°C and <7.5°C were also calculated. Wavelet time series analysis was performed to determine the correlation between dengue incidence and DTR. Results We obtained a negative correlation between dengue incidence and a DTR>7.5°C with an 8-week lag period, and a positive correlation between dengue incidence and a DTR<7.5°C, also with an 8-week lag. Conclusions Large DTRs were negatively correlated with dengue transmission in Colombo district. We propose to take advantage of that in local dengue control efforts. Our results agree with previous studies on the topic and with a mathematical model of relative vectorial capacity of Aedes aegypti. Global warming and declining DTR are likely to favor a rise of dengue, and we suggest a simple method to mitigate this. PMID:27566717

  1. Initial Changes in the Transcriptome of Euphorbia esula Seeds Induced to Germinate with a Combination of Constant and Diurnal Alternating Temperatures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated transcriptome changes in Euphorbia esula (leafy spurge) seeds with a focus on the effect of constant and diurnal fluctuating temperature on dormancy and germination. Leafy spurge seeds do not germinate when incubated for 21 days at 20°C constant temperatures, but nearly 30% germinate...

  2. Effects of diurnal temperature variation on microbial community and petroleum hydrocarbon biodegradation in contaminated soils from a sub-Arctic site.

    PubMed

    Akbari, Ali; Ghoshal, Subhasis

    2015-12-01

    Contaminated soils are subject to diurnal and seasonal temperature variations during on-site ex-situ bioremediation processes. We assessed how diurnal temperature variations similar to that in summer at the site from which petroleum hydrocarbon-contaminated soil was collected affect the soil microbial community and the extent of biodegradation of petroleum hydrocarbons compared with constant temperature regimes. Microbial community analyses for 16S rRNA and alkB genes by pyrosequencing indicated that the microbial community for soils incubated under diurnal temperature variation from 5°C to 15°C (VART5-15) evolved similarly to that for soils incubated at constant temperature of 15°C (CST15). In contrast, under a constant temperature of 5°C (CST5), the community evolved significantly different. The extent of biodegradation of C10-C16 hydrocarbons in the VART5-15 systems was 48%, comparable with the 41% biodegradation in CST15 systems, but significantly higher than CST5 systems at 11%. The enrichment of Gammaproteobacteria was observed in the alkB gene-harbouring communities in VART5-15 and CST15 but not in CST5 systems. However, the Actinobacteria was abundant at all temperature regimes. The results suggest that changes in microbial community composition as a result of diurnal temperature variations can significantly influence petroleum hydrocarbon bioremediation performance in cold regions. PMID:25808640

  3. Constant diurnal temperature regime alters the impact of simulated climate warming on a tropical pseudoscorpion

    PubMed Central

    Zeh, Jeanne A.; Bonilla, Melvin M.; Su, Eleanor J.; Padua, Michael V.; Anderson, Rachel V.; Zeh, David W.

    2014-01-01

    Recent theory suggests that global warming may be catastrophic for tropical ectotherms. Although most studies addressing temperature effects in ectotherms utilize constant temperatures, Jensen's inequality and thermal stress considerations predict that this approach will underestimate warming effects on species experiencing daily temperature fluctuations in nature. Here, we tested this prediction in a neotropical pseudoscorpion. Nymphs were reared in control and high-temperature treatments under a constant daily temperature regime, and results compared to a companion fluctuating-temperature study. At constant temperature, pseudoscorpions outperformed their fluctuating-temperature counterparts. Individuals were larger, developed faster, and males produced more sperm, and females more embryos. The greatest impact of temperature regime involved short-term, adult exposure, with constant temperature mitigating high-temperature effects on reproductive traits. Our findings demonstrate the importance of realistic temperature regimes in climate warming studies, and suggest that exploitation of microhabitats that dampen temperature oscillations may be critical in avoiding extinction as tropical climates warm. PMID:24424082

  4. A comparison of Argo nominal surface and near-surface temperature for validation of AMSR-E SST

    NASA Astrophysics Data System (ADS)

    Liu, Zenghong; Chen, Xingrong; Sun, Chaohui; Wu, Xiaofen; Lu, Shaolei

    2016-06-01

    Satellite SST (sea surface temperature) from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) is compared with in situ temperature observations from Argo profiling floats over the global oceans to evaluate the advantages of Argo NST (near-surface temperature: water temperature less than 1 m from the surface). By comparing Argo nominal surface temperature (~5 m) with its NST, a diurnal cycle caused by daytime warming and nighttime cooling was found, along with a maximum warming of 0.08±0.36°C during 14:00-15:00 local time. Further comparisons between Argo 5-m temperature/Argo NST and AMSR-E SST retrievals related to wind speed, columnar water vapor, and columnar cloud water indicate warming biases at low wind speed (<5 m/s) and columnar water vapor >28 mm during daytime. The warming tendency is more remarkable for AMSR-E SST/Argo 5-m temperature compared with AMSR-E SST/Argo NST, owing to the effect of diurnal warming. This effect of diurnal warming events should be excluded before validation for microwave SST retrievals. Both AMSR-E nighttime SST/Argo 5-m temperature and nighttime SST/Argo NST show generally good agreement, independent of wind speed and columnar water vapor. From our analysis, Argo NST data demonstrated their advantages for validation of satellite-retrieved SST.

  5. Temperature-dependent Luttinger surfaces.

    PubMed

    Ito, T; Chainani, A; Haruna, T; Kanai, K; Yokoya, T; Shin, S; Kato, R

    2005-12-01

    The Luttinger surface of an organic metal (TTF-TCNQ), possessing charge order and spin-charge separated band dispersions, is investigated using temperature-dependent angle-resolved photoemission spectroscopy. The Luttinger surface topology, obtained from momentum distribution curves, changes from quasi-2D (dimensional) to quasi-1D with temperature. The high temperature quasi-2D surface exhibits 4kF charge-density-wave (CDW) superstructure in the TCNQ derived holon band, in the absence of 2kF order. Decreasing temperature results in quasi-1D nested 2kF CDW order in the TCNQ spinon band and in the TTF surface. The results establish the link in momentum space between charge order and spin-charge separation in a Luttinger liquid. PMID:16384402

  6. Seasonal variations of diurnal and semidiurnal tidal-period perturbations in mesopause region temperature and zonal and meridional winds above Fort Collins, Colorado (40 degrees North, 105 degrees West) based on sodium-Lidar observation over full diurnal cycles

    NASA Astrophysics Data System (ADS)

    Yuan, Tao

    With continued efforts by all the members (past and present) in the Na-Lidar group at Colorado State University, the lidar system was capable of simultaneous measurement of mesopause region temperature and horizontal wind at night. Since May 2002, the CSU fluorescence lidar system has been able to perform these observations on 24-hour continuous basis for a long-period, weather permitting. The key factor, which makes lidar observation under sunlit conditions possible, is a pair of robust (reliable and stable) Faraday filters that reduces the sky background. To attain such a Faraday Filter, in this thesis we developed and implemented dual temperature control (to +/-0.1K) of sodium cell inside the filters, and of the cell's tip-off region. The dual control allows independent setting of cell temperature and the Na vapor pressure, thus stabilizing Na vapor density in the cell and the transmission function of the Faraday filter. This 24-hour continuous observation capability provided us with the first yearlong data set with campaigns of full diurnal cycle coverage leading to the first study of diurnal and semidiurnal tides of mesopause region temperature, zonal and meridional winds based on ground based observation. The yearlong data set include a total of 1,491 hours with 659 hours under sunlit conditions, within which there are 29 sets of 24-hour continuous observation. We binned these 29 data sets into bimonthly time series and performed harmonic analysis to deduce diurnal mean, diurnal and semidiurnal tidal-period oscillations of the mesopause region temperature, zonal and meridional winds over Fort Collins, CO. The resulting bimonthly tidal amplitudes and phases are compared to the predictions of Global Scale Wave Models (GSWM00 and GSWM02) and Thermosphere, Ionosphere, Mesosphere and Electrodynamics - General Circulation Model (TIME-GCM02). Other than diurnal temperatures in Nov--Dec, we found excellent agreement between observation and GSWM00 model for diurnal

  7. Does river restoration affect diurnal and seasonal changes to surface water quality? A study along the Thur River, Switzerland.

    PubMed

    Chittoor Viswanathan, Vidhya; Molson, John; Schirmer, Mario

    2015-11-01

    Changes in river water quality were investigated along the lower reach of the Thur River, Switzerland, following river restoration and a summer storm event. River restoration and hydrological storm events can each cause dramatic changes to water quality by affecting various bio-geochemical processes in the river, but have to date not been well documented, especially in combination. Evaluating the success of river restoration is often restricted in large catchments due to a lack of high frequency water quality data, which are needed for process understanding. These challenges were addressed in this study by measuring water quality parameters including dissolved oxygen (DO), temperature, pH, electrical conductivity (EC), nitrate and dissolved organic carbon (DOC) with a high temporal frequency (15 min-1h) over selected time scales. In addition, the stable isotopes of water (δD and δ(18)O-H2O) as well as those of nitrate (δ(15)N-NO3(-) and δ(18)O-NO3(-)) were measured to follow changes in water quality in response to the hydrological changes in the river. To compare the spatial distribution of pre- and post-restoration water quality, the sampling stations were chosen upstream and downstream of the restored section. The diurnal and seasonal changes were monitored by conducting 24-hour campaigns in three seasons (winter, summer and autumn) in 2012 and 2013. The amplitude of the diurnal changes of the various observed parameters showed significant seasonal and spatial variability. Biological processes--mainly photosynthesis and respiration--were found to be the major drivers of these diurnal cycles. During low flow in autumn, a reduction of nitrate (attributed to assimilation by autotrophs) in the pre-dawn period and a production of DOC during the daytime (attributed to photosynthesis) were observed downstream of the restored site. Further, a summer storm event was found to override the influence of these biological processes that control the diurnal changes. High

  8. High frequency thermal emission from the lunar surface and near surface temperature of the Moon from Chang’E-2 microwave radiometer

    NASA Astrophysics Data System (ADS)

    Fang, Tuo; Fa, Wenzhe

    2014-04-01

    Near surface temperature of the Moon and thermal behaviors of the lunar regolith can provide important information for constraining thermal and magmatic evolution models of the Moon and engineering constrains for in situ lunar exploration system. In this study, China’s Chang’E-2 (CE-2) microwave radiometer (MRM) data at high frequency channels are used to investigate near surface temperature of the Moon given the penetration ability of microwave into the desiccated and porous lunar regolith. Factors that affect high frequency brightness temperature (TB), such as surface slope, solar albedo and dielectric constant, are analyzed first using a revised Racca’s temperature model. Radiative transfer theory is then used to model thermal emission from a semi-infinite regolith medium, with considering dielectric constant and temperature profiles within the regolith layer. To decouple the effect of diurnal temperature variation in the uppermost lunar surface, diurnal averaged brightness temperatures at high frequency channels are used to invert mean diurnal surface and subsurface temperatures based on their bilinear profiles within the regolith layer. Our results show that, at the scale of the spatial resolution of CE-2 MRM, surface slope of crater wall varies typically from about 20° to 30°, and this causes a variation in TB about 10-15 K. Solar albedo can give rise to a TB difference of about 5-10 K between maria and highlands, whereas a ∼2-8 K difference can be compensated by the dielectric constant on the other hand. Inversion results indicate that latitude (ϕ) variations of the mean diurnal surface and subsurface temperatures follow simple rules as cos0.30ϕ and cos0.36ϕ, respectively. The inverted mean diurnal temperature profiles at the Apollo 15 and 17 landing sites are also compared with the Apollo heat flow experiment data, showing an inversion uncertainty <4 K for surface temperature and <1 K for subsurface temperature.

  9. The Sensitivity of Land Surface Model Simulations to Differences in Diurnal Variations In Two Bias Corrected Reanalysis Products

    NASA Astrophysics Data System (ADS)

    Berg, A. A.; Famiglietti, J. S.

    2001-12-01

    Bias reduced forcing datasets were produced from the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Center for Environmental Prediction (NCEP)/ National Center for Atmospheric Research (NCAR) reanalysis. For each forcing product, an identical bias reduction scheme was applied whereby the reanalysis fields were adjusted to match monthly mean observations. The two products were then used as forcing for a land surface model. Despite the identical bias correction applied to each reanalysis, differences to the diurnal forcing are manifest in LSM model predictions of soil moisture status, evaporation, snow water equivalence, and runoff. Magnitudes of these differences and resultant effects on hydrological flux simulation are compared for 20 control watersheds distributed across the North American continent with a particular emphasis placed on which of the input variations (e.g. precipitation and radiation forcing) dominate the differences to model output, what role land surface characteristics play (e.g. soils, vegetation, topography), and how these vary over the continent.

  10. Diurnal variation in the control of ventilation in response to rising body temperature during exercise in the heat.

    PubMed

    Tsuji, Bun; Honda, Yasushi; Kondo, Narihiko; Nishiyasu, Takeshi

    2016-08-01

    We investigated whether heat-induced hyperventilation during exercise is affected by time of day, as diurnal variation leads to higher core temperatures in the evening. Nineteen male subjects were divided into two experiments (protocol 1, n = 10 and protocol 2, n = 9). In protocol 1, subjects performed cycle exercise at 50% peak oxygen uptake in the heat (37°C and 50% RH) in the morning (0600) and evening (1800). Results showed that baseline resting and exercising esophageal temperature (Tes) were significantly (0.5°C) higher in the evening than morning. Minute ventilation (V̇e) increased from 54.3 ± 7.9 and 54.9 ± 6.8 l/min at 10 min to 71.4 ± 8.1 and 76.5 ± 11.8 l/min at 48.5 min in the morning and evening, respectively (both P < 0.01). Time of day had no effect on V̇e (P = 0.44). When V̇e as the output response was plotted against Tes as thermal input, the Tes threshold for increases in V̇e was higher in the evening than morning (37.2 ± 0.7 vs. 36.6 ± 0.6°C, P = 0.009), indicating the ventilatory response to the same core temperature is smaller in the evening. In protocol 2, the circadian rhythm-related higher resting Tes seen in the evening was adjusted down to the same temperature seen in the morning by immersing the subject in cold water. Importantly, the time course of changes in V̇e during exercise were smaller in the evening, but the threshold for V̇e remained higher in the evening than morning (P < 0.001). Collectively, those results suggest that time of day has no effect on time course hyperventilation during exercise in the heat, despite the higher core temperatures in the evening. This is likely due to diurnal variation in the control of ventilation in response to rising core temperature. PMID:27335282

  11. Impact of an improved WRF urban canopy model on diurnal air temperature simulation over northern Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Chuan-Yao; Su, Chiung-Jui; Kusaka, Hiroyuki; Akimoto, Yuko; Sheng, Yang-Fan; Huang, -Chuan, Jr.; Hsu, Huang-Hsiung

    2016-02-01

    This study evaluates the impact of urbanization over northern Taiwan using the Weather Research and Forecasting (WRF) Model coupled with the Noah land-surface model and a modified urban canopy model (WRF-UCM2D). In the original UCM coupled to WRF (WRF-UCM), when the land use in the model grid is identified as "urban", the urban fraction value is fixed. Similarly, the UCM assumes the distribution of anthropogenic heat (AH) to be constant. This may not only lead to over- or underestimation of urban fraction and AH in urban and non-urban areas, but spatial variation also affects the model-estimated temperature. To overcome the abovementioned limitations and to improve the performance of the original UCM model, WRF-UCM is modified to consider the 2-D urban fraction and AH (WRF-UCM2D).The two models were found to have comparable temperature simulation performance for urban areas, but large differences in simulated results were observed for non-urban areas, especially at nighttime. WRF-UCM2D yielded a higher correlation coefficient (R2) than WRF-UCM (0.72 vs. 0.48, respectively), while bias and RMSE achieved by WRF-UCM2D were both significantly smaller than those attained by WRF-UCM (0.27 and 1.27 vs. 1.12 and 1.89, respectively). In other words, the improved model not only enhanced correlation but also reduced bias and RMSE for the nighttime data of non-urban areas. WRF-UCM2D performed much better than WRF-UCM at non-urban stations with a low urban fraction during nighttime. The improved simulation performance of WRF-UCM2D in non-urban areas is attributed to the energy exchange which enables efficient turbulence mixing at a low urban fraction. The result of this study has a crucial implication for assessing the impacts of urbanization on air quality and regional climate.

  12. Mitigating errors in surface temperature forecasts using approximate radiation updates

    NASA Astrophysics Data System (ADS)

    Hogan, Robin J.; Bozzo, Alessio

    2015-06-01

    Due to computational expense, the radiation schemes in many weather and climate models are called infrequently in time and/or on a reduced spatial grid. The former can lead to a lag in the diurnal cycle of surface temperature, while the latter can lead to large surface temperature errors at coastal land points due to surface fluxes computed over the ocean being used where the skin temperature and surface albedo are very different. This paper describes a computationally efficient solution to these problems, in which the surface longwave and shortwave fluxes are updated every time step and grid point according to the local skin temperature and albedo. In order that energy is conserved, it is necessary to compute the change to the net flux profile consistent with the changed surface fluxes. The longwave radiation scheme has been modified to compute also the rate of change of the profile of upwelling longwave flux with respect to the value at the surface. Then at each grid point and time step, the upwelling flux and heating-rate profiles are updated using the new value of skin temperature. The computational cost of performing approximate radiation updates in the ECMWF model is only 2% of the cost of the full radiation scheme, so increases the overall cost of the model by only of order 0.2%. Testing the new scheme by running daily 5 day forecasts over an 8 month period reveals significant improvement in 2 m temperature forecasts at coastal stations compared to observations.

  13. Impact of aerosol indirect effect on surface temperature over East Asia

    PubMed Central

    Huang, Yan; Dickinson, Robert E.; Chameides, William L.

    2006-01-01

    A regional coupled climate–chemistry–aerosol model is developed to examine the impacts of anthropogenic aerosols on surface temperature and precipitation over East Asia. Besides their direct and indirect reduction of short-wave solar radiation, the increased cloudiness and cloud liquid water generate a substantial downward positive long-wave surface forcing; consequently, nighttime temperature in winter increases by +0.7°C, and the diurnal temperature range decreases by −0.7°C averaged over the industrialized parts of China. Confidence in the simulated results is limited by uncertainties in model cloud physics. However, they are broadly consistent with the observed diurnal temperature range decrease as reported in China, suggesting that changes in downward long-wave radiation at the surface are important in understanding temperature changes from aerosols. PMID:16537432

  14. Boreal lakes moderate seasonal and diurnal temperature variation and perturb atmospheric circulation: Analyses in the Community Earth System Model 1 (CESM1)

    SciTech Connect

    Subin, Zachary M.; Murphy, Lisa N.; Li, Fiyu; Bonfils, Celine; Riley, William J.

    2012-01-15

    We used a lake thermal physics model recently coupled into the Community Earth System Model 1 (CESM1) to study the effects of lake distribution in present and future climate. Under present climate, correcting the large underestimation of lake area in CESM1 (denoted CCSM4 in the configuration used here) caused 1 °C spring decreases and fall increases in surface air temperature throughout large areas of Canada and the US. Simulated summer surface diurnal air temperature range decreased by up to 4 °C, reducing CCSM4 biases. These changes were much larger than those resulting from prescribed lake disappearance in some present-day permafrost regions under doubled-CO2 conditions. Correcting the underestimation of lake area in present climate caused widespread high-latitude summer cooling at 850 hPa. Significant remote changes included decreases in the strength of fall Southern Ocean westerlies. We found significantly different winter responses when separately analysing 45-yr subperiods, indicating that relatively long simulations are required to discern the impacts of surface changes on remote conditions. We also investigated the surface forcing of lakes using idealised aqua-planet experiments which showed that surface changes of 2 °C in the Northern Hemisphere extra-tropics could cause substantial changes in precipitation and winds in the tropics and Southern Hemisphere. Shifts in the Inter-Tropical Convergence Zone were opposite in sign to those predicted by some previous studies. Zonal mean circulation changes were consistent in character but much larger than those occurring in the lake distribution experiments, due to the larger magnitude and more uniform surface forcing in the idealised aqua-planet experiments.

  15. Diurnal Soil Temperature Effects within the Globe[R] Program Dataset

    ERIC Educational Resources Information Center

    Witter, Jason D.; Spongberg, Alison L.; Czajkowski, Kevin P.

    2007-01-01

    Long-term collection of soil temperature with depth is important when studying climate change. The international program GLOBE[R] provides an excellent opportunity to collect such data, although currently endorsed temperature collection protocols need to be refined. To enhance data quality, protocol-based methodology and automated data logging,…

  16. Method for measuring surface temperature

    SciTech Connect

    Baker, Gary A.; Baker, Sheila N.; McCleskey, T. Mark

    2009-07-28

    The present invention relates to a method for measuring a surface temperature using is a fluorescent temperature sensor or optical thermometer. The sensor includes a solution of 1,3-bis(1-pyrenyl)propane within a 1-butyl-1-1-methyl pyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid solvent. The 1,3-bis(1-pyrenyl)propane remains unassociated when in the ground state while in solution. When subjected to UV light, an excited state is produced that exists in equilibrium with an excimer. The position of the equilibrium between the two excited states is temperature dependent.

  17. Surface Temperature variability from AIRS.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Dang, V. T.; Aumann, H. H.

    2015-12-01

    To address the existence and possible causes of the climate hiatus in the Earth's global temperature we investigate the trends and variability in the surface temperature using retrievals obtained from the measurements by the Atmospheric Infrared Sounder (AIRS) and its companion instrument, the Advanced Microwave Sounding Unit (AMSU), onboard of Aqua spacecraft in 2002-2014for the day and night conditions. The data used are L3 monthly means on a 1x1degree spatial grid. We separate the land and ocean temperatures, as well as temperatures in Artic, Antarctic and desert regions. We compare the satellite data with the new surface data produced by Karl et al. (2015) who denies the reality of the climate hiatus. The difference in the regional trends can help to explain why the global surface temperature remains almost unchanged but the frequency of occurrence of the extreme events increases under rising anthropogenic forcing. The day-night difference is an indicator of the anthropogenic trend. This work was supported by the Jet Propulsion Laboratory of the California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  18. Atmospheric leakage and condensate production in NASA's biomass production chamber. Effect of diurnal temperature cycles

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; Drese, John H.; Sager, John C.

    1991-01-01

    A series of tests were conducted to monitor atmospheric leakage rate and condensate production in NASA's Biomass Production Chamber (BPC). Water was circulated through the 64 plant culture trays inside the chamber during the tests but no plants were present. Environmental conditions were set to a 12-hr photoperiod with either a matching 26 C (light)/20 C (dark) thermoperiod, or a constant 23 C temperature. Leakage, as determined by carbon dioxide decay rates, averaged about 9.8 percent for the 26 C/20 C regime and 7.3 percent for the constant 23 C regime. Increasing the temperature from 20 C to 26 C caused a temporary increase in pressure (up to 0.5 kPa) relative to ambient, while decreasing the temperature caused a temporary decrease in pressure of similar magnitude. Little pressure change was observed during transition between 23 C (light) and 23 C (dark). The lack of large pressure events under isothermal conditions may explain the lower leakage rate observed. When only the plant support inserts were placed in the culture trays, condensate production averaged about 37 liters per day. Placing acrylic germination covers over the tops of culture trays reduced condensate production to about 7 liters per day. During both tests, condensate production from the lower air handling system was 60 to 70 percent greater than from the upper system, suggesting imbalances exist in chilled and hot water flows for the two air handling systems. Results indicate that atmospheric leakage rates are sufficiently low to measure CO2 exchange rates by plants and the accumulation of certain volatile contaminants (e.g., ethylene). Control system changes are recommended in order to balance operational differences (e.g., humidity and temperature) between the two halves of the chamber.

  19. Regional Variations in U.S. Diurnal Temperature Range for the 11 14 September 2001 Aircraft Groundings: Evidence of Jet Contrail Influence on Climate.

    NASA Astrophysics Data System (ADS)

    Travis, David J.; Carleton, Andrew M.; Lauritsen, Ryan G.

    2004-03-01

    The grounding of all commercial aircraft within U.S. airspace for the 3-day period following the 11 September 2001 terrorist attacks provides a unique opportunity to study the potential role of jet aircraft contrails in climate. Contrails are most similar to natural cirrus clouds due to their high altitude and strong ability to efficiently reduce outgoing infrared radiation. However, they typically have a higher albedo than cirrus; thus, they are better at reducing the surface receipt of incoming solar radiation. These contrail characteristics potentially suppress the diurnal temperature range (DTR) when contrail coverage is both widespread and relatively long lasting over a specific region. During the 11 14 September 2001 grounding period natural clouds and contrails were noticeably absent on high-resolution satellite imagery across the regions that typically receive abundant contrail coverage. A previous analysis of temperature data for the grounding period reported an anomalous increase in the U.S.-averaged, 3-day DTR value. Here, the spatial variation of the DTR anomalies as well as the separate contributions from the maximum and minimum temperature departures are analyzed. These analyses are undertaken to better evaluate the role of jet contrail absence and synoptic weather patterns during the grounding period on the DTR anomalies.It is shown that the largest DTR increases occurred in regions where contrail coverage is typically most prevalent during the fall season (from satellite-based contrail observations for the 1977 79 and 2000 01 periods). These DTR increases occurred even in those areas reporting positive departures of tropospheric humidity, which may reduce DTR, during the grounding period. Also, there was an asymmetric departure from the normal maximum and minimum temperatures suggesting that daytime temperatures responded more to contrail absence than did nighttime temperatures, which responded more to synoptic conditions. The application of a

  20. Variability and trend of diurnal temperature range in China and their relationship to total cloud cover and sunshine duration

    NASA Astrophysics Data System (ADS)

    Xia, X.

    2013-05-01

    This study aims to investigate the effect of total cloud cover (TCC) and sunshine duration (SSD) in the variation of diurnal temperature range (DTR) in China during 1954-2009. As expected, the inter-annual variation of DTR was mainly determined by TCC. Analysis of trends of 30-year moving windows of DTR and TCC time series showed that TCC changes could account for that of DTR in some cases. However, TCC decreased during 1954-2009, which did not support DTR reduction across China. DTRs under sky conditions such as clear, cloudy and overcast showed nearly the same decreasing rate that completely accounted for the overall DTR reduction. Nevertheless, correlation between SSD and DTR was weak and not significant under clear sky conditions in which aerosol direct radiative effect should be dominant. Furthermore, 30-60% of DTR reduction was associated with DTR decrease under overcast conditions in south China. This implies that aerosol direct radiative effect appears not to be one of the main factors determining long-term changes in DTR in China.

  1. Effect of diurnal and seasonal temperature variation on Cussac cave ventilation using co2 assessment

    NASA Astrophysics Data System (ADS)

    Peyraube, Nicolas; Lastennet, Roland; Villanueva, Jessica Denila; Houillon, Nicolas; Malaurent, Philippe; Denis, Alain

    2016-05-01

    Cussac cave was investigated to assess the cave air temperature variations and to understand its ventilation regime. This cave is located in an active karst system in the south west part of France. It has a single entrance and is considered as a cold air trap. In this study, air mass exchanges were probed. Measurements of temperature and Pco2 with a 30-min frequency were made in several locations close to the cave entrance. Speed of the air flow was also measured at the door of cave entrance. Results show that cave air Pco2 varies from 0.18 to 3.33 %. This cave appears to be a CO2 source with a net mass of 2319 tons blown in 2009. Carbon-stable isotope of CO2 (13Cco2) ranges from -20.6 ‰ in cold season to -23.8 ‰ in warm season. Cave air is interpreted as a result of a mix between external air and an isotopically depleted air, coming from the rock environment. The isotopic value of the light member varies through time, from -23.9 to -22.5 ‰. Furthermore, this study ascertains that the cave never stops in communicating with the external air. The ventilation regime is identified. (1) In cold season, the cave inhales at night and blows a little at the warmest hours. However, in warm season, (2) cave blows at night, but (3) during the day, a convection loop takes place in the entrance area and prevents the external air from entering the cave, confirming the cold air trap.

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

    NASA Technical Reports Server (NTRS)

    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.

  3. The long-term trend in the diurnal temperature range over Asia and its natural and anthropogenic causes

    NASA Astrophysics Data System (ADS)

    Liu, Lin; Li, Zhanqing; Yang, Xin; Gong, Hainan; Li, Chao; Xiong, Anyuan

    2016-04-01

    Understanding the causes of long-term temperature trends is at the core of climate change studies. Any observed trend can result from natural variability or anthropogenic influences or both. In the present study, we evaluated the performance of 18 climate models from the Coupled Model Intercomparison Project Phase 5 on simulating the Asian diurnal temperature range (DTR) and explored the potential causes of the long-term trend in the DTR by examining the response of the DTR to natural forcing (volcanic aerosols and solar variability) and anthropogenic forcing (anthropogenic greenhouse gases (GHG) and aerosols) in the historical period of 1961-2005. For the climatology, the multimodel ensemble mean reproduced the geographical distribution and amplitude of the DTR over eastern China and India but underestimated the magnitudes of the DTR over the Tibetan Plateau and the high-latitude regions of the Asian continent. These negative biases in the DTR over frigid zones existed in most models. Seasonal biases in the DTR pattern from models were similar to the bias in the annual mean DTR pattern. Based on three selected state-of-the-art models, the observed decreasing trend in the DTR over Asia was reasonably reproduced in the all-forcing run. A comparison of separate forcing experiments revealed that anthropogenic forcing plays the dominant role in the declining trend in the DTR. Observations and model simulations showed that GHG forcing is mainly responsible for the negative trends in the DTR over Asia but that anthropogenic aerosol forcing was also behind the decreasing trend in the DTR over China and especially over eastern China.

  4. MODIS Global Sea Surface Temperature

    NASA Technical Reports Server (NTRS)

    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

  5. The impact of river restoration on the diurnal and seasonal surface water quality changes in the Thur catchment in Switzerland

    NASA Astrophysics Data System (ADS)

    Chittoor Viswanathan, V.; Schirmer, M.

    2012-12-01

    The importance of river restoration projects can only be realized upon evaluating their success or failure in a region mainly with regards to water quality, ecological adaptations and flood mitigation. The lack of temporal data in many restoration projects demand a spatial analysis of water quality parameters between the restored and unrestored parts of the river. Further, in large catchments there is a lack of water quality data in high frequency which are needed for the understanding of stream biogeochemical processes. This study addresses these challenges.The Thur catchment (1696 km2) in North eastern Switzerland is the chosen study area. The water quality along the lower part of the river reach has been analyzed with regard to the existing land use and a comparison is made with the water quality in the restored river sections of the river. A restored river section at Niederneunforn has been heavily monitored as part of the RECORD project (http://www.cces.ethz.ch/projects/nature/Record) and this data is vital for the present work. The water quality changes are to be observed by relating to some of the basic parameters like temperature, pH, alkalinity, electrical conductivity (EC), dissolved oxygen (DO), dissolved organic carbon (DOC), the concentration of ions like chloride, nitrate, nitrite, sulphate, ortho-phosphate, ammonium, magnesium, potassium and calcium (Ca). The diurnal and seasonal water quality changes are observed by conducting 24 hour sampling campaigns in summer (average flow 25 m3/s) and in winter (average flow 50 m3/s). Five monitoring stations are chosen in the lower part of the river which are situated two upstream of the monitored restored section and two downstream of it. The samples are collected at each station at an hourly interval for 24 hours using auto samplers. A new method of sampling is developed by calculating the average velocity of the river between the stations using a 1D hydraulic model (HEC-RAS) with the forecasted discharge on

  6. Decoding the Surface Temperature Record

    NASA Astrophysics Data System (ADS)

    Rhines, A. N.; Tingley, M.; McKinnon, K. A.; Huybers, P. J.

    2014-12-01

    Historical temperature observations from surface stations have been recorded using a variety of units and levels of precision, with metadata that are often incomplete. As a result, the amount of rounding applied to these observations is generally unknown, posing a challenge to statistical methods that are sensitive to the use of discrete data. Methods used to infer distributional changes often assume that data are continuously distributed and can only be reliably applied when the specific discreteness of each sample is known. We present a new technique, termed `precision-decoding,' that identifies the original precision and units of time series data. Applying it to the GHCND database, we identify temporal and spatial patterns in the precision and units used by surface stations. We show that many archived values have been offset from the original observations due to double-rounding in the presence of conversion between Fahrenheit and Celsius, and provide additional metrics to identify stations in need of further quality control. While the discreteness of the data is unlikely to have influenced global mean temperature trends, we show that it can affect higher-order moments of the temperature distribution such as the variance or skewness, and that it can alter the apparent frequency of record-breaking events.

  7. The impacts of heterogeneous land surface fluxes on the diurnal cycle precipitation: A framework for improving the GCM representation of land-atmosphere interactions

    NASA Astrophysics Data System (ADS)

    Wu, Chien-Ming; Lo, Min-Hui; Chen, Wei-Ting; Lu, Chia-Tsung

    2015-05-01

    The present study aims to investigate the modulation of the diurnal cycle precipitation by heterogeneous land surface fluxes. By combining the National Center for Atmospheric Research Community Land Model (CLM) and vector vorticity equation cloud-resolving model (VVM), experiments are designed to understand the responses of diurnal convection to heterogeneous land surface forcings of various spatial scales and intensities. To delineate the land-atmosphere interactions, a two-step off-line approach is adopted. First, the CLM is driven by observational atmospheric forcing with different characteristic length scales and magnitudes. While the surface fluxes from the CLM show no significant difference in the domain-averaged values, their spatial distribution responds significantly to the precipitation heterogeneity. In the second step, the derived CLM surface fluxes are used to drive the VVM. Results show that the timing of precipitation accelerates with increasing magnitude of surface flux perturbation, while the mean and diurnal ranges of precipitation roughly remain the same. The larger perturbation magnitude enhances the boundary layer vertical kinetic energy, which advances the development of the boundary layer. On the other hand, the mean and diurnal ranges of precipitation increase significantly, and the timing of initial precipitation delays with increasing perturbation length scale. The inland breeze induced by the large patches of surface fluxes tends to enhance the mesoscale organization of deep convection, hence the stronger precipitation. The present results highlight the importance of taking heterogeneous land surface fluxes into consideration in future development of general circulation model convection parameterizations associated with land and atmosphere interactions.

  8. High temperature limits in vivo pollen tube growth rates by altering diurnal carbohydrate balance in field-grown Gossypium hirsutum pistils.

    PubMed

    Snider, John L; Oosterhuis, Derrick M; Loka, Dimitra A; Kawakami, Eduardo M

    2011-07-15

    It has recently been reported that high temperature slows in vivo pollen tube growth rates in Gossypium hirsutum pistils under field conditions. Although numerous physical and biochemical pollen-pistil interactions are necessary for in vivo pollen tube growth to occur, studies investigating the influence of heat-induced changes in pistil biochemistry on in vivo pollen tube growth rates are lacking. We hypothesized that high temperature would alter diurnal pistil biochemistry and that pollen tube growth rates would be dependent upon the soluble carbohydrate content of the pistil during pollen tube growth. G. hirsutum seeds were sown on different dates to obtain flowers exposed to contrasting ambient temperatures but at the same developmental stage. Diurnal pistil measurements included carbohydrate balance, glutathione reductase (GR; EC 1.8.1.7), soluble protein, superoxide dismutase (SOD; EC 1.15.1.1), NADPH oxidase (NOX; EC 1.6.3.1), adenosine triphosphate (ATP), and water-soluble calcium. Soluble carbohydrate levels in cotton pistils were as much as 67.5% lower under high temperature conditions (34.6 °C maximum air temperature; August 4, 2009) than under cooler conditions (29.9 °C maximum air temperature; August 14, 2009). Regression analysis revealed that pollen tube growth rates were highly correlated with the soluble carbohydrate content of the pistil during pollen tube growth (r² = 0.932). Higher ambient temperature conditions on August 4 increased GR activity in the pistil only during periods not associated with in vivo pollen tube growth; pistil protein content declined earlier in the day under high temperatures; SOD and NOX were unaffected by either sample date or time of day; pistil ATP and water soluble calcium were unaffected by the warmer temperatures. We conclude that moderate heat stress significantly alters diurnal carbohydrate balance in the pistil and suggest that pollen tube growth rate through the style may be limited by soluble carbohydrate

  9. Impact of volcanic stratospheric aerosols on diurnal temperature range in Europe over the past 200 years: Observations versus model simulations

    NASA Astrophysics Data System (ADS)

    Auchmann, Renate; Arfeuille, Florian; Wegmann, Martin; Franke, Jörg; Barriendos, Mariano; Prohom, Marc; Sanchez-Lorenzo, Arturo; Bhend, Jonas; Wild, Martin; Folini, Doris; Å těpánek, Petr; Brönnimann, Stefan

    2013-08-01

    analyze the impact of stratospheric volcanic aerosols on the diurnal temperature range (DTR) over Europe using long-term subdaily station records. We compare the results with a 28-member ensemble of European Centre/Hamburg version 5.4 (ECHAM5.4) general circulation model simulations. Eight stratospheric volcanic eruptions during the instrumental period are investigated. Seasonal all- and clear-sky DTR anomalies are compared with contemporary (approximately 20 year) reference periods. Clear sky is used to eliminate cloud effects and better estimate the signal from the direct radiative forcing of the volcanic aerosols. We do not find a consistent effect of stratospheric aerosols on all-sky DTR. For clear skies, we find average DTR anomalies of -0.08°C (-0.13°C) in the observations (in the model), with the largest effect in the second winter after the eruption. Although the clear-sky DTR anomalies from different stations, volcanic eruptions, and seasons show heterogeneous signals in terms of order of magnitude and sign, the significantly negative DTR anomalies (e.g., after the Tambora eruption) are qualitatively consistent with other studies. Referencing with clear-sky DTR anomalies to the radiative forcing from stratospheric volcanic eruptions, we find the resulting sensitivity to be of the same order of magnitude as previously published estimates for tropospheric aerosols during the so-called "global dimming" period (i.e., 1950s to 1980s). Analyzing cloud cover changes after volcanic eruptions reveals an increase in clear-sky days in both data sets. Quantifying the impact of stratospheric volcanic eruptions on clear-sky DTR over Europe provides valuable information for the study of the radiative effect of stratospheric aerosols and for geo-engineering purposes.

  10. Diurnal patterns of blowing sand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diurnal pattern of blowing sand results from a complex process that involves an interaction between solar heating, thermal instability, atmospheric turbulence, wind strength, and surface threshold conditions. During the day, solar heating produces thermal instability, which enhances the convect...

  11. Annual Climatology of the Diurnal Cycle on the Canadian Prairies

    NASA Astrophysics Data System (ADS)

    Betts, Alan; Tawfik, Ahmed

    2016-01-01

    We show the annual climatology of the diurnal cycle, stratified by opaque cloud, using the full hourly resolution of the Canadian Prairie data. The opaque cloud field itself has distinct cold and warm season diurnal climatologies; with a near-sunrise peak of cloud in the cold season and an early afternoon peak in the warm season. There are two primary climate states on the Canadian Prairies, separated by the freezing point of water, because a reflective surface snow cover acts as a climate switch. Both cold and warm season climatologies can be seen in the transition months of November, March and April with a large difference in mean temperature. In the cold season with snow, the diurnal ranges of temperature and relative humidity increase quasi-linearly with decreasing cloud, and increase from December to March with increased solar forcing. The warm season months, April to September, show a homogeneous coupling to the cloud cover, and a diurnal cycle of temperature and humidity that depends only on net longwave. Our improved representation of the diurnal cycle shows that the warm season coupling between diurnal temperature range and net longwave is weakly quadratic through the origin, rather than the linear coupling shown in earlier papers. We calculate the conceptually important 24-h imbalances of temperature and relative humidity (and other thermodynamic variables) as a function of opaque cloud cover. In the warm season under nearly clear skies, there is a warming of +2oC and a drying of -6% over the 24-h cycle, which is about 12% of their diurnal ranges. We summarize results on conserved variable diagrams and explore the impact of surface windspeed on the diurnal cycle in the cold and warm seasons. In all months, the fall in minimum temperature is reduced with increasing windspeed, which reduces the diurnal temperature range. In July and August, there is an increase of afternoon maximum temperature and humidity at low windspeeds, and a corresponding rise in

  12. Assimilating Satellite SST Observations into a Diurnal Cycle Model

    NASA Astrophysics Data System (ADS)

    Pimentel, S.; Haines, K.; Nichols, N. K.

    2006-12-01

    The wealth of satellite sea surface temperature (SST) data now available opens the possibility of large improvements in SST estimation. However the use of such data is not straight forward; a major difficulty in assimilating satellite observations is that they represent a near surface temperature, whereas in ocean models the top level represents the temperature at a greater depth. During the day, under favourable conditions of clear skies and calm winds, the near surface temperature is often seen to have a diurnal cycle that is picked up in satellite observations. Current ocean models do not have the vertical or temporal resolution to adequately represent this daytime warming. The usual approach is to discard daytime observations as they are considered diurnally `corrupted'. A new assimilation technique is developed here that assimilates observations into a diurnal cycle model. The diurnal cycle of SSTs are modelled using a 1-D mixed layer model with fine near surface resolution and 6 hourly forcing from NWP analyses. The accuracy of the SST estimates are hampered by uncertainties in the forcing data. The extent of diurnal SST warming at a particular location and time is predominately governed by a non-linear response to cloud cover and sea surface wind speeds which greatly affect the air-sea fluxes. The method proposed here combines infrared and microwave SST satellite observations in order to derive corrections to the cloud cover and wind speed values over the day. By adjusting the forcing, SST estimation and air-sea fluxes should be improved and are at least more consistent with each other. This new technique for assimilating SST data can be considered a tool for producing more accurate diurnal warming estimates.

  13. Diurnal variations of energetic particle radiation at the surface of Mars as observed by the Mars Science Laboratory Radiation Assessment Detector

    NASA Astrophysics Data System (ADS)

    Rafkin, Scot C. R.; Zeitlin, Cary; Ehresmann, Bent; Hassler, Don; Guo, Jingnan; Köhler, Jan; Wimmer-Schweingruber, Robert; Gomez-Elvira, Javier; Harri, Ari-Matti; Kahanpää, Henrik; Brinza, David E.; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Söenke; Martin, Cesar; Reitz, Güenther; Cucinotta, Francis A.; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A.; Posner, Arik

    2014-06-01

    The Radiation Assessment Detector onboard the Mars Science Laboratory rover Curiosity is detecting the energetic particle radiation at the surface of Mars. Data collected over the first 350 Martian days of the nominal surface mission show a pronounced diurnal cycle in both the total dose rate and the neutral particle count rate. The diurnal variations detected by the Radiation Assessment Detector were neither anticipated nor previously considered in the literature. These cyclic variations in dose rate and count rate are shown to be the result of changes in atmospheric column mass driven by the atmospheric thermal tide that is characterized through pressure measurements obtained by the Rover Environmental Monitoring Station, also onboard the rover. In addition to bulk changes in the radiation environment, changes in atmospheric shielding forced by the thermal tide are shown to disproportionately affect heavy ions compared to H and He nuclei.

  14. Ozone-Temperature Diurnal and Longer Term Correlations, in the Lower Thermosphere, Mesosphere and Stratosphere, Based on Measurements from SABER on TIMED

    NASA Technical Reports Server (NTRS)

    Huang, Frank T.; Mayr, Hans G.; Russell, James M., III; Mlynczak, Martin G.

    2012-01-01

    The analysis of mutual ozone-temperature variations can provide useful information on their interdependencies relative to the photochemistry and dynamics governing their behavior. Previous studies have mostly been based on satellite measurements taken at a fixed local time in the stratosphere and lower mesosphere. For these data, it is shown that the zonal mean ozone amounts and temperatures in the lower stratosphere are mostly positively correlated, while they are mostly negatively correlated in the upper stratosphere and in the lower mesosphere. The negative correlation, due to the dependence of photochemical reaction rates on temperature, indicates that ozone photochemistry is more important than dynamics in determining the ozone amounts. In this study, we provide new results by extending the analysis to include diurnal variations over 24 hrs of local time, and to larger spatial regimes, to include the upper mesosphere and lower thermosphere (MLT). The results are based on measurements by the SABER instrument on the TIMED satellite. For mean variations (i.e., averages over local time and longitude) in the MLT, our results show that there is a sharp reversal in the correlation near 80 km altitude, above which the ozone mixing ratio and temperature are mostly positively correlated, while they are mostly negatively correlated below 80 km. This is consistent with the view that above -80 km, effects due to dynamics are more important compared to photochemistry. For diurnal variations, both the ozone and temperature show phase progressions in local time, as a function of altitude and latitude. For temperature, the phase progression is as expected, as they represent migrating tides. For day time ozone, we also find regular phase progression in local time over the whole altitude range of our analysis, 25 to 105 km, at least for low latitudes. This was not previously known, although phase progressions had been noted by us and by others at lower altitudes. For diurnal

  15. The international surface temperature initiative

    NASA Astrophysics Data System (ADS)

    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

  16. Effects of Mild Water Stress and Diurnal Changes in Temperature and Humidity on the Stable Oxygen and Hydrogen Isotopic Composition of Leaf Water in Cornus stolonifera L. 1

    PubMed Central

    Flanagan, Lawrence B.; Ehleringer, James R.

    1991-01-01

    In this paper we make comparisons between the observed stable isotopic composition of leaf water and the predictions of the Craig-Gordon model of isotopic enrichment when plants (Cornus stolonifera L.) were exposed to natural, diurnal changes in temperature and humidity in a glasshouse. In addition, we determined the effects of mild water stress on the isotopic composition of leaf water. The model predicted different patterns of diurnal change for the oxygen and hydrogen isotopic composition of leaf water. The observed leaf water isotopic composition followed qualitatively similar patterns of diurnal change to those predicted by the model. At midday, however, the model always predicted a higher degree of heavy isotope enrichment than was actually observed in leaves. There was no effect of mild water stress on the hydrogen isotopic composition of leaf water. For the oxygen isotopic composition of leaf water, there was either no significant difference between control and water-stressed plants or the stressed plants had lower δ18O values, despite the enriched stem water isotopic composition observed for the stressed plants. PMID:16668385

  17. Cumulus moistening, the diurnal cycle, and large-scale tropical dynamics

    NASA Astrophysics Data System (ADS)

    Ruppert, James H., Jr.

    Observations and modeling techniques are employed to diagnose the importance of the diurnal cycle in large-scale tropical climate. In the first part of the study, soundings, radar, and surface flux measurements collected in the Indian Ocean DYNAMO experiment (Dynamics of the Madden--Julian Oscillation, or MJO) are employed to study MJO convective onset. According to these observations, MJO onset takes place as follows: moistening of the low--midtroposphere is accomplished by cumuliform clouds that deepen as the drying by large-scale subsidence and horizontal advection simultaneously wane. This relaxing of subsidence is tied to decreasing column radiative cooling, which links back to the evolving cloud population. A new finding from these observations is the high degree to which the diurnal cycle linked to air-sea and radiative fluxes invigorates clouds and drives column moistening each day. This diurnally modulated cloud field exhibits pronounced mesoscale organization in the form of open cells and horizontal convective rolls. Based on these findings, it is hypothesized that the diurnal cycle and mesoscale cloud organization represent two manners in which local convective processes promote more vigorous day-to-day tropospheric moistening than would otherwise occur. A suite of model tests are carried out in the second part of the study to 1) test the hypothesis that the diurnal cycle drives moistening on longer timescales, and 2) better understand the relative roles of diurnally varying sea surface temperature (SST) and direct atmospheric radiative heating in the diurnal cycle of convection. Moist convection is explicitly represented in the model, the diurnal cycle of SST is prescribed, and cloud-interactive radiation is simulated with a diurnal cycle in shortwave heating. The large-scale dynamics are parameterized using the spectral weak temperature gradient (WTG) technique recently introduced by Herman and Raymond. In this scheme, external (i.e., large

  18. Tides in the Mesopause Region over Fort Collins, CO (41N, 105W) Based on Lidar Temperature Observations Covering Full Diurnal Cycles

    NASA Astrophysics Data System (ADS)

    She, C. Y.; Chen, S.; Hu, Z.; Williams, B. P.; Krueger, D. A.; Hagan, M. E.

    2001-05-01

    The sodium lidar at Colorado State Univeristy has obtained eighteen sets of 24-hr continuous temperature observations covering a full diurnal cycle distributed throughout the year for 82-102km altitude. These have been analyzed to reveal the seasonal mean amplitude and phase of oscillations with 24, 12, 8,and 6 hour periods. The diurnal and semidiurnal phases typically show clear downward phase propagation, while the ter-dirunal and quad-diurnal components exhibit small amplitudes and disorganized phases as a function of altitude. A comparison of the amplitudes and phases of the diurnal and semidiurnal components with the predictions of the Global-Scale Wave Model showed good general agreement, although better in some seasons than others, suggesting that global-scale migrating tides are the main cause of these oscillations. There is significant variability, however, in the 24 and 12 hr oscillations deduced from the individual 24-hr campaigns within each season. This is most notable in the amplitudes which vary by large factors (amplitudes range from 2K to 20K), even when the corresponding phases are stable to within a few hours, suggesting a modulation of the global migrating tide. This could be caused by time variation in a number of things: the local small-scale wave field, the source stength for global migrating or nonmigrating tide, or changes in the lower atmosphere winds that lead to filtering of any of these waves. It is hoped that future observations that add zonal and meridional wind measurements to the current temperaure measurements with the same durnal and altitude coverage will help clarify the causes of this intra-seasonal variability as well as help resolve the remaining seasonal-average differences between observations and models.

  19. DHC: a diurnal heat capacity program for microcomputers

    SciTech Connect

    Balcomb, J.D.

    1985-01-01

    A computer program has been developed that can predict the temperature swing in direct gain passive solar buildings. The diurnal heat capacity (DHC) program calculates the DHC for any combination of homogeneous or layered surfaces using closed-form harmonic solutions to the heat diffusion equation. The theory is described, a Basic program listing is provided, and an example solution printout is given.

  20. Estimation of Sea Surface Temperature (SST) Using Marine Seismic Data

    NASA Astrophysics Data System (ADS)

    Sinha, Satish Kumar; Dewangan, Pawan; Sain, Kalachand

    2016-04-01

    Not much attention is given to direct wave arrivals in marine seismic data that are acquired for petroleum exploration and prospecting. These direct arrivals are usually muted out in routine seismic data processing. In the present study, we process these direct arrivals to accurately estimate soundspeed in near-surface seawater and invert for sea surface temperature. The established empirical equation describing the relationships among temperature, salinity, pressure and soundspeed is used for the inversion. We also discuss processing techniques, such as first-break picking and cross-correlation for the estimation of soundspeed, that are well known among petroleum-industry geophysicists. The accuracy of the methods is directly linked to the data quality and signal processing. The novelty in our approach is in the data conditioning, which consists essentially of spectral balancing based on a wavelet transform that compensates for spherical spreading and increases the signal-to-noise ( S/ N) ratio. The 2D seismic data used in this paper are from the offshore Krishna-Godavari Basin east of India. We observe a significantly higher soundspeed of 1545 m/s for near-surface water than the commonly used value of ~1500 m/s. The estimated temperature (from velocity) is about 30 °C. Interestingly, the estimated temperature matches well with the temperature recorded in the CTD profile acquired in the study area during the month of May, the month corresponding to the acquisition of seismic data. Furthermore, the estimated temperatures during different times of data acquisition correlate well with the expected diurnal variation in temperature.

  1. Radiative surface temperatures of the burned and unburned areas in a tallgrass prairie

    NASA Technical Reports Server (NTRS)

    Asrar, G.; Harris, T. R.; Lapitan, R. L.; Cooper, D. I.

    1988-01-01

    This study was conducted in a natural tallgrass prairie area in the Flint Hills of Kansas. The objective was to evaluate the surface radiative temperatures of burned and unburned treatments of the grassland as a means of delineating the areas covered by each treatment. Burning is used to remove the senescent vegetation resulting from the previous year's growth. Surface temperatures were obtained in situ and by an airborne scanner. Burned and unburned grass canopies had distinctly different diurnal surface radiative temperatures. Measurements of surface energy balance components revealed a difference in partitioning of the available energy between the two canopies, which resulted in the difference in their measured surface temperatures. The magnitude of this difference is dependent on the time of measurements and topographic conditions.

  2. Impact of urbanization and land-use/land-cover change on diurnal temperature range: a case study of tropical urban airshed of India using remote sensing data.

    PubMed

    Mohan, Manju; Kandya, Anurag

    2015-02-15

    Diurnal temperature range (DTR) is an important climate change index. Its knowledge is important to a range of issues and themes in earth sciences central to urban climatology and human-environment interactions. The present study investigates the effect of urbanization on the land surface temperature (LST) based DTR. This study presents spatial and temporal variations of satellite based estimates of annually averaged DTR over megacity Delhi, the capital of India, which are shown for a period of 11 years during 2001-2011 and analyzes this with regard to its land-use/land-cover (LU/LC) changes and population growth. Delhi which witnessed massive urbanization in terms of population growth (decadal growth rate of Delhi during 2001-2011 was 20.96%) and major transformations in the LU/LC (built-up area crossed more than 53%) are experiencing severity in its micro and macroclimate. There was a consistent increase in the areas experiencing DTR below 11°C which typically resembled the 'urban class' viz. from 26.4% in the year 2001 to 65.3% in the year 2011 and subsequently the DTR of entire Delhi which was 12.48°C in the year 2001 gradually reduced to 10.34°C in the year 2011, exhibiting a significant decreasing trend. Rapidly urbanizing areas like Rohini, Dwarka, Vasant Kunj, Kaushambi, Khanjhawala Village, IIT, Safdarjung Airport, etc. registered a significant decreasing trend in the DTR. In the background of the converging DTR, which was primarily due to the increase in the minimum temperatures, a grim situation in terms of potentially net increase in the heat-related mortality rate especially for the young children below 15years of age is envisaged for Delhi. Considering the earlier findings that the level of risk of death remained the highest and longest for Delhi, in comparison to megacities like Sao Paulo and London, the study calls for strong and urgent heat island mitigation measures. PMID:25437763

  3. Direct observations of shortwave aerosol radiative forcing at surface and its diurnal variation during the Asian dry season at southwest Indian peninsula

    NASA Astrophysics Data System (ADS)

    Mishra, Manoj Kumar; Rajeev, K.

    2016-08-01

    The Arabian Sea witnesses consistent occurrence of a large-scale aerosol plume transported by the northerlies from the Asian region during the dry season (December-April). This paper presents direct observations of the diurnal variation (and dependence on solar zenith angle, SZA) of instantaneous aerosol direct radiative forcing efficiency (IADRFE) and aerosol direct radiative forcing (ADRF) at surface during the period from December to March of 2010-2013 at Thiruvananthapuram (8.5°N, 77°E), an Indian peninsular station adjoining the Arabian Sea coast, which resides well within this aerosol plume. Magnitude of the IADRFE increases with SZA from -75 ± 20 W m-2 τ 500 -1 at SZA of ~80° to attain a peak value of -170 ± 30 W m-2 τ 500 -1 at SZA ~60° in March (~3 h before and after the local noon). Absolute magnitudes and SZA dependence of the observed seasonal mean IADRFE are in agreement (within 16 % of the absolute magnitudes) with those estimated using radiation transfer computations employing an aerosol model with visible band single-scattering albedo of ~0.90 ± 0.03. Observed values of the diurnal mean aerosol radiative forcing efficiency (ADRFE) averaged during the season (December-March) vary between -71 and -76.5 W m-2 τ 500 -1 , which is in agreement with the model estimate of -71 W m-2 τ 500 -1 . The present observations show that the seasonal mean ADRF at surface (-25 to -28 W m-2) is about 10 % of the diurnal mean downwelling shortwave flux reaching the surface (in the absence of aerosols) during dry season at this location, indicating the major role of aerosols in regulating surface energetics.

  4. Direct observations of shortwave aerosol radiative forcing at surface and its diurnal variation during the Asian dry season at southwest Indian peninsula

    NASA Astrophysics Data System (ADS)

    Mishra, Manoj Kumar; Rajeev, K.

    2016-01-01

    The Arabian Sea witnesses consistent occurrence of a large-scale aerosol plume transported by the northerlies from the Asian region during the dry season (December-April). This paper presents direct observations of the diurnal variation (and dependence on solar zenith angle, SZA) of instantaneous aerosol direct radiative forcing efficiency (IADRFE) and aerosol direct radiative forcing (ADRF) at surface during the period from December to March of 2010-2013 at Thiruvananthapuram (8.5°N, 77°E), an Indian peninsular station adjoining the Arabian Sea coast, which resides well within this aerosol plume. Magnitude of the IADRFE increases with SZA from -75 ± 20 W m-2 τ {500/-1} at SZA of ~80° to attain a peak value of -170 ± 30 W m-2 τ {500/-1} at SZA ~60° in March (~3 h before and after the local noon). Absolute magnitudes and SZA dependence of the observed seasonal mean IADRFE are in agreement (within 16 % of the absolute magnitudes) with those estimated using radiation transfer computations employing an aerosol model with visible band single-scattering albedo of ~0.90 ± 0.03. Observed values of the diurnal mean aerosol radiative forcing efficiency (ADRFE) averaged during the season (December-March) vary between -71 and -76.5 W m-2 τ {500/-1}, which is in agreement with the model estimate of -71 W m-2 τ {500/-1}. The present observations show that the seasonal mean ADRF at surface (-25 to -28 W m-2) is about 10 % of the diurnal mean downwelling shortwave flux reaching the surface (in the absence of aerosols) during dry season at this location, indicating the major role of aerosols in regulating surface energetics.

  5. Improving the Accuracy of Satellite Sea Surface Temperature Measurements by Explicitly Accounting for the Bulk-Skin Temperature Difference

    NASA Technical Reports Server (NTRS)

    Castro, Sandra L.; Emery, William J.

    2002-01-01

    The focus of this research was to determine whether the accuracy of satellite measurements of sea surface temperature (SST) could be improved by explicitly accounting for the complex temperature gradients at the surface of the ocean associated with the cool skin and diurnal warm layers. To achieve this goal, work centered on the development and deployment of low-cost infrared radiometers to enable the direct validation of satellite measurements of skin temperature. During this one year grant, design and construction of an improved infrared radiometer was completed and testing was initiated. In addition, development of an improved parametric model for the bulk-skin temperature difference was completed using data from the previous version of the radiometer. This model will comprise a key component of an improved procedure for estimating the bulk SST from satellites. The results comprised a significant portion of the Ph.D. thesis completed by one graduate student and they are currently being converted into a journal publication.

  6. Microclimatic Temperature Relationships over Different Surfaces.

    ERIC Educational Resources Information Center

    Williams, Thomas B.

    1991-01-01

    Describes a study of temperature variations over different surfaces in an urban campus setting. Explains that researchers sampled temperatures over grass, bare soil, gravel, concrete, and blacktop. Reports that grassy areas registered the highest morning temperatures and lowest afternoon temperatures. (SG)

  7. Near-surface variability of temperature and salinity in the near-tropical ocean: Observations from profiling floats

    NASA Astrophysics Data System (ADS)

    Anderson, Jessica E.; Riser, Stephen C.

    2014-11-01

    Upper ocean measurements of temperature and salinity obtained from profiling floats equipped with auxiliary surface temperature and salinity sensors (STS) are presented. Using these instruments, high vertical resolution (10 cm) measurements in the near-surface layer were acquired to within 20 cm of the sea surface, allowing for an examination of the ocean's near-surface structure and variability not usually possible. We examine the data from 62 Argo-type floats equipped with STS units deployed in the Pacific, Atlantic, and Indian Oceans. The vertical variability of temperature and salinity in the near-surface layer is characterized for each of these regions. While observations show the upper 4 m of the ocean are well mixed most of the time, this homogeneity is interrupted by significant and often short-lived warming/cooling and freshening events. In addition to the presence of barrier layers, a strong diurnal signal in temperature is observed, with salinity exhibiting somewhat weaker diurnal variations. The magnitude of the upper ocean diurnal cycle in temperature and salinity is largest in areas with light winds and heavy precipitation and was found to decay rapidly with depth (˜50% over the top 2 m). Storm events, validated from meteorological data collected from nearby TAO moorings and the Tropical Rainfall Measuring Mission (TRMM) satellite, show downward mixing of rainfall-derived freshwater to 10 m depth over only a few hours. Turner angle calculations show instability following these events.

  8. Estimation of Surface Air Temperature from MODIS 1km Resolution Land Surface Temperature Over Northern China

    NASA Technical Reports Server (NTRS)

    Shen, Suhung; Leptoukh, Gregory G.; Gerasimov, Irina

    2010-01-01

    Surface air temperature is a critical variable to describe the energy and water cycle of the Earth-atmosphere system and is a key input element for hydrology and land surface models. It is a very important variable in agricultural applications and climate change studies. This is a preliminary study to examine statistical relationships between ground meteorological station measured surface daily maximum/minimum air temperature and satellite remotely sensed land surface temperature from MODIS over the dry and semiarid regions of northern China. Studies were conducted for both MODIS-Terra and MODIS-Aqua by using year 2009 data. Results indicate that the relationships between surface air temperature and remotely sensed land surface temperature are statistically significant. The relationships between the maximum air temperature and daytime land surface temperature depends significantly on land surface types and vegetation index, but the minimum air temperature and nighttime land surface temperature has little dependence on the surface conditions. Based on linear regression relationship between surface air temperature and MODIS land surface temperature, surface maximum and minimum air temperatures are estimated from 1km MODIS land surface temperature under clear sky conditions. The statistical errors (sigma) of the estimated daily maximum (minimum) air temperature is about 3.8 C(3.7 C).

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

    SciTech Connect

    Nelson, Caleb T.; Overzet, Lawrence J.; Goeckner, Matthew J.

    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.

  10. Unexpected and Unexplained Surface Temperature Variations on Mimas

    NASA Astrophysics Data System (ADS)

    Howett, C.; Spencer, J. R.; Pearl, J. C.; Hurford, T. A.; Segura, M.; Cassini Cirs Team

    2010-12-01

    could cause surface defects. For this process to also explain the observed temperature differences it would have to affect the surface’s thermal inertia to a depth comparable to the diurnal thermal skin-depth (~0.5 cm). However, whether the formation of the giant Herschel crater (which lies in the middle of the observed portion of the cold region) contributed to the observed temperature anomaly or if electron bombardment alone is able to explain the thermal anomaly is currently unknown. Future CIRS observations should be able to map the full spatial extent of the thermal anomaly and clarify whether it is centered on (and thus likely related to) Herschel, or is centered on the trailing hemisphere and thus likely to be related to the observed color anomaly.

  11. Radiometric surface temperature components for row crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature is a boundary condition often used in assessing soil moisture status and energy exchange from the soil-vegetation-atmosphere interface. For row crops having incomplete canopy cover, the radiometric surface temperature is a composite of sunlit and shaded vegetation and substr...

  12. New satellite record of sea surface temperature

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-02-01

    Sea surface temperature is one of the key variables scientists track in studying climate changes; it is also important to meteorology and oceanography. Merchant et al. describe a new 20-year record of sea surface temperature. The record was created using infrared imagery from the Along-Track Scanning Radiometers (ATSR) as part of the ATSR Reprocessing for Climate (ARC) project.

  13. Assimilation of Surface Temperature in Land Surface Models

    NASA Technical Reports Server (NTRS)

    Lakshmi, Venkataraman

    1998-01-01

    Hydrological models have been calibrated and validated using catchment streamflows. However, using a point measurement does not guarantee correct spatial distribution of model computed heat fluxes, soil moisture and surface temperatures. With the advent of satellites in the late 70s, surface temperature is being measured two to four times a day from various satellite sensors and different platforms. The purpose of this paper is to demonstrate use of satellite surface temperature in (a) validation of model computed surface temperatures and (b) assimilation of satellite surface temperatures into a hydrological model in order to improve the prediction accuracy of soil moistures and heat fluxes. The assimilation is carried out by comparing the satellite and the model produced surface temperatures and setting the "true"temperature midway between the two values. Based on this "true" surface temperature, the physical relationships of water and energy balance are used to reset the other variables. This is a case of nudging the water and energy balance variables so that they are consistent with each other and the true" surface temperature. The potential of this assimilation scheme is demonstrated in the form of various experiments that highlight the various aspects. This study is carried over the Red-Arkansas basin in the southern United States (a 5 deg X 10 deg area) over a time period of a year (August 1987 - July 1988). The land surface hydrological model is run on an hourly time step. The results show that satellite surface temperature assimilation improves the accuracy of the computed surface soil moisture remarkably.

  14. Titan Surface Temperatures from Cassini CIRS

    NASA Technical Reports Server (NTRS)

    Jennings, Donald E.; Flasar, F.M.; Kundle, V.G.; Samuelson, R.E.; Pearl, J.C.; Nixon, C.A.; Carlson, R.C.; Mamoutkine, A.A.; Brasunas, J.C.; Guandique, E.; Achterberg, R.K.; Bjoraker, M.H.; Romani, P.N.; Segura, M.E.; Albright, S.A.; Elliott, M.H.; Tingley, J.S.; Calcutt, S.; Coustenis, A.; Bezard, B.; Courtin, R.

    2008-01-01

    Thermal radiation from the surface of Titan reaches space through a spectral window at 19-microns wavelength. After removing the effects of the atmosphere, measurement of this radiance gives the brightness temperature of the surface. The Composite Infrared Spectrometer (CIRS) has made such measurements during the Cassini prime mission. These observations cover a wide range of emission angles, thereby constraining the contributions from atmospheric radiance and opacity. With the more complete latitude coverage and much larger dataset, we have been able to improve upon the original results from Voyager IRIS. CIRS measures an equatorial surface brightness temperature, averaged over longitude, of 93.7 +/- 0.6 K. This agrees with the HASI temperature at the Huygens landing site. The latitude dependence of surface brightness temperature exhibits an approximately 2 K decrease toward the South Pole and 3 K decrease toward the North Pole. The lower surface temperatures seen at high latitudes are consistent with conditions expected for lake formation.

  15. Impact of land use and precipitation changes on surface temperature trends in Argentina

    NASA Astrophysics Data System (ADS)

    NuñEz, Mario N.; Ciapessoni, HéCtor H.; Rolla, Alfredo; Kalnay, Eugenia; Cai, Ming

    2008-03-01

    The "observation minus reanalysis" (OMR) method has been used to estimate the impact of changes in land use (including urbanization and agricultural practices such as irrigation) by computing the difference between the trends of the surface observations (which reflect all the sources of climate forcing, including surface effects) and the NCEP/NCAR reanalysis (which only contains the forcings influencing the assimilated atmospheric trends). In this paper we apply the OMR method to surface stations in Argentina for the period 1961-2000. In contrast to most other land areas, over most of Argentina there has been net cooling, not warming (about -0.04°C/decade). Observations also show a very strong decrease in the diurnal temperature range north of 40°S. This is associated with an observed strong reduction in the maximum temperature (-0.12°C/decade) together with a weak warming trend in the minimum temperature (0.05°C/decade). The OMR trends show a warming contribution to the mean temperature (+0.07°C/decade) and a decrease in diurnal temperature range (-0.08°C/decade), especially strong in the areas where the observed precipitation has increased the most and where, as a consequence, there has been an exponential increase of soy production in the last decade. The increase in precipitation is apparently associated with an increase in the moisture transport from the Amazons to northern Argentina by the low-level jet.

  16. Effect of surface temperature on microparticle-surface adhesion

    NASA Astrophysics Data System (ADS)

    Vallabh, Chaitanya Krishna Prasad; Stephens, James D.; Cetinkaya, Cetin

    2015-07-01

    The effect of surface temperature on the adhesion properties of the bond between a substrate and a single micro-particle is investigated in a non-contact/non-invasive manner by monitoring the rolling/rocking motion dynamics of acoustically excited single microparticles. In the current work, a set of experiments were performed to observe the change in the rocking resonance frequency of the particles with the change of surface temperature. At various substrate surface temperature levels, the work-of-adhesion values of the surface-particle bond are evaluated from the resonance frequencies of the rocking motion of a set of microparticles driven by an orthogonal ultrasonic surface acoustic wave field. The dependence of adhesion bonds of a microparticle and the substrate on the surface temperature has been clearly demonstrated by the performed experiments. It was also observed and noted that the relative humidity plays a vital role in the rolling behavior of particles.

  17. Maintenance of Coastal Surface Blooms by Surface Temperature Stratification and Wind Drift

    PubMed Central

    Ruiz-de la Torre, Mary Carmen; Maske, Helmut; Ochoa, José; Almeda-Jauregui, César O.

    2013-01-01

    Algae blooms are an increasingly recurrent phenomenon of potentially socio-economic impact in coastal waters globally and in the coastal upwelling region off northern Baja California, Mexico. In coastal upwelling areas the diurnal wind pattern is directed towards the coast during the day. We regularly found positive Near Surface Temperature Stratification (NSTS), the resulting density stratification is expected to reduce the frictional coupling of the surface layer from deeper waters and allow for its more efficient wind transport. We propose that the net transport of the top layer of approximately 2.7 kilometers per day towards the coast helps maintain surface blooms of slow growing dinoflagellate such as Lingulodinium polyedrum. We measured: near surface stratification with a free-rising CTD profiler, trajectories of drifter buoys with attached thermographs, wind speed and direction, velocity profiles via an Acoustic Doppler Current Profiler, Chlorophyll and cell concentration from water samples and vertical migration using sediment traps. The ADCP and drifter data agree and show noticeable current shear within the first meters of the surface where temperature stratification and high cell densities of L. polyedrum were found during the day. Drifters with 1m depth drogue moved towards the shore, whereas drifters at 3 and 5 m depth showed trajectories parallel or away from shore. A small part of the surface population migrated down to the sea floor during night thus reducing horizontal dispersion. The persistent transport of the surface bloom population towards shore should help maintain the bloom in favorable environmental conditions with high nutrients, but also increasing the potential socioeconomic impact of the blooms. The coast wise transport is not limited to blooms but includes all dissolved and particulate constituents in surface waters. PMID:23593127

  18. Upscaling and downscaling of land surface fluxes with surface temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature (LST) is a key surface boundary condition that is significantly correlated to surface flux partitioning between latent and sensible heat. The spatial and temporal variation in LST is driven by radiation, wind, vegetation cover and roughness as well as soil moisture status ...

  19. The influence of surface characteristics on lapse rates and temperature profiles in areas of complex terrain

    NASA Astrophysics Data System (ADS)

    Pepin, N. C.; Pike, G.; Fower, D.; Schaefer, M.

    2012-12-01

    Temperatures near the ground are often decoupled from free-air equivalents, particularly in areas of complex relief and at high latitudes where cold air drainage occurs particularly when radiation balances become negative. This means that it is hard to predict spatial patterns of surface temperature in such regions. In this study several years of intensive field measurements in complex terrain in northern Finland (Kevo) and Sweden (Abisko) allow detailed examination of the interaction between land surface characteristics (including cryosphere), vegetation, and local/micro-climate in mountain basins. Temperature and vapour pressure were measured every 30 minutes for 5 years (2007-2012) at 60 sites at Kevo and for a winter season (September-June) at 52 sites in Abisko, ranging over 300/600 metres of elevation respectively. In Finland lapse rates vary considerably both seasonally and diurnally, the relative importance of seasonal and diurnal forcing changing throughout the year. The results show intense (up to +80 °C/km) and persistent inversion events during the winter months (NDJ) which are broken up by mechanical effects since there is no diurnal cycle. In the transition from winter into spring (FMA) these inversions still occur but increasing radiation imposes a diurnal pattern on their formation and destruction. As snow cover peaks in spring the interaction between surface albedo, land cover and radiation serves to amplify the diurnal cycle in lapse rates. Daytime lapse rates peak in spring because of an increase in albedo with elevation as dark trees give way to reflective snow. At night inversions rapidly reform. Summer lapse rates are modified (usually weakened) by the presence of open water at low elevations. In Abisko similar processes are shown to be at work, although since the valley system is more open and at a larger spatial scale, the range of lapse rate variability is slightly less and the influence of surface characteristics more subdued. Taken

  20. A diurnal study of lunar topography to determine regolith temperature contributions to the inference of hydrogen volatiles using epithermal neutrons from the Lunar Exploration Neutron Detector (LEND).

    NASA Astrophysics Data System (ADS)

    McClanahan, T. P.; Mitrofanov, I. G.; Boynton, W. V.; Chin, G.; Evans, L. G.; Starr, R. D.; Livengood, T. A.; Litvak, M. L.; Sanin, A. B.; Murray, J.; Parsons, A. M.; Su, J. J.; Bodnarik, J.; Harshman, K.; Sagdeev, R.

    2014-12-01

    In this research we investigate lunar volatiles in the Moon's southern latitudes under diurnal conditions using five years of accumulated epithermal neutron observations by the Lunar Reconnaissance Orbiter's Lunar Exploration Neutron Detector. The primary objective of this research is to determine the spatial extent and magnitude of a possible regolith temperature contribution to the Moon's epithermal leakage flux as a function of topography. Ongoing research has suggested that there exists a widespread preferential bias in hydrogen concentrations towards the Moon's poleward-facing slopes as evidenced by a localized 1-2% suppression of the lunar epithermal leakage flux relative to equivalent equator-facing slopes (McClahanan et al., Under Review 2014). Monte Carlo neutron modeling results by (Lawson et al., 2000; Little et al. 2002) found that the epithermal neutron leakage flux may be slightly enhanced ~1% with regolith temperature in lunar conditions. Contrasting temperature conditions on poleward-facing and equator-facing slopes may at least partially explain the observation of biased concentrations of hydrogen towards poleward-facing slopes. To isolate any temperature contribution, LEND night observations are mapped and correlated with temperature maps from LRO's Diviner radiometer and terrain and illumination models derived from the Lunar Observing Laser Altimeter. Night and day results are contrasted to illustrate both the magitude and latitude extent of putative temperature effects and spatial hydrogen distributions.

  1. Titan's Surface Temperatures Measured by Cassini CIRS

    NASA Technical Reports Server (NTRS)

    Jennings, Donald E.; Flasar, F. M.; Kundle, V. G.; Samuelson, R. E.; Pearl, J. C.; Nixon, C. A.; Carlson, R. C.; Mamoutkine, A. A.; Brasunas, J. C.; Guandique, E.; Arhterberg, R. K.; Bjoraker, G. L.; Romani, P. N.; Segura, M. E.; Albright, S. A.; Elliott, M. H.; Tingley, J. S.; Calcutt, S.; Coustenis, A.; Bezard, B.; Courtin, R.

    2008-01-01

    A large fraction of 19-micron thermal radiation from the surface of Titan reaches space through a spectral window of low atmospheric opacity. The emergent radiance, after removing the effect of the atmosphere, gives the brightness temperature of the surface. This atmospheric window is covered by the far-infrared channel of the Composite Infrared spectrometer1 (CIRS) on Cassini. In mapping Titan surface temperatures, CIRS is able to improve upon results of Voyager IRIS, by taking advantage of improved latitude coverage and a much larger dataset. Observations are from a wide range of emission angles and thereby provide constraints on the atmospheric opacity and radiance that are used to derive the surface temperature. CIRS finds an average equatorial surface brightness temperature of 93.7+/-0.6 K, virtually identical to the HASI temperature at the Huygens landing site. Mapping in latitude shows that the surface temperature decreases toward the poles by about 2 K in the south and 3 K in the north. This surface temperature distribution is consistent with the formation of lakes seen at high latitudes on Titan.

  2. Surface roughness effects on equilibrium temperature.

    NASA Technical Reports Server (NTRS)

    Houchens, A. F.; Hering, R. G.

    1972-01-01

    An analysis is presented for evaluation of equilibrium temperature distribution on radiatively adiabatic, adjoint planes which are uniformly irradiated by a collimated solar flux. The analysis employs a semigrey spectral model. Radiation properties for surface emitted radiation are obtained from the expressions of electromagnetic theory for smooth surfaces. Rough surface properties for solar radiation are given by the Beckmann bidirectional reflectance model. Numerical solutions to the governing equations yield equilibrium temperature distributions for a range of the influencing parameters. Surface roughness has little influence on equilibrium temperature for materials with high values for solar absorptance. However, for low or intermediate values of solar absorptance, roughness effects on the spatial distribution of reflected solar radiation can significantly alter equilibrium temperature particularly at surface elements where radiant interaction is small.

  3. Impact of an improved WRF-urban canopy model on diurnal air temperature simulation over northern Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Chuan-yao; Su, Chiung-Jui; Kusaka, Hiroyuki; Akimoto, Yuko; Sheng, Yang Fan; Huang, Chuan, Jr.

    2016-04-01

    This study evaluated the impact of urbanization over northern Taiwan using the Weather Research and Forecasting (WRF) model coupled with the Noah land-surface model and a modified Urban Canopy Model (WRF-UCM2D). In the original UCM coupled in WRF (WRF-UCM), when the land use in the model grid is identified as "urban", the urban fraction value is fixed. Similarly, the UCM assumes the distribution of anthropogenic heat (AH) to be constant. Such not only may lead to over- or underestimation of urban fraction and AH in urban and non-urban areas, spatial variation also affects the model-estimated temperature. To overcome the above-mentioned limitations and to improve the performance of the original UCM model, WRF-UCM is modified to consider the 2-D urban fraction and AH (WRF-UCM2D). The two models were found to have comparable temperature simulation performance for urban areas but large differences in simulated results were observed for non-urban, especially at nighttime. WRF-UCM2D yielded a higher correlation coefficient (R2) than WRF-UCM (0.72 vs. 0.48, respectively), while bias and RMSE achieved by WRF-UCM2D were both significantly smaller than those attained by WRF-UCM (0.27 and 1.27 vs. 1.12 and 1.89, respectively). In other words, the improved model not only enhanced correlation but also reduced bias and RMSE for the nighttime data of non-urban areas. WRF-UCM2D performed much better than WRF-UCM at non-urban stations with low urban fraction during nighttime. The improved simulation performance of WRF-UCM2D at non-urban areas is attributed to the energy exchange which enables efficient turbulence mixing at low urban fraction. The achievement of this study has a crucial implication for assessing the impacts of urbanization on air quality and regional climate.

  4. Reproducibility of summertime diurnal precipitation over northern Eurasia simulated by CMIP5 climate models

    NASA Astrophysics Data System (ADS)

    Hirota, N.; Takayabu, Y. N.

    2015-12-01

    Reproducibility of diurnal precipitation over northern Eurasia simulated by CMIP5 climate models in their historical runs were evaluated, in comparison with station data (NCDC-9813) and satellite data (GSMaP-V5). We first calculated diurnal cycles by averaging precipitation at each local solar time (LST) in June-July-August during 1981-2000 over the continent of northern Eurasia (0-180E, 45-90N). Then we examined occurrence time of maximum precipitation and a contribution of diurnally varying precipitation to the total precipitation.The contribution of diurnal precipitation was about 21% in both NCDC-9813 and GSMaP-V5. The maximum precipitation occurred at 18LST in NCDC-9813 but 16LST in GSMaP-V5, indicating some uncertainties even in the observational datasets. The diurnal contribution of the CMIP5 models varied largely from 11% to 62%, and their timing of the precipitation maximum ranged from 11LST to 20LST. Interestingly, the contribution and the timing had strong negative correlation of -0.65. The models with larger diurnal precipitation showed precipitation maximum earlier around noon. Next, we compared sensitivity of precipitation to surface temperature and tropospheric humidity between 5 models with large diurnal precipitation (LDMs) and 5 models with small diurnal precipitation (SDMs). Precipitation in LDMs showed high sensitivity to surface temperature, indicating its close relationship with local instability. On the other hand, synoptic disturbances were more active in SDMs with a dominant role of the large scale condensation, and precipitation in SDMs was more related with tropospheric moisture. Therefore, the relative importance of the local instability and the synoptic disturbances was suggested to be an important factor in determining the contribution and timing of the diurnal precipitation. Acknowledgment: This study is supported by Green Network of Excellence (GRENE) Program by the Ministry of Education, Culture, Sports, Science and Technology

  5. Titan's Surface Temperatures from Cassini CIRS

    NASA Technical Reports Server (NTRS)

    Jennings, Donald E.; Cottini, Valeria; Nixon, Conor A.

    2010-01-01

    The surface brightness temperature of Titan can be measured from Cassini through a spectral window at 19 microns where the atmosphere is low in opacity. The Composite Infrared Spectrometer (CIRS) on Cassini observes this wavelength in its far-infrared channel. Because the Cassini tour has provided global coverage and a range of viewing geometries, CIRS has been able to go beyond the earlier flyby results of Voyager IRIS Near the equator, CIRS measures the zonally-averaged surface brightness temperature to be 917 K, very close to the temperature found at the surface by Huygens. Latitude maps show that Titan's surface temperatures drop off by about 2 K toward the south and by about 3 K toward the north. This temperature distribution is consistent with Titan's late northern winter when the data were taken. As the seasons progress, CIRS is continuing to search for corresponding changes in the temperatures of the surface and lower atmosphere. CIRS is also extending global mapping to both latitude and longitude to look for correlations between surface temperatures and geological features.

  6. Sea surface temperature of the coastal zones of France

    NASA Technical Reports Server (NTRS)

    Deschamps, P. Y.; Crepon, M.; Monget, J. M.; Verger, F. (Principal Investigator); Frouin, R.; Cassanet, J.; Wald, L.

    1980-01-01

    The various thermal gradients in the coastal zones of France were mapped with regard to natural phenomena and man made thermal effluents. The mesoscale thermal features of the English Channel, the Bay of Biscay, and the northwestern Mediterranean Sea were also studied. The evolution of the thermal gradients generated by the main estuaries of the French coastal zones was investigated along with the modeling of diurnal heating of the sea surface and its influence on the oceanic surface layers.

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

    NASA Astrophysics Data System (ADS)

    Ackerley, Duncan; Dommenget, Dietmar

    2016-06-01

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

  8. A Preliminary Study of Surface Temperature Cold Bias in COAMPS

    SciTech Connect

    Chin, H-N S; Leach, M J; Sugiyama, G A; Aluzzi, F J

    2001-04-27

    It is well recognized that the model predictability is more or less hampered by the imperfect representations of atmospheric state and model physics. Therefore, it is a common problem for any numerical models to exhibit some sorts of biases in the prediction. In this study, the emphasis is focused on the cold bias of surface temperature forecast in Naval Research Laboratory's three-dimensional mesoscale model, COAMPS (Coupled Ocean/Atmosphere Mesoscale Prediction System). Based on the comparison with the ground station data, there were two types of ground temperature cold biases identified in LLNL (Lawrence Livermore National Laboratory) operational forecasts of COAMPS over the California and Nevada regions during the 1999 winter and the 2000 spring. The first type of cold bias appears at high elevation regions covered by snow, and its magnitude can be as large as 30 F - 40 F lower than observed. The second type of cold bias mainly exists in the snow-free clear-sky regions, where the surface temperature is above the freezing point, and its magnitude can be up to 5 F - 10 F lower than observed. These cold biases can affect the low-level stratification, and even the diurnal variation of winds in the mountain regions, and therefore impact the atmospheric dispersion forecast. The main objective of this study is to explore the causes of such cold bias, and to further the improvement of the forecast performance in COAMPS. A series of experiments are performed to gauge the sensitivity of the model forecast due to the physics changes and large-scale data with various horizontal and vertical resolutions.

  9. Urban aerosol effects on surface insolation and surface temperature

    NASA Astrophysics Data System (ADS)

    Jin, M.; Burian, S. J.; Remer, L. A.; Shepherd, M. J.

    2007-12-01

    Urban aerosol particulates may play a fundamental role in urban microclimates and city-generated mesoscale circulations via its effects on energy balance of the surface. Key questions that need to be addressed include: (1) How do these particles affect the amount of solar energy reaching the surface and resulting surface temperature? (2) Is the effect the same in all cities? and (3) How does it vary from city to city? Using NASA AERONET in-situ observations, a radiative transfer model, and a regional climate mode (MM5), we assess aerosol effects on surface insolation and surf ace temperature for dense urban-polluted regions. Two big cities, one in a developing country (Beijing, P.R. China) and another in developed country (New York City, USA), are selected for inter-comparison. The study reveals that aerosol effects on surface temperature depends largely on aerosols' optical and chemical properties as well as atmosphere and land surface conditions, such as humidity and land cover. Therefore, the actual magnitudes of aerosol effects differ from city to city. Aerosol measurements from AERONET show both average and extreme cases for aerosol impacts on surface insolation. In general, aerosols reduce surface insolation by 30Wm-2. Nevertheless, in extreme cases, such reduction can exceed 100 Wm-2. Consequently, this reduces surface skin temperature 2-10C in an urban environment.

  10. Satellite and Skin Layer Effects on the Accuracy of Sea Surface Temperature Measurements from the GOES Satellites

    NASA Technical Reports Server (NTRS)

    Wick, Gary A.; Bates, John J.; Scott, Donna J.

    2000-01-01

    The latest Geostationary Operational Environmental Satellites (GOES) have facilitated significant improvements in our ability to measure sea surface temperature (SST) from geostationary satellites. Nonetheless, difficulties associated with sensor calibration and oceanic near-surface temperature gradients affect the accuracy of the measurements and our ability to estimate and interpret the diurnal cycle of the bulk SST. Overall, measurements of SST from the GOES Imagers on the GOES 8-10 satellites are shown to have very small bias (less than 0.02 K) and rms differences of between 0.6 and 0.9 K relative to buoy observations. Separate consideration of individual measurement times, however, demonstrates systematic bias variations of over 0.6 K with measurement hour. These bias variations significantly affect both the amplitude and shape of estimates of the diurnal SST cycle. Modeled estimates of the temperature difference across the oceanic cool skin and diurnal thermocline show that bias variations up to 0.3 K can result from variability in the near-surface layer. Oceanic near-surface layer and known "satellite midnight" calibration effects, however, explain only a portion of the observed bias variations, suggesting other possible calibration concerns. Methods of explicitly incorporating skin layer and diurnal thermocline effects in satellite bulk SST measurements were explored in an effort to further improve the measurement accuracy. While the approaches contain more complete physics, they do not yet significantly improve the accuracy of bulk SST measurements due to remaining uncertainties in the temperature difference across the near-surface layer.

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

    NASA Astrophysics Data System (ADS)

    Meza, Amalia; Mendoza, Luciano; Bianchi, Clara

    2016-07-01

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

  12. Nonmigrating diurnal tides in the equatorial middle atmosphere

    SciTech Connect

    Lieberman, R.S.

    1992-01-01

    Data from the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) are used to analyze the diurnal tides in the middle atmosphere. A novel aspect of this study is the emphasis on the relative importance of the nonmigrating components. These modes display a high degree of temporal variability during the LIMS observing period, and contribute substantially to the diurnal signal in wind and temperature. Their observed vertical phase variations are variable; however there is evidence for upward energy propagation. It has long been hypothesized that nonmigrating tides are driven by the diurnally-varying zonally asymmetric tropospheric heating constituents. This premise is examined by employing a linear tidal model to simulate the response of the atmosphere to realistic tidal drives. These quantities are calculated from the NCAR Community Climate Model. The large-scale CCM2 diurnal surface pressure, OLR and hydrology are well simulated under July and January conditions. The CCM2 diurnal fields of short-wave radiative, convective and diffusive PBL heating are used as input to a linear tidal model with Newtonian cooling. This model successfully reproduces many observed features of the migrating and nonmigrating diurnal surface pressure tides at low latitudes. In the middle atmosphere, tropospheric solar heating is the dominant source of the migrating tide. The zonal means and eastward migrating wavenumber one components are also associated with radiative heating. The eastward migrating wavenumber three pattern is strongly linked to the dry and moist convective heating as well. The observed eastward migrating tides are harder to simulate, due in part to the failure of the linear model to incorporate the dissipative effects to which they are prone.

  13. Surface modification of high temperature iron alloys

    DOEpatents

    Park, Jong-Hee

    1995-01-01

    A method and article of manufacture of a coated iron based alloy. The method includes providing an iron based alloy substrate, depositing a silicon containing layer on the alloy surface while maintaining the alloy at a temperature of about 700.degree. C.-1200.degree. C. to diffuse silicon into the alloy surface and exposing the alloy surface to an ammonia atmosphere to form a silicon/oxygen/nitrogen containing protective layer on the iron based alloy.

  14. Surface modification of high temperature iron alloys

    DOEpatents

    Park, J.H.

    1995-06-06

    A method and article of manufacture of a coated iron based alloy are disclosed. The method includes providing an iron based alloy substrate, depositing a silicon containing layer on the alloy surface while maintaining the alloy at a temperature of about 700--1200 C to diffuse silicon into the alloy surface and exposing the alloy surface to an ammonia atmosphere to form a silicon/oxygen/nitrogen containing protective layer on the iron based alloy. 13 figs.

  15. Medium-scale surface temperature mission: MUST

    NASA Astrophysics Data System (ADS)

    Duthil, Philippe; Vidal, Alain; Dubet, Dominique

    1997-12-01

    The medium scale surface temperature (MUST) mission, studied in the frame of a European Commission (DG XII) contract, is a large swath (1200 Km), medium resolution (250 m) thermal infra-red imager mission devoted to retrieve the land surface temperature in order to serve various applications. These applications are firstly those concerned with the soil and vegetation water status (agriculture, irrigation and water resources management) as evapotranspiration and soil moisture can be inferred from surface temperature through relevant models. The other applications are either directly using the surface temperature (some frosts conditions assessment) or the air temperature that is itself derived from surface temperature extrapolation (urban heat island, some air frosts conditions). The project basically aimed to demonstrate the relevance and efficiency of the MUST mission products in the relevant application fields and to assess the economical benefits of the mission. Also in the course of the study the design of a medium resolution, large swath thermal imager, providing the appropriate performance required by the users while compact and affordable, was produced. Finally the operational implementation of the system and especially the ground segment was considered.

  16. Retrieving mesopause temperature and line-of-sight wind from full-diurnal-cycle Na lidar observations.

    PubMed

    Krueger, David A; She, Chiao-Yao; Yuan, Tao

    2015-11-10

    Narrowband Na lidar measurement of mesopause region temperatures were pioneered by Fricke and von Zahn in 1985, in 1990 by She et al. at Colorado State University (CSU), with upgrades to measure both temperature and wind in 1994, and under sunlit conditions in 1996 with 24 h continuous observational capability in 2002. This paper details the assumptions and procedures for the retrieval of mesopause region temperatures, line-of-sight winds, and sodium densities from day and night signals from the CSU narrowband Na lidar. The Hanle effect and the effect of the pulsed laser line shape function on the accuracy of temperature and LOS wind retrieval are also discussed. PMID:26560775

  17. Does diurnal temperature range influence seasonal suicide mortality? Assessment of daily data of the Helsinki metropolitan area from 1973 to 2010

    NASA Astrophysics Data System (ADS)

    Holopainen, Jari; Helama, Samuli; Partonen, Timo

    2014-08-01

    Several studies show a peak in suicide rates during springtime and suggest differences in the seasonal variation of suicides. However, the seasonal distribution of the temperature impact on suicide is less clear. This study investigated the relationship between diurnal temperature range (DTR) on suicide mortality. Daily temperature and suicide data for Helsinki were analyzed for the period of 1973-2010 inclusive. Overall, DTR reached its maximum during the spring from mid-April to mid-June, which is also the season with highest suicide mortality in the study region. Specifically, the seasonal timing and maxima for both DTR and suicides vary from year to year. Time series analysis of DTR and suicide records revealed a significant ( P < 0.01) correlation between the springtime DTR maxima and suicide rates for males. No similar association could be found for females. These results provide evidence that a higher springtime DTR could be linked statistically to a higher seasonal suicide rate each spring, whereas the exact timing of the DTR peak did not associate with the seasonal suicide rate. A possible mechanism behind the springtime association between the DTR and suicides originates from brown adipose tissue (BAT) over-activity. Activation of BAT through the winter improves cold tolerance at the cost of heat tolerance. This might trigger anxiety and psychomotor agitation, affecting mood in a negative way. As a hypothesis, the compromised heat tolerance is suggested to increase the risk of death from suicide.

  18. GISS Analysis of Surface Temperature Changes

    NASA Technical Reports Server (NTRS)

    Hansen, J.; Ruedy, R.; Glascoe, J.; Sato, M.

    1999-01-01

    We describe the current GISS analysis of surface temperature change based primarily on meteorological station measurements. The global surface temperature in 1998 was the warmest in the period of instrumental data. The rate of temperature change is higher in the past 25 years than at any previous time in the period of instrumental data. The warmth of 1998 is too large and pervasive to be fully accounted for by the recent El Nino, suggesting that global temperature may have moved to a higher level, analogous to the increase that occurred in the late 1970s. The warming in the United States over the past 50 years is smaller than in most of the world, and over that period there is a slight cooling trend in the Eastern United States and the neighboring Atlantic ocean. The spatial and temporal patterns of the temperature change suggest that more than one mechanism is involved in this regional cooling.

  19. Analysis of the diurnal development of the Ora del Garda wind in the Alps from airborne and surface measurements

    NASA Astrophysics Data System (ADS)

    Laiti, L.; Zardi, D.; de Franceschi, M.; Rampanelli, G.

    2013-07-01

    A lake-breeze and valley-wind coupled circulation system, known as Ora del Garda, typically arises in the late morning from the northern shorelines of Lake Garda (southeastern Italian Alps), and then channels into the Sarca and Lakes valleys to the north. After flowing over an elevated saddle, in the early afternoon this wind breaks out from the west into the nearby Adige Valley, hindering the regular development of the local up-valley wind by producing a strong and gusty anomalous flow in the area. Two targeted flights of an equipped motorglider were performed in the morning and afternoon of 23 August 2001 in the above valleys, exploring selected vertical slices of the atmosphere, from the lake's shore to the area where the two local airflows interact. At the same time, surface observations were collected during an intensive field measurement campaign held in the interaction area, as well as from routinely-operated weather stations disseminated along the whole study area, allowing the analysis of the different stages of the Ora del Garda development. From airborne measurements, an atmospheric boundary-layer (ABL) vertical structure, typical of deep Alpine valleys, was detected in connection with the wind flow, with rather shallow (∼500 m) convective mixed layers surmounted by deeper, weakly stable layers. On the other hand, close to the lake's shoreline the ABL was found to be stabilized down to very low heights, as an effect of the onshore advection of cold air by the lake breeze. Airborne potential temperature observations were mapped over high-resolution 3-D grids for each valley section explored by the flights, using a geostatistical technique called residual kriging (RK). RK-regridded fields revealed fine-scale features and inhomogeneities of ABL thermal structures associated with the complex thermally-driven wind field developing in the valleys. The combined analysis of surface observations and RK-interpolated fields revealed an irregular propagation of

  20. SEASONAL CHANGES IN TITAN'S SURFACE TEMPERATURES

    SciTech Connect

    Jennings, D. E.; Cottini, V.; Nixon, C. A.; Flasar, F. M.; Kunde, V. G.; Samuelson, R. E.; Romani, P. N.; Hesman, B. E.; Carlson, R. C.; Gorius, N. J. P.; Coustenis, A.; Tokano, T.

    2011-08-10

    Seasonal changes in Titan's surface brightness temperatures have been observed by Cassini in the thermal infrared. The Composite Infrared Spectrometer measured surface radiances at 19 {mu}m in two time periods: one in late northern winter (LNW; L{sub s} = 335 deg.) and another centered on northern spring equinox (NSE; L{sub s} = 0 deg.). In both periods we constructed pole-to-pole maps of zonally averaged brightness temperatures corrected for effects of the atmosphere. Between LNW and NSE a shift occurred in the temperature distribution, characterized by a warming of {approx}0.5 K in the north and a cooling by about the same amount in the south. At equinox the polar surface temperatures were both near 91 K and the equator was at 93.4 K. We measured a seasonal lag of {Delta}L{sub S} {approx} 9{sup 0} in the meridional surface temperature distribution, consistent with the post-equinox results of Voyager 1 as well as with predictions from general circulation modeling. A slightly elevated temperature is observed at 65{sup 0} S in the relatively cloud-free zone between the mid-latitude and southern cloud regions.

  1. Seasonal Changes in Titan's Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Jennins, Donald E.; Cottini, V.; Nixon, C. A.; Flasar, F. M.; Kunde, V. G.; Samuelson, R. E.; Romani, P. N.; Hesman, B. E.; Carlson, R. C.; Gorius, N. J. P.; Coustenis, A.; Tokano, T.

    2011-01-01

    Seasonal changes in Titan's surface brightness temperatures have been observed by Cassini in the thermal infrared. The Composite Infrared Spectrometer (CIRS) measured surface radiances at 19 micron in two time periods: one in late northern winter (Ls = 335d eg) and another centered on northern spring equinox (Ls = 0 deg). In both periods we constructed pole-to-pole maps of zonally averaged brightness temperatures corrected for effects of the atmosphere. Between late northern winter and northern spring equinox a shift occurred in the temperature distribution, characterized by a warming of approximately 0.5 K in the north and a cooling by about the same amount in the south. At equinox the polar surface temperatures were both near 91 K and the equator was 93.4 K. We measured a seasonal lag of delta Ls approximately 9 in the meridional surface temperature distribution, consistent with the post-equinox results of Voyager 1 as well as with predictions from general circulation modeling. A slightly elevated temperature is observed at 65 deg S in the relatively cloud-free zone between the mid-latitude and southern cloud regions.

  2. Calibration of surface temperature on rocky exoplanets

    NASA Astrophysics Data System (ADS)

    Kashyap Jagadeesh, Madhu

    2016-07-01

    Study of exoplanets and the search for life elsewhere has been a very fascinating area in recent years. Presently, lots of efforts have been channelled in this direction in the form of space exploration and the ultimate search for the habitable planet. One of the parametric methods to analyse the data available from the missions such as Kepler, CoRoT, etc, is the Earth Similarity Index (ESI), defined as a number between zero (no similarity) and one (identical to Earth), introduced to assess the Earth likeness of exoplanets. A multi-parameter ESI scale depends on the radius, density, escape velocity and surface temperature of exoplanets. Our objective is to establish how exactly the individual parameters, entering the interior ESI and surface ESI, are contributing to the global ESI, using the graphical analysis. Presently, the surface temperature estimates are following a correction factor of 30 K, based on the Earth's green-house effect. The main objective of this work in calculations of the global ESI using the HabCat data is to introduce a new method to better estimate the surface temperature of exoplanets, from theoretical formula with fixed albedo factor and emissivity (Earth values). From the graphical analysis of the known data for the Solar System objects, we established the calibration relation between surface and equilibrium temperatures for the Solar System objects. Using extrapolation we found that the power function is the closest description of the trend to attain surface temperature. From this we conclude that the correction term becomes very effective way to calculate the accurate value of the surface temperature, for further analysis with our graphical methodology.

  3. Effect of Diurnal Fluctuating versus Constant Temperatures on Germination of 445 Species from the Eastern Tibet Plateau

    PubMed Central

    Liu, Kun; Baskin, Jerry M.; Baskin, Carol C.; Bu, Haiyan; Du, Guozhen; Ma, Miaojun

    2013-01-01

    Germination response to fluctuating temperatures is a mechanism by which seeds detect gaps in vegetation canopies and depth of burial in soil, and it is very important for plants. Thus, studies on the effect of fluctuating temperature on germination at the community level are valuable for understanding community structure and biodiversity maintenance. We determined the effects of two alternating temperatures (5/25°C and 10/20°C) and one constant temperature (15°C) on seed germination of 445 species in a grassland community on the eastern Tibet Plateau. Seed mass was determined for each species, and data on habitat, type of life cycle, altitudinal distribution and functional group (graminoids or forbs) were obtained from the literature. Taking all species into account, alternating temperatures increased germination percentages regardless of amplitude. Overall, species growing in disturbed ground showed a significant germination response to temperature fluctuation, but those living in Alpine/subalpine meadow, forest margin /scrub, marshland and dry sunny slope habitats did not. Species distributed only at high elevations (>2000m) did not show a significant germination response to temperature fluctuation, whereas those occurring at both high and low elevations had a significant positive response. Germination of annuals/biennials was significantly promoted by 5/25°C, but not by 10/20°C, whereas germination of perennials was significantly promoted by both 5/25°C and 10/20°C. Small-seeded species were more likely than large-seeded species to respond positively to fluctuating temperatures. Germination of forbs had a positive response to temperature fluctuation, but germination of graminoids did not. Regeneration ability by seeds for about 36% of the species studied in the grassland can be increased by temperature fluctuation. The differential response among species to alternating vs. constant temperatures helps maintain community structure and biodiversity. A

  4. Validation of the MODIS Land-Surface Temperature Products with Temperature and Radiance-based Methods

    NASA Astrophysics Data System (ADS)

    Wan, Z.; Zhang, Y.; Zhang, Q.

    2003-12-01

    A major field campaign was conducted in Railroad Valley, NV, in June 2003. Ground-based measurements were made in the clear-sky days from June 26 to 30. Sky radiance and surface-leaving TIR radiance in sunshine and shadow conditions were measured with a Bomem TIR spectroradiometer. Diurnal surface temperatures were measured with four TIR radiometers. Six radio sounding balloons were launched in the period of clear-sky days to measure the atmospheric temperature and water vapor profiles. MODIS Airborne Simulator (MAS) data were acquired in a daytime flight and a nighttime flight on June 27. An excellent match between the measured spectral sky radiance and the radiance calculated with atmospheric radiative transfer code MODTRAN4.0 based on the measured atmospheric profiles provides a solid evidence of the good quality of both the TIR spectroradiometer and the radiative transfer code. The measured surface-leaving TIR radiance in sunshine and shadow conditions were used to retrieve playa surface spectral emissivity by a sun-shadow method. The band-averaged emissivities calculated from the retrieved spectral emissivity agree within 0.005 with those used in the MODIS split-window LST algorithm for the site. Terra and Aqua MODIS 1km LST products were validated with a temperature-based method using the LSTs measured by the TIR radiometers at nights. This method is limited by the spatial variation in LSTs, which is obviously shown in the day and night MAS images. The LST products were also validated in day and night conditions with a radiance-based method, which is based on the MODTRAN code, measured surface emissivity and atmospheric profiles. The LST accuracies are better than 1K in all seven Aqua cases where zenith viewing angles are up to 56\\deg, and in four of six Terra cases. The LST accuracy is better than 1.5K in the remaining two Terra cases with viewing angles at 54\\deg and 60\\deg. The accuracy of nighttime LSTs at viewing angles within 47\\deg is better than 0

  5. Did surface temperatures constrain microbial evolution?

    NASA Technical Reports Server (NTRS)

    Schwartzman, D.; McMenamin, M.; Volk, T.

    1993-01-01

    The proposition that glaciation may not have occurred before the Cenozoic--albeit not yet a consensus position--nevertheless raises for reconsideration the surface temperature history of the earth. Glacial episodes, from the Huronian (2.3 billion years ago; BYA) through the late Paleozoic (320 to 250 million years ago; MYA) have been critical constraints on estimation of the upper bounds of temperature (Crowley 1983, Kasting and Toon 1989). Once removed, few if any constraints on the upper temperature limit other than life remain. Walker (1982) recognized that life provides an upper limit to temperature in the Precambrian. We propose a more radical concept: the upper temperature limit for viable growth of a given microbial group corresponds to the actual surface temperature at the time of the group's first appearance. In particular, we propose here that two major evolutionary developments--the emergence of cyanobacteria and aerobic eukaryotes--can be used to determine surface temperature in the Precambrian, and that only subsequent cooling mediated by higher plants and then angiosperms permitted what may possibly be the earth's first glaciation in the late Cenozoic.

  6. Ameliorative effects of melatonin administration and photoperiods on diurnal fluctuations in cloacal temperature of Marshall broiler chickens during the hot dry season

    NASA Astrophysics Data System (ADS)

    Sinkalu, Victor O.; Ayo, Joseph O.; Adelaiye, Alexander B.; Hambolu, Joseph O.

    2015-01-01

    Experiments were performed with the aim of determining the effect of melatonin administration on diurnal fluctuations in cloacal temperature (CT) of Marshall broiler chickens during the hot dry season. Birds in group I (12L:12D cycle) were raised under natural photoperiod of 12-h light and 12-h darkness, without melatonin supplementation, while those in group II (LL) were kept under 24-h continuous lighting, without melatonin administration. Broiler chickens in group III (LL + melatonin) were raised under 24-h continuous lighting, with melatonin supplementation at 0.5 mg/kg per os. The cloacal temperatures of 15 labeled broiler chickens from each group were measured at 6:00, 13:00, and 19:00 h, 7 days apart, from days 14-42. Temperature-humidity index was highest at day 14 of the study, with the value of 36.72 ± 0.82 °C but lowest at day 28 with the value of 30.91 ± 0.80 °C ( P < 0.0001). The overall mean hourly cloacal temperature value of 41.51 ± 0.03 °C obtained in the 12L:12D cycle birds was significantly higher ( P < 0.001) than the value of 41.16 ± 0.03 °C recorded in the melatonin-treated group but lower than that of 41.65 ± 0.03 °C obtained in the LL birds. Mortality due to hyperthermia commenced at day 28 in both 12L:12D cycle and LL broiler chickens but was delayed till day 42 in LL + MEL broiler chickens. In conclusion, melatonin administration alleviated the deleterious effects of heat stress on broiler chickens by maintaining their cloacal temperature at relatively low values.

  7. Diurnal behavior of the carbon dioxide flux and change in the isotopic ratio δ13C in surface and near-bottom water in littoral of Lake Baikal

    NASA Astrophysics Data System (ADS)

    Panchenko, Mikhail V.; Domysheva, Valentina M.; Padalko, Natalia L.; Chernikov, Eugenii V.; Prazdnichnykh, Maxim I.; Tumakov, Alexander G.; Pestunov, Dmitrii A.

    2014-11-01

    Lake Baikal is one of the unique natural environments in Siberia which, to a large extent, affects the state of the nature in this region. The processes of gas exchange in the "water-atmosphere" system have been studied in Lake Baikal since 2002. The main purpose of the integrated investigations of exchange of carbon-containing gases in the water-atmosphere system in Lake Baikal is to study the contribution of physical, chemical, and biological components of the process and their interrelation with the intensity and rhythms of the fluxes. In 2013, the integrated measurements in the littoral area of Baikal were complemented with studies of the diurnal dynamics of isotopic ratio δ 13C in the surface and near-bottom water, which were not yet performed in Baikal before. In this work, we analyze first results of the joint analysis of RO2 fluxes in the "atmosphere - water surface" system and δ 13C, obtained in August 2013 in the littoral area of South Baikal. It is shown that d13C markedly increases in the surface waters at daylight time. In nighttime period, there takes place a reverse process, when δ 13C of the surface water approaches δ 13C, which is recorded for near-bottom water.

  8. Twentieth-Century Sea Surface Temperature Trends

    PubMed

    Cane; Clement; Kaplan; Kushnir; Pozdnyakov; Seager; Zebiak; Murtugudde

    1997-02-14

    An analysis of historical sea surface temperatures provides evidence for global warming since 1900, in line with land-based analyses of global temperature trends, and also shows that over the same period, the eastern equatorial Pacific cooled and the zonal sea surface temperature gradient strengthened. Recent theoretical studies have predicted such a pattern as a response of the coupled ocean-atmosphere system to an exogenous heating of the tropical atmosphere. This pattern, however, is not reproduced by the complex ocean-atmosphere circulation models currently used to simulate the climatic response to increased greenhouse gases. Its presence is likely to lessen the mean 20th-century global temperature change in model simulations. PMID:9020074

  9. Surface air temperature and its changes over the past 150 years

    NASA Astrophysics Data System (ADS)

    Jones, P. D.; New, M.; Parker, D. E.; Martin, S.; Rigor, I. G.

    1999-05-01

    We review the surface air temperature record of the past 150 years, considering the homogeneity of the basic data and the standard errors of estimation of the average hemispheric and global estimates. We present global fields of surface temperature change over the two 20-year periods of greatest warming this century, 1925-1944 and 1978-1997. Over these periods, global temperatures rose by 0.37° and 0.32°C, respectively. The twentieth-century warming has been accompanied by a decrease in those areas of the world affected by exceptionally cool temperatures and to a lesser extent by increases in areas affected by exceptionally warm temperatures. In recent decades there have been much greater increases in night minimum temperatures than in day maximum temperatures, so that over 1950-1993 the diurnal temperature range has decreased by 0.08°C per decade. We discuss the recent divergence of surface and satellite temperature measurements of the lower troposphere and consider the last 150 years in the context of the last millennium. We then provide a globally complete absolute surface air temperature climatology on a 1° × 1° grid. This is primarily based on data for 1961-1990. Extensive interpolation had to be undertaken over both polar regions and in a few other regions where basic data are scarce, but we believe the climatology is the most consistent and reliable of absolute surface air temperature conditions over the world. The climatology indicates that the annual average surface temperature of the world is 14.0°C (14.6°C in the Northern Hemisphere (NH) and 13.4°C for the Southern Hemisphere). The annual cycle of global mean temperatures follows that of the land-dominated NH, with a maximum in July of 15.9°C and a minimum in January of 12.2°C.

  10. Surface temperature effect on subsonic stall.

    NASA Technical Reports Server (NTRS)

    Macha, J. M.; Norton, D. J.; Young, J. C.

    1972-01-01

    Results of an analytical and experimental study of boundary layer flow over an aerodynamic surface rejecting heat to a cool environment. This occurs following reentry of a Space Shuttle vehicle. Analytical studies revealed that a surface to freestream temperature ratio, greater than unity tended to destabilize the boundary layer, hastening transition and separation. Therefore, heat transfer accentuated the effect of an adverse pressure gradient. Wind tunnel tests of a 0012-64 NACA airfoil showed that the stall angle was significantly reduced while drag tended to increase for freestream temperature ratios up to 2.2.

  11. Seasonal Surface Temperature Changes on Titan

    NASA Astrophysics Data System (ADS)

    Jennings, Donald E.; Cottini, Valeria; Nixon, Conor A.; Coustenis, Athena; Tokano, Tetsuya

    2015-11-01

    The Composite Infrared Spectrometer (CIRS) on Cassini has been measuring surface brightness temperatures on Titan since 2004 (Jennings et al. 2011; Cottini et al. 2012; Tan et al. 2015). Radiation from the surface reaches space through a window of minimum opacity in Titan’s atmosphere near 19 microns wavelength. We mapped surface temperatures in five time periods, each about 2 years, centered on solar longitudes Ls = 313°, 335°, 0°, 28° and 53° degrees. Using zonally-averaged spectra binned in 10-degree latitude intervals, we clearly see the seasonal progression of the pole-to-pole temperature distribution. Whereas peak temperatures in the vicinity of the Equator have been close to 94 K throughout the Cassini mission, early in the mission temperatures at the North Pole were as low as 90 K and at the South Pole were 92 K. Late in the mission the pattern has reversed: 92 K in the north and 90 K in the south. Over 2005 to 2014 the peak temperature moved in latitude from about 15 S to 15 N. We estimate a seasonal lag of 0.2 Titan month. In 2010 the temperature distribution was approximately symmetric north and south, agreeing with Voyager 1 from one Titan year earlier. The surface temperatures follow closely the predictions of Tokano (2005). Our measurements may indicate a lower thermal inertia in the south than in the north.Jennings, D.E. et al., ApJ Lett. 737, L15 (2011)Cottini, V. et al., 2012. Planet. Space Sci. 60, 62 (2012)Tan, S. P. et al., Icarus 250, 64 (2015)Tokano, T., Icarus 204, 619 (2005)

  12. Chemical Sputtering of Deuterated Carbon Surfaces at Various Surface Temperatures

    SciTech Connect

    Dadras, J.; Krstic, Predrag S

    2010-01-01

    The chemical sputtering of deuterated amorphous carbon (a-C:D) surfaces irradiated by 1 50 eV deuterium atoms at surface temperatures between 300 1000 K was studied using classical molecular dynamics. A quasi-stationary state was reached by cumulative bombardment for each energy and temperature. Results were compared with available experimental data and previous modeling results, and the applicability of molecular dynamics for thermally generated processes was discussed. An attempt is made to correct the absence of the thermally stimulated desorption/degassing form the MD simulations, which evolve at the longer time scales.

  13. Spacecraft ram glow and surface temperature

    NASA Technical Reports Server (NTRS)

    Swenson, G. R.; Mende, S. B.; Llewellyn, E. J.

    1987-01-01

    Space shuttle glow intensity measurements show large differences when the data from different missions are compared. In particular, on the 41-G mission the space shuttle ram glow was observed to display an unusually low intensity. Subsequent investigation of this measurement and earlier measurements suggest that there was a significant difference in temperature of the glow producing ram surfaces. The highly insulating properties coupled with the high emissivity of the shuttle tile results in surfaces that cool quickly when exposed to deep space on the night side of the orbit. The increased glow intensity is consistent with the hypothesis that the glow is emitted from excited NO2. The excited NO2 is likely formed through three body recombination (OI + NO + M = NO2*) where ramming of OI interacts with weakly surface bound NO. The NO is formed from atmospheric OI and NI which is scavenged by the spacecraft moving through the atmosphere. It is postulated that the colder surfaces retain a thicker layer of NO thereby increasing the probability of the reaction. It has been found from the glow intensity/temperature data that the bond energy of the surface bound precursor, leading to the chemical recombination producing the glow, is approximately 0.14 eV. A thermal analysis of material samples of STS-8 was made and the postulated temperature change of individual material samples prior to the time of glow measurements above respective samples are consistent with the thermal effect on glow found for the orbiter surface.

  14. Impact of diurnal temperature variation on grape berry development, proanthocyanidin accumulation, and the expression of flavonoid pathway genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about the impact of temperature on proanthocyanidin (PA) accumulation in grape skins, despite its significance in berry composition and wine quality. Field grown grapes (cv. Merlot) were cooled during the day or heated at night by +/- 8 °C, from fruit set to véraison in three seasons...

  15. Diurnal pollen tube growth is exceptionally sensitive to high temperature in field-grown Gossypium hirsutum pistils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For Gossypium hirsutum L. pollination, germination, and pollen tube growth must occur in a highly concerted fashion on the day of flowering for fertilization to occur. Because reproductive success is influenced by photosynthetic activity of major source leaves, we hypothesized that high temperatures...

  16. DIURNAL AND SEASONAL PATTERNS OF TEMPERATURE AND WIND FLOW IN THE PLANETARY BOUNDARY LAYER FOR TEN LOCATIONS IN COMPLEX TERRAIN

    EPA Science Inventory

    In support of the Complex Terrain Model Development program, climatological summaries in the form of vertical profiles of wind and temperature were produced from a special computer file of radiosonde data created from twice daily observations recorded at ten National Weather Serv...

  17. GISS Analysis of Surface Temperature Change

    NASA Technical Reports Server (NTRS)

    Hansen, J.; Ruedy, R.; Glascoe, J.; Sato, M.

    1999-01-01

    We describe the current GISS analysis of surface temperature change for the period 1880-1999 based primarily on meteorological station measurements. The global surface temperature in 1998 was the warmest in the period of instrumental data. The rate of temperature change was higher in the past 25 years than at any previous time in the period of instrumental data. The warmth of 1998 was too large and pervasive to be fully accounted for by the recent El Nino. Despite cooling in the first half of 1999, we suggest that the mean global temperature, averaged over 2-3 years, has moved to a higher level, analogous to the increase that occurred in the late 1970s. Warming in the United States over the past 50 years has been smaller than in most of the world, and over that period there was a slight cooling trend in the Eastern United States and the neighboring Atlantic Ocean. The spatial and temporal patterns of the temperature change suggest that more than one mechanism was involved in this regional cooling. The cooling trend in the United States, which began after the 1930s and is associated with ocean temperature change patterns, began to reverse after 1979. We suggest that further warming in the United States to a level rivaling the 1930s is likely in the next decade, but reliable prediction requires better understanding of decadal oscillations of ocean temperature.

  18. Trends in Surface Temperature from AIRS.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Aumann, H. H.

    2014-12-01

    To address possible causes of the current hiatus in the Earth's global temperature we investigate the trends and variability in the surface temperature using retrievals obtained from the measurements by the Atmospheric Infrared Sounder (AIRS) and its companion instrument, the Advanced Microwave Sounding Unit (AMSU), onboard of Aqua spacecraft in 2002-2014. The data used are L3 monthly means on a 1x1degree spatial grid. We separate the land and ocean temperatures, as well as temperatures in Artic, Antarctic and desert regions. We find a monotonic positive trend for the land temperature but not for the ocean temperature. The difference in the regional trends can help to explain why the global surface temperature remains almost unchanged but the frequency of occurrence of the extreme events increases under rising anthropogenic forcing. The results are compared with the model studies. This work was supported by the Jet Propulsion Laboratory of the California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  19. Spatial and Temporal Variations in Titan's Surface Temperatures from Cassini CIRS Observations

    NASA Technical Reports Server (NTRS)

    Cottini, V.; Nixon, C. A.; Jennings, D. E.; deKok, R.; Teanby, N. A.; Irwin, P. G. J.; Flasar, F. M.

    2012-01-01

    We report a wide-ranging study of Titan's surface temperatures by analysis of the Moon's outgoing radiance through a spectral window in the thermal infrared at 19 mm (530/cm) characterized by lower atmospheric opacity. We begin by modeling Cassini Composite Infrared Spectrometer (CIRS) far infrared spectra collected in the period 2004-2010, using a radiative transfer forward model combined with a non-linear optimal estimation inversion method. At low-latitudes, we agree with the HASI near-surface temperature of about 94 K at 101S (Fulchignoni et al., 2005). We find a systematic decrease from the equator toward the poles, hemispherically asymmetric, of approx. 1 K at 60 deg. south and approx. 3 K at 60 deg. north, in general agreement with a previous analysis of CIRS data and with Voyager results from the previous northern winter. Subdividing the available database, corresponding to about one Titan season, into 3 consecutive periods, small seasonal changes of up to 2 K at 60 deg N became noticeable in the results. In addition, clear evidence of diurnal variations of the surface temperatures near the equator are observed for the first time: we find a trend of slowly increasing temperature from the morning to the early afternoon and a faster decrease during the night. The diurnal change is approx. 1.5 K, in agreement with model predictions for a surface with a thermal inertia between 300 and 600 J/ sq. m s (exp -1/2) / K. These results provide important constraints on coupled surface-atmosphere models of Titan's meteorology and atmospheric dynamic.

  20. DISAGGREGATION OF GOES LAND SURFACE TEMPERATURES USING SURFACE EMISSIVITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. Trends in Surface Temperature at High Latitudes

    NASA Technical Reports Server (NTRS)

    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

  2. Spatial-temporal analysis of building surface temperatures in Hung Hom

    NASA Astrophysics Data System (ADS)

    Zeng, Ying; Shen, Yueqian

    2015-12-01

    This thesis presents a study on spatial-temporal analysis of building surface temperatures in Hung Hom. Observations were collected from Aug 2013 to Oct 2013 at a 30-min interval, using iButton sensors (N=20) covering twelve locations in Hung Hom. And thermal images were captured in PolyU from 05 Aug 2013 to 06 Aug 2013. A linear regression model of iButton and thermal records is established to calibrate temperature data. A 3D modeling system is developed based on Visual Studio 2010 development platform, using ArcEngine10.0 component, Microsoft Access 2010 database and C# programming language. The system realizes processing data, spatial analysis, compound query and 3D face temperature rendering and so on. After statistical analyses, building face azimuths are found to have a statistically significant relationship with sun azimuths at peak time. And seasonal building temperature changing also corresponds to the sun angle and sun azimuth variations. Building materials are found to have a significant effect on building surface temperatures. Buildings with lower albedo materials tend to have higher temperatures and larger thermal conductivity material have significant diurnal variations. For the geographical locations, the peripheral faces of campus have higher temperatures than the inner faces during day time and buildings located at the southeast are cooler than the western. Furthermore, human activity is found to have a strong relationship with building surface temperatures through weekday and weekend comparison.

  3. Modelling of the Thermodynamical Diurnal Cycle in the Lower Atmosphere: A Joint Evaluation of Four Contrasted Regimes in the Tropics Over Land

    NASA Astrophysics Data System (ADS)

    Couvreux, F.; Guichard, F.; Gounou, A.; Bouniol, D.; Peyrillé, P.; Köhler, M.

    2013-10-01

    The diurnal cycle is an important mode of variability in the Tropics that is not correctly predicted by numerical weather prediction models. The African Monsoon Multidisciplinary Analyses program provided for the first time a large dataset to document the diurnal cycle over West Africa. In order to assess the processes and mechanisms that are crucial for the representation of the diurnal cycle, four different regimes that characterize the varying conditions encountered over land along a surface-temperature gradient are selected. A single-column modelling framework is used in order to relate the features of the simulated diurnal cycle to physical processes in these four distinct cases. Particular attention is given to providing realistic initial and boundary conditions at the surface and in the atmosphere, enabling the use of independent data for the evaluation of the simulations. The study focuses on the simulation of the surface energy budget and low-level characteristics and analyzes the balance between cloud/surface/boundary-layer processes at the sub-diurnal time scale. The biases and drawbacks of the simulations are found to change along the temperature gradient but they always involve the representation of clouds. They also explain parts of the bias obtained with the same model when used in a less constrained configuration. Surface-atmosphere-cloud interactions arising at the sub-diurnal time scale are invoked to explain the distinct features of the low-level diurnal cycle observed over West Africa.

  4. Seasonal Changes in Titan's Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Jennings, Donald E.; Nixon, Conor A.; Cottini, Valeria

    2011-01-01

    Cassini's extended mission has provided the opportunity to search for seasonal variations on Titan. In particular, surface temperatures are expected to have shifted significantly in latitude during the completed portion of the mission. Spectra recorded by the Composite Infrared Spectrometer (CIRS) during the nominal mission (2004-08) and the Equinox mission. (2008-10) have already shown changes in temperature. CIRS has detected a seasonal shift in the latitudinal distribution of surface brightness temperatures by comparing zonal averages from two time segments, one period in late northern winter centered on L(sub s) approximately 335 deg and a second period centered on the equinox (L(sub s) approximately 0 deg.). The earlier period had a meridional distribution similar to that previously reported: 93.5 K at the equator, 91.7 K at 85 S and 899 K at 85 N. The newly measured distribution near equinox shows a cooling in the south and a warming in the north, both by about 0.5 K. We estimate that. the centroid of the distribution moved from approximately 16 S to 7 S between the two periods. This gives a seasonal lag behind insolation of delta L(sub s) approximately 13 deg. The CIRS equinox results are consistent with those of Voyager IRIS, which encountered Titan in November 1980, just following the previous northern equinox (L(sub s) = 10 deg.). When compared with predictions from general circulation models, seasonal variations of surface temperature can help constrain the identification of surface materials. Our measurements most closely match the case of a porous ice regolith treated by Tokano, but with some apparent differences between the northern and southern hemispheres. CIRS will extend its study of seasonal variations in surface temperature on Titan as Cassini continues through northern spring.

  5. Diurnal cycle of O[sub 3] and monoterpenes in a coniferous forest: Importance of atmospheric stability, surface exchange, and chemistry

    SciTech Connect

    Johansson, C.; Janson, R.W. )

    1993-03-20

    A one-dimensional model of turbulent diffusion and chemistry has been applied to evaluate measurements of the diurnal variation of O[sub 3] and monoterpenes in a coniferous forest in Sweden. The role of photochemical, meteorological, and surface exchange processes was investigated by studying days characteristic of neutral and stable/unstable conditions, respectively. The atmospheric concentrations and surface exchange rates of O[sub 3], monoterpenes and NO[sub x] were taken from measurements at the site, using chamber techniques for the flux measurements. The model calculations showed the predominant role of turbulent mixing in the observed diurnal variation of O[sub 3] and monoterpenes. The reaction with OH accounted for 50-60% of the terpene loss over a 24-hour period with a well-mixed boundary layer and about 40% when nighttime conditions were stable. Increasing the background O[sub 3] concentration to 80-90 ppbv increased the relative importance of the terpene + O[sub 3] reaction to equal that of the OH reaction. The terpene chemical lifetime was found to be shortest, less than 1 hour, under neutral nighttime conditions when NO[sub 3] concentrations were high. Under stable nighttime conditions, the lower boundary layer became chemically less active due to the depletion of O[sub 3] and NO[sub 3]. Terpene reactions were found to be significant nighttime sinks for O[sub 3] and NO[sub 3] under stable conditions and during periods or at sites of nocturnal terpene emission rates greater than 150 [mu]g/m[sup 2] h. An increase in NO[sub x] concentrations from 0.5 ppbv to 1 and then 5 ppbv, changed O[sub 3] concentrations first up and then down, by not more than 1 ppbv. At terpene emission rates of 50-100 [mu]g (m[sup 2] h)[sup [minus]1], the terpene + OH reaction caused less than 5% of the OH loss near the surface, while at a rate of 1,500 [mu]g (m[sup 2] h)[sup [minus]1], it accounted for up to 30-40% of OH loss. 54 refs., 8 figs., 2 tabs.

  6. Global patterns in lake surface temperature trends

    NASA Astrophysics Data System (ADS)

    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.

  7. Impact of diurnal temperature variation on grape berry development, proanthocyanidin accumulation, and the expression of flavonoid pathway genes

    PubMed Central

    Cohen, Seth D.; Tarara, Julie M.; Gambetta, Greg A.; Matthews, Mark A.; Kennedy, James A.

    2012-01-01

    Little is known about the impact of temperature on proanthocyanidin (PA) accumulation in grape skins, despite its significance in berry composition and wine quality. Field-grown grapes (cv. Merlot) were cooled during the day or heated at night by +/–8 °C, from fruit set to véraison in three seasons, to determine the effect of temperature on PA accumulation. Total PA content per berry varied only in one year, when PA content was highest in heated berries (1.46 mg berry−1) and lowest in cooled berries (0.97 mg berry−1). In two years, cooling berries resulted in a significant increase in the proportion of (–)-epigallocatechin as an extension subunit. In the third year, rates of berry development, PA accumulation, and the expression levels of several genes involved in flavonoid biosynthesis were assessed. Heating and cooling berries altered the initial rates of PA accumulation, which was correlated strongly with the expression of core genes in the flavonoid pathway. Both heating and cooling altered the rate of berry growth and coloration, and the expression of several structural genes within the flavonoid pathway. PMID:22268158

  8. Global modeling of fresh surface water temperature

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Temperature determines a range of water physical properties, the solubility of oxygen and other gases and acts as a strong control on fresh water biogeochemistry, influencing chemical reaction rates, phytoplankton and zooplankton composition and the presence or absence of pathogens. Thus, in freshwater ecosystems the thermal regime affects the geographical distribution of aquatic species through their growth and metabolism, tolerance to parasites, diseases and pollution and life history. Compared to statistical approaches, physically-based models of surface water temperature have the advantage that they are robust in light of changes in flow regime, river morphology, radiation balance and upstream hydrology. Such models are therefore better suited for projecting the effects of global change on water temperature. Till now, physically-based models have only been applied to well-defined fresh water bodies of limited size (e.g., lakes or stream segments), where the numerous parameters can be measured or otherwise established, whereas attempts to model water temperature over larger scales has thus far been limited to regression type of models. Here, we present a first attempt to apply a physically-based model of global fresh surface water temperature. The model adds a surface water energy balance to river discharge modelled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by short and long-wave radiation and sensible and latent heat fluxes. Also included are ice-formation and its effect on heat storage and river hydraulics. We used the coupled surface water and energy balance model to simulate global fresh surface water temperature at daily time steps on a 0.5x0.5 degree grid for the period 1970-2000. Meteorological forcing was obtained from the CRU data set, downscaled to daily values with ECMWF

  9. Observations of SST diurnal variability in the South China Sea

    NASA Astrophysics Data System (ADS)

    Tu, Qianguang; Pan, Delu; Hao, Zengzhou; Chen, Jianyu

    2015-10-01

    In this study, a 3-hourly time resolution gap free sea surface temperature (SST) analysis is generated to resolve the diurnal cycle in the South China Sea (SCS, 0°-25°N, 100°-125°E).It takes advantage of hourly geostationary satellite MTSAT observations and combines three infrared and two microwave polar satellite observations at different local times. First, all the data are classified into eight SST datasets at 3 hour intervals and then remapped to 0.05°resolution grids. A series of critical quality control is done to remove the outliers.Then bias adjustment is applied to the polar satellite observations with reference to the MTSAT data. Finally, the six satellites SST data are blended by using the optimal interpolated algorithm. The 3-hourly blended SST is compared against buoy measurements. It shows a good agreement that the biases do not exceed 0.2 °C and root mean square errors range from 0.5 to 0.65 °C. A typical diurnal cycle similar to sine wave is observed. The minimum SST occurs at around 0600h and warming peak occurring between 1300h and 1500h local solar time and then decrease in the late afternoon, tapering off at night on March 13, 2008 for example. The frequency of diurnal warming events derived from four years of the blended SST provides solid statistics to investigate the seasonal and spatial distributions of the diurnal warming in the SCS. The sea surface diurnal warming tends to appear more easily in spring, especially in the coastal regions than other seasons and the central regions.

  10. Global Surface Temperatures of the Moon

    NASA Astrophysics Data System (ADS)

    Williams, J. P.; Paige, D. A.; Greenhagen, B. T.; Sefton-Nash, E.

    2015-12-01

    The Diviner instrument aboard the Lunar Reconnaissance Orbiter (LRO) is providing the most comprehensive view of how regoliths on airless body store and exchange thermal energy with the space environment. Approximately a quarter trillion calibrated radiance measurements of the Moon, acquired over 5.5 years by Diviner, have been compiled into a 0.5° resolution global dataset with a 0.25 hour local time resolution. Maps generated with this dataset provide a global perspective of the surface energy balance of the Moon and reveal the complex and extreme nature of the lunar surface thermal environment. Daytime maximum temperatures are sensitive to the radiative properties of the surface and are ~387-397 K at the equator, dropping to ~95 K before sunrise. Asymmetry between the morning and afternoon temperatures is observed due to the thermal inertia of the regolith with the dusk terminator ~30 K warmer than the dawn terminator at the equator. An increase in albedo with incidence angle is required to explain the observed temperatures with latitude. At incidence angles >40° topography and surface roughness result in increasing anisothermality between spectral passbands and scatter in temperatures. Minimum temperatures reflect variations in thermophysical properties (Figure). Impact craters are found to modify regolith properties over large distances. The thermal signature of Tycho is asymmetric consistent with an oblique impact coming from the west. Some prominent crater rays are visible in the thermal data and require material with a higher thermal inertial than nominal regolith. The influence of the formation of the Orientale basin on the regolith properties is observable over a substantial portion of the western hemisphere despite its age (~3.8 Gyr), and may have contributed to mixing of highland and mare material on the southwest margin of Oceanus Procellarum where the gradient in radiative properties at the mare-highland contact are observed to be broad (~200 km).

  11. Gender, Age and Season as Modifiers of the Effects of Diurnal Temperature Range on Emergency Room Admissions for Cause-Specific Cardiovascular Disease among the Elderly in Beijing

    PubMed Central

    Zheng, Shan; Wang, Minzhen; Li, Bei; Wang, Shigong; He, Shilin; Yin, Ling; Shang, Kezheng; Li, Tanshi

    2016-01-01

    Background: Diurnal temperature range (DTR) is an important index of climate change and variability. It is also a risk factor affecting human health. However, limited evidence is available to illustrate the effect of DTR modification on cause-specific cardiovascular disease among the elderly. Methods: A semi-parametric generalized additive model (GAM) was used to analyze the exposure-effect relationship between DTR and daily emergency room (ER) admissions for cause-specific cardiovascular diseases among the elderly from 2009 to 2011 in Beijing. We examined the effects of DTR for stratified groups by gender and age, and examined the effects of DTR in the warm season and cold season for cause-specific cardiovascular diseases. Results: Significant associations were found between DTR and ER admissions for all cardiovascular and cerebrovascular disease among elderly males, while DTR was significantly associated with ER admissions for all cardiovascular disease, ischemic heart disease and cerebrovascular disease among elderly females. People aged 75 years and older were more vulnerable to DTR. DTR caused greater adverse effects on both genders in the warm season, whereas the effect estimates on females were higher in cold season than in warm season. Conclusions: A short-term increase of DTR was significantly associated with ER admissions for cause-specific cardiovascular disease among the elderly in Beijing. Gender, age and season may modify the acute health effect of DTR. Some prevention programs that target the high risk subgroups in the elderly for impending large temperature changes may reduce the impact of DTR on people’s health. PMID:27128931

  12. Diurnal and Seasonal Change in Stem Respiration of Larix principis-rupprechtii Trees, Northern China

    PubMed Central

    Yang, Yan; Zhao, Miao; Xu, Xiangtao; Sun, Zhenzhong; Yin, Guodong; Piao, Shilong

    2014-01-01

    Stem respiration is a critical and uncertain component of ecosystem carbon cycle. Few studies reported diurnal change in stem respiration as well as its linkage with climate. In this study, we investigated the diurnal and seasonal change in stem respiration and its linkage with environmental factors, in larch plantations of northern China from 2010 to 2012. The stem respiration per unit surface area (RS) showed clear diurnal cycles, ranging from 1.65±0.10 to 2.69±0.15 µmol m−2 s−1, increased after 6∶00, peaked at 15∶00 and then decreased. Both stem temperature and air temperature show similar diurnal pattern, while the diurnal pattern of air relative humidity is just the opposite to Rs. Similar to the diurnal cycles, seasonal change in RS followed the pattern of stem temperature. RS increased from May (1.28±0.07 µmol m−2 s−1) when the stem temperature was relatively low and peaked in July (3.02±0.10 µmol m−2 s−1) when the stem temperature was also the highest. Further regression analyses show that RS exponentially increases with increasing temperature, and the Q10 of Rs at mid daytime (1.97±0.17 at 12∶00 and 1.96±0.10 at 15∶00) is significantly lower than that of mid nighttime (2.60±0.14 at 00∶00 and 2.71±0.25 at 03∶00) Q10. This result not only implies that Rs is more sensitive to night than day warming, but also highlights that temperature responses of Rs estimated by only daytime measurement can lead to underestimated stem respiration increase under global warming, especially considering that temperature increase is faster during nighttime. PMID:24586668

  13. Upscaling and Downscaling of Land Surface Fluxes with Surface Temperature

    NASA Astrophysics Data System (ADS)

    Kustas, W. P.; Anderson, M. C.; Hain, C.; Albertson, J. D.; Gao, F.; Yang, Y.

    2015-12-01

    Land surface temperature (LST) is a key surface boundary condition that is significantly correlated to surface flux partitioning between latent and sensible heat. The spatial and temporal variation in LST is driven by radiation, wind, vegetation cover and roughness as well as soil moisture status in the surface and root zone. Data from airborne and satellite-based platforms provide LST from ~10 km to sub meter resolutions. A land surface scheme called the Two-Source Energy Balance (TSEB) model has been incorporated into a multi-scale regional modeling system ALEXI (Atmosphere Land Exchange Inverse) and a disaggregation scheme (DisALEXI) using higher resolution LST. Results with this modeling system indicates that it can be applied over heterogeneous land surfaces and estimate reliable surface fluxes with minimal in situ information. Consequently, this modeling system allows for scaling energy fluxes from subfield to regional scales in regions with little ground data. In addition, the TSEB scheme has been incorporated into a large Eddy Simulation (LES) model for investigating dynamic interactions between variations in the land surface state reflected in the spatial pattern in LST and the lower atmospheric air properties affecting energy exchange. An overview of research results on scaling of fluxes and interactions with the lower atmosphere from the subfield level to regional scales using the TSEB, ALEX/DisALEX and the LES-TSEB approaches will be presented. Some unresolved issues in the use of LST at different spatial resolutions for estimating surface energy balance and upscaling fluxes, particularly evapotranspiration, will be discussed.

  14. High temperature low friction surface coating

    DOEpatents

    Bhushan, Bharat

    1980-01-01

    A high temperature, low friction, flexible coating for metal surfaces which are subject to rubbing contact includes a mixture of three parts graphite and one part cadmium oxide, ball milled in water for four hours, then mixed with thirty percent by weight of sodium silicate in water solution and a few drops of wetting agent. The mixture is sprayed 12-15 microns thick onto an electro-etched metal surface and air dried for thirty minutes, then baked for two hours at 65.degree. C. to remove the water and wetting agent, and baked for an additional eight hours at about 150.degree. C. to produce the optimum bond with the metal surface. The coating is afterwards burnished to a thickness of about 7-10 microns.

  15. Satellite multi-sensor data analysis of urban surface temperatures and landcover

    NASA Astrophysics Data System (ADS)

    Dousset, B.; Gourmelon, F.

    Multiple satellite sensors are used to analyze physical processes that determine energy fluxes and their interaction at the urban surface. The study is based on summertime microclimate analyses of the Los Angeles and Paris metropolises. The method consists of deriving some parameters governing the surface heat fluxes, constructing statistics of thermal infrared images, and using a GIS to combine them with a landcover classification from SPOT-HRV multispectral images, and with data from intensive in-situ experiments. The average images reveal spatial and temporal variations of land surface temperature (LST), and distinct microclimatic patterns. The combined interpretation of the statistics images and of the landcover classification shows: (i) the effect of surface physical properties, especially in downtown business and industrial districts that display heat-islands larger than 7 °C; (ii) the temperating influence of water; (iii) the negative correlation between afternoon land surface temperature and normalized vegetation index, which confirms the cooling effect of urban parks; (iv) the correlation between variations of surface temperature and ozone concentration at diurnal and longer time scales.

  16. A method to estimate land surface temperature from Meteosat Second Generation data using multi-temporal data.

    PubMed

    Zhang, Xiaoyu; Li, Lingling

    2013-12-30

    Land surface temperature (LST) is key parameters in the interaction of land-atmosphere system. This paper proposed a method to inverse LST from multi-temporal thermal infrared remote sensing data based on the theory of split-window algorithm and diurnal temperature cycle model. The new method was validated by a diurnal brightness temperatures data sets corresponding to MSG2-SEVIRI, which was simulated by the atmospheric radiative transfer model MODTRAN 4 with several input parameters under clear sky, including near surface air temperature, atmospheric water, surface temperature and emissivity, and viewing angles, and result showed the root mean square error (RMSE) of LST reaches 1.2K for simulated data and most errors are within ± 2K with accurate parameters input. At the same time, comparison of LST estimated using the proposed method from MSG2-SEVIRI data with that from MOD11B1 V5 product displayed that the RMSE equals to 3.0K and most errors are distributed within ± 6K. But, the method is proposed under no cloudy condition and is tested only in mid-latitude and daytime; more validation should be made in different areas and atmospheric conditions. PMID:24514786

  17. Stratospheric Impact of Varying Sea Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Nielsen, Jon E.; Waugh, Darryn; Pawson, Steven

    2004-01-01

    The Finite-Volume General Circulation Model (FVGCM) has been run in 50 year simulations with the: 1) 1949-1999 Hadley Centre sea surface temperatures (SST), and 2) a fixed annual cycle of SSTs. In this presentation we first show that the 1949-1999 FVGCM simulation produces a very credible stratosphere in comparison to an NCEP/NCAR reanalysis climatology. In particular, the northern hemisphere has numerous major and minor stratospheric warming, while the southern hemisphere has only a few over the 50-year simulation. During the northern hemisphere winter, temperatures are both warmer in the lower stratosphere and the polar vortex is weaker than is found in the mid-winter southern hemisphere. Mean temperature differences in the lower stratosphere are shown to be small (less than 2 K), and planetary wave forcing is found to be very consistent with the climatology. We then will show the differences between our varying SST simulation and the fixed SST simulation in both the dynamics and in two parameterized trace gases (ozone and methane). In general, differences are found to be small, with subtle changes in planetary wave forcing that lead to reduced temperatures in the SH and increased temperatures in the NH.

  18. Assessment of model land skin temperature and surface-atmosphere coupling using remotely sensed estimates

    NASA Astrophysics Data System (ADS)

    Trigo, Isabel; Boussetta, Souhail; Balsamo, Gianpaolo; Viterbo, Pedro; Beljaars, Anton; Sandu, Irina

    2016-04-01

    The coupling between land surface and the atmosphere is a key feature in Earth System Modelling for exploiting the predictability of slowly evolving geophysical variables (e.g., soil moisture or vegetation state), and for correctly representing rapid variations within the diurnal cycle, particularly relevant in data assimilation applications. Land Surface Temperature (LST) routinely estimated from Meteosat Second Generation (MSG) by the LandSAF is used to assess the European Centre for Medium-range Weather Forecasts (ECMWF) skin temperature. LST can be interpreted as a radiative temperature of the model surface, which is close to the ECMWF modelled skin temperature. It is shown that the model tends to slightly overestimate skin temperature during night-time and underestimate daytime values. Such underestimation of daily amplitudes is particularly pronounced in (semi-)arid regions, suggesting a misrepresentation of surface energy fluxes in those areas. The LST estimated from MSG is used to evaluate the impact of changes in some of the ECMWF model surface parameters. The introduction of more realistic model vegetation is shown to have a positive, but limited impact on skin temperature: long integration leads to an equilibrium state where changes in the latent heat flux and soil moisture availability compensate each other. Revised surface roughness lengths for heat and momentum, however, lead to overall positive impact on daytime skin temperature, mostly due to a reduction of sensible heat flux. This is particularly relevant in non-vegetated areas, unaffected by model vegetation. The reduction of skin conductivity, a parameter which controls the heat transfer to ground by diffusion, is shown to further improve the model skin temperature. A revision of the vertical soil discretization is also expected to improve the match to the LST, particularly over sparsely vegetated areas. The impact of a finer discretization (10-layer soil) is currently ongoing; preliminary

  19. Investigating Crevasse Structure Impact on Glacial Sub-Surface Ice Temperature Distribution with Implications for Moulin Formation

    NASA Astrophysics Data System (ADS)

    Hurley, A.; Lampkin, D.

    2008-12-01

    Ice flow acceleration in the ablation zone of outlet glaciers in Greenland has been linked to an increase in infiltration of surface melt through moulins. In order to understand the potential for moulin formation within cracks and crevasses in glacial ice and their impact on melt infiltration rates it is important to gain knowledge about how crevasse structure influences sub-surface ice cold content. A tower of seven wireless sensors was deployed in a moulin at the base of a crevasse in Svinasfellsjokull, glacier in Iceland as an analog to those in Greenland to measure temperature and incoming solar radiation at depth. Seven Crossbow® Environmental Motes (MEP410 Models) measuring temperature and irradiance (integrated from 0.4- 0.6μm) were deployed and inserted in a moulin at a depth of 156.8 cm for three days. Temperature measurements indicate greater diurnal fluctuations near the surface of 0.39 °C from the near surface mote, while sub-surface temperature remain stable near mean temperature of -0.05 °C at a depth of 139.8 cm. Incoming solar radiation measurements showed diurnal variation as expected near the surface at 5.30 W/m2 in the top of the sensor tower, whereas no variation occurred at other depths as the average was 0 W/m2. A computational fluid dynamic model has been calibrated by measured mote temperatures. The model was run accounting for diffusion and convective processes and forced with meteorological data to explore how crevasse density, depth, and geometry influence sub-surface ice temperature distribution.

  20. The Diurnal Cycle in TOGA-COARE: Regional Scale Model Simulations

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.; Jia, Y.

    1999-01-01

    The diurnal variation of precipitation processes over the tropics is a well-known phenomenon and has been studied using surface rainfall data, radar reflectivity data, and satellite-derived cloudiness and precipitation. Recently, analyzed observations from Tropical Oceans and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) in the tropical western Pacific ocean to study the relevant mechanisms producing diurnal variation of precipitation. They found that the diurnal Sea surface temperature (SST) cycle is important for afternoon showers in the undisturbed periods and diurnal radiative processes for nocturnal rainfall. Cloud resolving models (CRMS) have been used to determine the mechanisms associated with diurnal variation of precipitating processes. CRMs allow explicit cloud-radiation and air-sea interactive processes. However, CRMs can be only used for idealized simulations (i.e., no feedback between clouds and their embedded large-scale environments; cyclic lateral boundary conditions and idealized initial conditions). In this study, the Penn State/NCAR Mesoscale Model (MM5) with improved physics (i.e., cloud microphysics, radiation, land-soil-vegetation-surface processes, and TOGA COARE flux scheme) and a multiple level nesting technique (covers the TOGA COARE LSA/IFA with a 54 km grid and can nest down to 18, 6 and possibly even 2 km) will be adopted for studying the diurnal variations of rainfall. We will examine precipitation processes over open ocean and over land. We will also perform sensitivity tests to determine how the radiative forcing and diurnal SST cycle affects the development of convection.

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

    NASA Astrophysics Data System (ADS)

    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

  2. Antarctic surface temperature and pressure data

    SciTech Connect

    Jones, P.D.; Limbert, D.W.S.; Boden, T.A. . Climatic Research Unit; British Antarctic Survey, Cambridge; Oak Ridge National Lab., TN )

    1989-09-01

    This document presents monthly mean surface temperature and pressure data from 30 Antarctic stations. These data were assembled primarily from World Weather Records volumes for 1951--1960 and 1961--1979 and from Monthly Climatic Data for the World records since 1961. The periods of record vary by station. The earliest data are from 1903, and the most recent data are from 1988. All the assembled data were assessed for quality and for long-term homogeneity through the use of interstation comparison techniques. These data are available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center. The NDP consists of this document and a magnetic tape containing machine-readable data files. This document provides tabular listings of the temperature and pressure data, describes how the data were processed, defines limitations and restrictions of the data, and provides reprints of pertinent literature. 25 refs., 3 figs., 11 tabs.

  3. Sea surface temperature - Observations from geostationary satellites

    NASA Technical Reports Server (NTRS)

    Bates, J. J.; Smith, W. L.

    1985-01-01

    Multispectral image data acquired from the VISSR atmospheric sounder (VAS) on the geostationary GOES satellites were used to estimate sea surface temperatures (SST). A procedure was developed to screen VAS visible and infrared data for cloud-free regions for estimation of SST from the clear infrared radiances. A data set of matches between the VAS radiances and high quality buoy estimates of SST was produced. A linear regression analysis of these matches was performed to generate an empirical algorithm relating the VAS window channel brightness temperatures to the estimates of SST recorded by NOAA fixed environment buoys. Daily maps of SST during Hurricanes Alicia (1983) and Debbie (1982) demonstrated the ability of VAS to monitor air-sea interactions at high temporal and spatial scales.

  4. Sea surface temperature variability: patterns and mechanisms.

    PubMed

    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

  5. Sea Surface Temperature and Vegetation Index

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is a composite MODIS image showing the 'green wave' of spring in North America and sea surface temperature in the ocean, collected over an 8-day period during the first week in April 2000. On land, the darker green pixels show where the most green foliage is being produced due to photosynthetic activity. Yellows on land show where there is little or no productivity and red is a boundary zone. In the ocean, orange and yellows show warmer waters and blues show colder values.

  6. High temperature surface protection. [10 gas turbines

    NASA Technical Reports Server (NTRS)

    Levine, S. R.

    1978-01-01

    Alloys of the MCrAlX type are the basis for high temperature surface protection systems in gas turbines. M can be one or more of Ni, Co, or Fe and X denotes a reactive metal added to enhance oxide scale adherence. The selection and formation as well as the oxidation, hot corrosion and thermal fatigue performance of MCrAlX coatings are discussed. Coatings covered range from simple aluminides formed by pack cementation to the more advanced physical vapor deposition overlay coatings and developmental plasma spray deposited thermal barrier coatings.

  7. A global monthly sea surface temperature climatology

    SciTech Connect

    Shea, D.J.; Trenberth, K.E.; Reynolds, R.W. NOAA, Climate Analysis Center, Washington, DC )

    1992-09-01

    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. 22 refs.

  8. Eye surface temperature detects stress response in budgerigars (Melopsittacus undulatus).

    PubMed

    Ikkatai, Yuko; Watanabe, Shigeru

    2015-08-01

    Previous studies have suggested that stressors not only increase body core temperature but also body surface temperature in many animals. However, it remains unclear whether surface temperature could be used as an alternative to directly measure body core temperature, particularly in birds. We investigated whether surface temperature is perceived as a stress response in budgerigars. Budgerigars have been used as popular animal models to investigate various neural mechanisms such as visual perception, vocal learning, and imitation. Developing a new technique to understand the basic physiological mechanism would help neuroscience researchers. First, we found that cloacal temperature correlated with eye surface temperature. Second, eye surface temperature increased after handling stress. Our findings suggest that eye surface temperature is closely related to cloacal temperature and that the stress response can be measured by eye surface temperature in budgerigars. PMID:26103119

  9. Modern average global sea-surface temperature

    USGS Publications Warehouse

    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.

  10. The Met Office's new operational analysis system for diurnally varying skin-SST

    NASA Astrophysics Data System (ADS)

    While, James; Mao, Chongyuan; Martin, Matthew; Good, Simon; Sykes, Peter

    2016-04-01

    Diurnal variations in skin Sea Surface Temperature (skin SST), which can be as large as several degrees, play an important role in determining the heat flux between the ocean and atmosphere. As such, since February 2015 the Met Office, as part of the Copernicus Marine Environment Monitoring Service (CMEMS), has been producing an operational analysis of the diurnal cycle of skin SST. This product consists of three components: an underlying 'foundation' SST (based on the OSTIA analysis), a warm layer where solar heating is important, and a cool skin where cooling due to long wave radiation dominates. A major development in this system is the use of a 4D-Var data assimilation technique with multiple outer-loops to improve estimates of the warm layer. Observations assimilated come from the SEVIRI, GOES-W, MTSAT2, and NOAA-AVHRR infra-red satellite instruments. Through their assimilation, the observations act to update the applied heat and wind flux such that the diurnal cycle in the warm layer is improved. In this presentation we describe the analysis system and how it produces a skin SST product. Particular attention is paid to the data assimilation aspects and on the observation processing. We also present results from a three month validation period showing that the system is well able to reproduce a drifter based climatology of the diurnal cycle in SST. A direct validation of our diurnal SST output against near surface Argo data is also given.

  11. Surface Temperature Humidity Reference System Handbook - November 2005

    SciTech Connect

    MT Ritsche

    2005-11-30

    The Surface Temperature and Humidity Reference (SURTHREF) system is intended to provide accurate reference values of ambient temperature and relative humidity for comparison with radiosonde prelaunch values.

  12. Improving the Accuracy of Satellite Sea Surface Temperature Measurements by Explicitly Accounting for the Bulk-Skin Temperature Difference

    NASA Technical Reports Server (NTRS)

    Wick, Gary A.; Emery, William J.; Castro, Sandra L.; Lindstrom, Eric (Technical Monitor)

    2002-01-01

    The focus of this research was to determine whether the accuracy of satellite measurements of sea surface temperature (SST) could be improved by explicitly accounting for the complex temperature gradients at the surface of the ocean associated with the cool skin and diurnal warm layers. To achieve this goal, work was performed in two different major areas. The first centered on the development and deployment of low-cost infrared radiometers to enable the direct validation of satellite measurements of skin temperature. The second involved a modeling and data analysis effort whereby modeled near-surface temperature profiles were integrated into the retrieval of bulk SST estimates from existing satellite data. Under the first work area, two different seagoing infrared radiometers were designed and fabricated and the first of these was deployed on research ships during two major experiments. Analyses of these data contributed significantly to the Ph.D. thesis of one graduate student and these results are currently being converted into a journal publication. The results of the second portion of work demonstrated that, with presently available models and heat flux estimates, accuracy improvements in SST retrievals associated with better physical treatment of the near-surface layer were partially balanced by uncertainties in the models and extra required input data. While no significant accuracy improvement was observed in this experiment, the results are very encouraging for future applications where improved models and coincident environmental data will be available. These results are included in a manuscript undergoing final review with the Journal of Atmospheric and Oceanic Technology.

  13. Satellite Sensed Skin Sea Surface Temperature

    NASA Technical Reports Server (NTRS)

    Donlon, Craig

    1997-01-01

    Quantitative predictions of spatial and temporal changes the global climate rely heavily on the use of computer models. Unfortunately, such models cannot provide the basis for climate prediction because key physical processes are inadequately treated. Consequently, fine tuning procedures are often used to optimize the fit between model output and observational data and the validation of climate models using observations is essential if model based predictions of climate change are to be treated with any degree of confidence. Satellite Sea Surface Temperature (SST) observations provide high spatial and temporal resolution data which is extremely well suited to the initialization, definition of boundary conditions and, validation of climate models. In the case of coupled ocean-atmosphere models, the SST (or more correctly the 'Skin' SST (SSST)) is a fundamental diagnostic variable to consider in the validation process. Daily global SST maps derived from satellite sensors also provide adequate data for the detection of global patterns of change which, unlike any other SST data set, repeatedly extend into the southern hemisphere extra-tropical regions. Such data are essential to the success of the spatial 'fingerprint' technique, which seeks to establish a north-south asymmetry where warming is suppressed in the high latitude Southern Ocean. Some estimates suggest that there is a greater than 80% chance of directly detecting significant change (97.5 % confidence level) after 10-12 years of consistent global observations of mean sea surface temperature. However, these latter statements should be qualified with the assumption that a negligible drift in the observing system exists and that biases between individual instruments required to derive a long term data set are small. Given that current estimates for the magnitude of global warming of 0.015 K yr(sup -1) - 0.025 K yr(sup -1), satellite SST data sets need to be both accurate and stable if such a warming trend is to

  14. Ground surface temperature simulation for different land covers

    NASA Astrophysics Data System (ADS)

    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

  15. Global lake surface water temperatures from ATSR

    NASA Astrophysics Data System (ADS)

    MacCallum, Stuart; Merchant, Christopher J.; Layden, Aisling

    2013-04-01

    The ATSR Reprocessing for Climate - Lake (ARC-Lake) project applies optimal estimation (OE) retrievals and probabilistic cloud screening methods to provide lake surface water temperature (LSWT) estimates from the series of (Advanced) Along-Track Scanning Radiometers. This methodology is generic (i.e. applicable to all lakes) as variations in physical properties such as elevation, salinity, and atmospheric conditions are accounted for through the forward modelling of observed radiances. In the initial phases of ARC-Lake, LSWTs were obtained for 258 of Earth's largest lakes. In the final phase of the project, the dataset is extended by applying the OE methodology to smaller lakes, providing LSWT data from 1991 to 2012 for approximately 1000 lakes. In this presentation we will provide an overview of the ARC-Lake project, its publically available data products and some applications of these products.

  16. Middle Pliocene sea surface temperature variability

    USGS Publications Warehouse

    Dowsett, H.J.; Chandler, M.A.; Cronin, T. M.; Dwyer, G.S.

    2005-01-01

    Estimates of sea surface temperature (SST) based upon foraminifer, diatom, and ostracod assemblages from ocean cores reveal a warm phase of the Pliocene between about 3.3 and 3.0 Ma. Pollen records and plant megafossils, although not as well dated, show evidence for a warmer climate at about the same time. Increased greenhouse forcing and altered ocean heat transport are the leading candidates for the underlying cause of Pliocene global warmth. Despite being a period of global warmth, this interval encompasses considerable variability. Two new SST reconstructions are presented that are designed to provide a climatological error bar for warm peak phases of the Pliocene and to document the spatial distribution and magnitude of SST variability within the mid-Pliocene warm period. These data suggest long-term stability of low-latitude SST and document greater variability in regions of maximum warming. Copyright 2005 by the American Geophysical Union.

  17. Sea surface temperatures from VAS MSI data

    NASA Technical Reports Server (NTRS)

    Bates, J. J.

    1984-01-01

    A procedure is developed for estimating sea surface temperatures from multispectral image data acquired from the VISSR atmospheric sounder on the geostationary GOES satellites. Theoretical regression equations for two and three infrared window channels are empirically tuned using clear field of view satellite radiances matched with reports of SST from NOAA fixed environmental buoys. The empirical regression equations are then used to produce daily regional analyses of SST. Monthly mean SST's for the western North Atlantic and the eastern equatorial Pacific during March and July 1982 were produced for use in the SST Intercomparison Workshop Series. Workshop results showed VAS SST's have a scatter of 0.8-1.0 C and a slight warm bias with respect to the other measurements of SST. The VAS SST's show no discernible bias in the region of El Chichon volcanic aerosol cloud.

  18. Space-Time Characteristics of Rainfall Diurnal Variations

    NASA Technical Reports Server (NTRS)

    Yang, Song; Kummerow, Chris; Olson, Bill; Smith, Eric A.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The space-time features of rainfall diurnal variation of precipitation are systematically investigated by using the Tropical Rainfall Measuring Mission (TRMM) precipitation products retrieved from TRMM microwave imager (TMI), precipitation radar (PR) and TMI/PR combined algorithms. Results demonstrate that diurnal variability of precipitation is obvious over tropical regions. The dominant feature of rainfall diurnal cycle over, ocean is that there is consistent rainfall peak in early morning, while there is a consistent rainfall peak in mid-late afternoon over land. The seasonal variation on intensity of rainfall diurnal cycle is clearly evidenced. Horizontal distributions of rainfall diurnal variations indicate that there is a clearly early-morning peak with a secondary peak in the middle-late afternoon in ocean rainfall at latitudes dominated by large-scale convergence and deep convection. There is also an analogous early-morning peak in land rainfall along with a stronger afternoon peak forced by surface heating. Amplitude analysis shows that the patterns and its evolution of rainfall diurnal cycle are very close to rainfall distribution pattern and its evolution. These results indicate that rainfall diurnal variations are strongly associated with large-scale convective systems and climate weather systems. Phase studies clearly present the regional and seasonal features of rainfall diurnal activities. Further studies on convective and stratiform rainfall show different characteristics of diurnal cycles. Their spatial and temporal variations of convective and stratiform rainfall indicate that mechanisms for rainfall diurnal variations vary with time and space.

  19. Sensitivity of Initial Conditions on Diurnal Variability of Indian Summer Monsoon

    NASA Astrophysics Data System (ADS)

    Das, Sukanta Kumar; Deb, Sanjib Kumar; Kishtawal, C. M.; Pal, Pradip Kumar

    2015-10-01

    The diurnal cycle of different surface parameters, viz. surface air temperature, surface pressure, and rain intensities, simulated by the Community Atmosphere Model (CAM) in the operational seasonal forecast of ISM-2012 using initial conditions (ICs) taken at synoptic hours of the day has been examined and compared with observations. Four members were simulated with ICs at 0000, 0600, 1200, and 1800 UTC on 1 August 2012. The impact of the initial conditions at the synoptic hours of the day was more visible over the landmass compared with the oceanic regions. The diurnal variation of the surface temperature in the model simulation showed the major features when compared with the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis except for the warm pool of northwest India and the Tibetan region. The surface pressure in the ECMWF reanalysis showed the semidiurnal cycle with two peaks at 0600 UTC and 1800 UTC; however, the range of the cycle was underestimated by the model simulation, showing only one peak at 0600 UTC. Significant variations in the diurnal cycle of rain intensities were seen among the different members. The model captured the diurnal cycle as the positive and negative peaks at 1200 and 0000 UTC with intensities at the peaks ~0.5 mm high and low, respectively, in the model simulation when compared with the observations. Presently, the seasonal forecast of ISM is generated through ensemble CAM experiments using different ICs taken from different dates but all at 0000 UTC. Consideration of ICs at different times of the day will add different ranges of diurnal variations in all the surface parameters within the family of ensemble members and also increase the number of members in the family. Indeed, these improve the ensemble processes in generating the seasonal forecast of ISM.

  20. Low Temperature Surface Carburization of Stainless Steels

    SciTech Connect

    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

  1. Calibration of a distributed hydrological model using satellite data of land surface temperature

    NASA Astrophysics Data System (ADS)

    Corbari, Chiara; Mancini, Marco; Ravazzani, Giovanni

    2013-04-01

    Calibration and validation of distributed models at basin scale generally refer to external variables, which are integrated catchment model outputs, and usually depend on the comparison between simulated and observed discharges at the available rivers cross sections, which are usually very few. However distributed models allow an internal validation due to their intrinsic structure, so that internal processes and variables of the model can be controlled in each cell of the domain. In particular this work investigates the potentiality to control evapotranspiration and its spatial and temporal variability through the detection of land surface temperature (LST) from satellite remote sensing. This study proposes a methodology for the calibration of distributed hydrological models at basin scale using remote sensing data of land surface temperature. The distributed energy water balance model, Flash-flood Event-based Spatially-distributed rainfall-runoff Transformation - Energy Water Balance model (FEST-EWB) will be calibrated in the Upper Po river basin (Italy) closed at the river cross section of Ponte della Becca with a total catchment area of about 38000 km2. The model algorithm solves the system of energy and mass balances in term of the representative pixel equilibrium temperature (RET) that governs the fluxes of energy and mass over the basin domain. This equilibrium surface temperature, which is a critical model state variable, is comparable to the land surface temperature (LST) from satellite. So a pixel to pixel semi-automatic calibration procedure of soil and vegetation parameter is presented through the comparison between the model internal state variable RET and the remotely observed LST. A similar calibration procedure will also be applied performing the traditional calibration using only discharge measurements. 260 diurnal and nocturne LST MODIS products are compared with FEST-EWB land surface temperature over the 11 years of simulation from 2000 to 2010

  2. Comparison of model land skin temperature with remotely sensed estimates and assessment of surface-atmosphere coupling

    NASA Astrophysics Data System (ADS)

    Trigo, I. F.; Boussetta, S.; Viterbo, P.; Balsamo, G.; Beljaars, A.; Sandu, I.

    2015-12-01

    The coupling between land surface and the atmosphere is a key feature in Earth System Modeling for exploiting the predictability of slowly evolving geophysical variables (e.g., soil moisture or vegetation state), and for correctly representing rapid variations within the diurnal cycle, particularly relevant in data assimilation applications. In this study, land surface temperature (LST) estimated from Meteosat Second Generation (MSG) is used to assess the European Centre for Medium-Range Weather Forecasts (ECMWF) skin temperature, which can be interpreted as a radiative temperature of the model surface. It is shown that the ECMWF model tends to slightly overestimate skin temperature during nighttime and underestimate daytime values. Such underestimation of daily amplitudes is particularly pronounced in (semiarid) arid regions, suggesting a misrepresentation of surface energy fluxes in those areas. The LST estimated from MSG is used to evaluate the impact of changes in some of the ECMWF model surface parameters. The introduction of more realistic model vegetation is shown to have a positive but limited impact on skin temperature: long integration leads to an equilibrium state where changes in the latent heat flux and soil moisture availability compensate each other. Revised surface roughness lengths for heat and momentum, however, lead to overall positive impact on daytime skin temperature, mostly due to a reduction of sensible heat flux. This is particularly relevant in nonvegetated areas, unaffected by model vegetation. The reduction of skin conductivity, a parameter which controls the heat transfer to ground by diffusion, is shown to further improve the model skin temperature.

  3. Towards Monitoring Satellite Land Surface Temperature Production

    NASA Astrophysics Data System (ADS)

    Yu, P.; Yu, Y.; Liu, Y.; Wang, Z.; Zhang, X.

    2014-12-01

    Land surface temperature (LST) is of fundamental importance to the net radiation budget at the Earth surface and to monitoring the state of crops and vegetation, as well as an important indicator of both the greenhouse effect and the energy flux between the atmosphere and the land. Since its launch on October 28, 2011, the Suomi National Polar-orbiting Partnership (S-NPP) satellite has been continuously providing data for LST production; intensive validation and calibration of the LST data have been conducted since then. To better monitor the performance of the S-NPP LST product and evaluate different retrieval algorithms for potential improvement, a near-real-time monitoring system has been developed and implemented. The system serves as a tool for both the routine monitoring and the deep-dive researches. It currently consists of two major components: the global cross-satellite LST comparisons between S-NPP/VIIRS and MODIS/AQUA, and the LST validation with respect to in-situ observations from SURFRAD network. Results about cross-satellite comparisons, satellite-in situ LST validation, and evaluation of different retrieval algorithms are routinely generated and published through an FTP server of the system ftp. The results indicate that LST from the S-NPP is comparable to that from MODIS. A few case studies using this tool will be analyzed and presented.

  4. Interpreting LRO Diviner surface temperatures: Modeling three-dimensional lunar regolith thermophysical properties

    NASA Astrophysics Data System (ADS)

    Williams, J.; Paige, D. A.; Vasavada, A. R.

    2010-12-01

    The Diviner Lunar Radiometer Experiment on NASA's Lunar Reconnaissance Orbiter has been mapping the global thermal state of the Moon since July of 2009. The instrument has acquired solar reflectance and thermal emission data in nine spectral channels spanning a wavelength range from 0.3 to 400 microns [1] revealing the extreme nature of the lunar thermal environment. Superposed on the large-scale trends due to latitude, time of day, and season, the surface temperature of the Moon can exhibit extreme spatial variations at length scales all the way down to that of the diurnal thermal skin depth (˜10 cm) due to the low thermal conductivity of the bulk of the regolith, the lack of an appreciable atmosphere, and the effects of slopes and shadowing [2]. Further, surface temperatures are highly sensitive to the thermophysical properties within the first few meters of the surface and thus spatial variations in density, thermal conductivity, heat capacity, albedo, and emissivity, will have an influence. This significantly complicates the interpretation of lunar thermal observations and thermal model results. To aid in our interpretation of Diviner data and model derived results, we are developing a 3-diminsional regolith model to better understand how variations both vertically and laterally of the thermophysical properties of the lunar regolith can affect Diviner observations. This extends previous 1-dimisional modeling efforts which included vertical layering [3] to now capture lateral variability in regolith properties which, in the lunar environment, can result in extreme thermal gradients over short length scales (10’s cm). The initial application of the model is to explore the sensitivity of the surface temperature throughout the diurnal cycle to rocks in the regolith. With no appreciable atmosphere to buffer surface temperatures, the nighttime environment is characterized by extreme cold with the sensible heat stored in the subsurface during the day being the only

  5. SMILES zonal and diurnal variation climatology of stratospheric and mesospheric trace gasses: O3, HCl, HNO3, ClO, BrO, HOCl, HO2, and temperature

    NASA Astrophysics Data System (ADS)

    Kreyling, Daniel; Sagawa, Hideo; Wohltmann, Ingo; Lehmann, Ralph; Kasai, Yasuko

    2013-10-01

    We present a climatology of the diurnal variation of short-lived atmospheric compounds, such as ClO, BrO, HO2, and HOCl, as well as longer-lived species: O3, the hydrogen chloride isotopes H35Cl and H37Cl, and HNO3. Measurements were taken by the Superconducting Submillimeter-wave Limb-Emission Sounder (SMILES). This spectrally resolving radiometer, with very low observation noise and altitude range from the lower stratosphere to the lower thermosphere (20-100km), was measuring vertical profiles of absorption spectra along a non-sun-synchronous orbit, thus observing at all local times. We used the retrieved volume mixing ratio profiles to compile climatologies that are a function of pressure, a horizontal coordinate (latitude or equivalent latitude), and a temporal coordinate (solar zenith angle or local solar time). The main product presented are climatologies with a high resolution of the temporal coordinate (diurnal variation climatologies). In addition, we provide climatologies with a high resolution of the horizontal coordinate (zonal climatologies).The diurnal variation climatologies are based on data periods of 2 months and the zonal climatologies on monthly data periods. Consideration of the SMILES time-space sampling patterns with respect to the averaging coordinates is a key issue for climatology creation, especially in case of diurnal variation climatologies. Biases induced by inhomogeneous sampling are minimized by carefully choosing the size of averaging bins. The sampling biases of the diurnal variation climatology of ClO and BrO are investigated in a comparison of homogeneously sampled model data versus SMILES-sampled model data from the stratospheric Lagrangian chemistry and transport model Alfred Wegener Institute Lagrangian Chemisrty/Transport System. In most cases, the relative sampling error is in the range of 0-20%. The strongest impact of sampling biases is found where the species' temporal gradients are strongest (mostly at sunrise and sunset

  6. Temperature distribution along the surface of evaporating droplets.

    PubMed

    Zhang, Kai; Ma, Liran; Xu, Xuefeng; Luo, Jianbin; Guo, Dan

    2014-03-01

    The surface temperature can significantly affect the flow field of drying droplets. Most previous studies assumed a monotonic temperature variation along the droplet surface. However, the present analyses indicate that a nonmonotonic spatial distribution of the surface temperature should occur. Three different patterns of the surface temperature distribution may appear during the evaporation process of liquid droplets: (i) the surface temperature increases monotonically from the center to the edge of the droplet; (ii) the surface temperature exhibits a nonmonotonic spatial distribution along the droplet surface; (iii) the surface temperature decreases monotonically from the center to the edge of the droplet. These surface temperature distributions can be explained by combining the evaporative cooling at the droplet surface and the heat conduction across the substrate and the liquid. Furthermore, a "phase diagram" for the distribution of the surface temperature is introduced and the effect of the spatial temperature distribution along the droplet surface on the flow structure of the droplet is discussed. The results may provide a better understanding of the Marangoni effect of drying droplets and provide a potential way to control evaporation-driven deposition as well as the assembly of colloids and other materials. PMID:24730849

  7. Diurnal variations of Titan

    NASA Astrophysics Data System (ADS)

    Cui, J.; Galand, M.; Yelle, R. V.; Vuitton, V.; Wahlund, J.-E.; Lavvas, P. P.; Mueller-Wodarg, I. C. F.; Kasprzak, W. T.; Waite, J. H.

    2009-04-01

    We present our analysis of the diurnal variations of Titan's ionosphere (between 1,000 and 1,400 km) based on a sample of Ion Neutral Mass Spectrometer (INMS) measurements in the Open Source Ion (OSI) mode obtained from 8 close encounters of the Cassini spacecraft with Titan. Though there is an overall ion depletion well beyond the terminator, the ion content on Titan's nightside is still appreciable, with a density plateau of ~700 cm-3 below ~1,300 km. Such a plateau is associated with the combination of distinct diurnal variations of light and heavy ions. Light ions (e.g. CH5+, HCNH+, C2H5+) show strong diurnal variation, with clear bite-outs in their nightside distributions. In contrast, heavy ions (e.g. c-C3H3+, C2H3CNH+, C6H7+) present modest diurnal variation, with significant densities observed on the nightside. We propose that the distinctions between light and heavy ions are associated with their different chemical loss pathways, with the former primarily through "fast" ion-neutral chemistry and the latter through "slow" electron dissociative recombination. The INMS data suggest day-to-night transport as an important source of ions on Titan's nightside, to be distinguished from the conventional scenario of auroral ionization by magnetospheric particles as the only ionizing source on the nightside. This is supported by the strong correlation between the observed night-to-day ion density ratios and the associated ion lifetimes. We construct a time-dependent ion chemistry model to investigate the effects of day-to-night transport on the ionospheric structures of Titan. The predicted diurnal variation has similar general characteristics to those observed, with some apparent discrepancies which could be reconciled by imposing fast horizontal thermal winds in Titan's upper atmosphere.

  8. Diurnal Wind Regimes and Lapse-Rate Variability Over Clean and Debris-Covered Ice

    NASA Astrophysics Data System (ADS)

    Flowers, G. E.; Young, E.

    2015-12-01

    Near-surface winds and air temperature play an important role in the surface energy balance of glaciers and ice sheets, and can be highly variable in space and time. The increasing fraction of debris-covered ice observed in many retreating alpine glacier environments motivates the study of these variables, and the processes that control them, over both clean and debris-covered ice. We use meteorological data collected in the ablation zone of a ~ 5km-long valley glacier in Yukon, Canada, to analyze the diurnal variability of temperature and wind regimes over debris-covered and debris-free ice. Our data reveal pronounced diurnal cycles in temperature lapse rates, wind speeds, and wind directions. Common to both clean and debris-covered areas are: (1) a shallowing of lapse rates in the early morning from 6:00 to 9:00 and a steepening of lapse rates during the day from 9:00 to 16:00, (2) nearly identical lapse rates regardless of surface type between 15:00 and 19:00, and (3) a persistent diurnal wind regime in which up-valley winds occur from late morning to evening, peaking at 16:00-17:00, and relatively weaker down-valley winds occur overnight. Significant differences between the clean-ice and debris-covered sites are also evident in the data, namely: (1) much steeper night-time lapse rates over debris-covered ice than clean ice, (2) the occurrence of steepest lapse rates overnight for debris-covered ice and in late afternoon (around 16:00) for clean ice, and (3) a more pronounced diurnal cycle in windspeed over debris-covered ice than clean ice, despite all stations exhibiting evidence of the diurnal changes in wind direction. The patterns described above conform to a model of weak katabatic flow at night and relatively stronger up-valley winds during the day, peaking in late afternoon. Though absolute temperatures over clean and debris-covered ice are markedly different during the day, lapse rates over both surfaces evolve similarly through the day to achieve steep

  9. In situ validation of sea surface temperatures from the GCOM-W1 AMSR2 RSS calibrated brightness temperatures

    NASA Astrophysics Data System (ADS)

    Gentemann, Chelle L.; Hilburn, Kyle A.

    2015-05-01

    Remote Sensing Systems AMSR2 v7.2 data from 25 July 2012 to 9 October 2014 are collocated with in situ sea surface temperature (SST) data. The RSS SST algorithm uses AMSR2 brightness temperatures calibrated using a methodology developed at RSS rather than using the standard JAXA AMSR2 product, which includes the JAXA calibration. The new RFI exclusion methodology used for the AMSR2 v7.2 data is described. Buoy data are quality controlled using an internal quality indicator. Daytime collocations with wind speeds of less than 6 m s-1 are excluded to avoid diurnal contamination of the results. A mean bias (AMSR2 minus in situ) of -0.04 K and standard deviation 0.55 K with 109,350 collocations is found. The geographical distribution of biases is investigated, with a small increase in biases found at higher latitudes. At lower SST the uncertainty increases and the bias. The dependencies of the bias and uncertainties on other geophysical variables are shown to be negligible. The time series of the bias and uncertainty show little variability, but a small seasonal dependence is determined to be related to a seasonal shift in wind speeds. Overall, the AMSR2 SSTs are of comparable quality to the AMSR-E SSTs and continue the climate microwave SST record that started in 1997.

  10. Diurnal variation of marine stratocumulus over San Nicolas Island during July 1987

    NASA Technical Reports Server (NTRS)

    Blaskovic, Miriam; Davies, Roger; Snider, J. B.

    1991-01-01

    A study is presented of surface measurements made at San Nicolas Island during the intensive field observation marine stratocumulus phase of the First International Satellite Cloud Climatology Program Regional Experiment, July 1987, to retrieve the average diurnal variation of marine stratocumulus and associated surface variables. The diurnal behavior of the cloud base appears to be consistent with model-predicted uncoupling of the cloud layer and the subcloud layer as the turbulent flux of moisture is limited by solar heating close to the cloud base. Also, variation in surface air temperature is consistent with the limitation of the turbulent flux of heat between the two layers, screening the surface from the effect of longwave cooling from the cloud top.

  11. Surface Temperature Measurement Using Hematite Coating

    NASA Technical Reports Server (NTRS)

    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.

  12. A multispectral method of determining sea surface temperatures

    NASA Technical Reports Server (NTRS)

    Shenk, W. E.

    1972-01-01

    A multispectral method for determining sea surface temperatures is discussed. The specifications of the equipment and the atmospheric conditions required for successful multispectral data acquisition are described. Examples of data obtained in the North Atlantic Ocean are presented. The differences between the actual sea surface temperatures and the equivalent blackbody temperatures as determined by a radiometer are plotted.

  13. 30 CFR 18.23 - Limitation of external surface temperatures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Limitation of external surface temperatures. 18.23 Section 18.23 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING... and Design Requirements § 18.23 Limitation of external surface temperatures. The temperature of...

  14. 30 CFR 18.23 - Limitation of external surface temperatures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Limitation of external surface temperatures. 18.23 Section 18.23 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING... and Design Requirements § 18.23 Limitation of external surface temperatures. The temperature of...

  15. 30 CFR 18.23 - Limitation of external surface temperatures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Limitation of external surface temperatures. 18.23 Section 18.23 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING... and Design Requirements § 18.23 Limitation of external surface temperatures. The temperature of...

  16. 30 CFR 18.23 - Limitation of external surface temperatures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Limitation of external surface temperatures. 18.23 Section 18.23 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING... and Design Requirements § 18.23 Limitation of external surface temperatures. The temperature of...

  17. 30 CFR 18.23 - Limitation of external surface temperatures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Limitation of external surface temperatures. 18.23 Section 18.23 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING... and Design Requirements § 18.23 Limitation of external surface temperatures. The temperature of...

  18. Technique for the estimation of surface temperatures from embedded temperature sensing for rapid, high energy surface deposition.

    SciTech Connect

    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.

  19. Prediction of Ground Surface Temperature and Soil Moisture Content by the Force-Restore Method

    NASA Astrophysics Data System (ADS)

    Hu, Zhenglin; Islam, Shafiqul

    1995-10-01

    The parsimony and computational efficiency offered by the force-restore approximation of the diffusion equation have motivated its widespread application in modeling ground surface temperature. Different assumptions regarding the definition of ground surface temperature have resulted in different versions of the force-restore method. Here, four existing versions of the force-restore method for ground surface temperature are compared and contrasted. An improved version of the force-restore method is developed by minimizing the error produced by the force-restore approximation of the heat diffusion equation. The proposed model performs well for the physically realistic ranges of scaled soil thickness and reproduces amplitude and phase that are quite close to the exact solution of the diffusion equation under a single periodic forcing. It is shown that neglect of higher harmonics can produce appreciable errors in the force-restore method if the upper soil thickness is less than the damping depth of the diurnal forcing. The success of the force-restore approximation in modeling ground surface temperature has prompted its application in the prediction of soil moisture content. However, extension of the force-restore method for the prediction of soil moisture content is not straightforward. There are two major difficulties in modeling soil moisture content by the force-restore method. One is the situation-dependent relative importance of the suction term and gravity term in the Richards equation and the other is the choice of state variable, moisture content versus suction head, in the solution of the force-restore method for soil moisture prediction. Both of these could produce appreciable errors in the force-restore treatment of soil moisture evolution.

  20. Inferring pathogen inactivation from the surface temperatures of compost heaps.

    PubMed

    Turner, Claire; Williams, Adrian; White, Rodger; Tillett, Robin

    2005-03-01

    A sufficiently high composting temperature should inactivate many common pathogens likely to be present in solid animal waste. Monitoring core temperatures inside compost heaps is not straightforward, which means that heaps are not generally monitored. An alternative is to monitor surface temperatures and use those data to infer core temperatures, and thus whether pathogen inactivation has occurred. This paper describes two methods (thermal imaging and thermocouples) for the measurement of surface temperature, and a modelling approach using time series analysis to predict the temperatures obtained in the core of aerated heaps of composting pig farmyard manure (FYM) from surface temperature data. The model was able to predict core temperatures in the heap quite closely for a period of time for well insulated parts of the heap, although predictions were further from observed values close to the surface of the heap and the aeration pipe. PMID:15501657

  1. Mars Science Laboratory diurnal moisture observations and column simulations

    NASA Astrophysics Data System (ADS)

    Savijärvi, H. I.; Harri, A.-M.; Kemppinen, O.

    2015-05-01

    Hourly observations of air temperature and relative humidity at 1.6 m height from the surface (T 1.6 m, RH 1.6 m) measured by the Mars Science Laboratory (MSL) Rover Environmental Monitoring Station relative humidity (REMS-H) device are shown for MSL solar days 15-17 and 80-82, augmented with column model simulations. The diurnal range of T 1.6 m was 197-268 K in the first period, RH 1.6 m being small (<1%) in daytime but increasing to 45-49% by sunrise. During the warmer second period the T 1.6 m range was 201-275 K with RH 1.6 m only up to 16% in the morning. The modeled temperatures were quite close to those observed when the local albedo was set to 0.15 and thermal inertia to 300 tiu. The modeled RH 1.6 m was close to that observed when the well-mixed boundary layer values (0-4 km) of the mass mixing ratio q were 28-30 ppmm (suggesting a precipitable water content (PWC) of ~5.5 µm) during the first period and 12 ppmm (PWC of ~2 µm) during the second period. The REMS-H observations indicate systematic diurnal variation in the near-surface mixing ratio.

  2. A diurnal animation of thermal images from a day-night pair

    USGS Publications Warehouse

    Watson, K.

    2000-01-01

    Interpretation of thermal images is often complicated because the physical property information is contained in both the spatial and temporal variations of the data and thermal models are necessary to extract and display this information. A linearized radiative transfer solution to the surface flux has been used to derive a function that is invariant with respect to thermal inertia. This relationship makes it possible to predict the temperature variation at any time in the diurnal cycle using only two distinct measurements (e.g., noon and midnight). An animation can then be constructed from a pair of day-night images to view both the spatial and temporal temperature changes throughout the diurnal cycle. A more complete solution for the invariant function, using the method of Laplace transforms and based on the linearized solution, was introduced. These results indicate that the linear model does not provide a sufficiently accurate estimate. Using standard conditions (latitude 30??, solar declination 0??, acquisition times at noon and midnight), this new relationship was used to predict temperature throughout the diurnal cycle to an rms error of 0.2??C, which is close to the system noise of most thermal scanners. The method was further extended to include the primary effects of topographic slope with similar accuracy. The temperature was computed at 48 equally spaced times in the diurnal cycle with this algorithm using a co-registered day and night TIMS (Thermal Infrared Multispectral Scanner) data pair (330 pixels, 450 lilies) acquired of the Carlin, Nevada, area and a co-registered DEM (Digital Elevation Model). (Any reader can view the results by downloading the animation file from an identified tip site). The results illustrate the power of animation to display subtle temporal and spatial temperature changes, which can provide clues to structural controls and material property differences. This 'visual change' approach could significantly increase the use of

  3. Ice surface temperatures: seasonal cycle and daily variability from in-situ and satellite observations

    NASA Astrophysics Data System (ADS)

    Madsen, Kristine S.; Dybkjær, Gorm; Høyer, Jacob L.; Nielsen-Englyst, Pia; Rasmussen, Till A. S.; Tonboe, Rasmus T.

    2016-04-01

    Surface temperature is an important parameter for understanding the climate system, including the Polar Regions. Yet, in-situ temperature measurements over ice- and snow covered regions are sparse and unevenly distributed, and atmospheric circulation models estimating surface temperature may have large biases. To change this picture, we will analyse the seasonal cycle and daily variability of in-situ and satellite observations, and give an example of how to utilize the data in a sea ice model. We have compiled a data set of in-situ surface and 2 m air temperature observations over land ice, snow, sea ice, and from the marginal ice zone. 2523 time series of varying length from 14 data providers, with a total of more than 13 million observations, have been quality controlled and gathered in a uniform format. An overview of this data set will be presented. In addition, IST satellite observations have been processed from the Metop/AVHRR sensor and a merged analysis product has been constructed based upon the Metop/AVHRR, IASI and Modis IST observations. The satellite and in-situ observations of IST are analysed in parallel, to characterize the IST variability on diurnal and seasonal scales and its spatial patterns. The in-situ data are used to estimate sampling effects within the satellite observations and the good coverage of the satellite observations are used to complete the geographical variability. As an example of the application of satellite IST data, results will be shown from a coupled HYCOM-CICE ocean and sea ice model run, where the IST products have been ingested. The impact of using IST in models will be assessed. This work is a part of the EUSTACE project under Horizon 2020, where the ice surface temperatures form an important piece of the puzzle of creating an observationally based record of surface temperatures for all corners of the Earth, and of the ESA GlobTemperature project which aims at applying surface temperatures in models in order to

  4. Temperature dependent droplet impact dynamics on flat and textured surfaces

    SciTech Connect

    Azar Alizadeh; Vaibhav Bahadur; Sheng Zhong; Wen Shang; Ri Li; James Ruud; Masako Yamada; Liehi Ge; Ali Dhinojwala; Manohar S Sohal

    2012-03-01

    Droplet impact dynamics determines the performance of surfaces used in many applications such as anti-icing, condensation, boiling and heat transfer. We study impact dynamics of water droplets on surfaces with chemistry/texture ranging from hydrophilic to superhydrophobic and across a temperature range spanning below freezing to near boiling conditions. Droplet retraction shows very strong temperature dependence especially for hydrophilic surfaces; it is seen that lower substrate temperatures lead to lesser retraction. Physics-based analyses show that the increased viscosity associated with lower temperatures can explain the decreased retraction. The present findings serve to guide further studies of dynamic fluid-structure interaction at various temperatures.

  5. Modes of variability of global sea surface temperature, free atmosphere temperature and oceanic surface energy flux

    SciTech Connect

    Hu, Wenjie; Newell, R.E.; Wu, Zhong-Xiang

    1994-11-01

    Monthly mean sea surface temperature (SST), free air temperature from satellite microwave sounding units (MSU) and oceanic surface energy fluxes are subjected to empirical orthogonal function (EOF) analysis for a common decade to investigate the physical relationships involved. The first seasonal modes of surface solar energy flux and SST show similar inter-hemispheric patterns with an annual cycle. Solar flux appears to control this pattern of SST. The first seasonal mode of MSU is similar with, additionally, land-sea differences; MSU is apparently partly controlled by absorption of solar near-infrared radiation and partly by sensible heat from from the land surface. The second and third seasonal eigenvector of SST and solar flux exhibit semi-annual oscillations associated with a pattern of cloudiness in the subtropics accompanying the translation of the Hadley cell rising motion between the hemispheres. The second seasonal mode of MSU is dominated by an El Nino Signal. The first nonseasonal EOFs of SST and solar flux exhibit El Nino characteristics with solar pattern being governed by west-to-east translation of a Walker cell type pattern. The first non-seasonal EOF of MSU shows a tropical strip pattern for the El Nino mode, which is well correlated with the latent heat fluxes in the tropical east Pacific but not in the tropical west Pacific. Two possible explanations are: an increase in subsidence throughout the tropical strip driven by extra evaporation in the tropical east Pacific and consequent additional latent heat liberation; a decrease of meridional heat flux out of the tropics. 56 refs., 12 figs., 5 tabs.

  6. Temperature sensitive surfaces and methods of making same

    DOEpatents

    Liang, Liang [Richland, WA; Rieke, Peter C [Pasco, WA; Alford, Kentin L [Pasco, WA

    2002-09-10

    Poly-n-isopropylacrylamide surface coatings demonstrate the useful property of being able to switch charateristics depending upon temperature. More specifically, these coatings switch from being hydrophilic at low temperature to hydrophobic at high temperature. Research has been conducted for many years to better characterize and control the properties of temperature sensitive coatings. The present invention provides novel temperature sensitive coatings on articles and novel methods of making temperature sensitive coatings that are disposed on the surfaces of various articles. These novel coatings contain the reaction products of n-isopropylacrylamide and are characterized by their properties such as advancing contact angles. Numerous other characteristics such as coating thickness, surface roughness, and hydrophilic-to-hydrophobic transition temperatures are also described. The present invention includes articles having temperature-sensitve coatings with improved properties as well as improved methods for forming temperature sensitive coatings.

  7. Validation of Surface Skin Temperature and Moisture Profiles Using Satellite Data

    NASA Technical Reports Server (NTRS)

    Wu, Man Li C.; Schubert, Siegfried; Lin, Ching I.

    1999-01-01

    New validation techniques and metrics using satellite data have been developed to evaluate the quality of model-based estimates of surface skin temperature (Tg) and moisture profiles (q). The satellite data consist of clear sky outgoing long-wave radiation (CLR), broadband radiances from 8 to 12 mu (RadWn), brightness temperature centered around 10.8 mu (Tbb), and total precipitable water (TPW) from microwave radiometry. We show that CLR can be used to diagnose Tg. Furthermore, by using a combination of CLR and RadWn from CERES-TRMM measurements and TPW from SSM/I, we are able to identify errors in the moisture profile. Finally, three-hourly Tbb from the International Satellite Cloud Climatology Project can be used to evaluate the amplitude and diurnal variation of Tg. For purpose of illustration, Tg and q are evaluated from runs with an early version of the Goddard Earth Observing System Data Assimilation System (GEOS-2). It is found that, in general, Tg is too cold in the winter hemisphere and q is too wet in the upper atmosphere. In order to address these deficiencies, several improvements have been implemented into GEOS-2, including a Land-Surface-Model, a Moist Turbulence Scheme, and the assimilation of new TOVS retrievals. Preliminary results indicate positive impacts from each of these implementations.

  8. Using Daily Ocean Wind Vector and Speed Measurements to Estimate the Diurnal Cycle Modes

    NASA Astrophysics Data System (ADS)

    Turk, F. J.; Hristova-Veleva, S. M.; Haddad, Z. S.

    2014-12-01

    Over many oceanic regions, the surface wind varies widely throughout the day, owing to various meteorological forcings, such as land/sea temperature differences near coasts, or variations associated with tropical precipitation processes. Over the tropical oceans, several coarsely spaced buoy networks (TAO/TRITON in the Pacific, PIRATA in the Atlantic, RAMA in the Indian Ocean) are maintained as part of the Global Tropical Moored Buoy Array. For finer global scale analysis, further improvements to the modeling and understanding of physical processes within the coupled atmosphere ocean is based upon analysis of a disparate collection of low Earth orbiting (LEO) satellite based ocean surface wind data records. Since LEO satellite observations represent intermittently spaced, instantaneous snapshots, sampling against the backdrop of continuously changing physical processes, its is important to carefully merge and analyze the multiple satellite datasets in order to extract meaningful information on diurnal and semi-diurnal wind cycles. Early analysis of an investigation are described whereby multi-year collections of global sun-synchronous and asynchronous orbiting satellite ocean wind data are used to investigate the diurnal and semi-diurnal ocean wind vector variability over certain regions. A unique feature of the effort is the utilization of all capable sensors, including both wind speed and wind vector capable sensors, using overlapping asynchronous satellite observations to establish self-consistency, including inter-sensor bias correction to a common reference platform.

  9. Estimation of Surface Air Temperature Over Central and Eastern Eurasia from MODIS Land Surface Temperature

    NASA Technical Reports Server (NTRS)

    Shen, Suhung; Leptoukh, Gregory G.

    2011-01-01

    Surface air temperature (T(sub a)) 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 T(sub a) from satellite remotely sensed land surface temperature (T(sub s)) by using MODIS-Terra data over two Eurasia regions: northern China and fUSSR. High correlations are observed in both regions between station-measured T(sub a) and MODIS T(sub s). The relationships between the maximum T(sub a) and daytime T(sub s) depend significantly on land cover types, but the minimum T(sub a) and nighttime T(sub s) have little dependence on the land cover types. The largest difference between maximum T(sub a) and daytime T(sub s) appears over the barren and sparsely vegetated area during the summer time. Using a linear regression method, the daily maximum T(sub a) were estimated from 1 km resolution MODIS T(sub s) under clear-sky conditions with coefficients calculated based on land cover types, while the minimum T(sub a) were estimated without considering land cover types. The uncertainty, mean absolute error (MAE), of the estimated maximum T(sub a) 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.

  10. Ultra Low Temperature Ultra Low Power Instrument Packages for Planetary Surfaces

    NASA Technical Reports Server (NTRS)

    Clark, P. E.; Millar, P. S.; Beaman, B.; Yeh, P. S.; Cooper, L.; Feng, S.; Young, E.

    2010-01-01

    Achievement of solar system exploration roadmap goals will involve robotic or human deployment and longterm operation of surface science packages remote from human presence, thus requiring autonomous, self-powered operation. The major challenge such packages face will be operating during long periods of darkness in extreme cold potentially without the Pu238 based power and thermal systems available to Apollo era packages (ALSEP). Development of such science payloads will thus require considerable optimization of instrument and subsystem design, packaging and integration for a variety of planetary surface environments in order to support solar system exploration fully. Our work supports this process through the incorporation of low temperature operational components and design strategies which radically minimize power, mass, and cost while maximizing the performance under extreme surface conditions that are in many cases more demanding than those routinely experienced by spacecraft in deep space. Chief instruments/instrument package candidates include those which could provide long-term monitoring of the surface and subsurface environments for fundamental science and human crew safety. The initial attempt to design a 10 instrument environmental monitoring package with a solar/battery based power system led to a package with a unacceptably large mass (500 kg) of which over half was battery mass. In phase 1, a factor of 5 reduction in mass was achieved, first through the introduction of high performance electronics capable of operating at far lower temperature and then through the use of innovative thermal balance strategies involving the use of multi-layer thin materials and gravity-assisted heat pipes. In phase 2, reported here, involves strategies such as universal incorporation of ULT/ULP digital and analog electronics, and distributed or non-conventionally packaged power systems. These strategies will be required to meet the far more challenging thermal

  11. Estimation of Surface Heat Flux and Surface Temperature during Inverse Heat Conduction under Varying Spray Parameters and Sample Initial Temperature

    PubMed Central

    Aamir, Muhammad; Liao, Qiang; Zhu, Xun; Aqeel-ur-Rehman; Wang, Hong

    2014-01-01

    An experimental study was carried out to investigate the effects of inlet pressure, sample thickness, initial sample temperature, and temperature sensor location on the surface heat flux, surface temperature, and surface ultrafast cooling rate using stainless steel samples of diameter 27 mm and thickness (mm) 8.5, 13, 17.5, and 22, respectively. Inlet pressure was varied from 0.2 MPa to 1.8 MPa, while sample initial temperature varied from 600°C to 900°C. Beck's sequential function specification method was utilized to estimate surface heat flux and surface temperature. Inlet pressure has a positive effect on surface heat flux (SHF) within a critical value of pressure. Thickness of the sample affects the maximum achieved SHF negatively. Surface heat flux as high as 0.4024 MW/m2 was estimated for a thickness of 8.5 mm. Insulation effects of vapor film become apparent in the sample initial temperature range of 900°C causing reduction in surface heat flux and cooling rate of the sample. A sensor location near to quenched surface is found to be a better choice to visualize the effects of spray parameters on surface heat flux and surface temperature. Cooling rate showed a profound increase for an inlet pressure of 0.8 MPa. PMID:24977219

  12. Estimation of surface heat flux and surface temperature during inverse heat conduction under varying spray parameters and sample initial temperature.

    PubMed

    Aamir, Muhammad; Liao, Qiang; Zhu, Xun; Aqeel-ur-Rehman; Wang, Hong; Zubair, Muhammad

    2014-01-01

    An experimental study was carried out to investigate the effects of inlet pressure, sample thickness, initial sample temperature, and temperature sensor location on the surface heat flux, surface temperature, and surface ultrafast cooling rate using stainless steel samples of diameter 27 mm and thickness (mm) 8.5, 13, 17.5, and 22, respectively. Inlet pressure was varied from 0.2 MPa to 1.8 MPa, while sample initial temperature varied from 600°C to 900°C. Beck's sequential function specification method was utilized to estimate surface heat flux and surface temperature. Inlet pressure has a positive effect on surface heat flux (SHF) within a critical value of pressure. Thickness of the sample affects the maximum achieved SHF negatively. Surface heat flux as high as 0.4024 MW/m(2) was estimated for a thickness of 8.5 mm. Insulation effects of vapor film become apparent in the sample initial temperature range of 900°C causing reduction in surface heat flux and cooling rate of the sample. A sensor location near to quenched surface is found to be a better choice to visualize the effects of spray parameters on surface heat flux and surface temperature. Cooling rate showed a profound increase for an inlet pressure of 0.8 MPa. PMID:24977219

  13. Influence of lunar topography on simulated surface temperature

    NASA Astrophysics Data System (ADS)

    Zhiguo, Meng; Yi, Xu; Zhanchuan, Cai; Shengbo, Chen; Yi, Lian; Hang, Huang

    2014-11-01

    The surface temperature of the Moon is one of the essential parameters for the lunar exploration, especially to evaluate the Moon thermophysical features. The distribution of the temperature is heavily influenced by the Moon topography, which, however, is rarely studied in the state-of-art surface temperature models. Therefore, this paper takes the Moon topography into account to improve the surface temperature model, Racca model. The main parameters, such as slopes along the longitude and latitude directions, are estimated with the topography data from Chang'E-1 satellite and the Horn algorithm. Then the effective solar illumination model is then constructed with the slopes and the relative position to the subsolar point. Finally, the temperature distribution over the Moon surface is obtained with the effective illumination model and the improved Racca model. The results indicate that the distribution of the temperature is very sensitive to the fluctuation of the Moon surface. The change of the surface temperature is up to 150 K in some places compared to the result without considering the topography. In addition, the variation of the surface temperature increases with the distance from the subsolar point and the elevation, along both latitude and longitude directions. Furthermore, the simulated surface temperature coincides well with the brightness temperature in 37 GHz observed by the microwave sounder onboard Chang'E-2 satellite. The corresponded emissivity map not only eliminates the influence of the topography, but also hints the inherent properties of the lunar regolith just below the surface. Last but not the least, the distribution of the permanently shadowed regions (PSRs) in the lunar pole area is also evaluated with the simulated surface temperature result.

  14. Sensitivity of nocturnal boundary layer temperature to tropospheric aerosol surface radiative forcing under clear-sky conditions

    NASA Astrophysics Data System (ADS)

    Nair, Udaysankar S.; McNider, Richard; Patadia, Falguni; Christopher, Sundar A.; Fuller, Kirk

    2011-01-01

    Since the middle of the last century, global surface air temperature exhibits an increasing trend, with nocturnal temperatures increasing at a much higher rate. Proposed causative mechanisms include the radiative impact of atmospheric aerosols on the nocturnal boundary layer (NBL) where the temperature response is amplified due to shallow depth and its sensitivity to potential destabilization. A 1-D version of the Regional Atmospheric Modeling System is used to examine the sensitivity of the nocturnal boundary layer temperature to the surface longwave radiative forcing (SLWRF) from urban aerosol loading and doubled atmospheric carbon dioxide concentrations. The analysis is conducted for typical midlatitude nocturnal boundary layer case days from the CASES-99 field experiment and is further extended to urban sites in Pune and New Delhi, India. For the cases studied, locally, the nocturnal SLWRF from urban atmospheric aerosols (2.7-47 W m-2) is comparable or exceeds that caused by doubled atmospheric carbon dioxide (3 W m-2), with the surface temperature response ranging from a compensation for daytime cooling to an increase in the nocturnal minimum temperature. The sensitivity of the NBL to radiative forcing is approximately 4 times higher compared to the daytime boundary layer. Nighttime warming or cooling may occur depending on the nature of diurnal variations in aerosol optical depth. Soil moisture also modulates the magnitude of SLWRF, decreasing from 3 to 1 W m-2 when soil saturation increases from 37% to 70%. These results show the importance of aerosols on the radiative balance of the climate system.

  15. Martian Meteorites Record Surface Temperatures on Mars

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2005-07-01

    Using published data for argon (Ar) released when Martian meteorites are heated, David Shuster (California Institute of Technology, now at Berkeley Geochronology Center, Berkeley, CA) and Benjamin Weiss (Massachusetts Institute of Technology) show that the nakhlite group of Martian meteorites and unique Martian meteorite ALH 84001 were probably not heated above about 0 degree C for most of their histories. This indicates that the surface of Mars has been cold for almost four billion years. If a warm, wet environment existed on Mars (inferred from previous studies of surface features and geochemical parameters), it occurred before four billion years ago.

  16. Snow surface temperature, radiative forcing and snow depth as determinants of snow density

    NASA Astrophysics Data System (ADS)

    Kirchner, P. B.; Painter, T. H.; Skiles, M.; Deems, J. S.

    2014-12-01

    Watershed scale observations of snow water equivalence (SWE) are becoming increasingly important globally as the quantity and timing of snowmelt has become less predictable. In the Colorado River watershed, where dust deposition can hasten snowmelt by several weeks, the need for these observations is critical. While advances in measuring snow depth and albedo from the NASA Airborne Snow Observatory have greatly improved our ability to constrain snow depth and radiative forcing, we have yet to develop a method for remotely observing snow density, which is required for calculating SWE. We evaluate measured and modeled variables of snow- infrared surface temperature, radiative forcing and snow depth as predictors of snow density. We use 10 seasons of in situ measured snow surface temperature, cumulative modeled dust in snow radiative forcing, snow depth and manually measured snow density from locations in the Rocky Mountains of southwestern Colorado. We also use measured snow depth and SWE from the 2013 and 2014 water years, from 23-35 locations stratified by modeled downwelling short wave radiation, and evaluate them as predictors of snow density. Our analysis shows that daily mean snow surface temperature (R2 0.61, p = <0.001) and cumulative radiative forcing (R2 0.54, p = <0.001) individually have significant coefficients of determination whereas snow depth alone was not significant. Multiple regression with all three variables (R2 0.84, p = <0.001) was the best predictor of density. Furthermore, when snowpack conditions were isothermal at 0° C, the diurnal coefficient of variation, of measured hourly surface temperature, exhibited consistently high variance. In 2013 we found significant correlations between spatially distributed measurements of snow density (R2 0.33, p = <0.001) and modeled downwelling short wave radiation. However, in 2014 the correlation was very low, supporting our hypothesis that seasonal differences in dust driven radiative forcing are also

  17. Diel Surface Temperature Range Scales with Lake Size.

    PubMed

    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

  18. Diel Surface Temperature Range Scales with Lake Size

    PubMed Central

    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

  19. Surface tension of low-temperature aqueous solutions

    SciTech Connect

    Horibe, A.; Fukusako, S.; Yamada, M.

    1996-03-01

    Measurements of the surface tension have been carried out to determine the effects of both temperature and concentration on the surface tension of aqueous solutions of sodium chloride, propylene glycol, and ethylene glycol. A differential capillary-rise method was employed for the measurements. The results show that the surface tension of the ethylene glycol solution and the propylene glycol solution increases as the concentration of the solution decreases, while for the sodium chloride solution the surface tension increases monotonically as the concentration increases. The surface tension of the liquids was found to be an almost-linear function of temperature from 20{degrees}C to just above the freezing temperature. Equations for the surface tension of the three binary aqueous solutions as a function of temperature and concentration are presented.

  20. Surface aerodynamic temperature modeling over rainfed cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration (ET) or latent heat flux (LE) can be spatially estimated as an energy balance (EB) residual for land surfaces using remote sensing inputs. The EB equation requires the estimation of net radiation (Rn), soil heat flux (G), and sensible heat flux (H). Rn and G can be estimated with ...

  1. Low temperature self-cleaning properties of superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Wang, Fajun; Shen, Taohua; Li, Changquan; Li, Wen; Yan, Guilong

    2014-10-01

    Outdoor surfaces are usually dirty surfaces. Ice accretion on outdoor surfaces could lead to serious accidents. In the present work, the superhydrophobic surface based on 1H, 1H, 2H, 2H-Perfluorodecanethiol (PFDT) modified Ag/PDMS composite was prepared to investigate the anti-icing property and self-cleaning property at temperatures below freezing point. The superhydrophobic surface was deliberately polluted with activated carbon before testing. It was observed that water droplet picked up dusts on the cold superhydrophobic surface and took it away without freezing at a measuring temperature of -10 °C. While on a smooth PFDT surface and a rough surface base on Ag/PDMS composite without PFDT modification, water droplets accumulated and then froze quickly at the same temperature. However, at even lower temperature of -12 °C, the superhydrophobic surface could not prevent the surface water from icing. In addition, it was observed that the frost layer condensed from the moisture pay an important role in determining the low temperature self-cleaning properties of a superhydrophobic surface.

  2. Possible rainfall reduction through reduced surface temperatures due to overgrazing

    NASA Technical Reports Server (NTRS)

    Otterman, J.

    1975-01-01

    Surface temperature reduction in terrain denuded of vegetation (as by overgrazing) is postulated to decrease air convection, reducing cloudiness and rainfall probability during weak meteorological disturbances. By reducing land-sea daytime temperature differences, the surface temperature reduction decreases daytime circulation of thermally driven local winds. The described desertification mechanism, even when limited to arid regions, high albedo soils, and weak meteorological disturbances, can be an effective rainfall reducing process in many areas including most of the Mediterranean lands.

  3. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2010 CFR

    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...

  4. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 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...

  5. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 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...

  6. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 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...

  7. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 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...

  8. Diurnally entrained anticipatory behavior in archaea.

    PubMed

    Whitehead, Kenia; Pan, Min; Masumura, Ken-ichi; Bonneau, Richard; Baliga, Nitin S

    2009-01-01

    By sensing changes in one or few environmental factors biological systems can anticipate future changes in multiple factors over a wide range of time scales (daily to seasonal). This anticipatory behavior is important to the fitness of diverse species, and in context of the diurnal cycle it is overall typical of eukaryotes and some photoautotrophic bacteria but is yet to be observed in archaea. Here, we report the first observation of light-dark (LD)-entrained diurnal oscillatory transcription in up to 12% of all genes of a halophilic archaeon Halobacterium salinarum NRC-1. Significantly, the diurnally entrained transcription was observed under constant darkness after removal of the LD stimulus (free-running rhythms). The memory of diurnal entrainment was also associated with the synchronization of oxic and anoxic physiologies to the LD cycle. Our results suggest that under nutrient limited conditions halophilic archaea take advantage of the causal influence of sunlight (via temperature) on O(2) diffusivity in a closed hypersaline environment to streamline their physiology and operate oxically during nighttime and anoxically during daytime. PMID:19424498

  9. The role of subsurface soil temperature feedbacks in summer surface air temperature variability over East Asia

    NASA Astrophysics Data System (ADS)

    Zhang, J.

    2012-12-01

    Soil temperature, an important component of land surface, can influence the climate through its effects on surface energy and water budgets and resulted changes in regional atmospheric circulation. However, the effects of soil temperature on climate variations have been less discussed. This study investigates the role of subsurface soil temperature feedbacks in influencing summer surface air temperature variability over East Asia by means of regional climate model (RCM) simulations. For this aim, two long-term simulations with and without subsurface soil temperature feedbacks are performed with the Weather Research and Forecasting (WRF) model. From our investigation, it is evident that subsurface soil temperature feedbacks make a dominant contribution to amplifying summer surface air temperature variability over the arid/semi-arid regions. Further analysis reveals that subsurface soil temperature exhibits an asymmetric effect on summer daytime and nighttime surface air temperature variability, with a stronger effect on daily minimum temperature variability than that of daily maximum temperature variability. This study provides the first RCM-based demonstration that subsurface soil temperature feedbacks play an important role in influencing climate variability over East Asia, such as summer surface air temperature. In the meanwhile, the model bias should be recognized. The results achieved by this study thus need to be further confirmed in a multi-model framework to eliminate the model dependence.

  10. Temperature Contours and Ghost Surfaces for Chaotic Magnetic Fields

    SciTech Connect

    Hudson, S. R.; Breslau, J.

    2008-03-07

    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.

  11. Offline land surface temperature assimilation in mumerical weather prediction output

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature plays an important role in land surface processes, and it is a key input to physically-based retrieval algorithms of important hydrological states and fluxes, such as soil moisture and evaporation. For this reason there are many independent estimates of land surface temperat...

  12. Temperature Contours and Ghost-Surfaces for Chaotic Magnetic Fields

    SciTech Connect

    S.R. Hudson and J. Breslau

    2008-01-31

    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. Influence of planetary-scale topography on the diurnal thermal tide during the 1971 Martian dust storm

    NASA Technical Reports Server (NTRS)

    Conrath, B. J.

    1976-01-01

    Data obtained with the Mariner 9 infrared spectroscopy experiment during the Martian Dust Storm of 1971 to 1972 are examined for evidence of topographic influence on the atmospheric thermal structure. Temperature perturbations which are well correlated with the planetary scale topography are found superposed on the large amplitude diurnal thermal tide. Applications of tidal theory to the data indicate that the observed perturbations result from the kinematic interaction of the westward traveling diurnal wave with the large scale components of topography. The dominant mode is excited by the wave-number two topography component and is a vertically evanescent eastward traveling wave with an equivalent depth comparable to the atmospheric scale height. The principle dynamic effect of this mode is the enhancement of the amplitude of the near-surface diurnal wind to over 40m/sec in limited areas near 30 deg south latitude. It appears likely that dust was injected into the atmosphere in these regions during the storm.

  14. Diurnal wind variability under heatwaves and extreme drought periods

    NASA Astrophysics Data System (ADS)

    Jiménez, Pedro A.; Vilöguerau de Arellano, Jordi; Fidel González-Rouco, J.; Navarro, Jorge; Montávez, Juan P.; García-Bustamante, Elena; Dudhia, Jimy

    2010-05-01

    Extreme weather situations produce strong impacts on society, infrastructures and ecosystems. The drought and heatwave that affected Europe in the summer of 2003 produced enormous socioeconomic implications. The anticyclonic conditions and a deficit of soil moisture availability led to the extremely high surface air temperatures registered. Several studies have shown that the characteristics of the 2003 European summer will be more frequent, more intense and longer lasting in the future. Therefore, determining atmospheric flow patterns during the heat wave and drought of 2003 is necessary in order to assess potential modifications in the circulations due to associated warmer and drier conditions. However, the effects that the extreme weather situation of the summer of 2003 produced on the surface wind have received little attention. In this work, we examine changes in the wind field due to the heatwave and drought conditions that occurred in Europe during the summer of 2003. Our analysis, based on observations and high resolution mesoscale modelling, shows a 22 % decrease in the wind diurnal cycle for summer 2003 values compared to a climatological series based on the period from 1992-2004. We discuss the wind diurnal variability in terms of the synoptic scale atmospheric conditions, and of the mesoscale and boundary layer dynamic contribution influenced by the lower values in the soil moisture. The results suggest the synoptic conditions as the main reason of the wind field change and that these are modulated by the moisture conditions of the soil.

  15. Diurnal variation of the potassium layer in the upper atmosphere

    PubMed Central

    Feng, W.; Höffner, J.; Marsh, D. R.; Chipperfield, M. P.; Dawkins, E. C. M.; Viehl, T. P.

    2015-01-01

    Abstract Measurements of the diurnal cycle of potassium (K) atoms between 80 and 110 km have been made during October (for the years 2004–2011) using a Doppler lidar at Kühlungsborn, Germany (54.1°N, 11.7°E). A pronounced diurnal variation is observed in the K number density, which is explored by using a detailed description of the neutral and ionized chemistry of K in a three‐dimensional chemistry climate model. The model captures both the amplitude and phase of the diurnal and semidiurnal variability of the layer, although the peak diurnal amplitude around 90 km is overestimated. The model shows that the total potassium density (≈ K + K+ + KHCO3) exhibits little diurnal variation at each altitude, and the diurnal variations are largely driven by photochemical conversion between these reservoir species. In contrast, tidally driven vertical transport has a small effect at this midlatitude location, and diurnal fluctuations in temperature are of little significance because they are small and the chemistry of K is relatively temperature independent. PMID:27478284

  16. Near-surface temperature lapse rates in a mountainous catchment in the Chilean Andes

    NASA Astrophysics Data System (ADS)

    Ayala; Schauwecker, S.; Pellicciotti, F.; McPhee, J. P.

    2011-12-01

    In mountainous areas, and in the Chilean Andes in particular, the irregular and sparse distribution of recording stations resolves insufficiently the variability of climatic factors such as precipitation, temperature and relative humidity. Assumptions about air temperature variability in space and time have a strong effect on the performance of hydrologic models that represent snow processes such as accumulation and ablation. These processes have large diurnal variations, and assumptions that average over longer time periods (days, weeks or months) may reduce the predictive capacity of these models under different climatic conditions from those for which they were calibrated. They also introduce large uncertainties when such models are used to predict processes with strong subdiurnal variability such as snowmelt dynamics. In many applications and modeling exercises, temperature is assumed to decrease linearly with elevation, using the free-air moist adiabatic lapse rate (MALR: 0.0065°C/m). Little evidence is provided for this assumption, however, and recent studies have shown that use of lapse rates that are uniform in space and constant in time is not appropriate. To explore the validity of this approach, near-surface (2 m) lapse rates were calculated and analyzed at different temporal resolution, based on a new data set of spatially distributed temperature sensors setup in a high elevation catchment of the dry Andes of Central Chile (approx. 33°S). Five minutes temperature data were collected between January 2011 and April 2011 in the Ojos de Agua catchment, using two Automatic Weather Stations (AWSs) and 13 T-loggers (Hobo H8 Pro Temp with external data logger), ranging in altitude from 2230 to 3590 m.s.l.. The entire catchment was snow free during our experiment. We use this unique data set to understand the main controls over temperature variability in time and space, and test whether lapse rates can be used to describe the spatial variations of air

  17. Application of radiometric surface temperature for surface energy balance estimation: John Monteith's contributions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over 25 years ago, Huband and Monteith paper’s investigating the radiative surface temperature and the surface energy balance of a wheat canopy, highlighted the key issues in computing fluxes with radiometric surface temperature. These included the relationship between radiometric and aerodynamic s...

  18. Using Microwave Observations to Estimate Land Surface Temperature during Cloudy Conditions

    NASA Astrophysics Data System (ADS)

    Holmes, T. R.; Crow, W. T.; Hain, C.; Anderson, M. C.

    2014-12-01

    Land surface temperature (LST), a key ingredient for physically-based retrieval algorithms of hydrological states and fluxes, remains a poorly constrained parameter for global scale studies. The main two observational methods to remotely measure T are based on thermal infrared (TIR) observations and passive microwave observations (MW). TIR is the most commonly used approach and the method of choice to provide standard LST products for various satellite missions. MW-based LST retrievals on the other hand are not as widely adopted for land applications; currently their principle use is in soil moisture retrieval algorithms. MW and TIR technologies present two highly complementary and independent means of measuring LST. MW observations have a high tolerance to clouds but a low spatial resolution, and TIR has a high spatial resolution with temporal sampling restricted to clear skies. The nature of the temperature at the very surface layer of the land makes it difficult to combine temperature estimates between different methods. The skin temperature is characterized by a strong diurnal cycle that is dependant in timing and amplitude on the exact sensing depth and thermal properties of the vegetation. This paper builds on recent progress in characterizing the main structural components of the DTC that explain differences in TIR and MW estimates of LST. Spatial patterns in DTC timing (phase lag with solar noon) and DTC amplitude have been calculated for TIR, MW and compared to weather prediction estimates. Based on these comparisons MW LST can be matched to the TIR record. This paper will compare in situ measurements of LST with satellite estimates from (downscaled) TIR and (reconciled) MW products. By contrasting the validation results of clear sky days with those of cloudy days the expected tolerance to clouds of the MW observations will be tested. The goal of this study is to determine the weather conditions in which MW can supplement the TIR LST record.

  19. Comparison of two methods for contactless surface temperature measurement

    NASA Astrophysics Data System (ADS)

    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.

  20. Titan Surface Temperatures as Measured by Cassini CIRS

    NASA Technical Reports Server (NTRS)

    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. Diurnal behaviour of water on Mars

    NASA Technical Reports Server (NTRS)

    Flasar, F. M.; Goody, R. M.

    1976-01-01

    A numerical model of the diurnal transport of water across the Martian surface is developed. The atmospheric boundary layer is modeled in terms of local radiative-convective processes, and radiative effects of ice fogs near the surface are included. Diffusion of water in the ground is treated for the cases of adsorption and condensation. The model is applied to the diurnal variation of water vapor in the atmosphere as observed by Barker (1974). The morning rise in the amount of water vapor can be explained in terms of the evaporation of ground fogs. The evening decrease is compatible with the model if adsorption dominates in the soil. The average level of vapor concentration requires that the atmosphere above the boundary layer be relatively dry. The ground fogs persist until midmorning and should be observable. Some consequences of these conclusions are discussed.

  2. Ground-based measurement of surface temperature and thermal emissivity

    NASA Technical Reports Server (NTRS)

    Owe, M.; Van De Griend, A. A.

    1994-01-01

    Motorized cable systems for transporting infrared thermometers have been used successfully during several international field campaigns. Systems may be configured with as many as four thermal sensors up to 9 m above the surface, and traverse a 30 m transect. Ground and canopy temperatures are important for solving the surface energy balance. The spatial variability of surface temperature is often great, so that averaged point measurements result in highly inaccurate areal estimates. The cable systems are ideal for quantifying both temporal and spatial variabilities. Thermal emissivity is also necessary for deriving the absolute physical temperature, and measurements may be made with a portable measuring box.

  3. Theoretical estimation of surface Debye temperature of nano structured material

    NASA Astrophysics Data System (ADS)

    Gangopadhyay, Bijan Kumar; Sarkar, A.

    2016-05-01

    The estimation of Debye temperature (TD) exploiting phonon is very important. In this work an attempt has been made to estimate TD for solids in a simple phenomenological approach. The ultimate goal is to estimate TD for nano structured material. The objective of this present work is to extend Debye model for nano-structured material and hence to extract the contribution to surface specific heat and surface Debye temperature. An empirical relation between TD and surface Debye temperature (TDS) is proposed. Lindemann melting criterion is also extended towards nano structure. The overall results obtained are compared and found to be in good agreement.

  4. Linking Surface Urban Heat Islands with Groundwater Temperatures.

    PubMed

    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

  5. Areal differences in diurnal variations in summer precipitation over Beijing metropolitan region

    NASA Astrophysics Data System (ADS)

    Wang, Jiali; Zhang, Renhe; Wang, Yingchun

    2012-12-01

    Using hourly rain-gauge measurements for the period 2004-2007, differences in diurnal variation in summer (June-August) precipitation are investigated in four distinct areas of Beijing: the urban area (UA), suburban area (SA), north mountainous area (NMA), and south mountainous area (SMA), which are distinguished empirically based on underlying surface conditions and verified with a statistical rotated empirical orthogonal function. The diurnal cycles and spatial patterns in seasonal mean precipitation amount, intensity, and frequency in the four areas are compared. Results show that the four areas have distinct diurnal variation patterns in precipitation amounts, with a single peak observed in UA and NMA in the late afternoon, which are 80 % and 121 % higher than their daily average, respectively, and two peaks in SA during the late afternoon and early morning with magnitudes exceeding the daily mean by 76 % and 29 %, respectively. There are also two peaks in SMA: a weaker nocturnal diurnal peak and an afternoon peak. The minimum amounts of rainfall observed in the forenoon in UA, SA, and SMA are 53 %, 47 %, and 57 % lower than the daily mean in each area, respectively, and that observed in the early morning in NMA is 50 % lower than the daily mean. The diurnal variations in precipitation intensities resemble those for precipitation amount in all four areas, but more intense precipitation is observed in SA (2.4 mm/h) than in UA (2.2 mm/h). The lowest frequency for the whole day is observed in UA, whereas the highest frequency occurs in the mountainous areas in the daytime, especially in the late afternoon in SMA. Diurnal variations in surface air temperature and divergence fields in the four areas are further investigated to interpret the physical mechanisms that underlie the spatial and temporal differences in summer diurnal precipitation, and the results indicate the possible dominance of the local circulation arising from mountain-valley wind and the

  6. Diurnal polar motion

    NASA Technical Reports Server (NTRS)

    Mcclure, P.

    1973-01-01

    An analytical theory is developed to describe diurnal polar motion in the earth which arises as a forced response due to lunisolar torques and tidal deformation. Doodson's expansion of the tide generating potential is used to represent the lunisolar torques. Both the magnitudes and the rates of change of perturbations in the earth's inertia tensor are included in the dynamical equations for the polar motion so as to account for rotational and tidal deformation. It is found that in a deformable earth with Love's number k = 0.29, the angular momentum vector departs by as much as 20 cm from the rotation axis rather than remaining within 1 or 2 cm as it would in a rigid earth. This 20 cm separation is significant in the interpretation of submeter polar motion observations because it necessitates an additional coordinate transformation in order to remove what would otherwise be a 20 cm error source in the conversion between inertial and terrestrial reference systems.

  7. Estimation of subsurface thermal structure using sea surface height and sea surface temperature

    NASA Technical Reports Server (NTRS)

    Kang, Yong Q. (Inventor); Jo, Young-Heon (Inventor); Yan, Xiao-Hai (Inventor)

    2012-01-01

    A method of determining a subsurface temperature in a body of water is disclosed. The method includes obtaining surface temperature anomaly data and surface height anomaly data of the body of water for a region of interest, and also obtaining subsurface temperature anomaly data for the region of interest at a plurality of depths. The method further includes regressing the obtained surface temperature anomaly data and surface height anomaly data for the region of interest with the obtained subsurface temperature anomaly data for the plurality of depths to generate regression coefficients, estimating a subsurface temperature at one or more other depths for the region of interest based on the generated regression coefficients and outputting the estimated subsurface temperature at the one or more other depths. Using the estimated subsurface temperature, signal propagation times and trajectories of marine life in the body of water are determined.

  8. Diurnal warming in shallow coastal seas: Observations from the Caribbean and Great Barrier Reef regions

    NASA Astrophysics Data System (ADS)

    Zhu, X.; Minnett, P. J.; Berkelmans, R.; Hendee, J.; Manfrino, C.

    2014-07-01

    A good understanding of diurnal warming in the upper ocean is important for the validation of satellite-derived sea surface temperature (SST) against in-situ buoy data and for merging satellite SSTs taken at different times of the same day. For shallow coastal regions, better understanding of diurnal heating could also help improve monitoring and prediction of ecosystem health, such as coral reef bleaching. Compared to its open ocean counterpart which has been studied extensively and modeled with good success, coastal diurnal warming has complicating localized characteristics, including coastline geometry, bathymetry, water types, tidal and wave mixing. Our goal is to characterize coastal diurnal warming using two extensive in-situ temperature and weather datasets from the Caribbean and Great Barrier Reef (GBR), Australia. Results showed clear daily warming patterns in most stations from both datasets. For the three Caribbean stations where solar radiation is the main cause of daily warming, the mean diurnal warming amplitudes were about 0.4 K at depths of 4-7 m and 0.6-0.7 K at shallower depths of 1-2 m; the largest warming value was 2.1 K. For coral top temperatures of the GBR, 20% of days had warming amplitudes >1 K, with the largest >4 K. The bottom warming at shallower sites has higher daily maximum temperatures and lower daily minimum temperatures than deeper sites nearby. The averaged daily warming amplitudes were shown to be closely related to daily average wind speed and maximum insolation, as found in the open ocean. Diurnal heating also depends on local features including water depth, location on different sections of the reef (reef flat vs. reef slope), the relative distance from the barrier reef chain (coast vs. lagoon stations vs. inner barrier reef sites vs. outer rim sites); and the proximity to the tidal inlets. In addition, the influence of tides on daily temperature changes and its relative importance compared to solar radiation was quantified by

  9. Diurnal Reflectance Changes in Vegetation Observed with AVIRIS

    NASA Technical Reports Server (NTRS)

    Vanderbilt, V. C.; Ambrosia, V. G.; Ustin, S. L.

    1998-01-01

    Among the most important short-term dynamic biological processes are diurnal changes in canopy water relations. Plant regulation of water transport through stomatal openings affects other gaseous transport processes, often dramatically decreasing photosynthetic fixation of carbon dioxide during periods of water stress. Water stress reduces stomatal conductance of water vapor through the leaf surface and alters the diurnal timing of stomatal opening. Under non-water stressed conditions, stomates typically open soon after dawn and transpire water vapor throughout the daylight period. During stress periods, stomates may close for part of the day, generally near mid-day. Under prolonged stress conditions, stomatal closure shifts to earlier times during the day; stomates may close by mid-morning and remain closed until the following morning - or remain closed entirely. Under these conditions the relationship between canopy greenness (e.g., measured with a vegetation index or by spectral mixture analysis) and photosynthetic fixation of carbon is lost and the remotely sensed vegetation metric is a poor predictor of gas exchange. Prediction of stomatal regulation and exchange of water and trace gases is critical for ecosystem and climate models to correctly estimate budgets of these gases and understand or predict other processes like gross and net ecosystem primary production. Plant gas exchange has been extensively studied by physiologists at the leaf and whole plant level and by biometeorologists at somewhat larger scales. While these energy driven processes follow a predictable if somewhat asymmetric diurnal cycle dependent on soil water availability and the constraints imposed by the solar energy budget, they are nonetheless difficult to measure at the tree and stand levels using conventional methods. Ecologists have long been interested in the potential of remote sensing for monitoring physiological changes using multi-temporal images. Much of this research has

  10. Surface Temperatures on Titan; Changes During the Cassini Mission

    NASA Technical Reports Server (NTRS)

    Jennings, Donald E.; Cottini, Valeria; Nixon, Conor A.

    2010-01-01

    Surface brightness temperatures on Titan measured by the Composite Infrared Spectrometer (CIRS) aboard Cassini span the period from late northern winter to early spring. The CIRS observations cover all latitudes and can be used to study meridional changes with season. CIRS previously reported surface temperatures from 2004-2008 which were 93.7 K at the equator with decreases of 2 K toward the south pole and 3 K toward the north pole'. From a comparison of the equinox period with the earlier data, CIRS can now detect a seasonal shift in the latitudinal distribution of temperatures. Around the time of the equinox the meridional distribution was more symmetric about the equator than had been found earlier in the mission. The equatorial surface temperatures remained close to 94 K, but in the south the temperatures had decreased by about 0.5 K and in the north had increased by about 0.5 K. The CIRS equinox results are similar to what was seen near the previous vernal equinox by Voyager IRIS Z. The observed surface temperatures can help constrain the type of surface material by comparison with predictions from general circulation models. Of the three cases treated by Tokano t , our measurements most closely match a porous-ice regolith. As Cassini continues through Titan's northern spring CIRS will extend its temporal and spatial coverage and will continue to search for seasonal variations in surface temperature.

  11. Land surface skin temperatures from a combined analysis of microwave and infrared satellite observations for an all-weather evaluation of the differences between air and skin temperatures

    NASA Astrophysics Data System (ADS)

    Prigent, Catherine; Aires, Filipe; Rossow, William B.

    2003-05-01

    A neural network inversion scheme including first guess information has been developed to retrieve surface temperature Ts, along with atmospheric water vapor, cloud liquid water, and surface emissivities over land from a combined analysis of Special Sensor Microwave/Imager (SSM/I) and International Satellite Cloud Climatology Project (ISCCP) data. In the absence of routine in situ surface skin measurements, retrieved Ts values are evaluated by comparison to the surface air temperature Tair measured by the meteorological station network. The Ts - Tair difference shows all the expected variations with solar flux, soil characteristics, and cloudiness. During daytime the Ts - Tair difference is driven by the solar insulation, with positive differences that increase with increasing solar flux. With decreasing soil and vegetation moisture the evaporation rate decreases, increasing the sensible heat flux, thus requiring larger Ts - Tair differences. Nighttime Ts - Tair differences are governed by the longwave radiation balance, with Ts usually closer or lower than Tair. The presence of clouds dampens all the difference. After suppression of the variability associated to the diurnal solar flux variations, the Ts and Tair data sets show very good agreement in their synoptic variations, even for cloudy cases, with no bias and a global rms difference of ˜2.9 K. This value is an upper limit of the retrieval rms because it includes errors in the in situ data as well as errors related to imperfect time and space collocations between the satellite and in situ measurements.

  12. A physically based model of global freshwater surface temperature

    NASA Astrophysics Data System (ADS)

    van Beek, Ludovicus P. H.; Eikelboom, Tessa; van Vliet, Michelle T. H.; Bierkens, Marc F. P.

    2012-09-01

    Temperature determines a range of physical properties of water and exerts a strong control on surface water biogeochemistry. Thus, in freshwater ecosystems the thermal regime directly affects the geographical distribution of aquatic species through their growth and metabolism and indirectly through their tolerance to parasites and diseases. Models used to predict surface water temperature range between physically based deterministic models and statistical approaches. Here we present the initial results of a physically based deterministic model of global freshwater surface temperature. The model adds a surface water energy balance to river discharge modeled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff, and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by shortwave and longwave radiation and sensible and latent heat fluxes. Also included are ice formation and its effect on heat storage and river hydraulics. We use the coupled surface water and energy balance model to simulate global freshwater surface temperature at daily time steps with a spatial resolution of 0.5° on a regular grid for the period 1976-2000. We opt to parameterize the model with globally available data and apply it without calibration in order to preserve its physical basis with the outlook of evaluating the effects of atmospheric warming on freshwater surface temperature. We validate our simulation results with daily temperature data from rivers and lakes (U.S. Geological Survey (USGS), limited to the USA) and compare mean monthly temperatures with those recorded in the Global Environment Monitoring System (GEMS) data set. Results show that the model is able to capture the mean monthly surface temperature for the majority of the GEMS stations, while the interannual variability as derived from the USGS and NOAA data was captured reasonably well. Results are poorest for

  13. Insolation and Resulting Surface Temperatures of the Kuiper-Rudaki Study Region on Mercury.

    NASA Astrophysics Data System (ADS)

    Bauch, Karin E.; Hiesinger, Harald; D'Amore, Mario; Helbert, Jörn; Weinauer, Julia

    2016-04-01

    The imaging spectrometer MERTIS (Mercury Radiometer and Thermal Infrared Spectrometer) is part of the payload of ESA's BepiColombo mission, which is scheduled for launch in 2017 [1]. The instrument consists of an IR-spectrometer and radiometer, which observe the surface in the wavelength range of 7-14 and 7-40μm, respectively. The four scientific objectives are to a) study Mercury's surface composition, b) identify rock-forming minerals, c) globally map the surface mineralogy and d) study surface temperature and thermal inertia [1, 2]. In preparation of the MERTIS experiment, we performed detailed thermal models of the lunar surface, which we extrapolated to Mercury. In order to calculate insolation and surface temperatures, we use a numerical model, which has been described by [7]. Surface temperatures are dependent on the surface and subsurface bulk thermophysical properties, such as bulk density, heat capacity, thermal conductivity, emissivity, topography, and albedo. Lunar and Mercurian surface temperatures show the same general characteristics. Both have very steep temperature gradients at sunrise and sunset, due to the lack of an atmosphere. However, there are major differences due to the orbital characteristics. On Mercury the 3:2 resonant rotation rate and the eccentric orbit causes local noon at longitudes 0° and 180° to coincide with perihelion, which leads to "hot poles". At longitudes 90° and 270° , local noon coincides with aphelion, which results in "cold poles" [8]. At these longitudes brief secondary sunrises and sunsets are visible, when Mercury's orbital angular velocity exceeds the spin rate during perihelion [8]. Here we present diurnal temperature curves of the Kuiper-Rudaki study region, based on thermophysical estimates and MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging [9]) albedo data with a resolution of 1000m/px. Our study region spans more than 90° along the equator, thus allowing us to study both, hot and

  14. Surface temperatures and glassy state investigations in tribology, part 1

    NASA Technical Reports Server (NTRS)

    Winer, W. O.; Sanborn, D. M.

    1978-01-01

    The research in this report is divided into two categories: (1) lubricant rheological behavior, and (2) thermal behavior of a simulated elastohydrodynamic contact. The studies of the lubricant rheological behavior consists of high pressure, low shear rate viscosity measurements, viscoelastic transition measurements, by volume dilatometry, dielectric transitions at atmospheric pressure and light scattering transitions. Lubricant shear stress-strain behavior in the amorphous glassy state was measured on several fluids. It appears clear from these investigations that many lubricants undergo viscoplastic transitions in typical EHD contacts and that the lubricant has a limiting maximum shear stress it can support which in turn will determine the traction in the contact except in cases of very low slide-roll ratio. Surface temperature measurements were made for a naphthenic mineral oil and a polyphenyl ether. The maximum surface temperature in these experiments was approximately symmetrical about the zero slide-roll ration except for absolute values of slide-roll ratio greater than about 0.9. Additional surface temperature measurements were made in contacts with rough surfaces where the composite surface roughness was approximately equal to the EHD film thickness. A regression analysis was done to obtain a predictive equation for surface temperatures as a function of pressure, sliding speed, and surface roughness. A correction factor for surface roughness effects to the typical flash temperature analysis was found.

  15. Surface Tension Gradients Induced by Temperature: The Thermal Marangoni Effect

    ERIC Educational Resources Information Center

    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.

  16. High temperature photoelectron emission and surface photovoltage in semiconducting diamond

    SciTech Connect

    Williams, G. T.; Cooil, S. P.; Roberts, O. R.; Evans, S.; Langstaff, D. P.; Evans, D. A.

    2014-08-11

    A non-equilibrium photovoltage is generated in semiconducting diamond at above-ambient temperatures during x-ray and UV illumination that is sensitive to surface conductivity. The H-termination of a moderately doped p-type diamond (111) surface sustains a surface photovoltage up to 700 K, while the clean (2 × 1) reconstructed surface is not as severely affected. The flat-band C 1s binding energy is determined from 300 K measurement to be 283.87 eV. The true value for the H-terminated surface, determined from high temperature measurement, is (285.2 ± 0.1) eV, corresponding to a valence band maximum lying 1.6 eV below the Fermi level. This is similar to that of the reconstructed (2 × 1) surface, although this surface shows a wider spread of binding energy between 285.2 and 285.4 eV. Photovoltage quantification and correction are enabled by real-time photoelectron spectroscopy applied during annealing cycles between 300 K and 1200 K. A model is presented that accounts for the measured surface photovoltage in terms of a temperature-dependent resistance. A large, high-temperature photovoltage that is sensitive to surface conductivity and photon flux suggests a new way to use moderately B-doped diamond in voltage-based sensing devices.

  17. Heterogeneity in diurnal variation of tropospheric convection over Indian region

    NASA Astrophysics Data System (ADS)

    Muhammed, Muhsin; Sunilkumar, S. V.

    2016-07-01

    The tropical Tropopause and the features of the Tropical Tropopause Layer (TTL) are governed by troposheric convection from below and radiative heating from above (stratosphere). The brightness temperature in the thermal infrared channel (IRBT) is used as a proxy for identifying tropospheric convection and deep convective clouds. IRBT from Very High Resolution Radiometer (VHRR) onboard KALPANA-1 during different seasons of 2008 to 2014 is being used to examine the heterogeneity of tropospheric convection. Over Indian peninsula, 36 regions have been identified with a spatial resolution of ±0.7° (81 pixels) with equal distance in both longitude and latitude. During monsoon season, a clear diurnal variation in convection is noticed over land when compared with over ocean. Over inland regions, the occurrence of deeper convection occurs during evening and early morning with different diurnal patterns. This can be due to the inhomogeneity of the terrain. It can be noted that the diurnal convection pattern over Arabian Sea is different than Bay of Bengal diurnal convection pattern. Regions near to the western-ghat do not show a clear diurnal variation and shows high occurrence of midlevel clouds (IRBT<265K). During winter (DJF), the occurrence of IRBT below 280K is very less at any time of the day over both land and ocean, which indicates the occurrence of deeper convection is rare. Hence, during winter, the diurnal variations of convection over both land and ocean has insignificant diurnal pattern.

  18. Sea Surface Temperature from EUMETSAT Including Sentinel-3 SLSTR

    NASA Astrophysics Data System (ADS)

    O'Carroll, Anne; Bonekamp, Hans; Montagner, Francois; Santacesaria, Vincenzo; Tomazic, Igor

    2015-12-01

    The paper gives an overview of sea surface temperature (SST) activities at EUMETSAT including information on SST planned from the Sea and Land Surface Temperature Radiometer (SLSTR). Operational oceanography activities within the Marine Applications group at EUMETSAT continue with a focus on SST, sea surface winds, sea-ice products, radiative fluxes, significant wave height and sea surface topography. These are achieved through the mandatory, optional and third-party programmes, and for some products with the EUMETSAT Ocean and Sea-Ice Satellite Application Facility (OSI SAF). Progress towards products from sea-ice surface temperature, ocean colour products, turbidity and aerosol optical depth over water continue. Information on oceanography products from EUMETSAT can be found through the product navigator (http://navigator.eumetsat.int). EUMETSAT have been collaborating with ESA for a number of years on the development of SST for SLSTR.

  19. Surface temperature transients from pulsed laser heating of UO 2

    NASA Astrophysics Data System (ADS)

    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. Coordinated in situ and orbital observations of ground temperature by the Mars Science Laboratory Ground Temperature Sensor and Mars Odyssey Thermal Emission Imaging System: Implications for thermal modeling of the Martian surface

    NASA Astrophysics Data System (ADS)

    Hamilton, V. E.; Vasavada, A. R.; Christensen, P. R.; Mischna, M. A.; Team, M.

    2013-12-01

    Diurnal variations in Martian ground surface temperature probe the physical nature (mean particle size, lateral/vertical heterogeneity, cementation, etc.) of the upper few centimeters of the subsurface. Thermal modeling of measured temperatures enables us to make inferences about these physical properties, which in turn offer valuable insight into processes that have occurred over geologic timescales. Add the ability to monitor these temperature/physical variations over large distances and it becomes possible to infer a great deal about local- to regional scale geologic processes and characteristics that are valuable to scientific and engineering studies. The Thermal Emission Imaging System (THEMIS) instrument measures surface temperatures from orbit at a restricted range of local times (~3:00 - 6:00 am/pm). The Rover Environmental Monitoring Station Ground Temperature Sensor (REMS GTS) on the Mars Science Laboratory (MSL) acquires hourly temperature measurements in the vicinity of the rover. With the additional information that MSL's full diurnal coverage offers, we are interested in correlating the thermophysical properties inferred from these local-scale measurements with those obtained from MSL's visible images and orbital THEMIS measurements at only a few times of day. To optimize the comparisons, we have been acquiring additional REMS observations simultaneously with Mars Odyssey overflights during which THEMIS is able to observe MSL's location. We also characterize surface particle size distributions within the field of view of the GTS. We will present comparisons of the temperatures derived from GTS and THEMIS, focusing on eight simultaneous observations of ground temperature acquired between sols 100 and 360. These coordinated observations allow us to cross-check temperatures derived in situ and from orbit, and compare rover-scale observations of thermophysical and particle size properties to those made at remote sensing scales.

  1. Evaluation of a surface/vegetation parameterization using satellite measurements of surface temperature

    NASA Technical Reports Server (NTRS)

    Taconet, O.; Carlson, T.; Bernard, R.; Vidal-Madjar, D.

    1986-01-01

    Ground measurements of surface-sensible heat flux and soil moisture for a wheat-growing area of Beauce in France were compared with the values derived by inverting two boundary layer models with a surface/vegetation formulation using surface temperature measurements made from NOAA-AVHRR. The results indicated that the trends in the surface heat fluxes and soil moisture observed during the 5 days of the field experiment were effectively captured by the inversion method using the remotely measured radiative temperatures and either of the two boundary layer methods, both of which contain nearly identical vegetation parameterizations described by Taconet et al. (1986). The sensitivity of the results to errors in the initial sounding values or measured surface temperature was tested by varying the initial sounding temperature, dewpoint, and wind speed and the measured surface temperature by amounts corresponding to typical measurement error. In general, the vegetation component was more sensitive to error than the bare soil model.

  2. Surface Temperatures on Titan during Northern Winter and Spring

    NASA Astrophysics Data System (ADS)

    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. Surface Temperatures on Titan During Northern Winter and Spring

    NASA Technical Reports Server (NTRS)

    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 plus or minus 0.3 to 89.7 plus or minus 0.5 K while at the north pole the temperature increased by 1 K from 90.7 plus or minus 0.5 to 91.5 plus or minus 0.2 K. The latitude of maximum temperature moved from 19 S to 16 N, tracking the subsolar latitude. As the latitude changed, the maximum temperature remained constant at 93.65 plus or minus 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.

  4. Global Surface Temperature Change and Uncertainties Since 1861

    NASA Technical Reports Server (NTRS)

    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. SPATIAL VARIABILITY OF REMOTELY SENSED SURFACE TEMPERATURE AT FIELD SCALE

    EPA Science Inventory

    Bare soil surface temperatures (BST) and crop canopy temperatures (CCT) were collected from a 1-ha field in central Arizona using an infrared thermometer to determine whether they were spatially correlated. The measurements were taken from a two-dimensional random sampling patter...

  6. Surface Gravity and Hawking Temperature from Entropic Force Viewpoint

    NASA Astrophysics Data System (ADS)

    Aaltonen, T.; Adelman, J.; Álvarez González, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.; Apresyan, A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Attal, A.; Aurisano, A.; Azfar, F.; Badgett, W.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauer, G.; Beauchemin, P.-H.; Bedeschi, F.; Beecher, D.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Binkley, M.; Bisello, D.; Bizjak, I.; Blair, R. E.; Blocker, C.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Boisvert, V.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brau, B.; Bridgeman, A.; Brigliadori, L.; Bromberg, C.; Brubaker, E.; Budagov, J.; Budd, H. S.; Budd, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Byrum, K. L.; Cabrera, S.; Calancha, C.; Camarda, S.; Campanelli, M.; Campbell, M.; Canelli, F.; Canepa, A.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chang, S. H.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chou, J. P.; Chung, K.; Chung, W. H.; Chung, Y. S.; Chwalek, T.; Ciobanu, C. I.; Ciocci, M. A.; Clark, A.; Clark, D.; Compostella, G.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Crescioli, F.; Cuenca Almenar, C.; Cuevas, J.; Culbertson, R.; Cully, J. C.; Dagenhart, D.; D'Ascenzo, N.; Datta, M.; Davies, T.; de Barbaro, P.; de Cecco, S.; Deisher, A.; de Lorenzo, G.; Dell'Orso, M.; Deluca, C.; Demortier, L.; Deng, J.; Deninno, M.; D'Errico, M.; di Canto, A.; di Ruzza, B.; Dittmann, J. R.; D'Onofrio, M.; Donati, S.; Dong, P.; Dorigo, T.; Dube, S.; Ebina, K.; Elagin, A.; Erbacher, R.; Errede, D.; Errede, S.; Ershaidat, N.; Eusebi, R.; Fang, H. C.; Farrington, S.; Fedorko, W. T.; Feild, R. G.; Feindt, M.; Fernandez, J. P.; Ferrazza, C.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M. J.; Franklin, M.; Freeman, J. C.; Furic, I.; Gallinaro, M.; Galyardt, J.; Garberson, F.; Garcia, J. E.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerdes, D.; Gessler, A.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Gimmell, J. L.; Ginsburg, C. M.; Giokaris, N.; Giordani, M.; Giromini, P.; Giunta, M.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gresele, A.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Grundler, U.; Guimaraes da Costa, J.; Gunay-Unalan, Z.; Haber, C.; Hahn, S. R.; Halkiadakis, E.; Han, B.-Y.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harr, R. F.; Hartz, M.; Hatakeyama, K.; Hays, C.; Heck, M.; Heinrich, J.; Herndon, M.; Heuser, J.; Hewamanage, S.; Hidas, D.; Hill, C. S.; Hirschbuehl, D.; Hocker, A.; Hou, S.; Houlden, M.; Hsu, S.-C.; Hughes, R. E.; Hurwitz, M.; Husemann, U.; Hussein, M.; Huston, J.; Incandela, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jha, M. K.; Jindariani, S.; Johnson, W.; Jones, M.; Joo, K. K.; Jun, S. Y.; Jung, J. E.; Junk, T. R.; Kamon, T.; Kar, D.; Karchin, P. E.; Kato, Y.; Kephart, R.; Ketchum, W.; Keung, J.; Kietzman, B.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, H. W.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kimura, N.; Kirsch, L.; Klimenko, S.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Korytov, A.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Krop, D.; Krumnack, N.; Kruse, M.; Krutelyov, V.; Kuhr, T.; Kulkarni, N. P.; Kurata, M.; Kwang, S.; Laasanen, A. T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; Lazzizzera, I.; Lecompte, T.; Lee, E.; Lee, H. S.; Lee, J. S.; Lee, S. W.; Leone, S.; Lewis, J. D.; Lin, C.-J.; Linacre, J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, C.; Liu, T.; Lockyer, N. S.; Loginov, A.; Lovas, L.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; MacQueen, D.; Madrak, R.; Maeshima, K.; Makhoul, K.; Maksimovic, P.; Malde, S.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Marino, C. P.; Martin, A.; Martin, V.; Martínez, M.; Martínez-Ballarín, R.; Mastrandrea, P.; Mathis, M.; Mattson, M. E.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Menzione, A.; Mesropian, C.; Miao, T.; Mietlicki, D.; Miladinovic, N.; Miller, R.; Mills, C.; Milnik, M.; Mitra, A.; Mitselmakher, G.; Miyake, H.; Moed, S.; Moggi, N.; Mondragon, M. N.; Moon, C. S.; Moore, R.; Morello, M. J.; Morlock, J.; Movilla Fernandez, P.; Mülmenstädt, J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.

    We consider a freely falling holographic screen for the Schwarzschild and Reissner-Nordström black holes and evaluate the entropic force à la Verlinde. When the screen crosses the event horizon, the temperature of the screen agrees to the Hawking temperature and the entropic force gives rise to the surface gravity for both of the black holes.

  7. Hydromagnetic Steady Flow of Maxwell Fluid over a Bidirectional Stretching Surface with Prescribed Surface Temperature and Prescribed Surface Heat Flux

    PubMed Central

    Shehzad, Sabir Ali; Alsaedi, Ahmad; Hayat, Tasawar

    2013-01-01

    This paper investigates the steady hydromagnetic three-dimensional boundary layer flow of Maxwell fluid over a bidirectional stretching surface. Both cases of prescribed surface temperature (PST) and prescribed surface heat flux (PHF) are considered. Computations are made for the velocities and temperatures. Results are plotted and analyzed for PST and PHF cases. Convergence analysis is presented for the velocities and temperatures. Comparison of PST and PHF cases is given and examined. PMID:23874523

  8. Correlation of noninvasive surface temperature measurement with rectal temperature in swine.

    PubMed

    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

  9. Radar Backscatter Across the Gulf Stream Sea Surface Temperature Front

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Li, F. K.; Walsh, E. J.; Lou, S. H.

    1998-01-01

    Ocean backscatter signatures were measured by the Jet Propulsion Laboratory airborne NUSCAT K(sub u)-band scatterometer across the Gulf Stream sea surface temperature front. The measurements were made during the Surface Wave Dynamics Experiment (SWADE) off the coast of Virginia and Maryland in the winter of 1991.

  10. Effects and Mitigation of Clear Sky Sampling on Recorded Trends in Land Surface Temperature

    NASA Astrophysics Data System (ADS)

    Holmes, T. R.; Hain, C.; de Jeu, R.; Anderson, M. C.; Crow, W. T.

    2015-12-01

    Land surface temperature (LST) is a key input for physically-based retrieval algorithms of hydrological states and fluxes. Yet, it remains a poorly constrained parameter for global scale studies. The main two observational methods to remotely measure T are based on thermal infrared (TIR) observations and passive microwave observations (MW). TIR is the most commonly used approach and the method of choice to provide standard LST products for various satellite missions. MW-based LST retrievals on the other hand are not as widely adopted for land applications; currently their principle use is in soil moisture retrieval algorithms. MW and TIR technologies present two highly complementary and independent means of measuring LST. MW observations have a high tolerance to clouds but a low spatial resolution, and TIR has a high spatial resolution with temporal sampling restricted to clear skies. This paper builds on recent progress in characterizing the main structural differences between TIR LST and MW Ka-band observations, the MW frequency that is most suitable for LST sensing. By accounting for differences in diurnal timing (phase lag with solar noon), amplitude, and emissivity we construct a MW-based LST dataset that matches the diurnal characteristics of the TIR-based LSA SAF LST record. This new global dataset of MW-based LST currently spans the period of 2003-2013. In this paper we will present results of a validation of MW LST with in situ data with special emphasis on the effect of cloudiness on the performance. The ability to remotely sense the temperature of cloud covered land is what sets this MW-LST datasets apart from existing (much higher resolution) TIR-based products. As an example of this we will therefore explore how MW LST can mitigate the effect of clear-sky sampling in the context of trend and anomaly detection. We do this by contrasting monthly means of TIR-LST with its clear-sky and all-sky equivalent from an MW-LST and an NWP model.

  11. Measurement of transient surface temperatures during rubbing using infrared thermography

    NASA Astrophysics Data System (ADS)

    You, Tau; Yu, Jianwei; Yu, Xiaofen

    2013-10-01

    Infrared thermometer could provide IR radiance information to get the corresponding temperature as the machine is working. But the emissivity coefficient, which converts IR radiance to temperature, would vary with change of surface properties during rubbing, and this would bring dynamic error in measurement. In this study, we introduced a special tester, in the side of which compact IR thermometer are mounted. The thermometer enables us to measure contact surface temperature directly during tests of a rotating ring and a flat block which had a laser diode fixed under its contact surface. Based on Kirchhoff theory, the calculate model of the spectral emissivity is constructed. The normal emissivity at target region are measured through trigonometric ray consisted of InGaAsP laser source, PbSe detector and objective surface. So the temperature value from the IR thermometer could be corrected dynamically according to the real-time emissivity. The structure and the principle of the apparatus are described. The key technologies and the corresponding solution methods are briefly discussed. The error due to the rapid variations of emissivity value with change in contact conditions was shown, and it must be taken into consideration in radiometric temperature measurement in rubbing and could be especially useful in the verification of friction surface temperature predictions.

  12. Measuring the Surface Temperature of the Cryosphere using Remote Sensing

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.

    2012-01-01

    A general description of the remote sensing of cryosphere surface temperatures from satellites will be provided. This will give historical information on surface-temperature measurements from space. There will also be a detailed description of measuring the surface temperature of the Greenland Ice Sheet using Moderate-Resolution Imaging Spectroradiometer (MODIS) data which will be the focus of the presentation. Enhanced melting of the Greenland Ice Sheet has been documented in recent literature along with surface-temperature increases measured using infrared satellite data since 1981. Using a recently-developed climate data record, trends in the clear-sky ice-surface temperature (IST) of the Greenland Ice Sheet have been studied using the MODIS IST product. Daily and monthly MODIS ISTs of the Greenland Ice Sheet beginning on 1 March 2000 and continuing through 31 December 2010 are now freely available to download at 6.25-km spatial resolution on a polar stereographic grid. Maps showing the maximum extent of melt for the entire ice sheet and for the six major drainage basins have been developed from the MODIS IST dataset. Twelve-year trends of the duration of the melt season on the ice sheet vary in different drainage basins with some basins melting progressively earlier over the course of the study period. Some (but not all) of the basins also show a progressively-longer duration of melt. The consistency of this IST record, with temperature and melt records from other sources will be discussed.

  13. Surface plasmon enhanced photoluminescence from copper nanoparticles: Influence of temperature

    SciTech Connect

    Yeshchenko, Oleg A. Bondarchuk, Illya S.; Losytskyy, Mykhaylo Yu.

    2014-08-07

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Mathematical model of the metal mould surface temperature optimization

    SciTech Connect

    Mlynek, Jaroslav Knobloch, Roman; Srb, Radek

    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 optimization process. For temperate calculations software system ANSYS was used. A practical example of optimization of heaters locations and calculation of the temperature of the mould is included at the end of the article.

  16. Mathematical model of the metal mould surface temperature optimization

    NASA Astrophysics Data System (ADS)

    Mlynek, Jaroslav; Knobloch, Roman; Srb, Radek

    2015-11-01

    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 optimization process. For temperate calculations software system ANSYS was used. A practical example of optimization of heaters locations and calculation of the temperature of the mould is included at the end of the article.

  17. On estimating total daily evapotranspiration from remote surface temperature measurements

    NASA Technical Reports Server (NTRS)

    Carlson, Toby N.; Buffum, Martha J.

    1989-01-01

    A method for calculating daily evapotranspiration from the daily surface energy budget using remotely sensed surface temperature and several meteorological variables is presented. Vaules of the coefficients are determined from simulations with a one-dimensional boundary layer model with vegetation cover. Model constants are obtained for vegetation and bare soil at two air temperature and wind speed levels over a range of surface roughness and wind speeds. A different means of estimating the daily evapotranspiration based on the time rate of increase of surface temperature during the morning is also considered. Both the equations using our model-derived constants and field measurements are evaluated, and a discussion of sources of error in the use of the formulation is given.

  18. Symmetric scaling properties in global surface air temperature anomalies

    NASA Astrophysics Data System (ADS)

    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.

  19. Land Surface Temperature Measurements form EOS MODIS Data

    NASA Technical Reports Server (NTRS)

    Wan, Zhengming

    1996-01-01

    We have developed a physics-based land-surface temperature (LST) algorithm for simultaneously retrieving surface band-averaged emissivities and temperatures from day/night pairs of MODIS (Moderate Resolution Imaging Spectroradiometer) data in seven thermal infrared bands. The set of 14 nonlinear equations in the algorithm is solved with the statistical regression method and the least-squares fit method. This new LST algorithm was tested with simulated MODIS data for 80 sets of band-averaged emissivities calculated from published spectral data of terrestrial materials in wide ranges of atmospheric and surface temperature conditions. Comprehensive sensitivity and error analysis has been made to evaluate the performance of the new LST algorithm and its dependence on variations in surface emissivity and temperature, upon atmospheric conditions, as well as the noise-equivalent temperature difference (NE(Delta)T) and calibration accuracy specifications of the MODIS instrument. In cases with a systematic calibration error of 0.5%, the standard deviations of errors in retrieved surface daytime and nighttime temperatures fall between 0.4-0.5 K over a wide range of surface temperatures for mid-latitude summer conditions. The standard deviations of errors in retrieved emissivities in bands 31 and 32 (in the 10-12.5 micrometer IR spectral window region) are 0.009, and the maximum error in retrieved LST values falls between 2-3 K. Several issues related to the day/night LST algorithm (uncertainties in the day/night registration and in surface emissivity changes caused by dew occurrence, and the cloud cover) have been investigated. The LST algorithms have been validated with MODIS Airborne Simulator (MAS) dada and ground-based measurement data in two field campaigns conducted in Railroad Valley playa, NV in 1995 and 1996. The MODIS LST version 1 software has been delivered.

  20. HCMM/soil moisture experiment. [relationship between surface minus air temperature differential and available water according to crop type in Canada

    NASA Technical Reports Server (NTRS)

    Cihlar, J. (Principal Investigator)

    1980-01-01

    Progress in the compilation and analysis of airborne and ground data to determine the relationship between the maximum surface minus maximum air temperature differential (delta Tsa) and available water (PAW) is reported. Also, results of an analysis of HCMM images to determine the effect of cloud cover on the availability of HCMM-type data are presented. An inverse relationship between delta Tsa and PAW is indicated along with stable delta Tsa vs. PAW distributions for fully developed canopies. Large variations, both geographical and diurnal, in the cloud cover images are reported. The average monthly daytime cloud cover fluctuated between 40 and 60 percent.

  1. Interannual variation of the surface temperature of tropical forests from satellite observations

    DOE PAGESBeta

    Gao, Huilin; Zhang, Shuai; Fu, Rong; Li, Wenhong; Dickinson, Robert E.

    2016-01-01

    Land surface temperatures (LSTs) within tropical forests contribute to climate variations. However, observational data are very limited in such regions. This study used passive microwave remote sensing data from the Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS), providing observations under all weather conditions, to investigate the LST over the Amazon and Congo rainforests. The SSM/I and SSMIS data were collected from 1996 to 2012. The morning and afternoon observations from passive microwave remote sensing facilitate the investigation of the interannual changes of LST anomalies on a diurnal basis. As a result of the variability ofmore » cloud cover and the corresponding reduction of solar radiation, the afternoon LST anomalies tend to vary more than the morning LST anomalies. The dominant spatial and temporal patterns for interseasonal variations of the LST anomalies over the tropical rainforest were analyzed. The impacts of droughts and El Niños on this LST were also investigated. Lastly, the differences between early morning and late afternoon LST anomalies were identified by the remote sensing product, with the morning LST anomalies controlled by humidity (according to comparisons with the National Centers for Environmental Prediction (NCEP) reanalysis data).« less

  2. Interannual variation of the surface temperature of tropical forests from satellite observations

    SciTech Connect

    Gao, Huilin; Zhang, Shuai; Fu, Rong; Li, Wenhong; Dickinson, Robert E.

    2016-01-01

    Land surface temperatures (LSTs) within tropical forests contribute to climate variations. However, observational data are very limited in such regions. This study used passive microwave remote sensing data from the Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS), providing observations under all weather conditions, to investigate the LST over the Amazon and Congo rainforests. The SSM/I and SSMIS data were collected from 1996 to 2012. The morning and afternoon observations from passive microwave remote sensing facilitate the investigation of the interannual changes of LST anomalies on a diurnal basis. As a result of the variability of cloud cover and the corresponding reduction of solar radiation, the afternoon LST anomalies tend to vary more than the morning LST anomalies. The dominant spatial and temporal patterns for interseasonal variations of the LST anomalies over the tropical rainforest were analyzed. The impacts of droughts and El Niños on this LST were also investigated. Lastly, the differences between early morning and late afternoon LST anomalies were identified by the remote sensing product, with the morning LST anomalies controlled by humidity (according to comparisons with the National Centers for Environmental Prediction (NCEP) reanalysis data).

  3. Derivation and evaluation of land surface temperature from the geostationary operational environmental satellite series

    NASA Astrophysics Data System (ADS)

    Fang, Li

    The Geostationary Operational Environmental Satellites (GOES) have been continuously monitoring the earth surface since 1970, providing valuable and intensive data from a very broad range of wavelengths, day and night. The National Oceanic and Atmospheric Administration's (NOAA's) National Environmental Satellite, Data, and Information Service (NESDIS) is currently operating GOES-15 and GOES-13. The design of the GOES series is now heading to the 4 th generation. GOES-R, as a representative of the new generation of the GOES series, is scheduled to be launched in 2015 with higher spatial and temporal resolution images and full-time soundings. These frequent observations provided by GOES Image make them attractive for deriving information on the diurnal land surface temperature (LST) cycle and diurnal temperature range (DTR). These parameters are of great value for research on the Earth's diurnal variability and climate change. Accurate derivation of satellite-based LSTs from thermal infrared data has long been an interesting and challenging research area. To better support the research on climate change, the generation of consistent GOES LST products for both GOES-East and GOES-West from operational dataset as well as historical archive is in great demand. The derivation of GOES LST products and the evaluation of proposed retrieval methods are two major objectives of this study. Literature relevant to satellite-based LST retrieval techniques was reviewed. Specifically, the evolution of two LST algorithm families and LST retrieval methods for geostationary satellites were summarized in this dissertation. Literature relevant to the evaluation of satellite-based LSTs was also reviewed. All the existing methods are a valuable reference to develop the GOES LST product. The primary objective of this dissertation is the development of models for deriving consistent GOES LSTs with high spatial and high temporal coverage. Proper LST retrieval algorithms were studied

  4. Cloud tolerance of remote-sensing technologies to measure land surface temperature

    NASA Astrophysics Data System (ADS)

    Holmes, Thomas R. H.; Hain, Christopher R.; Anderson, Martha C.; Crow, Wade T.

    2016-08-01

    Conventional methods to estimate land surface temperature (LST) from space rely on the thermal infrared (TIR) spectral window and is limited to cloud-free scenes. To also provide LST estimates during periods with clouds, a new method was developed to estimate LST based on passive-microwave (MW) observations. The MW-LST product is informed by six polar-orbiting satellites to create a global record with up to eight observations per day for each 0.25° resolution grid box. For days with sufficient observations, a continuous diurnal temperature cycle (DTC) was fitted. The main characteristics of the DTC were scaled to match those of a geostationary TIR-LST product.This paper tests the cloud tolerance of the MW-LST product. In particular, we demonstrate its stable performance with respect to flux tower observation sites (four in Europe and nine in the United States), over a range of cloudiness conditions up to heavily overcast skies. The results show that TIR-based LST has slightly better performance than MW-LST for clear-sky observations but suffers an increasing negative bias as cloud cover increases. This negative bias is caused by incomplete masking of cloud-covered areas within the TIR scene that affects many applications of TIR-LST. In contrast, for MW-LST we find no direct impact of clouds on its accuracy and bias. MW-LST can therefore be used to improve TIR cloud screening. Moreover, the ability to provide LST estimates for cloud-covered surfaces can help expand current clear-sky-only satellite retrieval products to all-weather applications.

  5. A coupled force-restore model of surface temperature and soil moisture using the maximum entropy production model of heat fluxes

    NASA Astrophysics Data System (ADS)

    Huang, S.-Y.; Wang, J.

    2016-07-01

    A coupled force-restore model of surface soil temperature and moisture (FRMEP) is formulated by incorporating the maximum entropy production model of surface heat fluxes and including the gravitational drainage term. The FRMEP model driven by surface net radiation and precipitation are independent of near-surface atmospheric variables with reduced sensitivity to the uncertainties of model input and parameters compared to the classical force-restore models (FRM). The FRMEP model was evaluated using observations from two field experiments with contrasting soil moisture conditions. The modeling errors of the FRMEP predicted surface temperature and soil moisture are lower than those of the classical FRMs forced by observed or bulk formula based surface heat fluxes (bias 1 ~ 2°C versus ~4°C, 0.02 m3 m-3 versus 0.05 m3 m-3). The diurnal variations of surface temperature, soil moisture, and surface heat fluxes are well captured by the FRMEP model measured by the high correlations between the model predictions and observations (r ≥ 0.84). Our analysis suggests that the drainage term cannot be neglected under wet soil condition. A 1 year simulation indicates that the FRMEP model captures the seasonal variation of surface temperature and soil moisture with bias less than 2°C and 0.01 m3 m-3 and correlation coefficients of 0.93 and 0.9 with observations, respectively.

  6. Assessment of land surface temperature and heat fluxes over Delhi using remote sensing data.

    PubMed

    Chakraborty, Surya Deb; Kant, Yogesh; Mitra, Debashis

    2015-01-15

    Surface energy processes has an essential role in urban weather, climate and hydrosphere cycles, as well in urban heat redistribution. The research was undertaken to analyze the potential of Landsat and MODIS data in retrieving biophysical parameters in estimating land surface temperature & heat fluxes diurnally in summer and winter seasons of years 2000 and 2010 and understanding its effect on anthropogenic heat disturbance over Delhi and surrounding region. Results show that during years 2000-2010, settlement and industrial area increased from 5.66 to 11.74% and 4.92 to 11.87% respectively which in turn has direct effect on land surface temperature (LST) and heat fluxes including anthropogenic heat flux. Based on the energy balance model for land surface, a method to estimate the increase in anthropogenic heat flux (Has) has been proposed. The settlement and industrial areas has higher amounts of energy consumed and has high values of Has in all seasons. The comparison of satellite derived LST with that of field measured values show that Landsat estimated values are in close agreement within error of ±2 °C than MODIS with an error of ±3 °C. It was observed that, during 2000 and 2010, the average change in surface temperature using Landsat over settlement & industrial areas of both seasons is 1.4 °C & for MODIS data is 3.7 °C. The seasonal average change in anthropogenic heat flux (Has) estimated using Landsat & MODIS is up by around 38 W/m(2) and 62 W/m(2) respectively while higher change is observed over settlement and concrete structures. The study reveals that the dynamic range of Has values has increased in the 10 year period due to the strong anthropogenic influence over the area. The study showed that anthropogenic heat flux is an indicator of the strength of urban heat island effect, and can be used to quantify the magnitude of the urban heat island effect. PMID:24360191

  7. Simultaneous measurements of skin sea surface temperature and sea surface emissivity from a single thermal imagery.

    PubMed

    Yoshimori, Kyu; Tamba, Sumio; Yokoyama, Ryuzo

    2002-08-20

    A novel method, to our knowledge, to measure simultaneously the thermal emissivity and skin temperature of a sea surface has been developed. The proposed method uses an infrared image that includes a sea surface and a reference object located near the surface. By combining this image with sky radiation temperature, we retrieve both skin sea surface temperature and sea surface emissivity from the single infrared image. Because the method requires no knowledge of thermal radiative properties of actual sea surfaces, it can be used even for a contaminated sea surface whose emissivity is hard to determine theoretically, e.g., oil slicks or slicks produced by biological wastes. Experimental results demonstrate that the estimated emissivity agrees with the theoretical prediction and, also, the recovered temperature distribution of skin sea surface has no appreciable high-temperature area that is due to reflection of the reference object. The method allows the acquisition of match-up data of radiometric sea surface temperatures that precisely correspond to the satellite observable data. PMID:12206200

  8. Electromagnetic Probes of Metal and Ceramic Surfaces at Low Temperature.

    NASA Astrophysics Data System (ADS)

    Rzchowski, Mark Steven

    1988-12-01

    This thesis presents, in three parts, topics dealing with the low temperature electro-magnetic surface properties of metals and ceramics. Part I discusses the development and operation of an apparatus to spatially resolve metallic surface potentials as a function of temperature between 2.8K and room temperature. This experiment operates under UHV conditions with a voltage resolution of 1 millivolt and a spatial resolution of 1200 microns. We use this equipment to search for temperature dependent changes in spatial fluctuations of the surface potential. A screening of these fluctuations by a surface conducting layer is suggested by the experiments of Lockhart, Witteborn, and Fairbank, who reported temperature dependent shielding of random electric fields inside a copper tube. Sharp changes with temperature in the microwave surface conductivity of copper and aluminum have also been reported. We have found some aluminum samples to be contaminated with sufficient tin to explain recent microwave results as superconducting impurity transitions. For copper, where both increased and decreased conductivities have been reported, we explain increasing conductivity results in the same way. The present experiment measures surface potential directly, but shows no evidence of temperature dependent shielding. Part II of this thesis presents a calculation of random fields outside a metal surface and their effect on TOF spectroscopy. We calculate the statistical properties of the fields in one-dimensional and cylindrical geometries, then use these results to investigate TOF effects. Calculated quantities include the autocovariance function of the potential, the rms electric field, corrections to the free particle time of flight, and the mean minimum energy required to transit the random potential. The results compare well with our numerical simulations, and with the available experimental data. In part III we investigate the 9.12 GHz complex surface impedance of bulk and thin film

  9. Microwave Imager Measures Sea Surface Temperature Through Clouds

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image was acquired over Tropical Atlantic and U.S. East Coast regions on Aug. 22 - Sept. 23, 1998. Cloud data were collected by the Geostationary Operational Environmental Satellite (GOES). Sea Surface Temperature (SST) data were collected aboard the NASA/NASDA Tropical Rainfall Measuring Mission (TRMM) satellite by The TRMM Microwave Imager (TMI). TMI is the first satellite microwave sensor capable of accurately measuring sea surface temperature through clouds, as shown in this scene. For years scientists have known there is a strong correlation between sea surface temperature and the intensity of hurricanes. But one of the major stumbling blocks for forecasters has been the precise measurement of those temperatures when a storm begins to form. In this scene, clouds have been made translucent to allow an unobstructed view of the surface. Notice Hurricane Bonnie approaching the Carolina Coast (upper left) and Hurricane Danielle following roughly in its path (lower right). The ocean surface has been falsely colored to show a map of water temperature--dark blues are around 75oF, light blues are about 80oF, greens are about 85oF, and yellows are roughly 90oF. A hurricane gathers energy from warm waters found at tropical latitudes. In this image we see Hurricane Bonnie cross the Atlantic, leaving a cooler trail of water in its wake. As Hurricane Danielle followed in Bonnie's path, the wind speed of the second storm dropped markedly, as available energy to fuel the storm dropped off. But when Danielle left Bonnie's wake, wind speeds increased due to temperature increases in surface water around the storm. As a hurricane churns up the ocean, it's central vortex draws surface heat and water into the storm. That suction at the surface causes an upwelling of deep water. At depth, tropical ocean waters are significantly colder than water found near the surface. As they're pulled up to meet the storm, those colder waters essentially leave a footprint in the storm's wake

  10. Surface temperatures of insulated glazing units: Infrared thermography laboratory measurements

    SciTech Connect

    Griffith, B.T.; Tuerler, D.; Arasteh, D.

    1995-12-01

    Data are presented for the distribution of surface temperatures on the warm-side surface of seven different insulated glazing units. Surface temperatures are measured using infrared thermography and an external referencing technique. This technique allows detailed mapping of surface temperatures that is non-intrusive. The glazings were placed between warm and cold environmental chambers that were operated at conditions corresponding to standard design conditions for winter heating. The temperatures conditions are 2 1.1{degrees}C (70{degrees}F) and -17.8{degrees}C (0{degrees}F) on the warm and cold sides, respectively. Film coefficients varied somewhat with average conditions of about 7.6 W/m{sup 2}{circ}K (1.34 Btu/h-ft{sup 2}{circ}{degrees}F) for the warm-side and 28.9 W/m{sup 2}{circ}K (5.1 Btu/h{circ}ft{sup 2}{circ}{degrees}F) for the cold-side. Surface temperature data are plotted for the vertical distribution along the centerline of the IG and for the horizontal distribution along the centerline. This paper is part of larger collaborative effort that studied the same set of glazings.

  11. Fiber-Optic Surface Temperature Sensor Based on Modal Interference.

    PubMed

    Musin, Frédéric; Mégret, Patrice; Wuilpart, Marc

    2016-01-01

    Spatially-integrated surface temperature sensing is highly useful when it comes to controlling processes, detecting hazardous conditions or monitoring the health and safety of equipment and people. Fiber-optic sensing based on modal interference has shown great sensitivity to temperature variation, by means of cost-effective image-processing of few-mode interference patterns. New developments in the field of sensor configuration, as described in this paper, include an innovative cooling and heating phase discrimination functionality and more precise measurements, based entirely on the image processing of interference patterns. The proposed technique was applied to the measurement of the integrated surface temperature of a hollow cylinder and compared with a conventional measurement system, consisting of an infrared camera and precision temperature probe. As a result, the optical technique is in line with the reference system. Compared with conventional surface temperature probes, the optical technique has the following advantages: low heat capacity temperature measurement errors, easier spatial deployment, and replacement of multiple angle infrared camera shooting and the continuous monitoring of surfaces that are not visually accessible. PMID:27483271

  12. Geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  14. Applications of Thin Film Thermocouples for Surface Temperature Measurement

    NASA Technical Reports Server (NTRS)

    Martin, Lisa C.; Holanda, Raymond

    1994-01-01

    Thin film thermocouples provide a minimally intrusive means of measuring surface temperature in hostile, high temperature environments. Unlike wire thermocouples, thin films do not necessitate any machining of the surface, therefore leaving intact its structural integrity. Thin films are many orders of magnitude thinner than wire, resulting in less disruption to the gas flow and thermal patterns that exist in the operating environment. Thin film thermocouples have been developed for surface temperature measurement on a variety of engine materials. The sensors are fabricated in the NASA Lewis Research Center's Thin Film Sensor Lab, which is a class 1000 clean room. The thermocouples are platinum-13 percent rhodium versus platinum and are fabricated by the sputtering process. Thin film-to-leadwire connections are made using the parallel-gap welding process. Thermocouples have been developed for use on superalloys, ceramics and ceramic composites, and intermetallics. Some applications of thin film thermocouples are: temperature measurement of space shuttle main engine turbine blade materials, temperature measurement in gas turbine engine testing of advanced materials, and temperature and heat flux measurements in a diesel engine. Fabrication of thin film thermocouples is described. Sensor durability, drift rate, and maximum temperature capabilities are addressed.

  15. High temperature limits in vivo pollen tube growth rates by altering diurnal carbohydrate balance in field-grown Gossypium hirsutum pistils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has recently been reported that high temperature slows in vivo pollen tube growth rates in Gossypium hirsutum pistils under field conditions. Although numerous physical and biochemical pollen-pistil interactions are necessary for in vivo pollen tube growth to occur, studies investigating the infl...

  16. Surface temperatures and temperature gradient features of the US Gulf Coast waters

    NASA Technical Reports Server (NTRS)

    Huh, O. K.; Rouse, L. J., Jr.; Smith, G. W.

    1977-01-01

    Satellite thermal infrared data on the Gulf of Mexico show that a seasonal cycle exists in the horizontal surface temperature structure. In the fall, the surface temperatures of both coastal and deep waters are nearly uniform. With the onset of winter, atmospheric cold fronts, which are accompanied by dry, low temperature air and strong winds, draw heat from the sea. A band of cooler water forming on the inner shelf expands, until a thermal front develops seaward along the shelf break between the cold shelf waters and the warmer deep waters of the Gulf. Digital analysis of the satellite data was carried out in an interactive mode using a minicomputer and software. A time series of temperature profiles illustrates the temporal and spatial changes in the sea-surface temperature field.

  17. Rectification of the Diurnal Cycle and the Impact of Islands on the Tropical Climate

    NASA Astrophysics Data System (ADS)

    Cronin, T. W.; Emanuel, K.

    2012-12-01

    Tropical islands are observed to be rainier than nearby ocean areas, and rainfall over the islands of the Maritime Continent plays an important role in the atmospheric general circulation. Convective heating over tropical islands is also strongly modulated by the diurnal cycle of solar insolation and surface enthalpy fluxes, and convective parameterizations in general circulation models are known to reproduce the phase and amplitude of the observed diurnal cycle of convection rather poorly. Connecting these ideas suggests that poor representation of the diurnal cycle of convection and precipitation over tropical islands in climate models may be a significant source of model biases. Here, we explore how a highly idealized island, which differs only in heat capacity from the surrounding ocean, could rectify the diurnal cycle and impact the tropical climate, especially the spatial distribution of rainfall. We perform simulations of radiative-convective equilibrium with the System for Atmospheric Modeling cloud-system-resolving model, with interactive surface temperature and a varied surface heat capacity. For the case of relatively small-scale simulations, where a shallow (~5 cm) slab-ocean "swamp island" surface is embedded in a deeper (~1 m) slab-ocean domain, the precipitation rate over the island is more than double the domain average value, with island rainfall occurring primarily in a strong regular convective event each afternoon. In addition to this island precipitation enhancement, the upper troposphere also warms with the inclusion of a low- heat capacity island. We discuss two radiative mechanisms that contribute to both island precipitation enhancement and free tropospheric warming, by producing a top-of-atmosphere radiative surplus over the island. The first radiative mechanism is a clear-sky effect, related to nonlinearities in the surface energy budget, and differences in how surface energy balance is achieved over surfaces of different heat capacities

  18. Land surface temperature measurements from EOS MODIS data

    NASA Technical Reports Server (NTRS)

    Wan, Zhengming

    1994-01-01

    A generalized split-window method for retrieving land-surface temperature (LST) from AVHRR and MODIS data has been developed. Accurate radiative transfer simulations show that the coefficients in the split-window algorithm for LST must depend on the viewing angle, if we are to achieve a LST accuracy of about 1 K for the whole scan swath range (+/-55.4 deg and +/-55 deg from nadir for AVHRR and MODIS, respectively) and for the ranges of surface temperature and atmospheric conditions over land, which are much wider than those over oceans. We obtain these coefficients from regression analysis of radiative transfer simulations, and we analyze sensitivity and error by using results from systematic radiative transfer simulations over wide ranges of surface temperatures and emissivities, and atmospheric water vapor abundance and temperatures. Simulations indicated that as atmospheric column water vapor increases and viewing angle is larger than 45 deg it is necessary to optimize the split-window method by separating the ranges of the atmospheric column water vapor and lower boundary temperature, and the surface temperature into tractable sub-ranges. The atmospheric lower boundary temperature and (vertical) column water vapor values retrieved from HIRS/2 or MODIS atmospheric sounding channels can be used to determine the range where the optimum coefficients of the split-window method are given. This new LST algorithm not only retrieves LST more accurately but also is less sensitive than viewing-angle independent LST algorithms to the uncertainty in the band emissivities of the land-surface in the split-window and to the instrument noise.

  19. Does the accuracy of fine-scale water level measurements by vented pressure transducers permit for diurnal evapotranspiration estimation?

    NASA Astrophysics Data System (ADS)

    Gribovszki, Zoltán; Kalicz, Péter; Szilágyi, József

    2013-04-01

    Evapotranspiration (ET) estimation methods based on diurnal water level (surface or groundwater) fluctuations are sensitive to measurement accuracy (McLaughlin and Cohen, 2011; Cuevas et al., 2010). Water level fluctuations are often measured by pressure transducers of varying design and precision. Available total pressure transducers require a compensation for barometric pressure change supplied by barometric pressure transducers. Recently McLaughlin and Cohen (2011) as well as Cuevas et al. (2010) analyzed the 'thermal artifacts' of such transducer-pair data questioning the applicability of sub-daily water level measurements in non-buffered thermal mode for diurnal ET estimation. Similar problems should not, in principle, occur for so-called vented pressure transducers. With the help of ancillary manual measurements, this study verifies the accuracy of vented pressure transducer obtained ultra-fine scale (temporal resolution of 1-10 min) stream- and groundwater level data. Thermal effects were examined by a statistical analysis of concurrent water level and temperature data. The results support the thermal artifact-free nature of vented pressure transducers and therefore their suitability for diurnal ET estimation purposes when proper maintenance and periodic calibrations are provided. In the lack of such measures, diurnal temperature changes can induce errors in vented pressure transducer readings as well.

  20. High-Temperature Surface-Acoustic-Wave Transducer

    NASA Technical Reports Server (NTRS)

    Zhao, Xiaoliang; Tittmann, Bernhard R.

    2010-01-01

    Aircraft-engine rotating equipment usually operates at high temperature and stress. Non-invasive inspection of microcracks in those components poses a challenge for the non-destructive evaluation community. A low-profile ultrasonic guided wave sensor can detect cracks in situ. The key feature of the sensor is that it should withstand high temperatures and excite strong surface wave energy to inspect surface/subsurface cracks. As far as the innovators know at the time of this reporting, there is no existing sensor that is mounted to the rotor disks for crack inspection; the most often used technology includes fluorescent penetrant inspection or eddy-current probes for disassembled part inspection. An efficient, high-temperature, low-profile surface acoustic wave transducer design has been identified and tested for nondestructive evaluation of structures or materials. The development is a Sol-Gel bismuth titanate-based surface-acoustic-wave (SAW) sensor that can generate efficient surface acoustic waves for crack inspection. The produced sensor is very thin (submillimeter), and can generate surface waves up to 540 C. Finite element analysis of the SAW transducer design was performed to predict the sensor behavior, and experimental studies confirmed the results. One major uniqueness of the Sol-Gel bismuth titanate SAW sensor is that it is easy to implement to structures of various shapes. With a spray coating process, the sensor can be applied to surfaces of large curvatures. Second, the sensor is very thin (as a coating) and has very minimal effect on airflow or rotating equipment imbalance. Third, it can withstand temperatures up to 530 C, which is very useful for engine applications where high temperature is an issue.

  1. Orientational order at finite temperature on curved surfaces

    NASA Astrophysics Data System (ADS)

    Brito, Carolina; Vitelli, Vincenzo; Dauchot, Olivier

    2016-03-01

    We study the effect of thermal fluctuations in the XY model on surfaces with unequal principal curvatures. Unlike Gaussian curvature that typically frustrates orientational order, the extrinsic curvature of the surface can act as a local field that promotes long-range order at low temperature. We find numerically that the transition from the high temperature isotropic phase to the true long-range ordered phase is characterized by critical exponents consistent with those of the flat space Ising model in two dimensions, up to finite size effects. Our results suggest a versatile strategy to achieve geometric control of liquid crystal order by suitable design of the underlying curvature of a substrate.

  2. Long-term changes in sea surface temperatures

    SciTech Connect

    Parker, D.E.

    1994-12-31

    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.

  3. Japanese Whaling Ships' Sea Surface Temperatures 1946-84.

    NASA Astrophysics Data System (ADS)

    Mierzejewska, Anna W.; Wu, Zhongxiang; Newell, Reginald E.; Miyashita, Tomio

    1997-03-01

    Japanese whaling ship data, a homogeneous dataset mainly covering the southern high-latitude oceans, may be used to fill in gaps in recent sea surface temperature datasets, contributing a fair number of additional observations in this area. The Japanese whaling ship data are treated separately here for the period 1946-84, and they show no significant temperature changes during this period in the main fishing region of 60°-70°S or in the west Pacific warm pool.

  4. Temperature dependence of surface photovoltage of bulk semiconductors and the effect of surface passivation

    NASA Astrophysics Data System (ADS)

    Datta, Shouvik; Gokhale, M. R.; Shah, A. P.; Arora, B. M.; Kumar, Shailendra

    2000-12-01

    Surface photovoltage (SPV) of n-GaAs decreases both above and below a certain transition temperature. We explain this phenomenon in terms of a Schottky contact based model and relative dominance of thermal and nonthermal parts of the dark current. This also explains the observed increase of SPV of p-GaAs below room temperature. Our analysis is further confirmed from the temperature dependence of the SPV measurements on p-InP and n-InP samples. Surface passivation is seen to lower the transition temperature of n-GaAs.

  5. An Analytic Function of Lunar Surface Temperature for Exospheric Modeling

    NASA Technical Reports Server (NTRS)

    Hurley, Dana M.; Sarantos, Menelaos; Grava, Cesare; Williams, Jean-Pierre; Retherford, Kurt D.; Siegler, Matthew; Greenhagen, Benjamin; Paige, David

    2014-01-01

    We present an analytic expression to represent the lunar surface temperature as a function of Sun-state latitude and local time. The approximation represents neither topographical features nor compositional effects and therefore does not change as a function of selenographic latitude and longitude. The function reproduces the surface temperature measured by Diviner to within +/-10 K at 72% of grid points for dayside solar zenith angles of less than 80, and at 98% of grid points for nightside solar zenith angles greater than 100. The analytic function is least accurate at the terminator, where there is a strong gradient in the temperature, and the polar regions. Topographic features have a larger effect on the actual temperature near the terminator than at other solar zenith angles. For exospheric modeling the effects of topography on the thermal model can be approximated by using an effective longitude for determining the temperature. This effective longitude is randomly redistributed with 1 sigma of 4.5deg. The resulting ''roughened'' analytical model well represents the statistical dispersion in the Diviner data and is expected to be generally useful for future models of lunar surface temperature, especially those implemented within exospheric simulations that address questions of volatile transport.

  6. Innovative approach to retrieve land surface emissivity and land surface temperature in areas of highly dynamic emissivity changes by using thermal infrared data

    NASA Astrophysics Data System (ADS)

    Heinemann, Sascha; Muro, Javier; Burkart, Andreas; Schultz, Johannes; Thonfeld, Frank; Menz, Gunter

    2016-04-01

    The land surface temperature (LST) is an extremely significant parameter in order to understand the processes of energetic interactions between the Earth's surface and the atmosphere. This knowledge is significant for various environmental research questions, particularly with regard to climate change. The current challenge is to reduce the higher deviations during daytime especially for bare areas with a maximum of 5.7 Kelvin. These temperature differences are time and vegetation cover dependent. This study shows an innovative approach to retrieve land surface emissivity (LSE) and LST by using thermal infrared (TIR) data from satellite sensors, such as SEVIRI and AATSR. So far there are no methods to derive LSE/LST particularly in areas of highly dynamic emissivity changes. Therefore especially for regions with large surface temperature amplitude in the diurnal cycle such as bare and uneven soil surfaces but also for regions with seasonal changes in vegetation cover including various surface areas such as grassland, mixed forests or agricultural land different methods were investigated to identify the most appropriate one. The LSE is retrieved by using the day/night Temperature-Independent Spectral Indices (TISI) method, while the Generalised Split-Window (GSW) method is used to retrieve the LST. Nevertheless different GSW algorithms show that equal LSEs lead to large LST differences. For bare surfaces during daytime the difference is about 6 Kelvin. Additionally LSE is also measured using a NDVI-based threshold method (NDVITHM) to distinguish between soil, dense vegetation cover and pixel composed of soil and vegetation. The data used for this analysis were derived from MODIS TIR. The analysis is implemented with IDL and an intercomparison is performed to determine the most effective methods. To compensate temperature differences between derived and ground truth data appropriate correction terms, by comparing derived LSE/LST data with ground-based measurements

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

    NASA Astrophysics Data System (ADS)

    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.

  8. ESTIMATING SUBPIXEL SURFACE TEMPERATURES AND ENERGY FLUXES FROM THE VEGETATION INDEX-RADIOMETRIC TEMPERATURE RELATIONSHIP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Routine (i.e., daily to weekly) monitoring of surface energy fluxes, particularly evapotranspiration (ET), using satellite observations of radiometric surface temperature has not been feasible at high pixel resolution because of the low frequency in satellite coverage over the region of interest (i...

  9. The Land Surface Temperature Impact to Land Cover Types

    NASA Astrophysics Data System (ADS)

    Ibrahim, I.; Abu Samah, A.; Fauzi, R.; Noor, N. M.

    2016-06-01

    Land cover type is an important signature that is usually used to understand the interaction between the ground surfaces with the local temperature. Various land cover types such as high density built up areas, vegetation, bare land and water bodies are areas where heat signature are measured using remote sensing image. The aim of this study is to analyse the impact of land surface temperature on land cover types. The objectives are 1) to analyse the mean temperature for each land cover types and 2) to analyse the relationship of temperature variation within land cover types: built up area, green area, forest, water bodies and bare land. The method used in this research was supervised classification for land cover map and mono window algorithm for land surface temperature (LST) extraction. The statistical analysis of post hoc Tukey test was used on an image captured on five available images. A pixel-based change detection was applied to the temperature and land cover images. The result of post hoc Tukey test for the images showed that these land cover types: built up-green, built up-forest, built up-water bodies have caused significant difference in the temperature variation. However, built up-bare land did not show significant impact at p<0.05. These findings show that green areas appears to have a lower temperature difference, which is between 2° to 3° Celsius compared to urban areas. The findings also show that the average temperature and the built up percentage has a moderate correlation with R2 = 0.53. The environmental implications of these interactions can provide some insights for future land use planning in the region.

  10. Land surface temperature measurements for EOS MODIS data

    NASA Technical Reports Server (NTRS)

    Wan, Zhengming

    1994-01-01

    Work accomplished includes: Beta delivery 1 of the MODIS LST product; the first version of MODIS LST ATBD; update of the atmospheric radiative transfer code ATRAD; the development of a new approach look-up table method; and improvement of the TIR spectrometer. Preliminary feasibility analysis of the look-up table approach is presented in terms of showing the effects on the TIR radiance at the top of the atmosphere of the stratospheric and upper atmospheric temperature profiles, the surface emissivity and temperature, the lower atmospheric temperature and water vapor profiles, and the viewing angle.

  11. Global surface temperature changes since the 1850s

    SciTech Connect

    Jones, P.D.

    1996-12-31

    Temperature data from land and marine areas form the basis for many studies of climatic variations on local, regional and hemispheric scales, and the global mean temperature is a fundamental measure of the state of the climate system. In this paper it is shown that the surface temperature of the globe has warmed by about 0.5{degrees}C since the mid-nineteenth century. This is an important part of the evidence in the {open_quote}global warming{close_quote} debate. How certain are we about the magnitude of the warming? Where has it been greatest? In this paper, these and related issues will be addressed.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Surface temperature measurement of insulating glass units using infrared thermography

    SciTech Connect

    Elmahdy, H.

    1996-12-31

    Infrared (IR) thermography is a process to produce, by means of an infrared scanner, thermal images of surfaces by detecting the radiation emitted from the surfaces. The application of IR thermography as a diagnostic tool in building science assists in determining existing anomalies in the building envelope and other building components. In this paper, IR thermography is used to compare the glass surface temperatures of insulating glass (IG) units made with two types of spacer bar (metal and silicone foam) and different gap widths. The results from this research are compared with data obtained from another research laboratory using a different IR scanner and also with data from finite-element computer modeling. All the tests and simulations were performed on identical IG units. Tests performed on seven IG units indicated that IR thermography could be used to assess the edge-of-glass temperature of IG units for the prediction of condensation resistance of the units. The image processing and analysis depend on the knowledge of accurate emissivity of the surfaces under investigation as well as other variables that affect the final thermal image (e.g., ambient temperature, relative humidity of air in the optical path, and the optical path length). The IR scanner records all the radiation (both direct and reflected) it sees either from the intended target or from any other radiative surfaces in its field of view (FOV). The vertical temperature profiles of all the tested units showed considerable reduction of temperature at the bottom section of the IG unit. The degree of temperature reduction is affected by the type of spacer bar material and the gap thickness.

  14. Diurnal Variation of Precipitation During MC3E Campaign

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Wu, Di; Matsui, Toshi; Peters-Lidard, Christa; Hou, Arthur; Rienecker, Michele

    2012-01-01

    The diurnal variation of precipitation processes in the United States (US) is well recognized but incompletely understood (Cabone et al. 2002). The diurnal cycle of precipitation has been studied using surface rainfall data, radar reflectivity data, and satellite-derived cloudiness and precipitation (Wallace 1975; Dai et al. 1999; Carbone et al. 2002; Carbone and Tuttle, 2008; Parker and Ahijevych, 2007; Matsui et al. 2010 and others). These observations indicate that the summer-time precipitation most of the North America and typically feature late-afternoon precipitation maxima. These diurnal variation of precipitation can also be generally categorized into three different types: 1) afternoon rainfall maxima due to mesoscale and local circulations over the south and east of the Mississippi and Ohio valleys, 2) nocturnal rainfall maxima from eastward-propagating mesoscale convective systems (MCSs) over the Lee side of Rocky Mountain regions and 3) afternoon rainfall maxima in the Appalachian Mountains, and then propagate eastward toward the coast. The main objective of this paper is to use a regional cloud-scale model with very high-resolution (i.e., WRF) to examine the WRF ability to simulate diurnal variation of precipitation. Specifically, the study will (1) identify the physical processes responsible to diurnal variation of precipitation, (2) examine the sensitivity of resolution (2, 6, 18, and 30 km) to model simulated diurnal variation of precipitation and (3) identify the relationships between microphysics and cumulus parameterization schemes.

  15. How do changes in the Diurnal Cycle affect Bi-stability and Climate Sensitivity in the Habitable Zone?

    NASA Astrophysics Data System (ADS)

    Boschi, R.; Valerio, L.

    2013-09-01

    In this study we deal with the effect of varying the length of the diurnal cycle on its bi-stability properties. By using a general circulation model, PlaSim, we consider several values for the diurnal cycle, from tidally locked, to that of 1 Earth day. For each value of the diurnal cycle, we slowly modulate the solar constant between 1510 and 1000 Wm-2 and perform a hysteresis experiment. It is found that the width of the bi-stable region, i.e. the range of climate states - determined here by changes in S* - which support two climatic attractors, reduces when the diurnal cycle is increased in length and disappears - signifying the merging of both attractors - for climates with a diurnal cycle greater than 180 days. Crucial to the loss of bi-stability is the longitudinally asymmetric distribution of solar radiation, incident on the planet's surface, leading to the development of equatorial sea-ice. For diurnal cycles where bi-stability is found, the longitudinally asymmetric heating is sufficiently compensated for by the strength of the zonal winds and the rate of solar distribution, which redistribute heat and maintain the meridional temperature gradient across all longitudes. Conversely, for mono-stable regimes, the energy transport associated with zonal winds becomes insufficient to compensate for the increase in the length of the diurnal cycle, resulting in large zonal temperature gradients along the equatorial band. Furthermore, the results found here confirm and reenforce the robustness of those found in Boschi et al (2013), showing that, for climates which support bistability, it may be possible to parameterise variables such as the material entropy production and the meridional heat transport in terms of the surface and emission temperatures, within reasonably well defined upper and lower bounds, even when considering a wide range of planetary rotation speeds and changes to the infrared opacity. This paves the way for the possibility of practically deducing

  16. Surface roughness change on sandstone induced by temperature increase

    NASA Astrophysics Data System (ADS)

    Vlcko, J.; Kompanikova, Z.; Gomez-Heras, M.; Greif, V.; Durmekova, T.; Brcek, M.

    2012-04-01

    Optical surface profilometer allows capturing the information necessary to provide 3D surface measurements in a single image acquisition with a vertical micrometric resolution. The surface topography can be used for analyses, such as roughness evaluation. In this research, roughness changes of two types of sandstone samples were studied before and after heating to 60, 200, 400, 600 and 800 °C. Measurements obtained were converted into 3D 5 mm x 5 mm (25 mm2) topographic maps with a resolution of 2.5 µm. Surface roughness parameter Sq represents quantifies roughness from the maximum deviation along a mean surface and it is calculated as the root mean squared of five peaks and valleys of the specimen using Gaussian filter and 0.80 mm cut-off. The high spatial resolution obtained from visible-light optical surface profilometer is an ideal tool for observing rock surface alterations caused by decay factors. The authors present complete original process of surface roughness determination on rock samples adopting the portable profilometer using free accessible software packages. The different stability of the fabric of sandstones from Králiky and Oravská Jasenica after heating is due to their different mineral composition and different ratio of minerals that are more or less chemically stable at high temperatures, their resistance to thermal stress and other textural factors related to the distribution of grains and matrix. Percentage of minerals chemically stable at higher temperature, such as quartz, calcite, illite and muscovite, in fresh sandstone samples from Králiky is approximately 48%. Conversely, sandstones from Oravská Jasenica have significantly greater percentage of minerals stable at higher temperatures, such as quartz, albite, orthoclase, muscovite, illite and calcite than of other, less stable, minerals such as chlorite, biotite and kaolinite. Hence, percentage of minerals stable at higher temperatures was approximately 81 %. The results show how the

  17. Modeling Near-Surface Temperatures at Martian Landing Sites

    NASA Technical Reports Server (NTRS)

    Martin, T. Z.; Bridges, N. T.; Murphy, J. R.

    2003-01-01

    We have developed a process for deriving near-surface (approx. 1m) temperatures for potential landing sites, based on observational parameters from MGS TES, Odyssey THEMIS, and a boundary layer model developed by Murphy for fitting Pathfinder meteorological measurements. Minimum nighttime temperatures at the MER landing sites can limit power available, and thus mission lifetime. Temperatures are derived based on thermal inertia, albedo, and opacity estimated for the Hematite site in Sinus Meridiani, using predictions of 1-m air temperatures from a one-dimensional atmospheric model. The Hematite site shows 9 % probability of landing at a location with nighttime temperatures below the 97 C value considered to be a practical limit for operations.

  18. Satellite observations of surface temperature patterns induced by synoptic circulation over the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Lensky, Itamar; Dayan, Uri

    2013-04-01

    Land Surface Temperature (LST) controls most physical and biological processes on Earth. Knowledge of the LST at high spatial resolution enables representation of different climate regimes. The main factors controlling LST are the seasonal and diurnal cycles, land cover, cloud cover, and atmospheric processes at several scales. Lensky and Dayan analyzed atmospheric processes at the topoclimatic scale, and the mesoscale (Lensky and Dayan 2011, 2012). Here we will demonstrate an analysis of the spatial distribution of LST anomaly as affected by typical synoptic circulation patterns over the Eastern Mediterranean (EM). LST anomaly is defined as the difference between daily and climatological LST. Using LST anomaly reduces the effects of land cover and the seasonal and diurnal cycles, enabling a better detection of surface temperature patterns induced by synoptic circulation. In this study we used all available 2000-2012 NASA daily MODIS LST data over the EM, together with NCEP/NCAR Reanalysis data of SLP, surface winds and Omega (at 700hPa). We will present two frequent synoptic circulation patterns as classified by Levy and Dayan (2008) to demonstrate the LST patterns induced by synoptic circulation over the EM. The first is the "Red Sea Trough" (RST) with eastern axis, which is an extension of a low surface pressure from a tropical depression toward the Red Sea, penetrating up north as far as Turkey. It migrates from south to north and mostly frequent during the autumn. The axis of the RST separates distinctively between regions of positive (warm) anomalies over Turkey and regions of negative anomalies (cold) over Egypt induced by the wind flow from both sides of the axis. The second synoptic circulation pattern is "shallow Cyprus low to the north", which is a disturbance of the polar front extending southward. This synoptic system some times migrates over the Mediterranean eastward toward the EM during the winter season. The strong northwesterly flow featuring the

  19. Surface heat flux parameterizations and tropical Pacific sea surface temperature simulations

    SciTech Connect

    Giese, B.S. University Corp. for Atmospheric Research, Boulder, CO ); Cayan, D.R. )

    1993-04-15

    The authors report on a study of the problem of getting good model results for the sea surface temperature in the tropical Pacific ocean. The tropical Pacific is particularly important because of its size, the large areas of warm surface temperature, its impact on global atmospheric circulation, and the fact that it serves as an indicator of climatic variations. To simulate sea surface temperature it is necessary to have an energy budget which fits into a general ocean circulation model. The main input, from solar flux, is not well known in the tropical Pacific. The authors use two different models to describe the latent flux and the radiative flux at the sea surface. Parameters of concern include the relative humidity, air-sea temperature difference, latent heat formulae, and radiative heat flux. They use these parameters in their models in different ways, and compare results with measurement sets from the Tropical Pacific.

  20. Temperature and strain-rate dependence of surface dislocation nucleation.

    PubMed

    Zhu, Ting; Li, Ju; Samanta, Amit; Leach, Austin; Gall, Ken

    2008-01-18

    Dislocation nucleation is essential to the plastic deformation of small-volume crystalline solids. The free surface may act as an effective source of dislocations to initiate and sustain plastic flow, in conjunction with bulk sources. Here, we develop an atomistic modeling framework to address the probabilistic nature of surface dislocation nucleation. We show the activation volume associated with surface dislocation nucleation is characteristically in the range of 1-10b3, where b is the Burgers vector. Such small activation volume leads to sensitive temperature and strain-rate dependence of the nucleation stress, providing an upper bound to the size-strength relation in nanopillar compression experiments. PMID:18232884

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

    NASA Technical Reports Server (NTRS)

    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. Modeling the Surface Temperature of Earth-like Planets

    NASA Astrophysics Data System (ADS)

    Vladilo, Giovanni; Silva, Laura; Murante, Giuseppe; Filippi, Luca; Provenzale, Antonello

    2015-05-01

    We introduce a novel Earth-like planet surface temperature model (ESTM) for habitability studies based on the spatial-temporal distribution of planetary surface temperatures. The ESTM adopts a surface energy balance model (EBM) complemented by: radiative-convective atmospheric column calculations, a set of physically based parameterizations of meridional transport, and descriptions of surface and cloud properties more refined than in standard EBMs. The parameterization is valid for rotating terrestrial planets with shallow atmospheres and moderate values of axis obliquity (ɛ ≲ 45{}^\\circ ). Comparison with a 3D model of atmospheric dynamics from the literature shows that the equator-to-pole temperature differences predicted by the two models agree within ≈ 5 K when the rotation rate, insolation, surface pressure and planet radius are varied in the intervals 0.5≲ {Ω }/{{{Ω }}\\oplus }≲ 2, 0.75≲ S/{{S}\\circ }≲ 1.25, 0.3≲ p/(1 bar)≲ 10, and 0.5≲ R/{{R}\\oplus }≲ 2, respectively. The ESTM has an extremely low computational cost and can be used when the planetary parameters are scarcely known (as for most exoplanets) and/or whenever many runs for different parameter configurations are needed. Model simulations of a test-case exoplanet (Kepler-62e) indicate that an uncertainty in surface pressure within the range expected for terrestrial planets may impact the mean temperature by ˜ 60 K. Within the limits of validity of the ESTM, the impact of surface pressure is larger than that predicted by uncertainties in rotation rate, axis obliquity, and ocean fractions. We discuss the possibility of performing a statistical ranking of planetary habitability taking advantage of the flexibility of the ESTM.

  3. Temperature Grid Sensor for the Measurement of Spatial Temperature Distributions at Object Surfaces

    PubMed Central

    Schäfer, Thomas; Schubert, Markus; Hampel, Uwe

    2013-01-01

    This paper presents results of the development and application of a new temperature grid sensor based on the wire-mesh sensor principle. The grid sensor consists of a matrix of 256 Pt1000 platinum chip resistors and an associated electronics that measures the grid resistances with a multiplexing scheme at high speed. The individual sensor elements can be spatially distributed on an object surface and measure transient temperature distributions in real time. The advantage compared with other temperature field measurement approaches such as infrared cameras is that the object under investigation can be thermally insulated and the radiation properties of the surface do not affect the measurement accuracy. The sensor principle is therefore suited for various industrial monitoring applications. Its applicability for surface temperature monitoring has been demonstrated through heating and mixing experiments in a vessel. PMID:23353141

  4. Effect of Surface Energy on Freezing Temperature of Water.

    PubMed

    Zhang, Yu; Anim-Danso, Emmanuel; Bekele, Selemon; Dhinojwala, Ali

    2016-07-13

    Previous studies have found that superhydrophobic surfaces are effective in delaying freezing of water droplets. However, the freezing process of water droplets on superhydrophobic surfaces depends on factors such as droplet size, surface area, roughness, and cooling rate. The role of surface energy, independent of any other parameters, in delaying freezing of water is not understood. Here, we have used infrared-visible sum frequency generation spectroscopy (SFG) to study the freezing of water next to solid substrates with water contact angles varying from 5° to 110°. We find that the freezing temperature of water decreases with increasing surface hydrophobicity only when the sample volume is small (∼10 μL). For a larger volume of water (∼300 μL), the freezing temperature is independent of surface energy. For water next to the surfaces with contact angle ≥54°, we observe a strong SFG peak associated with highly coordinated water. This research sheds new light on understanding the key factors in designing new anti-icing coatings. PMID:27314147

  5. Why the Diurnal Pressure Variation at Curiosity is so Large

    NASA Astrophysics Data System (ADS)

    Richardson, M. I.; Heavens, N. G.; Mischna, M. A.; Newman, C. E.; Wilson, R.; Team, M.

    2013-12-01

    The diurnal range of pressure observed by the Curiosity Rover Environmental Monitoring Station (REMS) is larger than that seen at any prior Martian landing site [Harri et al., JGR 2013]. Shortly after landing, the percentage diurnal variation was roughly 11%. This range compares with general circulation model (GCM) predictions at roughly 2-5 degrees resolution of 6-7%. In the GCM, the range is primarily due to the large scale thermal tides and equatorial Kelvin waves. However, the question of why the observed range was so much larger than the GCM-predicted range was the biggest early puzzle of the REMS observation campaign. A significant clue to the puzzle is provided by the fact that high resolution models (~<10 km resolution) can adequately capture the observed range, but that if these models are averaged over an area equivalent to the GCM grid cell size, they also simultaneously match the GCM-predicted ranges. The augmented range in pressure seen by REMS and also by the mesoscale models is thus a process operating on scales smaller than captured by the GCM. Indeed, the Gale Crater site is unique amongst Mars landing sites in the large degree of topographic relief on scales of ~10km. Using basic physical arguments and mesoscale modeling, we show that the augmented range of daily pressure variation measured by REMS is due to a process of hydrostatic adjustment in response to the daily cycle of air temperature. In the presence of a slope, a change in scale height (which depends only on the air temperature) demands a change in the horizontal gradient of surface pressure. Thus, during the warmer portion of the day, the pressure difference between two fixed points at different elevations along a slope will be smaller than that during the cooler portion. If the lower elevation point is held at fixed pressure, the upper point experiences a daily pressure cycle with higher pressure during the warmer daytime and lower during the cooler night. If instead, the domain

  6. High temperature growth of Pt on the Rh(111) surface

    NASA Astrophysics Data System (ADS)

    Duisberg, M.; Dräger, M.; Wandelt, K.; Gruber, E. L. D.; Schmid, M.; Varga, P.

    1999-08-01

    The epitaxial growth of Pt on the Rh(111) surface at 700 K was studied with AES, UPS, ISS and STM. From AES and ISS measurements a 2D growth mode is concluded at this substrate temperature. The morphology of the surface is studied by photoemission spectra of adsorbed Xe (PAX) and STM. A disperse distribution of the Pt atoms is suggested by PAX and is consistent with an incorporation of these atoms into the first substrate layer. Atomically and chemically resolved STM measurements confirm these conclusions. The interaction of CO with the surface alloy is investigated by UPS. The CO-induced features in UP spectra show significant differences in the peak positions and shape between the clean substrate and the surface precovered with different amounts of Pt. The CO induced emissions are, thus, used for a quantitative titration of Pt on the Rh surface.

  7. Relating temperature dependence of atom scattering spectra to surface corrugation.

    PubMed

    Hayes, W W; Manson, J R

    2011-12-01

    It is suggested that a measurement of the temperature dependence of the most probable intensity of energy-resolved atom-surface scattering spectra can reveal the strength of the surface corrugation. To support this conjecture, a classical mechanical theory of atom scattering from a corrugated surface, valid in the weak corrugation limit, is developed. The general result for the scattering probability is expressed in terms of spatial integrals over the impact parameter within a surface unit cell. For the case of a one-dimensional corrugation, approximate expressions for the scattering probability are obtained in terms of analytic closed form expressions. As an indicator of its relation to experimental measurements, calculations using a one-dimensional corrugation model are compared with data for Ar scattering from a molten Ga surface and an approximate value of the corrugation height parameter is extracted. PMID:22085838

  8. Climate change signal analysis for Northeast Asian surface temperature

    NASA Astrophysics Data System (ADS)

    Lee, Jeong-Hyeong; Kim, Byungsoo; Sohn, Keon-Tae; Kown, Won-Tae; Min, Seung-Ki

    2005-03-01

    Climate change detection, attribution, and prediction were studied for the surface temperature in the Northeast Asian region using NCEP/NCAR reanalysis data and three coupled-model simulations from ECHAM4/OPYC3, HadCM3, and CCCma GCMs (Canadian Centre for Climate Modeling and Analysis general circulation model). The Bayesian fingerprint approach was used to perform the detection and attribution test for the anthropogenic climate change signal associated with changes in anthropogenic carbon dioxide (CO2) and sulfate aerosol (SO{4/2-}) concentrations for the Northeast Asian temperature. It was shown that there was a weak anthropogenic climate change signal in the Northeast Asian temperature change. The relative contribution of CO2 and SO{4/2-} effects to total temperature change in Northeast Asia was quantified from ECHAM4/OPYC3 and CCCma GCM simulations using analysis of variance. For the observed temperature change for the period of 1959 1998, the CO2 effect contributed 10% 21% of the total variance and the direct cooling effect of SO{4/2-} played a less important role (0% 7%) than the CO2 effect. The prediction of surface temperature change was estimated from the second CO2+SO{4/2-} scenario run of ECHAM4/OPYC3 which has the least error in the simulation of the present-day temperature field near the Korean Peninsula. The result shows that the area-mean surface temperature near the Korean Peninsula will increase by about 1.1° by the 2040s relative to the 1990s.

  9. Two Surface Temperature Retrieval Methods Compared Over Agricultural Lands

    NASA Technical Reports Server (NTRS)

    French, Andrew N.; Schmugge, Thomas J.; Jacob, Frederic; Ogawa, Kenta; Houser, Paul R. (Technical Monitor)

    2002-01-01

    Accurate, spatially distributed surface temperatures are required for modeling evapotranspiration (ET) over agricultural fields under wide ranging conditions, including stressed and unstressed vegetation. Modeling approaches that use surface temperature observations, however, have the burden of estimating surface emissivities. Emissivity estimation, the subject of much recent research, is facilitated by observations in multiple thermal infrared bands. But it is nevertheless a difficult task. Using observations from a multiband thermal sensor, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), estimated surface emissivities and temperatures are retrieved in two different ways: the temperature emissivity separation approach (TES) and the normalized emissivity approach (NEM). Both rely upon empirical relationships, but the assumed relationships are different. TES relies upon a relationship between the minimum spectral emissivity and the range of observed emissivities. NEM relies upon an assumption that at least one thermal band has a pre-determined emissivity (close to 1.0). The benefits and consequences of each approach will be demonstrated for two different landscapes: one in central Oklahoma, USA and another in southern New Mexico.

  10. Fermi surfaces and energy gaps of high-temperature superconductors

    SciTech Connect

    Shen, Z.X.; Dessau, D.S.

    1994-12-31

    In this short paper, the authors describe their recent experimental results from high-temperature superconductors. In the normal state, the data reveals interesting features of the Fermi surfaces and low energy excitations near the Fermi level. In the superconducting state, the data shows a very strong anisotropy in the superconducting gap.

  11. Applications of Land Surface Temperature from Microwave Observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land surface temperature (LST) is a key input for physically-based retrieval algorithms of hydrological states and fluxes. Yet, it remains a poorly constrained parameter for global scale studies. The main two observational methods to remotely measure T are based on thermal infrared (TIR) observation...

  12. Enzyme surface rigidity tunes the temperature dependence of catalytic rates.

    PubMed

    Isaksen, Geir Villy; Åqvist, Johan; Brandsdal, Bjørn Olav

    2016-07-12

    The structural origin of enzyme adaptation to low temperature, allowing efficient catalysis of chemical reactions even near the freezing point of water, remains a fundamental puzzle in biocatalysis. A remarkable universal fingerprint shared by all cold-active enzymes is a reduction of the activation enthalpy accompanied by a more negative entropy, which alleviates the exponential decrease in chemical reaction rates caused by lowering of the temperature. Herein, we explore the role of protein surface mobility in determining this enthalpy-entropy balance. The effects of modifying surface rigidity in cold- and warm-active trypsins are demonstrated here by calculation of high-precision Arrhenius plots and thermodynamic activation parameters for the peptide hydrolysis reaction, using extensive computer simulations. The protein surface flexibility is systematically varied by applying positional restraints, causing the remarkable effect of turning the cold-active trypsin into a variant with mesophilic characteristics without changing the amino acid sequence. Furthermore, we show that just restraining a key surface loop causes the same effect as a point mutation in that loop between the cold- and warm-active trypsin. Importantly, changes in the activation enthalpy-entropy balance of up to 10 kcal/mol are almost perfectly balanced at room temperature, whereas they yield significantly higher rates at low temperatures for the cold-adapted enzyme. PMID:27354533

  13. Three-way partitioning of sea surface temperature measurement error

    NASA Technical Reports Server (NTRS)

    Chelton, D.

    1983-01-01

    Given any set of three 2 degree binned anomaly sea surface temperature (SST) data sets by three different sensors, estimates of the mean square error of each sensor estimate is made. The above formalism performed on every possible triplet of sensors. A separate table of error estimates is then constructed for each sensor.

  14. DISAGGREGATION OF GOES-LAND SURFACE TEMPERATURES USING MODIS OBSERVATIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  15. Instrument accurately measures small temperature changes on test surface

    NASA Technical Reports Server (NTRS)

    Harvey, W. D.; Miller, H. B.

    1966-01-01

    Calorimeter apparatus accurately measures very small temperature rises on a test surface subjected to aerodynamic heating. A continuous thin sheet of a sensing material is attached to a base support plate through which a series of holes of known diameter have been drilled for attaching thermocouples to the material.

  16. Enzyme surface rigidity tunes the temperature dependence of catalytic rates

    PubMed Central

    Isaksen, Geir Villy; Åqvist, Johan; Brandsdal, Bjørn Olav

    2016-01-01

    The structural origin of enzyme adaptation to low temperature, allowing efficient catalysis of chemical reactions even near the freezing point of water, remains a fundamental puzzle in biocatalysis. A remarkable universal fingerprint shared by all cold-active enzymes is a reduction of the activation enthalpy accompanied by a more negative entropy, which alleviates the exponential decrease in chemical reaction rates caused by lowering of the temperature. Herein, we explore the role of protein surface mobility in determining this enthalpy–entropy balance. The effects of modifying surface rigidity in cold- and warm-active trypsins are demonstrated here by calculation of high-precision Arrhenius plots and thermodynamic activation parameters for the peptide hydrolysis reaction, using extensive computer simulations. The protein surface flexibility is systematically varied by applying positional restraints, causing the remarkable effect of turning the cold-active trypsin into a variant with mesophilic characteristics without changing the amino acid sequence. Furthermore, we show that just restraining a key surface loop causes the same effect as a point mutation in that loop between the cold- and warm-active trypsin. Importantly, changes in the activation enthalpy–entropy balance of up to 10 kcal/mol are almost perfectly balanced at room temperature, whereas they yield significantly higher rates at low temperatures for the cold-adapted enzyme. PMID:27354533

  17. Investigation of Aerodynamic and Aerodynamic and Radiometric Land Surface Temperatures

    NASA Technical Reports Server (NTRS)

    Crago, Richard D.; Friedl, Mark; Kustas, William; Wang, Ye-Qiao

    2003-01-01

    The overall goal of the project was to reconcile the difference between T(sub s,r) and T(sub aero), while maintaining consistency within models and with theory and data. The project involved collaboration between researchers at Bucknell University, Boston University, University of mode Island, and the USDNARS Hydrology Laboratory. This report focuses on the work done at Bucknell, which used an analytical continuous-source flux model developed by Crago (1998), based on work by Brutsaert and Sugita (1996) to generate fluxes at all levels of the canopy. Named ALARM [Analytical Land- Atmosphere-Radiometer Model] by Suleiman and Crago (2002), the model assumes the foliage has an exponential vertical temperature profile. The same profile is felt by the within-canopy turbulence and 'seen" by a radiometer viewing the surface from any zenith view angle. ALARM converts radiometric surface temperatures taken from any view angle into a clearly-defined version of Taero called the equivalent isothermal surface temperature T(sub s,j), and then calculates the sensible heat flux H using Monin-Obukhov similarity theory. This allows remotely sensed Ts,r measurements to be used to produce high quality sensible and latent heat flux estimates, or to validate or update the surface temperature produced by SVATs in climate or mesoscale models.

  18. 16 CFR 1505.7 - Maximum acceptable surface temperatures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Maximum acceptable surface temperatures. 1505.7 Section 1505.7 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR ELECTRICALLY OPERATED TOYS OR OTHER ELECTRICALLY OPERATED ARTICLES INTENDED FOR USE BY CHILDREN Regulations...

  19. Surface and Atmospheric Contributions to Passive Microwave Brightness Temperatures

    NASA Technical Reports Server (NTRS)

    Jackson, Gail Skofronick; Johnson, Benjamin T.

    2010-01-01

    Physically-based passive microwave precipitation retrieval algorithms require a set of relationships between satellite observed brightness temperatures (TB) and the physical state of the underlying atmosphere and surface. These relationships are typically non-linear, such that inversions are ill-posed especially over variable land surfaces. In order to better understand these relationships, this work presents a theoretical analysis using brightness temperature weighting functions to quantify the percentage of the TB resulting from absorption/emission/reflection from the surface, absorption/emission/scattering by liquid and frozen hydrometeors in the cloud, the emission from atmospheric water vapor, and other contributors. The results are presented for frequencies from 10 to 874 GHz and for several individual precipitation profiles as well as for three cloud resolving model simulations of falling snow. As expected, low frequency channels (<89 GHz) respond to liquid hydrometeors and the surface, while the higher frequency channels become increasingly sensitive to ice hydrometeors and the water vapor sounding channels react to water vapor in the atmosphere. Low emissivity surfaces (water and snow-covered land) permit energy downwelling from clouds to be reflected at the surface thereby increasing the percentage of the TB resulting from the hydrometeors. The slant path at a 53deg viewing angle increases the hydrometeor contributions relative to nadir viewing channels and show sensitivity to surface polarization effects. The TB percentage information presented in this paper answers questions about the relative contributions to the brightness temperatures and provides a key piece of information required to develop and improve precipitation retrievals over land surfaces.

  20. Effect of microorganism on Greenland ice sheet surface temperature change

    NASA Astrophysics Data System (ADS)

    Shimada, R.; Takeuchi, N.; Aoki, T.

    2012-12-01

    Greenland ice sheet holds approximately 10% of the fresh water on earth. If it melts all, sea level rises about 7.2meter. It is reported that mass of Greenland ice sheet is decreasing with temperature rising of climate change. Melting of the coastal area is particularly noticeable. It is established that 4 to 23% of the sea level rising from 1993 to 2005 is caused by the melting of Greenland ice sheet. In 2010, amount of melting per year became the largest than the past. However many climate models aren't able to simulate the recent melting of snow and ice in the Arctic including Greenland. One of the possible causes is albedo reduction of snow and ice surface by light absorbing snow impurities such as black carbon and dust and by glacial microorganisms. But there are few researches for effect of glacial microorganism in wide area. So it is important to clarify the impact of glacial microorganisms in wide area. The purpose of this study is to clarify the effect of microorganism on Greenland ice sheet surface temperature change using satellite images of visible, near infrared and thermal infrared wavelength range and observation carried out in northwestern Greenland. We use MODIS Land Surface Temperature Product as ice sheet surface temperature. It estimates land surface temperature based on split window method using thermal infrared bands. MODIS data is bound to cover the whole of Greenland, and calculated the ratio of the temperature change per year. Analysis period is from December 2002 to November 2010. Results of calculating Greenland ice sheet surface temperature change using the MODIS data, our analysis shows that it is upward trend in the whole region. We find a striking upward trend in northern and western part of Greenland. The rate is 0.33±0.03 degree Celsius per a year from 47.5°W to 49°W. While in the coastal area from 49°W to 50.7°W, the rate is 0.26±0.06 degree Celsius per a year. This large upward trend area is the same area as dark region

  1. Combined effects of retinol, ascorbic acid and α-tocopherol on diurnal variations in rectal temperature of Black Harco pullets subjected to heat stress

    NASA Astrophysics Data System (ADS)

    Sinkalu, Victor Olusegun; Ayo, Joseph Olusegun

    2016-06-01

    The experiment was performed with the aim of determining the effect of co-administration of antioxidant vitamins, retinol, ascorbic acid and α-tocopherol on rectal temperature (RT) fluctuations in pullets during the hot-dry season in Nigeria. Forty-eight Black Harco pullets, aged 16 weeks and weighing 1.5 ± 0.03 kg were divided by simple random sampling into two groups, consisting of 28 treated and 20 control Black Harco pullets. The RTs of 28 treated and 20 control Black Harco pullets were measured hourly for 3 days, 3 days apart, from 06:00 to 19:00 h (GMT + 1) with a standard clinical thermometer. The treated pullets were administered individually with the vitamins orally in water, while the control pullets were given only water. The lowest hourly RT of 40.9 ± 0.04 °C was obtained in treated pullets at 06:00 h, while the highest value of 41.1 ± 0.01 °C was recorded from 17:00 to 19:00 h (P < 0.001). In control pullets, the RT rose significantly from 41.0 ± 0.03 °C at 06:00 h to the maximum value of 41.6 ± 0.04 °C at 15:00 h (P < 0.001). The pullets co-administered with retinol, ascorbic acid and α-tocopherol had consistently lower RT values than those of control pullets, especially during the hot hours of the day, from 13:00 to 17:00 h. It is concluded that co-administration of retinol, ascorbic acid and α-tocopherol, by preventing a rise in body temperature, ameliorated heat stress, and may enhance productivity of pullets reared under unfavourable, thermal environment conditions.

  2. Land Surface Temperature- Comparing Data from Polar Orbiting and Geostationary Satellites

    NASA Astrophysics Data System (ADS)

    Comyn-Platt, E.; Remedios, J. J.; Good, E. J.; Ghent, D.; Saunders, R.

    2012-04-01

    Land Surface Temperature (LST) is a vital parameter in Earth climate science, driving long-wave radiation exchanges that control the surface energy budget and carbon fluxes, which are important factors in Numerical Weather Prediction (NWP) and the monitoring of climate change. Satellites offer a convenient way to observe LST consistently and regularly over large areas. A comparison between LST retrieved from a Geostationary Instrument, the Spinning Enhanced Visible and InfraRed Imager (SEVIRI), and a Polar Orbiting Instrument, the Advanced Along Track Scanning Radiometer (AATSR) is presented. Both sensors offer differing benefits. AATSR offers superior precision and spatial resolution with global coverage but given its sun-synchronous platform only observes at two local times, ~10am and ~10pm. SEVIRI provides the high-temporal resolution (every 15 minutes) required for observing diurnal variability of surface temperatures but given its geostationary platform has a poorer resolution, 3km at nadir, which declines at higher latitudes. A number of retrieval methods are applied to the raw satellite data: First order coefficient based algorithms provided on an operational basis by the LandSAF (for SEVIRI) and the University of Leicester (for AATSR); Second order coefficient based algorithms put forward by the University of Valencia; and an optimal estimation method using the 1DVar software provided by the NWP SAF. Optimal estimation is an iterative technique based upon inverse theory, thus is very useful for expanding into data assimilation systems. The retrievals are assessed and compared on both a fine scale using in-situ data from recognised validation sites and on a broad scale using two 100x100 regions such that biases can be better understood. Overall, the importance of LST lies in monitoring daily temperature extremes, e.g. for estimating permafrost thawing depth or risk of crop damage due to frost, hence the ideal dataset would use a combination of observations

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

    PubMed

    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

  4. Modeling Apple Surface Temperature Dynamics Based on Weather Data

    PubMed Central

    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

  5. Temperature maps measurements on 3D surfaces with infrared thermography

    NASA Astrophysics Data System (ADS)

    Cardone, Gennaro; Ianiro, Andrea; Dello Ioio, Gennaro; Passaro, Andrea

    2012-02-01

    The use of the infrared camera as a temperature transducer in wind tunnel applications is convenient and widespread. Nevertheless, the infrared data are available in the form of 2D images while the observed surfaces are often not planar and the reconstruction of temperature maps over them is a critical task. In this work, after recalling the principles of IR thermography, a methodology to rebuild temperature maps on the surfaces of 3D object is proposed. In particular, an optical calibration is applied to the IR camera by means of a novel target plate with control points. The proposed procedure takes also into account the directional emissivity by estimating the viewing angle. All the needed steps are described and analyzed. The advantages given by the proposed method are shown with an experiment in a hypersonic wind tunnel.

  6. Plasma temperature rise toward the plasma-facing surface

    NASA Astrophysics Data System (ADS)

    Nishijima, D.; Doerner, R. P.; Seraydarian, R. P.; De Temmerman, G.; van der Meiden, H. J.

    2015-08-01

    Detailed measurements of axial electron temperature, Te, profiles in the presheath region were carried out using a Langmuir probe and the line intensity ratio technique for both He I (728.1 nm/706.5 nm) and Be II (467.3 nm/313.1 nm). The results show that Te increases toward the material surface, which contradicts the standard picture that Te is constant along the magnetic field in the sheath-limited regime. While no target bias voltage, Vb, dependence is seen, the Te rise becomes more prominent with decreasing neutral pressure. Similarly, the ion temperature, Ti, evaluated from Doppler broadening of a He II line emission at 468.6 nm is found to increase toward the surface, but also does not depend on Vb. Possible mechanisms of the Te and Ti rise as well as validity of the line intensity ratio technique near the material surface are discussed.

  7. A Titan atmosphere with a surface temperature of 200K

    NASA Technical Reports Server (NTRS)

    Hunten, D. M.

    1978-01-01

    The brightness temperature of Titan at 3 mm wavelength is around 200 K according to Ulich, Conklin, and Dickel (1978). Although an earlier measurement by Briggs is much colder, 200 K as the surface temperature was used to build an atmospheric model with a surface pressure of 21 bars. CH4 clouds form between 100 and 120 km altitude. The visual limb is near 200 km. The methane mixing ratio is 0.25 percent above the clouds and 7 percent below; the dominant gas is assumed to be N2. The thermal opacity is due to pressure-induced absorption in N2 and a trace (0.5 percent) of H2, with some help from cloud particles; unit opacity is reached at 600 mbar, 110 km from the surface. The radius of the solid body in this model is 2700 km, in reasonable agreement with 2600 km obtained if the density is the same as that of Ganymede and Callisto.

  8. Finite element simulation of temperature dependent free surface flows

    NASA Technical Reports Server (NTRS)

    Engelman, M. S.; Sani, R. L.

    1985-01-01

    The method of Engelman and Sani (1984) for a finite-element simulation of incompressible surface flows with a free and/or moving fluid interface, such as encountered in crystal growth and coating and polymer technology, is extended to temperature-dependent flows, including the effect of temperature-dependent surface tension. The basic algorithm of Saito and Scriven (1981) and Ruschak (1980) has been generalized and implemented in a robust and versatile finite-element code that can be employed with relative ease for the simulation of free-surface problems in complex geometries. As a result, the costly dependence on the Newton-Raphson algorithm has been eliminated by replacing it with a quasi-Newton iterative method, which nearly retains the superior convergence properties of the Newton-Raphson method.

  9. Linking geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    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.

  10. Changes in net ecosystem productivity of boreal black spruce stands in response to changes in temperature at diurnal and seasonal time scales.

    PubMed

    Grant, R F; Margolis, H A; Barr, A G; Black, T A; Dunn, A L; Bernier, P Y; Bergeron, O

    2009-01-01

    Net ecosystem productivity (NEP) of boreal coniferous forests is believed to rise with climate warming, thereby offsetting some of the rise in atmospheric CO(2) concentration (C(a)) by which warming is caused. However, the response of conifer NEP to warming may vary seasonally, with rises in spring and declines in summer. To gain more insight into this response, we compared changes in CO(2) exchange measured by eddy covariance and simulated by the ecosystem process model ecosys under rising mean annual air temperatures (T(a)) during 2004-2006 at black spruce stands in Saskatchewan, Manitoba and Quebec. Hourly net CO(2) uptake was found to rise with warming at T(a) < 15 degrees C and to decline with warming at T(a) > 20 degrees C. As mean annual T(a) rose from 2004 to 2006, increases in net CO(2) uptake with warming at lower T(a) were greater than declines with warming at higher T(a) so that annual gross primary productivity and hence NEP increased. Increases in net CO(2) uptake measured at lower T(a) were explained in the model by earlier recovery of photosynthetic capacity in spring, and by increases in carboxylation activity, using parameters for the Arrhenius temperature functions of key carboxylation processes derived from independent experiments. Declines in net CO(2) uptake measured at higher T(a) were explained in the model by sharp declines in mid-afternoon canopy stomatal conductance (g(c)) under higher vapor pressure deficits (D). These declines were modeled from a hydraulic constraint to water uptake imposed by low axial conductivity of conifer roots and boles that forced declines in canopy water potential (psi(c)), and hence in g(c) under higher D when equilibrating water uptake with transpiration. In a model sensitivity study, the contrasting responses of net CO(2) uptake to specified rises in T(a) caused annual NEP of black spruce in the model to rise with increases in T(a) of up to 6 degrees C, but to decline with further increases at mid

  11. Plateau effects on diurnal circulation patterns

    SciTech Connect

    Reiter, E.R.; Tang, M.

    1984-04-01

    The diurnal variation of 850 mb heights, the detailed distribution of which could be assessed by the inclusion of surface data, and of resultant winds over, and in the vicinity of, the Great Basin reveals clearly a plateau-wind circulation during summer. This circulation reverses between day and night and appears to include the low-level jet stream over Texas and Oklahoma, as well as the time of occurrence of thunderstorms. This plateau circulation system interacts with local mountain-valley breeze systems. The thickness of the daytime inflow and nighttime outflow layer over the plateau is approximately 2 km. 19 references, 11 figures, 1 table.

  12. Diurnal emissivity dynamics in bare versus biocrusted sand dunes.

    PubMed

    Rozenstein, Offer; Agam, Nurit; Serio, Carmine; Masiello, Guido; Venafra, Sara; Achal, Stephen; Puckrin, Eldon; Karnieli, Arnon

    2015-02-15

    Land surface emissivity (LSE) in the thermal infrared depends mainly on the ground cover and on changes in soil moisture. The LSE is a critical variable that affects the prediction accuracy of geophysical models requiring land surface temperature as an input, highlighting the need for an accurate derivation of LSE. The primary aim of this study was to test the hypothesis that diurnal changes in emissivity, as detected from space, are larger for areas mostly covered by biocrusts (composed mainly of cyanobacteria) than for bare sand areas. The LSE dynamics were monitored from geostationary orbit by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) over a sand dune field in a coastal desert region extending across both sides of the Israel-Egypt political borderline. Different land-use practices by the two countries have resulted in exposed, active sand dunes on the Egyptian side (Sinai), and dunes stabilized by biocrusts on the Israeli side (Negev). Since biocrusts adsorb more moisture from the atmosphere than bare sand does, and LSE is affected by the soil moisture, diurnal fluctuations in LSE were larger for the crusted dunes in the 8.7 μm channel. This phenomenon is attributed to water vapor adsorption by the sand/biocrust particles. The results indicate that LSE is sensitive to minor changes in soil water content caused by water vapor adsorption and can, therefore, serve as a tool for quantifying this effect, which has a large spatial impact. As biocrusts cover vast regions in deserts worldwide, this discovery has repercussions for LSE estimations in deserts around the globe, and these LSE variations can potentially have considerable effects on geophysical models from local to regional scales. PMID:25437760

  13. Diurnal emissivity dynamics in bare versus biocrusted sand dunes

    NASA Astrophysics Data System (ADS)

    Rozenstein, O.

    2015-12-01

    Land surface emissivity (LSE) in the thermal infrared depends mainly on the ground cover and on changes in soil moisture. The LSE is a critical variable that affects the prediction accuracy of geophysical models requiring land surface temperature as an input, highlighting the need for an accurate derivation of LSE. The primary aim of this study was to test the hypothesis that diurnal changes in emissivity, as detected from space, are larger for areas mostly covered by biocrusts (composed mainly of cyanobacteria) than for bare sand areas. The LSE dynamics were monitored from geostationary orbit by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) over a sand dune field in a coastal desert region extending across both sides of the Israel-Egypt political borderline. Different land-use practices by the two countries have resulted in exposed, active sand dunes on the Egyptian side (Sinai), and dunes stabilized by biocrusts on the Israeli side (Negev). Since biocrusts adsorb more moisture from the atmosphere than bare sand does, and LSE is affected by the soil moisture, diurnal fluctuations in LSE were larger for the crusted dunes in the 8.7 μm channel. This phenomenon is attributed to water vapor adsorption by the sand / biocrust particles. The results indicate that LSE is sensitive to minor changes in soil water content caused by water vapor adsorption and can, therefore, serve as a tool for quantifying this effect, which has a large spatial impact. As biocrusts cover vast regions in deserts worldwide, this discovery has repercussions for LSE estimations in deserts around the globe, and these LSE variations can potentially have considerable effects on geophysical models from local to regional scales.

  14. Study of bacterial adhesion on biomimetic temperature responsive glycopolymer surfaces.

    PubMed

    Wang, Yinan; Kotsuchibashi, Yohei; Liu, Yang; Narain, Ravin

    2015-01-28

    Pseudomonas aeruginosa is an opportunistic pathogen responsible for diseases such as bacteremia, chronic lung infection, and acute ulcerative keratitis. P. aeruginosa induced diseases can be fatal as the exotoxins and endotoxins released by the bacterium continue to damage host tissues even after the administration of antibiotics. As bacterial adhesion on cell surfaces is the first step in bacterial based pathogen infections, the control of bacteria-cell interactions is a worthwhile research target. In this work, thermally responsive poly(N-isopropylacrylamide) [P(NIPAAm)] based biomimetic surfaces were developed to study the two major bacterial infection mechanisms, which is believed to be mediated by hydrophobic or lectin-carbohydrate interactions, using quartz crystal microbalance with dissipation. Although, a greater number of P. aeruginosa adhered to the NIPAAm homopolymer modified surfaces at temperatures higher than the lower critical solution temperature (LCST), the bacterium-substratum bond stiffness was stronger between P. aeruginosa and a galactose based P(NIPAAm) surface. The high bacterial adhesion bond stiffness observed on the galactose based thermally responsive surface at 37 °C might suggest that both hydrophobic and lectin-carbohydrate interactions contribute to bacterial adhesion on cell surfaces. Our investigation also suggests that the lectin-carbohydrate interaction play a significant role in bacterial infections. PMID:25548940

  15. Thoracic surface temperature rhythms as circadian biomarkers for cancer chronotherapy

    PubMed Central

    Roche, Véronique Pasquale; Mohamad-Djafari, Ali; Innominato, Pasquale Fabio; Karaboué, Abdoulaye; Gorbach, Alexander; Lévi, Francis Albert

    2014-01-01

    The disruption of the temperature circadian rhythm has been associated with cancer progression, while its amplification resulted in cancer inhibition in experimental tumor models. The current study investigated the relevance of skin surface temperature rhythms as biomarkers of the Circadian Timing System (CTS) in order to optimize chronotherapy timing in individual cancer patients. Baseline skin surface temperature at four sites and wrist accelerations were measured every minute for 4 days in 16 patients with metastatic gastro-intestinal cancer before chronotherapy administration. Temperature and rest-activity were recorded, respectively, with wireless skin surface temperature patches (Respironics, Phillips) and an actigraph (Ambulatory Monitoring). Both variables were further monitored in 10 of these patients during and after a 4-day course of a fixed chronotherapy protocol. Collected at baseline, during and after therapy longitudinal data sets were processed using Fast Fourier Transform Cosinor and Linear Discriminant Analyses methods. A circadian rhythm was statistically validated with a period of 24 h (p<0.05) for 49/61 temperature time series (80.3%), and 15/16 rest-activity patterns (93.7%) at baseline. However, individual circadian amplitudes varied from 0.04 °C to 2.86 °C for skin surface temperature (median, 0.72 °C), and from 16.6 to 146.1 acc/min for rest-activity (median, 88.9 acc/min). Thirty-nine pairs of baseline temperature and rest-activity time series (75%) were correlated (r>|0.7|; p<0.05). Individual circadian acrophases at baseline were scattered from 15:18 to 6:05 for skin surface temperature, and from 12:19 to 15:18 for rest-activity, with respective median values of 01:10 (25–75% quartiles, 22:35–3:07) and 14:12 (13:14–14:31). The circadian patterns in skin surface temperature and rest-activity persisted or were amplified during and after fixed chronotherapy delivery for 5/10 patients. In contrast, transient or sustained disruption

  16. Lithological and textural controls on radar and diurnal thermal signatures of weathered volcanic deposits, Lunar Crater region, Nevada

    NASA Technical Reports Server (NTRS)

    Plaut, Jeffrey J.; Rivard, Benoit

    1992-01-01

    Radar backscatter intensity as measured by calibrated synthetic aperture radar (SAR) systems is primarily controlled by three factors: local incidence angle, wavelength-scale roughness, and dielectric permittivity of surface materials. Radar observations may be of limited use for geological investigations of surface composition, unless the relationships between lithology and the above characteristics can be adequately understood. In arid terrains, such as the Southwest U.S., weathering signatures (e.g. soil development, fracturing, debris grain size and shape, and hill slope characteristics) are controlled to some extent by lithologic characteristics of the parent bedrock. These textural features of outcrops and their associated debris will affect radar backscatter to varying degrees, and the multiple-wavelength capability of the JPL Airborne SAR (AIRSAR) system allows sampling of textures at three distinct scales. Diurnal temperature excursions of geologic surfaces are controlled primarily by the thermal inertia of surface materials, which is a measure of the resistance of a material to a change in temperature. Other influences include albedo, surface slopes affecting insolation, local meteorological conditions and surface emissivity at the relevant thermal wavelengths. To first order, thermal inertia variations on arid terrain surfaces result from grain size distribution and porosity differences, at scales ranging from micrometers to tens of meters. Diurnal thermal emission observations, such as those made by the JPL Thermal Infrared Multispectral Scanner (TIMS) airborne instrument, are thus influenced by geometric surface characteristics at scales comparable to those controlling radar backscatter. A preliminary report on a project involving a combination of field, laboratory and remote sensing observations of weathered felsic-to basaltic volcanic rock units exposed in the southern part of the Lunar Crater Volcanic Field, in the Pancake Range of central Nevada is

  17. Effect of ambient temperature and attachment method on surface temperature measurements

    NASA Astrophysics Data System (ADS)

    Psikuta, Agnes; Niedermann, Reto; Rossi, René M.

    2014-07-01

    Accurate measurement of skin surface temperature is essential in both thermo-physiological and clinical applications. However, a literature review of the last two decades of physiological or clinical research revealed an inconsistency or a lack of information on how temperature sensors were attached to the skin surface. The purpose of this study was to systematically compare and quantify the performance of different commercially available temperature sensors and their typical attachment methods, and, secondly, to provide a time-efficient and reliable method for testing any sensor-tape combination. In conclusion, both the sensor type and the attachment method influenced the results of temperature measurements (both its absolute and relative dimensions). The sensor shape and the contact of its sensing area to the surface, as well as the conductance of the tape were the most important parameters to minimise the influence of environmental conditions on surface temperature measurement. These results suggest that temperature sensors and attachment methods for human subject and manikin trials should be selected carefully, with a systematic evaluation of the sensor-tape system under conditions of use, and emphasise the need to report these parameters in publications.

  18. [Prediction of high temperature harm to rice in Jiangsu Province based on sea surface temperature].

    PubMed

    Pan, Ao-Da; Gao, Ping; Liu, Mei; Wang, Chun-Yi

    2010-01-01

    Based on the measurements of rice growth and the ordinary meteorological observations from eight main agro-meteorological stations in Jiangsu Province in 1986-2007, this paper analyzed the characteristics of generation circulation corresponding to the abnormal strong and southern subtropical high pressure in 2003 (the year with a typically high temperature), the relationships between the abnormalities of subtropical high pressure and previous sea surface temperature, and the physiological responses of rice to the abnormal high temperature during its crucial development stages. In the meantime, a field correlation analysis was made on the relationships between the harm index of high temperature in the northern (Huaibei), middle (Jianghuai), and southern (Sunan) areas of Jiangsu and the sea surface temperature (SST) of Western Pacific. The results showed that the harm index of high temperature in the three areas was highly correlated with the SST of Nino area, northern area, and warm pool area of Western Pacific, respectively, but the significance and temporal evolution of the correlations varied among the areas. The transformation of SST was conducted to optimize its correlation with the harm index of high temperature, and an increased reliability of SST acting as a predictor of high temperature harm was obtained. The simulation results of the established models in predicting high temperature harm to rice in Huaibei, Jianghuai and Sunan areas of Jiangsu Province were significant at 0.01 level. PMID:20387435

  19. Spatiotemporal temperature profiling of corneal surface during LTK

    NASA Astrophysics Data System (ADS)

    Papaioannou, Thanassis; Maguen, Ezra I.; Grundfest, Warren S.

    2002-06-01

    Accurate prediction of LTK treatments requires refined thermal corneal models which necessitate precise input parameters. The overall objective of this study was to provide detailed information on the spatiotemporal temperature profile of the corneal surface, during in-vitro thermal keratoplasty. LTK was performed in-vitro on freshly harvested porcine eyes (N equals 16) with the Sunrise Technologies corneal shaping system (Model SUN 1000). Spatiotemporal thermal imaging of the irradiated corneas were obtained with a short wave Inframetrics thermal camera (Model PM290). Images were obtained at 8-bits resolution, with ~100 microns spatial and ~17 msec temporal resolution respectively. Treatment pattern consisted of eight spots at 6 mm zone, while lasing was conducted at settings of either 100 mJ and 15 pulses (N equals 8), or 260 mJ and 7 pulses (N equals 8). Temporal and spatial variation of the corneal surface temperatures were calculated at locations of importance to LTK. At the laser spot, temperature profiles consisted of transients coinciding approximately with the laser pulses. Maximum transient temperatures observed were 98.0+/- 4.6 degree(s)C for the high and 56.3+/- 2.6 degree(s)C for the low energy respectively. These temperature transients were superimposed on an envelope of lower-slowly varying temperatures. The maximum temperatures observed for this temperature envelope, were 51.8+/- 3.4 degree(s)C for the high and 35.4+/- 3.4 degree(s)C for the low energy respectively. The evolution of either the maximum temperature transients or the lower temperature envelope, followed exponential growth of the form: T equals A * exp(B*t). Maximum temperatures at locations 0.5 mm and 1 mm away from the laser spot, reached 25.7 degree(s)C and 23.3 degree(s)C for the low energy, and 34 degree(s)C and 25.6 degree(s)C for the high energy settings respectively. Temperature decay constants were approximately 2 to 3 sec, while the spatial temperature profile at the laser

  20. Surface activation-based nanobonding and interconnection at room temperature

    NASA Astrophysics Data System (ADS)

    Howlader, M. M. R.; Yamauchi, A.; Suga, T.

    2011-02-01

    Flip chip nanobonding and interconnect system (NBIS) equipment with high precision alignment has been developed based on the surface activated bonding method for high-density interconnection and MEMS packaging. The 3σ alignment accuracy in the IR transmission system was approximately ±0.2 µm. The performance of the NBIS has been preliminarily investigated through bonding between relatively rough surfaces of copper through silicon vias (Cu-TSVs) and gold-stud bumps (Au-SBs), and smooth surfaces of silicon wafers. The Cu-TSVs of 55 µm diameter and the Au-SBs of 35 µm diameter with ~6-10 nm surface roughness (RMS) were bonded at room temperature after surface activation using an argon fast atom beam (Ar-FAB) under 0.16 N per bump. Silicon wafers of 50 mm diameter with ~0.2 nm RMS surface roughness were bonded without heating after surface activation. Void-free interfaces both in Cu-TSV/Au-SB and silicon/silicon with bonding strength equivalent to bulk fracture of Au and silicon, respectively, were achieved. A few nm thick amorphous layers were observed across the silicon/silicon interface that was fabricated by the Ar-FAB. This study in the interconnection and bonding facilitates the required three-dimensional integration on the same surface for high-density electronic and biomedical systems.

  1. Influences of twilight on diurnal variation of core temperature, its nadir, and urinary 6-hydroxymelatonin sulfate during nocturnal sleep and morning drowsiness.

    PubMed

    Kondo, Masayuki; Tokura, Hiromi; Wakamura, Tomoko; Hyun, Ki-Ja; Tamotsu, Satoshi; Morita, Takeshi; Oishi, Tadashi

    2009-03-01

    This study aimed at elucidating the physiological significance of dusk and dawn in the circadian rhythm of core temperature (T(core)) and urinary 6-hydroxymelatonin sulfate in humans during sleep and the waking sensation just after rising. Seven female and four male students served as participants. Participants retired at 2300 h and rose at 0700 h. They were requested to sit on a chair and spend time as quietly as possible during wakefulness, reading a book or listening to recorded light music. Two lighting conditions were provided for each participant: 1) Light-Dark (LD)-rectangular light change with abrupt decrease from 3,000 lx to 100 lx at 1800 h, abrupt increase from 0 lx to 3,000 lx at 0700 h. 2) LD-twilight light change with gradual decrease from 3,000 lx to 100 lx starting at 1700 h (twilight period about 2 h), with gradual increase from 0 lx to 3,000 lx starting at 0500 h (twilight period about 2 h). The periods of 0 lx at night were from 2300 h to 0700 h on the first day and from 2300 to 0500 h on the second day. Nadir time advanced significantly under the influence of the LD-twilight condition. The amount of 6-hydroxymelatonin sulfate in urine collected at 0200 h was significantly higher under LD-twilight in comparison with LD-rectangular light. Morning drowsiness tended to be lower under LD-twilight. Our results suggest that in architectural design of indoor illumination it is important to provide LD-twilight in the evening and early morning for sleep promotion in healthy normal people and/or light treatment in elderly patients with advanced dementia. PMID:19408625

  2. Improved accuracy of the remote sensing of sea surface temperature

    NASA Technical Reports Server (NTRS)

    Dalu, G.; Prabhakara, C.; Lo, R. C.

    1981-01-01

    A method is described for determining the water vapor content to within + or - 0.4 g/sq cm from remotely sensed radiances in three infrared channels, 11, 13, 18 microns. Using this method, it is possible to significantly improve the accuracy of sea surface temperature (SST) over what is obtainable with the two channel technique. A radiative computational scheme for the radiative transfer equation is used to study the manner in which the equivalent radiative temperature of the atmosphere changes as a function of wave number for different atmospheric conditions. Average climatological conditions are used to simulate the radiative response of the atmosphere. This radiative transfer simulation is used to compute brightness temperatures for radiosonde profiles obtained from oceanographic ships, which temperatures are in turn used to estimate the SST. Nimbus 4 IRIS spectral measurements corresponding to the profiles were used in the same way for purposes of comparison.

  3. Perturbation of ground surface temperature reconstructions by groundwater flow?

    NASA Astrophysics Data System (ADS)

    Ferguson, Grant; Beltrami, Hugo; Woodbury, Allan D.

    2006-07-01

    Subsurface temperatures have been shown to be a robust source of information on past climates. Most analyses neglect groundwater flow (GWF) and assume purely conductive heat flow. However, in many situations GWF has not been fully considered and to date there are no general GWF criteria for either accepting or rejecting a temperature profile for paleoclimate analysis. Here we examine the transition from conduction dominated environments to environments where advection has a significant effect on the subsurface temperature regime and thus ground surface temperature (GST) histories. We provide guidelines indicating when advection is important and conclude that it is unlikely that groundwater flow is a significant source of error in the global data set maintained by the International Heat Flow Commission.

  4. Designing high-temperature steels via surface science and thermodynamics

    NASA Astrophysics Data System (ADS)

    Gross, Cameron T.; Jiang, Zilin; Mathai, Allan; Chung, Yip-Wah

    2016-06-01

    Electricity in many countries such as the US and China is produced by burning fossil fuels in steam-turbine-driven power plants. The efficiency of these power plants can be improved by increasing the operating temperature of the steam generator. In this work, we adopted a combined surface science and computational thermodynamics approach to the design of high-temperature, corrosion-resistant steels for this application. The result is a low-carbon ferritic steel with nanosized transition metal monocarbide precipitates that are thermally stable, as verified by atom probe tomography. High-temperature Vickers hardness measurements demonstrated that these steels maintain their strength for extended periods at 700 °C. We hypothesize that the improved strength of these steels is derived from the semi-coherent interfaces of these thermally stable, nanosized precipitates exerting drag forces on impinging dislocations, thus maintaining strength at elevated temperatures.

  5. Evidence of Lunar Phase Influence on Global Surface Air Temperatures

    NASA Technical Reports Server (NTRS)

    Anyamba, Ebby; Susskind, Joel

    2000-01-01

    Intraseasonal oscillations appearing in a newly available 20-year record of satellite-derived surface air temperature are composited with respect to the lunar phase. Polar regions exhibit strong lunar phase modulation with higher temperatures occurs near full moon and lower temperatures at new moon, in agreement with previous studies. The polar response to the apparent lunar forcing is shown to be most robust in the winter months when solar influence is minimum. In addition, the response appears to be influenced by ENSO events. The highest mean temperature range between full moon and new moon in the polar region between 60 deg and 90 deg latitude was recorded in 1983, 1986/87, and 1990/91. Although the largest lunar phase signal is in the polar regions, there is a tendency for meridional equatorward progression of anomalies in both hemispheres so that the warning in the tropics occurs at the time of the new moon.

  6. H2O Adsorption on Smectites: Application to the Diurnal Variation of H2O in the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Zent, Aaron P.; Howard, J.; Quinn, R. C.

    2000-01-01

    Observations of the Martian planetary boundary layer lead to interpretations that are baffling and contradictory. In this paper, we specifically address the question of whether or not water vapor finds a substantial diurnal reservoir in the Martian regolith. To address this issue, we have measured H2O adsorption kinetics on SWy-1, a Na-rich montmorillonite from Wyoming. The highest-temperature (273 K) data equilibrates rapidly. Data gathered at realistic H2O partial pressures and temperatures appropriate to early morning show two phenomena that preclude a significant role for smectites in diurnally exchanging a large column abundance. First, the equilibration timescale is longer than a sol. Second, the equilibrium abundances are a small fraction of that predicted by earlier adsorption isotherms. The explanation for this phenomenon is that smectite clay actually increases its surface area as a function of adsorptive coverage. At Mars-like conditions, we show that the interlayer sites of smectites are likely to be unavailable.

  7. Innovative approach to retrieve land surface emissivity and land surface temperature in areas of highly dynamic emissivity changes by using thermal infrared data

    NASA Astrophysics Data System (ADS)

    Heinemann, S.

    2015-12-01

    The land surface temperature (LST) is an extremely significant parameter in order to understand the processes of energetic interactions between Earth's surface and atmosphere. This knowledge is significant for various environmental research questions, particularly with regard to the recent climate change. This study shows an innovative approach to retrieve land surface emissivity (LSE) and LST by using thermal infrared (TIR) data from satellite sensors, such as SEVIRI and AATSR. So far there are no methods to derive LSE/LST particularly in areas of highly dynamic emissivity changes. Therefore especially for regions with large surface temperature amplitude in the diurnal cycle such as bare and uneven soil surfaces but also for regions with seasonal changes in vegetation cover including various surface areas such as grassland, mixed forests or agricultural land different methods were investigated to identify the most appropriate one. The LSE is retrieved by using the day/night Temperature-Independent Spectral Indices (TISI) method, and the Generalised Split-Window (GSW) method is used to retrieve the LST. Nevertheless different GSW algorithms show that equal LSEs lead to large LST differences. Additionally LSE is also measured using a NDVI-based threshold method (NDVITHM) to distinguish between soil, dense vegetation cover and pixel composed of soil and vegetation. The data used for this analysis were derived from MODIS TIR. The analysis is implemented with IDL and an intercomparison is performed to determine the most effective methods. To compensate temperature differences between derived and ground truth data appropriate correction terms by comparing derived LSE/LST data with ground-based measurements are developed. One way to calibrate LST retrievals is by comparing the canopy leaf temperature of conifers derived from TIR data with the surrounding air temperature (e.g. from synoptic stations). Prospectively, the derived LSE/LST data become validated with near

  8. Impervious surfaces and sewer pipe effects on stormwater runoff temperature

    NASA Astrophysics Data System (ADS)

    Sabouri, F.; Gharabaghi, B.; Mahboubi, A. A.; McBean, E. A.

    2013-10-01

    The warming effect of the impervious surfaces in urban catchment areas and the cooling effect of underground storm sewer pipes on stormwater runoff temperature are assessed. Four urban residential catchment areas in the Cities of Guelph and Kitchener, Ontario, Canada were evaluated using a combination of runoff monitoring and modelling. The stormwater level and water temperature were monitored at 10 min interval at the inlet of the stormwater management ponds for three summers 2009, 2010 and 2011. The warming effect of the ponds is also studied, however discussed in detail in a separate paper. An artificial neural network (ANN) model for stormwater temperature was trained and validated using monitoring data. Stormwater runoff temperature was most sensitive to event mean temperature of the rainfall (EMTR) with a normalized sensitivity coefficient (Sn) of 1.257. Subsequent levels of sensitivity corresponded to the longest sewer pipe length (LPL), maximum rainfall intensity (MI), percent impervious cover (IMP), rainfall depth (R), initial asphalt temperature (AspT), pipe network density (PND), and rainfall duration (D), respectively. Percent impervious cover of the catchment area (IMP) was the key parameter that represented the warming effect of the paved surfaces; sensitivity analysis showed IMP increase from 20% to 50% resulted in runoff temperature increase by 3 °C. The longest storm sewer pipe length (LPL) and the storm sewer pipe network density (PND) are the two key parameters that control the cooling effect of the underground sewer system; sensitivity analysis showed LPL increase from 345 to 966 m, resulted in runoff temperature drop by 2.5 °C.

  9. Surface emissivity and temperature retrieval for a hyperspectral sensor

    SciTech Connect

    Borel, C.C.

    1998-12-01

    With the growing use of hyper-spectral imagers, e.g., AVIRIS in the visible and short-wave infrared there is hope of using such instruments in the mid-wave and thermal IR (TIR) some day. The author believes that this will enable him to get around using the present temperature-emissivity separation algorithms using methods which take advantage of the many channels available in hyper-spectral imagers. A simple fact used in coming up with a novel algorithm is that a typical surface emissivity spectrum are rather smooth compared to spectral features introduced by the atmosphere. Thus, a iterative solution technique can be devised which retrieves emissivity spectra based on spectral smoothness. To make the emissivities realistic, atmospheric parameters are varied using approximations, look-up tables derived from a radiative transfer code and spectral libraries. One such iterative algorithm solves the radiative transfer equation for the radiance at the sensor for the unknown emissivity and uses the blackbody temperature computed in an atmospheric window to get a guess for the unknown surface temperature. By varying the surface temperature over a small range a series of emissivity spectra are calculated. The one with the smoothest characteristic is chosen. The algorithm was tested on synthetic data using MODTRAN and the Salisbury emissivity database.

  10. Urban pavement surface temperature. Comparison of numerical and statistical approach

    NASA Astrophysics Data System (ADS)

    Marchetti, Mario; Khalifa, Abderrahmen; Bues, Michel; Bouilloud, Ludovic; Martin, Eric; Chancibaut, Katia

    2015-04-01

    The forecast of pavement surface temperature is very specific in the context of urban winter maintenance. to manage snow plowing and salting of roads. Such forecast mainly relies on numerical models based on a description of the energy balance between the atmosphere, the buildings and the pavement, with a canyon configuration. Nevertheless, there is a specific need in the physical description and the numerical implementation of the traffic in the energy flux balance. This traffic was originally considered as a constant. Many changes were performed in a numerical model to describe as accurately as possible the traffic effects on this urban energy balance, such as tires friction, pavement-air exchange coefficient, and infrared flux neat balance. Some experiments based on infrared thermography and radiometry were then conducted to quantify the effect fo traffic on urban pavement surface. Based on meteorological data, corresponding pavement temperature forecast were calculated and were compared with fiels measurements. Results indicated a good agreement between the forecast from the numerical model based on this energy balance approach. A complementary forecast approach based on principal component analysis (PCA) and partial least-square regression (PLS) was also developed, with data from thermal mapping usng infrared radiometry. The forecast of pavement surface temperature with air temperature was obtained in the specific case of urban configurtation, and considering traffic into measurements used for the statistical analysis. A comparison between results from the numerical model based on energy balance, and PCA/PLS was then conducted, indicating the advantages and limits of each approach.

  11. Sea surface and remotely sensed temperatures off Cape Mendocino, California

    NASA Technical Reports Server (NTRS)

    Breaker, L. C.; Arvesen, J. C.; Frydenlund, D.; Myers, J. S.; Short, K.

    1985-01-01

    During September 3 to 5, 1979, a multisensor oceanographic experiment was conducted off Cape Mendocino, California. The purpose of this experiment was to validate the use of remote sensing techniques over an area along the U.S. west coast where coasted upwelling is known to be intense. Remotely sensed mutlispectral data, including thermal infrared imagery, were collected above an upwelling feature off Cape Mendocino. Data were acquired from the TIRNOS-N and NOAA-6 polar orbiting satellites, the NASA Ames Research Center's high altitude U-2 aircraft, and a U.S. Coast Guard C-130 aircraft. Supporting surface truth data over the same feature were collected aboard the National Oceanic and Atmospheric Administration (NOAA) ship, OCEANOGRAPHER. Atmospheric soundings were also taken aboard the ship. The results indicate that shipboard measurements of sea surface temperatures can be reproduction within 1 C or better through remote observation of absolute infrared radiance values (whether measured aboard the NOAA polar orbiting satellite, the U-2 aircraft, or the Coast Guard aircraft) by using appropriate atmospheric corrections. Also, the patterns of sea surface temperature which were derived independently from the various remote platforms provide a consistent interpretation of the surface temperature field.

  12. Ultraviolet surface plasmon-mediated low temperature hydrazine decomposition

    SciTech Connect

    Peng, Siying; Sheldon, Matthew T.; Atwater, Harry A.; Liu, Wei-Guang; Jaramillo-Botero, Andres; Goddard, William Andrew

    2015-01-12

    Conventional methods require elevated temperatures in order to dissociate high-energy nitrogen bonds in precursor molecules such as ammonia or hydrazine used for nitride film growth. We report enhanced photodissociation of surface-absorbed hydrazine (N{sub 2}H{sub 4}) molecules at low temperature by using ultraviolet surface plasmons to concentrate the exciting radiation. Plasmonic nanostructured aluminum substrates were designed to provide resonant near field concentration at λ = 248 nm (5 eV), corresponding to the maximum optical cross section for hydrogen abstraction from N{sub 2}H{sub 4}. We employed nanoimprint lithography to fabricate 1 mm × 1 mm arrays of the resonant plasmonic structures, and ultraviolet reflectance spectroscopy confirmed resonant extinction at 248 nm. Hydrazine was cryogenically adsorbed to the plasmonic substrate in a low-pressure ambient, and 5 eV surface plasmons were resonantly excited using a pulsed KrF laser. Mass spectrometry was used to characterize the photodissociation products and indicated a 6.2× overall enhancement in photodissociation yield for hydrazine adsorbed on plasmonic substrates compared with control substrates. The ultraviolet surface plasmon enhanced photodissociation demonstrated here may provide a valuable method to generate reactive precursors for deposition of nitride thin film materials at low temperatures.

  13. Theoretical study of cathode surfaces and high-temperature superconductors

    NASA Technical Reports Server (NTRS)

    Mueller, Wolfgang

    1994-01-01

    The surface-dipole properties of model cathode surfaces have been investigated with relativistic scattered-wave cluster calculations. Work-function/coverage curves have been derived from these data by employing the depolarization model of interacting surface dipoles. Accurate values have been obtained for the minimum work functions of several low-work-function surfaces. In the series BaO on bcc W, hcp Os, and fcc Pt, BaO/Os shows a lower and BaO/Pt a higher work function than BaO/W, which is attributed to the different substrate crystal structures involved. Results are also presented on the electronic structure of the high-temperature superconductor YBa2Cu3O7, which has been investigated with fully relativistic calculations for the first time.

  14. The extent of temporal smearing in surface-temperature histories derived from borehole temperature measurements

    USGS Publications Warehouse

    Clow, G.D.

    1992-01-01

    The ability of borehole temperature data to resolve past climatic events is investigated using Backus-Gilbert inversion methods. Two experimental approaches are considered: (1) the data consist of a single borehole temperature profile, and (2) the data consist of climatically-induced temperature transients measured within a borehole during a monitoring experiment. The sensitivity of the data's resolving power to the vertical distribution of the measurements, temperature measurement errors, the inclusion of a local meteorological record, and the duration of a monitoring experiment, are investigated. The results can be used to help interpret existing surface temperature histories derived from borehole temperature data and to optimize future experiments for the detection of climatic signals. ?? 1992.

  15. Interdecadal changes of surface temperature since the late nineteenth century

    SciTech Connect

    Parker, D.E.; Folland, C.K.; Bevan, A.; Jones, P.D.

    1994-07-20

    The authors present global fields of decadal annual surface temperature anomalies, referred to the period 1951-1980, for each decade from 1881-1890 to 1981-1990 and for 1984-1993. In addition, they show decadal calendar-seasonal anomaly fields for the warm decades 1936-1945 and 1981-1990. The fields are based on sea surface temperature (SST) and land surface air temperature data. The SSTs are corrected for the pre-World War II use of uninsulated sea temperature buckets and incorporate adjusted satellite-based SSTs from 1982 onward. These results extend those published in the 1990 Intergovernmental Panel on Climate Change Scientific Assessment. Despite poor data coverage initially and around the two World Wars the generally cold end of the nineteenth century and start to the twentieth century are confirmed, together with the substantial warming between about 1920 and 1940. Slight cooling of the northern hemisphere took place between the 1950s and the mid-1970s, although slight warming continued south of the equator. Recent warmth has been most marked over the northern continents in winter and spring, but the 1980s were warm almost everywhere apart from Greenland, the northwestern Atlantic and the midlatitude North Pacific. Parts of the middle- to high-latitude southern ocean may also have been cool in the 1980s, but in this area the 1951-1980 climatology is unreliable. The impact of the satellite data is reduced because the record of blended satellite and in situ SST is still too short to yield a climatology from which to calculate representative anomalies reflecting climatic change in the southern ocean. However, the authors propose a method of using existing satellite data in a step toward this target. The maps are condensed into global and hemispheric decadal surface temperature anomalies. The authors show the sensitivity of these estimated anomalies to alternative methods of compositing the spatially incomplete fields. 58 refs., 17 figs., 3 tabs.

  16. Sea-surface temperature and salinity mapping from remote microwave radiometric measurements of brightness temperature

    NASA Technical Reports Server (NTRS)

    Hans-Juergen, C. B.; Kendall, B. M.; Fedors, J. C.

    1977-01-01

    A technique to measure remotely sea surface temperature and salinity was demonstrated with a dual frequency microwave radiometer system. Accuracies in temperature of 1 C and in salinity of part thousand for salinity greater than 5 parts per thousand were attained after correcting for the influence of extraterrestrial background radiation, atmospheric radiation and attenuation, sea-surface roughness, and antenna beamwidth. The radiometers, operating at 1.43 and 2.65 GHz, comprise a third-generation system using null balancing and feedback noise injection. Flight measurements from an aircraft at an altitude of 1.4 km over the lower Chesapeake Bay and coastal areas of the Atlantic Ocean resulted in contour maps of sea-surface temperature and salinity with a spatial resolution of 0.5 km.

  17. Significant improvement in IR surface-temperature measurements

    SciTech Connect

    Briles, S.D.; Bennett, G.A.; Larkin, T.H.; Worcester, P.

    1989-06-01

    Obtaining infrared (IR) surface-temperature measurements of miniature square targets on the order of 1.6 mm with a spatial resolution of 15 ..mu..m has recently become possible using the Barnes Engineering Computherm System, but the accuracy and precision of the measurements have been limited. The objective of this work is to provide a calibration procedure that will improve by a factor of 8 the accuracy and precision of the two-dimensional temperature measurement. The IR microscope detects energy emitted by the target and displays it as a radiance image. Heating the target to two known temperatures permits calculation of the target emissivity using the radiances at each pixel in the two-dimensional field. An error is induced in the emissivity calculation by substituting the thermal-well temperature for the known target surface temperature. At the same time, the radiance image is distorted by two functions that affect the measurement accuracy. The precision of the instrument is altered by a random noise field function. The noise functions were investigated to determine whether they were added to or multiplied by the radiance equation. A plot of image-radiance means shows the same trends as the added noise functions suggested by the prediction. Correction of the induced distortions improved the accuracy noticeably. Further improvement in the accuracy is accomplished by using a syringe thermocouple to measure the actual surface temperatures used for the emissivity calculations. Investigation of the random noise field shows that it is zero-mean and Gaussian in nature. We can therefore average images over time to improve the precision. 9 refs., 12 figs., 1 tab.

  18. Piglets’ Surface Temperature Change at Different Weights at Birth

    PubMed Central

    Caldara, Fabiana Ribeiro; dos Santos, Luan Sousa; Machado, Sivanilza Teixeira; Moi, Marta; de Alencar Nääs, Irenilza; Foppa, Luciana; Garcia, Rodrigo Garófallo; de Kássia Silva dos Santos, Rita

    2014-01-01

    The study was carried out in order to verify the effects of piglets’ weight at birth on their surface temperature change (ST) after birth, and its relationship with ingestion time of colostrum. Piglets from four different sows were weighed at birth and divided into a totally randomized design with three treatments according to birth weight (PBW): T1 - less than 1.00 kg, T2 - 1.00 to 1.39 kg, and T3 - higher than or equal to 1.40 kg. The time spent for the first colostrum ingestion was recorded (TFS). Images of piglets’ surface by thermal imaging camera were recorded at birth (STB) and 15, 30, 45, 60, and 120 min after birth. The air temperature and relative humidity were recorded every 30 min and the indexes of temperature and humidity (THI) were calculated. A ST drop after 15 min from birth was observed, increasing again after sixty minutes. Positive correlations were found between the PBW and the ST at 30 and 45 min after birth. The PBW was negatively correlated with the TFS. The THI showed high negative correlations (−0.824 and −0.815) with STB and after 15 min from birth. The piglet’s surface temperature at birth was positively correlated with temperature thereof to 15 min, influencing therefore the temperatures in the interval of 45 to 120 min. The birth weight contributes significantly to postnatal hypothermia and consequently to the time it takes for piglets ingest colostrum, requiring special attention to those of low birth weight. PMID:25049971

  19. High Predictive Skill of Global Surface Temperature a Year Ahead

    NASA Astrophysics Data System (ADS)

    Folland, C. K.; Colman, A.; Kennedy, J. J.; Knight, J.; Parker, D. E.; Stott, P.; Smith, D. M.; Boucher, O.

    2011-12-01

    We discuss the high skill of real-time forecasts of global surface temperature a year ahead issued by the UK Met Office, and their scientific background. Although this is a forecasting and not a formal attribution study, we show that the main instrumental global annual surface temperature data sets since 1891 are structured consistently with a set of five physical forcing factors except during and just after the second World War. Reconstructions use a multiple application of cross validated linear regression to minimise artificial skill allowing time-varying uncertainties in the contribution of each forcing factor to global temperature to be assessed. Mean cross validated reconstructions for the data sets have total correlations in the range 0.93-0.95,interannual correlations in the range 0.72-0.75 and root mean squared errors near 0.06oC, consistent with observational uncertainties.Three transient runs of the HadCM3 coupled model for 1888-2002 demonstrate quite similar reconstruction skill from similar forcing factors defined appropriately for the model, showing that skilful use of our technique is not confined to observations. The observed reconstructions show that the Atlantic Multidecadal Oscillation (AMO) likely contributed to the re-commencement of global warming between 1976 and 2010 and to global cooling observed immediately beforehand in 1965-1976. The slowing of global warming in the last decade is likely to be largely due to a phase-delayed response to the downturn in the solar cycle since 2001-2, with no net ENSO contribution. The much reduced trend in 2001-10 is similar in size to other weak decadal temperature trends observed since global warming resumed in the 1970s. The causes of variations in decadal trends can be mostly explained by variations in the strength of the forcing factors. Eleven real-time forecasts of global mean surface temperature for the year ahead for 2000-2010, based on broadly similar methods, provide an independent test of the

  20. Surface Fatigue Life of High Temperature Gear Materials

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.

    1994-01-01

    Three high temperature gear materials were evaluated using spur gear surface fatigue tests. These materials were, VASCO max 350, VASCO matrix 2, and nitralloy N and were evaluated for possible use in high temperature gear applications. The fatigue life of the three high temperature gear materials were compared with the life of the standard AISI 9310 aircraft gear material. Surface fatigue tests were conducted at a lubricant inlet temperature of 321 K (120 F), a lubricant outlet temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), a speed of 10,000 rpm, and with a synthetic paraffinic lubricant. The life of the nitralloy N was approximately the same as the AISI 9310, the life of the VASCO max 350 was much less than the AISI 9310 while the life of the VASCO matrix 2 was several times the life of the AISI 9310. The VASCO max 350 also showed very low fracture toughness with approximately half of the gears failed by tooth fracture through the fatigue spall. The VASCO matrix 2 had approximately 10-percent fracture failure through the fatigue spalls indicating moderate to good fracture toughness.

  1. Atmospheric carbon dioxide and chlorofluoromethanes - Combined effects on stratospheric ozone, temperature, and surface temperature

    NASA Technical Reports Server (NTRS)

    Callis, L. B.; Natarajan, M.

    1981-01-01

    The effects of combined CO2 and CFCl3 and CF2Cl2 time-dependent scenarios on atmospheric O3 and temperature are described; the steady-state levels of O3 and surface temperature, to which the chlorofluoromethane scenario tends in the presence of twice and four time ambient CO2, are examined; and surface temperature changes, caused by the combined effects, are established. A description of the model and of the experiments is presented. Results indicate that (1) the total ozone time history is significantly different from that due to the chlorofluoromethane alone; (2) a local ozone minimum occurs in the upper stratosphere about 45 years from the present with a subsequent ozone increase, then decline; and (3) steady-state solutions indicate that tropospheric temperature and water vapor increases, associated with increased infrared opacity, cause significant changes in tropospheric ozone levels for 2 x CO2 and 4 x CO2, without the addition of chlorofluoromethanes.

  2. The dependence of surface temperature on IGBTs load and ambient temperature

    NASA Astrophysics Data System (ADS)

    Alexander, Čaja; Marek, Patsch

    2015-05-01

    Currently, older power electronics and electrotechnics are improvement and at the same time developing new and more efficient devices. These devices produce in their activities a significant part of the heat which, if not effectively drained, causing damage to these elements. In this case, it is important to develop new and more efficient cooling system. The most widespread of modern methods of cooling is the cooling by heat pipe. This contribution is aimed at cooling the insulated-gate bipolar transistor (IGBT) elements by loop heat pipe (LHP). IGBTs are very prone to damage due to high temperatures, and therefore is the important that the surface temperature was below 100°C. It was therefore created a model that examined what impact of surface temperature on the IGBT element and heat removal at different load and constant ambient temperature.

  3. The PRISM palaeoclimate reconstruction and Pliocene sea-surface temperature

    USGS Publications Warehouse

    Dowsett, H.J.

    2007-01-01

    In this paper, I present a summary of the Pliocene Research, Inte