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Sample records for actual evapotranspiration eta

  1. Estimating riparian and agricultural actual evapotranspiration by reference evapotranspiration and MODIS Enhanced Vegetation Index

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dryland river basins frequently support both irrigated agriculture and riparian vegetation and remote sensing methods are needed to monitor water use by both crops and natural vegetation in these districts. We developed a general algorithm for estimating actual evapotranspiration (ETa) based on the ...

  2. Alternate corrections for estimating actual wetland evapotranspiration from potential evapotranspiration

    USGS Publications Warehouse

    Barclay, Shoemaker W.; Sumner, D.M.

    2006-01-01

    Corrections can be used to estimate actual wetland evapotranspiration (AET) from potential evapotranspiration (PET) as a means to define the hydrology of wetland areas. Many alternate parameterizations for correction coefficients for three PET equations are presented, covering a wide range of possible data-availability scenarios. At nine sites in the wetland Everglades of south Florida, USA, the relatively complex PET Penman equation was corrected to daily total AET with smaller standard errors than the PET simple and Priestley-Taylor equations. The simpler equations, however, required less data (and thus less funding for instrumentation), with the possibility of being corrected to AET with slightly larger, comparable, or even smaller standard errors. Air temperature generally corrected PET simple most effectively to wetland AET, while wetland stage and humidity generally corrected PET Priestley-Taylor and Penman most effectively to wetland AET. Stage was identified for PET Priestley-Taylor and Penman as the data type with the most correction ability at sites that are dry part of each year or dry part of some years. Finally, although surface water generally was readily available at each monitoring site, AET was not occurring at potential rates, as conceptually expected under well-watered conditions. Apparently, factors other than water availability, such as atmospheric and stomata resistances to vapor transport, also were limiting the PET rate. ?? 2006, The Society of Wetland Scientists.

  3. Controls over spatial and temporal variations in annual actual evapotranspiration in snow-free California watersheds

    NASA Astrophysics Data System (ADS)

    Clark, Allison Marie

    Actual evapotranspiration (Eta) is one of the largest components of the hydrologic budget and accounts for a majority of water lost from a watershed. It is primarily controlled by soil water availability, which is largely controlled by rainfall, and atmospheric demand (potential evapotranspiration). Consequently, Eta is sensitive to changes in meteorologic conditions. Understanding the relationship between Et a and controlling meteorologic variables across time and space is important for future predictions of Eta under a changing climate, especially in California where demand for surface and groundwater is high. A regression modeling approach was used to (1) determine the relative control of rainfall, rainfall intensity, and potential evapotranspiration (Etp) over annual and long-term mean annual Eta across watersheds in western California, and (2) quantify the sensitivity of watershed annual Eta to changes in these variables. Annual Eta data for 20 snow-free California watersheds was derived using the water balance method for hydrologic years 1982-2011. Independent variables examined in this study were annual rainfall, rainfall intensity, and potential evapotranspiration. These quantities were obtained or calculated from daily PRISM rainfall and temperature datasets. Results indicated that rainfall was the dominant control over variations in mean annual Eta across the study region (Adj. R2 0.935) and was the primary control over interannual variations in Et a for 15 out of 17 study watersheds. Rainfall intensity was a significant but weaker predictor of mean annual Eta (adj. R2 0.833) and was a significant predictor of annual variations in Eta for 12 out of 17 watersheds. A weak relationship between Etp and Eta was observed across the study region (adj. R2 = 0.660) and the relationship was found to be negative. Etp was a significant, though weak, predictor of annual Eta for 8 out of 17 watersheds. The amount of variance in annual Eta explained by rainfall

  4. Establishing seasonal chronicles of actual evapotranspiration under sloping conditions

    NASA Astrophysics Data System (ADS)

    Zitouna Chebbi, R.; Prévot, L.; Jacob, F.; Voltz, M.

    2012-04-01

    Estimation of daily and seasonal actual evapotranspiration (ETa) is strongly needed for hydrological and agricultural purposes. Although the eddy covariance method is well suited for such estimation of land surface fluxes, this method suffers from limitations when establishing long time series. Missing data are often encountered, resulting from bad meteorological conditions, rejection by quality control tests, power failures… Numerous gap fill techniques have been proposed in the literature but there applicability in sloping conditions is not well known. In order to estimate ETa over long periods (agricultural cycle) on crops cultivated in sloping areas, a pluri-annual experiment was conducted in the Kamech catchment, located in North-eastern Tunisia. This Mediterranean site is characterized by a large heterogeneity in topography, soils and crops. Land surface fluxes were measured using eddy covariance systems. Measurements were collected on the two opposite sides of the Kamech V-shaped catchment, within small fields having slopes steeper than 5%. During three different years, four crops were studied: durum wheat, oat, fava bean and pasture. The topography of the catchment and the wind regime induced upslope and downslope flows over the study fields. In this study, we showed that gap filling of the turbulent fluxes (sensible and latent heat) can be obtained through linear regressions against net radiation. To account for the effect of the topography, linear regressions were calibrated by distinguishing upslope and downslope flows. This significantly improved the quality of the reconstructed data over 30 minute intervals. This gap filling technique also improved the energy balance closure at the daily time scale. As a result, seasonal chronicles of daily ETa throughout the growth cycle of the study crops in the Kamech watershed were established, thus providing useful information about the water use of annual crops in a semi-arid rainfed and hilly area.

  5. Simultaneous estimation of precipitation and actual evapotranspiration by lysimeters - Comparison with tipping bucket and eddy covariance

    NASA Astrophysics Data System (ADS)

    Hendricks Franssen, H. J.; Gebler, S.; Puetz, T.; Post, H.; Schmidt, M.; Vereecken, H.

    2014-12-01

    Although precipitation and actual evapotranspiration measurements have a long tradition, accurate estimates of precipitation (P) and actual evapotranspiration (ETa) remain a challenge. Our study compares actual evapotranspiration estimates acquired with the Eddy-Covariance (EC) method and ETa measurements by a set of six redundant weighable lysimeters for a managed grassland site at Rollesbroich (Eifel, Western Germany). The comparison of ETa measured by EC (accounting for energy balance deficit correction) and by lysimeters is hardly reported in literature and gains more insight into the performance of both techniques. The evaluation of ETa estimates by both methods for the year 2012 shows a good agreement with a total difference of ca. 4 %, which is mainly related to variations in grass height at the lysimeters and in the EC footprint. We also used the lysimeter records to estimate precipitation amounts in combination with the AWAT filter algorithm. The estimated precipitation volumes of the lysimeter measurements show significant differences compared to the precipitation data of the Hellman type tipping bucket rain gauge at the test site. For the entire year 2012 the lysimeter measurements exhibit a 16 % higher precipitation amount than the tipping bucket data. With help of an on-site video surveillance system the precipitation data of the lysimeters were investigated in more detail. It was found that the precipitation surplus in lysimeter records in part is related to the detection of rime and dew, which contributes 17 % to the yearly difference between both methods. We concluded that weighable lysimeter data can be used to simultaneously estimate precipitation and actual evapotranspiration in a reliable fashion. Furthermore, lysimeter allow a plausible detection of rime and dew in contrast to standard rain gauges.

  6. Integrating MODIS and Landsat Data Using the Simplified Surface Energy Balance Approach to Estimate Actual Evapotranspiration at Multiple Scales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimating actual evapotranspiration (ETa) in space and time is critical for developing useful basin water balance models and for monitoring vegetation water use and drought severity analysis. In this study, we combined MODIS and Landsat thermal data using a 'time-limited' stable fractional relation...

  7. Using lysimeters to test the Penman Monteith actual evapotranspiration.

    NASA Astrophysics Data System (ADS)

    Ben Asher, Jiftah; Volinski, Roman; Zilberman, Arkadi; Bar Yosef, Beni; Silber, Avner

    2015-04-01

    Differences in actual transpiration (ETa) of banana plants were quantified in a lysimeter experiment. ETA was computed using instantaneous data from two weighing lysimeters and compared to PM (Penman-Monteith) model for ETa. Two critical problems were faced in this test. A) Estimating canopy and aerodynamic resistances ("rc" and "ra" respectively ) and B) converting the lysimeter changes in water volume ( LYv cm3 ) to ETa length units ( cm ). The two unknowns " rc" and "ra" were obtained from continuous measurements of the differences between canopy and air temperature (Tc - Ta). This difference was established by means of the infrared thermometry which was followed by numerical and analytical calculation of ETa using the modification suggested by R. Jackson to the PM model. The conversion of lysimeter volumetric units (LYv) to ETa length units was derived from the slope of cumulative LYv/ETa. This relationship was significantly linear (r2=0.97and 0.98.). Its slope was interpreted as "evaporating leaf area" which accounted for 1.8E4 cm2 in lysimeter 1 and 2.3E4 cm2.in lysimeter 2 . The comparison between LYv and PM model was acceptable even under very low ETa. The average of two lysimeters was 1.1mm/day (1.4 mm/day , LYv 1 and 0.8 LYv 2) while ETa calculated on the basis of PM model was 1.2 mm/day. It was concluded that although lysimeters are most accurate systems to measure ETa one of its disadvantages ( beside the high cost) is the volumetric output that in many cases should be supported by a one dimensional energy balance system. The PM model was found to be a reliable complementary tool to convert lysimeters volumetric output into conventional length units of ETa.

  8. Actual evapotranspiration and precipitation measured by lysimeters: a comparison with eddy covariance and tipping bucket

    NASA Astrophysics Data System (ADS)

    Gebler, S.; Hendricks Franssen, H.-J.; Pütz, T.; Post, H.; Schmidt, M.; Vereecken, H.

    2014-12-01

    This study compares actual evapotranspiration (ETa) measurements by a set of six weighable lysimeters, ETa estimates obtained with the eddy covariance (EC) method, and potential crop evapotranspiration according to FAO (ETc-FAO) for the Rollesbroich site in the Eifel (Western Germany). The comparison of ETa measured by EC (including correction of the energy balance deficit) and by lysimeters is rarely reported in literature and allows more insight into the performance of both methods. An evaluation of ETa for the two methods for the year 2012 shows a good agreement with a total difference of 3.8% (19 mm) between the ETa estimates. The highest agreement and smallest relative differences (<8%) on monthly basis between both methods are found in summer. ETa was close to ETc-FAO, indicating that ET was energy limited and not limited by water availability. ETa differences between lysimeter, ETc-FAO, and EC were mainly related to differences in grass height caused by harvesting management and the EC footprint. The lysimeter data were also used to estimate precipitation amounts in combination with a filter algorithm for high precision lysimeters recently introduced by Peters et al. (2014). The estimated precipitation amounts from the lysimeter data show significant differences compared to the precipitation amounts recorded with a standard rain gauge at the Rollesbroich test site. For the complete year 2012 the lysimeter records show a 16% higher precipitation amount than the tipping bucket. With the help of an on-site camera the precipitation measurements of the lysimeters were analyzed in more detail. It was found that the lysimeters record more precipitation than the tipping bucket in part related to the detection of rime and dew, which contributes 17% to the yearly difference between both methods. In addition, fog and drizzle explain an additional 5.5% of the total difference. Larger differences are also recorded for snow and sleet situations. During snowfall, the

  9. Actual evapotranspiration and precipitation measured by lysimeters: a comparison with eddy covariance and tipping bucket

    NASA Astrophysics Data System (ADS)

    Gebler, S.; Hendricks Franssen, H.-J.; Pütz, T.; Post, H.; Schmidt, M.; Vereecken, H.

    2015-05-01

    This study compares actual evapotranspiration (ETa) measurements by a set of six weighable lysimeters, ETa estimates obtained with the eddy covariance (EC) method, and evapotranspiration calculated with the full-form Penman-Monteith equation (ETPM) for the Rollesbroich site in the Eifel (western Germany). The comparison of ETa measured by EC (including correction of the energy balance deficit) and by lysimeters is rarely reported in the literature and allows more insight into the performance of both methods. An evaluation of ETa for the two methods for the year 2012 shows a good agreement with a total difference of 3.8% (19 mm) between the ETa estimates. The highest agreement and smallest relative differences (< 8%) on a monthly basis between both methods are found in summer. ETa was close to ETPM, indicating that ET was energy limited and not limited by water availability. ETa differences between lysimeter and EC were mainly related to differences in grass height caused by harvest and the EC footprint. The lysimeter data were also used to estimate precipitation amounts in combination with a filter algorithm for the high-precision lysimeters recently introduced by Peters et al. (2014). The estimated precipitation amounts from the lysimeter data differ significantly from precipitation amounts recorded with a standard rain gauge at the Rollesbroich test site. For the complete year 2012 the lysimeter records show a 16 % higher precipitation amount than the tipping bucket. After a correction of the tipping bucket measurements by the method of Richter (1995) this amount was reduced to 3%. With the help of an on-site camera the precipitation measurements of the lysimeters were analyzed in more detail. It was found that the lysimeters record more precipitation than the tipping bucket, in part related to the detection of rime and dew, which contribute 17% to the yearly difference between both methods. In addition, fog and drizzle explain an additional 5.5% of the total

  10. Merging raster meteorological data with low resolution satellite images for improved estimation of actual evapotranspiration

    NASA Astrophysics Data System (ADS)

    Cherif, Ines; Alexandridis, Thomas; Chambel Leitao, Pedro; Jauch, Eduardo; Stavridou, Domna; Iordanidis, Charalampos; Silleos, Nikolaos; Misopolinos, Nikolaos; Neves, Ramiro; Safara Araujo, Antonio

    2013-04-01

    Actual evapotranspiration (ETa) can be estimated using Energy Balance models and remotely sensed data. In particular, satellite images acquired in visible, near and thermal infrared parts of the spectrum have been used with the Surface Energy Balance Algorithm for Land (SEBAL) to estimate actual evapotranspiration. This algorithm is solving the Energy Balance Equation using data from a meteorological station present in the vicinity, and assumes the meteorological conditions homogeneous over the study area. Most often, data from a representative weather station are used. This assumption may lead to substantial errors in areas with high spatial variability in weather parameters. In this paper, the ITA-MyWater algorithms (Integrated Thermodynamic Algorithms for MyWater project), an adaptation of SEBAL was merged together with spatially distributed meteorological data to increase the accuracy of ETa estimations at regional scale using MODIS satellite images. The major changes introduced to migrate from point to raster are that (i) air temperature and relative humidity maps are used for the estimation of the Energy Balance terms, including instantaneous net radiation and soil heat flux and (ii) the variability of wind speed is taken into account to generate maps of the aerodynamic resistance, sensible heat flux and difference between soil and air temperature at the boundary conditions (at dry and wet pixels). The approach was applied in the river basin of Tamega in Portugal, where actual evapotranspiration was estimated for several MODIS 8-day periods from spring to winter of the same year. The raster meteorological maps were produced by the MM5 weather forecast model. Daily reference evapotranspiration was calculated with MOHID LAND model. Using a temporal integration technique and the daily reference evapotranspiration maps, the cumulative evapotranspiration over the MODIS 8-day period was estimated and compared to the global evapotranspiration MODIS product (MOD16A2

  11. Remote sensing estimates of actual evapotranspiration in an irrigation district

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate estimates of the spatial distribution of actual evapotranspiration (AET) are useful in hydrology, but can be difficult to obtain. Remote sensing provides a potential capability for routinely monitoring AET by combining remotely sensed surface temperature and vegetation cover observations w...

  12. Actual evapotranspiration modeling using the operational Simplified Surface Energy Balance (SSEBop) approach

    USGS Publications Warehouse

    Savoca, Mark E.; Senay, Gabriel B.; Maupin, Molly A.; Kenny, Joan F.; Perry, Charles A.

    2013-01-01

    Remote-sensing technology and surface-energy-balance methods can provide accurate and repeatable estimates of actual evapotranspiration (ETa) when used in combination with local weather datasets over irrigated lands. Estimates of ETa may be used to provide a consistent, accurate, and efficient approach for estimating regional water withdrawals for irrigation and associated consumptive use (CU), especially in arid cropland areas that require supplemental water due to insufficient natural supplies from rainfall, soil moisture, or groundwater. ETa in these areas is considered equivalent to CU, and represents the part of applied irrigation water that is evaporated and/or transpired, and is not available for immediate reuse. A recent U.S. Geological Survey study demonstrated the application of the remote-sensing-based Simplified Surface Energy Balance (SSEB) model to estimate 10-year average ETa at 1-kilometer resolution on national and regional scales, and compared those ETa values to the U.S. Geological Survey’s National Water-Use Information Program’s 1995 county estimates of CU. The operational version of the operational SSEB (SSEBop) method is now used to construct monthly, county-level ETa maps of the conterminous United States for the years 2000, 2005, and 2010. The performance of the SSEBop was evaluated using eddy covariance flux tower datasets compiled from 2005 datasets, and the results showed a strong linear relationship in different land cover types across diverse ecosystems in the conterminous United States (correlation coefficient [r] ranging from 0.75 to 0.95). For example, r for woody savannas (0.75), grassland (0.75), forest (0.82), cropland (0.84), shrub land (0.89), and urban (0.95). A comparison of the remote-sensing SSEBop method for estimating ETa and the Hamon temperature method for estimating potential ET (ETp) also was conducted, using regressions of all available county averages of ETa for 2005 and 2010, and yielded correlations of r = 0

  13. Actual Evapotranspiration using a two source energy balance model and gridded reference ET0

    NASA Astrophysics Data System (ADS)

    Geli, H. M.; Neale, C. M.; Verdin, J. P.; Senay, G. B.; Hobbins, M.

    2013-12-01

    In an ongoing effort to provide estimates of actual evapotranspiration (ETa) at different spatial scales from local to regional this study investigate the use of a newly under development gridded reference ET0 product. This study is conducted within the context of a USGS project aimed to provide a standardized framework for the remote sensing of ETa that can be followed in the implementation of the WaterSMART program. Most thermal remote sensing based models provide instantaneous estimates of latent heat flux which then can be extrapolated to daily ETa. In many cases extrapolation is achieved using the ETref method. At field scales reference ET0, daily and instantaneous values, are obtained from point-based/local scale measurements. When considering regional scale this local scale estimates of ET0 might not be appropriate to account for the corresponding spatial variability. This analysis provides a comparison of ETa estimates based on a two source energy balance approach using point-based and gridded reference ET0 data. The two source energy balance SEBS (Norman et al. 1995) is used to calculate surface energy fluxes and ETa. Data from Palo Verdi Irrigation District (PVID), CA is used during the analysis. The area which extends over 500 km2 covered mostly with alfalfa, cotton and vegetable crops. Ground-based hydrometeorological data including reference ET0 are provided from a nearby weather stations. CONUS wide gridded reference ET0 which being developed by NOAA using NLDAS-phase 2 weather forcing are used. Both estimates of ETa_point and ETa_NLDAS based on ground and gridded ET0 data, respectively, are compared to ground-based measurement. Preliminary results of the comparison will be presented to highlight on the potential use of such gridded ET0 data in the use of remote sensing of ETa at regional scales application. References Norman, J. M., W. P. Kustas, & K. S. Humes, 1995: A two-source approach for estimating soil and vegetation energy fluxes in

  14. Spatiotemporal variations of actual evapotranspiration over the Lake Selin Co Basin (Tibetan Plateau) during 2003-2012

    NASA Astrophysics Data System (ADS)

    Zhou, Jing; Wang, Lei

    2016-04-01

    Actual evapotranspiration (ETa) over the Tibetan Plateau (TP) is an important component of the water cycle, and greatly influences the water budgets of the TP lake basins. Quantitative estimation of ETa within lake basins is fundamental to physically understanding ETa changes, and thus will improve the understanding of the hydrological processes and energy balance throughout the lake basins. In this study, the spatiotemporal dynamic changes of ETa within the Lake Selin Co Basin (the TP's largest lake basin) during 2003-2012 are examined at the basin scale. This was carried out using the previously calibrated and validated Water and Energy Budget-based Distributed Hydrological Model (WEB-DHM) for the land area, the Penman-Monteith method for the water area when unfrozen, and a simple sublimation estimation approach for the water area when frozen. The relationship between ETa changes and controlling factors is also discussed. Results indicate that the simulated land ETa from the WEB-DHM reasonably agrees with the estimated ETa values from the nonlinear complementary relationship model using appropriately calibrated parameter values at a point scale. Land ETa displayed an insignificant increase of 7.03 mm/y, and largely depends on precipitation. For the water area, the combined effects of reduced wind speed and net radiation offset the effect of rising temperature and vapor pressure deficit, and contributed to an insignificant decrease in evaporation of 4.17 mm/y. Sensitivity analysis shows that vapor pressure deficit and wind speed are the most sensitive variables to the changes of evaporation from the water area.

  15. Soil water availability as controlling factor for actual evapotranspiration in urban soil-vegetation-systems

    NASA Astrophysics Data System (ADS)

    Thomsen, Simon; Reisdorff, Christoph; Gröngröft, Alexander; Jensen, Kai; Eschenbach, Annette

    2015-04-01

    The City of Hamburg is characterized by a large number of greens, parks and roadside trees: 600.000 trees cover about 14% of the city area, and moreover, 245.000 roadside trees can be found here. Urban vegetation is generally known to positively contribute to the urban micro-climate via cooling by evapotranspiration (ET). The water for ET is predominantly stored in the urban soils. Hence, the actual evapotranspiration (ETa) is - beside atmospheric drivers - determined by soil water availability at the soil surface and in the rooting zones of the respective vegetation. The overall aim of this study is to characterize soil water availability as a regulative factor for ETa in urban soil-vegetation systems. The specific questions addressed are: i) What is the spatio-temporal variation in soil water availability at the study sites? ii) Which soil depths are predominantly used for water uptake by the vegetation forms investigated? and iii) Which are the threshold values of soil water tension and soil water content (Θ), respectively, that limit ETa under dry conditions on both grass-dominated and tree-dominated sites? Three study areas were established in the urban region of Hamburg, Germany. We selected areas featuring both single tree stands and grass-dominated sites, both representing typical vegetation forms in Hamburg. The areas are characterized by relatively dry soil conditions. However, they differ in regard to soil water availability. At each area we selected one site dominated by Common Oak (Quercus ruber L.) with ages from 40 to 120 years, and paired each oak tree site with a neighboring grass-dominated site. All field measurements were performed during the years 2013 and 2014. At each site, we continuously measured soil water tension and Θ up to 160 cm depth, and xylem sap flux of each of three oak trees per site in a 15 min-resolution. Furthermore, we measured soil hydraulic properties as pF-curve, saturated and unsaturated conductivity at all sites

  16. Modeling actual evapotranspiration with routine meteorological variables in the data-scarce region of the Tibetan Plateau: Comparisons and implications

    NASA Astrophysics Data System (ADS)

    Ma, Ning; Zhang, Yinsheng; Xu, Chong-Yu; Szilagyi, Jozsef

    2015-08-01

    Quantitative estimation of actual evapotranspiration (ETa) by in situ measurements and mathematical modeling is a fundamental task for physical understanding of ETa as well as the feedback mechanisms between land and the ambient atmosphere. However, the ETa information in the Tibetan Plateau (TP) has been greatly impeded by the extremely sparse ground observation network in the region. Approaches for estimating ETa solely from routine meteorological variables are therefore important for investigating spatiotemporal variations of ETa in the data-scarce region of the TP. Motivated by this need, the complementary relationship (CR) and Penman-Monteith approaches were evaluated against in situ measurements of ETa on a daily basis in an alpine steppe region of the TP. The former includes the Nonlinear Complementary Relationship (Nonlinear-CR) as well as the Complementary Relationship Areal Evapotranspiration (CRAE) models, while the latter involves the Katerji-Perrier and the Todorovic models. Results indicate that the Nonlinear-CR, CRAE, and Katerji-Perrier models are all capable of efficiently simulating daily ETa, provided their parameter values were appropriately calibrated. The Katerji-Perrier model performed best since its site-specific parameters take the soil water status into account. The Nonlinear-CR model also performed well with the advantage of not requiring the user to choose between a symmetric and asymmetric CR. The CRAE model, even with a relatively low Nash-Sutcliffe efficiency (NSE) value, is also an acceptable approach in this data-scarce region as it does not need information of wind speed and ground surface conditions. In contrast, application of the Todorovic model was found to be inappropriate in the dry regions of the TP due to its significant overestimation of ETa as it neglects the effect of water stress on the bulk surface resistance. Sensitivity analysis of the parameter values demonstrated the relative importance of each parameter in the

  17. Actual evapotranspiration (water use) assessment of the Colorado River Basin at the Landsat resolution using the operational simplified surface energy balance model

    USGS Publications Warehouse

    Singh, Ramesh K.; Senay, Gabriel B.; Velpuri, Naga Manohar; Bohms, Stefanie; Russell L, Scott; Verdin, James P.

    2014-01-01

    Accurately estimating consumptive water use in the Colorado River Basin (CRB) is important for assessing and managing limited water resources in the basin. Increasing water demand from various sectors may threaten long-term sustainability of the water supply in the arid southwestern United States. We have developed a first-ever basin-wide actual evapotranspiration (ETa) map of the CRB at the Landsat scale for water use assessment at the field level. We used the operational Simplified Surface Energy Balance (SSEBop) model for estimating ETa using 328 cloud-free Landsat images acquired during 2010. Our results show that cropland had the highest ETa among all land cover classes except for water. Validation using eddy covariance measured ETa showed that the SSEBop model nicely captured the variability in annual ETa with an overall R2 of 0.78 and a mean bias error of about 10%. Comparison with water balance-based ETa showed good agreement (R2 = 0.85) at the sub-basin level. Though there was good correlation (R2 = 0.79) between Moderate Resolution Imaging Spectroradiometer (MODIS)-based ETa (1 km spatial resolution) and Landsat-based ETa (30 m spatial resolution), the spatial distribution of MODIS-based ETa was not suitable for water use assessment at the field level. In contrast, Landsat-based ETa has good potential to be used at the field level for water management. With further validation using multiple years and sites, our methodology can be applied for regular production of ETa maps of larger areas such as the conterminous United States.

  18. On the downscaling of actual evapotranspiration maps based on combination of MODIS and landsat-based actual evapotranspiration estimates

    USGS Publications Warehouse

    Singh, Ramesh K.; Senay, Gabriel B.; Velpuri, Naga Manohar; Bohms, Stefanie; Verdin, James P.

    2014-01-01

     Downscaling is one of the important ways of utilizing the combined benefits of the high temporal resolution of Moderate Resolution Imaging Spectroradiometer (MODIS) images and fine spatial resolution of Landsat images. We have evaluated the output regression with intercept method and developed the Linear with Zero Intercept (LinZI) method for downscaling MODIS-based monthly actual evapotranspiration (AET) maps to the Landsat-scale monthly AET maps for the Colorado River Basin for 2010. We used the 8-day MODIS land surface temperature product (MOD11A2) and 328 cloud-free Landsat images for computing AET maps and downscaling. The regression with intercept method does have limitations in downscaling if the slope and intercept are computed over a large area. A good agreement was obtained between downscaled monthly AET using the LinZI method and the eddy covariance measurements from seven flux sites within the Colorado River Basin. The mean bias ranged from −16 mm (underestimation) to 22 mm (overestimation) per month, and the coefficient of determination varied from 0.52 to 0.88. Some discrepancies between measured and downscaled monthly AET at two flux sites were found to be due to the prevailing flux footprint. A reasonable comparison was also obtained between downscaled monthly AET using LinZI method and the gridded FLUXNET dataset. The downscaled monthly AET nicely captured the temporal variation in sampled land cover classes. The proposed LinZI method can be used at finer temporal resolution (such as 8 days) with further evaluation. The proposed downscaling method will be very useful in advancing the application of remotely sensed images in water resources planning and management.

  19. Bowen ratio measurements above various vegetation covers and its comparison with actual evapotranspiration estimated by SoilClim model

    NASA Astrophysics Data System (ADS)

    Hlavinka, P.; Trnka, M.; Fischer, M.; Kucera, J.; Mozny, M.; Zalud, Z.

    2010-09-01

    The principle of Bowen ratio is one of the available techniques for measurements of actual evapotranspiration (ETa) as one of essential water balance fractions. The main aims of submitted study were: (i) to compare the water balance of selected crops, (ii) to compare outputs of SoilClim model with observed parameters (including ETa on Bowen ratio basis). The measurements were conducted at two experimental stations in the Czech Republic (Polkovice 49°23´ (N), 17°17´ (E), 205 m a.s.l.; Domanínek 49°32´ (N), 16°15´ (E), 544 m a.s.l.) during the years 2009 and 2010. Together with Bowen ratio the global solar radiation, radiation balance, soil heat flux, volumetric soil moisture and temperature within selected depths, precipitation and wind speed were measured. The measurements were conducted simultaneously above various covers within the same soil conditions: spring barley vs. winter wheat, spring barley vs. winter rape; grass vs. poplars; harvested field after tillage vs. harvested field after cereals without any tillage. The observed parameters from different covers were compared with SoilClim estimates. SoilClim model is modular software for water balance and soil temperature modelling and finally could be used for soil Hydric and Thermic regimes (according to USDA classification) identification. The core of SoilClim is based on modified FAO Penman-Monteith methodology. Submitted study proved the applicability of SoilClim model for ETa, soil moisture within two defined layers and soil temperature (in 0.5 m depth) estimates for various crops, covers, selected soil types and climatic conditions. Acknowledgement: We gratefully acknowledge the support of the Grant Agency of the Czech Republic (no. 521/09/P479) and the project NAZV QI91C054. The study was also supported by Research plan No. MSM6215648905 "Biological and technological aspects of sustainability of controlled ecosystems and their adaptability to climate change".

  20. Testing two temporal upscaling schemes for the estimation of the time variability of the actual evapotranspiration

    NASA Astrophysics Data System (ADS)

    Maltese, A.; Capodici, F.; Ciraolo, G.; La Loggia, G.

    2015-10-01

    Temporal availability of grapes actual evapotranspiration is an emerging issue since vineyards farms are more and more converted from rainfed to irrigated agricultural systems. The manuscript aims to verify the accuracy of the actual evapotranspiration retrieval coupling a single source energy balance approach and two different temporal upscaling schemes. The first scheme tests the temporal upscaling of the main input variables, namely the NDVI, albedo and LST; the second scheme tests the temporal upscaling of the energy balance output, the actual evapotranspiration. The temporal upscaling schemes were implemented on: i) airborne remote sensing data acquired monthly during a whole irrigation season over a Sicilian vineyard; ii) low resolution MODIS products released daily or weekly; iii) meteorological data acquired by standard gauge stations. Daily MODIS LST products (MOD11A1) were disaggregated using the DisTrad model, 8-days black and white sky albedo products (MCD43A) allowed modeling the total albedo, and 8-days NDVI products (MOD13Q1) were modeled using the Fisher approach. Results were validated both in time and space. The temporal validation was carried out using the actual evapotranspiration measured in situ using data collected by a flux tower through the eddy covariance technique. The spatial validation involved airborne images acquired at different times from June to September 2008. Results aim to test whether the upscaling of the energy balance input or output data performed better.

  1. Divergence of actual and reference evapotranspiration observations for irrigated sugarcane with windy tropical conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Standardized reference evapotranspiration (ET) and ecosystem-specific vegetation coefficients are frequently used to estimate actual ET. However, equations for calculating reference ET have not been well validated in more humid environments. We measured ET (ETEC) using Eddy Covariance (EC) towers a...

  2. Modelling bulk surface resistance from MODIS time series data to estimate actual regional evapotranspiration

    NASA Astrophysics Data System (ADS)

    Autovino, Dario; Minacapilli, Mario; Provenzano, Giuseppe

    2015-04-01

    Estimation of actual evapotraspiration by means of Penman-Monteith (P-M) equation requires the knowledge of the so-called 'bulk surface resistance', rc,act, representing the vapour flow resistance through the transpiring crop and evaporating soil surface. The accurate parameterization of rc,act still represents an unexploited topic, especially in the case of heterogeneous land surface. In agro-hydrological applications, the P-M equation commonly used to evaluate reference evapotranspiration (ET0) of a well-watered 'standardized crop' (grass or alfalfa), generally assumes for the bulk surface resistance a value of 70 s m-1. Moreover, specific crop coefficients have to be used to estimate maximum and/or actual evapotranspiration based on ET0. In this paper, a simple procedure for the indirect estimation of rc,act as function of a vegetation index computed from remote acquisition of Land Surface Temperature (LST), is proposed. An application was carried out in an irrigation district located near Castelvetrano, in South-West of Sicily, mainly cultivated with olive groves, in which actual evapotranspiration fluxes were measured during two years (2010-2011) by an Eddy Covariance flux tower (EC). Evapotranspiration measurements allowed evaluating rc,actbased on the numerical inversion of the P-M equation. In the same study area, a large time series of MODIS LST data, characterized by a spatial resolution of 1x1 km and a time step of 8-days, was also acquired for the period from 2000 to 2014. A simple Vegetation Index Temperatures (VTI), with values ranging from 0 to 1, was computed using normalized LST values. Evapotranspiration fluxes measured in 2010 were used to calibrate the relationship between rc,act and VTI, whereas data from 2011 were used for its validation. The preliminary results evidenced that, for the considered crop, an almost constant value of rc,act, corresponding to about 250 s m-1, can be considered typical of periods in which the crop is well

  3. A Coupled Remote Sensing and Simplified Surface Energy Balance Approach to Estimate Actual Evapotranspiration from Irrigated Fields

    PubMed Central

    Senay, Gabriel B.; Budde, Michael; Verdin, James P.; Melesse, Assefa M.

    2007-01-01

    Accurate crop performance monitoring and production estimation are critical for timely assessment of the food balance of several countries in the world. Since 2001, the Famine Early Warning Systems Network (FEWS NET) has been monitoring crop performance and relative production using satellite-derived data and simulation models in Africa, Central America, and Afghanistan where ground-based monitoring is limited because of a scarcity of weather stations. The commonly used crop monitoring models are based on a crop water-balance algorithm with inputs from satellite-derived rainfall estimates. These models are useful to monitor rainfed agriculture, but they are ineffective for irrigated areas. This study focused on Afghanistan, where over 80 percent of agricultural production comes from irrigated lands. We developed and implemented a Simplified Surface Energy Balance (SSEB) model to monitor and assess the performance of irrigated agriculture in Afghanistan using a combination of 1-km thermal data and 250-m Normalized Difference Vegetation Index (NDVI) data, both from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. We estimated seasonal actual evapotranspiration (ETa) over a period of six years (2000-2005) for two major irrigated river basins in Afghanistan, the Kabul and the Helmand, by analyzing up to 19 cloud-free thermal and NDVI images from each year. These seasonal ETa estimates were used as relative indicators of year-to-year production magnitude differences. The temporal water-use pattern of the two irrigated basins was indicative of the cropping patterns specific to each region. Our results were comparable to field reports and to estimates based on watershed-wide crop water-balance model results. For example, both methods found that the 2003 seasonal ETa was the highest of all six years. The method also captured water management scenarios where a unique year-to-year variability was identified in addition to water-use differences between

  4. A coupled remote sensing and simplified surface energy balance approach to estimate actual evapotranspiration from irrigated fields

    USGS Publications Warehouse

    Senay, G.B.; Budde, M.; Verdin, J.P.; Melesse, Assefa M.

    2007-01-01

    Accurate crop performance monitoring and production estimation are critical for timely assessment of the food balance of several countries in the world. Since 2001, the Famine Early Warning Systems Network (FEWS NET) has been monitoring crop performance and relative production using satellite-derived data and simulation models in Africa, Central America, and Afghanistan where ground-based monitoring is limited because of a scarcity of weather stations. The commonly used crop monitoring models are based on a crop water-balance algorithm with inputs from satellite-derived rainfall estimates. These models are useful to monitor rainfed agriculture, but they are ineffective for irrigated areas. This study focused on Afghanistan, where over 80 percent of agricultural production comes from irrigated lands. We developed and implemented a Simplified Surface Energy Balance (SSEB) model to monitor and assess the performance of irrigated agriculture in Afghanistan using a combination of 1-km thermal data and 250m Normalized Difference Vegetation Index (NDVI) data, both from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. We estimated seasonal actual evapotranspiration (ETa) over a period of six years (2000-2005) for two major irrigated river basins in Afghanistan, the Kabul and the Helmand, by analyzing up to 19 cloud-free thermal and NDVI images from each year. These seasonal ETa estimates were used as relative indicators of year-to-year production magnitude differences. The temporal water-use pattern of the two irrigated basins was indicative of the cropping patterns specific to each region. Our results were comparable to field reports and to estimates based on watershed-wide crop water-balance model results. For example, both methods found that the 2003 seasonal ETa was the highest of all six years. The method also captured water management scenarios where a unique year-to-year variability was identified in addition to water-use differences between

  5. Effects of precipitation and potential evaporation on actual evapotranspiration over the Laohahe basin, northern China

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Ren, L.; Yang, X.; Ma, M.; Yuan, F.; Jiang, S.

    2015-06-01

    Problems associated with water scarcity are facing new challenges under the climate change. As one of main consumptions in water cycle on the Earth, evapotranspiration plays a crucial role in regional water budget. In this paper, we employ two methods, i.e. hydrological sensitivity analysis and hydrological model simulation, to investigate the effect of climate variability and climatic change on actual evapotranspiration (Ea) within the Laohahe basin during 1964-2009. Calibrations of the two methods are firstly conducted during the baseline period (1964-1979), then with the two benchmarked models, simulations in climatic change duration (1980-2009) are further conducted and quantitative assessments on climatic change-induced variation of Ea are analysed accordingly. The results show that affected by combined impacts of decreased precipitation and potential evapotranspiration, variation of annual Ea in most sub-catchments suffer a downward trend during 1980-2009, with a higher descending rate in northern catchments. At decadal scale, Ea shows significant oscillation in accordance with precipitation patterns. Northern catchments generally suffer more decadal Ea changes than southern catchments, implying the impact of climatic change on decadal Ea is more intense in semi-arid areas than that in semi-humid regions. For whole changed durations, a general 0-20 mm reduction of Ea is found in most parts of studied region. For this water-limited region, Ea shows higher sensitivity to precipitation than to potential evaporation, which confirms the significant role of precipitation in controlling Ea patterns, whereas the impact of potential evapotranspiration variation would be negligible.

  6. [Spatiotemporal variation characteristics and related affecting factors of actual evapotranspiration in the Hun-Taizi River Basin, Northeast China].

    PubMed

    Feng, Xue; Cai, Yan-Cong; Guan, De-Xin; Jin, Chang-Jie; Wang, An-Zhi; Wu, Jia-Bing; Yuan, Feng-Hui

    2014-10-01

    Based on the meteorological and hydrological data from 1970 to 2006, the advection-aridity (AA) model with calibrated parameters was used to calculate evapotranspiration in the Hun-Taizi River Basin in Northeast China. The original parameter of the AA model was tuned according to the water balance method and then four subbasins were selected to validate. Spatiotemporal variation characteristics of evapotranspiration and related affecting factors were analyzed using the methods of linear trend analysis, moving average, kriging interpolation and sensitivity analysis. The results showed that the empirical parameter value of 0.75 of AA model was suitable for the Hun-Taizi River Basin with an error of 11.4%. In the Hun-Taizi River Basin, the average annual actual evapotranspiration was 347.4 mm, which had a slightly upward trend with a rate of 1.58 mm · (10 a(-1)), but did not change significantly. It also indicated that the annual actual evapotranspiration presented a single-peaked pattern and its peak value occurred in July; the evapotranspiration in summer was higher than in spring and autumn, and it was the smallest in winter. The annual average evapotranspiration showed a decreasing trend from the northwest to the southeast in the Hun-Taizi River Basin from 1970 to 2006 with minor differences. Net radiation was largely responsible for the change of actual evapotranspiration in the Hun-Taizi River Basin. PMID:25796880

  7. Estimation of actual evapotranspiration through model coupling and data assimilation with remotely sensed land surface properties

    NASA Astrophysics Data System (ADS)

    Kovalskyy, V.; Henebry, G.

    2009-05-01

    We report on preliminary results from the coupling of two models and satellite observations to track evapotranspiration (ET) dynamics in Northern Great Plains of the USA. The approach takes advantage of high- quality microclimate and irradiance/radiance measurements in a data assimilation scheme to estimate actual ET through a stepwise simulation of foliage dynamics, corrected by remotely sensed land surface properties. We used a recently developed VegET model that uses water balance principles and phenological constraints (Senay 2008) coupled with an event driven phenology model (EDPM) to simulate canopy dynamics unfolding in response to changing environmental conditions and disturbance events. We used NDVI derived from MODIS Collection 5 Nadir BRDF Adjusted Reflectance (NBAR; MCD43B4V5) to amend the outputs of the EDPM using one-dimensional Kalman filtering to achieve a better representation of changing canopy conditions. The model was trained on level 1 flux tower data from cropland sites at Mead, Nebraska and refined using similar records from Bondville, Illinois. Results from the test runs demonstrated the ability of EDPM to drive the phenological constrains of VegET with reasonable accuracy (RMSE 0.03-0.10 at Nebraska sites). Filtered and unfiltered results from the coupled model were compared with actual evapotranspiration recorded on flux towers and with tower NDVI (Wittich and Kraft 2008). Depending on vegetation type and location, Pearson correlation coefficients between model estimates and observed values ranged between 0.8 and 0.9.

  8. Estimation of Regional-Scale Actual Evapotranspiration in Okayama prefecture in Japan using Complementary Relationship

    NASA Astrophysics Data System (ADS)

    Moroizumi, T.; Yamamoto, M.; Miura, T.

    2008-12-01

    It is important to estimate accurately a water balance in watershed for proposing a reuse of water resources and a proper settlement of water utilization. Evapotranspiration (ET) is an important factor of water balance. Therefore, it is needed to estimate accurately the actual ET. The objective of this study is to estimate accurately monthly actual ET in Yoshii, Asahi, and Takahashi River watersheds in Okayama prefecture from 1999 to 2000. The monthly actual ET was calculated by a Morton and a modified Brutsaert and Stricker (B&S) method, using Automated Meteorological Data Acquisition Systems (AMeDAS) in the basin. The actual ET was estimated using land covers which were classified in 11 categories. The land covers includes the effects of albedo. The actual ET was related to the elevation at each AMeDAS station. Using this relationship, the actual ET at the 1 or 5 km grid-interval mesh in the basin was calculated, and finally, the distribution of actual ET was mapped. The monthly ET estimated by the modified B&S method were smaller than that by Morton method which showed a same tendency as the Penman potential ET (PET). The annual values of Morton"fs ET, modified B&S"fs ET, and PET were estimated as 796, 645, and 800 mm, respectively. The ET by the modified B&S was larger in hilly and mountainous areas than in settlement or city. In general, it was a reasonable result because city or settlement areas were covered with concrete and asphalt and the ET was controlled.

  9. Operational actual wetland evapotranspiration estimation for the Everglades using MODIS imagery

    NASA Astrophysics Data System (ADS)

    Melesse, Assefa; Cereon, Cristobal

    2014-05-01

    Wetlands are one of the most important ecosystems with varied functions and structures. Humans have drained wetlands and altered the structure and functions of wetlands for various uses. Wetland restoration efforts require assessment of the level of ecohydrological restoration for the intended functions. Among the various indicators of success in wetland restoration, achieving the desired water level (hydrology) is the most important, faster to achieve and easier to monitor than the establishment of the hydric soils and wetland vegetation. Monitoring wetland hydrology using remote sensing based evapotranspiration (ET) is a useful tool and approach since point measurements for understanding the temporal (before and after restoration) and spatial (impacted and restored) parts of the wetland are not effective for large areas. Evapotranspiration accounts over 80% of the water budget of the wetlands necessitating the need for spatiotemporal monitoring of ET flux. A study employing remotely sensed data from Moderate Resolution Imaging Spectroradiometer (MODIS) and modeling tools was conducted for a weekly spatial estimation of Everglades ET. Weekly surface temperature data were generated from the MODIS thermal band and evaporative fraction was estimated using the simplified surface energy balance (SSEB) approach. Based on the Simple Method, potential ET (PET) was estimated. Actual weekly wetland ET was computed as the (product of the PET and evaporative fraction). The ET product will be useful information for environmental restoration and wetland hydrology managers. The on-going restoration and monitoring work in the Everglades will benefit from this product and assist in evaluating progress and success in the restoration.

  10. Impacts of phenology on estimation of actual evapotranspiration with VegET model

    NASA Astrophysics Data System (ADS)

    Kovalskyy, V.; Henebry, G. M.

    2009-12-01

    The VegET model provides spatially explicit estimation of actual evapotranspiration (AET). Currently, it uses a climatology based on AVHRR NDVI image time series to modulate fluxes during growing seasons (Senay 2008). This step simplifies the model formulation, but it also introduces errors by ignoring the interannual variation in phenology. We report on a study to evaluate the effects of using an NDVI climatology in VegET rather than current season values. Using flux tower data from three sites across the US Corn Belt, we found that currently the model overestimates the duration of season. With the standard deviation of more than one week, the model results in an additional 50 to 70 mm of AET per season, which can account for about 10% of seasonal AET in drier western sites. The model showed only modest sensitivity to variation in growing season weather. This lack of sensitivity greatly decreased model accuracy during drought years: Pearson correlation coefficients between model estimates and observed values dropped from about 0.7 to 0.5, depending on vegetation type. We also evaluated an alternative approach to drive the canopy component of evapotranspiration, the Event Driven Phenology Model (EDPM). The parameterization of VegET with EDPM-simulated canopy dynamics improved the correlation by 0.1 or more and reduced the RMSE on daily AET estimates by 0.3 mm. By accounting for the progress of phenology during a particular growing season, the EDPM improves AET estimation over an NDVI climatology.

  11. Assessing daily actual evapotranspiration through energy balance: an experiment to evaluate the selfpreservation hypothesis with acquisition time

    NASA Astrophysics Data System (ADS)

    Maltese, A.; Capodici, F.; Ciraolo, G.; La Loggia, G.; Rallo, G.

    2013-10-01

    An operational use of the actual evapotranspiration estimates requires the integration from instantaneous to daily values. This can commonly be achieved under the hypothesis of daytime self-preservation of the evaporative fraction. In this study, it has been evaluated the effect of this assumption on the assessment of daily evapotranspiration from proximity sensing images acquired at hourly intervals over a homogeneous olive groove. Results have been validated by comparison with observations made by a micrometeorological (EC-flux tower) and an eco-physiological (sap flux) sensor. SEBAL model has been applied to thermal and multispectral images acquired during a clear day on August 2009 trough a FLIR A320G thermal camera and a Tetracam MCA II multispectral camera, installed on a tethered helium balloon. Thermal and multispectral images were characterized by very high spatial resolution. This experiment aims to analyze two effects: 1) the consistency of the self-preservation hypothesis for daily estimates of the actual evapotranspiration from hourly assessments at different times of the day; 2) the effects of the spatial resolution on the performances of the energy balance model. To evaluate the effects of the spatial resolution, semi-hourly observations made by a flux tower and sap-flow measures were compared to the evapotranspiration estimates performed using downscaled images at resolutions close to canopy sizes (2, 5 and 10 m). Results show that the best estimates are obtained with a spatial resolution comparable to the average size of the canopy with images taken approximately at 10 UTC.

  12. Actual evapotranspiration and deficit: Biologically meaningful correlates of vegetation distribution across spatial scales

    USGS Publications Warehouse

    Stephenson, N.L.

    1998-01-01

    Correlative approaches to understanding the climatic controls of vegetation distribution have exhibited at least two important weaknesses: they have been conceptually divorced across spatial scales, and their climatic parameters have not necessarily represented aspects of climate of broad physiological importance to plants. Using examples from the literature and from the Sierra Nevada of California, I argue that two water balance parameters-actual evapotranspiration (AET) and deficit (D)-are biologically meaningful, are well correlated with the distribution of vegetation types, and exhibit these qualities over several orders of magnitude of spatial scale (continental to local). I reach four additional conclusions. (1) Some pairs of climatic parameters presently in use are functionally similar to AET and D; however, AET and D may be easier to interpret biologically. (2) Several well-known climatic parameters are biologically less meaningful or less important than AET and D, and consequently are poorer correlates of the distribution of vegetation types. Of particular interest, AET is a much better correlate of the distributions of coniferous and deciduous forests than minimum temperature. (3) The effects of evaporative demand and water availability on a site's water balance are intrinsically different. For example, the 'dry' experienced by plants on sunward slopes (high evaporative demand) is not comparable to the 'dry' experienced by plants on soils with low water-holding capacities (low water availability), and these differences are reflected in vegetation patterns. (4) Many traditional topographic moisture scalars-those that additively combine measures related to evaporative demand and water availability are not necessarily meaningful for describing site conditions as sensed by plants; the same holds for measured soil moisture. However, using AET and D in place of moisture scalars and measured soil moisture can solve these problems.

  13. Divergence of actual and reference evapotranspiration observations for irrigated sugarcane with windy tropical conditions

    NASA Astrophysics Data System (ADS)

    Anderson, R. G.; Wang, D.; Tirado-Corbalá, R.; Zhang, H.; Ayars, J. E.

    2015-01-01

    Standardized reference evapotranspiration (ET) and ecosystem-specific vegetation coefficients are frequently used to estimate actual ET. However, equations for calculating reference ET have not been well validated in tropical environments. We measured ET (ETEC) using eddy covariance (EC) towers at two irrigated sugarcane fields on the leeward (dry) side of Maui, Hawaii, USA in contrasting climates. We calculated reference ET at the fields using the short (ET0) and tall (ETr) vegetation versions of the American Society for Civil Engineers (ASCE) equation. The ASCE equations were compared to the Priestley-Taylor ET (ETPT) and ETEC. Reference ET from the ASCE approaches exceeded ETEC during the mid-period (when vegetation coefficients suggest ETEC should exceed reference ET). At the windier tower site, cumulative ETr exceeded ETEC by 854 mm over the course of the mid-period (267 days). At the less windy site, mid-period ETr still exceeded ETEC, but the difference was smaller (443 mm). At both sites, ETPT approximated mid-period ETEC more closely than the ASCE equations ((ETPT-ETEC) < 170 mm). Analysis of applied water and precipitation, soil moisture, leaf stomatal resistance, and canopy cover suggest that the lower observed ETEC was not the result of water stress or reduced vegetation cover. Use of a custom-calibrated bulk canopy resistance improved the reference ET estimate and reduced seasonal ET discrepancy relative to ETPT and ETEC in the less windy field and had mixed performance in the windier field. These divergences suggest that modifications to reference ET equations may be warranted in some tropical regions.

  14. Using the Priestley-Taylor expression for estimating actual evapotranspiration from satellite Landsat ETM + data

    NASA Astrophysics Data System (ADS)

    Khaldi, A.; Khaldi, A.; Hamimed, A.

    2014-09-01

    The quantification of evapotranspiration from irrigated areas is important for agriculture water management, especially in arid and semi-arid regions where water deficiency is becoming a major constraint in economic welfare and sustainable development. Conventional methods that use point measurements to estimate evapotranspiration are representative only of local areas and cannot be extended to large areas because of landscape heterogeneity. Remote sensing-based energy balance models are presently most suited for estimating evapotranspiration at both field and regional scales. In this study, we aim to develop a methodology based on the triangle concept, allowing estimation of evapotranspiration through the classical equation of Priestley and Taylor (1972) where the proportional coefficient α in this equation is ranged using a linear interpolation between surface temperature and Normalized Difference Vegetation Index (NDVI) values. Preliminary results using remotely sensed data sets from Landsat ETM+ over the Habra Plains in west Algeria are in good agreement with ground measurements. The proposed approach appears to be more reliable and easily applicable for operational estimation of evapotranspiration over large areas.

  15. Spatio-temporal Characteristics of Actual Evapotranspiration Trends in sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Marshall, M. T.; Funk, C. C.; Michaelsen, J.

    2010-12-01

    Actual evapotranspiration (AET) is an important moisture flux linking the Earth’s surface to the atmospheric hydrologic cycle. Global warming is expected to intensify this cycle, leading to moisture deficits over the sub-tropics, which will influence climate at higher latitudes. The spatio-temporal characterization of tropical AET is critical to understanding regional and global climate. To date, many studies on the temporal characteristics of AET across sub-Saharan Africa have employed vegetation-based indices derived from satellite imagery. Although these studies implicitly reflect trends in AET, they quantify the magnitude of change. In this study, we used the latest developments in remote sensing and land-surface modeling to characterize the magnitude and timing of AET in sub-Saharan Africa. We considered several models were evaluated from 1981-2000 using monthly discharge and precipitation from ten sub-basins representative of hydrology in sub-Saharan Africa. Discharge data was provided by the Global Runoff Data Centre, while precipitation data was comprised of ECMWF, NCAR, NOAA/GDAS, and CMAP reanalysis fields synthesized in the Global Land Data Assimilation System (GLDAS). The AET models included the Community Land Model, Variable Infiltration Capacity (VIC) model, Noah, and two hybrids that we developed driven by a dynamic vegetation component defined in Fisher et al. 2008. The dynamic canopy components in our hybrid models were driven by the LTDR AVHRR daily corrected reflectance data over the evaluation period. The evaluation revealed that VIC was superior to the other models in capturing the magnitude and variability of runoff in the sub-basins. A trend analysis was then performed on VIC AET from 1979-2009 using standard parametric and non-parametric techniques. Linear and median trend analysis was performed on seasonal and annual AET totals to measure the magnitude of change. The analysis revealed several alarming patterns, including large and

  16. Evaluation of a Modified SEBAL Algorithm to Estimate Actual Evapotranspiration in Cotton Ecosystems of Central Asia using Microwave and Optical Remote Sensing Data

    NASA Astrophysics Data System (ADS)

    Knoefel, Patrick; Conrad, Christopher

    2015-04-01

    Being recognized as an essential component of both the water and the energy cycle, actual evapotranspiration (ETa) plays in important role in order to describe the complex interactions within the climate system of the Earth. Here, remote sensing is a powerful tool to estimate regional ETa to support the regional water management. For instance, the water withdrawal of the agricultural sector in OECD countries is on average about 44 %, but in the states of Central Asia it achieves more than 90 %. This fact is identified as one of the main reasons for the increasing water scarcity in this region. An accuracy assessment of the methods used for determining ETa is necessary concerning an appropriate use of the model results to support agriculture and irrigation management. Within Central Asia the Khorezm region in Uzbekistan is a case study region for the problems of irrigated agriculture. For Khorezm the seasonal ETa based on MODIS data was calculated for the years 2009 - 2011 using a partly modified surface energy balance algorithm for land (SEBAL). SEBAL was implemented based on MODIS time series to calculate the energy balance components like net radiation (Rn), sensible heat (H), latent heat (LE), and soil heat flux (G). Whilst SEBAL is using an empirical equation for the estimation of G, a more physically based method was introduced in this study. This method uses microwave soil moisture products (ASAR and ASCAT-SSM) as an additional model input. The input parameters and the model results of all energy balance components (Rn, H, LE, and G) were intensively validated by field measurements with an eddy covariance system and soil sensors. The model shows very good performance for Rn with average model efficiency (NSE) of 0.68 and small relative errors (rRMSE) of about 10%. For turbulent heat fluxes good results can be achieved with NSE of 0.31 for H and 0.55 for LE, the rRMSE are about 21% (H) and 18% (LE). Soil heat flux estimation could be improved using the

  17. Actual evapotranspiration estimation by means of airborne and satellite remote sensing data

    NASA Astrophysics Data System (ADS)

    Ciraolo, Giuseppe; D'Urso, Guido; Minacapilli, Mario

    2006-09-01

    During the last the two decades, the scientific community developed detailed mathematical models for simulating land surface energy fluxes and crop evapotranspiration rates by means of a energy balance approach. These models can be applied in large areas and with a spatial distributed approach using surface brightness temperature and some ancillary data retrieved from satellite/airborne remote sensed imagery. In this paper a district scale application in combination with multispectral (LandaSat 7 TM data) and hyperspectral airborne MIVIS data has been carried out to test the potentialities of two different energy balance models to estimate evapotranspiration fluxes from a set of typical Mediterranean crops (wine, olive, citrus). The impact of different spatial and radiometric resolutions of MIVIS (3m x 3m) and LandSat (60m x 60m) on models-derived fluxes has been investigated to understand the roles and the main conceptual differences between the two models which respectively use a "single-layer" (SEBAL) and a "two-layer" (TS) schematisation.

  18. Alternative methods to predict actual evapotranspiration illustrate the importance of accounting for phenology - Part 2: The event driven phenology model

    NASA Astrophysics Data System (ADS)

    Kovalskyy, V.; Henebry, G. M.

    2011-05-01

    Evapotranspiration (ET) flux constitutes a major component of both the water and energy balances at the land surface. Among the many factors that control evapotranspiration, phenology poses a major source of uncertainty in attempts to predict ET. Contemporary approaches to ET modeling and monitoring frequently summarize the complexity of the seasonal development of vegetation cover into static phenological trajectories (or climatologies) that lack sensitivity to changing environmental conditions. The Event Driven Phenology Model (EDPM) offers an alternative, interactive approach to representing phenology. This study presents the results of an experiment designed to illustrate the differences in ET arising from various techniques used to mimic phenology in models of land surface processes. The experiment compares and contrasts two realizations of static phenologies derived from long-term satellite observations of the Normalized Difference Vegetation Index (NDVI) against canopy trajectories produced by the interactive EDPM trained on flux tower observations. The assessment was carried out through validation of predicted ET against records collected by flux tower instruments. The VegET model (Senay, 2008) was used as a framework to estimate daily actual evapotranspiration and supplied with seasonal canopy trajectories produced by the EDPM and traditional techniques. The interactive approach presented the following advantages over phenology modeled with static climatologies: (a) lower prediction bias in crops; (b) smaller root mean square error in daily ET - 0.5 mm per day on average; (c) stable level of errors throughout the season similar among different land cover types and locations; and (d) better estimation of season duration and total seasonal ET.

  19. Alternative methods to predict actual evapotranspiration illustrate the importance of accounting for phenology - Part 2: The event driven phenology model

    NASA Astrophysics Data System (ADS)

    Kovalskyy, V.; Henebry, G. M.

    2012-01-01

    Evapotranspiration (ET) flux constitutes a major component of both the water and energy balances at the land surface. Among the many factors that control evapotranspiration, phenology poses a major source of uncertainty in attempts to predict ET. Contemporary approaches to ET modeling and monitoring frequently summarize the complexity of the seasonal development of vegetation cover into static phenological trajectories (or climatologies) that lack sensitivity to changing environmental conditions. The Event Driven Phenology Model (EDPM) offers an alternative, interactive approach to representing phenology. This study presents the results of an experiment designed to illustrate the differences in ET arising from various techniques used to mimic phenology in models of land surface processes. The experiment compares and contrasts two realizations of static phenologies derived from long-term satellite observations of the Normalized Difference Vegetation Index (NDVI) against canopy trajectories produced by the interactive EDPM trained on flux tower observations. The assessment was carried out through validation of predicted ET against records collected by flux tower instruments. The VegET model (Senay, 2008) was used as a framework to estimate daily actual evapotranspiration and supplied with seasonal canopy trajectories produced by the EDPM and traditional techniques. The interactive approach presented the following advantages over phenology modeled with static climatologies: (a) lower prediction bias in crops; (b) smaller root mean square error in daily ET - 0.5 mm per day on average; (c) stable level of errors throughout the season similar among different land cover types and locations; and (d) better estimation of season duration and total seasonal ET.

  20. Potential of remote sensing derived soil moisture for the estimation of actual evapotranspiration in cotton ecosystems of Middle Asia

    NASA Astrophysics Data System (ADS)

    Knoefel, Patrick; Conrad, Christopher; Dech, Stefan

    2013-04-01

    Actual evapotranspiration (ETact) is an essential component of the water balance and its determination for larger areas is difficult on regional scale. Here, remote sensing provides a powerful tool to estimate regional actual evapotranspiration to support regional water management. Particularly, in irrigation agriculture of Middle Asia decision makers have to handle limited water availability and to improve the efficiency of their regional water management systems. The growing interest in quantifying regional actual ET for water resource and irrigation management led to the development of numerous methods to estimate ET from remote sensing data. The study is primarily concerned with the irrigation farming of cotton ecosystems in Middle Asia, in particular with the situation within Khorezm Oblast in Uzbekistan. Regional problems of Khorezm Oblast are e.g. high groundwater levels, soil salinity, and non-sustainable use of land and water. The water for irrigation is taken from the Amu Darya River and then canalled to the agricultural fields. The available water in Khorezm depends on the water demand in the upstream regions. Because of this variation and the historical annual shortage of available irrigation water a sustainable use of water is highly important for the regional water management in Khorezm. Cotton is the major crop in Khorezm region. About 46% of the agricultural area was covered with cotton in 2010 and 2011, among the other main crops winter wheat (30%) and rice (5%). The objective of this study was to investigate the potential of satellite derived surface soil moisture for the optimization of the estimated ETact. Actual evapotranspiration in this study is indirectly derived by solving the surface energy balance equation using the surface energy balance algorithm for land (SEBAL). Due to its high temporal resolution MODIS (1km) data is used to provide the input information to solve the equation. The results were compared with measurements of an eddy

  1. Evaluating the performance of reference evapotranspiration equations with scintillometer measurements under Mediterranean climate and effects on olive grove actual evapotranspiration estimated with FAO-56 water balance model

    NASA Astrophysics Data System (ADS)

    Minacapilli, Mario; Cammalleri, Carmelo; Ciraolo, Giuseppe; Provenzano, Giuseppe; Rallo, Giovanni

    2014-05-01

    The concept of reference evapotranspiration (ETo) is widely used to support water resource management in agriculture and for irrigation scheduling, especially under arid and semi-arid conditions. The Penman-Monteith standardized formulations, as suggested by ASCE and FAO-56 papers, are generally applied for accurate estimations of ETo, at hourly and daily scale. When detailed meteorological information are not available, several alternative and simplified equations, using a limited number of variables, have been proposed (Blaney-Criddle, Hargreaves-Samani, Turc, Makkinen and Pristley-Taylor). In this paper, scintillometer measurements collected for six month in 2005, on an experimental plot under "reference" conditions, were used to validate different ETo equations at hourly and daily scale. Experimental plot is located in a typical agricultural Mediterranean environment (Sicily, Italy), where olive groves is the dominant crop. As proved by other researches, the comparison confirmed the best agreement between estimated and measured fluxes corresponds to FAO-56 Penman-Monteith standardized equation, that was characterized by both the lowest average error and the minimum bias. However, the analysis also evidenced a quite good performance of Pristley-Taylor equation, that can be considered as a valid alternative to the more sophisticated Penman-Monteith method. The different ETo series, obtained by the considered simplified equations, were then used as input in the FAO-56 water balance model, in order to evaluate, for olive groves, the errors on estimated actual evapotranspiration ET. To this aim soil and crop model input parameters were settled by considering previous experimental researches already used to calibrate and validate the FAO-56 water balance model on olive groves, for the same study area. Also in this case, assuming as the true values of ET those obtained using the water balance coupled with Penman-Monteith ETo input values, the Priestley-Taylor equation

  2. Evaluation of a Modified Priestly-Taylor Model for Actual Evapotranspiration in sub- Saharan Africa

    NASA Astrophysics Data System (ADS)

    Marshall, M. T.; Michaelsen, J.; Funk, C.; Artan, G.

    2008-12-01

    Climate change and the intensification of the water cycle is an important field of study, as global warming is expected to lead to dramatic increases in the frequency and magnitude of storms, floods, and droughts worldwide. In sub-tropical Africa, it is expected that the increase in evaporation and subsequent decrease in surface runoff will increase water demand in an already climate sensitive region. Studies also show that modeled soil moisture, a surrogate for evapotranspiration (ET), can improve rainfall and streamflow forecasts in these areas. Our objective, here therefore, is to evaluate a new ET model (Fisher et al., 2008) at inter- seasonal catchment scales. The Fisher et al. (2008) model uses functional eco-physiological relationships to adjust the Priestly-Taylor formulation of potential ET. It has performed well against several flux towers at tropical, sub-tropical, and temperate latitudes (R2=0.90). Although the model was extrapolated using remote sensing and climate reanalysis data, the validation was performed using site specific monthly average net radiation (Rn), monthly surface vapor pressure, and maximum monthly surface temperature. Two additional inputs are required for the model that can be acquired from remote sensing: the monthly average normalized difference vegetation index and soil-adjusted vegetation index. The vegetation indices will be calculated from a new atmospherically corrected AVHRR dataset of global daily reflectance at 0.05° resolution (NASA Land Long Term Data Record). The climate variables will be extracted from the bias-corrected European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis dataset at 0.05° resolution. The model will be evaluated at a seasonal timestep from 1981-1999 using cumulative runoff and lagged precipitation for seven major catchments in sub-Saharan Africa. It is expected that the highest model performance will be in areas where Rn is the dominant control on ET and advection is relatively small

  3. Evaluation of SEBS for estimation of actual evapotranspiration using ASTER satellite data for irrigation areas of Australia

    NASA Astrophysics Data System (ADS)

    Ma, Weiqiang; Hafeez, Mohsin; Ishikawa, Hirohiko; Ma, Yaoming

    2013-05-01

    Spatial knowledge of land surface evapotranspiration (ET) is of prime interest for environmental applications, such as optimizing irrigation water use, irrigation system performance, crop water deficit, drought mitigation strategies, and accurate initialization of climate prediction models especially in arid and semiarid catchments where water shortage is a critical problem. The recent drought in Australia and concerns about climate change have highlighted the need to manage water resources more sustainably especially in the Murrumbidgee catchment which utilizes bulk water for food production. This study deals with the application of a Surface Energy Balance System (SEBS) algorithm based on Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) data and field observations has been proposed and tested for deriving ET over Coleambally Irrigation Area, located in the southwest of NSW, Australia. We have used 12 ASTER scenes covering the time period of 2002, 2003, 2004, 2005, 2006, and 2009 for estimating the actual ET over the study area. To validate the proposed methodology, the ground-measured ET was compared to the ASTER-derived actual ET values for the study area. The derived ET value over the study area is much closer to the field measurement. From the remote sensing results and observations, the root mean square error is 0.89 and the mean absolute percentage difference is 2.87 %, which demonstrate the reasonability of SEBS ET estimation for the study area.

  4. Actual evapotranspiration for a reference crop within measured and future changing climate periods in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Katerji, Nader; Rana, Gianfranco; Ferrara, Rossana Monica

    2016-05-01

    The study compares two formulas for calculating the daily evapotranspiration ET0 for a reference crop. The first formula was proposed by Allen et al. (AL), while the second one was proposed by Katerji and Perrier with the addition of the carbon dioxide (CO2) effect on evapotranspiration (KP). The study analyses the impact of the calculation by the two formulas on the irrigation requirement (IR). Both formulas are based on the Penman-Monteith equation but adopt different approaches for parameterising the canopy resistance r c . In the AL formula, r c is assumed constant and not sensitive to climate change, whereas in the KP formula, r c is first parameterised as a function of climatic variables, then ET0 is corrected for the air CO2 concentration. The two formulas were compared in two periods. The first period involves data from two sites in the Mediterranean region within a measured climate change period (1981-2006) when all the input climatic variables were measured. The second period (2070-2100) involves data from a future climate change period at one site when the input climatic variables were forecasted for two future climate scenarios (A2 and B2). The annual cumulated values of ET0 calculated by the AL formula are systematically lower than those determined by the KP formula. The differences between the ET0 estimation with the AL and KP formulas have a strong impact on the determination of the IR for the reference crop. In fact, for the two periods, the annual values of IR when ET0 is calculated by the AL formula are systematically lower than those calculated by the KP formula. For the actual measured climate change period, this reduction varied from 26 to 28 %, while for the future climate change period, it varied based on the scenario from 16 % (A2) to 20 % (B2).

  5. Surface energy balance and actual evapotranspiration of the transboundary Indus Basin estimated from satellite measurements and the ETLook model

    NASA Astrophysics Data System (ADS)

    Bastiaanssen, W. G. M.; Cheema, M. J. M.; Immerzeel, W. W.; Miltenburg, I. J.; Pelgrum, H.

    2012-11-01

    The surface energy fluxes and related evapotranspiration processes across the Indus Basin were estimated for the hydrological year 2007 using satellite measurements. The new ETLook remote sensing model (version 1) infers information on actual Evaporation (E) and actual Transpiration (T) from combined optical and passive microwave sensors, which can observe the land-surface even under persistent overcast conditions. A two-layer Penman-Monteith equation was applied for quantifying soil and canopy evaporation. The novelty of the paper is the computation of E and T across a vast area (116.2 million ha) by using public domain microwave data that can be applied under all weather conditions, and for which no advanced input data are required. The average net radiation for the basin was estimated as being 112 Wm-2. The basin average sensible, latent and soil heat fluxes were estimated to be 80, 32, and 0 Wm-2, respectively. The average evapotranspiration (ET) and evaporative fraction were 1.2 mm d-1 and 0.28, respectively. The basin wide ET was 496 ± 16.8 km3 yr-1. Monte Carlo analysis have indicated 3.4% error at 95% confidence interval for a dominant land use class. Results compared well with previously conducted soil moisture, lysimeter and Bowen ratio measurements at field scale (R2 = 0.70; RMSE = 0.45 mm d-1; RE = -11.5% for annual ET). ET results were also compared against earlier remote sensing and modeling studies for various regions and provinces in Pakistan (R2 = 0.76; RMSE = 0.29 mmd-1; RE = 6.5% for annual ET). The water balance for all irrigated areas together as one total system in Pakistan and India (26.02 million ha) show a total ET value that is congruent with the ET value from the ETLook surface energy balance computations. An unpublished validation of the same ETLook model for 23 jurisdictional areas covering the entire Australian continent showed satisfactory results given the quality of the watershed data and the diverging physiographic and climatic

  6. Drivers of actual evapotranspiration and runoff in East Africa during the mid-Holocene: assessments from an ecosystem model

    NASA Astrophysics Data System (ADS)

    Fer, Istem; Jeltsch, Florian; Tietjen, Britta; Trauth, Martin

    2014-05-01

    Understanding the evolution and response of the hydrological cycle under changing climate is of vital importance for human populations all around the world. Especially so in regions like East Africa, where society largely depends on the availability of water and the hydrologic conditions are highly sensitive to changes in the distribution and amount of precipitation. In this endeavor, studying past hydrological changes provides us realistic scenarios and data to better understand and predict the extent of the future hydrological changes. However while studying the past, paleovegetation, which plays a pivotal role in the paleo-hydrological cycle, is difficult to determine from fossil pollen records as pollen data can provide very limited information on spatial distribution and composition of the vegetation cover. Here ecosystem models driven by paleo-climate conditions can provide spatially-extensive information on the coupled dynamics of past vegetation and hydrological measures such as actual evapotranspiration (AET), potential evapotranspiration (PET) and runoff. In this study, we looked at AET and runoff estimates of an ecosystem model as these are important elements of water transfer in the hydrological cycle and critical for water balance calculations. We applied the ecosystem model, LPJ-GUESS, for present-day with data from Climatic Research Unit CRU TS3.20 climate dataset, and for mid-Holocene (6 kyrs BP) with data from an atmosphere-ocean coupled global climate model EC-Earth. Climate data for both periods were downscaled to a 10 arc min resolution in order to better resolve the impacts of the complex topography on vegetation distribution, AET and runoff. Comparison of the simulated AET and runoff values for East Africa, show similar patterns as annual AET estimates for the period 1961-1990 by Food and Agriculture Organization of the United Nations (FAO), and with the observed runoff data from Cogley (1998), respectively. Comparison of simulated present

  7. Validation of an improved energy balance model to estimate actual evapotranspiration in irrigated cotton ecosystems of Central Asia

    NASA Astrophysics Data System (ADS)

    Knoefel, Patrick; Conrad, Christopher; Falk, Ulrike; Bauer-Marschallinger, Bernhard

    2014-05-01

    The understanding of the hydrological and the energy cycles are essential in order to describe the complex interactions within the climate system of the earth. Being recognized as an essential component of both the water and the energy cycle, reliable estimation of actual evapotranspiration and its spatial distribution is one outstanding challenge in this context. For instance, in irrigation systems of arid regions, artificial locations of evapotranspiration have been created. An in-depth process understanding is of paramount importance, as irrigated agriculture consumes about 70 % of the available freshwater resources worldwide, with a significant but unsatisfyingly quantified impact on the water cycle, especially on regional scale. Moreover, an exact quantification of ET inside these artificial ecosystems enables assessments of crop water consumptions and hence about water use efficiency (WUE). The withdrawal of water for agricultural use in the countries of Central Asia is more than 90%. Khorezm region in Uzbekistan is a case study region for the problems of irrigated agriculture in CA. For Khorezm the seasonal actual ET was calculated for the years 2003 - 2010 using the partly modified surface energy balance algorithm for land (SEBAL). SEBAL was implemented based on MODIS time series to calculate the energy balance components like net radiation (Rn), sensible heat (H), latent heat (LE), and soil heat flux (G). Whilst SEBAL is using an empirical equation for estimating G, a more physically based method was introduced in this study. This method uses microwave soil moisture products (ASAR-SSM and ASCAT-SSM) as additional input information. The modelled energy balance components were intensively validated by field measurements with an eddy covariance system and soil sensors. For turbulent heat fluxes the RMSE is about 40 W/m² for H and 80 W/m² for LE with a coefficient of determination (r²) of 0.64 for H and 0.52 for LE. Soil heat flux estimation could be

  8. A critical analysis of three remote sensing-based actual evapotranspiration assessment methods over sparse crops agricultural areas

    NASA Astrophysics Data System (ADS)

    Cammalleri, Carmelo; Ciraolo, Giuseppe; La Loggia, Goffredo; Minacapilli, Mario

    2010-10-01

    During last two decades the increasing availability of remotely sensed acquisitions in the thermal infrared part of the spectrum has encouraged hydrologist community to develop models and methodologies based on these kind of data. The aim of this paper is to compare three methods developed to assess the actual evapotranspiration spatial distribution by means of remote sensing data. The comparison was focused on the differences between the "single" (SEBAL) and "two" source (TSEB) surface energy balance approaches and the S-SEBI semi-empirical method. The first assumes a semiempirical internal calibration for the sensible heat flux assessment; the second uses a physically based approach in order to assess separately the soil and vegetation fluxes. Finally, the last one is based on the correlation between albedo and surface temperature for evaporative fraction estimations. The models were applied using 7 high resolution images, collected by an airborne platform between June and October 2008, approximately every 3 weeks. The acquired data include multi-spectral images (red, green and near infrared) and thermal infrared images for surface temperature estimation. The study area, located in the south-west cost of Sicily, Italy), is characterised by the presence of typical Mediterranean cultivations: olive, vineyard and citrus. Due to irrigation supplies and rainfall events, the water availability for the crops varies in time and this allowed to perform the comparison in a wide range of the modelled variables. Additionally, the availability of high spatial resolution images allowed the testing of the models performances at field scale despite the high vegetation fragmentation of the study area. The comparison of models performance highlights a good agreements of model estimations, analyzed by means of MAD (Mean Absolute Differences) and MAPD (Mean Absolute Percent Differences) indices, especially in terms of study area averaged fluxes. The analysis in correspondence of

  9. Utility of Penman-Monteith, Priestley-Taylor, reference evapotranspiration, and pan evaporation methods to estimate pasture evapotranspiration

    USGS Publications Warehouse

    Sumner, D.M.; Jacobs, J.M.

    2005-01-01

    Actual evapotranspiration (ETa) was measured at 30-min resolution over a 19-month period (September 28, 2000-April 23, 2002) from a nonirrigated pasture site in Florida, USA, using eddy correlation methods. The relative magnitude of measured ETa (about 66% of long-term annual precipitation at the study site) indicates the importance of accurate ET a estimates for water resources planning. The time and cost associated with direct measurements of ETa and the rarity of historical measurements of ETa make the use of methods relying on more easily obtainable data desirable. Several such methods (Penman-Monteith (PM), modified Priestley-Taylor (PT), reference evapotranspiration (ET 0), and pan evaporation (Ep)) were related to measured ETa using regression methods to estimate PM bulk surface conductance, PT ??, ET0 vegetation coefficient, and Ep pan coefficient. The PT method, where the PT ?? is a function of green-leaf area index (LAI) and solar radiation, provided the best relation with ET a (standard error (SE) for daily ETa of 0.11 mm). The PM method, in which the bulk surface conductance was a function of net radiation and vapor-pressure deficit, was slightly less effective (SE=0.15 mm) than the PT method. Vegetation coefficients for the ET0 method (SE=0.29 mm) were found to be a simple function of LAI. Pan coefficients for the Ep method (SE=0.40 mm) were found to be a function of LAI and Ep. Historical or future meteorological, LAI, and pan evaporation data from the study site could be used, along with the relations developed within this study, to provide estimates of ETa in the absence of direct measurements of ETa. Additionally, relations among PM, PT, and ET0 methods and ETa can provide estimates of ETa in other, environmentally similar, pasture settings for which meteorological and LAI data can be obtained or estimated. ?? 2004 Elsevier B.V. All rights reserved.

  10. Global patterns of annual actual evapotranspiration with land-cover type: knowledge gained from a new observation-based database

    NASA Astrophysics Data System (ADS)

    Ambrose, S. M.; Sterling, S. M.

    2014-10-01

    The process of evapotranspiration (ET) plays a critical role in the earth system, driving key land-surface processes in the energy, water and carbon cycles. Land-cover (LC) exerts multiple controls on ET, yet the global distribution of ET by LC and the related physical variables are poorly understood. The lack of quantitative understanding of global ET variation with LC begets considerable uncertainties regarding how ET and key land-surface processes will change alongside ongoing anthropogenic LC transformations. Here we apply statistical analysis and models to a new global ET database to advance our understanding of how annual actual ET varies with LC type. We derive global fields for each LC using linear mixed effect models (LMMs) that use geographical and meteorological variables as possible independent regression variables. Our inventory of ET observations reveals important gaps in spatial coverage that overlie hotpots of global change. There is a spatial bias of observations towards the mid latitudes, and LCs with large areas in the high latitudes (lakes, wetlands and barren land) are poorly represented. From the distribution of points as well as the uncertainty analysis completed by bootstrapping we identify high priority regions in need of more data collection. Our analysis of the new database provides new insights into how ET varies globally, providing more robust estimates of global ET rates for a broad range of LC types. Results reveal that different LC types have distinct global patterns of ET. Furthermore, zonal ET means among LCs reveal new patterns: ET rates in low latitudinal bands are more sensitive to LC change than in higher latitude bands; LCs with a higher evaporation component show higher variability of ET at the global scale; and LCs with dispersed rather than contiguous global locations have a higher variability of ET at the global scale. Results from this study indicate two major advancements are required to improve our ability to predict

  11. Fully-automated estimation of actual to potential evapotranspiration in the Everglades using Landsat and air temperature data as inputs to the Vegetation Index-Temperature Trapezoid method

    NASA Astrophysics Data System (ADS)

    Yagci, A. L.; Jones, J. W.

    2014-12-01

    While the greater Everglades contains a vast wetland, evapotranspiration (ET) is a major source of water "loss" from the system. Like other ecosystems, the Everglades is vulnerable to drought. Everglades restoration science and resource management requires information on the spatial and temporal distribution of ET. We developed a fully-automated ET model using the Vegetation Index-Temperature Trapezoid concept. The model was tested and evaluated against in-situ ET observations collected at the Shark River Slough Mangrove Forest eddy-covariance tower in Everglades National Park (Sitename / FLUXNET ID: Florida Everglades Shark River Slough Mangrove Forest / US-Skr). It uses Landsat Surface Reflectance Climate Data from Landsat 5, and Landsat 5 thermal and air temperature data from the Daily Gridded Surface Dataset to output the ratio of actual evapotranspiration (AET) and potential evapotranspiration (PET). When multiplied with a PET estimate, this output can be used to estimate ET at high spatial resolution. Furthermore, it can be used to downscale coarse resolution ET and PET products. Two example outputs covering the agricultural lands north of the major Everglades wetlands extracted from two different dates are shown below along with a National Land Cover Database image from 2011. The irrigated and non-irrigated farms are easily distinguishable from the background (i.e., natural land covers). Open water retained the highest AET/PET ratio. Wetlands had a higher AET/PET ratio than farmlands. The main challenge in this study area is prolonged cloudiness during the growing season.

  12. Evapotranspiration Modeling and Measurements at Ecosystem Level

    NASA Astrophysics Data System (ADS)

    Sirca, C.; Snyder, R. L.; Mereu, S.; Kovács-Láng, E.; Ónodi, G.; Spano, D.

    2012-12-01

    In recent years, the availability of reference evapotranspiration (ETo) data is greatly increased. ETo, in conjunction with coefficients accounting for the difference between the vegetation and the reference surface, provides estimation of the actual evapotranspiration (ETa). The coefficients approach was applied in the past mainly for crops, due the lack of experimental data and difficulties to account for terrain and vegetation variability in natural ecosystems. Moreover, the assessment of ETa over large spatial scale by measurements is often time consuming, and requires several measurement points with relatively expensive and sophisticated instrumentation and techniques (e.g. eddy covariance). The Ecosystem Water Program (ECOWAT) was recently developed to help estimates of ETa of ecosystems by accounting for microclimate, vegetation type, plant density, and water stress. ETa on natural and semi-natural ecosystems has several applications, e.g. water status assessment, fire danger estimation, and ecosystem management practices. In this work, results obtained using ECOWAT to assess ETa of a forest ecosystem located in Hungary are reported. The site is a part of the EU-FP7 INCREASE project, which aims to study the effects of climate change on European shrubland ecosystems. In the site, a climate manipulation experiment was setted up to have a warming and a drought treatment (besides the control). Each treatment was replicated three times We show how the ECOWAT model performed when the predicted actual evapotranspiration is compared with actual evapotranspiration obtained from Surface Renewal method and with soil moisture measurements. ECOWAT was able to capture the differences in the water balance at treatment level, confirming its potential as a tool for water status assessment. For the Surface Renewal method, high frequency temperature data were collected to estimate the sensible heat flux (H'). The net radiation (Rn) and soil heat flux density (G) were also

  13. Testing an Energy Balance Model for Estimating Actual Evapotranspiration Using Remotely Sensed Data. [Hannover, West Germany barley and wheat fields

    NASA Technical Reports Server (NTRS)

    Gurney, R. J.; Camillo, P. J.

    1985-01-01

    An energy-balance model is used to estimate daily evapotranspiration for 3 days for a barley field and a wheat field near Hannover, Federal Republic of Germany. The model was calibrated using once-daily estimates of surface temperatures, which may be remotely sensed. The evaporation estimates were within the 95% error bounds of independent eddy correlation estimates for the daytime periods for all three days for both sites, but the energy-balance estimates are generally higher; it is unclear which estimate is biassed. Soil moisture in the top 2 cm of soil, which may be remotely sensed, may be used to improve these evaporation estimates under partial ground cover. Sensitivity studies indicate the amount of ground data required is not excessive.

  14. Estimating long-term changes in actual evapotranspiration and water storage using a one-parameter model

    NASA Astrophysics Data System (ADS)

    Sharma, Asha N.; Walter, M. Todd

    2014-11-01

    Estimations of long-term regional trends in evapotranspiration (E) and water storage are key to our understanding of hydrology in a changing environment. Yet they are difficult to make due to the lack of long-term measurements of these quantities. Here we use a simple one-parameter model in conjunction with Gravity Recovery and Climate Experiment (GRACE) data to estimate long-term E and storage trends in the Missouri River Basin. We find that E has increased in the river basin over the period 1929-2012, consistent with other studies that have suggested increases in E with a warming climate. The increase in E appears to be driven by an increase in precipitation and water storage because potential E has not changed substantially. The simplicity of the method and its minimal data requirements provide a transparent approach to assessing long-term changes in hydrological fluxes and storages, and may be applicable to regions where meteorological and hydrological data are scarce.

  15. Water balance-based actual evapotranspiration reconstruction from ground and satellite observations over the conterminous United States

    NASA Astrophysics Data System (ADS)

    Wan, Zhanming; Zhang, Ke; Xue, Xianwu; Hong, Zhen; Hong, Yang; Gourley, Jonathan J.

    2015-08-01

    The objective of this study is to produce an observationally based monthly evapotranspiration (ET) product using the simple water balance equation across the conterminous United States (CONUS). We adopted the best quality ground and satellite-based observations of the water budget components, i.e., precipitation, runoff, and water storage change, while ET is computed as the residual. Precipitation data are provided by the bias-corrected PRISM observation-based precipitation data set, while runoff comes from observed monthly streamflow values at 592 USGS stream gauging stations that have been screened by strict quality controls. We developed a land surface model-based downscaling approach to disaggregate the monthly GRACE equivalent water thickness data to daily, 0.125° values. The derived ET computed as the residual from the water balance equation is evaluated against three sets of existing ET products. The similar spatial patterns and small differences between the reconstructed ET in this study and the other three products show the reliability of the observationally based approach. The new ET product and the disaggregated GRACE data provide a unique, important hydro-meteorological data set that can be used to evaluate the other ET products as a benchmark data set, assess recent hydrological and climatological changes, and terrestrial water and energy cycle dynamics across the CONUS. These products will also be valuable for studies and applications in drought assessment, water resources management, and climate change evaluation.

  16. A coupled remote sensing and the Surface Energy Balance based algorithms to estimate actual evapotranspiration over the western and southern regions of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Mahmoud, Shereif H.; Alazba, A. A.

    2016-07-01

    In countries with absolute water scarcity such as the Kingdom of Saudi Arabia (KSA), large-scale actual evapotranspiration estimation is of great concern in water use practices. Herein, spatial and temporal distribution of actual evapotranspiration (AET) in the western and southern regions of KSA during 1992-2014 was estimated using the SEBAL model with field observations. Zonal statistics for each land use-cover type were also identified, in order to understand their effects on water consumption. In addition, daily and seasonal water consumption for major crops was computed. Results revealed a gradual increase in monthly AET values from January to April and subsequent decline from May to December. The maximum monthly AET values were observed for irrigated cropland in southwestern, central, and southeastern regions of Asir Province, central and southwestern regions of Al-Baha Province, central and the plains region of Jazan Province, southern portion of Makkah Province, and limited areas in the northern regions of Madinah Province. The annual AET ranged from 418.8 to 3442.3 mm yr-1. The normal distribution of mean annual AET values ranged from 717 to 1020 mm yr-1. Forty-two percent of the study area had an annual AET that ranged from 717 to 1020 mm yr-1. The second highest range of frequencies was concentrated around 1020-1322 mm yr-1, representing the majority of agricultural land. The consumptive water use of the different land cover types in study area indicated that irrigated cropland which occupied 14.6% of the study area had AET rates much higher than other land uses. Water bodies are the next highest, with forest and shrubland and sparse vegetation slightly lower, and very low AET rates from bare soil. Daily and seasonal water consumption of major cropping systems varied spatially depending on cropping practices and climatic conditions.

  17. Determination of actual crop evapotranspiration (ETc) and dual crop coefficients (Kc) for cotton, wheat and maize in Fergana Valley: integration of the FAO-56 approach and BUDGET

    NASA Astrophysics Data System (ADS)

    Kenjabaev, Shavkat; Dernedde, Yvonne; Frede, Hans-Georg; Stulina, Galina

    2014-05-01

    Determination of the actual crop evapotranspiration (ETc) during the growing period is important for accurate irrigation scheduling in arid and semi-arid regions. Development of a crop coefficient (Kc) can enhance ETc estimations in relation to specific crop phenological development. This research was conducted to determine daily and growth-stage-specific Kc and ETc values for cotton (Gossypium hirsutum L.), winter wheat (Triticum aestivum L.) and maize (Zea mays L.) for silage at fields in Fergana Valley (Uzbekistan). The soil water balance model - Budget with integration of the dual crop procedure of the FAO-56 was used to estimate the ETc and separate it into evaporation (Ec) and transpiration (Tc) components. An empirical equation was developed to determine the daily Kc values based on the estimated Ec and Tc. The ETc, Kc determination and comparison to existing FAO Kc values were performed based on 10, 5 and 6 study cases for cotton, wheat and maize, respectively. Mean seasonal amounts of crop water consumption in terms of ETc were 560±50, 509±27 and 243±39 mm for cotton, wheat and maize, respectively. The growth-stage-specific Kc for cotton, wheat and maize was 0.15, 0.27 and 0.11 at initial; 1.15, 1.03 and 0.56 at mid; and 0.45, 0.89 and 0.53 at late season stages. These values correspond to those reported by the FAO-56. Development of site specific Kc helps tremendously in irrigation management and furthermore provides precise water applications in the region. The developed simple approach to estimate daily Kc for the three main crops grown in the Fergana region was a first attempt to meet this issue. Keywords: Actual crop evapotranspiration, evaporation and transpiration, crop coefficient, model BUDGET, Fergana Valley.

  18. A coupled remote sensing and the Surface Energy Balance with Topography Algorithm (SEBTA) to estimate actual evapotranspiration under complex terrain

    NASA Astrophysics Data System (ADS)

    Gao, Z. Q.; Liu, C. S.; Gao, W.; Chang, N. B.

    2010-07-01

    Evapotranspiration (ET) may be used as an ecological indicator to address the ecosystem complexity. The accurate measurement of ET is of great significance for studying environmental sustainability, global climate changes, and biodiversity. Remote sensing technologies are capable of monitoring both energy and water fluxes on the surface of the Earth. With this advancement, existing models, such as SEBAL, S_SEBI and SEBS, enable us to estimate the regional ET with limited temporal and spatial scales. This paper extends the existing modeling efforts with the inclusion of new components for ET estimation at varying temporal and spatial scales under complex terrain. Following a coupled remote sensing and surface energy balance approach, this study emphasizes the structure and function of the Surface Energy Balance with Topography Algorithm (SEBTA). With the aid of the elevation and landscape information, such as slope and aspect parameters derived from the digital elevation model (DEM), and the vegetation cover derived from satellite images, the SEBTA can fully account for the dynamic impacts of complex terrain and changing land cover in concert with some varying kinetic parameters (i.e., roughness and zero-plane displacement) over time. Besides, the dry and wet pixels can be recognized automatically and dynamically in image processing thereby making the SEBTA more sensitive to derive the sensible heat flux for ET estimation. To prove the application potential, the SEBTA was carried out to present the robust estimates of 24 h solar radiation over time, which leads to the smooth simulation of the ET over seasons in northern China where the regional climate and vegetation cover in different seasons compound the ET calculations. The SEBTA was validated by the measured data at the ground level. During validation, it shows that the consistency index reached 0.92 and the correlation coefficient was 0.87.

  19. A coupled remote sensing and the Surface Energy Balance with Topography Algorithm (SEBTA) to estimate actual evapotranspiration over heterogeneous terrain

    NASA Astrophysics Data System (ADS)

    Gao, Z. Q.; Liu, C. S.; Gao, W.; Chang, N.-B.

    2011-01-01

    Evapotranspiration (ET) may be used as an ecological indicator to address the ecosystem complexity. The accurate measurement of ET is of great significance for studying environmental sustainability, global climate changes, and biodiversity. Remote sensing technologies are capable of monitoring both energy and water fluxes on the surface of the Earth. With this advancement, existing models, such as SEBAL, S_SEBI and SEBS, enable us to estimate the regional ET with limited temporal and spatial coverage in the study areas. This paper extends the existing modeling efforts with the inclusion of new components for ET estimation at different temporal and spatial scales under heterogeneous terrain with varying elevations, slopes and aspects. Following a coupled remote sensing and surface energy balance approach, this study emphasizes the structure and function of the Surface Energy Balance with Topography Algorithm (SEBTA). With the aid of the elevation and landscape information, such as slope and aspect parameters derived from the digital elevation model (DEM), and the vegetation cover derived from satellite images, the SEBTA can account for the dynamic impacts of heterogeneous terrain and changing land cover with some varying kinetic parameters (i.e., roughness and zero-plane displacement). Besides, the dry and wet pixels can be recognized automatically and dynamically in image processing thereby making the SEBTA more sensitive to derive the sensible heat flux for ET estimation. To prove the application potential, the SEBTA was carried out to present the robust estimates of 24 h solar radiation over time, which leads to the smooth simulation of the ET over seasons in northern China where the regional climate and vegetation cover in different seasons compound the ET calculations. The SEBTA was validated by the measured data at the ground level. During validation, it shows that the consistency index reached 0.92 and the correlation coefficient was 0.87.

  20. Estimating riparian and agricultural evapotranspiration by reference crop evapotranspiration and MODIS Enhanced Vegetation Index

    USGS Publications Warehouse

    Nagler, Pamela L.; Glenn, Edward P.; Nguyen, Uyen; Scott, Russell; Doody, Tania

    2013-01-01

    Dryland river basins frequently support both irrigated agriculture and riparian vegetation and remote sensing methods are needed to monitor water use by both crops and natural vegetation in irrigation districts. We developed an algorithm for estimating actual evapotranspiration (ETa) based on the Enhanced Vegetation Index (EVI) from the Moderate Resolution Imaging Spectrometer (MODIS) sensor on the EOS-1 Terra satellite and locally-derived measurements of reference crop ET (ETo). The algorithm was calibrated with five years of ETa data from three eddy covariance flux towers set in riparian plant associations on the upper San Pedro River, Arizona, supplemented with ETa data for alfalfa and cotton from the literature. The algorithm was based on an equation of the form ETa = ETo [a(1 − e−bEVI) − c], where the term (1 − e−bEVI) is derived from the Beer-Lambert Law to express light absorption by a canopy, with EVI replacing leaf area index as an estimate of the density of light-absorbing units. The resulting algorithm capably predicted ETa across riparian plants and crops (r2 = 0.73). It was then tested against water balance data for five irrigation districts and flux tower data for two riparian zones for which season-long or multi-year ETa data were available. Predictions were within 10% of measured results in each case, with a non-significant (P = 0.89) difference between mean measured and modeled ETa of 5.4% over all validation sites. Validation and calibration data sets were combined to present a final predictive equation for application across crops and riparian plant associations for monitoring individual irrigation districts or for conducting global water use assessments of mixed agricultural and riparian biomes.

  1. Evaluating the complementary relationship of evapotranspiration in the alpine steppe of the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Ma, Ning; Zhang, Yinsheng; Szilagyi, Jozsef; Guo, Yanhong; Zhai, Jianqing; Gao, Haifeng

    2015-02-01

    The complementary relationship (CR) of evapotranspiration allows the estimation of the actual evapotranspiration rate (ETa) of the land surface using only routine meteorological data, which is of great importance in the Tibetan Plateau (TP) due to its sparse observation network. With the highest in situ automatic climate observation system in a typical semiarid alpine steppe region of the TP, the wind function of Penman was replaced by one based on the Monin-Obukhov Similarity theory for calculating the potential evapotranspiration rate (ETp); the Priestley-Taylor coefficient, α, was estimated using observations in wet days; and the slope of the saturation vapor pressure curve was evaluated at an estimate of the wet surface temperature, provided the latter was smaller than the actual air temperature. A symmetric CR was obtained between the observed daily actual and potential evapotranspiration. Local calibration of the parameter value (in this order) is key to obtaining a symmetric CR: α, wet environment air temperature (Twea), and wind function. Also, present symmetric CR contradicts previous research that used default parameter values for claiming an asymmetric CR in arid and semiarid regions of the TP. The effectiveness of estimating the daily ETa via symmetric CR was greatly improved when local calibrations were implemented. At the same time, an asymmetric CR was found between the observed daily ETa and pan evaporation rates (Epan), both for D20 aboveground and E601B sunken pans. The daily ETa could also be estimated by coupling the Epan of D20 aboveground and/or E601B sunken pan through CR. The former provided good descriptors for observed ETa, while the latter still tended to overestimate it to some extent.

  2. Estimation of Evapotranspiration of Almond orchards using Remote Sensing based SEBAL model in Central Valley, California

    NASA Astrophysics Data System (ADS)

    Roy, S.; Ustin, S.; Kefauver, S. C.

    2009-12-01

    Evapotranspiration is one of the main components of the hydrologic cycle and its impact to hydrology, agriculture,forestry and environmental studies is very crucial. SEBAL (Surface Energy Balance Algorithm for Land) is an image-processing model comprised of twenty-five computational sub-models that computes actual evapotranspiration (ETa) and other energy exchanges as a component of energy balance which is used to derive the surface radiation balance equation for the net surface radiation flux (Rn) on a pixel-by-pixel basis. For this study, SEBAL method is applied to Level 1B dataset of visible, near-infrared and thermal infrared radiation channels of MASTER instrument on-board NASA-DC 8 flight. This paper uses the SEBAL method to (1) investigate the spatial distribution property of land surface temperature (Ls), NDVI, and ETa over the San Joaquin valley. (2) Estimate actual evapotranspiration of almond class on pixel-by-pixel basis in the Central valley, California. (3) Comparison of actual Evapotranspiration obtained from SEBAL model with reference evapotranspiration (Eto) using Penman Monteiths method based on the procedures and available data from California Irrigation Management Information System (CIMIS) stations. The results of the regression between extracted land surface temperature, NDVI and, evapotranspiration show negative (-) correlation. On the other hand Ls possessed a slightly stronger negative correlation with the ETa than with NDVI for Almond class. The correlation coefficient of actual ETa estimates from remote sensing with Reference ETo from Penmann Monteith are 0.8571. ETa estimated for almond crop from SEBAL were found to be almost same with the CIMIS_Penman Monteith method with bias of 0.77 mm and mean percentage difference is 0.10%. These results indicate that combination of MASTER data with surface meteorological data could provide an efficient tool for the estimation of regional actual ET used for water resources and irrigation scheduling

  3. Comparative analysis of the actual evapotranspiration of Flemish forest and cropland, using the soil water balance model WAVE

    NASA Astrophysics Data System (ADS)

    Verstraeten, W. W.; Muys, B.; Feyen, J.; Veroustraete, F.; Minnaert, M.; Meiresonne, L.; de Schrijver, A.

    2005-05-01

    This paper focuses on the quantification of the green - vegetation related - water flux of a forest stand in the temperate lowland of Flanders. The underlying reason of the research was to develop a methodology for assessing the impact of forests on the hydrologic cycle in comparison to agriculture. The approach tested for calculating the water consumption by forests was based on the application of the soil water balance model WAVE. The study involved the collection of data from 14 forest stands, the calibration and validation of the WAVE model, and the comparison of the water use (WU) components - transpiration, soil and interception evaporation - between forest and cropland. For model calibration purposes simulated and measured time series of soil water content at different soil depths, period March 2000-August 2001, were compared. A multiple-site validation was conducted as well. Actual tree transpiration calculated with sap flow measurements in three forest stands gave similar results for two of the three stands of pine (Pinus sylvestris L.), but WAVE overestimated the actual measured transpiration for a stand of poplar (Populus sp.). A useful approach to compare the WU components of forest versus cropland is scenario analysis based on the validated WAVE model. The statistical Profile Analysis method was implemented to explore and analyse the simulated WU time-series. With an average annual rainfall of 819 mm, the results show that forests in Flanders consume more water than agricultural crops. A 30 years average of 491 mm for 10 forests stands versus 398 mm for 10 cropped agricultural fields was derived. The WU components, on yearly basis, also differ between the two land use types (transpiration: 315 mm for forest and 261 mm for agricultural land use; soil evaporation: 47 mm and 131 mm, for forest and cropland, respectively). Forest canopy interception evaporation was estimated at 126 mm, while it was negligible for cropland.

  4. Comparative analysis of the actual evapotranspiration of Flemish forest and cropland, using the soil water balance model WAVE

    NASA Astrophysics Data System (ADS)

    Verstraeten, W. W.; Muys, B.; Feyen, J.; Veroustraete, F.; Minnaert, M.; Meiresonne, L.; de Schrijver, A.

    2005-09-01

    This paper focuses on the quantification of the green - vegetation related - water flux of forest stands in the temperate lowland of Flanders. The underlying reason of the research was to develop a methodology for assessing the impact of forests on the hydrologic cycle in comparison to agriculture. The tested approach for calculating the water use by forests was based on the application of the soil water balance model WAVE. The study involved the collection of data from 14 forest stands, the calibration and validation of the WAVE model, and the comparison of the water use (WU) components - transpiration, soil and interception evaporation - between forest and cropland. For model calibration purposes simulated and measured time series of soil water content at different soil depths, period March 2000-August 2001, were compared. A multiple-site validation was conducted as well. Actual tree transpiration calculated with sap flow measurements in three forest stands gave similar results for two of the three stands of pine (Pinus sylvestris L.), but WAVE overestimated the actual measured transpiration for a stand of poplar (Populus sp.). A useful approach to compare the WU components of forest versus cropland is scenario analysis based on the validated WAVE model. The statistical Profile Analysis method was implemented to explore and analyse the simulated WU time series. With an average annual rainfall of 819 mm, the results reveal that forests in Flanders consume more water than agricultural crops. A 30 years average of 491 mm for 10 forests stands versus 398 mm for 10 cropped agricultural fields was derived. The WU components, on yearly basis, also differ between the two land use types (transpiration: 315 mm for forest and 261 mm for agricultural land use; soil evaporation: 47 mm and 131 mm, for forest and cropland, respectively). Forest canopy interception evaporation was estimated at 126 mm, while it was negligible for cropland.

  5. Mapping Seasonal Evapotranspiration and Root Zone Soil Moisture using a Hybrid Modeling Approach over Vineyards

    NASA Astrophysics Data System (ADS)

    Geli, H. M. E.

    2015-12-01

    Estimates of actual crop evapotranspiration (ETa) at field scale over the growing season are required for improving agricultural water management, particularly in water limited and drought prone regions. Remote sensing data from multiple platforms such as airborne and Landsat-based sensors can be used to provide these estimates. Combining these data with surface energy balance models can provide ETa estimates at sub- field scale as well as information on vegetation stress and soil moisture conditions. However, the temporal resolution of airborne and Landsat data does not allow for a continuous ETa monitoring over the course of the growing season. This study presents the application of a hybrid ETa modeling approach developed for monitoring daily ETa and root zone available water at high spatial resolutions. The hybrid ETa modeling approach couples a thermal-based energy balance model with a water balance-based scheme using data assimilation. The two source energy balance (TSEB) model is used to estimate instantaneous ETa which can be extrapolated to daily ETa using a water balance model modified to use the reflectance-based basal crop coefficient for interpolating ETa in between airborne and/or Landsat overpass dates. Moreover, since it is a water balance model, the soil moisture profile is also estimated. The hybrid ETa approach is applied over vineyard fields in central California. High resolution airborne and Landsat imagery were used to drive the hybrid model. These images were collected during periods that represented different vine phonological stages in 2013 growing season. Estimates of daily ETa and surface energy balance fluxes will be compared with ground-based eddy covariance tower measurements. Estimates of soil moisture at multiple depths will be compared with measurements.

  6. Assessing spatiotemporal variation in actual evapotranspiration for semi-arid watersheds in northwest China: Evaluation of two complementary-based methods

    NASA Astrophysics Data System (ADS)

    Matin, Mir A.; Bourque, Charles P.-A.

    2013-04-01

    SummaryWater vapor generated locally by actual evapotranspiration (AET) is important both to the recycling of water regionally and to the long term sustainability of desert-oases in the semi-arid-to-arid region of northwest (NW) China. An accurate assessment of AET is central to describing the hydrologic status of watersheds. Conventional methods of estimating AET from meteorological point data are generally not appropriate for regions with high spatial variability, particularly with respect to landcover and topography. Insufficient monitoring stations make it particularly difficult to estimate AET that is spatially representative of large areas. The objective of this study was to estimate spatially-distributed monthly AET for a complex landscape, consisting of deserts, oases, and mountains, with climate and landcover data generated primarily from remote sensing (RS) data. In this study, we used two complementary relationship (CR)-based methods to estimate monthly reference evapotranspiration (ETo) and AET over a 10-year period (2000-2009) for two large watersheds in NW China. In evaluating the performance of CR-based methods, we compared point-estimates of ETo and AET generated with the two methods (generated either by using climate-station data or by extracting point-estimates from end products produced from RS-data) against (i) climate-station-based estimates of ETo calculated with the FAO Penman-Monteith (P-M) equation and from pan-evaporation data, and (ii) geographically-corresponding point-estimates of AET extracted from the MODIS global product of AET (MOD16) recently developed by Mu et al. (2011, Remote Sensing of Environment, 115, 1781-1800). Point-extractions of AET from MOD16-products were the least representative, when compared to ETo and AET calculated with the other methods. Between CR-based methods, the Venturini et al. (2008, Remote Sensing of Environment, 112, 132-141) method provided the best comparison with ETo calculated with the P-M equation

  7. Assessing the impact of end-member selection on the accuracy of satellite-based spatial variability models for actual evapotranspiration estimation

    NASA Astrophysics Data System (ADS)

    Long, Di; Singh, Vijay P.

    2013-05-01

    This study examines the impact of end-member (i.e., hot and cold extremes) selection on the performance and mechanisms of error propagation in satellite-based spatial variability models for estimating actual evapotranspiration, using the triangle, surface energy balance algorithm for land (SEBAL), and mapping evapotranspiration with high resolution and internalized calibration (METRIC) models. These models were applied to the soil moisture-atmosphere coupling experiment site in central Iowa on two Landsat Thematic Mapper/Enhanced Thematic Mapper Plus acquisition dates in 2002. Evaporative fraction (EF, defined as the ratio of latent heat flux to availability energy) estimates from the three models at field and watershed scales were examined using varying end-members. Results show that the end-members fundamentally determine the magnitudes of EF retrievals at both field and watershed scales. The hot and cold extremes exercise a similar impact on the discrepancy between the EF estimates and the ground-based measurements, i.e., given a hot (cold) extreme, the EF estimates tend to increase with increasing temperature of cold (hot) extreme, and decrease with decreasing temperature of cold (hot) extreme. The coefficient of determination between the EF estimates and the ground-based measurements depends principally on the capability of remotely sensed surface temperature (Ts) to capture EF (i.e., depending on the correlation between Ts and EF measurements), being slightly influenced by the end-members. Varying the end-members does not substantially affect the standard deviation and skewness of the EF frequency distributions from the same model at the watershed scale. However, different models generate markedly different EF frequency distributions due to differing model physics, especially the limiting edges of EF defined in the remotely sensed vegetation fraction (fc) and Ts space. In general, the end-members cannot be properly determined because (1) they do not

  8. Evaluation of the relation between evapotranspiration and normalized difference vegetation index for downscaling the simplified surface energy balance model

    USGS Publications Warehouse

    Haynes, Jonathan V.; Senay, Gabriel B.

    2012-01-01

    The Simplified Surface Energy Balance (SSEB) model uses satellite imagery to estimate actual evapotranspiration (ETa) at 1-kilometer resolution. SSEB ETa is useful for estimating irrigation water use; however, resolution limitations restrict its use to regional scale applications. The U.S. Geological Survey investigated the downscaling potential of SSEB ETa from 1 kilometer to 250 meters by correlating ETa with the Normalized Difference Vegetation Index (NDVI) from the Moderate Resolution Imaging Spectroradiometer instrument (MODIS). Correlations were studied in three arid to semiarid irrigated landscapes of the Western United States (Escalante Valley near Enterprise, Utah; Palo Verde Valley near Blythe, California; and part of the Columbia Plateau near Quincy, Washington) during several periods from 2002 to 2008. Irrigation season ETa-NDVI correlations were lower than expected, ranging from R2 of 0.20 to 0.61 because of an eastward 2-3 kilometer shift in ETa data. The shift is due to a similar shift identified in the land-surface temperature (LST) data from the MODIS Terra satellite, which is used in the SSEB model. Further study is needed to delineate the Terra LST shift, its effect on SSEB ETa, and the relation between ETa and NDVI.

  9. Estimation of total available water in the soil layer by integrating actual evapotranspiration data in a remote sensing-driven soil water balance

    NASA Astrophysics Data System (ADS)

    Campos, Isidro; González-Piqueras, Jose; Carrara, Arnaud; Villodre, Julio; Calera, Alfonso

    2016-03-01

    The total available water (τ) by plants that could be stored in its root soil layer is a key parameter when applying soil water balance models. Since the transpiration rate of a vegetation stand could be the best proxy about the soil water content into the root soil layer, we propose a methodology for estimating τ by using as basic inputs the evapotranspiration rate of the stand and time series of multispectral imagery. This methodology is based on the inverted formulation of the soil water balance model. The inversion of the model was addressed by using an iterative approach, which optimizes the τ parameter to minimize the difference between measured and modeled ET. This methodology was tested for a Mediterranean holm oak savanna (dehesa) for which eddy covariance measurements of actual ET were available. The optimization procedure was performed by using a continuous dataset (in 2004) of daily ET measurements and 16 sets of 8 daily ET measurements, resulting in τ values of 325 and 305 mm, respectively. The use of these τ values in the RSWB model for the validation period (2005-2008) allowed us to estimate dehesa ET with a RMSE = 0.48 mm/day. The model satisfactorily reproduces the water stress process. The sensitivity of τ estimates was evaluated regarding two of the more uncertain parameters in the RSWB model. These parameters are the average fraction of τ that can be depleted from the root zone without producing moisture stress (pτ) and the soil evaporation component. The results of this analysis indicated relatively little influence from the evaporation component and the need for adequate knowledge about pτ for estimating τ.

  10. Method for automatic determination of soybean actual evapotranspiration under open top chambers (OTC) subjected to effects of water stress and air ozone concentration.

    PubMed

    Rana, Gianfranco; Katerji, Nader; Mastrorilli, Marcello

    2012-10-01

    The present study describes an operational method, based on the Katerji et al. (Eur J Agron 33:218-230, 2010) model, for determining the daily evapotranspiration (ET) for soybean inside open top chambers (OTCs). It includes two functions, calculated day par day, making it possible to separately take into account the effects of concentrations of air ozone and plant water stress. This last function was calibrated in function of the daily values of actual water reserve in the soil. The input variables of the method are (a) the diurnal values of global radiation and temperature, usually measured routinely in a standard weather station; (b) the daily values of the AOT40 index accumulated (accumulated ozone over a threshold of 40 ppb during daylight hours, when global radiation exceeds 50 Wm(-2)) determined inside the OTC; and (c) the actual water reserve in the soil, at the beginning of the trial. The ensemble of these input variables can be automatable; thus, the proposed method could be applied in routine. The ability of the method to take into account contrasting conditions of ozone air concentration and water stress was evaluated over three successive years, for 513 days, in ten crop growth cycles, excluding the days employed to calibrate the method. Tests were carried out in several chambers for each year and take into account the intra- and inter-year variability of ET measured inside the OTCs. On the daily scale, the slope of the linear regression between the ET measured by the soil water balance and that calculated by the proposed method, under different water conditions, are 0.98 and 1.05 for the filtered and unfiltered (or enriched) OTCs with root mean square error (RMSE) equal to 0.77 and 1.07 mm, respectively. On the seasonal scale, the mean difference between measured and calculated ET is equal to +5% and +11% for the filtered and unfiltered OTCs, respectively. The ability of the proposed method to estimate the daily and seasonal ET inside the OTCs is

  11. A 3-D Generalization of the Budyko Framework Captures the Mutual Interdependence Between Long-Term Mean Annual Precipitation, Actual and Potential Evapotranspiration

    NASA Astrophysics Data System (ADS)

    Carmona, A. M.; Poveda, G.

    2012-12-01

    We study the behavior of the 3-D parameter space defined by Φ =PET/P (so-called Aridity Index), Ψ =AET/P, and Ω =AET/PET, where P denotes mean annual precipitation, and PET and AET denote mean annual potential and actual evapotranspiration, respectively. Using information from the CLIMWAT 2.0 database (www.fao.org/nr/water/infores_databases_climwat.html) for P and PET, we estimate AET using both Budyko's and Turc's equations. Our results indicate that the well-known Budyko function that relates Φ vs.Ψ corresponds to a particular bi-dimensional cross-section of a broader coupling existing between Φ, Ψ and Ω (Figure 1a), and in turn of the mutual interdependence between P, PET and AET. The behavior of the three bi-dimensional projections are clearly parameterized by the remaining ortogonal parameter, such that: (i) the relation Φ vs. Ψ is defined by physically consistent varying values of Ω (Figure 1b); (ii) the relation Ω vs. Ψ is defined by physically consistent varying values of the Aridity Index,Φ (Figure 1c), and (iii) the relation Ω vs. Φ is defined by physically consistent varying values of Ψ (Figure 1d). Interestingly, we show that Φ and Ω are related by a power law, Φ~Ω-θ, with scaling exponent θ=1.15 (R2=0.91, n=3420) for the whole world (Figure 1d). Mathematical functions that model the three bi-dimensional projections and the surface defining the interdependence between Φ, Ψ and Ω will be presented. Our results provide a new framework to understand the coupling between the long-term mean annual water and energy balances in river basins, and the hydrological effects brought about by climate change, while taking into account the mutual interdependence between the three non-dimensional parameters Φ, Ψ and Ω, and in turn between P, PET and AET. Figure 1. (a) Three-dimensional rendering of sample values of Φ =PET/P (so-called Aridity Index), Ψ =AET/P, and Ω=AET/PET. Bi-dimensional projections of: (b) relation Φ vs.

  12. eta. prime -. eta. -. pi. sup 0 mixing

    SciTech Connect

    Bagchi, B. ); Lahiri, A. ); Niyogi, S. )

    1990-05-01

    We have examined the saturation of anomalous Ward identities by the low-lying pseudoscalars {pi}{sup 0}, {eta}, and {eta}{prime} to determine the sizes of {eta}{prime}-{eta}, {pi}{sup 0}-{eta}, and {pi}{sup 0}-{eta}{prime} mixing angles. The {eta}{prime}-{eta} mixing angle turns out to be about {minus}20{degree} which is consistent with the recent findings. Our estimate for the {pi}{sup 0}-{eta} mixing angle shows that it could be bigger than the older value obtained from the {rho}-{omega} mixing, baryon mass splittings, and kaon mass difference.

  13. Comment on 'Shang S. 2012. Calculating actual crop evapotranspiration under soil water stress conditions with appropriate numerical methods and time step. Hydrological Processes 26: 3338-3343. DOI: 10.1002/hyp.8405'

    NASA Technical Reports Server (NTRS)

    Yatheendradas, Soni; Narapusetty, Balachandrudu; Peters-Lidard, Christa; Funk, Christopher; Verdin, James

    2014-01-01

    A previous study analyzed errors in the numerical calculation of actual crop evapotranspiration (ET(sub a)) under soil water stress. Assuming no irrigation or precipitation, it constructed equations for ET(sub a) over limited soil-water ranges in a root zone drying out due to evapotranspiration. It then used a single crop-soil composite to provide recommendations about the appropriate usage of numerical methods under different values of the time step and the maximum crop evapotranspiration (ET(sub c)). This comment reformulates those ET(sub a) equations for applicability over the full range of soil water values, revealing a dependence of the relative error in numerical ET(sub a) on the initial soil water that was not seen in the previous study. It is shown that the recommendations based on a single crop-soil composite can be invalid for other crop-soil composites. Finally, a consideration of the numerical error in the time-cumulative value of ET(sub a) is discussed besides the existing consideration of that error over individual time steps as done in the previous study. This cumulative ET(sub a) is more relevant to the final crop yield.

  14. Evaluation of the Event Driven Phenology Model Coupled to the VegET Evapotranspiration Model Using Spatially Explicit Comparisons with Independent Reference Data

    NASA Astrophysics Data System (ADS)

    Kovalskyy, V.; Henebry, G. M.; Roy, D. P.; Senay, G. B.

    2011-12-01

    Vegetation growing cycles have a profound influence on regional evapotranspiration regimes. The recently developed Event Driven Phenology Model (EDPM) is an empirical crop-specific phenology model with data assimilation capabilities. Deployed in prognostic mode, the EDPM uses weather forcing data to produce daily estimates of phenology coefficients; and in diagnostic mode a one-dimensional Kalman filter is used to adjust EDPM estimates with satellite normalized difference vegetation index (NDVI) retrievals. In this study the EDPM is coupled to the VegET model that uses the Penman-Monteith equation to calculate reference ET and a water balance model for water stress coefficients to derive daily actual evapotranspiration. The coupled models were run for the croplands of the U.S. Northern Great Plains for three annual growing seasons to derive 8-day total actual evapotranspiration (ETa) estimates at 0.05° spatial resolution. The models were driven by North American Land Data Assimilation System (NLDAS) weather forcing and parameterized using annual MODIS cropland cover maps. Regional validation of the modeled NDVI and ETa were undertaken by comparison with MODIS NDVI and MODIS ETa products respectively. The modeled NDVI had a median coefficient of determination (r2) of 0.83 and a root mean square error (RMSE) of 0.15 within study area. With the EDPM deployed in both prognostic and diagnostic modes, the modeled ETa had r2 of 0.75 and RMSE of about 25% of season average ETa per observation period. With small computational effort these results yield comparable accuracy to those from computationally complex models of ETa which require more parameterization. The performance of the coupling scheme demonstrates that the modeling approach is a promising avenue for regional application studies.

  15. Searches for B0 Decays to eta K0, eta eta,eta' eta', eta phi, and eta'phi

    SciTech Connect

    Aubert, B.

    2006-07-31

    The authors search for B{sup 0} meson decays into two-body combinations of K{sup 0}, {eta}, {eta}', and {phi} mesons in 324 million B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. They measure the following branching fractions (upper limits at 90% confidence level) in units of 10{sup -6}: {Beta}(B{sup 0} {yields} {eta}K{sup 0}) = 1.8{sub -0.6}{sup +0.7} {+-} 0.1 (< 2.9), {Beta}(B{sup 0} {yields} {eta}{eta}) = 1.1{sub -0.4}{sup +0.5} {+-} 0.1(< 1.8), {Beta}(B{sup 0} {yields} {eta}{phi}) = 0.1 {+-} 0.2 {+-} 0.1(< 0.6), {Beta}(B{sup 0} {yields} {eta}'{phi}) = 0.2{sub -0.3}{sup +0.4} {+-} 0.1(< 1.0), and {Beta}(B{sup 0} {yields} {eta}'{eta}') = 1.0{sub -0.6}{sup +0.8} {+-} 0.1 (< 2.4), where the first error is statistical and the second systematic.

  16. Drought trends indicated by evapotranspiration deficit over the contiguous United States during 1896-2013

    NASA Astrophysics Data System (ADS)

    Kim, Daeha; Rhee, Jinyoung

    2016-04-01

    Evapotranspiration (ET) has received a great attention in drought assessment as it is closely related to atmospheric water demand. The hypothetical potential ET (ETp) has been predominantly used, nonetheless it does not actually exist in the hydrologic cycle. In this work, we used a complementary method for ET estimation to obtain wet-environment ET (ETw) and actual ET (ETa) from routinely observed climatic data. By combining ET deficits (ETw minus ETa) and the structure of the Standardized Precipitation-Evapotranspiration Index (SPEI), we proposed a novel ET-based drought index, the Standardized Evapotranspiration Deficit Index (SEDI). We carried out historical drought identification for the contiguous United States using temperature datasets of the PRISM Climate Group. SEDI presented spatial distributions of drought areas similar to the Palmer Drought Severity Index (PDSI) and Standardized Precipitation Index (SPI) for major drought events. It indicates that SEDI can be used for validating other drought indices. Using the non-parametric Mann-Kendall test, we found a significant decreasing trend of SEDI (increasing drought risk) similar to PDSI and SPI in the western United States. This study suggests a potential of ET-based indices for drought quantification even with no involvement of precipitation data.

  17. Actual evapotranspiration estimation in a Mediterranean mountain region by means of Landsat-5 TM and TERRA/AQUA MODIS imagery and Sap Flow measurements in Pinus sylvestris forest stands.

    NASA Astrophysics Data System (ADS)

    Cristóbal, J.; Poyatos, R.; Ninyerola, M.; Pons, X.; Llorens, P.

    2009-04-01

    Evapotranspiration monitoring has important implications on global and regional climate modelling, as well as in the knowledge of the hydrological cycle and in the assessment of environmental stress that affects forest and agricultural ecosystems. An increase of evapotranspiration while precipitation remains constant, or is reduced, could decrease water availability for natural and agricultural systems and human needs. Consequently, water balance methods, as the evapotranspiration modelling, have been widely used to estimate crop and forest water needs, as well as the global change effects. Nowadays, radiometric measurements provided by Remote Sensing and GIS analysis are the technologies used to compute evapotranspiration at regional scales in a feasible way. Currently, the 38% of Catalonia (NE of the Iberian Peninsula) is covered by forests, and one of the most important forest species is Scots Pine (Pinus sylvestris) which represents the 18.4% of the area occupied by forests. The aim of this work is to model actual evapotranspiration in Pinus sylvestris forest stands, in a Mediterranean mountain region, using remote sensing data, and compare it with stand-scale sap flow measurements measured in the Vallcebre research area (42° 12' N, 1° 49' E), in the Eastern Pyrenees. To perform this study a set of 30 cloud-free TERRA-MODIS images and 10 Landsat-5 TM images of path 198 and rows 31 and 32 from June 2003 to January 2005 have been selected to perform evapotranspiration modelling in Pinus sylvestris forest stands. TERRA/AQUA MODIS images have been downloaded by means of the EOS Gateway. We have selected two different types of products which contain the remote sensing data we have used to model daily evapotranspiration, daily LST product and daily calibrated reflectances product. Landsat-5 TM images have been corrected by means of conventional techniques based on first order polynomials taking into account the effect of land surface relief using a Digital

  18. Automated calculation of the evapotranspiration and crop coefficients for a large number of peatland sites using diurnal groundwater table fluctuations

    NASA Astrophysics Data System (ADS)

    Maurer, Eike; Bechtold, Michel; Dettmann, Ullrich; Tiemeyer, Bärbel

    2014-05-01

    values were determined from precipitation events and the related water level increase. Parameter values in this routine were systematically varied to obtain the lowest standard error of Sy. Errors were obtained by bootstrapping. The resulting Sy-values correspond well to peatland type and soil properties. After rule-based filtering of the time series, in a third step, the actual evapotranspiration ETa is calculated by the original White-method and a modification by Hays (2003). Daily values of ETa and ET0 are used to derive crop coefficients, which are then aggregated to monthly and annual Kc-values. Applying the method to a large number of sites resulted in plausible crop coefficients which compare well to previously published values of peatland evapotranspiration, as far as information on similar vegetation is available.

  19. Actual evapotranspiration estimation in a Mediterranean mountain region by means of Landsat-5 TM and TERRA/AQUA MODIS imagery and Sap Flow measurements in Pinus sylvestris forest stands.

    NASA Astrophysics Data System (ADS)

    Cristóbal, J.; Poyatos, R.; Ninyerola, M.; Pons, X.; Llorens, P.

    2009-04-01

    Evapotranspiration monitoring has important implications on global and regional climate modelling, as well as in the knowledge of the hydrological cycle and in the assessment of environmental stress that affects forest and agricultural ecosystems. An increase of evapotranspiration while precipitation remains constant, or is reduced, could decrease water availability for natural and agricultural systems and human needs. Consequently, water balance methods, as the evapotranspiration modelling, have been widely used to estimate crop and forest water needs, as well as the global change effects. Nowadays, radiometric measurements provided by Remote Sensing and GIS analysis are the technologies used to compute evapotranspiration at regional scales in a feasible way. Currently, the 38% of Catalonia (NE of the Iberian Peninsula) is covered by forests, and one of the most important forest species is Scots Pine (Pinus sylvestris) which represents the 18.4% of the area occupied by forests. The aim of this work is to model actual evapotranspiration in Pinus sylvestris forest stands, in a Mediterranean mountain region, using remote sensing data, and compare it with stand-scale sap flow measurements measured in the Vallcebre research area (42° 12' N, 1° 49' E), in the Eastern Pyrenees. To perform this study a set of 30 cloud-free TERRA-MODIS images and 10 Landsat-5 TM images of path 198 and rows 31 and 32 from June 2003 to January 2005 have been selected to perform evapotranspiration modelling in Pinus sylvestris forest stands. TERRA/AQUA MODIS images have been downloaded by means of the EOS Gateway. We have selected two different types of products which contain the remote sensing data we have used to model daily evapotranspiration, daily LST product and daily calibrated reflectances product. Landsat-5 TM images have been corrected by means of conventional techniques based on first order polynomials taking into account the effect of land surface relief using a Digital

  20. Eta-nucleon interaction and nuclear production of eta mesons

    SciTech Connect

    Liu, L.C.

    1993-08-01

    Eta-nucleon interaction and eta-nucleus dynamics are discussed. The possibility of using {eta} to probe unnatural-parity nuclear states and to study spin-isospin correlations between two nucleons are demonstrated.

  1. Modeling landscape evapotranspiration by integrating land surface phenology and a water balance algorithm

    USGS Publications Warehouse

    Senay, Gabriel B.

    2008-01-01

    The main objective of this study is to present an improved modeling technique called Vegetation ET (VegET) that integrates commonly used water balance algorithms with remotely sensed Land Surface Phenology (LSP) parameter to conduct operational vegetation water balance modeling of rainfed systems at the LSP’s spatial scale using readily available global data sets. Evaluation of the VegET model was conducted using Flux Tower data and two-year simulation for the conterminous US. The VegET model is capable of estimating actual evapotranspiration (ETa) of rainfed crops and other vegetation types at the spatial resolution of the LSP on a daily basis, replacing the need to estimate crop- and region-specific crop coefficients.

  2. Evapotranspiration partitioning, stomatal conductance, and components of the water balance: A special case of a desert ecosystem in China

    NASA Astrophysics Data System (ADS)

    Zhao, Wenzhi; Liu, Bing; Chang, Xuexiang; Yang, Qiyue; Yang, Yuting; Liu, Zhiling; Cleverly, James; Eamus, Derek

    2016-07-01

    Partitioning evapotranspiration (ET) into its components reveals details of the processes that underlie ecosystem hydrologic budgets and their feedback to the water cycle. We measured rates of actual evapotranspiration (ETa), canopy transpiration (Tc), soil evaporation (Eg), canopy-intercepted precipitation (EI), and patterns of stomatal conductance of the desert shrub Calligonum mongolicum in northern China to determine the water balance of this ecosystem. The ETa was 251 ± 8 mm during the growing period, while EI, Tc, and Eg accounted for 3.2%, 63.9%, and 31.3%, respectively, of total water use (256 ± 4 mm) during the growing period. In this unique ecosystem, groundwater was the main water source for plant transpiration and soil evaporation, Tc and exceeded 60% of the total annual water used by desert plants. ET was not sensitive to air temperature in this unique desert ecosystem. Partitioning ET into its components improves our understanding of the mechanisms that underlie adaptation of desert shrubs, especially the role of stomatal regulation of Tc as a determinant of ecosystem water balance.

  3. Quantifying the impact of changes in crop area on evapotranspiration regimes in the US corn and soybean belts through phenological modeling and data assimilation

    NASA Astrophysics Data System (ADS)

    Kovalskyy, V.; Henebry, G. M.

    2010-12-01

    In recent years, fluctuations in food, feed, and fuel prices have led to shifts in the area of cropland dedicated to maize and soybean cultivation in the Northern Great Plains. We report here on a modeling experiment that compares three different simulated scenarios for actual evapotranspiration (ETa) from maize-soybean dominated areas in North Dakota, South Dakota, Nebraska, Iowa, and Minnesota during the 2000-2009 growing seasons. Scenario 1 relies on MODIS-derived crop maps to provide a baseline of subpixel crop proportions; Scenario 2 increases the proportion of maize by to 100 percent; Scenario 3 substitutes grassland for half the maize. We use a simple soil water balance model of ETa linked to an empirically derived crop specific phenology model also capable of producing seasonal trajectories of canopy attributes. This coupled model has been successfully deployed using flux tower records from multiple locations in the central US. Forcing the coupled model using data from NLDAS, we derive seasonal trajectories of daily NDVI and ETa as well as phenological transition points for maize, soybean, and grassland for each scenario. Seasonal differences in ETa among the three scenarios underscore the importance of how land use modulates land surface phenologies and, in turn, water and energy balances.

  4. Search for B Meson Decays to eta' eta' K

    SciTech Connect

    Aubert, B.

    2006-05-05

    The authors describe searches for decays of B mesons to the charmless final states {eta}'{eta}'K. The data consist of 228 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation, collected with the BABAR detector at the Stanford Linear Accelerator Center. The 90% confidence level upper limits for the branching fractions are {Beta}(B{sup 0} {yields} {eta}'{eta}'K{sup 0}) < 31 x 10{sup -6} and {Beta}(B{sup +} {yields} {eta}'{eta}'K{sup +}) < 25 x 10{sup -6}.

  5. The complementary relationship (CR) approach aids evapotranspiration estimation in the data scarce region of Tibetan Plateau: symmetric and asymmetric perspectives

    NASA Astrophysics Data System (ADS)

    Ma, N.; Zhang, Y.; Szilagyi, J.; Xu, C. Y.

    2015-12-01

    While the land surface latent and sensible heat release in the Tibetan Plateau (TP) could greatly influence the Asian monsoon circulation, the actual evapotranspiration (ETa) information in the TP has been largely hindered by its extremely sparse ground observation network. Thus the complementary relationship (CR) theory lends great potential in estimating the ETa since it relies on solely routine meteorological observations. With the in-situ energy/water flux observation over the highest semiarid alpine steppe in the TP, the modifications of specific components within the CR were first implemented. We found that the symmetry of the CR could be achieved for dry regions of TP when (i) the Priestley-Taylor coefficient, (ii) the slope of the saturation vapor pressure curve and (iii) the wind function were locally calibrated by using the ETa observations in wet days, an estimate of the wet surface temperature and the Monin-Obukhov Similarity (MOS) theory, respectively. In this way, the error of the simulated ETa by the symmetric AA model could be decreased to a large extent. Besides, the asymmetric CR was confirmed in TP when the D20 above-ground and/or E601B sunken pan evaporation (Epan) were used as a proxy of the ETp. Thus daily ETa could also be estimated by coupling D20 above-ground and/or E601B sunken pans through CR. Additionally, to overcome the modification of the specific components in the CR, we also evaluated the Nonlinear-CR model and the Morton's CRAE model. The former does not need the pre-determination of the asymmetry of CR, while the latter does not require the wind speed data as input. We found that both models are also able to simulate the daily ETa well provided their parameter values have been locally calibrated. The sensitivity analysis shows that, if the measured ETa data are absence to calibrate the models' parameter values, the Nonlinear-CR model may be a particularly good way for estimating ETabecause of its mild sensitivity to the parameter

  6. Annual evapotranspiration retrieved solely from satellites' vegetation indices

    NASA Astrophysics Data System (ADS)

    Helman, David; Lensky, Itamar; Givati, Amir

    2015-04-01

    We present a simple model to retrieve annual actual evapotranspiration (ETannual) solely from satellites. The model is based on empirical relationships between vegetation indices (NDVI & EVI from MODIS) and ETannual from 16 fluxnet sites. These sites represent a wide range of plant functional types and ETannual. A multiple regression model is applied separately for (a) annuals vegetation systems (i.e., croplands and grasslands), and (b) combined annuals and perennials vegetation systems (i.e., woodlands, forests, savanna and shrublands). It explained 80% of the variance in ETannual for annuals, and 91% for combined annuals and perennials systems. We used this model to retrieve ETannual at 250 m spatial resolution for the Eastern Mediterranean from 2000 to 2013. The models estimates were highly correlated (R = 0.96, N = 7) with ETannual calculated from water catchments balances along the rainfall gradient of Israel. Models estimates were also comparable to the coarser resolution ET products of MSG (LSA-SAF MSG ETA, 3.1 km) and MODIS (MOD16, 1 km) in 148 Eastern Mediterranean basins, with a correlation coefficient (R) of 0.79 (N = 148), for both.

  7. Fuzzy-Probabilistic Calculations of Evapotranspiration

    NASA Astrophysics Data System (ADS)

    Faybishenko, B.

    2011-12-01

    Given the difficulty involved in field hydrologic and meteorological measurements, as well as a large number of empirical and semi-empirical equations, forecasting potential and actual evapotranspiration is subject to numerous uncertainties. The objective of this presentation is to illustrate the application of a conceptual-mathematical approach, based on fuzzy-probabilistic predictions of evapotranspiration and its uncertainty, and to compare the results of calculations with field evapotranspiration measurements. Calculations of potential evapotranspiration are conducted using the Bair-Robertson, Blaney-Criddle, Caprio, Hargreaves-Samani, Hamon, Jensen-Haise, Linacre, Makkink, Penman, Penman-Monteith, Priestly-Taylor, Thornthwaite, and Turc equations, and the evapotranspiration is then determined based on the modified Budyko (1974) model. As a case study, statistics from historical monthly averaged and annual climatic data from the Hanford site, Washington, USA, are used as input parameters for the RAMAS Risk Calc code. The effect of aleatory uncertainty on evapotranspiration calculations is considered by assigning probability distributions of input meteorological parameters, and the effect of epistemic (model) uncertainty is assessed by assigning different evapotranspiration models.

  8. MOLECULES IN {eta} CARINAE

    SciTech Connect

    Loinard, Laurent; Menten, Karl M.; Guesten, Rolf; Zapata, Luis A.; Rodriguez, Luis F.

    2012-04-10

    We report the detection toward {eta} Carinae of six new molecules, CO, CN, HCO{sup +}, HCN, HNC, and N{sub 2}H{sup +}, and of two of their less abundant isotopic counterparts, {sup 13}CO and H{sup 13}CN. The line profiles are moderately broad ({approx}100 km s{sup -1}), indicating that the emission originates in the dense, possibly clumpy, central arcsecond of the Homunculus Nebula. Contrary to previous claims, CO and HCO{sup +} do not appear to be underabundant in {eta} Carinae. On the other hand, molecules containing nitrogen or the {sup 13}C isotope of carbon are overabundant by about one order of magnitude. This demonstrates that, together with the dust responsible for the dimming of {eta} Carinae following the Great Eruption, the molecules detected here must have formed in situ out of CNO-processed stellar material.

  9. EVAPOTRANSPIRATION RATES AND CROP COEFFICIENTS FOR LOWBUSH BLUEBERRY (Vaccinium angustifolium)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lowbush blueberry (Vaccinium angustifolium) yield is strongly influenced by water availability; however, growers need more specific irrigation recommendations in order to optimize water use efficiency. Weighing lysimeters were used to determine actual evapotranspiration (ET) rates of lowbush bluebe...

  10. Searches for Charmless Decays B0 --> eta omega, B0 --> eta K0, B+ --> eta rho+, and B+ --> eta' pi+

    SciTech Connect

    Aubert, B

    2004-08-13

    The authors report results for measurements of the decay branching fractions of B{sup 0} to the charmless final states {eta}{omega} and {eta}K{sup 0}, and of B{sup +} to {eta}{rho}{sup +} and {eta}'{pi}{sup +}. None of these decays have been observed definitively. Measurements of the related decays B{sup +} --> {eta}K{sup +}, B{sup +} --> {eta}{pi}{sup +}, and B --> {eta}'K were published recently. Charmless decays with kaons are usually expected to be dominated by b --> s loop (''penguin'') transitions, while b --> u tree transitions are typically larger for the decays with pions and {rho} mesons. However the B --> {eta}K decays are especially interesting since they are suppressed relative to the abundant B --> {eta}'K decays due to destructive interference between two penguin amplitudes. The CKM-suppressed b --> u amplitudes may interfere significantly with penguin amplitudes, possibly leading to large direct CP violation in B{sup +} --> {eta}{rho}{sup +} and B{sup +} --> {eta}'{pi}{sup +}; numerical estimates are available in a few cases. The authors search for such direct CP violation by measuring the charge asymmetry A{sub ch} {equivalent_to} ({Gamma}{sup -} - {Gamma}{sup +})/({Gamma}{sup -} + {Gamma}{sup +}) in the rates {Gamma}{sup {+-}} = {Gamma}(B{sup {+-}} --> f{sup {+-}}), for each observed charged final state f{sup {+-}}. Charmless B decays are becoming useful to test the accuracy of theoretical predictions. Phenomenological fits to the branching fractions and charge asymmetries can be used to understand the importance of tree and penguin contributions and may provide sensitivity to the CKM angle {gamma}.

  11. Evaluating the SSEBop approach for evapotranspiration mapping with landsat data using lysimetric observations in the semi-arid Texas High Plains

    NASA Astrophysics Data System (ADS)

    Senay, G. B.; Gowda, P. H.; Bohms, S.; Howell, T. A.; Friedrichs, M.; Marek, T. H.; Verdin, J. P.

    2014-01-01

    The operational Simplified Surface Energy Balance (SSEBop) approach was applied on 14 Landsat 5 thermal infrared images for mapping daily actual evapotranspiration (ETa) fluxes during the spring and summer seasons (March-October) in 2006 and 2007. Data from four large lysimeters, managed by the USDA-ARS Conservation and Production Research Laboratory were used for evaluating the SSEBop estimated ETa. Lysimeter fields are arranged in a 2 × 2 block pattern with two fields each managed under irrigated and dryland cropping systems. The modeled and observed daily ETa values were grouped as "irrigated" and "dryland" at four different aggregation periods (1-day, 2-day, 3 day and "seasonal") for evaluation. There was a strong linear relationship between observed and modeled ETa with R2 values ranging from 0.87 to 0.97. The root mean square error (RMSE), as percent of their respective mean values, were reduced progressively with 28, 24, 16 and 12% at 1-day, 2-day, 3-day, and seasonal aggregation periods, respectively. With a further correction of the underestimation bias (-11%), the seasonal RMSE reduced from 12 to 6%. The random error contribution to the total error was reduced from 86 to 20% while the bias' contribution increased from 14 to 80% when aggregated from daily to seasonal scale, respectively. This study shows the reliable performance of the SSEBop approach on the Landsat data stream with a transferable approach for use with the recently launched LDCM (Landsat Data Continuity Mission) Thermal InfraRed Sensor (TIRS) data. Thus, SSEBop can produce quick, reliable and useful ET estimations at various time scales with higher seasonal accuracy for use in regional water management decisions.

  12. Branching Fraction Limits for B0 Decays to eta' eta, eta' pi0 and eta pi0

    SciTech Connect

    Aubert, B.

    2006-03-10

    We describe searches for decays to two-body charmless final states {eta}'{eta}, {eta}'{pi}{sup 0} and {eta}{pi}{sup 0} of B{sup 0} mesons produced in e{sup +}e{sup -} annihilation. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 232 million produced B{bar B} pairs. The results for branching fractions are, in units of 10{sup -6} (upper limits at 90% C.L.): {Beta}(B{sup 0} {yields} {eta}'{eta}) = 0.2{sub -0.5}{sup +0.7} {+-} 0.4 (< 1.7), {Beta}(B{sup 0} {yields} {eta}{pi}{sup 0}) = 0.6{sub -0.4}{sup +0.5} {+-} 0.1 (< 1.3), and {Beta}(B{sup 0} {yields} {eta}'{pi}{sup 0}) = 0.8{sub -0.6}{sup +0.8} {+-} 0.1 (< 2.1). The first error quoted is statistical and the second systematic.

  13. Eta(547) and Eta(958) Meson Photoproduction on the Proton

    SciTech Connect

    Michael Dugger

    2001-12-01

    Photoproduction of {eta} and {eta}{prime} mesons has been studied at the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) using a tagged photon beam incident on a hydrogen target with photon energies from the respective production thresholds up to 2.4 GeV. The photoproduced mesons were identified via missing mass reconstruction using recoil proton momentum and time of flight information. Data were obtained in a range of {radical}s from threshold to 2.2 GeV for each meson. In this study, differential cross-section measurements for the {gamma}p {yields} p{eta} and {gamma}p {yields} p{eta}{prime} reactions are presented, and the results compared to recent data. An isobar analysis of the differential cross-sections is performed. The predicted differential cross-sections from the isobar analysis are used to predict behavior in unmeasured regions of phase space, and to infer total cross sections. For the {gamma}p {yields} p{eta} reaction, a value of the S{sub 11}(1535) proton helicity amplitude also was extracted and compared to recent analyses. The data presented greatly extends the energy and angle coverage for differential cross-sections of {eta} photoproduction, and significantly improves the accuracy with which {eta}{prime} cross sections are known.

  14. B-meson decays to eta' rho, eta' f0, and eta' K*

    SciTech Connect

    del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Indian Inst. Tech., Guwahati /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

    2010-08-25

    We present measurements of B-meson decays to the final states {eta}{prime} {rho}, {eta}{prime} f{sub 0}, and {eta}{prime} K*, where K* stands for a vector, scalar, or tensor strange meson. We observe a significant signal or evidence for {eta}{prime} {rho}{sup +} and all the {eta}{prime}K* channels. We also measure, where applicable, the charge asymmetries, finding results consistent with no direct CP violation in all cases. The measurements are performed on a data sample consisting of 467 x 10{sup 6} B{bar B} pairs, collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. Our results favor the theoretical predictions from perturbative QCD and QCD Factorization and we observe an enhancement of the tensor K*{sub 2} (1430) with respect to the vector K*(892) component.

  15. Summary of the [eta]-meson sessions

    SciTech Connect

    Chrien, R.E.

    1993-01-01

    This summary describes the contents of the nineteen talks related to research on the [eta] meson and presented at the Workshop of Future Directions. The subjects of this area include threshold [eta] production, [eta]-nuclear spectroscopy, baryon spectroscopy, [eta] decays, facilities, and instrumentation.

  16. Summary of the {eta}-meson sessions

    SciTech Connect

    Chrien, R.E.

    1993-06-01

    This summary describes the contents of the nineteen talks related to research on the {eta} meson and presented at the Workshop of Future Directions. The subjects of this area include threshold {eta} production, {eta}-nuclear spectroscopy, baryon spectroscopy, {eta} decays, facilities, and instrumentation.

  17. The seismology of eta Bootes

    NASA Technical Reports Server (NTRS)

    Demarque, Pierre; Guenther, D. B.

    1995-01-01

    Some p-mode frequencies and other observations were used to determine the mass, the age and the helium abundance of eta Bootes. It is shown how, by direct application, the p-mode frequencies and stellar seismological tools help in constraining the physical parameters of eta Boo. The existence of mode bumping is confirmed and it is discussed how it may be used to refine the estimate of the eta Boo's age. The effect of the OPAL equation of state on the p-mode frequencies is described.

  18. Timescales of Land Surface Evapotranspiration Response

    NASA Technical Reports Server (NTRS)

    Scott, Russell; Entekhabi, Dara; Koster, Randal; Suarez, Max

    1997-01-01

    Soil and vegetation exert strong control over the evapotranspiration rate, which couples the land surface water and energy balances. A method is presented to quantify the timescale of this surface control using daily general circulation model (GCM) simulation values of evapotranspiration and precipitation. By equating the time history of evaporation efficiency (ratio of actual to potential evapotranspiration) to the convolution of precipitation and a unit kernel (temporal weighting function), response functions are generated that can be used to characterize the timescales of evapotranspiration response for the land surface model (LSM) component of GCMS. The technique is applied to the output of two multiyear simulations of a GCM, one using a Surface-Vegetation-Atmosphere-Transfer (SVAT) scheme and the other a Bucket LSM. The derived response functions show that the Bucket LSM's response is significantly slower than that of the SVAT across the globe. The analysis also shows how the timescales of interception reservoir evaporation, bare soil evaporation, and vegetation transpiration differ within the SVAT LSM.

  19. Global investigation of vegetation impact on mean annual catchment evapotranspiration

    NASA Astrophysics Data System (ADS)

    Peel, Murray C.; McMahon, Thomas A.; Finlayson, Brian L.

    2010-05-01

    Historically, relationships between catchment vegetation type, evapotranspiration and runoff have been assessed primarily through paired catchment studies. The literature contains results from over 200 of these studies from around the world but two factors limit the applicability of the results to the wider domain. Firstly, catchment areas are generally small (<10 km2). Secondly, the range of climate types is narrow, with temperate (Köppen C) and cold (Köppen D) climate types in the majority. Here we present results from a global assessment of the impact of vegetation type on mean annual catchment evapotranspiration for a large, spatially and climatically diverse dataset of 699 catchments. This assessment is based on analysis of areal precipitation, temperature, runoff, and land cover information from each catchment, which differs from the paired catchment methodology where streamflow responses to a controlled land cover change are assessed. When catchments are grouped by vegetation type, any evidence of differing vegetation impact on actual evapotranspiration will be observed through differences in mean annual actual evapotranspiration, defined as precipitation minus runoff. Stratifying catchments by climate type was observed to be important when assessing the vegetation impact on evapotranspiration. Tropical and temperate forested catchments had significantly higher median evapotranspiration (~170mm and ~130mm, respectively) than non-forested catchments. Cold forested catchments unexpectedly had significantly lower median evapotranspiration (~90mm) than non-forested catchments. No significant difference in median evapotranspiration was found between temperate evergreen and deciduous forested catchments, though sample sizes were small. Temperate evergreen needleleaf forested catchments had significantly higher median evapotranspiration than evergreen broadleaf forested catchments, though again sample sizes were small. The significant difference in median

  20. Evapotranspiration and soil heterogeneity

    SciTech Connect

    Luxmoore, R J; Sharma, M L

    1982-01-01

    In a previous computer simulation study of a grassland catchment in Oklahoma, evapotranspiration was predicted to increase up to 25% for soils with finer textures than the silt loam reference soil. Results are further analyzed to illustrate plant water responses to scaled soil physical characteristics from the simulations with the Terrestrial Ecosystem Hydrology Model. Finer soils were shown to have higher soil water capacities over wider ranges of soil matric pressures than the reference soil which increased the water supply to vegetation. The water potential and stomatal conductance of foliage were generally higher on soils with higher soil water capacities. The analysis suggests that areal variation in soil hydraulic characteristics may significantly influence areal evapotranspiration.

  1. Evapotranspiration and remote sensing

    NASA Technical Reports Server (NTRS)

    Schmugge, T. J.; Gurney, R.

    1982-01-01

    There are three things required for evapotranspiration to occur: (1) energy (580 cal/gm) for the change of phase of the water; (2) a source of the water, i.e., adequate soil moisture in the surface layer or in the root zone of the plant; and (3) a sink for the water, i.e., a moisture deficit in the air above the ground. Remote sensing can contribute information to the first two of these conditions by providing estimates of solar insolation, surface albedo, surface temperature, vegetation cover, and soil moisture content. In addition there have been attempts to estimate precipitation and shelter air temperature from remotely sensed data. The problem remains to develop methods for effectively using these sources of information to make large area estimates of evapotranspiration.

  2. B meson decays to charmless meson pairs containing eta or eta'

    SciTech Connect

    Aubert, : B.

    2009-12-14

    The authors present updated measurements of the branching fractions for B{sup 0} meson decays to {eta}K{sup 0}, {eta}{eta}, {eta}{phi}, {eta}{omega}, {eta}{prime}K{sup 0}, {eta}{prime}{eta}{prime}, {eta}{prime}, {phi}, and {eta}{prime}{omega} and branching fractions and CP-violating charge asymmetries for B{sup +} decays to {eta}{pi}{sup +}, {eta}K{sup +}, {eta}{prime}{pi}{sup +}, and {eta}{prime} K{sup +}. The data represent the full dataset of 467 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. Besides large signals for the four charged B decays modes and for B{sup 0} {yields} {eta}{prime}K{sup 0}, they find evidence for three B{sup 0} decays modes at greater than 3.0{sigma} significance. They find {Beta}(B{sup 0} {yields} {eta}K{sup 0}) = (1.15{sub -0.38}{sup +0.43} {+-} 0.09) x 10{sup -6}, {Beta}(B{sup 0} {yields} {eta}{omega}) = (0.94{sub -0.30}{sup +0.35} {+-} 0.09) x 10{sup -6}, and {Beta}(B{sup 0} {yields} {eta}{prime}{omega}) = (1.01{sub -0.38}{sup +0.46} {+-} 0.09) x 10{sup -6}, where the first (second) uncertainty is statistical (systematic). For the B{sup +} {yields} {eta}K{sup +} decay mode, they measure the charge asymmetry {Alpha}{sub ch} (B{sup +} {yields} {eta}K{sup +}) = -0.36 {+-} 0.11 {+-} 0.03.

  3. Comparison of prognostic and diagnostic approached to modeling evapotranspiration in the Nile river basin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Actual evapotranspiration (ET) can be estimated using both prognostic and diagnostic modeling approaches, providing independent yet complementary information for hydrologic applications. Both approaches have advantages and disadvantages. When provided with temporally continuous atmospheric forcing d...

  4. All Pillars Point to Eta

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Eta Carinae Starforming RegionSimulated Infrared View of Comet Tempel 1 (artist's concept)

    These false-color image taken by NASA's Spitzer Space Telescope shows the 'South Pillar' region of the star-forming region called the Carina Nebula. Like cracking open a watermelon and finding its seeds, the infrared telescope 'busted open' this murky cloud to reveal star embryos (yellow or white) tucked inside finger-like pillars of thick dust (pink). Hot gases are green and foreground stars are blue. Not all of the newfound star embryos can be easily spotted.

    Though the nebula's most famous and massive star, Eta Carinae, is too bright to be observed by infrared telescopes, the downward-streaming rays hint at its presence above the picture frame. Ultraviolet radiation and stellar winds from Eta Carinae and its siblings have shredded the cloud to pieces, leaving a mess of tendrils and pillars. This shredding process triggered the birth of the new stars uncovered by Spitzer.

    The inset visible-light picture (figure 2) of the Carina Nebula shows quite a different view. Dust pillars are fewer and appear dark because the dust is soaking up visible light. Spitzer's infrared detectors cut through this dust, allowing it to see the heat from warm, embedded star embryos, as well as deeper, more buried pillars. The visible-light picture is from the National Optical Astronomy Observatory.

    Eta Carina is a behemoth of a star, with more than 100 times the mass of our Sun. It is so massive that it can barely hold itself together. Over the years, it has brightened and faded as material has shot away from its surface. Some astronomers think Eta Carinae might die in a supernova blast within our lifetime.

    Eta Carina's home, the Carina Nebula, is located in the southern portion of our Milky Way galaxy, 10,000 light-years from Earth. This colossal cloud of gas and dust

  5. Rare semileptonic B{sub s} decays to {eta} and {eta}' mesons in QCD

    SciTech Connect

    Azizi, K.; Khosravi, R.; Falahati, F.

    2010-12-01

    We analyze the rare semileptonic B{sub s}{yields}({eta},{eta}{sup '})l{sup +}l{sup -}, (l=e,{mu},{tau}), and B{sub s}{yields}({eta},{eta}{sup '}){nu}{nu} transitions probing the ss content of the {eta} and {eta}{sup '} mesons via three-point QCD sum rules. We calculate responsible form factors for these transitions in full theory. Using the obtained form factors, we also estimate the related branching fractions and longitudinal lepton polarization asymmetries. Our results are in a good consistency with the predictions of the other existing nonperturbative approaches.

  6. Modeling Evapotranspiration in Subtropical Climate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration loss is estimated at about 80% of annual precipitation in south Florida. Accurate prediction of evapotranspiration is important during and beyond the implementation of the Comprehensive Everglades Restoration Project(CERP). In the USDA’s Everglades Agro-Hydrology Model (EAHM) the...

  7. Photoproduction of eta-mesic 3He.

    PubMed

    Pfeiffer, M; Ahrens, J; Annand, J R M; Beck, R; Caselotti, G; Cherepnya, S; Föhl, K; Fog, L S; Hornidge, D; Janssen, S; Kashevarov, V; Kondratiev, R; Kotulla, M; Krusche, B; McGeorge, J C; MacGregor, I J D; Mengel, K; Messchendorp, J G; Metag, V; Novotny, R; Rost, M; Sack, S; Sanderson, R; Schadmand, S; Thomas, A; Watts, D P

    2004-06-25

    The photoproduction of eta-mesic 3He has been investigated using the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI. The total inclusive cross section for the reaction gamma3He-->etaX has been measured for photon energies from threshold to 820 MeV. The total and angular differential coherent eta cross sections have been extracted up to energies of 745 MeV. A resonancelike structure just above the eta production threshold with an isotropic angular distribution suggests the existence of a resonant quasibound state. This is supported by studies of a competing decay channel of such a quasibound eta-mesic nucleus into pi(0)pX. A binding energy of (-4.4+/-4.2) MeV and a width of (25.6+/-6.1) MeV is deduced for the quasibound eta-mesic state in 3He. PMID:15244998

  8. Evapotranspiration crop coefficients for mixed riparian plant community and transpiration crop coefficients for Common reed, Cottonwood and Peach-leaf willow in the Platte River Basin, Nebraska-USA

    NASA Astrophysics Data System (ADS)

    Irmak, S.; Kabenge, I.; Rudnick, D.; Knezevic, S.; Woodward, D.; Moravek, M.

    2013-02-01

    SummaryApplication of two-step approach of evapotranspiration (ET) crop coefficients (Kc) to "approximate" a very complex process of actual evapotranspiration (ETa) for field crops has been practiced by water management community. However, the use of Kc, and in particular the concept of growing degree days (GDD) to estimate Kc, have not been sufficiently studied for estimation of evaporative losses from riparian vegetation. Our study is one of the first to develop evapotranspiration crop coefficient (KcET) curves for mixed riparian vegetation and transpiration (TRP) crop coefficients (KcTRP) for individual riparian species as a function GDD through extensive field campaigns conducted in 2009 and 2010 in the Platte River Basin in central Nebraska, USA. KcTRP values for individual riparian vegetation species [Common reed (Phragmites australis), Cottonwood (Populus deltoids) and Peach-leaf willow (Salix amygdaloides)] were quantified from the TRP rates obtained using scaled-up canopy resistance from measured leaf-level stomatal resistance and reference evapotranspiration. The KcET and KcTRP curves were developed for alfalfa-reference (KcrET and KcrTRP) surface. The seasonal average mixed riparian plant community KcrET was 0.89 in 2009 and 1.27 in 2010. In 2009, the seasonal average KcrTRP values for Common reed, Cottonwood and Peach-leaf willow were 0.57, 0.51 and 0.62, respectively. In 2010, the seasonal average KcrTRP were 0.69, 0.62 and 0.83 for the same species, respectively. In general, TRP crop coefficients had less interannual variability than the KcrET. Response of the vegetation to flooding in 2010 played an important role on the interannual variability of KcrET values. We demonstrated good performance and reliability of developed GDD-based KcrTRP curves by using the curves developed for 2009 to predict TRP rates of individual species in 2010. Using the KcrTRP curves developed during the 2009 season, we were able to predict the TRP rates for Common reed

  9. An annual evapotranspiration model by combining Budyko curve and complementary relationship

    NASA Astrophysics Data System (ADS)

    Han, Songjun; Tian, Fuqiang; Shao, Weiwei

    2015-04-01

    The complementary relationship and Budyko curve together describe the tight connections and feedbacks between water-energy balances and the landscape (Yang et al., 2006). The evapotranspiration models based on Budyko curve and complementary relationship are two kinds of parsimonious approaches for predicting mean annual catchment-scale evapotranspiration. Under the Budyko framework, actual evapotranspiration is partitioned from the precipitation as a functional balance between the water availability and the evaporative demand, and modified by catchment property parameter. The catchment property parameter was thought to be related to catchment landscape properties such as vegetation, soil, geological features, and rainfall distribution, etc.. The catchment properties seem change over time, and are difficult to be quantified (Roderick and Farquhar, 2011). Under the complementary relationship framework, actual evapotranspiration is estimated using only the routinely measured climatological variables, and the catchment properties were thought to be indirectly reflected by the relative magnitude of the aerodynamic and radiation terms of potential evapotranspiration because of the climate-vegetation-soil interactions. A implicit combination of the two approaches was conducted with the aim to represent the changing catchment properties using the relative magnitude of the aerodynamic and radiation terms of potential evapotranspiration. Actual evapotranspiration estimation of 99 non-humid catchments in China under varying environments was improved by this method.

  10. Measurement of branching fractions and charge asymmetries in B+ decays to eta pi+, eta K+, eta rho+, and eta' pi+, and search for B0 decays to eta K0 and eta omega.

    PubMed

    Aubert, B; Barate, R; Boutigny, D; Couderc, F; Karyotakis, Y; Lees, J P; Poireau, V; Tisserand, V; Zghiche, A; Grauges-Pous, E; Palano, A; Pappagallo, M; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morg An, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schroeder, T; Steinke, M; Boyd, J T; Burke, J P; Chevalier, N; Cottingham, W N; Kelly, M P; Cuhadar-Donszelmann, T; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Thiessen, D; Khan, A; Kyberd, P; Teodorescu, L; Blinov, A E; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bondioli, M; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Weinstein, A J R; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Wang, K; Zhang, L; Del Re, D; Hadavand, H K; Hill, E J; Macfarlane, D B; Paar, H P; Rahatlou, Sh; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Blanc, F; Bloom, P; Chen, S; Derrington, I M; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Ruddick, W O; Smith, J G; Ulmer, K A; Zhang, J; Chen, A; Eckhart, E A; Harton, J L; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q; Spaan, B; Altenburg, D; Brandt, T; Brose, J; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Maly, E; Nogowski, R; Otto, S; Petzold, A; Schott, G; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Bernard, D; Bonneaud, G R; Grenier, P; Schrenk, S; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Marks, J; Uwer, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Nikolich, M B; Taylor, G P; Charles, M J; Grenier, G J; Mallik, U; Cochran, J; Crawley, H B; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Yi, J; Arnaud, N; Davier, M; Giroux, X; Grosdidier, G; Höcker, A; Le Diberder, F; Lepeltier, V; Lutz, A M; Petersen, T C; Pierini, M; Plaszczynski, S; Rodier, S; Roudeau, P; Schune, M H; Stocchi, A; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Chavez, C A; Coleman, J P; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Parry, R J; Payne, D J; Touramanis, C; Cormack, C M; Di Lodovico, F; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; Green, M G; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hodgkinson, M C; Lafferty, G D; Naisbit, M T; Williams, J C; Chen, C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Koeneke, K; Sciolla, G; Sekula, S J; Taylor, F; Yamamoto, R K; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Taras, P; Nicholson, H; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Snoek, H L; Wilden, L; Jessop, C P; Losecco, J M; Allmendinger, T; Benelli, G; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonyan, R; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Lu, M; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; Del Buono, L; de la Vaissière, Ch; Hamon, O; John, M J J; Leruste, Ph; Malclès, J; Ocariz, J; Roos, L; Therin, G; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Biasini, M; Covarelli, R; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bucci, F; Calderini, G; Carpinelli, M; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Simi, G; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lau, Y P; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Tehrani, F Safai; Voena, C; Christ, S; Schröder, H; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Gopal, G P; Olaiya, E O; Wilson, F F; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P-F; Graziani, G; Hamel de Monchenault, G; Kozanecki, W; Legendre, M; London, G W; Mayer, B; Vasseur, G; Yèche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Wilson, J R; Yumiceva, F X; Abe, T; Allen, M T; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Claus, R; Convery, M R; Cristinziani, M; Dingfelder, J C; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Fan, S; Field, R C; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hast, C; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Mohapatra, A K; Muller, D R; O'grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Soha, A; Stelzer, J; Strube, J; Su, D; Sullivan, M K; Thompson, J M; Va'vra, J; Wagner, S R; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Martinez-Vidal, F; Panvini, R S; Banerjee, Sw; Bhuyan, B; Brown, C M; Fortin, D; Hamano, K; Jackson, P D; Kowalewski, R; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Band, H R; Chen, X; Cheng, B; Dasu, S; Datta, M; Eichenbaum, A M; Flood, K T; Graham, M; Hollar, J J; Johnson, J R; Kutter, P E; Li, H; Liu, R; Mellado, B; Mihalyi, A; Pan, Y; Prepost, R; Tan, P; von Wimmersperg-Toeller, J H; Wu, J; Wu, S L; Yu, Z; Greene, M G; Neal, H

    2005-09-23

    We present measurements of branching fractions and charge asymmetries for six B-meson decay modes with an eta or eta(') meson in the final state. The data sample corresponds to 232 x 10(6) BB pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) B Factory at SLAC. We measure the branching fractions (in units of 10(-6)): B(B+ -->eta pi(+))=5.1+/-0.6+/-0.3, B(B+ etaK+)=3.3+/-0.6+/-0.3, B(B0-->etaK0)=1.5+/-0.7+/-0.1 (<2.5 at 90% C.L.), B(B+-->eta rho(+))=8.4+/-1.9+/-1.1, B(B0-->eta omiga)=1.0+/-0.5+/-0.2 (<1.9 at 90% C.L.), and B(B+-->eta(')pi(+))=4.0+/-0.8+/-0.4, where the first uncertainty is statistical and second systematic. For the charged modes we also determine the charge asymmetries, all found to be compatible with zero. PMID:16197132

  11. Recent results on eta and eta-prime photoproduction on the proton

    SciTech Connect

    Barry Ritchie

    2004-06-01

    The experimental situation on eta and eta' photoproduction on the proton is reviewed, emphasizing progress made since 2001. New preliminary results for eta' photoproduction on the proton from Jefferson Lab are presented. Experimental results are compared with several theoretical approaches, with an emphasis on consequences for understanding baryon spectroscopy.

  12. Experimental test accelerator (ETA) II

    SciTech Connect

    Fessenden, T.J.; Atchison, W.L.; Birx, D.L.

    1981-03-06

    The Experimental Test Accelerator (ETA) is designed to produce a 10 kAmp electron beam at an energy of 4.5 MeV in 40 nsec pulses at an average rate of 2 pps. The accelerator also operates in bursts of 5 pulses spaced by as little as one millisec at an average rate of 5 pps. The machine is currently operating near 80% of its design values and has accumulated over 2.5 million pulses - mostly at a rate of one pps. The plasma cathode electron source, the remainder of the accelerator, and the operating characteristics of the machine are discussed.

  13. Annual evapotranspiration retrieved from satellite vegetation indices for the eastern Mediterranean at 250 m spatial resolution

    NASA Astrophysics Data System (ADS)

    Helman, D.; Givati, A.; Lensky, I. M.

    2015-11-01

    We present a model to retrieve actual evapotranspiration (ET) from satellites' vegetation indices (Parameterization of Vegetation Indices for ET estimation model, or PaVI-E) for the eastern Mediterranean (EM) at a spatial resolution of 250 m. The model is based on the empirical relationship between satellites' vegetation indices (normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) from MODIS) and total annual ET (ETAnnual) estimated at 16 FLUXNET sites, representing a wide range of plant functional types and ETAnnual. Empirical relationships were first examined separately for (a) annual vegetation systems (i.e. croplands and grasslands) and (b) systems with combined annual and perennial vegetation (i.e. woodlands, forests, savannah and shrublands). Vegetation indices explained most of the variance in ETAnnual in those systems (71 % for annuals, and 88 % for combined annual and perennial systems), while adding land surface temperature data in a multiple-variable regression and a modified version of the Temperature and Greenness model did not result in better correlations (p > 0.1). After establishing empirical relationships, PaVI-E was used to retrieve ETAnnual for the EM from 2000 to 2014. Models' estimates were highly correlated (R = 0.92, p < 0.01) with ETAnnual calculated from water catchment balances along rainfall gradient of the EM. They were also comparable to the coarser-resolution ET products of the Land Surface Analysis Satellite Applications Facility (LSA-SAF MSG ETa, 3.1 km) and MODIS (MOD16, 1 km) at 148 EM basins with R of 0.75 and 0.77 and relative biases of 5.2 and -5.2 %, respectively (p < 0.001 for both). In the absence of high-resolution (< 1 km) ET models for the EM the proposed model is expected to contribute to the hydrological study of this region, assisting in water resource management, which is one of the most valuable resources of this region.

  14. Resolving Eta Carinae and It's Ejecta

    NASA Technical Reports Server (NTRS)

    Gull Theodore R.; Oegerle, William R. (Technical Monitor)

    2002-01-01

    Imaging spectroscopy of Eta Carinae and the Homunculus has led to considerable new insight on the excitation mechanisms, the elemental abundances, and the physical properties of ejecta from Eta Carinae. With HST/STIS we have been able to resolve the central source into many substructures.

  15. Eta Carinae: an Astrophysical Laboratory

    NASA Astrophysics Data System (ADS)

    Nielsen, Krister E.; Gull, Theodore R.

    2009-05-01

    Eta Carinae provides a unique example to investigate a massive star in a late evolutionary phase and how CNO-processed material is ejected and mixed with the interstellar medium. The absorbing gas surrounding Eta Carinae (η Car) shows similar characteristics to the intervening gas in spectra of gamma ray burst progenitors. Consequently, the η Car spectrum may provide clues about the nature of other extreme objects such as hypernovae and supernova impostors. In the 1840s, η Car underwent a massive ejection, which was repeated to a lesser extent in the 1890s. Today we see the Homunculus, a bipolar expanding neutral shell, and the Little Homunculus, an interior, spectroscopically time-variable, ionized structure. The η Car system is ideal as a laboratory for absorption and emission line spectroscopy. In the line-of-sight towards η Car, multiple narrow absorption lines are observed from environments with densities around 107 cm- 3 and temperatures ranging from 60 to 7000 K. Thousands of neutral/singly ionized metal lines are identified, in addition to molecular lines in species such as H2, CH, OH and NH. The input from the laboratory spectroscopy community has furthered the analysis of η Car. Future observations of η Car in the infrared through radio wavelength region will enable new detections of atomic and molecular transitions, most notably of hydrides and nitrides. We will demonstrate how experimentally derived atomic data have improved our spectral analysis, and illuminate where future work is needed.

  16. The Enigmatic Eta Carinae: Current Status

    NASA Astrophysics Data System (ADS)

    Hillier, D. J.

    2008-06-01

    Eta Carinae is one of the most famous Luminous Blue Variables but also one of the least understood. Our understanding of η Carinae is severely hindered by the dense wind of the primary star, the influence of a binary companion, the complex circumstellar environment, the asymmetric nature of the mass loss, and the presence of an ``intrinsic" coronagraph which biases our view of Eta Carinae. With the advent of extensive new Hubble Space Telescope data, X-ray data, and ground-based spectroscopic and interferometric observations of Eta Carinae, there has been a dramatic increase in observational material which can be used to place constraints on Eta Carinae and its Homunculus. We summarize recent results, and highlight how recent data is providing new insight into the nature of Eta Carinae.

  17. Pseudoscalar glueball and {eta}-{eta}{sup '} mixing

    SciTech Connect

    Mathieu, Vincent; Vento, Vicente

    2010-02-01

    We have performed a dynamical analysis of the mixing in the pseudoscalar channel with the goal of understanding the existence and behavior of the pseudoscalar glueball. Our philosophy has not been to predict precise values of the glueball mass but to exploit an adequate effective theory to the point of breaking and to analyze which kind of mechanisms restore compatibility with data. Our study has led to analytical solutions which allow a clear understanding of the phenomena. The outcome of our calculation leads to a large mass glueball M{sub {Theta}>}2000 MeV, to a large glue content of the {eta}{sup '}, and to mixing angles in agreement with previous numerical studies.

  18. Observation of B-->eta'K* and evidence for B+-->eta'rho+.

    PubMed

    Aubert, B; Barate, R; Bona, M; Boutigny, D; Couderc, F; Karyotakis, Y; Lees, J P; Poireau, V; Tisserand, V; Zghiche, A; Grauges, E; Palano, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Gill, M S; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Wenzel, W A; del Amo Sanchez, P; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schroeder, T; Steinke, M; Boyd, J T; Burke, J P; Cottingham, W N; Walker, D; Cuhadar-Donszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Saleem, M; Sherwood, D J; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Best, D S; Bondioli, M; Bruinsma, M; Chao, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Wang, K; Zhang, L; Hadavand, H K; Hill, E J; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dvoretskii, A; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Ruddick, W O; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Zeng, Q; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Petzold, A; Spaan, B; Brandt, T; Klose, V; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Grenier, P; Latour, E; Thiebaux, Ch; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D J; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Flack, R L; Nash, J A; Nikolich, M B; Panduro Vazquez, W; Behera, P K; Chai, X; Charles, M J; Mallik, U; Meyer, N T; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gritsan, A V; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Davier, M; Grosdidier, G; Höcker, A; Le Diberder, F; Lepeltier, V; Lutz, A M; Oyanguren, A; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Stocchi, A; Wang, W F; Wormser, G; Cheng, C H; Lange, D J; Wright, D M; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; Di Lodovico, F; Menges, W; Sacco, R; Cowan, G; Flaecher, H U; Hopkins, D A; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Wren, A C; Brown, D N; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; Naisbit, M T; Williams, J C; Yi, J I; Chen, C; Hulsbergen, W D; Jawahery, A; Lae, C K; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Saremi, S; Staengle, H; Cowan, R; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Kim, H; McLachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Raven, G; Snoek, H L; Jessop, C P; Losecco, J M; Allmendinger, T; Benelli, G; Gan, K K; Honscheid, K; Hufnagel, D; Jackson, P D; Kagan, H; Kass, R; Rahimi, A M; Ter-Antonyan, R; Wong, Q K; Blount, N L; Brau, J; Frey, R; Igonkina, O; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Benayoun, M; Chauveau, J; Briand, H; David, P; Del Buono, L; de la Vaissière, Ch; Hamon, O; Hartfiel, B L; John, M J J; Leruste, Ph; Malclès, J; Ocariz, J; Roos, L; Therin, G; Gladney, L; Panetta, J; Biasini, M; Covarelli, R; Angelini, C; Batignani, G; Bettarini, S; Bucci, F; Calderini, G; Carpinelli, M; Cenci, R; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Haire, M; Judd, D; Wagoner, D E; Biesiada, J; Danielson, N; Elmer, P; Lau, Y P; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; Del Re, D; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Safai Tehrani, F; Voena, C; Ebert, M; Schröder, H; Waldi, R; Adye, T; De Groot, N; Franek, B; Olaiya, E O; Wilson, F F; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Hamel de Monchenault, G; Kozanecki, W; Legendre, M; Vasseur, G; Yèche, Ch; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Claus, R; Coleman, J P; Convery, M R; Cristinziani, M; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Halyo, V; Hast, C; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, P; Leith, D W G S; Li, S; Luitz, S; Luth, V; Lynch, H L; Macfarlane, D B; Marsiske, H; Messner, R; Muller, D R; O'grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Va'vra, J; van Bakel, N; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Roat, C; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Satpathy, A; Schilling, C J; Schwitters, R F; Izen, J M; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Dittongo, S; Lanceri, L; Vitale, L; Azzolini, V; Martinez-Vidal, F; Banerjee, Sw; Bhuyan, B; Brown, C M; Fortin, D; Hamano, K; Kowalewski, R; Nugent, I M; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Pappagallo, M; Band, H R; Chen, X; Cheng, B; Dasu, S; Datta, M; Flood, K T; Hollar, J J; Kutter, P E; Mellado, B; Mihalyi, A; Pan, Y; Pierini, M; Prepost, R; Wu, S L; Yu, Z; Neal, H

    2007-02-01

    We present an observation of B-->eta'K*. The data sample corresponds to 232x10(6) BB[over ] pairs collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the Stanford Linear Accelerator Center. We measure the branching fractions (in units of 10(-6)) B(B(0)-->eta'K*0)=3.8+/-1.1+/-0.5 and B(B+-->eta'K*+)=4.9(1.7)(+1.9)+/-0.8, where the first error is statistical and the second systematic. A simultaneous fit results in the observation of B-->eta'K* with B(B-->eta'K*)=4.1(-0.9)(+1.0)+/-0.5. We also search for B-->eta'rho and eta'f(0)(980)(f(0)-->pi+pi-) with results and 90% confidence level upper limits B(B+-->eta'rho+)=8.7(-2.8-1.3)(+3.1+2.3) (<14), B(B(0)-->eta'rho0)<3.7, and B(B(0)-->eta'f(0)(980)(f(0)-->pi+pi-))<1.5. Charge asymmetries in the channels with significant yields are consistent with zero. PMID:17358844

  19. The Uncloaking of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.

    2000-01-01

    Space Telescope Imaging Spectrograph spectroscopy has revealed much new detail of the ejecta thrown out of Eta Carinae. We have now accomplished eight visits of the star and the Homunculus using the STIS with a 52" x 0.1" aperture and with spectral coverage from 1640A to 10400A. Moreover we now have FUV observations with the STIS and with FUSE. From the FUSE and FUV observations, we see strong evidence for a hot companion star, likely in agreement with the binaricity of the spectrum in the near red. From the STIS observations, we see evidence of much substructure of the ejecta, ranging from the fast moving strings noted by Kirstin Weis, the outer emission nebula, to the Homunculus lobes and a disk. Deep within, we find a bipolar structure, the Integral Nebula and finally close to the star, a small ionized gas region that shows evidence of the stellar wind being resolved from the central source(s).

  20. Eta Carinae: A Demanding Mistress

    NASA Technical Reports Server (NTRS)

    Gull, Theodore

    2012-01-01

    In the 1840's a southern star, Eta Argus, brightened to rival Sirius for nearly a decade, then faded. Today, we see the Homunculus, an hourglass figure with tutu, a dusty shell exceeding 12 solar masses expanding outward at 500 km/s. Many observers have systematically studied the massive binary total shrouded by interacting winds and its ejecta. More recently 3-D wind-wind collision models have begun to explain the extended structures resolved by Hubble Space Telescope. Now Herschel Space Observatory infrared scans are revealing wind interaction emissions and complex molecules left over from the dust that formed out of gas originally overabundant in nitrogen and greatly-depleted in oxygen and carbon. Many questions remain to be answered: What is the dust that formed in the 1840s event? What are the end states of the two massive companions ... SN, GRB, Hypernova? and When

  1. Phenomenology of some rare and forbidden. eta. -decays

    SciTech Connect

    Herczeg, P.

    1990-01-01

    We discuss the contribution from possible new physics to the decays {eta} {yields} {mu}{sup +}{mu}{sup {minus}}, {eta} {yields} e{sup +}e{sup {minus}}, {eta} {yields} {mu}e and {eta} {pi}{mu}e, and assess the sensitivities required for experimental studies of these decays to extend our knowledge about the new interactions. 61 refs.

  2. THE ENVIRONMENTAL TECHNOLOGIES ACCEPTANCE (ETA) PROGRAM

    SciTech Connect

    Christina B. Behr-Andres

    2001-04-01

    The Environmental Technologies Acceptance (ETA) Program at the Energy and Environmental Research Center (EERC) is intended to advance the development, commercial acceptance, and timely deployment of selected private sector technologies for the cleanup of sites in the nuclear defense complex as well as the greater market. As shown in Table 1, this cooperative agreement funded by the National Energy Technology Laboratory (NETL) consists of three tasks: Technology Selection, Technology Development, and Technology Verification. As currently conceived, the ETA will address the needs of as many technologies as appropriate under its current 3-year term. This report covers activities during the first 6 months of the 3-year ETA program.

  3. Eta Carinae and Its Ejecta, the Homunculus

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.

    2014-01-01

    Eta Carinae (Eta Car), its interacting winds and historical ejecta provide an unique astrophysical laboratory that permits addressing a multitude of questions ranging from stellar evolution, colliding winds, chemical enrichment, nebular excitation to the formation of molecules and dust. Every 5.54 years, Eta Car changes from high excitation to several-months-long low excitation caused by modulation of the massive interacting winds due to a very eccentric binary orbit. The surrounding Homunculus (Figure 1) and Little Homunculus, thrown out in the 1840s Great Eruption and the 1890s Lesser Eruption, respond to the changing flux, providing clues to many physical phenomena of great interest to astrophysicists.

  4. Investigation of the electromagnetic structure of. eta. and. eta. prime mesons by two-photon interactions

    SciTech Connect

    Aihara, H.; Alston-Garnjost, M.; Avery, R.E.; Barbaro-Galtieri, A.; Barker, A.R.; Barnett, B.A.; Bauer, D.A.; Bay, A.; Bobbink, G.J.; Buchanan, C.D.; Buijs, A.; Caldwell, D.O.; Chao, H.; Chun, S.; Clark, A.R.; Cowan, G.D.; Crane, D.A.; Dahl, O.I.; Daoudi, M.; Derby, K.A.; Eastman, J.J.; Eberhard, P.H.; Edberg, T.K.; Eisner, A.M.; Erne, F.C.; Fairfield, K.H.; Hauptman, J.M.; Hofmann, W.; Hylen, J.; Kamae, T.; Kaye, H.S.; Kenney, R.W.; Khacheryan, S.; Kofler, R.R.; Langeveld, W.G.J.; Layter, J.G.; Lin, W.T.; Linde, F.L.; Loken, S.C.; Lu, A.; Lynch, G.R.; Madaras, R.J.; Magnuson, B.D.; Masek, G.E.; Mathis, L.G.; Matthews, J.A.J.; Maxfield, S.J.; Miller, E.S.; Moses, W.; Nygren, D.R.; Oddone, P.J.; Paar, H.P.; Park, S.K.; Pellett, D.E.; Pripstein, M.; Ronan, M.T.; Ross, R.R.; Rouse, F.R.; Schwitkis, K.A.; Sens, J.C.; Shapiro, G.; Shen, B.C.; Smith, J.R.; Steinman, J.S.; Stephens, R.W.; Stevenson, M.L.; Stork, D.H.; Strauss, M.G.; Sullivan, M.K.; Takahashi, T.; Toutounchi, S.; van Tyen, R.; TPC /Two-Gamma Collaboration

    1990-01-08

    The TPC/Two-Gamma facility at the SLAC {ital e}{sup +}{ital e}{sup {minus}} storage ring PEP was used to study the reactions {gamma}{gamma}{sup *}{r arrow}{eta} and {gamma}{gamma}{sup *}{r arrow}{eta}{prime}. The {eta}{gamma}{sup *}{gamma} and {eta}{prime}{gamma}{sup *}{gamma} transition form factors were measured as functions of {ital Q}{sup 2}, the negative of the invariant mass squared of the tagged photon, in the range 0.1{lt}{ital Q}{sup 2}{lt}7 GeV{sup 2}. These determinations of the electromagnetic structure of the {eta} and {eta}{prime} mesons are consistent with both vector-meson dominance and QCD. They also provide new measurements of the pseudoscalar mixing angle and decay constants.

  5. Minute Temperature Fluctuations Detected in Eta Bootis

    NASA Astrophysics Data System (ADS)

    1994-11-01

    , even in the very brightest stars. Faced with this problem, the Danish/ESO group came up with an entirely new method. It relies on the fact that the oscillations are sound waves which deposit energy in the various stellar layers and therefore intermittently heat the star very slightly. For example, each mode changes the temperature on the surface of the Sun by about 0.005 degrees during the oscillation. But how to measure such small temperature changes? It turns out that this is possible by recording the strengths of the spectral lines, specifically, the absorption lines due to hydrogen. Their strengths change slightly with the changes in temperature (see Appendix). Although this is still a very small effect, it should be easier to measure than the velocity shifts. Yes, Eta Bootis does! To test their method, the astronomers used the ESO 3.5-metre New Technology Telescope (NTT) with the ESO Multi-Mode Instrument (EMMI) to observe a bright star for a few hours. This was too short to detect actual oscillations, but it did show that the technique works: it was in principle possible to measure the temperature accurately enough. The target for the real observations was the 2.68-magnitude, naked-eye star Eta Bootis (Greek letter "eta"). It has the common name of Muphrid and is located just north of the celestial equator in Bootes, one of the oldest constellation names still in use (it was mentioned already in the Odyssey). This particular star is somewhat more evolved and bigger than the Sun and, according to stellar theory, should have stronger oscillations than the Sun, hence increasing the chance that they could be detected. The observations were performed with the 2.5-metre Nordic Optical Telescope (NOT) during six, mostly clear nights in April 1994. A careful data analysis has now shown that the temperature of Eta Bootis is indeed changing periodically, around a mean value of about 6000 K. It seems to be oscillating in at least ten different modes simultaneously, with

  6. Evapotranspiration studies for protective barriers: Experimental plans

    SciTech Connect

    Link, S.O.; Waugh, W.J.

    1989-11-01

    This document describes a general theory and experimental plans for predicting evapotranspiration in support of the Protective Barrier Program. Evapotranspiration is the combined loss of water from plants and soil surfaces to the atmosphere. 45 refs., 1 fig., 4 tabs.

  7. Potential Evapotranspiration on Tutuila, American Samoa

    USGS Publications Warehouse

    Izuka, Scott K.; Giambelluca, Thomas W.; Nullet, Michael A.

    2005-01-01

    Data from nine widely distributed climate stations were used to assess the distribution of potential evapotranspiration on the tropical South Pacific island of Tutuila, American Samoa. Seasonal patterns of climate data in this study differed in detail from available long-term data because the monitoring period of each station in this study was only 1 to 5 years, but overall climate conditions during the monitoring period (1999-2004) are representative of normal conditions. Potential evapotranspiration shows a diurnal pattern. On average, potential evapotranspiration in the daytime, when net radiation is the dominant controlling factor, constitutes 90 percent or more of the total daily potential evapotranspiration at each station. Positive heat advection from the ocean contributes to potential evapotranspiration at at least one station, and possibly other stations, in this study. Seasonal variation of potential evapotranspiration is linked to seasonal daylight duration. Spatial variation of potential evapotranspiration, however, is linked primarily to orographic cloud cover. Potential evapotranspiration on Tutuila is lowest in the interior of the island, where rainfall is higher, cloud cover is more frequent, and net radiation is lower than along the coasts. Potential evapotranspiration is highest along the southern and eastern coasts of the island, where rainfall is lower and cloud cover less frequent. The gradient from areas of high to low potential evapotranspiration is steepest in November and December, when island-wide potential evapotranspiration is highest, and less steep in June and July, when island-wide potential evapotranspiration is lowest. Comparison of potential evapotranspiration to rainfall indicates that evapotranspiration processes on Tutuila have the potential to remove from 23 to 61 percent of the water brought by rainfall. In lower-rainfall coastal locations, potential evapotranspiration can be 50 percent or more of rainfall, whereas in higher

  8. Search For {eta}-Bound Nuclei

    SciTech Connect

    Machner, H.

    2011-10-24

    The {eta} meson can be bound to atomic nuclei. Experimental search is discussed in the form of final state interaction for the reactions dp{yields}{sup 3}He{eta} and dd{yields}{sup 4}He{eta}. For the latter case tensor polarized deuterons were used in order to extract the s-wave strength. For both reactions complex scattering lengths are deduced: In a two-nucleon transfer reaction under quasi-free conditions, p{sup 27}Al{yields}{sup 3}HeX, was investigated. The system X can be the bound {sup 25}Mg x {eta} at rest. When a possible decay of an intermediate N{sup *}(1535) is required, a highly significant bump shows up in the missing mass spectrum. The data give for a bound state a binding energy of 13.3{+-}1.6 MeV and a width of {sigma} = 4.4{+-}1.3 MeV.

  9. Evapotranspiration (ET) covers.

    PubMed

    Rock, Steve; Myers, Bill; Fiedler, Linda

    2012-01-01

    Evapotranspiration (ET) cover systems are increasingly being used at municipal solid waste (MSW) landfills, hazardous waste landfills, at industrial monofills, and at mine sites. Conventional cover systems use materials with low hydraulic permeability (barrier layers) to minimize the downward migration of water from the surface to the waste (percolation), ET cover systems use water balance components to minimize percolation. These cover systems rely on soil to capture and store precipitation until it is either transpired through vegetation or evaporated from the soil surface. Compared to conventional membrane or compacted clay cover systems, ET cover systems are expected to cost less to construct. They are often aesthetic because they employ naturalized vegetation, require less maintenance once the vegetative system is established, including eliminating mowing, and may require fewer repairs than a barrier system. All cover systems should consider the goals of the cover in terms of protectiveness, including the pathways of risk from contained material, the lifecycle of the containment system. The containment system needs to be protective of direct contact of people and animals with the waste, prevent surface and groundwater water pollution, and minimize release of airborne contaminants. While most containment strategies have been based on the dry tomb strategy of keeping waste dry, there are some sites where adding or allowing moisture to help decompose organic waste is the current plan. ET covers may work well in places where complete exclusion of precipitation is not needed. The U.S. EPA Alternative Cover Assessment Program (ACAP), USDOE, the Nuclear Regulatory Commission, and others have researched ET cover design and efficacy, including the history of their use, general considerations in their design, performance, monitoring, cost, current status, limitations on their use, and project specific examples. An on-line database has been developed with information

  10. ETA-II accelerator upgrades

    SciTech Connect

    Nilson, D.G.; Deadrick, F.J.; Hibbs, S.M.; Sampayan, S.E.; Petersen, D.E.

    1991-09-01

    We discuss recent improvements to the ETA-II linear induction electron accelerator. The accelerator's cells have been carefully reconditioned to raise the maximum accelerating gap voltage from approximately 100 kV to 125 kV. Insulators of Rexolite plastic in a new zero-gap'' arrangement replaced the alumina originals after several alternative materials were investigated. A new multi-cable current feed system will be used to eliminate pulse reflection interactions encountered in earlier experiments. Improved alignment fixtures have been installed to help minimize beam perturbation due to poorly aligned intercell magnets between 10-cell groups. A stretched wire alignment technique (SWAT) has been utilized to enhance overall magnetic alignment, and to characterize irreducible alignment errors. These changes are in conjunction with an expansion of the accelerator from a 20-cell to a 60-cell configuration. When completed, the upgraded accelerator is expected to deliver 2.5 kA of electron beam current at 7.5 MeV in bursts of up to fifty 70-ns pulses at a 5-kHz repetition rate. A 5.5-meter-long wiggler will convert the energy into 3-GW microwave pulses at 140 GHz for plasma heating experiments in the Microwave Tokamak Experiment (MTX).

  11. ETA-II accelerator upgrades

    SciTech Connect

    Nilson, D.G.; Deadrick, F.J.; Hibbs, S.M.; Sampayan, S.E.; Petersen, D.E.

    1991-09-01

    We discuss recent improvements to the ETA-II linear induction electron accelerator. The accelerator`s cells have been carefully reconditioned to raise the maximum accelerating gap voltage from approximately 100 kV to 125 kV. Insulators of Rexolite plastic in a new ``zero-gap`` arrangement replaced the alumina originals after several alternative materials were investigated. A new multi-cable current feed system will be used to eliminate pulse reflection interactions encountered in earlier experiments. Improved alignment fixtures have been installed to help minimize beam perturbation due to poorly aligned intercell magnets between 10-cell groups. A stretched wire alignment technique (SWAT) has been utilized to enhance overall magnetic alignment, and to characterize irreducible alignment errors. These changes are in conjunction with an expansion of the accelerator from a 20-cell to a 60-cell configuration. When completed, the upgraded accelerator is expected to deliver 2.5 kA of electron beam current at 7.5 MeV in bursts of up to fifty 70-ns pulses at a 5-kHz repetition rate. A 5.5-meter-long wiggler will convert the energy into 3-GW microwave pulses at 140 GHz for plasma heating experiments in the Microwave Tokamak Experiment (MTX).

  12. Eta Squared and Partial Eta Squared as Measures of Effect Size in Educational Research

    ERIC Educational Resources Information Center

    Richardson, John T. E.

    2011-01-01

    Eta squared measures the proportion of the total variance in a dependent variable that is associated with the membership of different groups defined by an independent variable. Partial eta squared is a similar measure in which the effects of other independent variables and interactions are partialled out. The development of these measures is…

  13. Effect of {eta}-{eta}{sup '} mixing on D{yields}PV decays

    SciTech Connect

    Bhattacharya, Bhubanjyoti; Rosner, Jonathan L.

    2010-08-01

    Charmed meson decays to a light pseudoscalar (P) and light vector (V) meson are analyzed taking account of {eta}-{eta}{sup '} mixing. A frequently-used octet-singlet mixing angle of 19.5 degree sign is compared with a value of 11.7 degree sign favored by a recent analysis of D{yields}PP decays.

  14. Chiral corrections to the anomalous 2. gamma. decays of. pi. sup 0 ,. eta. and. eta. prime

    SciTech Connect

    Issler, D.

    1990-11-01

    To any order in chiral perturbation theory, the anomalous Wess-Zumino term is shown to generate only chirally invariant counterterms. Explicit examples of 0(p{sub 6}) terms generated by one-loop graphs are given, some of which are relevant to the two-photon decays of {pi}{sup o}, {eta} and {eta}{prime}.

  15. Observation of B to eta' K* and Evidence for B+ to eta' rho+

    SciTech Connect

    Aubert, B

    2006-09-26

    The authors presented an observation of B {yields} {eta}{prime}K*. The data sample corresponds to 232 million B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. They measure the branching fractions (in units of 10{sup -6}) {Beta}(B{sup 0} {yields} {eta}{prime}K*{sup 0}) = 3.8 {+-} 1.1 {+-} 0.5 and {Beta}(B{sup +} {yields} {eta}{prime}K*{sup +}) = 4.9{sub -1.7}{sup +1.9} {+-} 0.8, where the first error is statistical and the second systematic. A simultaneous fit results in the observation of B {yields} {eta}{prime}K* with {Beta}(B {yields} {eta}{prime}K*) = 4.1{sub -0.9}{sup +1.0} {+-} 0.5. They also search for B {yields} {eta}{prime}{rho} and {eta}{prime} f{sub 0}(980)(f{sub 0} {yields} {pi}{sup +}{pi}{sup -}) with results and 90% confidence level upper limits {Beta}(B{sup +} {yields} {eta}{prime}{rho}{sup +}) = 8.7{sub -2.8-1.3}{sup +3.1+2.3} (< 14), {Beta}(B{sup 0} {yields} {eta}{prime}{rho}{sup 0}) < 3.7, and {Beta}(B{sup 0} {yields} {eta}{prime} f{sub 0}(980)(f{sub 0} {yields} {pi}{sup +}{pi}{sup -})) < 1.5. Charge asymmetries in the channels with significant yields are consistent with zero.

  16. Eta Carinae: Orientation of The Orbital Plane

    NASA Technical Reports Server (NTRS)

    Gull, T. R.; Nielsen, K. E.; Ivarsson, S.; Corcoran, M. F.; Verner, E.; Hillier, J. D.

    2006-01-01

    Evidence continues to build that Eta Carinae is a massive binary system with a hidden hot companion in a highly elliptical orbit. We present imaging and spectroscopic evidence that provide clues to the orientation of the orbital plane. The circumstellar ejecta, known as the Homunculus and Little Homunculus, are hourglass-shaped structures, one encapsulated within the other, tilted at about 45 degrees from the sky plane. A disk region lies between the bipolar lobes. Based upon their velocities and proper motions, Weigelt blobs B, C and D, very bright emission clumps 0.1 to 0.3" Northwest from Eta Carinae, lie in the disk. UV flux from the hot companion, Eta Car B, photoexcites the Weigelt blobs. Other clumps form a complete chain around the star, but are not significantly photoexcited. The strontium filament, a 'neutral' emission structure, lies in the same general direction as the Weigelt blobs and exhibits peculiar properties indicative that much mid-UV, but no hydrogen-ionizing radiation impinges on this structure. It is shielded by singly-ionized iron. P Cygni absorptions in Fe I I lines, seen directly in line of sight from Eta Carinae, are absent in the stellar light scattered by the Weigelt blobs. Rather than a strong absorption extending to -600 km/s, a low velocity absorption feature extends from -40 to -150 km/s. No absorbing Fe II exists between Eta Carinae and Weigelt D, but the outer reaches of the wind are intercepted in line of sight from Weigelt D to the observer. This indicates that the UV radiation is constrained by the dominating wind of Eta Car A to a small cavity carved out by the weaker wind of Eta Car B. Since the high excitation nebular lines are seen in the Weigelt blobs at most phases, the cavity, and hence the major axis of the highly elliptical orbit, must lie in the general direction of the Weigelt blobs. The evidence is compelling that the orbital major axis of Eta Carinae is projected at -45 degrees position angle on the sky. Moreover

  17. Eta Carinae, the most brutal binary bipolar

    NASA Astrophysics Data System (ADS)

    Icke, V.

    Eta Carinae, one of the most extreme and fascinating objects in our Galaxy, is a supermassive interacting binary at the centre of a bipolar nebula, expanding at about 500 km s^{-1}. Finding the mechanisms behind Eta's appearance, behaviour and evolution is the main goal of this investigation. I have constructed a large series of numerical models of dual-wind binary stars, of which I present here one that probably comes close to the Eta Carinae parameters. I presume that the gaseous `skirt' surrounding Eta is an equatorial `excretion disk' formed by the interacting binary, that the bipolar `Homunculus' nebula above and below this plane is due to the collision between the material ejected in the 1840 `Giant Eruption' and the disk, and the `Little Homunculus' similarly in the smaller 1890 eruption. I have extensively explored the general types of flow pattern expected here. My Theory Group is working towards 3D radiation-hydrodynamics simulations for quantitative comparison with Eta, which many believe to be a key to understanding a variety of hitherto unexplained phenomena in and around massive stars, be they binary or single.

  18. Evaluating a satellite-based seasonal evapotranspiration product and identifying its relationship with other satellite-derived products and crop yield: A case study for Ethiopia

    NASA Astrophysics Data System (ADS)

    Tadesse, Tsegaye; Senay, Gabriel B.; Berhan, Getachew; Regassa, Teshome; Beyene, Shimelis

    2015-08-01

    Satellite-derived evapotranspiration anomalies and normalized difference vegetation index (NDVI) products from Moderate Resolution Imaging Spectroradiometer (MODIS) data are currently used for African agricultural drought monitoring and food security status assessment. In this study, a process to evaluate satellite-derived evapotranspiration (ETa) products with a geospatial statistical exploratory technique that uses NDVI, satellite-derived rainfall estimate (RFE), and crop yield data has been developed. The main goal of this study was to evaluate the ETa using the NDVI and RFE, and identify a relationship between the ETa and Ethiopia's cereal crop (i.e., teff, sorghum, corn/maize, barley, and wheat) yields during the main rainy season. Since crop production is one of the main factors affecting food security, the evaluation of remote sensing-based seasonal ETa was done to identify the appropriateness of this tool as a proxy for monitoring vegetation condition in drought vulnerable and food insecure areas to support decision makers. The results of this study showed that the comparison between seasonal ETa and RFE produced strong correlation (R2 > 0.99) for all 41 crop growing zones in Ethiopia. The results of the spatial regression analyses of seasonal ETa and NDVI using Ordinary Least Squares and Geographically Weighted Regression showed relatively weak yearly spatial relationships (R2 < 0.7) for all cropping zones. However, for each individual crop zones, the correlation between NDVI and ETa ranged between 0.3 and 0.84 for about 44% of the cropping zones. Similarly, for each individual crop zones, the correlation (R2) between the seasonal ETa anomaly and de-trended cereal crop yield was between 0.4 and 0.82 for 76% (31 out of 41) of the crop growing zones. The preliminary results indicated that the ETa products have a good predictive potential for these 31 identified zones in Ethiopia. Decision makers may potentially use ETa products for monitoring cereal crop

  19. Comparison of the effects of symmetric and asymmetric temperature elevation and CO2 enrichment on yield and evapotranspiration of winter wheat (Triticum aestivum L.)

    PubMed Central

    Qiao, Yunzhou; Liu, Huiling; Kellomäki, Seppo; Peltola, Heli; Liu, Yueyan; Dong, Baodi; Shi, Changhai; Zhang, Huizhen; Zhang, Chao; Gong, Jinnan; Si, Fuyan; Li, Dongxiao; Zheng, Xin; Liu, Mengyu

    2014-01-01

    Under the changing climate, asymmetric warming pattern would be more likely during day and night time, instead of symmetric one. Concurrently, the growth responses and water use of plants may be different compared with those estimated based on symmetric warming. In this work, it was compared with the effects of symmetric (ETs) and asymmetric (ETa) elevation of temperature alone, and in interaction with elevated carbon dioxide concentration (EC), on the grain yield (GY) and evapotranspiration in winter wheat (Triticum aestivum L.) based on pot experiment in the North China Plain (NCP). The experiment was carried out in six enclosed-top chambers with following climate treatments: (1) ambient temperature and ambient CO2 (CON), (2) ambient temperature and elevated CO2 (EC), (3) elevated temperature and ambient CO2 (ETs; ETa), and (4) elevated temperature and elevated CO2 (ECETs, ECETa). In symmetric warming, temperature was increased by 3°C and in asymmetric one by 3.5°C during night and 2.5°C during daytime, respectively. As a result, GY was in ETa and ETs 15.6 (P < 0.05) and 10.3% (P < 0.05) lower than that in CON. In ECETs and ECETa treatments, GY was 14.9 (P < 0.05) and 9.1% (P < 0.05) higher than that in CON. Opposite to GY, evapotranspiration was 7.8 (P < 0.05) and 17.9% (P < 0.05) higher in ETa and ETs treatments and 7.2 (P < 0.05) and 2.1% (P > 0.05) lower in ECETs and ECETa treatments compared with CON. Thus, GY of wheat could be expected to increase under the changing climate with concurrent elevation of CO2 and temperature as a result of increased WUE under the elevated CO2. However, the gain would be lower under ETa than that estimated based on ETs due to higher evapotranspiration. PMID:24963392

  20. The electroproduction of etas and kaons

    SciTech Connect

    O.K. Baker

    2001-12-01

    Experimental results for the electromagnetic production of eta and K mesons are compared with QCD-inspired models. The eta mesons from the decay of S_11 resonance were used to study the momentum transfer dependence of the relevant helicity amplitude and cross section in the reaction ^1H(e,e'p)eta. The ^1H(e,e'K+)Lambda reaction was studied as a function of squared four-momentum transfer, Q^2, and of the virtual photon polarization parameter, epsilon. Both of these experiments were performed at Jefferson Lab during the early years of operation. The new precision data serve to constrain model calculations and provide new insights into the physical processes.

  1. Horizon crossing and inflation with large {eta}

    SciTech Connect

    Kinney, William H.

    2005-07-15

    I examine the standard formalism of calculating curvature perturbations in inflation at horizon crossing, and derive a general relation which must be satisfied for the horizon-crossing formalism to be valid. This relation is satisfied for the usual cases of power-law and slow-roll inflation. I then consider a model for which the relation is strongly violated, and the curvature perturbation evolves rapidly on superhorizon scales. This model has Hubble slow-roll parameter {eta}=3, but predicts a scale-invariant spectrum of density perturbations. I consider the case of hybrid inflation with large {eta}, and show that such solutions do not solve the '{eta} problem' in supergravity. These solutions correspond to field evolution which has not yet relaxed to the inflationary attractor solution, and may make possible new, more natural models on the string landscape.

  2. Model Error Estimation for the CPTEC Eta Model

    NASA Technical Reports Server (NTRS)

    Tippett, Michael K.; daSilva, Arlindo

    1999-01-01

    Statistical data assimilation systems require the specification of forecast and observation error statistics. Forecast error is due to model imperfections and differences between the initial condition and the actual state of the atmosphere. Practical four-dimensional variational (4D-Var) methods try to fit the forecast state to the observations and assume that the model error is negligible. Here with a number of simplifying assumption, a framework is developed for isolating the model error given the forecast error at two lead-times. Two definitions are proposed for the Talagrand ratio tau, the fraction of the forecast error due to model error rather than initial condition error. Data from the CPTEC Eta Model running operationally over South America are used to calculate forecast error statistics and lower bounds for tau.

  3. Study of high momentum eta' production in B --> eta'Xs.

    PubMed

    Aubert, B; Barate, R; Boutigny, D; Couderc, F; Gaillard, J-M; Hicheur, A; Karyotakis, Y; Lees, J P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; LeClerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Morgan, S E; Watson, A T; Watson, N K; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmuecker, H; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Mackay, C; Wilson, F F; Abe, K; Cuhadar-Donszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; McKemey, A K; Teodorescu, L; Blinov, V E; Bukin, A D; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Gary, J W; Layter, J; Shen, B C; Wang, K; del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, Sh; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Beringer, J; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Spradlin, P; Walkowiak, W; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Erwin, R J; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Roy, J; Smith, J G; van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Soffer, A; Toki, W H; Wilson, R J; Zhang, J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Schubert, J; Schubert, K R; Schwierz, R; Spaan, B; Bernard, D; Bonneaud, G R; Brochard, F; Grenier, P; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Bard, D J; Khan, A; Lavin, D; Muheim, F; Playfer, S; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Patteri, P; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Taylor, G P; Grenier, G J; Lee, S-J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Brigljević, V; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, E; Gamet, R; Kay, M; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Harrison, P F; Mohanty, G B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; George, S; Green, M G; Kurup, A; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Lafferty, G D; Lyon, A J; Williams, J C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Cote-Ahern, D; Taras, P; Nicholson, H; Cartaro, C; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; Wilden, L; Jessop, C P; LoSecco, J M; Gabriel, T A; Allmendinger, T; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Ter-Antonyan, R; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; de la Vaissière, Ch; Del Buono, L; Hamon, O; John, M J J; Leruste, Ph; Ocariz, J; Pivk, M; Roos, L; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Anulli, F; Biasini, M; Peruzzi, I M; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Del Gamba, V; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martinez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lu, C; Miftakov, V; Olsen, J; Smith, A J S; Varnes, E W; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Safai Tehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Geddes, N I; Gopal, G P; Olaiya, E O; Xella, S M; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P-F; Hamel de Monchenault, G; Kozanecki, W; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yeche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Convery, M R; Cristinziani, M; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Elsen, E E; Field, R C; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Va'vra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wright, D H; Young, C C; Burchat, P R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihalyi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; von Wimmersperg-Toeller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H

    2004-08-01

    We measure the branching fraction for the charmless semi-inclusive process B --> eta'Xs, where the eta' meson has a momentum in the range 2.0 to 2.7 GeV/c in the upsilon4S center-of-mass frame and Xs represents a system comprising a kaon and zero to four pions. We find B(B --> eta'Xs) = [3.9 +/- 0.8(stat) +/- 0.5(syst) +/- 0.8(model)] x 10(-4). We also obtain the Xs mass spectrum and find that it fits models predicting high masses. PMID:15323619

  4. An upgraded version of the Eta model

    NASA Astrophysics Data System (ADS)

    Mesinger, Fedor; Chou, Sin Chan; Gomes, Jorge L.; Jovic, Dusan; Bastos, Paulo; Bustamante, Josiane F.; Lazic, Lazar; Lyra, André A.; Morelli, Sandra; Ristic, Ivan; Veljovic, Katarina

    2012-05-01

    Upgrades implemented over a number of years in an open source version of the Eta model, posted at the CPTEC web site http://etamodel.cptec.inpe.br/ , are summarized and examples of benefits are shown. The version originates from the NCEP's Workstation Eta code posted on the NCEP web site http://www.emc.ncep.noaa.gov/mmb/wrkstn_eta eta" TargetType="URL"/> , which differs from the NCEP's latest operational Eta by having the WRF-NMM nonhydrostatic option included. Most of the upgrades made resulted from attention paid to less than satisfactory performance noted in several Eta results, and identification of the reasons for the problem. Others came from simple expectation that including a feature that is physically justified but is missing in the code should help. The most notable of the upgrades are the introduction of the so-called sloping steps, or discretized shaved cells topography; piecewise-linear finite-volume vertical advection of dynamic variables; vapor and hydrometeor loading in the hydrostatic equation, and changes aimed at refining the convection schemes available in the Eta. Several other modifications have to do with the calculation of exchange coefficients, conservation in the vertical diffusion, and diagnostic calculation of 10-m winds. Several examples showing improved performance resulting from the dynamics changes are given. One includes a case of unrealistically low temperatures in several mountain basins generated by a centered vertical advection difference scheme's unphysical advection from below ground, removed by its replacement with a finite-volume scheme. Another is that of increased katabatic winds in the Terra Nova Bay Antarctica region. Successful forecast of the severe downslope zonda wind case in the lee of

  5. 31 CFR 208.5 - Availability of the ETA SM.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance: Treasury 2 2014-07-01 2014-07-01 false Availability of the ETA SM. 208.5... DISBURSEMENTS § 208.5 Availability of the ETA SM. An individual who receives a Federal benefit, wage, salary, or retirement payment shall be eligible to open an ETA SM at any Federally-insured financial institution...

  6. 31 CFR 208.5 - Availability of the ETA SM.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 2 2013-07-01 2013-07-01 false Availability of the ETA SM. 208.5... DISBURSEMENTS § 208.5 Availability of the ETA SM. An individual who receives a Federal benefit, wage, salary, or retirement payment shall be eligible to open an ETA SM at any Federally-insured financial institution...

  7. 31 CFR 208.5 - Availability of the ETA SM.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Availability of the ETA SM. 208.5... DISBURSEMENTS § 208.5 Availability of the ETA SM. An individual who receives a Federal benefit, wage, salary, or retirement payment shall be eligible to open an ETA SM at any Federally-insured financial institution...

  8. 31 CFR 208.5 - Availability of the ETA SM.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 2 2011-07-01 2011-07-01 false Availability of the ETA SM. 208.5... DISBURSEMENTS § 208.5 Availability of the ETA SM. An individual who receives a Federal benefit, wage, salary, or retirement payment shall be eligible to open an ETA SM at any Federally-insured financial institution...

  9. 31 CFR 208.5 - Availability of the ETA SM.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 2 2012-07-01 2012-07-01 false Availability of the ETA SM. 208.5... DISBURSEMENTS § 208.5 Availability of the ETA SM. An individual who receives a Federal benefit, wage, salary, or retirement payment shall be eligible to open an ETA SM at any Federally-insured financial institution...

  10. Observation of B^+\\to\\eta\\rho^+ and Search for B^0 Decays to\\eta^\\prime\\eta, \\eta\\pi^0, \\eta^\\prime\\pi^0, and \\omega\\pi^0

    SciTech Connect

    Aubert, Bernard; Bona, Marcella; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Lopez, L.; Palano, Antimo; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Abrams, G.S.; Battaglia, Marco; Brown, D.N.; Button-Shafer, Janice; Cahn, Robert N.; /LBL, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Harvard U. /Heidelberg U. /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Karlsruhe U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Paris U., VI-VII /Pennsylvania U. /INFN, Perugia /INFN, Pisa /Princeton U. /INFN, Rome /Rostock U. /Rutherford /DSM, DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Albany /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /INFN, Trieste /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison

    2008-04-22

    The authors present measurements of branching fractions for five B-meson decays to two-body charmless final states. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 459 million B{bar B} pairs. The results for branching fractions are, in units of 10{sup -6} (upper limits at 90% C.L.): {Beta}(B{sup +} {yields} {eta}{rho}{sup +}) = 9.9 {+-} 1.2 {+-} 0.8, {Beta}(B{sup 0} {yields} {eta}{prime}{eta}) = 0.5 {+-} 0.4 {+-} 0.1 (< 1.2), {Beta}(B{sup 0} {yields} {eta}{pi}{sup 0}) = 0.9 {+-} 0.4 {+-} 0.1 (< 1.5), {Beta}(B{sup 0} {yields} {eta}{prime}{pi}{sup 0}) = 0.9 {+-} 0.4 {+-} 0.1 (< 1.5), and {Beta}(B{sup 0}{sup 0} {yields} {omega}{pi}{sup 0}) = {eta}{rho}{sup +} mode, they measure the charge asymmetry {Alpha}{sub ch} (B{sup +} {yields} {eta}{rho}{sup +}) = 0.13 {+-} 0.11 {+-} 0.02.

  11. Exploring the use of multi-sensor data fusion for daily evapotranspiration mapping at field scale

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern practices of water management in agriculture can significantly benefit from accurate mapping of crop water consumption at field scale. Assuming that actual evapotranspiration (ET) is the main water loss in land hydrological balance, remote sensing data represent an invaluable tool for water u...

  12. A comparison of operational remote sensing-based models for estimating crop evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The integration of remotely sensed data into models of actual evapotranspiration has allowed for the estimation of water consumption across agricultural regions. Two modeling approaches have been successfully applied. The first approach computes a surface energy balance using the radiometric surface...

  13. Influence of potential evapotranspiration on the water balance of sugarcane fields in Maui, Hawaii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The year-long warm temperatures and other climatic characteristics of the Pacific Ocean Islands have made Hawaii an optimum place for growing sugarcane; however, irrigation is essential to satisfy the large water demand of sugarcane. Under the Hawaiian tropical weather, actual evapotranspiration (A...

  14. Evaluation of Pan Coefficients for Estimating Reference Evapotranspiration in Southern Taiwan

    NASA Astrophysics Data System (ADS)

    Yeh, H.

    2006-12-01

    Evapotranspiration is an important process of water transfer in the hydrosphere and atmosphere, which plays an active role in the hydrological cycle. Evaporation pan (Epan) data are often used to estimate reference evapotranspiration (ETref) for use in water resource planning. Generally, ETref is estimated as the product of the Epan data and a pan coefficient (Kpan). However, reliable estimation of ETref using Epan depends on the accurate determination of pan coefficients Kpan. Many different methods for estimating ETref have been developed, among which the Penman-Monteith method is demonstrated to be especially excellent by the Food and Agriculture Organization (FAO). In this study, the Penman-Monteith reference evapotranspiration, pan evaporation, and pan coefficient are calculated, compared and regionally mapped at nine meteorological stations during 1990-2004 in Southern Taiwan. The results show the reference evapotranspiration and pan evaporation have similar regional distribution patterns in the southern Taiwan both with the highest values being in the lower region and the lowest values being in the upper region. In addition, the pan coefficient, Kpan, varies both regionally and seasonally. Smallest Kpan values are found in the upper reach of the southern Taiwan, meaning that the relative difference between the reference evapotranspiration and pan evaporation is the biggest in the region, the largest Kpan values are obtained in the western area of southern Taiwan. This distribution pattern provides valuable information for regional hydrological studies since it is one of the most important factors determining regional actual evapotranspiration.

  15. NOAA AVHRR and its uses for rainfall and evapotranspiration monitoring

    NASA Technical Reports Server (NTRS)

    Kerr, Yann H.; Imbernon, J.; Dedieu, G.; Hautecoeur, O.; Lagouarde, J. P.

    1989-01-01

    NOAA-7 Advanced Very High Resolution Radiometer (AVHRR) Global Vegetation Indices (GVI) were used during the 1986 rainy season (June-September) over Senegal to monitor rainfall. The satellite data were used in conjunction with ground-based measurements so as to derive empirical relationships between rainfall and GVI. The regression obtained was then used to map the total rainfall corresponding to the growing season, yielding good results. Normalized Difference Vegetation Indices (NDVI) derived from High Resolution Picture Transmission (HRPT) data were also compared with actual evapotranspiration (ET) data and proved to be closely correlated with it with a time lapse of 20 days.

  16. Study of B Meson Decays with Excited eta and eta-prime Mesons

    SciTech Connect

    Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prudent, X.; Tisserand, V.; Zghiche, A.; Garra Tico, J.; Grauges, E.; Lopez, L.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Abrams, G.S.; Battaglia, M.; Brown, D.N.; Button-Shafer, J.; /Energy Sci. Network /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /Frascati /Genoa U. /Harvard U. /Heidelberg U. /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Karlsruhe U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /Padua U. /Paris U., VI-VII /Pennsylvania U. /Perugia U. /Pisa U. /Prairie View A-M /Princeton U. /INFN, Rome /Rostock U. /Rutherford /DSM, DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Albany /Tennessee U. /Texas U. /Texas U., Dallas /Turin U. /INFN, Turin /Trieste U. /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison /Yale U.

    2008-04-18

    Using 383 million B{bar B} pairs from the BABAR data sample, they report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to K{bar K}* or {eta}{pi}{pi} final states with mass in the range (1.2-1.8) GeV/c{sup 2}. They observe a significant enhancement at the low K{bar K}* invariant mass which is interpreted as B{sup +} {yields} {eta}(1475)K{sup +}, find evidence for the decay B{sup +} {yields} {eta}(1295)K{sup +}, and place upper limits on the decays B{sup +} {yields} {eta}(1405)K{sup +}, B{sup +} {yields} f{sub 1}(1285)K{sup +}, B{sup +} {yields} f{sub 1}(1420)K{sup +}, and B{sup +} {yields} {phi}(1680)K{sup +}.

  17. THE ENVIRONMENTAL TECHNOLOGIES ACCEPTANCE (ETA) PROGRAM

    SciTech Connect

    Christina B. Behr-Andres

    2001-10-01

    The objective of the Environmental Technologies Acceptance (ETA) Program at the Energy & Environmental Research Center (EERC) is to advance the development, commercial acceptance, and timely deployment of selected private sector technologies for the cleanup of sites in the nuclear defense complex as well as the greater market. As a result of contract changes approved by National Energy Technology Laboratory (NETL) representatives to incorporate activities previously conducted under another NETL agreement, there are now an additional task and an expansion of activities within the stated scope of work of the ETA program. As shown in Table 1, this cooperative agreement, funded by NETL (No. DE-FC26-00NT40840), consists of four tasks: Technology Selection, Technology Development, Technology Verification, and System Engineering. As currently conceived, ETA will address the needs of as many technologies as appropriate under its current 3-year term. There are currently four technical subtasks: Long-Term Stewardship Initiative at the Mound Plant Site; Photocatalysis of Mercury-Contaminated Water; Subcritical Water Treatment of PCB and Metal-Contaminated Paint Waste; and Vegetative Covers for Low-Level Waste Repositories. This report covers activities during the second six months of the three-year ETA program.

  18. Superluminous supernovae: no threat from eta Carinae.

    PubMed

    Thomas, Brian C; Melott, Adrian L; Fields, Brian D; Anthony-Twarog, Barbara J

    2008-02-01

    Recently, Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of approximately 10(44) Joules. It was proposed that the progenitor may have been a massive evolved star similar to eta Carinae, which resides in our own Galaxy at a distance of about 2.3 kpc. eta Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given that its rotation axis is unlikely to produce a gamma-ray burst oriented toward Earth, eta Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We have found that, given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over approximately 10(4) y and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovae-e-ndocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered "dangerous" for other reasons. However, due to reddening and extinction by the interstellar medium, eta Carinae is unlikely to trigger such effects to any significant degree. PMID:18199005

  19. A SEA CHANGE IN ETA CARINAE

    SciTech Connect

    Mehner, Andrea; Davidson, Kris; Humphreys, Roberta M.; Martin, John C.; Ishibashi, Kazunori; Ferland, Gary J.; Walborn, Nolan R.

    2010-07-01

    Major stellar-wind emission features in the spectrum of {eta} Car have recently decreased by factors of order 2 relative to the continuum. This is unprecedented in the modern observational record. The simplest, but unproven, explanation is a rapid decrease in the wind density.

  20. Assessing Macroscopic Evapotranspiration Function Response to Climate

    NASA Astrophysics Data System (ADS)

    Gharun, M.; Vervoort, R. W.; Turnbull, T.; Henry, J.; Adams, M.

    2012-12-01

    Evapotranspiration (ET) by forests can reach up to 100% of rainfall in Australia, and is a substantial component of the water balance. Transpiration is a major part of the ET and it is well-known that transpiration depends on a combination of physiological and environmental controls. As a consequence of well-ventilated canopies of eucalypt forests and close decoupling to the atmosphere, atmospheric conditions exert a large control over transpiration. We measured a suit of environmental variables including temperature, humidity, radiation, and soil moisture concurrently with transpiration in a range of eucalypt forests. We observed that atmospheric demand (VPD) exerts the strongest control over transpiration. Experimental evidence also showed a strong dependency of the control on soil moisture abundance in the top soil layer. In many eco-hydrological models actual ET is represented with a linear transformation of potential ET based on the soil moisture condition, a so-called macroscopic approach. Such ET functions lump various soil and plant factors, are not experimentally supported and therefore quite poorly validated. Different combinations of atmospheric demand and soil moisture availability lead to diverse behaviour of the macroscopic ET function. Based on our observations in this study, we propose a novel approach that improves portray of transpiration, evaporation, drainage and hence the loss of water from the root zone. We used a modified version of the Norwegian HBV model to test our approach over a medium size catchment (150 km2) in south east Australia.

  1. Interaction of eta mesons with nuclei

    NASA Astrophysics Data System (ADS)

    Kelkar, N. G.; Khemchandani, K. P.; Upadhyay, N. J.; Jain, B. K.

    2013-06-01

    Back in the mid-1980s, a new branch of investigation related to the interaction of eta mesons with nuclei came into existence. It started with the theoretical prediction of possible exotic states of eta mesons and nuclei bound by the strong interaction and later developed into an extensive experimental program to search for such unstable states as well as understand the underlying interaction via eta-meson producing reactions. The vast literature of experimental as well as theoretical works that studied various aspects of eta-producing reactions such as the π+n → ηp, pd → 3Heη, p 6Li → 7Be η and γ 3He → η X, to name a few, had but one objective in mind: to understand the eta-nucleon (ηN) and hence the η-nucleus interaction which could explain the production data and confirm the existence of some η-mesic nuclei. In spite of these efforts, there remain uncertainties in the knowledge of the ηN and hence the η-nucleus interaction. Therefore, this review is an attempt to bind together the findings in these works and draw some global and specific conclusions which can be useful for future explorations. The ηN scattering length (which represents the strength of the η-nucleon interaction) using different theoretical models and analyzing the data on η production in pion, photon and proton induced reactions was found to be spread out in a wide range, namely, 0.18 ⩽ ℜe aηN ⩽ 1.03 fm and 0.16 ⩽ ℑm aηN ⩽ 0.49 fm. Theoretical searches of heavy η-mesic nuclei based on η-nucleus optical potentials and lighter ones based on Faddeev type few-body approaches predict the existence of several quasibound and resonant states. Although some hints of η-mesic states such as ^3_{\\eta} He and ^{25}_{\\eta} Mg do exist from previous experiments, the promise of clearer signals for the existence of η-mesic nuclei lies in the experiments to be performed at the J-PARC, MAMI and COSY facilities in the near future. This review is aimed at giving an overall

  2. Calorimetric studies of the heats of protonation of the dangling phosphorus in [eta][sup 1]-Ph[sub 2]PCH[sub 2]PPh[sub 2] complexes of chromium, molybdenum, and tungsten

    SciTech Connect

    Rottink, M.K.; Angelici, R.J. )

    1993-05-26

    Titration calorimetry has been used to determine the heats of protonation ([Delta]H[sub HP]) of M(CO)[sub 5]([eta][sup 1]-dppm) (M = Cr, Mo, W) and fac-M(CO)[sub 3](N-N)([eta][sup 1]-dppm) (M = Mo, N-N = bipy, phen; M = w, N-N = bipy) complexes with CF[sub 3]SO[sub 3]H in 1,2-dichloroethane solvent at 25.0 [degrees]C. Spectroscopic studies show that protonation occurs at the uncoordinated phosphorus atom of the [eta][sup 1]-coordinated dppm (Ph[sub 2]PCH[sub 2]PPh[sub 2]) ligand. For dppm, its monoprotonated form (dppmH[sup +]), and these complexes, the basicity ([Delta]H[sub HP]) of the dangling phosphorus increases from -14.9 kcal/mol to -23.1 kcal/mol in the order: dppmH[sup +] eta][sup 1]-dppm) < Mo(CO)[sub 5]([eta][sup 1]-dppm) < W(CO)[sub 5]([eta][sup 1]-dppm) < dppm[le]fac-Mo(CO)[sub 3]([eta][sup 2]-bipy)([eta][sup 1]-dppm) < fac-Mo(CO)[sub 3]([eta][sup 2]-phen)([eta][sup 1]-dppm) [approx] fac-W(CO)[sub 3]([eta][sup 2]-bipy)([eta][sup 1]-dppm). In this series, H[sup +] is more electron-withdrawing than M(CO)[sub 5] (M = Cr, Mo, W); Mo(CO)[sub 3]([eta][sup 2]-phen) and W(CO)[sub 3]-([eta][sup 2]-bipy) actually enhance the basicity of the dangling phosphorus as compared with dppm itself. The basicity ([Delta]H[sub HM]) of fac-W(CO)[sub 3]([eta][sup 2]-bipy)(PPh[sub 2]Me), which protonates at the metal center to give a seven-coordinate complex, is -18.8 kcal/mol. Thus, the basicity of the dangling phosphorus atom in fac-W(CO)[sub 3]([eta][sup 2]-bipy)([eta][sup 1]-dppm) is approximately 4.3 kcal/mol more basic than the metal center.

  3. Some Comments on the Decays of eta (550)

    DOE R&D Accomplishments Database

    Veltman, M.; Yellin, J.

    1966-07-01

    Various decay modes of the {eta}(500) are discussed. The relations, through SU{sub 3} and the Gell-Mann, Sharp, Wagner model, between the {eta}-decay modes and the modes {eta} {yields} {pi}{pi}{gamma), {pi}{sup 0} {yields} {gamma}{gamma} are investigated taking into account {eta}-{eta}{sup *} mixing. The present experimental values for the neutral branching ratios plus the shape of the {eta} {yields} {pi}{sup +}{pi}{sup {minus}}{pi}{sup 0} Dalitz plot are shown to require a 25% {vert_bar}{Delta}{rvec I}{vert_bar} = 3 contribution to the {eta} {yields} 3{pi} amplitude. The connection between a possible charge asymmetry in {eta} {yields} {pi}{sup +}{pi}{sup {minus}}{pi}{sup 0} and the branching ratio {Gamma}{sub {eta} {yields} {pi}{sup 0}e{sup +}e{sup {minus}}}/{Gamma}{sub {eta}}{sup all} is investigated in the framework of a model proposed earlier by several authors. It is shown that there is no conflict between the existing data and this model. The Dalitz plot distribution of {eta} {yields} {pi}{sup +}{pi}{sup {minus}}{pi}{sup 0} is discussed under various assumptions about the properties of the interaction responsible for the decay. (auth)

  4. The Texas High Plains Evapotranspiration (TXHPET) network

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The newly developed Texas High Plains Evapotranspiration (TXHPET) network is comprised of the North Plains and South Plains evapotranspiration (ET) networks. The TXHPET network currently entails the operation of 18 meteorological stations located in 15 Texas counties and regional coverage is estima...

  5. THE ASCE STANDARDIZED REFERENCE EVAPOTRANSPIRATION EQUATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This report describes the standardization of calculation of reference evapotranspiration (ET) as recommended by the Task Committee on Standardization of Reference Evapotranspiration of the Environmental and Water Resources Institute of the American Society of Civil Engineers. The purpose of the stan...

  6. Differential cross sections for the reactions gamma p-> p eta and gamma p -> p eta-prime

    SciTech Connect

    M. Williams, Z. Krahn, D. Applegate, M. Bellis, C.A. Meyer, for the CLAS Collaboration

    2009-10-01

    High-statistics differential cross sections for the reactions gamma p -> p eta and gamma p -> p eta-prime have been measured using the CLAS at Jefferson Lab for center-of-mass energies from near threshold up to 2.84 GeV. The eta-prime results are the most precise to date and provide the largest energy and angular coverage. The eta measurements extend the energy range of the world's large-angle results by approximately 300 MeV. These new data, in particular the eta-prime measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.

  7. Glue content and mixing angle of the {eta}-{eta}{sup '} system: The effect of the isoscalar 0{sup -} continuum

    SciTech Connect

    Nasrallah, N.F.

    2004-12-01

    Masses and topological charges of the {eta} and {eta}{sup '} mesons are expressed in terms of the singlet-octet mixing angle {theta}. Contributions of the pseudoscalar 0{sup -} continuum are evaluated in a model independent way. Applications to the decay {eta}{yields}3{pi} and to the radiative decay of vector mesons involving {eta} and {eta}{sup '} are considered. Agreement with experiment is, in general, good and the results quite stable for -30.5 deg. < or approx. {theta} < or approx. -18.5 deg.

  8. etas_solve: A robust program to estimate the ETAS parameters

    NASA Astrophysics Data System (ADS)

    Yagi, Y.; Kasahara, A.

    2015-12-01

    The epidemic-type aftershock sequence (ETAS) model introduced by Ogata (1988) has been widely used to quantitatively describe seismicity (e.g. Ogata, 1992; Llenos et al., 2009). However, only a few programs for estimation of the ETAS parameters are publicly available, and it is difficult to automatically apply some of them to observed data due to initial value dependence (e.g. Ogata, 2006). A robust ETAS estimation program is required to meet the recent enhancement of earthquake catalogs. In this study, we developed a new program, etas_solve, that is based on Newton's method and calculates exact gradient and Hessian by using the automatic differentiation technique (Griewank, 1989). The program also supports auxiliary window in time and magnitude (Wang et al., 2010).To demonstrate robustness of the developed program, we tested the dependence of estimated parameters on the choice of initial value by running the program from 1,024 randomly chosen initial values, and then compared the results with that of SAPP (Ogata 2006). We used aftershock data of 26th July 2003 earthquake of M6.2 at the northern Miyagi japan, which is shipped with SAPP, as a testing data. We found that estimation values with etas_solve were independent of the initial value for the testing data, while that with SAPP were varied with the initial value. Although there was initial value dependence in the SAPP's results, the estimated values by SAPP with small (≤10-5) gradient coincided with the solution by etas_solve. etas_solve took longer computation time per iteration than SAPP due to the exact Hessian calculation, but total execution time was comparable to that of SAPP since less number of iterations for convergence was required. In addition, etas_solve was faster than SAPP on multicore machines (around 8-fold speed up with a 16 core machine) since etas_solve is parallelized by OpenMP.etas_solve is written in Fortran and distributed under GNU General Public License at https

  9. Recharge and Evapotranspiration Assessment In Kalahari

    NASA Astrophysics Data System (ADS)

    Lubczynski, M.; Obakeng, O.

    2006-12-01

    Sustainability of groundwater resources in Kalahri is constrained not only by recharge to the aquifers but also by discharge from them. Natural groundwater discharge takes place in 3 different ways, as aquifer groundwater outflow, direct tree root water uptake called groundwater transpiration (Tg) and as upward vapor-liquid water movement called groundwater evaporation (Eg), the latter two called groundwater evapotranspiration (ETg). The evaluation of ETg and recharge was the main goal of this study. Due to generally large depth of groundwater table in Kalahari, >60 m, Eg was assumed as negligible component of groundwater balances while in contrast Tg has been considered significant already since 90-ties. This was because of fragments of tree roots of Boscia albitrunca and Acacia erioloba found in borehole cores at depth of >60 m. Some of those roots reach groundwater, which allow them to remain green throughout dry seasons. This study was carried out using hydrological monitoring consisting of 10 multi-sensor towers and 17 groundwater monitoring points. Soil moisture movement was investigated by profile monitoring. The deepest profile was down to 76 m depth. The soil moisture results revealed complicated pattern characterized by a combination of diffuse and preferential flow. The actual evapotranspiration was estimated by the Bowen-ratio and temperature-profile methods which provided overestimated results as compared with rainfall so the recharge could not be deduced directly. Therefore recharge was derived indirectly, through 1D lumped parameter model that used rainfall and PET as input and heads as calibration reference. That model indicated recharge 0-50 mm/yr. For understanding tree impact upon groundwater recharge, tree sap velocity was monitored for 2 years using the Granier method on 41 trees of 9 species in 8 plots of 30x30m. The estimated plot transpirations showed large spatio-temporal variability, 3-71 mm/yr and occasionally exceeded recharge. In order

  10. Physics and Outlook for Rare, All-neutral Eta Decays

    SciTech Connect

    Mack, David J.

    2014-06-01

    The $\\eta$ meson provides a laboratory to study isospin violation and search for new flavor-conserving sources of C and CP violation with a sensitivity approaching $10^{-6}$ of the isospin-conserving strong amplitude. Some of the most interesting rare $\\eta$ decays are the neutral modes, yet the effective loss of photons from the relatively common decay $\\eta \\rightarrow 3\\pi^0 \\rightarrow 6\\gamma$ (33$\\%$) has largely limited the sensitivity for decays producing 3-5$\\gamma$'s. Particularly important relevant branches include the highly suppressed $\\eta \\rightarrow \\pi^0 2\\gamma \\rightarrow 4\\gamma$, which provides a rare window on testing models of $O(p^6)$ contributions in ChPTh, and $\\eta \\rightarrow 3\\gamma$ and $\\eta \\rightarrow 2\\pi^0 \\gamma \\rightarrow 5\\gamma$ which provide direct constraints on C violation in flavor-conserving processes. The substitution of lead tungstate in the forward calorimeter of the GluEx setup in Jefferson Lab's new Hall D would allow dramatically improved measurements. The main niche of this facility, which we call the JLab Eta Factory (JEF), would be $\\eta$ decay neutral modes. However, this could likely be expanded to rare $\\eta'(958)$ decays for low energy QCD studies as well as $\\eta$ decays involving muons for new physics searches.

  11. Eta-mesic nuclei: Past, present, future

    SciTech Connect

    Haider, Q.; Liu, Lon -Chang

    2015-09-23

    Eta-mesic nucleus or the quasibound nuclear state of an eta (η) meson in a nucleus is caused by strong interaction force alone. This new type of nuclear species, which extends the landscape of nuclear physics, has been extensively studied since its prediction in 1986. We review and analyze in great detail the models of the fundamental η–nucleon interaction leading to the formation of an η–mesic nucleus, the methods used in calculating the properties of a bound η, and the approaches employed in the interpretation of the pertinent experimental data. In view of the successful observation of the η–mesic nucleus 25Mgη and other promising experimental results, future direction in searching for more η–mesic nuclei is suggested.

  12. Eta-mesic nuclei: Past, present, future

    DOE PAGESBeta

    Haider, Q.; Liu, Lon -Chang

    2015-09-23

    Eta-mesic nucleus or the quasibound nuclear state of an eta (η) meson in a nucleus is caused by strong interaction force alone. This new type of nuclear species, which extends the landscape of nuclear physics, has been extensively studied since its prediction in 1986. We review and analyze in great detail the models of the fundamental η–nucleon interaction leading to the formation of an η–mesic nucleus, the methods used in calculating the properties of a bound η, and the approaches employed in the interpretation of the pertinent experimental data. In view of the successful observation of the η–mesic nucleus 25Mgηmore » and other promising experimental results, future direction in searching for more η–mesic nuclei is suggested.« less

  13. HUBBLE SHOWS EXPANSION OF ETA CARINAE DEBRIS

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The furious expansion of a huge, billowing pair of gas and dust clouds are captured in this NASA Hubble Space Telescope comparison image of the supermassive star Eta Carinae. To create the picture, astronomers aligned and subtracted two images of Eta Carinae taken 17 months apart (April 1994, September 1995). Black represents where the material was located in the older image, and white represents the more recent location. (The light and dark streaks that make an 'X' pattern are instrumental artifacts caused by the extreme brightness of the central star. The bright white region at the center of the image results from the star and its immediate surroundings being 'saturated' in one of the images.)Photo Credit: Jon Morse (University of Colorado), Kris Davidson (University of Minnesota), and NASA Image files in GIF and JPEG format and captions may be accessed on Internet via anonymous ftp from oposite.stsci.edu in /pubinfo.

  14. Eta Carinae and Other Luminous Blue Variables

    NASA Technical Reports Server (NTRS)

    Corcoran, M. F.

    2006-01-01

    Luminous Blue Variables (LBVs) are believed to be evolved, extremely massive stars close to the Eddington Limit and hence prone to bouts of large-scale, unstable mass loss. I discuss current understanding of the evolutionary state of these objects, the role duplicity may play and known physical characteristics of these stars using the X-ray luminous LBVs Eta Carinae and HD 5980 as test cases.

  15. The radio source around Eta Carinae

    NASA Technical Reports Server (NTRS)

    White, S. M.; Duncan, R. A.; Lim, J.; Nelson, G. J.; Drake, S. A.; Kundu, M. R.

    1994-01-01

    We present high spatial resolution radio observations of the peculiar southern star Eta Carinae, made with the Australian Telescope. The images, at 8 and 9 GHz with a resolution of 1.0 arcsec show a source of dimension 10 arcsec and total flux of 0.7 Jy dominated by a strong central peak. The radio emission is unpolarized and offers no support to models which invoke degenerate stars or more exotic objects within the core of Eta Car. In these data we find no evidence for more than one energy source in the core with arcsecond separations as some infrared observations have suggested. Several levels of structure are evident in the radio image, which shows symmetry on the larger scales. Conventional formulae for stellar wind radio sources give a mass loss rate of order 3 x 10(exp -4) Solar Mass/yr based on the radio flux in the central peak, which yields a wind momentum flux of order 20% of the momentum flux available from the star's radiation field. The radio emission at these frequencies is consistent with thermal emission from gas flowing away from a 'luminous blue variable' star (LBV) Eta Car is probably the brightest thermal stellar wind radio source in the sky.

  16. Study of B meson decays with excited eta and eta' mesons.

    PubMed

    Aubert, B; Bona, M; Boutigny, D; Karyotakis, Y; Lees, J P; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Tico, J Garra; Grauges, E; Lopez, L; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lopes Pegna, D; Lynch, G; Mir, L M; Orimoto, T J; Osipenkov, I L; Ronan, M T; Tackmann, K; Tanabe, T; Wenzel, W A; del Amo Sanchez, P; Hawkes, C M; Watson, A T; Held, T; Koch, H; Pelizaeus, M; Schroeder, T; Steinke, M; Walker, D; Asgeirsson, D J; Cuhadar-Donszelmann, T; Fulsom, B G; Hearty, C; Mattison, T S; McKenna, J A; Barrett, M; Khan, A; Saleem, M; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Martin, E C; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Liu, F; Long, O; Shen, B C; Zhang, L; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Schalk, T; Schumm, B A; Seiden, A; Wilson, M G; Winstrom, L O; Chen, E; Cheng, C H; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Andreassen, R; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Gabareen, A M; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Merkel, J; Petzold, A; Spaan, B; Wacker, K; Klose, V; Kobel, M J; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Lombardo, V; Thiebaux, Ch; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Watson, J E; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cecchi, A; Cibinetto, G; Franchini, P; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Santoro, V; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D J; Dauncey, P D; Flack, R L; Nash, J A; Panduro Vazquez, W; Tibbetts, M; Behera, P K; Chai, X; Charles, M J; Mallik, U; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gao, Y Y; Gritsan, A V; Guo, Z J; Lae, C K; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Béquilleux, J; D'Orazio, A; Davier, M; Grosdidier, G; Höcker, A; Lepeltier, V; Le Diberder, F; Lutz, A M; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Serrano, J; Sordini, V; Stocchi, A; Wang, W F; Wormser, G; Lange, D J; Wright, D M; Bingham, I; Burke, J P; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; George, K A; Di Lodovico, F; Menges, W; Sacco, R; Cowan, G; Flaecher, H U; Hopkins, D A; Paramesvaran, S; Salvatore, F; Wren, A C; Brown, D N; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; West, T J; Yi, J I; Anderson, J; Chen, C; Jawahery, A; Roberts, D A; Simi, G; Tuggle, J M; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Salvati, E; Saremi, S; Cowan, R; Dujmic, D; Fisher, P H; Koeneke, K; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Zhao, M; Zheng, Y; Mclachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; De Nardo, G; Fabozzi, F; Lista, L; Monorchio, D; Sciacca, C; Baak, M A; Raven, G; Snoek, H L; Jessop, C P; Knoepfel, K J; LoSecco, J M; Benelli, G; Corwin, L A; Honscheid, K; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Wong, Q K; Blount, N L; Brau, J; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gagliardi, N; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Ben-Haim, E; Briand, H; Calderini, G; Chauveau, J; David, P; Del Buono, L; de la Vaissière, Ch; Hamon, O; Leruste, Ph; Malclès, J; Ocariz, J; Perez, A; Prendki, J; Gladney, L; Biasini, M; Covarelli, R; Manoni, E; Angelini, C; Batignani, G; Bettarini, S; Carpinelli, M; Cenci, R; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Haire, M; Biesiada, J; Elmer, P; Lau, Y P; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Baracchini, E; Bellini, F; Cavoto, G; del Re, D; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Jackson, P D; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Renga, F; Voena, C; Ebert, M; Hartmann, T; Schröder, H; Waldi, R; Adye, T; Castelli, G; Franek, B; Olaiya, E O; Ricciardi, S; Roethel, W; Wilson, F F; Emery, S; Escalier, M; Gaidot, A; Ganzhur, S F; Hamel de Monchenault, G; Kozanecki, W; Vasseur, G; Yèche, Ch; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Claus, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Grenier, P; Hast, C; Hryn'ova, T; Innes, W R; Kaminski, J; Kelsey, M H; Kim, H; Kim, P; Kocian, M L; Leith, D W G S; Li, S; Luitz, S; Luth, V; Lynch, H L; MacFarlane, D B; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ofte, I; Perazzo, A; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Va'vra, J; van Bakel, N; Wagner, A P; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Ruland, A M; Schilling, C J; Schwitters, R F; Izen, J M; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Pelliccioni, M; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martinez-Vidal, F; Milanes, D A; Oyanguren, A; Albert, J; Banerjee, Sw; Bhuyan, B; Hamano, K; Kowalewski, R; Nugent, I M; Roney, J M; Sobie, R J; Harrison, P F; Ilic, J; Latham, T E; Mohanty, G B; Band, H R; Chen, X; Dasu, S; Flood, K T; Hollar, J J; Kutter, P E; Pan, Y; Pierini, M; Prepost, R; Wu, S L; Neal, H

    2008-08-29

    Using 383 x 10(6) BBover pairs from the BABAR data sample, we report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to KKover* or etapipi final states with mass in the range (1.2-1.8) GeV/c2. We observe a significant enhancement at the low KKover* invariant mass which is interpreted as B+-->eta(1475)K+, find evidence for the decay B+-->eta(1295)K+, and place upper limits on the decays B+-->eta(1405)K+, B+-->f1(1285)K+, B+-->f1(1420)K+, and B+-->phi(1680)K+. PMID:18851601

  17. Evapotranspiration from the Lower Walker River Basin, West-Central Nevada, Water Years 2005-07

    USGS Publications Warehouse

    Allander, Kip K.; Smith, J. LaRue; Johnson, Michael J.

    2009-01-01

    evapotranspiration station in a saltcedar grove, measurements indicated a possible decrease in evapotranspiration of about 50 percent due to defoliation of the saltcedar by the saltcedar leaf beetle. Total evapotranspiration from the evapotranspiration units identified in the Lower Walker River basin was about 231,000 acre-feet per year (acre-ft/yr). Of this amount, about 45,000 acre-ft/yr originated from direct precipitation, resulting in net evapotranspiration of about 186,000 acre-ft/yr. More than 80 percent of net evapotranspiration in the Lower Walker River basin was through evaporation from Walker Lake. Total evaporation from Walker Lake was about 161,000 acre-ft/yr and net evaporation was about 149,000 acre-ft/yr. Some previous estimates of evaporation from Walker Lake based on water-budget analysis actually represent total evaporation minus ground-water inflow to the lake. Historical evaporation rates determined on the basis of water budget analysis were less than the evaporation rate measured directly during this study. The difference could represent ground-water inflow to Walker Lake of 16,000 to 26,000 acre-ft/yr or could indicate that ground-water inflow to Walker Lake is decreasing over time as the lake perimeter recedes.

  18. Interaction of eta mesons with nuclei.

    PubMed

    Kelkar, N G; Khemchandani, K P; Upadhyay, N J; Jain, B K

    2013-06-01

    Back in the mid-1980s, a new branch of investigation related to the interaction of eta mesons with nuclei came into existence. It started with the theoretical prediction of possible exotic states of eta mesons and nuclei bound by the strong interaction and later developed into an extensive experimental program to search for such unstable states as well as understand the underlying interaction via eta-meson producing reactions. The vast literature of experimental as well as theoretical works that studied various aspects of eta-producing reactions such as the π(+)n → ηp, pd → (3)Heη, p (6)Li → (7)Be η and γ (3)He → η X, to name a few, had but one objective in mind: to understand the eta-nucleon (ηN) and hence the η-nucleus interaction which could explain the production data and confirm the existence of some η-mesic nuclei. In spite of these efforts, there remain uncertainties in the knowledge of the ηN and hence the η-nucleus interaction. Therefore, this review is an attempt to bind together the findings in these works and draw some global and specific conclusions which can be useful for future explorations.The ηN scattering length (which represents the strength of the η-nucleon interaction) using different theoretical models and analyzing the data on η production in pion, photon and proton induced reactions was found to be spread out in a wide range, namely, 0.18 ≤ Re aηN ≤ 1.03 fm and 0.16 ≤ Rm aηN ≤ 0.49 fm. Theoretical searches of heavy η-mesic nuclei based on η-nucleus optical potentials and lighter ones based on Faddeev type few-body approaches predict the existence of several quasibound and resonant states. Although some hints of η-mesic states such as (3)(η)He and (25)(η)Mg do exist from previous experiments, the promise of clearer signals for the existence of η-mesic nuclei lies in the experiments to be performed at the J-PARC, MAMI and COSY facilities in the near future. This review is aimed at giving an overall status

  19. Evapotranspiration estimation in heterogeneous urban vegetation

    NASA Astrophysics Data System (ADS)

    Nagler, P. L.; Nouri, H.; Beecham, S.; Anderson, S.; Sutton, P.; Chavoshi, S.

    2015-12-01

    Finding a valid approach to measure the water requirements of mixed urban vegetation is a challenge. Evapotranspiration (ET) is the main component of a plant's water requirement. A better understanding of the ET of urban vegetation is essential for sustainable urbanisation. Increased implementation of green infrastructure will be informed by this work. Despite promising technologies and sophisticated facilities, ET estimation of urban vegetation remains insufficiently characterized. We reviewed the common field, laboratory and modelling techniques for ET estimation, mostly agriculture and forestry applications. We opted for 3 approaches of ET estimation: 1) an observational-based method using adjustment factors applied to reference ET, 2) a field-based method of Soil Water Balance (SWB) and 3) a Remote Sensing (RS)-based method. These approaches were applied to an experimental site to evaluate the most suitable ET estimation approach for an urban parkland. To determine in-situ ET, 2 lysimeters and 4 Neutron Moisture Meter probes were installed. Based on SWB principles, all input water (irrigation, precipitation and upward groundwater movements) and output water (ET, drainage, soil moisture and runoff) were measured monthly for 14 months. The observation based approach and the ground-based approach (SWB) were compared. Our predictions were compared to the actual irrigation rates (data provided by the City Council). Results suggest the observational-based method is the most appropriate urban ET estimation. We examined the capability of RS to estimate ET for urban vegetation. Image processing of 5 WorldView2 satellite images enabled modelling of the relationship between urban vegetation and vegetation indices derived from high resolution images. Our results indicate that an ETobservational-based -NDVI modelling approach is a reliable method of ET estimation for mixed urban vegetation. It also has the advantage of not depending on extensive field data collection.

  20. Measurement of the gamma gamma* --> eta and gamma gamma* --> eta' transition form factors

    SciTech Connect

    del Amo Sanchez et al, P.

    2011-02-07

    We study the reactions e{sup +}e{sup -} {yields} e{sup +}e{sup -} {eta}{sup (/)} in the single-tag mode and measure the {gamma}{gamma}* {yields} {eta}{sup (/)} transition form factors in the momentum transfer range from 4 to 40 GeV{sup 2}. The analysis is based on 469 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.

  1. Evapotranspiration information reporting: II. Recommended documentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Researchers and journal authors, reviewers, and readers can benefit from more complete documentation of published evapotranspiration (ET) information, including a description of field procedures, instrumentation, data filtering, model parameterization, and site review. This information is important ...

  2. Mapping evapotranspiration in the Texas Panhandle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agriculture in the Texas High Plains accounts for approximately 92% of groundwater withdrawals. Because groundwater levels are declining in the region, efficient agricultural water use is imperative for sustainability and regional economic viability. Accurate regional evapotranspiration (ET) maps ...

  3. Estimating potential evapotranspiration with improved radiation estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potential evapotranspiration (PET) is of great importance to estimation of surface energy budget and water balance calculation. The accurate estimation of PET will facilitate efficient irrigation scheduling, drainage design, and other agricultural and meteorological applications. However, accuracy o...

  4. Remote Sensing of Snow and Evapotranspiration

    NASA Technical Reports Server (NTRS)

    Schmugge, T. (Editor)

    1985-01-01

    The use of snowmelt runoff models from both the U.S. and Japan for simulating discharge on basins in both countries is discussed as well as research in snowpack properties and evapotranspiration using remotely sensed data.

  5. First insights into disassembled "evapotranspiration"

    NASA Astrophysics Data System (ADS)

    Chormański, Jarosław; Kleniewska, Małgorzata; Berezowski, Tomasz; Szporak-Wasilewska, Sylwia; Okruszko, Tomasz; Szatyłowicz, Jan; Batelaan, Okke

    2015-04-01

    In this work we present an initial data analysis obtained from a complex tool for measuring water fluxes in wetland ecosystems. The tool was designed to quantify processes related to interception storage on plants leafs. The measurements are conducted by combining readings from various instruments, including: eddy covariance tower (EC), field spectrometer, SapFlow system, rain gauges above and under canopy, soil moisture probes and other. The idea of this set-up is to provide continuous measurement of overall water flux from the ecosystem (EC tower), intercepted water volume and timing (field spectrometers), through-fall (rain gauges above and under canopy), transpiration (SapFlow), evaporation and soil moisture (soil moisture probes). Disassembling the water flux to the above components allows giving more insight to the interception related processes and differentiates them fromthe total evapotranspiration. The measurements are conducted in the Upper Biebrza Basin (NE Poland). The study area is part of the valley and is covered by peat soils (mainly peat moss with the exception of areas near the river) and receives no inundations waters of the Biebrza. The plant community of Agrostietum-Carici caninae has a dominant share here creating an up to 0.6 km wide belt along the river. The area is covered also by Caricion lasiocarpae as well as meadows and pastures Molinio-Arrhenatheretea, Phragmitetum communis. Sedges form a hummock pattern characteristic for the sedge communities in natural river valleys with wetland vegetation. The main result of the measurement set-up will be the analyzed characteristics and dynamics of interception storage for sedge ecosystems and a developed methodology for interception monitoring by use spectral reflectance technique. This will give a new insight to processes of evapotranspiration in wetlands and its component transpiration, evaporation from interception and evaporation from soil. Moreover, other important results of this project

  6. Wetlands Evapotranspiration Using Remotely Sensed Solar Radiation

    NASA Astrophysics Data System (ADS)

    Jacobs, J. M.; Myers, D. A.; Anderson, M. C.

    2001-12-01

    The application of remote sensing methods to estimate evapotranspiration has the advantage of good spatial resolution and excellent spatial coverage, but may have the disadvantage of infrequent sampling and considerable expense. The GOES satellites provide enhanced temporal resolution with hourly estimates of solar radiation and have a spatial resolution that is significantly better than that available from most ground-based pyranometer networks. As solar radiation is the primary forcing variable in wetland evapotranspiration, the opportunity to apply GOES satellite data to wetland hydrologic analyses is great. An accuracy assessment of the remote sensing product is important and the subsequent validation of the evapotranspiration estimates are a critical step for the use of this product. A wetland field experiment was conducted in the Paynes Prairie Preserve, North Central Florida during a growing season characterized by significant convective activity. Evapotranspiration and other surface energy balance components of a wet prairie community dominated by Panicum hemitomon (maiden cane), Ptilimnium capillaceum (mock bishop's weed), and Eupatorium capillifolium (dog fennel) were investigated. Incoming solar radiation derived from GOES-8 satellite observations, in combination with local meteorological measurements, were used to model evapotranspiration from a wetland. The satellite solar radiation, derived net radiation and estimated evapotranspiration estimates were compared to measured data at 30-min intervals and daily times scales.

  7. The Self Actualized Reader.

    ERIC Educational Resources Information Center

    Marino, Michael; Moylan, Mary Elizabeth

    A study examined the commonalities that "voracious" readers share, and how their experiences can guide parents, teachers, and librarians in assisting children to become self-actualized readers. Subjects, 25 adults ranging in age from 20 to 67 years, completed a questionnaire concerning their reading histories and habits. Respondents varied in…

  8. Spectrophotometric Evolution of Eta Carinae's Great Eruption

    NASA Astrophysics Data System (ADS)

    Rest, Armin; Prieto, Jose Luis; Bianco, Federica; Matheson, Thomas; Smith, Nathan; Smith, Chris; Chornock, Ryan; Sinnott, Brendan; Welch, Douglas; Walborn, Nolan

    2013-06-01

    Eta Carinae is one of the most massive binaries in the Milky Way, and its expanding circumstellar nebula has been studied in detail. It was seen as the second brightest star in the sky during its 1800s "Great Eruption", but only visual estimates of its brightness were recorded. We discovered light echoes of the Great Eruption, which allowed us to obtain a spectrum of this event now, 150 years after it was first observed. We will present our new follow-up observations with which we have started to retrace its spectrophotometric evolution during and before the eruption.

  9. Measuring Evapotranspiration in Urban Irrigated Lawns in Two Kansas Cities

    NASA Astrophysics Data System (ADS)

    Shonkwiler, K. B.; Bremer, D.; Ham, J. M.

    2011-12-01

    Conservation of water is becoming increasingly critical in many metropolitan areas. The use of automated irrigation systems for the maintenance of lawns and landscapes is rising and these systems are typically maladjusted to apply more water than necessary, resulting in water wastage. Provision of accurate estimates of actual lawn water use may assist urbanites in conserving water through better adjustment of automatic irrigation systems. Micrometeorological methods may help determine actual lawn water use by measuring evapotranspiration (ET) from urban lawns. From April - August of 2011, four small tripod-mounted weather stations (tripods, five total) were deployed in twelve residential landscapes in the Kansas cities of Manhattan (MHK) and Wichita (ICT) in the USA (six properties in each city). Each tripod was instrumented to estimate reference crop evapotranspiration (ETo) via the FAO-56 method. During tripod deployment in residential lawns, actual evapotranspiration (ETactual) was measured nearby using a stationary, trailer-mounted eddy covariance (EC) station. The EC station sampled well-watered turf at the K-State Rocky Ford Turfgrass Center within 5 km of the study properties in MHK, and was also deployed at a commercial sod farm 15 - 40 km from the study residences in the greater ICT metro area. The fifth tripod was deployed in the source area of the EC station to estimate ETo in conjunction with tripods in the lawns (i.e., to serve as a reference). Data from EC allowed for computation of a so-called lawn coefficient (Kc) by determining the ratio of ETo from the tripods in residential lawns to ETo from the EC station (ETo,EC); hence, Kc = ETo,tripod / ETo,EC. Using this method, ETactual can be estimated for individual tripods within a lawn. Data suggests that it may be more accurate to quantify ET within individual lawns by microclimate (i.e., determine coefficients for "shaded" and "open/unshaded" portions of a lawn). By finding microclimate coefficients

  10. The effect of background hydrometeorological conditions on the sensitivity of evapotranspiration to model parameters: analysis with measurements from an Italian alpine catchment

    NASA Astrophysics Data System (ADS)

    Montaldo, N.; Toninelli, V.; Albertson, J. D.; Mancini, M.; Troch, P. A.

    Recent developments have made land-surface models (LSMs) more complex through the inclusion of more processes and controlling variables, increasing numbers of parameters and uncertainty in their estimates. To overcome these uncertainties, prior to applying a distributed LSM over the whole Toce basin (Italian Alps), a field campaign was carried out at an experimental plot within the basin before exploring the skill and parameter importance (sensitivity) using the TOPLATS model, an existing LSM. In the summer and autumn of 1999, which included both wet (atmosphere controlled) and dry (soil controlled) periods, actual evapotranspiration estimates were performed using Bowen ratio and, for a short period, eddy correlation methods. Measurements performed with the two methods are in good agreement. The calibrated LSM predicts actual evapotranspiration quite well over the whole observation period. A sensitivity analysis of the evapotranspiration to model parameters was performed through the global multivariate technique during both wet and dry periods of the campaign. This approach studies the influence of each parameter without conditioning on certain values of the other variables. Hence, all parameters are varied simultaneously using, for instance, a uniform sampling strategy through a Monte Carlo simulation framework. The evapotranspiration is highly sensitive to the soil parameters, especially during wet periods. However, the evapotranspiration is also sensitive to some vegetation parameters and, during dry periods, wilting point is the most critical for evapotranspiration predictions. This result confirms the importance of correct representation of vegetation properties which, in water-limited conditions, control evapotranspiration.

  11. Improved seasonal drought forecasts using reference evapotranspiration anomalies

    NASA Astrophysics Data System (ADS)

    McEvoy, Daniel J.; Huntington, Justin L.; Mejia, John F.; Hobbins, Michael T.

    2016-01-01

    A novel contiguous United States (CONUS) wide evaluation of reference evapotranspiration (ET0; a formulation of evaporative demand) anomalies is performed using the Climate Forecast System version 2 (CFSv2) reforecast data for 1982-2009. This evaluation was motivated by recent research showing ET0 anomalies can accurately represent drought through exploitation of the complementary relationship between actual evapotranspiration and ET0. Moderate forecast skill of ET0 was found up to leads of 5 months and was consistently better than precipitation skill over most of CONUS. Forecasts of ET0 during drought events revealed high categorical skill for notable warm-season droughts of 1988 and 1999 in the central and northeast CONUS, with precipitation skill being much lower or absent. Increased ET0 skill was found in several climate regions when CFSv2 forecasts were initialized during moderate-to-strong El Niño-Southern Oscillation events. Our findings suggest that ET0 anomaly forecasts can improve and complement existing seasonal drought forecasts.

  12. Evapotranspiration Cycles in a High Latitude Agroecosystem: Potential Warming Role.

    PubMed

    Ruairuen, Watcharee; Fochesatto, Gilberto J; Sparrow, Elena B; Schnabel, William; Zhang, Mingchu; Kim, Yongwon

    2015-01-01

    As the acreages of agricultural lands increase, changes in surface energetics and evapotranspiration (ET) rates may arise consequently affecting regional climate regimes. The objective of this study was to evaluate summertime ET dynamics and surface energy processes in a subarctic agricultural farm in Interior Alaska. The study includes micrometeorological and hydrological data. Results covering the period from June to September 2012 and 2013 indicated consistent energy fractions: LE/Rnet (67%), G/Rnet (6%), H/Rnet (27%) where LE is latent heat flux, Rnet is the surface net radiation, G is ground heat flux and H is the sensible heat flux. Additionally actual surface evapotranspiration from potential evaporation was found to be in the range of 59 to 66%. After comparing these rates with those of most prominent high latitude ecosystems it is argued here that if agroecosystem in high latitudes become an emerging feature in the land-use, the regional surface energy balance will significantly shift in comparison to existing Arctic natural ecosystems. PMID:26368123

  13. Evapotranspiration Cycles in a High Latitude Agroecosystem: Potential Warming Role

    PubMed Central

    Ruairuen, Watcharee

    2015-01-01

    As the acreages of agricultural lands increase, changes in surface energetics and evapotranspiration (ET) rates may arise consequently affecting regional climate regimes. The objective of this study was to evaluate summertime ET dynamics and surface energy processes in a subarctic agricultural farm in Interior Alaska. The study includes micrometeorological and hydrological data. Results covering the period from June to September 2012 and 2013 indicated consistent energy fractions: LE/Rnet (67%), G/Rnet (6%), H/Rnet (27%) where LE is latent heat flux, Rnet is the surface net radiation, G is ground heat flux and H is the sensible heat flux. Additionally actual surface evapotranspiration from potential evaporation was found to be in the range of 59 to 66%. After comparing these rates with those of most prominent high latitude ecosystems it is argued here that if agroecosystem in high latitudes become an emerging feature in the land-use, the regional surface energy balance will significantly shift in comparison to existing Arctic natural ecosystems. PMID:26368123

  14. Software Users Manual (SUM): Extended Testability Analysis (ETA) Tool

    NASA Technical Reports Server (NTRS)

    Maul, William A.; Fulton, Christopher E.

    2011-01-01

    This software user manual describes the implementation and use the Extended Testability Analysis (ETA) Tool. The ETA Tool is a software program that augments the analysis and reporting capabilities of a commercial-off-the-shelf (COTS) testability analysis software package called the Testability Engineering And Maintenance System (TEAMS) Designer. An initial diagnostic assessment is performed by the TEAMS Designer software using a qualitative, directed-graph model of the system being analyzed. The ETA Tool utilizes system design information captured within the diagnostic model and testability analysis output from the TEAMS Designer software to create a series of six reports for various system engineering needs. The ETA Tool allows the user to perform additional studies on the testability analysis results by determining the detection sensitivity to the loss of certain sensors or tests. The ETA Tool was developed to support design and development of the NASA Ares I Crew Launch Vehicle. The diagnostic analysis provided by the ETA Tool was proven to be valuable system engineering output that provided consistency in the verification of system engineering requirements. This software user manual provides a description of each output report generated by the ETA Tool. The manual also describes the example diagnostic model and supporting documentation - also provided with the ETA Tool software release package - that were used to generate the reports presented in the manual

  15. Hubble Space Telescope imaging of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Hester, J. J.; Westphal, James A.; Light, Robert M.; Currie, Douglas G.; Groth, Edward J.

    1991-01-01

    New high spatial resolution observations of the material around Eta Carinae, obtained with the Hubble Space Telescope Wide Field/Planetary Camera, are presented. The star Eta Carinae is one of the most massive and luminous stars in the Galaxy, and has been episodically expelling significant quantities of gas over the last few centuries. The morphology of the bright central nebulosity (the homunculus) indicates that it is a thin shell with very well defined edges, and is clumpy on 0.2 arcsec (about 10 to the 16th cm) scales. An extension to the northeast of the star (NN/NS using Walborn's 1976 nomenclature) appears to be a stellar jet and its associated bow shock. The bow shock is notable for an intriguing series of parallel linear features across its face. The S ridge and the W arc appear to be part of a 'cap' of emission located to the SW and behind the star. Together, the NE jet and the SW cap suggest that the symmetry axis for the system runs NE-SW rather than SE-NW, as previously supposed. Overall, the data indicate that the material around the star may represent an oblate shell with polar blowouts, rather than a bipolar flow.

  16. A LIGHTHOUSE EFFECT IN ETA CARINAE

    SciTech Connect

    Madura, Thomas I.; Groh, Jose H.

    2012-02-20

    We present a new model for the behavior of scattered time-dependent, asymmetric near-UV emission from the nearby ejecta of {eta} Car. Using a three-dimensional (3D) hydrodynamical simulation of {eta} Car's binary colliding winds, we show that the 3D binary orientation derived by Madura et al. in 2012 is capable of explaining the asymmetric near-UV variability observed in the Hubble Space Telescope Advanced Camera for Surveys/High Resolution Camera F220W images of Smith et al.. Models assuming a binary orientation with i Almost-Equal-To 130 Degree-Sign -145 Degree-Sign , {omega} Almost-Equal-To 230 Degree-Sign -315 Degree-Sign , P.A.{sub z} Almost-Equal-To 302 Degree-Sign -327 Degree-Sign are consistent with the observed F220W near-UV images. We find that the hot binary companion does not significantly contribute to the near-UV excess observed in the F220W images. Rather, we suggest that a bore-hole effect and the reduction of Fe II optical depths inside the wind-wind collision cavity carved in the extended photosphere of the primary star lead to the time-dependent directional illumination of circumbinary material as the companion moves about in its highly elliptical orbit.

  17. Far UV Spectroscopy of eta Carinae

    NASA Technical Reports Server (NTRS)

    Iping, R. C.; Sonneborn, G.; Massa, D.; Hutchings, J. B.; Gull, T. R.; Fisher, Richard (Technical Monitor)

    2000-01-01

    We present the first high spectral resolution observations of the Luminous Blue Variable eta Carinae between the Lyman limit and 1180 Angstroms. High resolution spectra (R approximately 20,000) were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite on Feb. 1 and Mar. 20, 2000. The observations were made with a 30x30 arcsec aperture and includes the entire Homunculus region. However, the spatial extent of the far UV flux is consistent with a point source. With the limited spatial resolution of the FUSE instrument, we can only constrain the far UV emission to be within +/-5 arcsec of the star. The far UV spectrum of eta Car is dominated by strong absorption features of molecular hydrogen. The observed flux level at 1150 Angstroms is approximately 4\\times 10(exp 12) erg/sq cm/s/Angstrom and decreases approximately linearly to approximately 920 Angstroms where converging HI and HII features completely blanket the spectrum. These observations were obtained as part of the FUSE Early Release Observation program.

  18. MID-CYCLE CHANGES IN ETA CARINAE

    SciTech Connect

    Martin, John C.; Davidson, Kris; Humphreys, Roberta M.; Mehner, Andrea

    2010-05-15

    In late 2006, ground-based photometry of {eta} Car plus the Homunculus showed an unexpected decrease in its integrated apparent brightness, an apparent reversal of its long-term brightening. Subsequent Hubble Space Telescope (HST)/WFPC2 photometry of the central star in the near-UV showed that this was not a simple reversal. This multi-wavelength photometry did not support increased extinction by dust as the explanation for the decrease in brightness. A spectrum obtained with the Gemini Multi-Object Spectrograph on the Gemini-South telescope revealed subtle changes mid-way in {eta} Car's 5.5 yr spectroscopic cycle when compared with HST/Space Telescope Imaging Spectrograph (STIS) spectra at the same phase in the cycle. At mid-cycle the secondary star is 20-30 AU from the primary. We suggest that the spectroscopic changes are consistent with fluctuations in the density and velocity of the primary star's wind, unrelated to the 5.5 yr cycle but possibly related to its latitude-dependent morphology. We also discuss subtle effects that must be taken into account when comparing ground-based and HST/STIS spectra.

  19. Far UV Spectroscopy of eta Carinae

    NASA Technical Reports Server (NTRS)

    Iping, R. C.; Sonneborn, G.; Massa, D. L.; Hutchings, J. B.; Gull, T. R.; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    We present the first high spectral resolution observations of the Luminous Blue Variable eta Carinae between the Lyman limit and 1180 A. High resolution spectra (R approx. 20,000) were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite on Feb. 1 and Mar. 20, 2000. The observations were made with a 30 x 30 arcsec aperture and includes the entire Homunculus region. However, the spatial extent of the far UV flux is consistent with a point source. With the limited spatial resolution of the FUSE instrument, we can only constrain the far UV emission to be within +/- 5 arcsec of the star. The far UV spectrum of eta Car is dominated by strong absorption features of molecular hydrogen. The observed flux level at 1150A is approx. 4 times 10(exp 12) erg /cm(exp -2) /sec(exp -1) / A(exp -1) and decreases approximately linearly to approx. 920 A where converging H1 and H2 features completely blanket the spectrum. These observations were obtained as part of the FUSE Early Release Observation program.

  20. Hubble Space Telescope imaging of Eta Carinae

    SciTech Connect

    Hester, J.J.; Westphal, J.A.; Light, R.M.; Currie, D.G.; Groth, E.J. Lick Observatory, Santa Cruz, CA Maryland Univ., College Park Princeton Univ., NJ )

    1991-08-01

    New high spatial resolution observations of the material around Eta Carinae, obtained with the Hubble Space Telescope Wide Field/Planetary Camera, are presented. The star Eta Carinae is one of the most massive and luminous stars in the Galaxy, and has been episodically expelling significant quantities of gas over the last few centuries. The morphology of the bright central nebulosity (the homunculus) indicates that it is a thin shell with very well defined edges, and is clumpy on 0.2 arcsec (about 10 to the 16th cm) scales. An extension to the northeast of the star (NN/NS using Walborn's 1976 nomenclature) appears to be a stellar jet and its associated bow shock. The bow shock is notable for an intriguing series of parallel linear features across its face. The S ridge and the W arc appear to be part of a 'cap' of emission located to the SW and behind the star. Together, the NE jet and the SW cap suggest that the symmetry axis for the system runs NE-SW rather than SE-NW, as previously supposed. Overall, the data indicate that the material around the star may represent an oblate shell with polar blowouts, rather than a bipolar flow. 26 refs.

  1. {eta}-Nucleon scattering length and effective range uncertainties

    SciTech Connect

    Green, A.M.; Wycech, S.

    2005-01-01

    The coupled {eta}N, {pi}N, {gamma}N, {pi}{pi}N system is described by a K-matrix method. The parameters in this model are adjusted to get an optimal fit to {pi}N{yields}{pi}N, {pi}N{yields}{eta}N, {gamma}N{yields}{pi}N, and {gamma}N{yields}{eta}N data in an energy range of about 100 MeV or so each side of the {eta} threshold. Compared with our earlier analysis, we now utilize recent Crystal Ball data. However, the outcome confirms our previous result that the {eta}-nucleon scattering length a is large with a value of 0.91(6)+i 0.27(2) fm.

  2. Branching Fraction and P-violation Charge Asymmetry Measurements for B-meson Decays to eta K+-, eta pi+-, eta'K, eta' pi+-, omega K, and omega pi+-

    SciTech Connect

    Aubert, B.

    2007-06-28

    The authors present measurements of the branching fractions for B{sup 0} meson decays to {eta}{prime}K{sup 0} and {omega}K{sup 0}, and of the branching fractions and CP-violation charge asymmetries for B{sup +} meson decays to {eta}{pi}{sup +}, {eta}K{sup +}, {eta}{prime}{pi}{sup +}, {eta}{prime}K{sup +}, {omega}{pi}{sup +}, and {omega}K{sup +}. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 383 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation. The measurements agree with previous results; they find no evidence for direct CP violation.

  3. Concerning the relationship between evapotranspiration and soil moisture

    NASA Technical Reports Server (NTRS)

    Wetzel, Peter J.; Chang, Jy-Tai

    1987-01-01

    The relationship between the evapotranspiration and soil moisture during the drying, supply-limited phase is studied. A second scaling parameter, based on the evapotranspirational supply and demand concept of Federer (1982), is defined; the parameter, referred to as the threshold evapotranspiration, occurs in vegetation-covered surfaces just before leaf stomata close and when surface tension restricts moisture release from bare soil pores. A simple model for evapotranspiration is proposed. The effects of natural soil heterogeneities on evapotranspiration computed from the model are investigated. It is observed that the natural variability in soil moisture, caused by the heterogeneities, alters the relationship between regional evapotranspiration and the area average soil moisture.

  4. Measurement of Branching Fractions in Radiative BDecays to eta K gamma and Search for B Decays to eta' K gamma

    SciTech Connect

    Aubert, B.

    2006-03-31

    The authors present measurements of the B {yields} {eta}K{gamma} branching fractions and upper limits for the B {yields} {eta}'K{gamma} branching fractions. For B{sup +} {yields} {eta}K{sup +}{gamma} they also measure the time-integrated charge asymmetry. The data sample, collected with the BABAR detector at the Stanford Linear Accelerator Center, represents 232 x 10{sup 6} produced B{bar B} pairs. The results for branching fractions and upper limits at 90% C.L. in units of 10{sup -6} are: {Beta}(B{sup 0} {yields} {eta}K{sup 0}{gamma}) = 11.3{sub -2.6}{sup +2.8} {+-} 0.6, {Beta}(B{sup +} {yields} {eta}K{sup +}{gamma}) = 10.0 {+-} 1.3 {+-} 0.5, {Beta}(B{sup 0} {yields} {eta}'K{sup 0}{gamma}) < 6.6, {Beta}(B{sup +} {yields} {eta}'K{sup +}{gamma}) < 4.2. The charge asymmetry in the decay B{sup +} {yields} {eta}K{sup +}{gamma} is {Alpha}{sub ch} = -0.09 {+-} 0.12 {+-} 0.01. The first errors are statistical and the second systematic.

  5. Chiral corrections to the anomalous 2{gamma} decays of {pi}{sup 0}, {eta} and {eta}{prime}

    SciTech Connect

    Issler, D.

    1990-11-01

    To any order in chiral perturbation theory, the anomalous Wess-Zumino term is shown to generate only chirally invariant counterterms. Explicit examples of 0(p{sub 6}) terms generated by one-loop graphs are given, some of which are relevant to the two-photon decays of {pi}{sup o}, {eta} and {eta}{prime}.

  6. Global daily reference evapotranspiration modeling and evaluation

    USGS Publications Warehouse

    Senay, G.B.; Verdin, J.P.; Lietzow, R.; Melesse, Assefa M.

    2008-01-01

    Accurate and reliable evapotranspiration (ET) datasets are crucial in regional water and energy balance studies. Due to the complex instrumentation requirements, actual ET values are generally estimated from reference ET values by adjustment factors using coefficients for water stress and vegetation conditions, commonly referred to as crop coefficients. Until recently, the modeling of reference ET has been solely based on important weather variables collected from weather stations that are generally located in selected agro-climatic locations. Since 2001, the National Oceanic and Atmospheric Administration's Global Data Assimilation System (GDAS) has been producing six-hourly climate parameter datasets that are used to calculate daily reference ET for the whole globe at 1-degree spatial resolution. The U.S. Geological Survey Center for Earth Resources Observation and Science has been producing daily reference ET (ETo) since 2001, and it has been used on a variety of operational hydrological models for drought and streamflow monitoring all over the world. With the increasing availability of local station-based reference ET estimates, we evaluated the GDAS-based reference ET estimates using data from the California Irrigation Management Information System (CIMIS). Daily CIMIS reference ET estimates from 85 stations were compared with GDAS-based reference ET at different spatial and temporal scales using five-year daily data from 2002 through 2006. Despite the large difference in spatial scale (point vs. ???100 km grid cell) between the two datasets, the correlations between station-based ET and GDAS-ET were very high, exceeding 0.97 on a daily basis to more than 0.99 on time scales of more than 10 days. Both the temporal and spatial correspondences in trend/pattern and magnitudes between the two datasets were satisfactory, suggesting the reliability of using GDAS parameter-based reference ET for regional water and energy balance studies in many parts of the world

  7. Evaluation of Water Stress Coefficient Methods to Estimate Actual Corn Evapotranspiration in Colorado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract for Kullberg Hydrology Days: Abstract. Increased competition for water resources is placing pressure on the agricultural sector to remain profitable while reducing water use. Remote sensing techniques have been developed to monitor crop water stress and produce information for evapotranspi...

  8. Estimation of actual evapotranspiration using measured and calculated values of bulk surface resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Currently the United Nations-Food and Agriculture Organization (FAO) recommends using the Penman-Monteith method for estimating ET over all other meteorological methods. The principal limitation of using the generalized form of the Penman-Monteith equation is in obtaining accurate values for the bu...

  9. Impact of Atmospheric Albedo on Amazon Evapotranspiration

    NASA Astrophysics Data System (ADS)

    Lopes, A. V.; Thompson, S. E.; Dracup, J. A.

    2013-12-01

    The vulnerability of the Amazon region to climate and anthropogenic driven disturbances has been the subject of extensive research efforts, given its importance in the global and regional climate and ecologic systems. The evaluation of such vulnerabilities requires the proper understanding of physical mechanisms controlling water and energy balances and how the disturbances change them. Among those mechanisms, the effects of atmospheric albedo on evapotranspiration have not been fully explored yet and are explored in this study. Evapotranspiration in the Amazon is sustained at high levels across all seasons and represents a large fraction of water and energy surface budgets. In this study, statistical analysis of data from four flux towers installed at Amazon primary forest sites was employed to quantify the impact of atmospheric albedo, mostly resulted from cloudiness, on evapotranspiration and to compare it to the effect of water limitation. Firstly, the difference in eddy-flux derived evapotranspiration at the flux towers under rainy and non-rainy antecedent conditions was tested for significance. Secondly, the same statistical comparison was performed under cloudy and clear sky conditions at hourly and daily time scales, using the reduction in incoming solar radiation as an indicator of cloudiness. Finally, the sensitivity of seasonal evapotranspiration totals to atmospheric albedo resulted from rainfall patterns is evaluated. That was done by sampling daily evapotranspiration estimates from empirical probability distribution functions conditioned to rainfall occurrence and then varying the number of dry days in each season. It was found that light limitation is much more important than water limitation in the Amazon, resulting in up to 43% reduction in daily evapotranspiration. Also, this effect varies by location and by season, the largest impact being in wet season, from December do January. Moreover, seasonal evapotranspiration totals were found to be

  10. Estimation of regional evapotranspiration for clear sky days over the North China Plain

    NASA Astrophysics Data System (ADS)

    Shu, Y.; Stisen, S.; Sandholt, I.; Jensen, K. H.

    2009-04-01

    The triangle method combined with thermal inertia for estimation of regional evapotranspiration based on Feng Yun-2C(FY-2C) satellite data and MODIS products over the North China Plain is presented. FY-2C, China's first operational geostationary meteorological satellite which features 5 spectral bands (1 VIS and 4 IR), can acquire one full disc image of China (60° N - 60° S ,45° E - 165° E) per hour every day. Two thermal red channels (IR1: 10.3-11.3 μm) and (IR2:11.5-12.5 μm) were used for surface temperature estimation using a split window algorithm originally proposed for the MSG-SEVIRI sensor assuming the channel response function range of the two split-window channels for MSG SEVIRI and FY-2C are similar and that the center of channels are the same. For application of the improved triangle method taking thermal inertia into account, the surface-air temperature gradient in the Ts-NDVI space, was replaced by the surface temperature temporal change estimated from the Land Surface Temperature at hours 8:00 and 12:00 in local time (ΔTs). Combined with the 16 days composite MODIS Vegetation Indices product (MOD 13) at spatial resolution of 5 km, evaporative fraction was estimated by interpolation in the ΔTs-NDVI triangular-shaped parameter space. Subsequently, regional actual evapotranspiration was estimated based on the derived evaporative fraction and available energy estimated from satellite data. In the piedmont plain with high NDVI and low ΔTs, evapotranspiration rate is high because of irrigation of winter wheat. In the coastal plain NDVI is low and also ΔTs is low as high evapotranspiration rates are sustained water supply from shallow water table. Ground-based measurements of evapotranspiration were retrieved from a lysimeter at the Luancheng eco-agricultural station of China Academy of Sciences. These data are representative for evapotranspiration in the piedmont plain and were used for validation of the actual evapotranspiration retrievals from

  11. Spatially distributed hydrotope-based modelling of evapotranspiration and runoff in mountainous basins

    NASA Astrophysics Data System (ADS)

    Gurtz, Joachim; Baltensweiler, Andri; Lang, Herbert

    1999-12-01

    River basins in mountainous regions are characterized by strong variations in topography, vegetation, soils, climatic conditions and snow cover conditions, and all are strongly related to altitude. The high spatial variation needs to be considered when modelling hydrological processes in such catchments. A complex hydrological model, with a great potential to account for spatial variability, was developed and applied for the hourly simulation of evapotranspiration, soil moisture, water balance and the runoff components for the period 1993 and 1994 in 12 subcatchments of the alpine/pre-alpine basin of the River Thur (area 1703 km2). The basin is located in the north-east of the Swiss part of the Rhine Basin and has an elevation range from 350 to 2500 m a.s.l. A considerable part of the Thur Basin is high mountain area, some of it above the tree-line and a great part of the basin is snow covered during the winter season.In the distributed hydrological model, the 12 sub-basins of the Thur catchment were spatially subdivided into sub-areas (hydrologically similar response units - HRUs or hydrotopes) using a GIS. Within the HRUs a hydrologically similar behaviour was assumed. Spatial interpolations of the meteorological input variables wereemployed for each altitudinal zone. The structure of the model components for snow accumulation and melt, interception, soil water storage and uptake by evapotranspiration, runoff generation and flow routing are briefly outlined. The results of the simulated potential evapotranspiration reflect the dominant role of altitudinal change in radiation and albedo of exposure, followed by the influence of slope. The actual evapotranspiration shows, in comparison with the potential evapotranspiration, a greater variability in the lower and medium altitudinal zones and a smaller variability in the upper elevation zones, which was associated with limitations of available moisture in soil and surface depression storages as well as with the

  12. Structure and mechanism of human DNA polymerase [eta

    SciTech Connect

    Biertümpfel, Christian; Zhao, Ye; Kondo, Yuji; Ramón-Maiques, Santiago; Gregory, Mark; Lee, Jae Young; Masutani, Chikahide; Lehmann, Alan R.; Hanaoka, Fumio; Yang, Wei

    2010-11-03

    The variant form of the human syndrome xeroderma pigmentosum (XPV) is caused by a deficiency in DNA polymerase {eta} (Pol{eta}), a DNA polymerase that enables replication through ultraviolet-induced pyrimidine dimers. Here we report high-resolution crystal structures of human Pol{eta} at four consecutive steps during DNA synthesis through cis-syn cyclobutane thymine dimers. Pol{eta} acts like a 'molecular splint' to stabilize damaged DNA in a normal B-form conformation. An enlarged active site accommodates the thymine dimer with excellent stereochemistry for two-metal ion catalysis. Two residues conserved among Pol{eta} orthologues form specific hydrogen bonds with the lesion and the incoming nucleotide to assist translesion synthesis. On the basis of the structures, eight Pol{eta} missense mutations causing XPV can be rationalized as undermining the molecular splint or perturbing the active-site alignment. The structures also provide an insight into the role of Pol{eta} in replicating through D loop and DNA fragile sites.

  13. Detection of a Hot Binary Companion of eta Carinae

    NASA Technical Reports Server (NTRS)

    Sonneborn, G.; Iping, R. C.; Gull, T. R.; Massa, D.; Hillier, D. J.

    2006-01-01

    A hot companion of eta Carinae has been detected using high resolution spectra (905 - 1 180 Angsroms) obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. Observations were obtained at two epochs of the 2024-day orbit: 2003 June during ingress to the 2003.5 X-ray eclipse and 2004 April several months after egress. These data show that essentially all the far-UV flux from eta Car shortward of Lyman alpha disappeared at least two days before the start of the X-ray eclipse (2003 June 29), implying that the hot companion, eta Car By was also eclipsed by the dense wind or extended atmosphere of eta Car A. Analysis of the far-UV spectrum shows that eta Car B is a luminous hot star. N II 1084-1086 emission disappears at the same time as the far-UV continuum, indicating that this feature originates from eta Car B itself or in close proximity to it. The strong N II emission also raises the possibility that the companion star is nitrogen rich. The observed FUV flux levels and spectral features, combined with the timing of their disappearance, are consistent with eta Carinae being a massive binary system.

  14. Detection of a Hot Binary Companion of eta Carinae

    NASA Technical Reports Server (NTRS)

    Sonnebom, G.; Iping, R. C.; Gull, T. R.; Massa, D. L.; Hillier, D. J.

    2006-01-01

    A hot companion of eta Carinae has been detected using high resolution spectra (905 - 1180 A) obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. Observations were obtained at two epochs of the 2024-day orbit: 2003 June during ingress to the 2003.5 X-ray eclipse and 2004 April several months after egress. These data show that essentially all the far-UV flux from eta Car shortward of Lyman alpha disappeared at least two days before the start of the X-ray eclipse (2003 June 29), implying that the hot companion, eta Car B, was also eclipsed by the dense wind or extended atmosphere of eta Car A. Analysis of the far-UV spectrum shows that eta Car B is a luminous hot star. N II 1084-1086 emission disappears at the same time as the far-UV continuum, indicating that this feature originates from eta Car B itself or in close proximity to it. The strong N II emission also raises the possibility that the companion star is nitrogen rich. The observed FUV flux levels and spectral features, combined with the timing of their disappearance, is consistent with eta Carinae being a massive binary system

  15. The Rapid Brightening of Eta Carinae

    NASA Astrophysics Data System (ADS)

    Martin, John C.; Davidson, Kris; Mehner, Andrea; Humphreys, Roberta M.

    2016-01-01

    Eta Carinae is one of the most dynamic and well-observed massive stars. Its bipolar Homunculus Nebula and other observations imply it has a strong latitude dependent stellar wind. The significant brightening of the star itself over the last two decades has been commonly explained as an evolution of the latitude structure of the wind , change in mass-loss rate, and/or clearing of circumstellar material in our direct line sight. Hubble Space Telescope images (with a much higher spatial resolution than ground-based images) document an increase in contrast between the brightness of the star and the Homunculus reflection nebula. We present measurements of the nebula's brightness, sampling the changing brightness of the star viewed from angles differing from our own direct line of sight. We also present ultraviolet photometry of the star synthesized from recent HST/STIS observations.

  16. eta Carinae Continues to Evolve (Abstract)

    NASA Astrophysics Data System (ADS)

    Martin, J. C.

    2015-06-01

    (Abstract only) Eta Carinae affords us a unique opportunity to study the pre-supernova evolution of the most massive stars. For at least the last half century, it has maintained a 5.5-year spectroscopic cycle that culminates with abrupt decreases in the strong stellar wind emission features. Over the last 15 years, the star has brightened at an accelerated rate and altered its spectrum, in addition to the spectroscopic cycle, indicating an ongoing change in state. We present Hubble Space Telescope spectroscopy and synthetic photometry from the most recent spectroscopic event (2014.5) that shows notable differences with past events and provides clues to the on-going evolution of the star.

  17. Vegetation impact on mean annual evapotranspiration at a global catchment scale

    NASA Astrophysics Data System (ADS)

    Peel, Murray C.; McMahon, Thomas A.; Finlayson, Brian L.

    2010-09-01

    Research into the role of catchment vegetation within the hydrologic cycle has a long history in the hydrologic literature. Relationships between vegetation type and catchment evapotranspiration and runoff were primarily assessed through paired catchment studies during the 20th century. Results from over 200 paired catchment studies from around the world have been reported in the literature. Two constraints on utilizing the results from paired catchment studies in the wider domain have been that the catchment areas studied are generally (1) small (<10 km2) and (2) from a narrow range of climate types. The majority of reported paired catchment studies are located in the USA (˜47%) and Australia (˜27%) and experience mainly temperate (Köppen C) and cold (Köppen D) climate types. In this paper we assess the impact of vegetation type on mean annual evapotranspiration through a large, spatially, and climatically diverse data set of 699 catchments from around the world. These catchments are a subset of 861 unregulated catchments considered for the analysis. Spatially averaged precipitation and temperature data, in conjunction with runoff and land cover information, are analyzed to draw broad conclusions about the vegetation impact on mean annual evapotranspiration. In this analysis any vegetation impact signal is assessed through differences in long-term catchment average actual evapotranspiration, defined as precipitation minus runoff, between catchments grouped by vegetation type. This methodology differs from paired catchment studies where vegetation impact is assessed through streamflow responses to a controlled, within catchment, land cover change. The importance of taking the climate type experienced by the catchments into account when assessing the vegetation impact on evapotranspiration is demonstrated. Tropical and temperate forested catchments are found to have statistically significant higher median evapotranspiration, by about 170 mm and 130 mm

  18. Comparison of wetland evapotranspiration estimates using diurnal groundwater fluctuations and measurements of a groundwater lysimeter

    NASA Astrophysics Data System (ADS)

    Fahle, Marcus; Dietrich, Ottfried; Lischeid, Gunnar

    2013-04-01

    Sound water management in wetlands requires knowledge of on-going processes and estimates of the water balance components. Specifically evapotranspiration is of crucial importance, as it is often the main water extracting quantity. To avoid elaborate and expensive equipment, which is often required for estimating actual values, potential evapotranspiration is frequently used, which can be easily derived from standard meteorological measurements. However, the potential values may under- or overestimate actual evapotranspiration significantly. A cheap and easy-to-use method for estimating actual values in shallow groundwater environments relies on diurnal groundwater fluctuation. Basically the 24 hours groundwater level decline, considering in some way the prevalent groundwater recovery, is multiplied by the readily available specific yield. Various varieties of this approach have been employed for that purpose, above all differing in their assumptions on groundwater recovery, i.e. lateral or vertical in- or outflow. The objective of our study is therefore to compare these different methods. For this purpose we use data of a weighable groundwater lysimeter situated at a ditch drained grassland site in the Spreewald wetland in Northeastern Germany. The groundwater level in the lysimeter was adjusted to a reference gauge and simulated the conditions of the surrounding area. Hence the lysimeter reflected near natural conditions and provided measurements of all water balance components with high temporal resolution (up to 10 minute intervals). Suitable days, i.e. with a pronounced diurnal fluctuation, of the vegetation periods 2011 and 2012 are chosen and used to prove common assumptions about groundwater recharge, e.g. if the values remain constant during the day or if diurnal variations resulting from gradient changes exist. Finally, based on the lysimeter measurements, the evapotranspiration estimates gained from different approaches that employ diurnal groundwater

  19. Error Sources in the ETA Energy Analyzer Measurement

    SciTech Connect

    Nexsen, W E

    2004-12-13

    At present the ETA beam energy as measured by the ETA energy analyzer and the DARHT spectrometer differ by {approx}12%. This discrepancy is due to two sources, an overestimate of the effective length of the ETA energy analyzer bending-field, and data reduction methods that are not valid. The discrepancy can be eliminated if we return to the original process of measuring the angular deflection of the beam and use a value of 43.2cm for the effective length of the axial field profile.

  20. Estimation of the parameters of ETAS models by Simulated Annealing

    PubMed Central

    Lombardi, Anna Maria

    2015-01-01

    This paper proposes a new algorithm to estimate the maximum likelihood parameters of an Epidemic Type Aftershock Sequences (ETAS) model. It is based on Simulated Annealing, a versatile method that solves problems of global optimization and ensures convergence to a global optimum. The procedure is tested on both simulated and real catalogs. The main conclusion is that the method performs poorly as the size of the catalog decreases because the effect of the correlation of the ETAS parameters is more significant. These results give new insights into the ETAS model and the efficiency of the maximum-likelihood method within this context. PMID:25673036

  1. A review of approaches for evapotranspiration partitioning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Partitioning of evapotranspiration (ET) into evaporation from the soil surface (E) and transpiration (T) is challenging but important in order to assess biomass production and the allocation of increasingly scarce water resources. Generally T is the desired component with the water being used to enh...

  2. Assessment of Texas evapotranspiration (ET) networks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to evaluate the current status of evapotranspiration (ET) data and networks in Texas for potential and beneficial conservation use with irrigation decision support systems. Objectives of this study included (1) identification of existing networks and the meteorological param...

  3. Evapotranspiration in Subtropical Climate: Measurements and predictions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration (ET) loss is estimated at about 80-85% of annual precipitation in South Florida. Accurate prediction of ET is an important part of the implementation of the Comprehensive Everglades Restoration Plan (CERP). In the USDA's Everglades Agro-Hydrology Model (EAHM), the daily soil root...

  4. Field measurement of cotton seedling evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information on cotton evapotranspiration (ET) during the seedling growth stage and under field conditions is scarce because ET is a difficult parameter to measure. Our objective was to use weighable lysimeters to measure daily values of cotton seedling ET. We designed and built plastic weighable mic...

  5. Spatial and temporal variation in evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatial and temporal variation in evapotranspiration occurs at multiple scales as the result of several different spatial and temporal patterns in precipitation, soil water holding capacity, cloudiness (available energy), types of crops, and residue and tillage management practices. We have often as...

  6. Evapotranspiration estimates using ASTER thermal infrared imagery

    NASA Astrophysics Data System (ADS)

    Schmugge, Thomas J.; French, Andrew; Kustas, William P.

    2002-01-01

    The recent availability of multi-band thermal infrared imagery from the Advanced Spaceborne Thermal Emission & Reflection radiometer (ASTER) on NASA's Terra satellite has made feasible the estimation of evapotranspiration at 90 meter resolution. One critical variable in evapotranspiration models is surface temperature. With ASTER the temperature can be reliably determined over a wide range of vegetative conditions. The requirements for accurate temperature measurement include minimization of atmospheric effects, correction for surface emissivity variations and sufficient resolution for the type of vegetative cover. When ASTER imagery are combined with meteorological observations, these requirements are usually met and result in surface temperatures accurate within 1-2 C. ASTER-based evapotranspiration estimates were made during September 2000 over a sub-humid regions at the USDA/ARS Grazinglands research laboratory near El Reno in central Oklahoma. Daily evapotranspiration was estimated by applying instantaneous ASTER surface temperatures, as well as ASTER-based vegetation indices from visible-near infrared bands, to a two-source energy flux model and combining the result with separately acquired hourly solar radiation data. The estimates of surface fluxes show reasonable agreement (within 50-100 W/m2) with ground-based Bowen Ratio Energy Balance measurements and illustrate how ASTER measurements can be applied to heterogeneous terrain. There are some significant discrepancies, however, and these may in part be due to difficulty quantifying fractional cover of senescent vegetation.

  7. {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma} and {eta} Prime {yields}{eta}{gamma}{gamma}: A primer analysis

    SciTech Connect

    Escribano, Rafel

    2012-10-23

    The electromagnetic rare decays {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma} and {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma} are analysed for the first time and their predicted branching ratios given. The vector meson exchange dominant contribution is treated using Vector Meson Dominance and the scalar component is estimated by means of the Linear Sigma Model. The agreement between our calculation and the measurement of the related process {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma} is a check of the procedure. Scalar meson effects are seen to be irrelevant for {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma}, while a significant scalar contribution due to the {sigma}(500) resonance seems to emerge in the case of {eta} Prime {yields}{pi}{sup 0}{gamma}{gamma}. Future measurements coming from KLOE-2, Crystal Ball, WASA, and BES-III will elucidate if any of these processes carry an important scalar contribution or they are simply driven by the exchange of vector mesons.

  8. Eta Meson Production in Proton-Proton and Nuclear Collisions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Dick, Frank

    2008-01-01

    Total cross sections for eta meson production in proton - proton collisions are calculated. The eta meson is mainly produced via decay of the excited nucleon resonance at 1535 MeV. A scalar quantum field theory is used to calculate cross sections, which also include resonance decay. Comparison between theory and experiment is problematic near threshold when resonance decay is not included. When the decay is included, the comparison between theory and experiment is much better.

  9. Reference Crop Evapotranspiration obtained from the geostationary satellite MSG (METEOSAT).

    NASA Astrophysics Data System (ADS)

    de Bruin, H. A. R.; Trigo, I. F.; Lorite, I. J.; Cruz-Blanco, M.; Gavilán, P.

    2012-04-01

    Among others, the scope of the Land Surface Analysis Satellite Applications Facility (LSA SAF) is to increase benefit from the EUMETSAT geostationary Satellites MSG data related to land, land-atmosphere interactions and biophysical applications. This is achieved by developing techniques, products and algorithms that will allow an effective use of MSG data, if needed, combined with data from numerical weather prediction models (e.g., ECMWF). Although directly designed to improve the observation of meteorological systems, the spectral characteristics, time resolution and area coverage offered by MSG allow for their use in a broad spectrum of other applications, for instance in agro- and hydrometeorology. This study concerns a method to determine how much water is needed for irrigation. Note that this is complementary to the actual evapotranspiration LSA SAF product. The objective of this study is to present a novel semi-empirical method to determine the Reference Crop Evapotranspiration (ET0) from the down-welling shortwave radiation and air temperature obtained through LSF SAF. ET0 is defined in the FAO Irrigation and Drainage report 56 (FAO56) and it is used to determine water requirements of agricultural crops in irrigated regions. It is evaluated with a special version of the Penman-Monteith equation (PM_FAO56) using data of a weather station installed over non-stressed grass. Such stations are expensive and very labor consuming. We developed our method for semi-arid regions where appropriate weather stations needed for FAO56 ET0 are missing. This concerns huge areas in the world. High-quality FAO-grass station near Cordoba, Spain were used, where, besides all input for PM-FAO56, independent lysimeter data are collected. In addition, it will be shown that significant errors in ET0 can occur if meteorological gathered over dry terrain will be used as input of PM-FAO56. For this purpose data sets obtained in different semi-arid regions will be analyzed.

  10. Simple analytical model of evapotranspiration in the presence of roots

    NASA Astrophysics Data System (ADS)

    Cejas, Cesare M.; Hough, L. A.; Castaing, Jean-Christophe; Frétigny, Christian; Dreyfus, Rémi

    2014-10-01

    Evaporation of water out of a soil involves complicated and well-debated mechanisms. When plant roots are added into the soil, water transfer between the soil and the outside environment is even more complicated. Indeed, plants provide an additional process of water transfer. Water is pumped by the roots, channeled to the leaf surface, and released into the surrounding air by a process called transpiration. Prediction of the evapotranspiration of water over time in the presence of roots helps keep track of the amount of water that remains in the soil. Using a controlled visual setup of a two-dimensional model soil consisting of monodisperse glass beads, we perform experiments on actual roots grown under different relative humidity conditions. We record the total water mass loss in the medium and the position of the evaporating front that forms within the medium. We then develop a simple analytical model that predicts the position of the evaporating front as a function of time as well as the total amount of water that is lost from the medium due to the combined effects of evaporation and transpiration. The model is based on fundamental principles of evaporation fluxes and includes empirical assumptions on the quantity of open stomata in the leaves, where water transpiration occurs. Comparison between the model and experimental results shows excellent prediction of the position of the evaporating front as well as the total mass loss from evapotranspiration in the presence of roots. The model also provides a way to predict the lifetime of a plant.

  11. Eta Carinae viewed from different vantages

    NASA Astrophysics Data System (ADS)

    Gull, T. R.

    2008-04-01

    The spatially-resolved winds of the massive binary, Eta Carinae, extend an arcsecond on the sky, well beyond the 10 to 20 milliarcsecond binary orbital dimension. Stellar wind line profiles, observed at very different angular resolutions of VLTI/AMBER, HST/STIS and VLT/UVES, provide spatial information on the extended wind interaction structure as it changes with orbital phase. These same wind lines, observable in the starlight scattered off the foreground lobe of the dusty Homunculus, provide time-variant line profiles viewed from significantly different angles. Comparisons of direct and scattered wind profiles observed in the same epoch and at different orbital phases provide insight on the extended wind structure and promise the potential for three-dimensional imaging of the outer wind structures. Massive, long-lasting clumps, including the nebularWeigelt blobs, originated during the two historical ejection events. Wind interactions with these clumps are quite noticeable in spatially-resolved spectroscopy. As the 2009.0 minimum approaches, analysis of existing spectra and 3-D modeling are providing bases for key observations to gain further understanding of this complex massive binary.

  12. Eta Carinae: Viewed from Multiple Vantage Points

    NASA Technical Reports Server (NTRS)

    Gull, Theodore

    2007-01-01

    The central source of Eta Carinae and its ejecta is a massive binary system buried within a massive interacting wind structure which envelops the two stars. However the hot, less massive companion blows a small cavity in the very massive primary wind, plus ionizes a portion of the massive wind just beyond the wind-wind boundary. We gain insight on this complex structure by examining the spatially-resolved Space Telescope Imaging Spectrograph (STIS) spectra of the central source (0.1") with the wind structure which extends out to nearly an arcsecond (2300AU) and the wind-blown boundaries, plus the ejecta of the Little Homunculus. Moreover, the spatially resolved Very Large Telescope/UltraViolet Echelle Spectrograph (VLT/UVES) stellar spectrum (one arcsecond) and spatially sampled spectra across the foreground lobe of the Homunculus provide us vantage points from different angles relative to line of sight. Examples of wind line profiles of Fe II, and the.highly excited [Fe III], [Ne III], [Ar III] and [S III)], plus other lines will be presented.

  13. Evidence for the eta_b(1S) in the Decay Upsilon(2S)-> gamma eta_b(1S)

    SciTech Connect

    Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Lopez, L.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Karlsruhe U., EKP /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /INFN, Naples /Naples U. /INFN, Naples /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /Pennsylvania U. /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DSM, DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Albany /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison

    2009-12-14

    We have performed a search for the {eta}{sub b}(1S) meson in the radiative decay of the {Upsilon}(2S) resonance using a sample of 91.6 million {Upsilon}(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E{sub {gamma}} = 610.5{sub -4.3}{sup +4.5}(stat) {+-} 1.8(syst) MeV, corresponding to an {eta}{sub b}(1S) mass of 9392.9{sub -4.8}{sup +4.6}(stat) {+-} 1.9(syst) MeV/c{sup 2}. The branching fraction for the decay {Upsilon}(2S) {yields} {gamma}{eta}{sub b}(1S) is determined to be (4.2{sub -1.0}{sup +1.1}(stat) {+-} 0.9(syst)) x 10{sup -4}. The ratio {Beta}({Upsilon}(2S) {yields} {gamma}{eta}{sub b}(1S))/{Beta}({Upsilon}(3S) {yields} {gamma}{eta}{sub b}(1S)) = 0.89{sub -0.23}{sup +0.25}(stat){sub -0.16}{sup +0.12}(syst) is consistent with the ratio expected for magnetic dipole transitions to the {eta}{sub b}(1S) meson.

  14. Inteligent estimation of daily evapotranspiration susing

    NASA Astrophysics Data System (ADS)

    Sharifan, H.; Dehghani, A. A.

    2009-04-01

    Evapotranspiration (ET) is one of the parameters in water resources management which is attractive for design of irrigation systems. Due to interaction between meteorology parameter, there are nonlinear relations for assessing the evapotraqnspiration. Artifical neural networks are innovative approaches for estimation and prediction by using learning concept. In this study, by using the daily data of Gorgan synoptical station in Golestan province/ Iran the multilayer perceptron with back propagation learning rule was trained. Five different ANN models comprision various combinations of daily climate variable, i. e. air temperature, sunshine, wind speed and humidity was developed to evaluate degree of effect of each input variables on ET. A comparison is made between the estimated provide by ANN models and ET-values estimated by FAO-Penman-Monteith (F-P-M) method. The results show that ANN models perform better than experimental relation. Keyword : Evapotranspiration, Artifical neural network, Penman-Manteith, Gorgan.

  15. The Artificial Neural Network Estimation for Daily and Hourly Rice Evapotranspiration in the Region of Red Soil, South China

    NASA Astrophysics Data System (ADS)

    Jing, Yuanshu; Ruthaikarn, Buaphean; Jin, Xinyi; Pang, Bo

    The evapotranspiration estimation is a key item for irrigation program. It has the important practical significance for high stable yield and water-saving in the region of red soil, South China. Penman-Monteith equation, recommended by FAO, is verified to be the most effective calculation to actual evaporation in many regions of the world. The only default is it has to use complete meteorological factors. To solve this problem, we are trying to find out a artificial neural network model (ANN) which can easily get its information and easy to calculate as well as guaranteed accuracy. A Bowen ratio energy balance (BREB) system and automatic weather station were employed for simultaneous measurement of actual evapotranspiration above the rice field. The frequency of 20-min recording provided the possibility for the estimation of daily and hourly evapotranspiration. The determined coefficient from the artificial neural network model on daily scale R2 is 0.9642, while hourly scale R2 is 0.9880. The reason was that the hourly scale training samples was greater than the daily scale measures. In general, the model gives an effective and feasible way for the evaluation of paddy rice evapotranspiration by the conventional parameters.

  16. Investigation of Valiantzas' evapotranspiration equation in Iran

    NASA Astrophysics Data System (ADS)

    Valipour, Mohammad

    2015-07-01

    Several methods are available to estimate the reference evapotranspiration including mass transfer-based, radiation-based, temperature-based, and pan evaporation-based methods. The most important weather parameters are solar radiation, temperature, relative humidity, and wind speed for evapotranspiration models. This study aims to compare five forms of Valiantzas' evapotranspiration methods (one of the newest models) as well as Priestley-Taylor and Turc models to detect the best one under different weather conditions. For this purpose, weather data were gathered from 181 synoptic stations in 31 provinces of Iran. The reference evapotranspiration was compared with the FAO Penman-Monteith method. The results show that they are suitable for provinces of Iran (coefficient of determination ( R 2) was more than 0.9900). The Valiantzas 1 ( T, R s, RH, u) is more suitable for centre and south of Iran (9 provinces), and the Valiantzas 2 ( T, R s, RH, u) is suitable for west, east, and north of Iran (22 provinces). The most precise method was the Valiantzas 1 ( T, R s, RH, u) for ES. In addition, among limited data methods, the Valiantzas 2 ( T, R s, RH) is the best method (18 provinces). Finally, a list of the best performances of each method was presented to use other regions according to values of temperature, relative humidity, solar radiation, and wind speed. The best weather conditions for use in Valiantzas' methods are >24.2 MJ m-2 day-1, 16-18 °C, 40-50 %, and 1.50-2.50 m s-1 for solar radiation, temperature, relative humidity, and wind speed, respectively. Results are also useful for selecting the best model when researchers must apply these models on the basis of the available data.

  17. Evapotranspiration: Challenges in Measurement and Modeling

    NASA Astrophysics Data System (ADS)

    Amatya, Devendra; Sun, Ge; Gowda, Prasanna

    2014-07-01

    Evapotranspiration (ET) processes at the leaf-to-landscape scales have important controls and feedbacks for the regional and global climate systems through complex interactions among the Earth's atmospheric, hydrological, and biogeochemical cycles. Innovative methods, tools, and technologies for improved understanding and quantifying of ET are critical for adapting more effective management strategies to cope with the increasing demand for freshwater resources under global change.

  18. Comparative Analysis of Evapotranspiration Using Eddy Covariance

    NASA Astrophysics Data System (ADS)

    BAE, H.; Ji, H.; Lee, B.; Nam, K.; Jang, B.; Lee, C.; Jung, H.

    2013-12-01

    The eddy covariance method has been widely used to quantify evapotranspiration. However, independent measurements of energy components such as latent heat flux, sensible heat flux often lead to under-measurements, this is commonly known as a lack of closure of the surface energy balance. In response to this methodological problem, this study is addressed specifically to correction of the latent and heat sensible fluxes. The energy components observed in agricultural and grassland from January 2013 were measured using the eddy covariance method. As a result of the comparison of the available energy (Rn-G) with the sum of the latent and sensible heat fluxes, R-Squared values were 0.72 in the agricultural land, 0.78 in the grassland, indicating that the latent and sensible heat fluxes were under-measured. The obtained latent and sensible heat fluxes were then modified using the Bowen-ratio closure method. After this correction process, the values of the sum of the latent and sensible heat fluxes have increased by 39.7 percent in the agricultural land, 32.2 percent in the grassland respectively. Evapotranspiration will be calculated with both the unmodified and modified latent heat flux values, the results will be then thoroughly compared. The results will be finally verified by comparison with evapotranspiration obtained from energy balance based model.

  19. Evapotranspiration and microclimate at a low-level radioactive-waste disposal site in northwestern Illinois

    USGS Publications Warehouse

    Healy, R.W.; DeVries, M.P.; Sturrock, Alex M., Jr.

    1989-01-01

    From July 1982 through June 1984, a study was made of the evapotranspiration and microclimate at a low-level radioactive-waste disposal site near Sheffield, Bureau County, Illinois. Vegetation at the site consists of mixed pasture grasses, primarily awnless brome (Bromus inermis) and red clover (Trifoleum pratense). Three methods were used to estimate evapotranspiration: (1) an energy budget with the Bowen ratio, (2) an aerodynamic profile, and (3) a soil-based water budget. For the aerodynamic-profile method, sensible-heat flux was estimated by a profile equation and evapotranspiration was then calculated as the residual in the energy-balance equation. Estimates by the energy-budget and aerodynamic-profile methods were computed from hourly data and then summed by days and months. Yearly estimates (for March through November) by these methods were in close agreement: 648 and 626 millimeters, respectively. Daily estimates reach a maximum of about 6 millimeters. The water-budget method produced only monthly estimates based on weekly or biweekly soil-moisture content measurements. The yearly evapotranspiration estimated by this method (which actually included only the months of April through October) was 655 millimeters. The March-through-November average for the three methods of 657 millimeters was equivalent to 70 percent of total precipitation. Continuous measurements were made of incoming and reflected shortwave radiation, incoming and emitted longwave radiation, net radiation, soil-heat flux, soil temperature, horizontal windspeed, and wet- and dry-bulb air temperature. Windspeed and air temperature were measured at heights of 0.5 and 2.0 meters (and also at 1.0 meter after September 1983). Soilmoisture content of the soil zone was measured with a gamma-attenuation gage. Annual precipitation (938 millimeters) and average temperature (10.8 degrees Celsius) at the Sheffield site were virtually identical to long-term averages from nearby National Weather Service

  20. Chaperonin containing T-complex polypeptide subunit eta (CCT-eta) is a specific regulator of fibroblast motility and contractility.

    PubMed

    Satish, Latha; Johnson, Sandra; Wang, James H-C; Post, J Christopher; Ehrlich, Garth D; Kathju, Sandeep

    2010-01-01

    Integumentary wounds in mammalian fetuses heal without scar; this scarless wound healing is intrinsic to fetal tissues and is notable for absence of the contraction seen in postnatal (adult) wounds. The precise molecular signals determining the scarless phenotype remain unclear. We have previously reported that the eta subunit of the chaperonin containing T-complex polypeptide (CCT-eta) is specifically reduced in healing fetal wounds in a rabbit model. In this study, we examine the role of CCT-eta in fibroblast motility and contractility, properties essential to wound healing and scar formation. We demonstrate that CCT-eta (but not CCT-beta) is underexpressed in fetal fibroblasts compared to adult fibroblasts. An in vitro wound healing assay demonstrated that adult fibroblasts showed increased cell migration in response to epidermal growth factor (EGF) and platelet derived growth factor (PDGF) stimulation, whereas fetal fibroblasts were unresponsive. Downregulation of CCT-eta in adult fibroblasts with short inhibitory RNA (siRNA) reduced cellular motility, both basal and growth factor-induced; in contrast, siRNA against CCT-beta had no such effect. Adult fibroblasts were more inherently contractile than fetal fibroblasts by cellular traction force microscopy; this contractility was increased by treatment with EGF and PDGF. CCT-eta siRNA inhibited the PDGF-induction of adult fibroblast contractility, whereas CCT-beta siRNA had no such effect. In each of these instances, the effect of downregulating CCT-eta was to modulate the behavior of adult fibroblasts so as to more closely approximate the characteristics of fetal fibroblasts. We next examined the effect of CCT-eta modulation on alpha-smooth muscle actin (alpha-SMA) expression, a gene product well known to play a critical role in adult wound healing. Fetal fibroblasts were found to constitutively express less alpha-SMA than adult cells. Reduction of CCT-eta with siRNA had minimal effect on cellular beta-actin but

  1. Image of the Eta Carinae Nebula Taken by the High Energy Astronomy Observatory (HEAO)-2

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This image is an x-ray view of Eta Carinae Nebula showing bright stars taken with the High Energy Astronomy Observatory (HEAO)-2/Einstein Observatory. The Eta Carinae Nebula is a large and complex cloud of gas, crisscrossed with dark lanes of dust, some 6,500 light years from Earth. Buried deep in this cloud are many bright young stars and a very peculiar variable star. The HEAO-2, the first imaging and largest x-ray telescope built to date, was capable of producing actual photographs of x-ray objects. Shortly after launch, the HEAO-2 was nicknamed the Einstein Observatory by its scientific experimenters in honor of the centernial of the birth of Albert Einstein, whose concepts of relativity and gravitation have influenced much of modern astrophysics, particularly x-ray astronomy. The HEAO-2, designed and developed by TRW, Inc. under the project management of the Marshall Space Flight Center, was launched aboard an Atlas/Centaur launch vehicle on November 13, 1978.

  2. Investigating Landsat-derived forest evapotranspiration in the Amazon

    NASA Astrophysics Data System (ADS)

    Khand, K. B.; Numata, I.; Kjaersgaard, J.; Cochrane, M. A.

    2015-12-01

    Nearly half of annual rainfall in the Amazon rainforest region is returned to the atmosphere through evapotranspiration (ET). However, this land-atmosphere water vapor feedback in Amazonia has been continuously disturbed by anthropogenic influence and climate change such as severe drought events. While forest ET dynamics in the Amazon have been studied from both point estimates (or in-situ measurements) and regional land-surface models as well as coarse-spatial satellite data, finer spatial data is required to address the spatial variability of forest ET associated with both forest disturbances and extreme climate events. We use Landsat-based METRIC (Mapping Evapotranspiration at high Resolution with Internalized Calibration) model to generate high-resolution (30 m) ET products and investigate its potential to characterize local and regional ET behavior by comparison to ET calculated from flux tower data. METRIC estimates actual ET as residual of the surface energy balance and is applied to capture the spatial variability of forest ET. The flux tower data were collected at two sites with different forest types: Para with wet equatorial forest and Rondônia with seasonally dry tropical forest. Our study was conducted on the dry season of the years 2003 and 2005 for Para, and 2000 through 2002 for Rondônia as a function of data availability of both cloud-free Landsat images and meteorological data for METRIC processing. Daily gridded actual ET estimates from METRIC during the dry season were obtained using a cubic spline interpolation of ETrF (fraction of reference ET) values between the satellite image dates and multiplying by daily reference ET. Across the all study years, differences between the daily ET estimates for the selected image dates from METRIC and the flux towers were less than 1.2 mm/day, while on monthly basis, these averaged daily ET differences were much lower (< 0.5 mm). At Para, the correlation (R2) between the daily ET rates from METRIC and the

  3. Searching for Radial Velocity Variations in eta Carinae

    NASA Technical Reports Server (NTRS)

    Iping, R. C.; Sonneborn, G.; Gull, T. R.; Ivarsson, S.; Nielsen, K.

    2006-01-01

    A hot companion of eta Carinae has been detected using high resolution spectra (905 - 1180 A) obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite (see poster by Sonneborn et al.). Analysis of the far-UV spectrum shows that eta Car B is a luminous hot star. The N II 1084-86 emission feature indicates that the star may be nitrogen rich. The FUV continuum and the S IV 1073 P-Cygni wind line suggest that the effective temperature of eta Car B is at least 25,000 K. FUV spectra of eta Carinae were obtained with the FUSE satellite at 9 epochs between 2000 February and 2005 July. The data consists of 12 observations taken with the LWRS aperture (30x30 arcsec), three with the HIRS aperture (1.25x20 arcsec), and one MRDS aperture (4x20 arcsec). In this paper we discuss the analysis of these spectra to search for radial velocity variations associated with the 5.54-year binary orbit of Eta Car AB.

  4. Tracing the wind interface of the massive binary Eta Carinae

    NASA Astrophysics Data System (ADS)

    Nielsen, Krister

    2007-07-01

    The binarity of Eta Carinae has been debated for a long time, but most recent evidence favors a binary star interpretation. However, very little is known about the nature of the companion star. Over Eta Carinae's spectroscopic period many observable wind lines in the NUV/Optical region, have been shown to exhibit peculiar line profiles with unusual velocity shifts relative to the system velocity. Some of the lines are exclusively blue-shifted over the entire 5.54 yr cycle and their ionization/excitation imply formation in the interface between the two massive stars. Especially, the He I emission lines are mainly formed in the wind interface region. Since the wind momentum is much larger for the primary star than its companion, the wind interface is located fairly close to the companion. Consequently, by tracing the He I emission we can construct a radial velocity curve that will describe the motion of the companion star and will derive the relation between the masses of the binary system stars. Furthermore, we will measure velocity and intensity variations in H I and Fe II to further investigate the ionization/excitation structure throughout Eta Carinae's wind. The analysis of the central source of Eta Carinae, due to the closeness of the two stars in the binary system {30 AU} and the intervening matter in line-of-sight towards Eta Carinae, is extremely dependent on data obtained with high angular resolving power. The HST archival data is crucial for the continuance of this project.

  5. Excited Ejecta in Light of Sight from Eta Car

    NASA Technical Reports Server (NTRS)

    Vieira, G.; Gull, T. R.; Danks, A.

    2003-01-01

    In the NUV spectrum of Eta Car, we have resolved many narrow absorption lines of neutral and singly-ionized elements with the Space Telescope Imaging Spectrograph. We report for the first time the detection of interstellar vanadium in absorption, and many highly-excited absorption lines of Fe, Cr, Ti, Ni, Co, Mn, and Mg. These elements, normally tied up in dust grains in the ISM, are located within wall of the Homunculus within 20,000 A.U. of Eta Car. Stellar radiation and stellar wind are interacting with the wall. Dust is likely being modified and/or destroyed. Previous Homunculus studies have demonstrated that nitrogen is overabundant and that carbon and oxygen emission lines are weak, or non-existent. Are the large column densities of these heavy elements due to abundance effects, excitation mechanisms, or modified grains? We may gain insight as Eta Car goes through its spectroscopic minimum in the summer of 2003.

  6. Is the Ejecta of ETA Carinae Overabundant or Overexcited

    NASA Technical Reports Server (NTRS)

    Gull, Theodore; Davidson, Kris; Johansson, Sveneric; Damineli, Augusto; Ishibashi, Kaxunori; Corcoran, Michael; Hartman, Henrick; Viera, Gladys; Nielsen, Krister

    2003-01-01

    The ejecta of Eta Carinae, revealed by HST/STIS, are in a large range of physical conditions. As Eta Carinae undergoes a 5.52 period, changes occur in nebular emission and nebular absorption. "Warm" neutral regions, partially ionized regions, and fully ionized regions undergo significant changes. Over 2000 emission lines, most of Fe-like elements, have been indentified in the Weigelt blobs B and D. Over 500 emission lines have been indentified in the Strontium Filament. An ionized Little Homunculus is nestled within the neutral-shelled Homunculus. In line of sight, over 500 nebular absorption lines have been identified with up to twenty velocity components. STIS is following changes in many nebular emission and absorption lines as Eta Carinae approaches the minimum, predicted to be in June/July 2003, during the General Assembly. Coordinated observations with HST, CHANDRA, RXTE, FUSE, UVES/VLT, Gemini and other observatories are following this minimum.

  7. Ultraviolet and visual wavelength spectroscopy of gas around ETA Carinae

    NASA Technical Reports Server (NTRS)

    Davidson, K.; Dufour, R. J.; Walborn, N. R.; Gull, T. R.

    1986-01-01

    Observational results of Eta Carinae are reported, especially spectroscopy of the outer 'S condensation' supplemented by data on the homunculus and its core. Theoretical calculations of atmosphere/wind models and of the shock-heated S condensation are needed for a proper analysis of the data, but some simplified results are discussed. The helium abundance at the surface of Eta Car appears to be roughly 0.4, and most of the CNO is nitrogen. There does not appear to be any reason, at present, to alter the often quoted temperature estimate of 30,000 K for the radiating surface (which may or may not be the surface of the star itself). The presently observed mass loss rate is probably less than 10 exp -2.4 solar masses/yr if the outflow is not strongly direction-dependent. Finally, a largely forgotten but highly relevant historical conjecture concerning Eta Car is mentioned.

  8. 75 FR 53982 - Proposed Information Collection Request of the ETA 207, Nonmonetary Determination Activities...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-02

    ... Determination Activities Report; Comment Request on Extension Without Change (OMB 1205-0150) AGENCY: Employment... . SUPPLEMENTARY INFORMATION: I. Background: The ETA 207 Report, Nonmonetary Determination Activities, contains... proposed extension collection of the ETA 207, Nonmonetary Determinations Activities Report. Comments...

  9. 76 FR 12760 - Comment Request for Information Collection for Report ETA 902, Disaster Unemployment Assistance...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-08

    ..., Disaster Unemployment Assistance Activities (OMB Control No. 1205- 0051): Extension Without Change AGENCY... ETA 902, Disaster Unemployment Assistance Activities under the Robert T. Stafford Disaster Relief and.... Background The ETA 902 Report, Disaster Unemployment Assistance (DUA) Activities, is a monthly...

  10. Study of evapotranspiration and evaporation beneath the canopy in a buckwheat field

    NASA Astrophysics Data System (ADS)

    Yan, Haofang; Zhang, Chuan; Oue, Hiroki; Wang, Guoqing; He, Bin

    2015-11-01

    The determination of evaporation and transpiration separately is very important in improving water use efficiency and developing exact irrigation scheduling. Hourly crop evapotranspiration ( ET c) and soil evaporation ( E g) beneath the buckwheat canopy were measured using Bowen ratio energy balance method and micro-lysimeters, respectively. The total ET c and E g in the whole growth season of buckwheat were 187.4 and 72.1 mm, respectively. Crop coefficient of buckwheat plant was simulated by days after sowing (DAS) and leaf area index (LAI), the average values for four growth stages were 0.58, 0.59, 1.10, and 0.74; and soil evaporation coefficient (the ratio of soil evaporation to reference evapotranspiration) was modeled by soil water content at 5-cm depth by dividing the LAI into two stages. The relationship between the ratio of soil evaporation to actual evapotranspiration ( E g/ ET c) and LAI was decided. It was found that E g/ ET c decreased from 1 to 0.3 with the increase in LAI.

  11. The Role of Evapotranspiration on Soil Moisture Depletion in a Small Alaskan Subarctic Farm

    NASA Astrophysics Data System (ADS)

    Ruairuen, W.; Fochesatto, G. J.; Sparrow, E. B.; Schnabel, W.; Zhang, M.

    2013-12-01

    At high latitudes the period for agriculture production is very short (110 frost-free days) and strongly depends on the availability of soil water content for vegetables to grow. In this context the evapotranspiration (ET) cycle is key variable underpinning mass and energy balance modulating therefore moisture gradients and soil dryness. Evapotranspiration (ET) from field-grown crops water stress is virtually unknown in the subarctic region. Understanding ET cycles in high latitude agricultural ecosystem is essential in terms of water management and sustainability and projection of agricultural activity. To investigate the ET cycle in farming soils a field experiment was conducted in the summer of 2012 and 2013 at the University of Alaska Fairbanks Agricultural and Forestry Experiment Station combining micrometeorological and hydrological measurements. In this case experimental plots of lettuce (Lactuca sativa) plants were grown. The experiment evaluated several components of the ET cycle such as actual evapotranspiration, reference evaporation, pan evaporation as well as soil water content and temperature profiles to link them to the vegetable growing functions. We investigated the relationship of soil moisture content and crop water use across the growing season as a function of the ET cycle. Soil water depletion was compared to daily estimates of water loss by ET during dry and wet periods. We also investigated the dependence of ET on the atmospheric boundary layer flow patterns set by the synoptic large scale weather patterns.

  12. Remote sensing of evapotranspiration using automated calibration: Development and testing in the state of Florida

    NASA Astrophysics Data System (ADS)

    Evans, Aaron H.

    Thermal remote sensing is a powerful tool for measuring the spatial variability of evapotranspiration due to the cooling effect of vaporization. The residual method is a popular technique which calculates evapotranspiration by subtracting sensible heat from available energy. Estimating sensible heat requires aerodynamic surface temperature which is difficult to retrieve accurately. Methods such as SEBAL/METRIC correct for this problem by calibrating the relationship between sensible heat and retrieved surface temperature. Disadvantage of these calibrations are 1) user must manually identify extremely dry and wet pixels in image 2) each calibration is only applicable over limited spatial extent. Producing larger maps is operationally limited due to time required to manually calibrate multiple spatial extents over multiple days. This dissertation develops techniques which automatically detect dry and wet pixels. LANDSAT imagery is used because it resolves dry pixels. Calibrations using 1) only dry pixels and 2) including wet pixels are developed. Snapshots of retrieved evaporative fraction and actual evapotranspiration are compared to eddy covariance measurements for five study areas in Florida: 1) Big Cypress 2) Disney Wilderness 3) Everglades 4) near Gainesville, FL. 5) Kennedy Space Center. The sensitivity of evaporative fraction to temperature, available energy, roughness length and wind speed is tested. A technique for temporally interpolating evapotranspiration by fusing LANDSAT and MODIS is developed and tested. The automated algorithm is successful at detecting wet and dry pixels (if they exist). Including wet pixels in calibration and assuming constant atmospheric conductance significantly improved results for all but Big Cypress and Gainesville. Evaporative fraction is not very sensitive to instantaneous available energy but it is sensitive to temperature when wet pixels are included because temperature is required for estimating wet pixel

  13. The 2011 Eta-Aquariids observing campaign from La Palma

    NASA Astrophysics Data System (ADS)

    Bettonvil, Felix; Weiland, Thomas

    2013-01-01

    Because the Eta-Aquariids, the most prominent stream for Southern Hemisphere observers, are difficult to watch from mid-northern latitudes, a week-long visual observing campaign was carried out in May 2011 from La Palma, Canary Islands, Spain. There, on the grounds of the Observatorio del Roque de Los Muchachos (ORM), at an altitude of more than 2000 m above sea level, observing conditions were nearly perfect. As a consequence, we managed to record more than 300 Eta-Aquariids in about 30 hours of effective observing time. An impression of the campaign together with a summary of the results is given.

  14. Start of Eta Car's X-ray Minimum

    NASA Technical Reports Server (NTRS)

    Corcoran, Michael F.; Liburd, Jamar; Hamaguchi, Kenji; Gull, Theodore; Madura, Thomas; Teodoro, Mairan; Moffat, Anthony; Richardson, Noel; Russell, Chris; Pollock, Andrew; Owocki, Stan

    2014-01-01

    Analysis of Eta Car's X-ray spectrum in the 2-10 keV band using quicklook data from the XRay Telescope on Swift shows that the flux on July 30, 2014 was 4.9 plus or minus 2.0×10(exp-12) ergs s(exp-1)cm(exp-2). This flux is nearly equal to the X-ray minimum flux seen by RXTE in 2009, 2003.5, and 1998, and indicates that Eta Car has reached its X-ray minimum, as expected based on the 2024-day period derived from previous 2-10 keV observations with RXTE.

  15. DARHT II Scaled Accelerator Tests on the ETA II Accelerator*

    SciTech Connect

    Weir, J T; Anaya Jr, E M; Caporaso, G J; Chambers, F W; Chen, Y; Falabella, S; Lee, B S; Paul, A C; Raymond, B A; Richardson, R A; Watson, J A; Chan, D; Davis, H A; Day, L A; Scarpetti, R D; Schultze, M E; Hughes, T P

    2005-05-26

    The DARHT II accelerator at LANL is preparing a series of preliminary tests at the reduced voltage of 7.8 MeV. The transport hardware between the end of the accelerator and the final target magnet was shipped to LLNL and installed on ETA II. Using the ETA II beam at 5.2 MeV we completed a set of experiments designed reduce start up time on the DARHT II experiments and run the equipment in a configuration adapted to the reduced energy. Results of the beam transport using a reduced energy beam, including the kicker and kicker pulser system will be presented.

  16. Evapotranspiration and microclimate at a low-level radioactive-waste disposal site in northwestern Illinois

    USGS Publications Warehouse

    Healy, R.W.; DeVries, M.P.; Sturrock, A.M.

    1987-01-01

    From July 1982 through June 1984, a study was made of the microclimate and evapotranspiration at a low-level radioactive-waste disposal site near Sheffield, Bureau County, Illinois. Vegetation at the site consists of mixed pasture grasses, primarily brome (Bromus inermis) and red clover (Trifoleum pratense). Three methods were used to estimate evapotranspiration: (1) an energy-budget with the Bowen ratio, (2) an aerodynamic-profile, and (3) a soil-based water-budget. For the aerodynamic-profile method, sensible-heat flux was estimated by a profile equation and evapotranspiration was then calculated as the residual in the energy-balance equation. Estimates by the energy-budget and aerodynamic-profile methods were computed from hourly data, then summed by days and months. Yearly estimates for March through November, by these methods, were quite close--648 and 626 millimeters, respectively. Daily estimates range up to a maximum of about 6 millimeters. The water-budget method produced only monthly estimates based on weekly or biweekly soil-moisture content measurements. The yearly evapotranspiration estimated by this method (which actually included only the months of April through October) was 655 millimeters. The March-through-November average for the three methods of 657 millimeters was equivalent to 70 percent of precipitation. Continuous measurements were made of incoming and reflected shortwave radiation, incoming and emitted longwave radiation, net radiation, soil-heat flux, soil temperature, horizontal windspeed, and wet- and dry-bulb air temperature. Windspeed and air temperature were measured at heights of 0.5 and 2.0 meters (and also at 1.0 meter after September 1983). Soil-moisture content of the soil zone was measured with a gamma-attenuation gage. Annual precipitation (938 millimeters) and average temperature (10.8 degrees Celsius) were virtually identical to long-term averages from nearby National Weather Service stations. Solar radiation averaged 65

  17. A new DSSAT-CSM evapotranspiration module: ASCE standardized reference evapotranspiration with dual crop coefficient

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although the DSSAT-CSM series of crop models have been used for decades, new focus has been put on improving evapotranspiration (ET) simulation in crop models. A new ET module was added to the model code to calculate potential ET, which combines the ASCE Standardized Reference ET (both grass and alf...

  18. Combining surface reanalysis and remote sensing data for monitoring evapotranspiration

    USGS Publications Warehouse

    Marshall, M.; Tu, K.; Funk, C.; Michaelsen, J.; Williams, Pat; Williams, C.; Ardö, J.; Marie, B.; Cappelaere, B.; Grandcourt, A.; Nickless, A.; Noubellon, Y.; Scholes, R.; Kutsch, W.

    2012-01-01

    Climate change is expected to have the greatest impact on the world's poor. In the Sahel, a climatically sensitive region where rain-fed agriculture is the primary livelihood, expected decreases in water supply will increase food insecurity. Studies on climate change and the intensification of the water cycle in sub-Saharan Africa are few. This is due in part to poor calibration of modeled actual evapotranspiration (AET), a key input in continental-scale hydrologic models. In this study, a model driven by dynamic canopy AET was combined with the Global Land Data Assimilation System realization of the NOAH Land Surface Model (GNOAH) wet canopy and soil AET for monitoring purposes in sub-Saharan Africa. The performance of the hybrid model was compared against AET from the GNOAH model and dynamic model using eight eddy flux towers representing major biomes of sub-Saharan Africa. The greatest improvements in model performance are at humid sites with dense vegetation, while performance at semi-arid sites is poor, but better than individual models. The reduction in errors using the hybrid model can be attributed to the integration of a dynamic vegetation component with land surface model estimates, improved model parameterization, and reduction of multiplicative effects of uncertain data.

  19. Adequacy of selected evapotranspiration approximations for hydrologic simulation

    USGS Publications Warehouse

    Sumner, D.M.

    2006-01-01

    Evapotranspiration (ET) approximations, usually based on computed potential ET (PET) and diverse PET-to-ET conceptualizations, are routinely used in hydrologic analyses. This study presents an approach to incorporate measured (actual) ET data, increasingly available using micrometeorological methods, to define the adequacy of ET approximations for hydrologic simulation. The approach is demonstrated at a site where eddy correlation-measured ET values were available. A baseline hydrologic model incorporating measured ET values was used to evaluate the sensitivity of simulated water levels, subsurface recharge, and surface runoff to error in four ET approximations. An annually invariant pattern of mean monthly vegetation coefficients was shown to be most effective, despite the substantial year-to-year variation in measured vegetation coefficients. The temporal variability of available water (precipitation minus ET) at the humid, subtropical site was largely controlled by the relatively high temporal variability of precipitation, benefiting the effectiveness of coarse ET approximations, a result that is likely to prevail at other humid sites.

  20. 75 FR 3927 - Proposed Information Collection Request for the ETA 218, Benefit Rights and Experience Report...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-25

    ... Information Collection Request for the ETA 218, Benefit Rights and Experience Report; Comment Request on... unemployment compensation programs. The data in the ETA 218, Benefit Rights and Experience Report, includes... extension for the collection of the ETA 218, Benefit Rights and Experience report. Comments are...

  1. Current status of E/f sub 1 (1420) and. iota. /. eta. (1450)

    SciTech Connect

    Chung, S.U. )

    1989-09-01

    The current status and future prospects are given of the E/f{sub 1} (1420) and the {eta}(1430) region containing the {iota}/{eta}(1450). These states are seen in the channels K{bar K}{pi} and {eta}{pi}{pi}. 43 refs., 10 figs., 5 tabs.

  2. Evaluation of different methods to estimate daily reference evapotranspiration in ungauged basins in Southern Brazil

    NASA Astrophysics Data System (ADS)

    Ribeiro Fontoura, Jessica; Allasia, Daniel; Herbstrith Froemming, Gabriel; Freitas Ferreira, Pedro; Tassi, Rutineia

    2016-04-01

    Evapotranspiration is a key process of hydrological cycle and a sole term that links land surface water balance and land surface energy balance. Due to the higher information requirements of the Penman-Monteith method and the existing data uncertainty, simplified empirical methods for calculating potential and actual evapotranspiration are widely used in hydrological models. This is especially important in Brazil, where the monitoring of meteorological data is precarious. In this study were compared different methods for estimating evapotranspiration for Rio Grande do Sul, the Southernmost State of Brazil, aiming to suggest alternatives to the recommended method (Penman-Monteith-FAO 56) for estimate daily reference evapotranspiration (ETo) when meteorological data is missing or not available. The input dataset included daily and hourly-observed data from conventional and automatic weather stations respectively maintained by the National Weather Institute of Brazil (INMET) from the period of 1 January 2007 to 31 January 2010. Dataset included maximum temperature (Tmax, °C), minimum temperature (Tmin, °C), mean relative humidity (%), wind speed at 2 m height (u2, m s‑1), daily solar radiation (Rs, MJ m‑ 2) and atmospheric pressure (kPa) that were grouped at daily time-step. Was tested the Food and Agriculture Organization of the United Nations (FAO) Penman-Monteith method (PM) at its full form, against PM assuming missing several variables not normally available in Brazil in order to calculate daily reference ETo. Missing variables were estimated as suggested in FAO56 publication or from climatological means. Furthermore, PM was also compared against the following simplified empirical methods: Hargreaves-Samani, Priestley-Taylor, Mccloud, McGuiness-Bordne, Romanenko, Radiation-Temperature, Tanner-Pelton. The statistical analysis indicates that even if just Tmin and Tmax are available, it is better to use PM estimating missing variables from syntetic data than

  3. Measurement of the Color-Suppressed B0->D(*)0 pi0 /omega/eta/eta Prime Branching Fractions

    SciTech Connect

    Prudent, X

    2008-11-05

    The authors report results on the branching fraction (BF) measurement of the color-suppressed decays {bar B}{sup 0} {yields} D{sup 0}{pi}{sup 0}, D*{sup 0}{pi}{sup 0}, D{sup 0}{eta}, D*{sup 0}{eta}, D{sup 0}{omega}, D*{sup 0}{omega}, D{sup 0}{eta}{prime}, and D*{sup 0}{eta}{prime}. They measure the branching fractions BF(D{sup 0}{pi}{sup 0}) = (2.78 {+-} 0.08 {+-} 0.20) x 10{sup -4}, BF(D*{sup 0}{pi}{sup 0}) = (1.78 {+-} 0.13 {+-} 0.23) x 10{sup -4}, BF(D{sup 0}{eta}) = (2.41 {+-} 0.09 {+-} 0.17) x 10{sup -4}, BF(D*{sup 0}{eta}) = (2.32 {+-} 0.13 {+-} 0.22) x 10{sup -4}, BF(D{sup 0}{omega}) = (2.77 {+-} 0.13 {+-} 0.22) x 10{sup -4}, BF(D*{sup 0}{omega}) = (4.44 {+-} 0.23 {+-} 0.61) x 10{sup -4}, BF(D{sup 0}{eta}{prime}) = (1.38 {+-} 0.12 {+-} 0.22) x 10{sup -4} and BF(D*{sup 0}{eta}{prime}) = (1.29 {+-} 0.23 {+-} 0.23) x 10{sup -4}, where the first uncertainty is statistical and the second is systematic. The result is based on a sample of (454 {+-} 5) x 10{sup 6} B{bar B} pairs collected at the {Upsilon}(4S) resonance from 1999 to 2007, with the BABAR detector at the PEP-II storage rings at the Stanford Linear Accelerator Center. The measurements are compared to theoretical predictions by factorization, SCET and pQCD. The presence of final state interactions predictions by factorization, SCET and pQCD. The presence of final state interactions is confirmed and the measurements seem to be more in favor of SCET compared to pQCD.

  4. Estimating seasonal evapotranspiration from temporal satellite images

    USGS Publications Warehouse

    Singh, Ramesh K.; Liu, Shu-Guang; Tieszen, Larry L.; Suyker, Andrew E.; Verma, Shashi B.

    2012-01-01

    Estimating seasonal evapotranspiration (ET) has many applications in water resources planning and management, including hydrological and ecological modeling. Availability of satellite remote sensing images is limited due to repeat cycle of satellite or cloud cover. This study was conducted to determine the suitability of different methods namely cubic spline, fixed, and linear for estimating seasonal ET from temporal remotely sensed images. Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC) model in conjunction with the wet METRIC (wMETRIC), a modified version of the METRIC model, was used to estimate ET on the days of satellite overpass using eight Landsat images during the 2001 crop growing season in Midwest USA. The model-estimated daily ET was in good agreement (R2 = 0.91) with the eddy covariance tower-measured daily ET. The standard error of daily ET was 0.6 mm (20%) at three validation sites in Nebraska, USA. There was no statistically significant difference (P > 0.05) among the cubic spline, fixed, and linear methods for computing seasonal (July–December) ET from temporal ET estimates. Overall, the cubic spline resulted in the lowest standard error of 6 mm (1.67%) for seasonal ET. However, further testing of this method for multiple years is necessary to determine its suitability.

  5. Seasonal evapotranspiration patterns in mangrove forests

    NASA Astrophysics Data System (ADS)

    Barr, Jordan G.; DeLonge, Marcia S.; Fuentes, Jose D.

    2014-04-01

    Diurnal and seasonal controls on water vapor fluxes were investigated in a subtropical mangrove forest in Everglades National Park, Florida. Energy partitioning between sensible and latent heat fluxes was highly variable during the 2004-2005 study period. During the dry season, the mangrove forest behaved akin to a semiarid ecosystem as most of the available energy was partitioned into sensible heat, which gave Bowen ratio values exceeding 1.0 and minimum latent heat fluxes of 5 MJ d-1. In contrast, during the wet season the mangrove forest acted as a well-watered, broadleaved deciduous forest, with Bowen ratio values of 0.25 and latent heat fluxes reaching 18 MJ d-1. During the dry season, high salinity levels (> 30 parts per thousand, ppt) caused evapotranspiration to decline and correspondingly resulted in reduced canopy conductance. From multiple linear regression, daily average canopy conductance to water vapor declined with increasing salinity, vapor pressure deficit, and daily sums of solar irradiance but increased with air temperature and friction velocity. Using these relationships, appropriately modified Penman-Monteith and Priestley-Taylor models reliably reproduced seasonal trends in daily evapotranspiration. Such numerical models, using site-specific parameters, are crucial for constructing seasonal water budgets, constraining hydrological models, and driving regional climate models over mangrove forests.

  6. Satellite-based monitoring of cotton evapotranspiration

    NASA Astrophysics Data System (ADS)

    Dalezios, Nicolas; Dercas, Nicholas; Tarquis, Ana Maria

    2016-04-01

    Water for agricultural use represents the largest share among all water uses. Vulnerability in agriculture is influenced, among others, by extended periods of water shortage in regions exposed to droughts. Advanced technological approaches and methodologies, including remote sensing, are increasingly incorporated for the assessment of irrigation water requirements. In this paper, remote sensing techniques are integrated for the estimation and monitoring of crop evapotranspiration ETc. The study area is Thessaly central Greece, which is a drought-prone agricultural region. Cotton fields in a small agricultural sub-catchment in Thessaly are used as an experimental site. Daily meteorological data and weekly field data are recorded throughout seven (2004-2010) growing seasons for the computation of reference evapotranspiration ETo, crop coefficient Kc and cotton crop ETc based on conventional data. Satellite data (Landsat TM) for the corresponding period are processed to estimate cotton crop coefficient Kc and cotton crop ETc and delineate its spatiotemporal variability. The methodology is applied for monitoring Kc and ETc during the growing season in the selected sub-catchment. Several error statistics are used showing very good agreement with ground-truth observations.

  7. National Weather Service Forecast Reference Evapotranspiration

    NASA Astrophysics Data System (ADS)

    Osborne, H. D.; Palmer, C. K.; Krone-Davis, P.; Melton, F. S.; Hobbins, M.

    2013-12-01

    The National Weather Service (NWS), Weather Forecasting Offices (WFOs) are producing daily reference evapotranspiration (ETrc) forecasts or FRET across the Western Region and in other selected locations since 2009, using the Penman - Monteith Reference Evapotranspiration equation for a short canopy (12 cm grasses), adopted by the Environmental Water Resources Institute of the American Society of Civil Engineers (ASCE-EWRI, 2004). The sensitivity of these daily calculations to fluctuations in temperatures, humidity, winds, and sky cover allows forecasters with knowledge of local terrain and weather patterns to better forecast in the ETrc inputs. The daily FRET product then evolved into a suite of products, including a weekly ETrc forecast for better water planning and a tabular point forecast for easy ingest into local water management-models. The ETrc forecast product suite allows water managers, the agricultural community, and the public to make more informed water-use decisions. These products permit operational planning, especially with the impending drought across much of the West. For example, the California Department of Water Resources not only ingests the FRET into their soil moisture models, but uses the FRET calculations when determining the reservoir releases in the Sacramento and American Rivers. We will also focus on the expansion of FRET verification, which compares the daily FRET to the observations of ETo from the California Irrigation Management Information System (CIMIS) across California's Central Valley for the 2012 water year.

  8. Dynamic Modeling of an Evapotranspiration Cap

    SciTech Connect

    Jacob J. Jacobson; Steven Piet; Rafael Soto; Gerald Sehlke; Harold Heydt; John Visser

    2005-10-01

    The U.S. Department of Energy is scheduled to design and install hundreds of landfill caps/barriers over the next several decades and these caps will have a design life expectancy of up to 1,000 years. Other landfill caps with 30 year design lifetimes are reaching the end of their original design life; the changes to these caps need to be understood to provide a basis for lifetime extension. Defining the attributes that make a successful cap (one that isolates the waste from the environment) is crucial to these efforts. Because cap systems such as landfill caps are dynamic in nature, it is impossible to understand, monitor, and update lifetime predictions without understanding the dynamics of cap degradation, which is most often due to multiple interdependent factors rather than isolated independent events. In an attempt to understand the dynamics of cap degradation, a computer model using system dynamics is being developed to capture the complex behavior of an evapotranspiration cap. The specific objectives of this project are to capture the dynamic, nonlinear feedback loop structures underlying an evapotranspiration cap and, through computer simulation, gain a better understanding of long-term behavior, influencing factors, and, ultimately, long-term cap performance.

  9. Hourly and daily evapotranspiration of alfalfa under regional advection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Regional advection often affects the evapotranspiration rates of irrigated crops in the Southern High Plains. In 1998, during a 10-day period (13-22 June) of unusually strong advection, high evapotranspiration (ET) rates for unstressed, irrigated alfalfa (Medicago sativa) were measured with two prec...

  10. Evapotranspiration information reporting: I. Factors governing measurement accuracy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More and more evapotranspiration (ET) models, ET crop coefficients, and associated measurements of ET are being reported in the literature and used to develop, calibrate, and test important ET process models. Evapotranspiration data are derived from a range of measurement systems including lysimeter...

  11. Prediction of the Reference Evapotranspiration Using a Chaotic Approach

    PubMed Central

    Wang, Wei-guang; Zou, Shan; Luo, Zhao-hui; Zhang, Wei; Kong, Jun

    2014-01-01

    Evapotranspiration is one of the most important hydrological variables in the context of water resources management. An attempt was made to understand and predict the dynamics of reference evapotranspiration from a nonlinear dynamical perspective in this study. The reference evapotranspiration data was calculated using the FAO Penman-Monteith equation with the observed daily meteorological data for the period 1966–2005 at four meteorological stations (i.e., Baotou, Zhangbei, Kaifeng, and Shaoguan) representing a wide range of climatic conditions of China. The correlation dimension method was employed to investigate the chaotic behavior of the reference evapotranspiration series. The existence of chaos in the reference evapotranspiration series at the four different locations was proved by the finite and low correlation dimension. A local approximation approach was employed to forecast the daily reference evapotranspiration series. Low root mean square error (RSME) and mean absolute error (MAE) (for all locations lower than 0.31 and 0.24, resp.), high correlation coefficient (CC), and modified coefficient of efficiency (for all locations larger than 0.97 and 0.8, resp.) indicate that the predicted reference evapotranspiration agrees well with the observed one. The encouraging results indicate the suitableness of chaotic approach for understanding and predicting the dynamics of the reference evapotranspiration. PMID:25133221

  12. Prediction of the reference evapotranspiration using a chaotic approach.

    PubMed

    Wang, Wei-guang; Zou, Shan; Luo, Zhao-hui; Zhang, Wei; Chen, Dan; Kong, Jun

    2014-01-01

    Evapotranspiration is one of the most important hydrological variables in the context of water resources management. An attempt was made to understand and predict the dynamics of reference evapotranspiration from a nonlinear dynamical perspective in this study. The reference evapotranspiration data was calculated using the FAO Penman-Monteith equation with the observed daily meteorological data for the period 1966-2005 at four meteorological stations (i.e., Baotou, Zhangbei, Kaifeng, and Shaoguan) representing a wide range of climatic conditions of China. The correlation dimension method was employed to investigate the chaotic behavior of the reference evapotranspiration series. The existence of chaos in the reference evapotranspiration series at the four different locations was proved by the finite and low correlation dimension. A local approximation approach was employed to forecast the daily reference evapotranspiration series. Low root mean square error (RSME) and mean absolute error (MAE) (for all locations lower than 0.31 and 0.24, resp.), high correlation coefficient (CC), and modified coefficient of efficiency (for all locations larger than 0.97 and 0.8, resp.) indicate that the predicted reference evapotranspiration agrees well with the observed one. The encouraging results indicate the suitableness of chaotic approach for understanding and predicting the dynamics of the reference evapotranspiration. PMID:25133221

  13. Evaluation of alternative methods for estimating reference evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration is an important component in water-balance and irrigation scheduling models. While the FAO-56 Penman-Monteith method has become the de facto standard for estimating reference evapotranspiration (ETo), it is a complex method requiring several weather parameters. Required weather ...

  14. Detection of the Compressed Primary Stellar Wind in eta Carinae

    NASA Technical Reports Server (NTRS)

    Teodoro, Mairan Macedo; Madura, Thomas I.; Gull, Theodore R.; Corcoran, Michael F.; Hamaguchi, K.

    2014-01-01

    A series of three HST/STIS spectroscopic mappings, spaced approximately one year apart, reveal three partial arcs in [Fe II] and [Ni II] emissions moving outward from eta Carinae. We identify these arcs with the shell-like structures, seen in the 3D hydrodynamical simulations, formed by compression of the primary wind by the secondary wind during periastron passages.

  15. Targeting Inaccurate Atomic Data in the Eta Car Ejecta Absorption

    NASA Technical Reports Server (NTRS)

    Nielsen, K. E.; Kober, G. Vieira; Gull, T. R.; Blackwell-Whitehead, R.; Nilsson, H.

    2006-01-01

    The input from the laboratory spectroscopist community has on many occasions helped the analysis of the eta Car spectrum. Our analysis has targeted spectra where improved wavelengths and oscillator strengths are needed. We will demonstrate how experimentally derived atomic data have improved our spectral analysis, and illuminate where more work still is needed.

  16. EMISSIONS PROCESSING FOR THE ETA/ CMAQ AIR QUALITY FORECAST SYSTEM

    EPA Science Inventory

    NOAA and EPA have created an Air Quality Forecast (AQF) system. This AQF system links an adaptation of the EPA's Community Multiscale Air Quality Model with the 12 kilometer ETA model running operationally at NOAA's National Center for Environmental Predication (NCEP). One of the...

  17. Eta Car's spectroscopic event begins to differ from 2009

    NASA Astrophysics Data System (ADS)

    Davidson, Kris; Mehner, Andrea; Humphreys, Roberta; Ishibash, K.; Martin, J. C.

    2014-08-01

    The middle of eta Car's 2014.6 spectroscopic event (periastron passage) occurred in mid-August (ATEL #6334, #6336, #6357, #6368, #6380). HST/STIS observations on July 13, July 30, and August 15 strongly suggest that the exotic He II 4687 emission is reappearing sooner than in the 2009.1 event.

  18. The Corrected Eta-Squared Coefficient: A Value Added Approach.

    ERIC Educational Resources Information Center

    Barnette, J. Jackson; McLean, James E.

    Eta-Squared (ES) is often used as a measure of strength of association of an effect, a measure often associated with effect size. It is also considered the proportion of total variance accounted for by an independent variable. It is simple to compute and interpret. However, it has one critical weakness cited by several authors (C. Huberty, 1994;…

  19. Spectra of Eta Carina from Objective Prism Photographic Plates

    NASA Astrophysics Data System (ADS)

    Cline, J. Donald; Castelaz, M.; Barker, T.

    2008-05-01

    Brightness and spectral variations of Eta Carina occur over a 5.5 year cycle. Emission lines were observed to fade in 1948, 1962, 1981, 1987, and 1992 (Damineli 1996, ApJ, 460, L49), and 1997 (Eta Carinae at the Millennium, ASP Conf. Ser. 179, ed. J.A. Morse, R.M. Humphreys, and A. Damineli). Gaps in the observation of spectra occur in 1970 and 1975 when two other such occurrences of the 5.5 year cycle were expected. Objective prism photographic plates of Eta Carina were found in the Astronomical Photographic Data Archive located at Pisgah Astronomical Research Institute. The plates belong to the University of Michigan survey (Houk 1978, Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars). One plate, IN emulsion + RG1 filter, was taken on 1968 July 4 UT. The other plate, IIaO emulsion, was taken on 1972 March 12 UT. These plates were taken between the 5.5 year cyclic events of 1970 and 1975 and therefore represent the usual emission line spectra. The spectrum of Eta Car was extracted from each of the objective prism plates and will be presented.

  20. Recent Results from HST/STIS Spectroscopy of eta Carinae

    NASA Astrophysics Data System (ADS)

    Davidson, K.; Gull, T. R.; Ishibashi, K.

    2001-06-01

    Repeated HST/STIS observations of eta Carinae and its ejecta have produced a large spectroscopic data set which is a unique resource for the astrophysics of massive stars, ejecta, and related topics. Here we report the existence of this data set and mention some implications concerning the star, spatially resolved from its bright diffuse ejecta.

  1. Eta Sigma Gamma: Preparing Leaders Today for Tomorrow's Challenges

    ERIC Educational Resources Information Center

    Brown, Kelli McCormack

    2007-01-01

    There is no one definition for a leader or for leadership, but most people can identify a leader and can provide qualities of a good leader or good leadership. The founders of Eta Gamma Gamma--William Bock, Warren Schaller, and Robert Synovitz--all displayed a critical characteristic of leadership by having and acting on a vision. Leadership has…

  2. Improving Evapotranspiration Estimates Using Multi-Platform Remote Sensing

    NASA Astrophysics Data System (ADS)

    Knipper, Kyle; Hogue, Terri; Franz, Kristie; Scott, Russell

    2016-04-01

    Understanding the linkages between energy and water cycles through evapotranspiration (ET) is uniquely challenging given its dependence on a range of climatological parameters and surface/atmospheric heterogeneity. A number of methods have been developed to estimate ET either from primarily remote-sensing observations, in-situ measurements, or a combination of the two. However, the scale of many of these methods may be too large to provide needed information about the spatial and temporal variability of ET that can occur over regions with acute or chronic land cover change and precipitation driven fluxes. The current study aims to improve the spatial and temporal variability of ET utilizing only satellite-based observations by incorporating a potential evapotranspiration (PET) methodology with satellite-based down-scaled soil moisture estimates in southern Arizona, USA. Initially, soil moisture estimates from AMSR2 and SMOS are downscaled to 1km through a triangular relationship between MODIS land surface temperature (MYD11A1), vegetation indices (MOD13Q1/MYD13Q1), and brightness temperature. Downscaled soil moisture values are then used to scale PET to actual ET (AET) at a daily, 1km resolution. Derived AET estimates are compared to observed flux tower estimates, the North American Land Data Assimilation System (NLDAS) model output (i.e. Variable Infiltration Capacity (VIC) Macroscale Hydrologic Model, Mosiac Model, and Noah Model simulations), the Operational Simplified Surface Energy Balance Model (SSEBop), and a calibrated empirical ET model created specifically for the region. Preliminary results indicate a strong increase in correlation when incorporating the downscaling technique to original AMSR2 and SMOS soil moisture values, with the added benefit of being able to decipher small scale heterogeneity in soil moisture (riparian versus desert grassland). AET results show strong correlations with relatively low error and bias when compared to flux tower

  3. Effects of spatial variability and scale on areal -average evapotranspiration

    NASA Technical Reports Server (NTRS)

    Famiglietti, J. S.; Wood, Eric F.

    1993-01-01

    This paper explores the effect of spatial variability and scale on areally-averaged evapotranspiration. A spatially-distributed water and energy balance model is employed to determine the effect of explicit patterns of model parameters and atmospheric forcing on modeled areally-averaged evapotranspiration over a range of increasing spatial scales. The analysis is performed from the local scale to the catchment scale. The study area is King's Creek catchment, an 11.7 sq km watershed located on the native tallgrass prairie of Kansas. The dominant controls on the scaling behavior of catchment-average evapotranspiration are investigated by simulation, as is the existence of a threshold scale for evapotranspiration modeling, with implications for explicit versus statistical representation of important process controls. It appears that some of our findings are fairly general, and will therefore provide a framework for understanding the scaling behavior of areally-averaged evapotranspiration at the catchment and larger scales.

  4. Basin Scale Estimates of Evapotranspiration Using GRACE and other Observations

    NASA Technical Reports Server (NTRS)

    Rodell, M.; Famiglietti, J. S.; Chen, J.; Seneviratne, S. I.; Viterbo, P.; Holl, S.; Wilson, C. R.

    2004-01-01

    Evapotranspiration is integral to studies of the Earth system, yet it is difficult to measure on regional scales. One estimation technique is a terrestrial water budget, i.e., total precipitation minus the sum of evapotranspiration and net runoff equals the change in water storage. Gravity Recovery and Climate Experiment (GRACE) satellite gravity observations are now enabling closure of this equation by providing the terrestrial water storage change. Equations are presented here for estimating evapotranspiration using observation based information, taking into account the unique nature of GRACE observations. GRACE water storage changes are first substantiated by comparing with results from a land surface model and a combined atmospheric-terrestrial water budget approach. Evapotranspiration is then estimated for 14 time periods over the Mississippi River basin and compared with output from three modeling systems. The GRACE estimates generally lay in the middle of the models and may provide skill in evaluating modeled evapotranspiration.

  5. The Eight-meter-wavelength Transient Array (ETA)

    NASA Astrophysics Data System (ADS)

    Simonetti, J. H.; Ellingson, S. W.; Patterson, C. D.; Taylor, W.; Venugopal, V.; Cutchin, S.; Boor, Z.

    2005-12-01

    The Eight-meter-wavelength Transient Array (ETA) is a radio telescope utilizing a low-cost backend, which implements flexible, reconfigurable computing techniques. It is designed to continuously monitor nearly the entire northern sky at 29-47MHz in a search for low-frequency radio transients (short pulses) from high-energy astrophysical phenomena. This antenna array, which is currently under construction, is located in a relatively radio-quiet area in the Blue Ridge Mountains southwest of Asheville, NC, at the Pisgah Astronomical Research Institute (PARI). The array consists of 12 dual-polarization dipole antennas. The core of the array is 10 antenna stations arranged in a 16-m diameter circle with one antenna station at the center. In addition, one antenna station is situated about 50m to the north of the core and another is about 50m to the east of the core. A 26-m dish on the PARI site (about 1km from the ETA core) will be used for follow-up, added aperture, longer baselines, and additional radio frequency interference (RFI) mitigation. Preliminary observations with one test antenna station have detected the expected Galactic emission in this frequency range; ETA will be Galactic-noise limited. The ETA backend will utilize off-the-shelf components and a cluster of Field Programmable Gate Arrays (FPGAs) for detecting pulses of various lengths, dispersion measures, and directions (synthesized delay beams), while incorporating various RFI countermeasures. Potential sources of radio transients that might be observed by ETA include gamma-ray bursts (prompt emission), supernovae (prompt emission), coalescing compact-object binaries (e.g., neutron star -- neutron star, neutron star -- black hole), and exploding primordial black holes. This array should detect giant pulses from the Crab Pulsar, and possibly other pulsars. ETA is a collaboration of the Electrical and Computer Engineering Department and Physics Department at Virginia Tech, and PARI. ETA work at Virginia

  6. Origin of the Central Constant Emission Component of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Hamaguchi, Kenji; Corocoran, M. F.; Gull, T.; Ishibashi, K.; Pittard, J. M.; Hillier, D. J.; Damineli, A.; Davidson, K.; Nielsen, K. E.; Owocki, S.; Henley, D.; Pollock, A.; Okazaki, A.

    2010-01-01

    The X-ray campaign observation of the wind-wind colliding (WWC) binary system, Eta Carinae, targeted at its periastron passage in 2003, presented a detailed view of the flux and spectral variations of the X-ray minimum phase. One of the discoveries in this campaign was a central constant emission (CCE) component very near the central WWC source (Hamaguchi et al. 2007, ApJ, 663, 522). The CCE component was noticed between 1-3 keY during the X-ray minima and showed no variation on either short timescales within any observation or long timescales of up to 10 years. Hamaguchi et al. (2007) discussed possible origins as collisionally heated shocks from the fast polar winds from Eta Car or the fast moving outflow from the WWC with the ambient gas, or shocked gas that is intrinsic to the wind of Eta Car. During the 2009 periastron passage, we launched another focussed observing campaign of Eta Carinae with the Chandra, XMM-Newton and Suzaku observatories, concentrating on the X-ray faintest phase named the deep X-ray minimum. Thanks to multiple observations during the deep X-ray minimum, we found that the CCE spectrum extended up to 10 keV, indicating presence of hot plasma of kT approx.4-6 keV. This result excludes two possible origins that assume relatively slow winds (v approx. 1000 km/s) and only leaves the possibility that the CCE plasma is wind blown bubble at the WWC downstream. The CCE spectrum in 2009 showed a factor of 2 higher soft band flux as the CCE spectrum in 2003, while the hard band flux was almost unchanged. This variation suggests decrease in absorption column along the line of sight. We compare this result with recent increase in V-band magnitude of Eta Carinae and discuss location of the CCE plasma.

  7. Scaled-up dual anode/cathode microbial fuel cell stack for actual ethanolamine wastewater treatment.

    PubMed

    An, Byung-Min; Heo, Yoon; Maitlo, Hubdar-Ali; Park, Joo-Yang

    2016-06-01

    The aim of this work was to develop the scale-up microbial fuel cell technology for actual ethanolamine wastewater treatment, dual anode/cathode MFC stacks connected in series to achieve any desired current, treatment capacity, and volume capacity. However, after feeding actual wastewater into the MFC, maximum power density decreased while the corresponding internal resistance increased. With continuous electricity production, a stack of eight MFCs in series achieved 96.05% of COD removal and 97.30% of ammonia removal at a flow rate of 15.98L/d (HRT 12h). The scaled-up dual anode/cathode MFC stack system in this research was demonstrated to treat actual ETA wastewater with the added benefit of harvesting electricity energy. PMID:26888335

  8. Daily lsa-saf evapotranspiration product

    NASA Astrophysics Data System (ADS)

    Arboleda Rodallega, Alirio; Ghilain, Nicolas; Meulenberghs, Francoise

    2010-05-01

    In the framework of the EUMETSAT's Satellite Application Facility on Land Surface Analysis (LSA-SAF), some models have been implemented in view to characterize continental surfaces by using information obtained from MSG and EPS satellites. In this context a method has been developed in order to monitor the flux of water (Evapotranspiration) between the land surface and the atmosphere. The method is based on a physical approach in which radiative data derived from Meteosat Second Generation (MSG) satellites together with land-cover information are used to constrain a physical model of energy exchange between the soil-vegetation system and the atmosphere. The implemented algorithm provides instantaneous ET estimates over four regions defined in the MSG FOV (the defined regions cover Europe, Africa and the west of south America), with MSG spatial resolution (3km at sub satellite point) and a temporal time step of 30 minutes. The scope of the method is limited to evaporation from terrestrial surfaces rather than from lakes or oceans. The instantaneous product has been validated over different vegetation cover and climatic conditions, providing evidence that the algorithm is able to reproduce ET estimates with accuracy equivalent to the accuracy of ET obtained from observations. In 2009 the instantaneous ET product has been declared pre-operational by EUMETSAT, allowing the product to be disseminated to a larger community of users (http://landsaf.meteo.pt). In some areas like agriculture, hydrology, water management, ecology and climate studies the main concern is not instantaneous but accumulated values over days, months or longer periods. To encompass the need for these community of users, a daily ET product in which daily evapotranspiration is obtained as temporal integration of instantaneous values has been developed. In this contribution we will present the methodology used to obtain instantaneous ET estimates and the procedure applied to derive daily

  9. Estimating evapotranspiration in natural and constructed wetlands

    USGS Publications Warehouse

    Lott, R. Brandon; Hunt, Randall J.

    2001-01-01

    Difficulties in accurately calculating evapotranspiration (ET) in wetlands can lead to inaccurate water balances—information important for many compensatory mitigation projects. Simple meteorological methods or off-site ET data often are used to estimate ET, but these approaches do not include potentially important site-specific factors such as plant community, root-zone water levels, and soil properties. The objective of this study was to compare a commonly used meterological estimate of potential evapotranspiration (PET) with direct measurements of ET (lysimeters and water-table fluctuations) and small-scale root-zone geochemistry in a natural and constructed wetland system. Unlike what has been commonly noted, the results of the study demonstrated that the commonly used Penman combination method of estimating PET underestimated the ET that was measured directly in the natural wetland over most of the growing season. This result is likely due to surface heterogeneity and related roughness efffects not included in the simple PET estimate. The meterological method more closely approximated season-long measured ET rates in the constructed wetland but may overestimate the ET rate late in the growing season. ET rates also were temporally variable in wetlands over a range of time scales because they can be influenced by the relation of the water table to the root zone and the timing of plant senescence. Small-scale geochemical sampling of the shallow root zone was able to provide an independent evaluation of ET rates, supporting the identification of higher ET rates in the natural wetlands and differences in temporal ET rates due to the timing of senescence. These discrepancies illustrate potential problems with extrapolating off-site estimates of ET or single measurements of ET from a site over space or time.

  10. Water Footprint of a Super-intensive Olive Grove Under Mediterranean Climate using Ground-based Evapotranspiration Measurements and Remote Sensing

    NASA Astrophysics Data System (ADS)

    Nogueira, A. M.; Paço, T. A.; Silvestre, J. C.; Gonzalez, L. F.; Santos, F. L.; Pereira, L. S.

    2012-04-01

    measurements were used to calculate water footprint instead of the common procedure (using evapotranspiration estimates), this might have also introduced some differences. The potential of using remote sensing techniques for the assessment of water footprint of crops has been discussed in recent literature. It can provide estimates of actual evapotranspiration, of precipitation, of surface runoff and of irrigation needs when associated with modelling. In this study we further compare the water footprint estimates using in situ evapotranspiration measurements and water footprint estimates using remote sensing techniques. A comparison with the irrigation records for this particular olive orchard will be used to validate the approaches.

  11. Evapotranspiration studies for protective barriers: FY 1988 status report

    SciTech Connect

    Link, S.O.; Thiede, M.E.; Evans, R.D.; Downs, J.L.; Waugh, W.J.

    1990-05-01

    In FY 1988, evapotranspiration studies in support of the Protective Barrier Development Program focused on developing instruments to measure evapotranspiration and on conducting natural analog studies. This report describes a has exchange chamber being developed that will control internal temperature and relative humidity to simulate outdoor conditions. This device will measure evapotranspiration rates unambiguously from any surface and measure carbon dioxide exchange rates, which will provide information on plant growth processes. The report also describes ecophysiological experiments that were conducted to determine water and carbon dynamics of shrubs. 5 refs., 24 figs.

  12. Assessment of actual transpiration rate in olive tree field combining sap-flow, leaf area index and scintillometer measurements

    NASA Astrophysics Data System (ADS)

    Agnese, C.; Cammalleri, C.; Ciraolo, G.; Minacapilli, M.; Provenzano, G.; Rallo, G.; de Bruin, H. A. R.

    2009-09-01

    Models to estimate the actual evapotranspiration (ET) in sparse vegetation area can be fundamental for agricultural water managements, especially when water availability is a limiting factor. Models validation must be carried out by considering in situ measurements referred to the field scale, which is the relevant scale of the modelled variables. Moreover, a particular relevance assumes to consider separately the components of plant transpiration (T) and soil evaporation (E), because only the first is actually related to the crop stress conditions. Objective of the paper was to assess a procedure aimed to estimate olive trees actual transpiration by combining sap flow measurements with the scintillometer technique at field scale. The study area, located in Western Sicily (Italy), is mainly cultivated with olive crop and is characterized by typical Mediterranean semi-arid climate. Measurements of sap flow and crop actual evapotranspiration rate were carried out during 2008 irrigation season. Crop transpiration fluxes, measured on some plants by means of sap flow sensors, were upscaled considering the leaf area index (LAI). The comparison between evapotranspiration values, derived by displaced-beam small-aperture scintillometer (DBSAS-SLS20, Scintec AG), with the transpiration fluxes obtained by the sap flow sensors, also allowed to evaluate the contribute of soil evaporation in an area characterized by low vegetation coverage.

  13. Linguistic Theory and Actual Language.

    ERIC Educational Resources Information Center

    Segerdahl, Par

    1995-01-01

    Examines Noam Chomsky's (1957) discussion of "grammaticalness" and the role of linguistics in the "correct" way of speaking and writing. It is argued that the concern of linguistics with the tools of grammar has resulted in confusion, with the tools becoming mixed up with the actual language, thereby becoming the central element in a metaphysical…

  14. Spatially distributed evapotranspiration and recharge estimation for sand regions of Hungary in the context of climate change

    NASA Astrophysics Data System (ADS)

    Csáki, Péter; Kalicz, Péter; Gribovszki, Zoltán

    2016-04-01

    Water balance of sand regions of Hungary was analysed using remote-sensing based evapotranspiration (ET) maps (1*1 km spatial resolution) by CREMAP model over the 2000-2008 period. The mean annual (2000-2008) net groundwater recharge (R) estimated as the difference in mean annual precipitation (P) and ET, taking advantage that for sand regions the surface runoff is commonly negligible. For the examined nine-year period (2000-2008) the ET and R were about 90 percent and 10 percent of the P. The mean annual ET and R were analysed in the context of land cover types. A Budyko-model was used in spatially-distributed mode for the climate change impact analysis. The parameters of the Budyko-model (α) was calculated for pixels without surplus water. For the extra-water affected pixels a linear model with β-parameters (actual evapotranspiration / pan-evapotranspiration) was used. These parameter maps can be used for evaluating future ET and R in spatially-distributed mode (1*1 km resolution). By using the two parameter maps (α and β) and data of regional climate models (mean annual temperature and precipitation) evapotranspiration and net groundwater recharge projections have been done for three future periods (2011-2040, 2041-2070, 2071-2100). The expected ET and R changes have been determined relative to a reference period (1981-2010). According to the projections, by the end of the 21th century, ET may increase while in case of R a heavy decrease can be detected for the sand regions of Hungary. This research has been supported by Agroclimate.2 VKSZ_12-1-2013-0034 project. Keywords: evapotranspiration, net groundwater recharge, climate change, Budyko-model

  15. The application of a Hybrid Evapotranspiration approach in rainfed wheat

    NASA Astrophysics Data System (ADS)

    Geli, Hatim; González-Piqueras, Jose; Torrres, Enrique; Campos, Isidro; Neale, Christopher; Calera, Alfonso

    2013-04-01

    The spatio-temporal estimates of evapotranspiration (ET) have been traditionally addressed applying the water balance (WB) model of the root zone using the FAO-56 approach. The WB model is a prognostic approach of obtaining estimates of the ET and soil moisture on a daily basis. The reflectance based basal-crop coefficient Ksbrf in the WB model is determined from remote sensing data instead of the tabulated averaged basal crop coefficients (Kcb). This improvement over tabulated Kc describes the actual temporal and spatial variability and the growing conditions pattern within the field. Maps of spatially distributed actual ET are obtained applying a two source energy balance (TSEB) Model of Norman et al. (1995), which provides instantaneous estimates of surface energy fluxes including the latent heat flux that can be extrapolated to daily estimates of ET. The soil moisture (SM) plays a key-role in understanding the spatial and temporal variability for improved estimates of both SM and ET. A multiple layer model simulating the dynamics in the soil profile has been used in order to better describe the SM status obtained using the FAO-56 model that considers a single value in the root zone. The SM content is very important in semiarid areas where the crops can develop their roots under water stress environments. Estimates of ET from the TSEB and WB models are independent and can be combined using data assimilation techniques. This hybrid ET approach as described by Geli (2012) and Neale et al. (2012) provides improved estimates of both ET and SM of the root zone and was also applied to irrigated and non-irrigated cotton grown under highly convective conditions. In this work the hybrid ET approach is applied to a rainfed wheat area of 18 ha in extension in La Mancha, Spain (39° 17´N, 1° 59'W, 700 m amsl) during the growing season of 2006. The area has a Mediterranean climate, considered semi-arid with scarce rain with a total of 122 mm measured throughout the growing

  16. Observation of B0-->omega K0, B+-->eta pi+, and B+-->eta K+ and study of related decays.

    PubMed

    Aubert, B; Barate, R; Boutigny, D; Couderc, F; Gaillard, J-M; Hicheur, A; Karyotakis, Y; Lees, J P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; LeClerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Morgan, S E; Watson, A T; Watson, N K; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmuecker, H; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Mackay, C; Wilson, F F; Abe, K; Cuhadar-Donszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; McKemey, A K; Teodorescu, L; Blinov, V E; Bukin, A D; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Gary, J W; Layter, J; Shen, B C; Wang, K; del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, Sh; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Beringer, J; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Spradlin, P; Walkowiak, W; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Erwin, R J; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Lee, C L; Nauenberg, U; Olivas, A; Rankin, P; Roy, J; Smith, J G; van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Soffer, A; Toki, W H; Wilson, R J; Zhang, J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Schubert, J; Schubert, K R; Schwierz, R; Spaan, B; Bernard, D; Bonneaud, G R; Brochard, F; Grenier, P; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Bard, D J; Khan, A; Lavin, D; Muheim, F; Playfer, S; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Patteri, P; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Taylor, G P; Grenier, G J; Lee, S-J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Brigljević, V; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, E; Gamet, R; Kay, M; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Harrison, P F; Mohanty, G B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; George, S; Green, M G; Kurup, A; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Lafferty, G D; Lyon, A J; Williams, J C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Cote-Ahern, D; Taras, P; Nicholson, H; Cartaro, C; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; Wilden, L; Jessop, C P; LoSecco, J M; Gabriel, T A; Allmendinger, T; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Ter-Antonyan, R; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; de la Vaissière, Ch; Del Buono, L; Hamon, O; John, M J J; Leruste, Ph; Ocariz, J; Pivk, M; Roos, L; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Anulli, F; Biasini, M; Peruzzi, I M; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Del Gamba, V; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martinez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lu, C; Miftakov, V; Olsen, J; Smith, A J S; Varnes, E W; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Safai Tehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Geddes, N I; Gopal, G P; Olaiya, E O; Xella, S M; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P-F; Hamel de Monchenault, G; Kozanecki, W; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yeche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Convery, M R; Cristinziani, M; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Elsen, E E; Field, R C; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Va'vra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wright, D H; Young, C C; Burchat, P R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihalyi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; von Wimmersperg-Toeller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H

    2004-02-13

    We present measurements of branching fractions and charge asymmetries for seven B-meson decays with an eta, eta', or omega meson in the final state. The data sample corresponds to 89x10(6) BB pairs produced from e(+)e(-) annihilation at the Upsilon(4S) resonance. We measure the following branching fractions in units of 10(-6): B(B+-->eta pi(+))=5.3+/-1.0+/-0.3, B(B+-->eta K+)=3.4+/-0.8+/-0.2, B(B0-->eta K0)=2.9+/-1.0+/-0.2 (<5.2, 90% C.L.), B(B+-->eta(')pi(+))=2.7+/-1.2+/-0.3 (<4.5, 90% C.L.), B(B+-->omega pi(+))=5.5+/-0.9+/-0.5, B(B+-->omega K+)=4.8+/-0.8+/-0.4, and B(B0-->omega K0)=5.9(+1.6)(-1.3)+/-0.5. The charge asymmetries are A(ch)(B+-->eta pi(+))=-0.44+/-0.18+/-0.01, A(ch)(B+-->eta K+)=-0.52+/-0.24+/-0.01, A(ch)(B+-->omega pi(+))=0.03+/-0.16+/-0.01, and A(ch)(B+-->omega K+)=-0.09+/-0.17+/-0.01. PMID:14995230

  17. Evapotranspiration Parameterizations at a Grass Site in Florida, USA

    NASA Astrophysics Data System (ADS)

    Rizou, M.; Sumner, D. M.; Nnadi, F.

    2007-05-01

    In spite of the fact that grasslands account for about 40% of the ice-free global terrestrial land cover, their contribution to the surface exchanges of energy and water in local and regional scale is so far uncertain. In this study, the sensitivity of evapotranspiration (ET) and other energy fluxes to wetness variables, namely the volumetric Soil Water Content (SWC) and Antecedent Precipitation Index (API), over a non-irrigated grass site in Central Florida, USA (28.049 N, 81.400 W) were investigated. Eddy correlation and soil water content measurements were taken by USGS (U.S. Geological Survey) at the grass study site, within 100 m of a SFWMD (South Florida Water Management District) weather station. The soil is composed of fine sands and it is mainly covered by Paspalum notatum (bahia grass). Variable soil wetness conditions with API bounds of about 2 to 160 mm and water table levels of 0.03 to 1.22 m below ground surface, respectively, were observed throughout the year 2004. The Bowen ratio exhibited an average of 1 and values larger than 2 during few dry days. The daytime average ET was classified into two stages, first stage (energy-limited) and second stage (water- limited) based on the water availability. The critical values of API and SWC were found to be about 56 mm and 0.17 respectively, with the second one being approximately 33% of the SWC at saturation. The ET values estimated by the simple Priestley-Taylor (PT) method were compared to the actual values. The PT coefficient varied from a low bound of approximately 0.4 to a peak of 1.21. Simple relationships for the PT empirical factor were employed in terms of SWC and API to improve the accuracy of the second stage observations. The results of the ET parameterizations closely match eddy-covariance flux values on daily and longer time steps.

  18. Evapotranspiration parameterizations at a grass site in Florida, USA

    USGS Publications Warehouse

    Rizou, M.; Sumner, David M.; Nnadi, F.

    2007-01-01

    In spite of the fact that grasslands account for about 40% of the ice-free global terrestrial land cover, their contribution to the surface exchanges of energy and water in local and regional scale is so far uncertain. In this study, the sensitivity of evapotranspiration (ET) and other energy fluxes to wetness variables, namely the volumetric Soil Water Content (SWC) and Antecedent Precipitation Index (API), over a non-irrigated grass site in Central Florida, USA (28.049 N, 81.400 W) were investigated. Eddy correlation and soil water content measurements were taken by USGS (U.S. Geological Survey) at the grass study site, within 100 m of a SFWMD (South Florida Water Management District) weather station. The soil is composed of fine sands and it is mainly covered by Paspalum notatum (bahia grass). Variable soil wetness conditions with API bounds of about 2 to 160 mm and water table levels of 0.03 to 1.22 m below ground surface, respectively, were observed throughout the year 2004. The Bowen ratio exhibited an average of 1 and values larger than 2 during few dry days. The daytime average ET was classified into two stages, first stage (energy-limited) and second stage (water- limited) based on the water availability. The critical values of API and SWC were found to be about 56 mm and 0.17 respectively, with the second one being approximately 33% of the SWC at saturation. The ET values estimated by the simple Priestley-Taylor (PT) method were compared to the actual values. The PT coefficient varied from a low bound of approximately 0.4 to a peak of 1.21. Simple relationships for the PT empirical factor were employed in terms of SWC and API to improve the accuracy of the second stage observations. The results of the ET parameterizations closely match eddy-covariance flux values on daily and longer time steps.

  19. Divergence of reference evapotranspiration observations with windy tropical conditions

    NASA Astrophysics Data System (ADS)

    Anderson, R. G.; Wang, D.; Tirado-Corbalá, R.; Zhang, H.; Ayars, J. E.

    2014-06-01

    Standardized reference evapotranspiration (ET) and ecosystem-specific vegetation coefficients are frequently used to estimate actual ET. However, equations for calculating reference ET have not been well validated in tropical environments. We measured ET (ETEC) using Eddy Covariance (EC) towers at two irrigated sugarcane fields on the leeward (dry) side of Maui, Hawaii, USA in contrasting climates. We calculated reference ET at the fields using the short (ET0) and tall (ETr) vegetation versions of the American Society for Civil Engineers (ASCE) equation. The ASCE equations were compared to the Priestley-Taylor ET (ETPT) and ETEC. Reference ET from the ASCE approaches exceeded ETEC during the mid-period (when vegetation coefficients suggest ETEC should exceed reference ET). At the windier tower site, cumulative ETr exceeded ETEC by 854 mm over the course of the mid-period (267 days). At the less windy site, mid-period ETr still exceeded ETEC, but the difference was smaller (443 mm). At both sites, ETPT approximated mid-period ETEC more closely than the ASCE equations ((ETPT-ETEC) < 170 mm). Analysis of applied water and precipitation, soil moisture, leaf stomatal resistance, and canopy cover suggest that the lower observed ETEC was not the result of water stress or reduced vegetation cover. Use of a custom calibrated bulk canopy resistance improved the reference ET estimate and reduced seasonal ET discrepancy relative to ETPT and ETEC for the less windy field and had mixed performance at the windier field. These divergences suggest that modifications to reference ET equations may be warranted in some tropical regions.

  20. Turbidity of a Binary Fluid Mixture: Determining Eta

    NASA Technical Reports Server (NTRS)

    Jacobs, Donald T.

    1996-01-01

    A ground based (1-g) experiment is in progress that will measure the turbidity of a density-matched, binary fluid mixture extremely close to its liquid-liquid critical point. By covering the range of reduced temperatures t equivalent to (T-T(sub c)) / T(sub c) from 10(exp -8) to 10(exp -2), the turbidity measurements will allow the critical exponent eta to be determined. No experiment has precisely determined a value of the critical exponent eta, yet its value is significant to theorists in critical phenomena. Relatively simple critical phenomena, as in the liquid-liquid system studied here, serve as model systems for more complex systems near a critical point.

  1. Turbidity of a binary fluid mixture: Determining eta

    NASA Technical Reports Server (NTRS)

    Jacobs, Donald T.

    1994-01-01

    A ground based (1-g) experiment is in progress that will measure the turbidity of a density-matched, binary fluid mixture extremely close to the critical point. By covering the range of reduced temperatures t is equivalent to (T-T(sub c))/T(sub c) from 10(exp -8) to 10(exp -2), the turbidity measurements will allow the critical exponent eta to be determined. No experiment has determined a value of the critical exponent eta, yet its value is significant to theorists in critical phenomena. Interpreting the turbidity correctly is important if future NASA flight experiments use turbidity as an indirect measurement of relative temperature in shuttle experiments on critical phenomena in fluids.

  2. A closer look at eta Carinae's surprising nitrogen chemistry

    NASA Astrophysics Data System (ADS)

    Cordiner, Martin; Jones, Paul; Millar, Tom; Charnley, Steven; Mcelroy, Daniel; Milam, Stefanie

    2013-04-01

    The ejecta of the luminous blue variable (LBV) star eta Carinae has recently been found to be surprisingly rich in simple nitrogen-bearing molecules, and theory predicts that more complex species such as HC3N and CH3CN are abundant in the warm inner regions of the Homunculus. We therefore propose to search for emission from HC3N, CH3CN and other nitrogen-bearing molecules in eta Carinae. We will also map HCN and HNC with unprecedented spatial detail to determine the origin and spatial extent of these species. The proposed observations will be crucial for developing chemical models of this source, which we will use to (1) promote understanding of the chemistry of this star and its mysterious ejecta and (2) provide information on molecule formation around massive stars that are about to undergo Type II supernova explosions.

  3. DETECTION OF THE COMPRESSED PRIMARY STELLAR WIND IN {eta} CARINAE

    SciTech Connect

    Teodoro, M.; Madura, T. I.; Gull, T. R.; Corcoran, M. F.; Hamaguchi, K.

    2013-08-10

    A series of three Hubble Space Telescope/Space Telescope Imaging Spectrograph spectroscopic mappings, spaced approximately one year apart, reveal three partial arcs in [Fe II] and [Ni II] emissions moving outward from {eta} Carinae. We identify these arcs with the shell-like structures, seen in the three-dimensional hydrodynamical simulations, formed by compression of the primary wind by the secondary wind during periastron passages.

  4. The eta Carinae Treasury Project and the HST/STIS

    NASA Technical Reports Server (NTRS)

    Martin, John C.; Davidson, Kris

    2006-01-01

    The HST Eta Carinae Treasury Project made extensive use of the HST/STIS from 1998 to the time of its failure in 2004. As one of the most prolific users of that instrument, the Treasury Project used the cross-dispersed spatial resolution of the STIS as few projects did. We present several enhancements to the existing STIS data reduction methods that are applicable to non-Treasury Project data in the STIS archive.

  5. Chandra X-Ray Observatory Image of Eta Carinae

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This Chandra X-Ray Observatory image of the mysterious superstar Eta Carinae reveals a surprising hot irner core, creating more questions than answers for astronomers. The image shows three distinct structures: An outer, horseshoe shaped ring about 2 light-years in diameter, a hot inner core about 3 light-months in diameter, and a hot central source less than a light-month in diameter which may contain the superstar. In 1 month, light travels a distance of approximately 489 billion miles (about 788 billion kilometers). All three structures are thought to represent shock waves produced by matter rushing away from the superstar at supersonic speeds. The temperature of the shock-heated gas ranges from 60 million degrees Kelvin in the central regions to 7 million degrees Kelvin on the outer structure. Eta Carinae is one of the most enigmatic and intriguing objects in our galaxy. Between 1837 and 1856, it increased dramatically in brightness to become the most prominent star in the sky except for Sirius, even through it is 7,500 light-years away, more than 80 times the distance to Sirius. This 'Great Eruption,' as it is called, had an energy comparable to a supernova, yet did not destroy the star, which faded to become a dim star, invisible to the naked eye. Since 1940, Eta Carinae has begun to brighten again, becoming visible to the naked eye. Photo credit: NASA/CXC/SAO

  6. High Velocity Absorption during Eta Car B's Periastron Passage

    NASA Technical Reports Server (NTRS)

    Nielsen, Krister E.; Groh, J. H.; Hillier, J.; Gull, Theodore R.; Owocki, S. P.; Okazaki, A. T.; Damineli, A.; Teodoro, M.; Weigelt, G.; Hartman, H.

    2010-01-01

    Eta Car is one of the most luminous massive stars in the Galaxy, with repeated eruptions with a 5.5 year periodicity. These events are caused by the periastron passage of a massive companion in an eccentric orbit. We report the VLT/CRIRES detection of a strong high-velocity, (<1900 km/s) , broad absorption wing in He I at 10833 A during the 2009.0 periastron passage. Previous observations during the 2003.5 event have shown evidence of such high-velocity absorption in the He I 10833 transition, allowing us to conclude that the high-velocity gas is crossing the line-of-sight toward Eta Car over a time period of approximately 2 months. Our analysis of HST/STlS archival data with observations of high velocity absorption in the ultraviolet Si IV and C IV resonance lines, confirm the presence of a high-velocity material during the spectroscopic low state. The observations provide direct detection of high-velocity material flowing from the wind-wind collision zone around the binary system, and we discuss the implications of the presence of high-velocity gas in Eta Car during periastron

  7. Fresh Clues in Eta Carinae's 2009.0 Event

    NASA Astrophysics Data System (ADS)

    Davidson, Kris; Martin, J. C.; Humphreys, R. M.; Mehner, A.; Ishibashi, K.; Ferland, G.; Hamann, F.

    2009-05-01

    Eta Carinae's most recent spectroscopic event climaxed in January 2009 and revealed significant new information. We obtained UV images with the HST/WFPC2, and violet-to-red spectroscopy with GMOS on the Gemini South telescope. The new NICI instrument on Gemini South obtained a remarkable set of near-IR images shortly after the peak of the event. Improved temporal coverage proves to be critical. With both HST/WFPC2 and Gemini/GMOS, the time intervals between observations were substantially smaller than we had achieved with HST/STIS and HST/ACS during the preceding event in mid-2003. Thus we find, for example, that the UV brightness of the central wind changed much faster than previous data could show or even hint. Meanwhile the behavior of the strange He II 4686 emission is greatly clarified, and a number of other features differed from the 2003 event. Regarding pre-event developments, Gemini/GMOS spectroscopy in 2007--2008 can be used to derive fresh constraints on the orbit of eta Car's hypothetical hot companion star. The high-spatial-resolution near-IR images obtained with Gemini/NICI show a dramatic new view of eta Car's Homunculus ejecta-nebula. Because of lesser extinction, these show deeper structure than the familiar HST images; some of the most conspicuous large near-IR structures have no UV-to-red counterparts. This program is partially funded by grants from STScI.

  8. Future directions in searching for eta-mesic nuclei

    NASA Astrophysics Data System (ADS)

    Haider, Quamrul; Liu, Lon-Chang

    2016-03-01

    Future directions in searching for eta-mesic nuclei: Q. Haider, Department of Physics and Engineering Physics, Fordham University, Bronx, N.Y. 10458, U.S.A. and L.C. Liu, Theoretical Division, Los Alamos National Laboratory, Los Alamos, N.M 87545, U.S.A. Eta-mesic nucleus or the quasibound nuclear state of an eta (η) meson in a nucleus is caused by strong-interaction force alone. This new type of nuclear species, which extends the landscape of nuclear physics, has been extensively studied since its prediction in 1986. In experimental search for η-mesic nucleus, transfer reactions have been frequently employed. One such reaction has led to the observation of the η-mesic nucleus 25Mg η . However, searching quasibound η-nucleus states in lighter nuclei such as 3He, 4He, and 11B has not yet yielded positive results. Searching η-mesic nuclei in medium-mass nuclear systems other than 25Mg is highly valuable. In view of the aforementioned experimental results, we suggest searching for more η-mesic nuclei in target nuclei having a mass number A >= 12 . Bronx, N.Y. 10458.

  9. Educational Software for Illustration of Drainage, Evapotranspiration, and Crop Yield.

    ERIC Educational Resources Information Center

    Khan, A. H.; And Others

    1996-01-01

    Describes a study that developed a software package for illustrating drainage, evapotranspiration, and crop yield as influenced by water conditions. The software is a tool for depicting water's influence on crop production in western Kansas. (DDR)

  10. Simulation of crop evapotranspiration and crop coefficient in weighing lysimeters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate quantification of crop evapotranspiration (ET) is critical in optimizing irrigation water productivity, especially, in the semiarid regions of the world where limited rainfall is supplemented by irrigation for profitable crop production. In this context, cropping system models are potential...

  11. Evapotranspiration-based irrigation scheduling of lettuce and broccoli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimation of crop evapotranspiration supports efficient irrigation water management, which in turn supports water conservation, mitigation of groundwater depletion/degradation, energy savings, and crop quality maintenance. Past research in California has revealed strong relationships between fract...

  12. Value of using remotely sensed evapotranspiration for SWAT model calibration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrologic models are useful management tools for assessing water resources solutions and estimating the potential impact of climate variation scenarios. A comprehensive understanding of the water budget components and especially the evapotranspiration (ET) is critical and often overlooked for adeq...

  13. Radiometric surface temperature calibration effects on satellite based evapotranspiration estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agriculture on the Texas High Plains (THP) uses approximately 89% of groundwater withdrawals from the Ogallala Aquifer, leading to steady decline in water table levels. Therefore, efficient water management is essential for sustaining agricultural production in the THP. Accurate evapotranspiration (...

  14. Potential Evapotranspiration Trends over South America

    NASA Astrophysics Data System (ADS)

    Maske, B. B.; Goncalves, L.

    2013-05-01

    Evapotranspiration (ET) is a key variable for energy and mass flux estimation from the land surface, and consequent water balance over regional to global scales. It also affects the atmosphere dynamics from weather to climate scales due to its link between the hydrological and energy cycles. Many studies investigating global ET trends have found a consistently positive signal in the period between 1982-1997 followed by a decline until 2008, which proved consistent with the acceleration of the hydrological cycle, caused by the global increase of temperature and radiative forcing. The large El nino in 1998, for instance, resulted in a negative trend of ET due in part to the limitation of soil moisture availability. However some researchers emphasize the importance of treating ET trends regionally and thus already found two distinct scenarios with inclusion of the regional dimension of evapotranspiration drivers for global studies: one where ET decreases following decreasing in pan evaporation in regions with ample supply of water and, the other scenario with a positive trend in observed ET following decreasing in pan evaporation, with indication of the latter being induced only by the tendency of precipitation. Studies about ET trend in the western United States, using data from the hydrologic model Variable Infiltration Capacity (VIC), also found significant seasonal variations associated with changes of temperature, snow accumulation and melting. Moreover, Canada researchers indicate strong correlation between ET variations and temperature, although temperature alone can not be related to changes of ET, since it not considers the heat flux in soil and cycles of freezing and melting of snow. Considering the importance of understanding variations of ET regionally, this study aims to analyze ET trends over South America. The data used are potential evapotranspiration estimated by the Penman-Monteith method, computed using data from meteorological stations for the

  15. The hysteretic evapotranspiration - vapor pressure deficit relation

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Manzoni, S.; Katul, G. G.; Porporato, A. M.; Yang, D.

    2013-12-01

    Diurnal hysteresis between evapotranspiration (ET) and vapor pressure deficit (VPD) was reported in many ecosystems but justification for its onset and magnitude remain incomplete with biotic and abiotic factors invoked as possible explanations. To place these explanations within a mathematical framework, ';rate-dependent' hysteresis originating from a phase angle difference between periodic input and output time series is first considered. Lysimeter evaporation (E) measurements from wet bare soils and model calculations using the Penman equation demonstrate that the E-VPD hysteresis emerges without any biotic effects due to a phase angle difference (or time lag) between net radiation the main driver of E, and VPD. Modulations originating from biotic effects on the ET-VPD hysteresis were then considered. The phase angle difference representation earlier employed was mathematically transformed into a storage problem and applied to the soil-plant system. The transformed system shows that soil moisture storage within the root zone can produce an ET-VPD hysteresis prototypical of those generated by phase-angle differences. To explore the interplay between all the lags in the soil-plant-atmosphere system and phase angle differences among forcing and response variables, a detailed soil-plant-atmosphere continuum (SPAC) model was developed and applied to a grassland ecosystem. The results of the SPAC model suggest that the hysteresis magnitude depends on the radiation-VPD lag. The soil moisture dry-down simulations also suggest that modeled root water potential and leaf water potential are both better indicators of the hysteresis magnitude than soil moisture, suggesting that plant water status is the main factor regulating the hysteretic relation between ET and VPD. Hence, the genesis and magnitude of the ET-VPD hysteresis are controlled directly by both biotic factors and abiotic factors such as time lag between radiation and VPD originating from boundary layer processes

  16. Eta Carinae: An Astrophysical Laboratory to Study Conditions During the Transition Between a Pseudo-Supernova and a Supernova

    NASA Astrophysics Data System (ADS)

    McKinnon, Darren; Gull, T. R.; Madura, T.

    2014-01-01

    A major puzzle in the studies of supernovae is the pseudo-supernova, or the near-supernovae state. It has been found to precede, in timespans ranging from months to years, a number of recently-detected distant supernovae. One explanation of these systems is that a member of a massive binary underwent a near-supernova event shortly before the actual supernova phenomenon. Luckily, we have a nearby massive binary, Eta Carinae, that provides an astrophysical laboratory of a near-analog. The massive, highly-eccentric, colliding-wind binary star system survived a non-terminal stellar explosion in the 1800's, leaving behind the incredible bipolar, 10"x20" Homunculus nebula. Today, the interaction of the binary stellar winds 1") is resolvable by the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). Using HST/STIS, several three-dimensional (3D) data cubes (2D spatial, 1D velocity) have been obtained at selected phases during Eta Carinae's 5.54-year orbital cycle. The data cubes were collected by mapping the central 1-2" at 0.05" intervals with a 52"x0.1" aperture. Selected forbidden lines, that form in the colliding wind regions, provide information on electron density of the shocked regions, the ionization by the hot secondary companion of the primary wind and how these regions change with orbital phase. By applying various analysis techniques to these data cubes, we can compare and measure temporal changes due to the interactions between the two massive winds. The observations, when compared to current 3D hydrodynamic models, provide insight on Eta Carinae's recent mass-loss history, important for determining the current and future states of this likely nearby supernova progenitor.

  17. Evapotranspiration and runoff in a forest watershed, western Japan

    NASA Astrophysics Data System (ADS)

    Shimizu, A.; Shimizu, T.; Miyabuchi, Y.; Ogawa, Y.

    2003-10-01

    Both water and heat balances were studied in a conifer plantation watershed in south-west Japan, within the warm-temperate East Asia monsoon area. Forest cover in the watershed consists mainly of Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa) plantations. Precipitation and runoff have been observed since 1991, so evapotranspiration can be compared with the water balance. Two meteorological observation towers were built to monitor evapotranspiration in the watershed. The annual average precipitation, amount of runoff and losses were 2166, 1243 and 923 mm, respectively. The evapotranspiration (latent heat flux) agreed well with the water balance losses. The average annual evapotranspiration at the tower built in the centre of the watershed was 902 mm; evapotranspiration at the other tower, further upslope, was 875 mm. The observed evapotranspiration was 39% to 40% of the average precipitation (2166 mm). The mean net radiation was c. 2·6 GJ m-2 year-1, and is considered a representative value of the net radiation (Rn) in coniferous plantations in this region. This region is classified in the humid zone based on the ratio of net radiation (Rn) to the energy required to evaporate the rainfall (R). The mean annual evaporation of canopy-intercepted water was 356 mm or about 15% of the average precipitation. Copyright

  18. Comparison of Crop Evapotranspiration Estimates from Reference Evapotranspiration Equations and a Variational Data Assimilation Approach

    NASA Astrophysics Data System (ADS)

    Bateni, S. M.; Michalik, T.; Multsch, S.; Breuer, L.

    2015-12-01

    Crop evapotranspiration (ETc) is a key component of water resources management in irrigation of farmlands as it determines the crop water consumption. Numerous methods have been used to estimate ETc for scheduling irrigation and evaluating the soil water balance. However, there is a significant difference in ETc estimates from various models, which leads to a large uncertainty in the soil water balance, crop water consumption, and irrigation scheduling. In this study, several commonly-used ETc equations (Turc, Priestley-Taylor, Hargreaves-Samani, Penman-Monteith) are compared with the variational data assimilation approach (VDA) of Bateni et al. (2013). The ETc equations initially estimate the reference evapotranspiration (ETo), which is the evapotranspiration from a healthy and actively-transpiring grass field with ample water in the soil. Thereafter, ETc is calculated by multiplying ETo by the crop coefficient (Kc), which accounts for the crop type and soil water stress. To properly apply the Kc to non-standard conditions, a daily water balance estimation for the root zone is required, which is done by two soil water budget models (Cropwat, Hydrus-1D) that compute incoming and outgoing water flows in the soil profile. In contrast to these methods that estimate ETc in two steps, the VDA approach directly predicts ETc by assimilating sequences of land surface temperature into the heat diffusion equation and thus it is expected to provide more accurate ETc estimates. All approaches are applied over three cropland sites namely, Bondville, Fermi, and Mead in the summer of 2006 and 2007. These sites are part of the AmeriFlux network and provide a wide variety of hydrological conditions. The results show that the variational data assimilation approach performs better compared to other equations.

  19. 2{eta} or not 2{eta}? Insights into the Cu CVD process using a Cu(I) precursor

    SciTech Connect

    Kumar, R.; Maverick, A.W.; Fronczek, F.R.; Kim, A.J.; Butler, L.G.

    1993-12-31

    One of the first successful Cu(I) CVD precursors is (hfac)Cu{sup I}(COD), and this species continues to served as a model system. In the CVD process, a significant step is dissociation of the COD ligand. The energetics of this process have been estimated previously. However, it now appears that, in the solid state, (hfac)Cu{sup I}(COD) undergoes an exchange process that allows additional insight into the potential energy surface governing the Cu-COD interaction. The solid-state structure of (hfac)Cu{sup I}(COD) has been difficult to establish, but a combination of variable temperature X-ray and solid-state {sup 13}C NMR studies leads to the following picture. Cu{sup I} is three-coordinate, bound to the hfac ligand and bound preferentially to one olefin of the COD ligand. There is a small energy barrier associated with motion of the Cu into position for {eta}{sup 2}-binding to the other olefin; the COD and hfac ligands remain approximately stationary. Thus, there are two sites for Cu, now labeled {eta}{sup 2} and {eta}{sup 2}. This new interpretation of the solid-state structure differs from that of our 300 K data set and a previous report. In addition, the exchange process is intimately connected with the Cu-COD dissociation step in the CVD process.

  20. Potential Evapotranspiration as a Source of Uncertainty and Bias in Hydrologic Impact Analyses

    NASA Astrophysics Data System (ADS)

    Milly, P. C. D.

    2015-12-01

    The diversity of commonly used potential evapotranspiration (PET) models contributes uncertainty in the estimation of hydrologic response to anthropogenic climate change. The temperature sensitivity of six commonly used PET equations (Hamon, Oudin, Penman-Monteith, Priestley-Taylor, Samani-Hargreaves, and Thornthwaite) is readily shown to vary by almost an order of magnitude, with energy-unconstrained (i.e., temperature-based) methods showing the largest sensitivity. The change in annual multimodel (Coupled Model Intercomparison Project, Phase 5) PET under Representative Concentration Pathway 8.5 from 1981-2000 to 2081-2100 is typically 10-20% (20-40%) in the low (high) latitudes according to the physics-based Penman-Monteith (ASCE Standardized Reference Evapotranspiration) equation, but 20-40% (20-80%) according to the empirical, temperature-based Hamon equation. Radiation-based Priestley-Taylor changes are smaller than both of these, while empirical, temperature-based Thornthwaite changes are larger than both. These differences in PET change translate to large differences in change of water availability; when combined with a form of the Budyko water-balance relation, the PET methods predict a wide range of runoff changes. Furthermore, all PET methods result in bias that indicates drier conditions globally than those computed by the climate models themselves, and all PET methods overestimate the changes in actual evapotranspiration in non-water-stressed seasons/regions relative to the changes in the climate models. We conclude that use of PET methods that are inappropriate for climate-change applications is a source not only of uncertainty, but also of more drying than suggested by climate models, in hydrologic impact analyses. In view of the bias, it is advised that a no-PET-change analysis be used to define a wet upper bound on potential hydrologic impacts.

  1. Rare decay {eta}{r_arrow}{pi}{pi}{gamma}{gamma} in chiral perturbation theory

    SciTech Connect

    Knoechlein, G.; Scherer, S.; Drechsel, D.

    1996-04-01

    We investigate the rare radiative {eta} decay modes {eta}{r_arrow}{pi}{sup +}{pi}{sup {minus}}{gamma}{gamma} and {eta}{r_arrow}{pi}{sup 0}{pi}{sup 0}{gamma}{gamma} within the framework of chiral perturbation theory at {ital O}({ital p}{sup 4}). We present photon spectra and partial decay rates for both processes as well as a Dalitz contour plot for the charged decay. {copyright} {ital 1996 The American Physical Society.}

  2. Estimating Evapotranspiration with Land Data Assimilation Systems

    NASA Technical Reports Server (NTRS)

    Peters-Lidard, C. D.; Kumar, S. V.; Mocko, D. M.; Tian, Y.

    2011-01-01

    Advancements in both land surface models (LSM) and land surface data assimilation, especially over the last decade, have substantially advanced the ability of land data assimilation systems (LDAS) to estimate evapotranspiration (ET). This article provides a historical perspective on international LSM intercomparison efforts and the development of LDAS systems, both of which have improved LSM ET skill. In addition, an assessment of ET estimates for current LDAS systems is provided along with current research that demonstrates improvement in LSM ET estimates due to assimilating satellite-based soil moisture products. Using the Ensemble Kalman Filter in the Land Information System, we assimilate both NASA and Land Parameter Retrieval Model (LPRM) soil moisture products into the Noah LSM Version 3.2 with the North American LDAS phase 2 (NLDAS-2) forcing to mimic the NLDAS-2 configuration. Through comparisons with two global reference ET products, one based on interpolated flux tower data and one from a new satellite ET algorithm, over the NLDAS2 domain, we demonstrate improvement in ET estimates only when assimilating the LPRM soil moisture product.

  3. NASA GLDAS Evapotranspiration Data and Climatology

    NASA Technical Reports Server (NTRS)

    Rui, Hualan; Beaudoing, Hiroko Kato; Teng, William L.; Vollmer, Bruce; Rodell, Matthew

    2012-01-01

    Evapotranspiration (ET) is the water lost to the atmosphere by evaporation and transpiration. ET is a shared component in the energy and water budget, therefore, a critical variable for global energy and water cycle and climate change studies. However, direct ET measurements and data acquisition are difficult and expensive, especially at the global level. Therefore, modeling is one common alternative for estimating ET. With the goal to generate optimal fields of land surface states and fluxes, the Global Land Data Assimilation System (GLDAS) has been generating quality-controlled, spatially and temporally consistent, terrestrial hydrologic data, including ET and other variables that affect evaporation and transpiration, such as temperature, precipitation, humidity, wind, soil moisture, heat flux, and solar radiation. This poster presents the long-term ET climatology (mean and monthly), derived from the 61-year GLDAS-2 monthly 1.0 deg x 1.0 deg. NOAH model Experiment-1 data, and describes the basic characteristics of spatial and seasonal variations of the climatology. The time series of GLDAS-2 precipitation and radiation, and ET are also discussed to show the improvement of GLDAS-2 forcing data and model output over those from GLDAS-1.

  4. The adaptive CCCG({eta}) method for efficient solution of time dependent partial differential equations

    SciTech Connect

    Campos, F.F.; Birkett, N.R.C.

    1996-12-31

    The Controlled Cholesky factorisation has been shown to be a robust preconditioner for the Conjugate Gradient method. In this scheme the amount of fill-in is defined in terms of a parameter {eta}, the number of extra elements allowed per column. It is demonstrated how an optimum value of {eta} can be automatically determined when solving time dependent p.d.e.`s using an implicit time step method. A comparison between CCCG({eta}) and the standard ICCG solving parabolic problems on general grids shows CCCG({eta}) to be an efficient general purpose solver.

  5. Measurements of the mass and width of the eta(c) meson and of an eta(c)(2S) candidate.

    PubMed

    Aubert, B; Barate, R; Boutigny, D; Gaillard, J-M; Hicheur, A; Karyotakis, Y; Lees, J P; Robbe, P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kral, J F; Kukartsev, G; LeClerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Romosan, A; Ronan, M T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Knowles, D J; Morgan, S E; Penny, R C; Watson, A T; Watson, N K; Deppermann, T; Goetzen, K; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmuecker, H; Steinke, M; Barlow, N R; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Mackay, C; Wilson, F F; Abe, K; Cuhadar-Donszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; McKemey, A K; Blinov, V E; Bukin, A D; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Shen, B C; Del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, Sh; Schwanke, U; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Kuznetsova, N; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Beringer, J; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Turri, M; Walkowiak, W; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Roy, J; Smith, J G; Van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Soffer, A; Toki, W H; Wilson, R J; Zhang, J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Dubitzky, R S; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Schubert, J; Schubert, K R; Schwierz, R; Spaan, B; Wilden, L; Bernard, D; Bonneaud, G R; Brochard, F; Cohen-Tanugi, J; Grenier, P; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Khan, A; Lavin, D; Muheim, F; Playfer, S; Swain, J E; Tinslay, J; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Anulli, F; Baldini-Ferroli, R; Biasini, M; Calcaterra, A; De Sangro, R; Falciai, D; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Pioppi, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Morii, M; Won, E; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Eschrich, I; Gaillard, J R; Morton, G W; Nash, J A; Sanders, P; Taylor, G P; Grenier, G J; Lee, S-J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Brigljević, V; Cheng, C H; Lange, D J; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, E; Gamet, R; Kay, M; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Harrison, P F; Shorthouse, H W; Strother, P; Vidal, P B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; George, S; Green, M G; Kurup, A; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, R J; Forti, A C; Hart, P A; Jackson, F; Lafferty, G D; Lyon, A J; Weatherall, J H; Williams, J C; Farbin, A; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Milek, M; Patel, P M; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Cote-Ahern, D; Hast, C; Taras, P; Nicholson, H; Cartaro, C; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; LoSecco, J M; Gabriel, T A; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Wong, Q K; Brau, J; Frey, R; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; de la Vaissière, Ch; Del Buono, L; Hamon, O; John, M J J; Leruste, Ph; Ocariz, J; Pivk, M; Roos, L; Stark, J; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martinez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lu, C; Miftakov, V; Olsen, J; Smith, A J S; Tanaka, H A; Varnes, E W; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Safai Tehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Geddes, N I; Gopal, G P; Olaiya, E O; Xella, S M; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P-F; Hamel de Monchenault, G; Kozanecki, W; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yeche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Convery, M R; Coupal, D P; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Grauges-Pous, E; Hadig, T; Halyo, V; Hryn'ova, T; Innes, W R; Jessop, C P; Kelsey, M H; Kim, P; Kocian, M L; Langenegger, U; Leith, D W G S; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Robertson, S H; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Va'vra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wright, D H; Young, C C; Burchat, P R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, S; Alam, M S; Ernst, J A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihalyi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; von Wimmersperg-Toeller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H

    2004-04-01

    The mass m(eta(c)) and total width Gamma(eta(c))(tot) of the eta(c) meson have been measured in two-photon interactions at the SLAC e(+)e(-) asymmetric B Factory with the BABAR detector. With a sample of approximately 2500 reconstructed eta(c)-->K(0)(S)K+/-pi(-/+) decays in 88 fb(-1) of data, the results are m(eta(c))=2982.5+/-1.1(stat)+/-0.9(syst) MeV/c(2) and Gamma(eta(c))(tot)=34.3+/-2.3(stat)+/-0.9(syst) MeV/c(2). Using the same decay mode, a second resonance with 112+/-24 events is observed with a mass of 3630.8+/-3.4(stat)+/-1.0(syst) MeV/c(2) and width of 17.0+/-8.3(stat)+/-2.5(syst) MeV/c(2). This observation is consistent with expectations for the eta(c)(2S) state. PMID:15089530

  6. Mapping Evapotranspiration on Vineyards: The SENTINEL-2 Potentiality

    NASA Astrophysics Data System (ADS)

    Ciraolo, Giuseppe; Capodici, Fulvio; D'Urso, Guido; La Loggia, Goffredo; Maltese, Antonino

    2012-04-01

    Estimation of actual evapotranspiration in Sicilian vineyards, is an emerging issue since these agricultural systems. Indeed unlike other agricultural species (Vitis vinifera L.) are generally cultivated under mild water stress, in order to enhance quality (Guadillère et al., 2002. This has significant impacts on the management of the scarce water resources of the region. The choice of the most appropriate methodology for assessing water use in these systems is still an issue of debating, due to the complexity of canopy and root systems and for their high spatial fragmentation. In vineyards, quality and quantity of the final product are dependent on the controlled stress conditions to be set trough irrigation. This paper reports an application of the well-known Penman-Monteith approach, applied in a distributed way, using high resolution remote sensing data to map the potential evapotranspiration (ETp). In 2008 a series of airborne multispectral images were acquired on the "Tenute Rapitalà", a wine farm located in the northwest of Sicily. Five airborne remote sensing scenes were collected using a SKY ARROW 351 650 TC/TCNS aircraft, at a height of about 1000 m a.g.l.. The acquisitions encompassed almost a whole phenological period, between June and September 2008 (approximately one each three weeks). The platform had on board a multi-spectral camera with 3 spectral bands in the green (G, 530-570 nm), red (R, 650-690 nm) and near infrared (NIR, 767-832 nm) wavelengths, and a thermal camera with a broad band in the range 7.5-13 μm. The nominal pixel resolution was approximately 0.7 m for VIS/NIR acquisitions, and 1.7 m for the thermal-IR data. Field data were acquired simultaneously to airborne acquisitions. The former include spectral reflectance in visible, near infrared, middle infrared (VIS, NIR, MIR) regions of the spectrum, leaf area index (LAI), soil moisture at different depths (both in row and below plants). Moreover, meteorological variables and fluxes

  7. Surface Energy Balance Based Evapotranspiration Mapping in the Texas High Plains

    PubMed Central

    Gowda, Prasanna H.; Chávez, José L.; Howell, Terry A.; Marek, Thomas H.; New, Leon L.

    2008-01-01

    Agriculture on the Texas High Plains (THP) uses approximately 89% of groundwater withdrawals from the Ogallala Aquifer. Consequently, groundwater levels are declining faster than the recharge rate. Therefore, efficient agricultural water use is essential for economic viability and sustainability of the THP. Accurate regional evapotranspiration (ET) maps would provide valuable information on actual crop water use. In this study, METRIC (Mapping Evapotranspiration at High Resolution using Internalized Calibration), a remote sensing based ET algorithm, was evaluated for mapping ET in the THP. Two Landsat 5 Thematic Mapper images acquired on 27 June (DOY 178) and 29 July (DOY 210) 2005 were used for this purpose. The performance of the ET model was evaluated by comparing the predicted daily ET with values derived from soil moisture budget at four commercial agricultural fields. Daily ET estimates resulted with a prediction error of 12.7±8.1% (mean bias error ± root mean square error) on DOY 178 and -4.7±9.4% on DOY 210 when compared with ET derived from measured soil moisture through the soil water balance. These results are good considering the prevailing advective conditions in the THP. METRIC have the potential to be used for mapping regional ET in the THP region. However, more evaluation is needed under different agroclimatological conditions.

  8. Comparing SEBAL and METRIC: Evapotranspiration Models Applied to Paramount Farms Almond Orchards

    NASA Astrophysics Data System (ADS)

    Furey, B. J.; Kefauver, S. C.

    2011-12-01

    Two evapotranspiration models were applied to almond and pistachio orchards in California. The SEBAL model, developed by W.G.M. Bastiaanssen, was programmed in MatLab for direct comparison to the METRIC model, developed by R.G. Allen and the IDWR. Remote sensing data from the NASA SARP 2011 Airborne Research Program was used in the application of these models. An evaluation of the models showed that they both followed the same pattern in evapotranspiration (ET) rates for different types of ground cover. The models exhibited a slightly different range of values and appeared to be related (non-linearly). The models both underestimated the actual ET at the CIMIS weather station. However, SEBAL overestimated the ET of the almond orchards by 0.16 mm/hr when applying its crop coefficient to the reference ET. This is compared to METRIC, which underestimated the ET of the almond orchards by only 0.10 mm/hr. Other types of ground cover were similarly compared. Temporal variability in ET rates between the morning and afternoon were also observed.

  9. Using Satellite-based Evapotranspiration Estimation to Characterize Agricultural Irrigation Water Use

    NASA Astrophysics Data System (ADS)

    Zheng, B.; Myint, S. W.; Hendrickx, J. M. H.

    2014-12-01

    The satellite-based evapotranspiration (ET) model permits estimation of water consumption across space and time in a systematic way. Developing tools to monitor water availability and water use is critical to meet future water shortage challenges in the American West. This study applied METRIC (Mapping Evapotranspiration at high Resolution and with Internalized Calibration) to 2001 Landsat imagery to estimate ET of various crop types in Phoenix. The total annual ET estimates are correlated well with the actual water use at the irrigation district level (r=0.99). We further incorporated a crop type map to estimate annual ET for the major crop types in the region, and to examine variability in crop water use among different irrigation districts. Our results show that alfalfa and double crops consume more water than other crop types with mean annual ET estimations of 1300 to 1580 mm/year, and that cotton uses more water (1162 mm/year) than corn (838 mm/year) and sorghum (829 mm/year) as expected. Crop water use varies from one irrigation district to another due to differences in soil quality, water quality, and farming practices. Results from our study suggest that the ET maps derived from METRIC can be used to quantify the spatial distribution of ET and to characterize agricultural water use by crop types at different spatial scales.

  10. Statistical Analysis of Meteorological Data to Assess Evapotranspiration and Infiltration at the Rifle Site, CO, USA

    NASA Astrophysics Data System (ADS)

    Faybishenko, B.; Long, P. E.; Tokunaga, T. K.; Christensen, J. N.

    2015-12-01

    Net infiltration to the vadose zone, especially in arid or semi-arid climates, is an important control on microbial activity and solute and green house gas fluxes. To assess net infiltration, we performed a statistical analysis of meteorological data as the basis for hydrological and climatic investigations and predictions for the Rifle site, Colorado, USA, located within a floodplain in a mountainous region along the Colorado River, with a semi-arid climate. We carried out a statistical analysis of meteorological 30-year time series data (1985-2015), including: (1) precipitation data, taking into account the evaluation of the snowmelt, (2) evaluation of the evapotranspiration (reference and actual), (3) estimation of the multi-time-scalar Standardized Precipitation-Evapotranspiration Index (SPEI), (4) evaluation of the net infiltration rate, and (5) corroborative analysis of calculated net infiltration rate and groundwater recharge from radioisotopic measurements from samples collected in 2013. We determined that annual net infiltration percentage of precipitation varies from 4.7% to ~18%, with a mean of ~10%, and concluded that calculations of net infiltration based on long-term meteorological data are comparable with those from strontium isotopic investigations. The evaluation of the SPEI showed the intermittent pattern of droughts and wet periods over the past 30 years, with a detectable decreasein the duration of droughts with time. Local measurements within the floodplain indicate a recharge gradient with increased recharge closer to the Colorado River.

  11. How People Actually Use Thermostats

    SciTech Connect

    Meier, Alan; Aragon, Cecilia; Hurwitz, Becky; Mujumdar, Dhawal; Peffer, Therese; Perry, Daniel; Pritoni, Marco

    2010-08-15

    Residential thermostats have been a key element in controlling heating and cooling systems for over sixty years. However, today's modern programmable thermostats (PTs) are complicated and difficult for users to understand, leading to errors in operation and wasted energy. Four separate tests of usability were conducted in preparation for a larger study. These tests included personal interviews, an on-line survey, photographing actual thermostat settings, and measurements of ability to accomplish four tasks related to effective use of a PT. The interviews revealed that many occupants used the PT as an on-off switch and most demonstrated little knowledge of how to operate it. The on-line survey found that 89% of the respondents rarely or never used the PT to set a weekday or weekend program. The photographic survey (in low income homes) found that only 30% of the PTs were actually programmed. In the usability test, we found that we could quantify the difference in usability of two PTs as measured in time to accomplish tasks. Users accomplished the tasks in consistently shorter times with the touchscreen unit than with buttons. None of these studies are representative of the entire population of users but, together, they illustrate the importance of improving user interfaces in PTs.

  12. Recent changes in reference evapotranspiration in Romania

    NASA Astrophysics Data System (ADS)

    Croitoru, Adina-Eliza; Piticar, Adrian; Dragotă, Carmen Sofia; Burada, Doina Cristina

    2013-12-01

    In the last few decades, climate changes have become the most important topic in the field of climatology. Reference evapotranspiration (ET0) is often used to identify regions prone to drought or aridity. In this paper, we used monthly data recorded in 57 weather stations in Romania over the period 1961-2007. The FAO Penman-Monteith method, based on air temperature, sunshine duration, relative humidity and wind speed, was employed in order to calculate ET0. Seasonal, annual, winter wheat and maize growing seasons data sets of ET0 were generated. The trends were detected using the Mann-Kendall test and Sen's slope, while an ArcGIS software was employed for mapping the results. The main findings of the study are: positive slopes were found in 71% of the data series considered and almost 30% of the total number of series were found significant at α = 0.05; the highest frequency of the increasing trends as well as their absolute maximum magnitude were detected during summer and maize growing season; in winter, significant increasing changes are specific mainly to the extra-Carpathians regions; in autumn decreasing ET0 is specific to more than 80% of the locations, but the significant decrease characterizes mainly the southern half of the country; during the growing seasons of maize and winter wheat, the increase of the ET0 is dominant for the entire country. The relative change decreases with the increase of the length of the period considered: the most intense changes were detected for climatic seasons, followed by crop growing seasons and annual values. Among the climatic seasons, the highest relative increase is specific to winter followed by summer, spring and autumn, while for the crop growing seasons the values detected are similar.

  13. Evapotranspiration of tropical peat swamp forests.

    PubMed

    Hirano, Takashi; Kusin, Kitso; Limin, Suwido; Osaki, Mitsuru

    2015-05-01

    In Southeast Asia, peatland is widely distributed and has accumulated a massive amount of soil carbon, coexisting with peat swamp forest (PSF). The peatland, however, has been rapidly degraded by deforestation, fires, and drainage for the last two decades. Such disturbances change hydrological conditions, typically groundwater level (GWL), and accelerate oxidative peat decomposition. Evapotranspiration (ET) is a major determinant of GWL, whereas information on the ET of PSF is limited. Therefore, we measured ET using the eddy covariance technique for 4-6 years between 2002 and 2009, including El Niño and La Niña events, at three sites in Central Kalimantan, Indonesia. The sites were different in disturbance degree: a PSF with little drainage (UF), a heavily drained PSF (DF), and a drained burnt ex-PSF (DB); GWL was significantly lowered at DF, especially in the dry season. The ET showed a clear seasonal variation with a peak in the mid-dry season and a large decrease in the late dry season, mainly following seasonal variation in net radiation (Rn ). The Rn drastically decreased with dense smoke from peat fires in the late dry season. Annual ET forced to close energy balance for 4 years was 1636 ± 53, 1553 ± 117, and 1374 ± 75 mm yr(-1) (mean ± 1 standard deviation), respectively, at UF, DF, and DB. The undrained PSF (UF) had high and rather stable annual ET, independently of El Niño and La Niña events, in comparison with other tropical rainforests. The minimum monthly-mean GWL explained 80% of interannual variation in ET for the forest sites (UF and DF); the positive relationship between ET and GWL indicates that drainage by a canal decreased ET at DF through lowering GWL. In addition, ET was decreased by 16% at DB in comparison with UF chiefly because of vegetation loss through fires. PMID:24912043

  14. Scaling Potential Evapotranspiration with Greenhouse Warming (Invited)

    NASA Astrophysics Data System (ADS)

    Scheff, J.; Frierson, D. M.

    2013-12-01

    Potential evapotranspiration (PET) is a supply-independent measure of the evaporative demand of a terrestrial climate, of basic importance in climatology, hydrology, and agriculture. Future increases in PET from greenhouse warming are often cited as key drivers of global trends toward drought and aridity. The present work computes recent and business-as-usual-future Penman-Monteith (i.e. physically-based) PET fields at 3-hourly resolution in 14 modern global climate models. The %-change in local annual-mean PET over the upcoming century is almost always positive, modally low double-digit in magnitude, usually increasing with latitude, yet quite divergent between models. These patterns are understood as follows. In every model, the global field of PET %-change is found to be dominated by the direct, positive effects of constant-relative-humidity warming (via increasing vapor pressure deficit and increasing Clausius-Clapeyron slope.) This direct-warming term very accurately scales as the PET-weighted (warm-season daytime) local warming, times 5-6% per degree (related to the Clausius-Clapeyron equation), times an analytic factor ranging from about 0.25 in warm climates to 0.75 in cold climates, plus a small correction. With warming of several degrees, this product is of low double-digit magnitude, and the strong temperature dependence gives the latitude dependence. Similarly, the inter-model spread in the amount of warming gives most of the spread in this term. Additional spread in the total change comes from strong disagreement on radiation, relative-humidity, and windspeed changes, which make smaller yet substantial contributions to the full PET %-change fields.

  15. Bryophyte Evapotranspiration in a Boreal Forest Chronosequence

    NASA Astrophysics Data System (ADS)

    Bond-Lamberty, B.; Ewers, B.; Angstmann, J.; Gower, S.

    2008-12-01

    Forest water fluxes, in particular evapotranspiration (ET), are less well constrained than are carbon fluxes, and the effect of changing stand age on forest ET is not well understood. We combined field and lab measurements to estimate the bryophyte contribution to ET in a black spruce-dominated boreal chronosequence in Manitoba, Canada. Site ages were 17, 42, 76 and 156 years, and each site contained separate well- and poorly-drained stands (bogs). Field plots (N=4) were surveyed for moss diversity and microtopography; meteorological variables were recorded continuously. Field measurements were made 3-4 times during the growing season using a custom chamber attached to a LI-COR 6400. In addition, large tubs of moss were incubated in a controlled-environment chamber and water loss rates measured via weighing; these tubs were also measured using the same protocol as performed in the field. In the lab, fully-saturated feathermoss and Sphagnum lost water at rates as high as 1.5 and 4.5 mm day-1, respectively, at 25 °C. Over the entire year, modeled bryophyte ET ranged from 0.2-0.3 and 0.2-0.5 mm day-1 in the well- and poorly-drained stands, respectively. During the growing season, these rates were 0.7-0.8 and 0.6- 1.4 mm day-1. Ignoring bog microtopography would have resulted in underestimation of fluxes by ~10%. There was no clear trend of moss ET flux with stand age, except at the very youngest stands, where bryophyte spatial coverage was low. Our results emphasize the important contribution that bryophytes make to the ET flux of boreal forests.

  16. Eta Carinae, the Integral Nebula and the Homunculus Observations

    NASA Astrophysics Data System (ADS)

    Gull, Theodore

    2000-07-01

    In the past two years, observations of Eta Carina have revealed much new and very exciting information. Augusto Damineli noted a 5.5 year period in the visible and near infrared spectroscopy. Michael Corcoran and Bish Ishibashi noticed modulation of the x-ray fluxes with various periodicities around 90 days before and after the xray and radio minimum in December 1997. Observations, done in March 1998 under proposal 7302 {Davidson et al} from 1640A to 10400A using STIS in GXXXM mode and the 50x0.1 arcsecond slit, revealed much new information in the immediate regions of Eta Carina. The slit orientation was slightly off the major axis of the Homunculus, but passed through Weigelt components B and D. Bish Ishibashi and Ted Gull have reduced the data and provided it to various team members. Torgil Zethson has identified well over 90 percent of the emission lines in the March 1998 spectrum and finds most to be FeII emission lines. Based upon the past ground-based history of Eta Carina, we expected that FeIII and other high ionization states would return within the year. STIS GTO observations {Ted Gull, PI program 8036} characterized a bright internal emission nebula by turning the slit 90 degrees for visit 1 and studying the changes in spectrum as the FeIII lines appear by using visit 2 with the identical slit orientation from March 19, 1998. Data from the four visits of STIS to Eta Carinae between December 1997 and February 1999 demonstrate that the star has brightened by a factor of two during that interval and that the immediate nebulosity has tripled in surface brightness. Moreover a small circular nebular shell, seen in multiple [Fe II] lines has disappeared and the opacity in the 2000 to 3000A region obscuring the star has lifted considerable as the Fe II is converting to Fe III. Given the strong changes in the spectrum, we have chosen to use the six orbits in two visits. Visit 1 will be a precise repeat of the March 1998 and February 1999 observations, adjusted

  17. Endothelin ETA receptor expression in human cerebrovascular smooth muscle cells.

    PubMed Central

    Yu, J. C.; Pickard, J. D.; Davenport, A. P.

    1995-01-01

    1. Endothelin (ET) has been implicated in cerebrovasospasm for example, following subarachnoid haemorrhage, and blocking the interaction of ET with its receptors on cerebral vessels, may be of therapeutic benefit. The aim of our study was to characterize endothelin receptor sub-types on medial smooth muscle cells of human cerebral vessels. Cultures of vascular smooth muscle cells were explanted from human cerebral resistance vessels and characterized as human brain smooth muscle cells (HBSMCs). 2. Over a 48 h incubation period, HBSMC cultures secreted comparable levels of immunoreactive (IR) big endothelin-1 (big ET-1) and IR endothelin (ET): 12.7 +/- 10.3 and 8.3 +/- 5.6 pmol/10(6) cells, respectively (mean +/- s.e. mean from three different individuals), into the culture medium. 3. Total RNA was extracted from cultures of human brain smooth muscle cells. Reverse-transcriptase polymerase chain reaction (RI-PCR) assays and subsequent product separation by agarose gel electrophoresis revealed single bands corresponding to the expected product sizes encoding cDNA for ETA (299 base pairs) and ETB (428 base pairs) (n = 3 different cultures). 4. Autoradiography demonstrated the presence of specific binding sites for [125I]-ET-1 which labels all ET receptors, and [125I]-PD151242, an ETA subtype-selective antagonist which exclusively labels ETA receptors, but no specific-binding was detected using ETB subtype-selective [125I]-BQ3020 (n = 3 different cultures, in duplicate). 5. In saturation binding assays, [123I]-ET-1 bound with high affinity: KD = 0.8 +/- 0.1 nM and Bmax = 690 +/- 108 fmol mg-1. A one-site fit was preferred and Hill slopes were close to unity over the concentration range (10(-12) to 10(-8) M). [125I]-PD151242 also bound with similar affinity: KD = 0.4 +/- 0.1 nM and Bmax = 388 +/- 68 fmol mg-1 (mean +/- s.e. mean, n = 3 different cultures). Again, a one-site fit was preferred and Hill slopes were close to unity over the concentration range. Unlabelled PD

  18. The {eta}(2225) observed by the BES Collaboration

    SciTech Connect

    Li Demin; Ma Bing

    2008-05-01

    In the framework of the {sup 3}P{sub 0} meson decay model, the strong decays of the 3{sup 1}S{sub 0} and 4{sup 1}S{sub 0} ss states are investigated. It is found that in the presence of the initial state mass being 2.24 GeV, the total widths of the 3{sup 1}S{sub 0} and 4{sup 1}S{sub 0} ss states are about 438 MeV and 125 MeV, respectively. Also, when the initial state mass varies from 2220 to 2400 MeV, the total width of the 4{sup 1}S{sub 0} ss state varies from about 100 to 132 MeV, while the total width of the 3{sup 1}S{sub 0} ss state varies from about 400 to 594 MeV. A comparison of the predicted widths and the experimental result of (0.19{+-}0.03{sub -0.06}{sup +0.04}) GeV, the width of the {eta}(2225) with a mass of (2.24{sub -0.02-0.02}{sup +0.03+0.03}) GeV recently observed by the BES Collaboration in the radiative decay J/{psi}{yields}{gamma}{phi}{phi}{yields}{gamma}K{sup +}K{sup -}K{sub S}{sup 0}K{sub L}{sup 0}, suggests that it would be very difficult to identify the {eta}(2225) as the 3{sup 1}S{sub 0} ss state, and the {eta}(2225) seams a good candidate for the 4{sup 1}S{sub 0} ss state.

  19. UV nebular absorption in Eta Car and Weigelt D

    NASA Astrophysics Data System (ADS)

    Nielsen, K. E.; Vieira, G. L.; Gull, T. R.; Lindler, D. J.; Eta Car HST Treasury Team

    2003-12-01

    The high angular and high spectral resolution of the HST/STIS MAMA echelle mode, provide an unique means to distinguish the physical structures surrounding Eta Car. Observations are parts of the HST treasury program (K. Davidson P.I.) for monitoring variations over Eta Car's spectroscopic minimum. Nebular emission is present above and below the stellar spectrum which is about 0.03'' wide. We have extracted the nebular part of the central source spectrum and compared it with the spectrum of Weigelt D, located approximately 0.2'' Northwest of the central source. The spectra show significant similarities and our conclusions are two-fold. First, the radiation from the Wiegelt blobs give an unwanted contribution to the spectrum of the central source, which emphasizes the importance of using an extracted spectrum in a spectral analysis. Second, the Weigelt blobs have so far been assumed to produce a pure emission line spectrum. However, this comparison shows the presence of similar absorption structures previously observed in the spectrum of the central star (Gull et al., 2003, submitted ApJL). Two velocity structures at approximately -50 and -500 km/s, respectively, have been observed in the Weigelt D spectrum. We present identifications of the absorption structures to supplement the emission line work performed by T. Zethson (2000, PhD Thesis) and provide additional information regarding the geometry of the inner parts of the Eta Car nebula. The -50 km/s velocity component is similar to the absorption structure at -146 km/s observed in the spectrum of the central object. If these velocity systems are related, this implies that the absorption component is located close to the central parts of the nebular system.

  20. Nebular Hydrogen Absorption in the Ejecta of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Ishibashi, K.; Davidson, K.; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    Space Telescope Imaging Spectrograph (STIS) observations of Eta Carinae and immediate ejecta reveal narrow Balmer absorption lines in addition to the nebular-scattered broad P-Cygni absorptions. The narrow absorption correlates with apparent disk structure that separates the two Homunculus lobes. We trace these features about half way up the Northern lobe until the scattered stellar Balmer line doppler-shifts redward beyond the nebular absorption feature. Three-dimensional data cubes, made by mapping the Homunculus at Balmer alpha and Balmer beta with the 52 x 0.1 arcsecond aperture and about 5000 spectral resolving power, demonstrate that the absorption feature changes slowly in velocity with nebular position. We have monitored the stellar Balmer alpha line profile of the central source over the past four years. The equivalent width of the nebular absorption feature changes considerably between observations. The changes do not correlate with measured brightness of Eta Carinae. Likely clumps of neutral hydrogen with a scale size comparable to the stellar disk diameter are passing through the intervening light path on the timescales less than several months. The excitation mechanism involves Lyman alpha radiation (possibly the Lyman series plus Lyman continuum) and collisions leading to populating the 2S metastable state. Before the electron can jump to the ground state by two photon emission (lifetime about 1/8 second), a stellar Balmer photon is absorbed and the electron shifts to an NP level. We see the absorption feature in higher Balmer lines, and but not in Paschen lines. Indeed we see narrow nebular Paschen emission lines. At present, we do not completely understand the details of the absorption. Better understanding should lead to improved insight of the unique conditions around Eta Carinae that leads to these absorptions.

  1. [Sr II] Detected in a Nebular Filament Near Eta Carinae

    NASA Technical Reports Server (NTRS)

    Gull, T.R.; Fisher, Richard (Technical Monitor)

    2000-01-01

    Observations with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope reveal a peculiar emission line region in the close vicinity to Eta Carinae. The lines of [SrII], [MnII], [CoII], [TiII], [NiII] and [FeI] are detected in the 6400-7000 Angstrom spectral interval at a blue-shifted velocity of approximately 95 km/sec and seem to be associated with a long, narrow filament with dimensions of less than 0.5 inches by 1.1 inches. The filament is notable as it is separate both in velocity and structure from the bright emission of the Integral Nebula. This filament is buried within the Homunculus and is not visible in direct images which are dominated by reflection nebulosities. In our literature searches we have found no evidence of strontium emission lines in nebulae. We are aware of permitted transitions of strontium seen in AGB stars. S-processed elements like strontium are not expected in the ejecta of a massive star like Eta Carinae. Detection of [SrII] and the fact that the [NiII], [MnII] and [CoII] lines are unusually strong compared to [FeI] are quite a surprise. It has long been known that nitrogen is overabundant in the ejecta of Eta Carinae. Is this processed material from the present star(s)? Has there been processed material ejected from a more evolved companion? The situation is decidedly mysterious. This research has been supported by NASA through STScI grants and the STIS GTO funding.

  2. THE LONG-LIVED DISKS IN THE {eta} CHAMAELEONTIS CLUSTER

    SciTech Connect

    Sicilia-Aguilar, Aurora; Bouwman, Jeroen; Juhasz, Attila; Henning, Thomas; Roccatagliata, Veronica; Lawson, Warrick A.; Acke, Bram; Decin, Leen; Feigelson, Eric D.; Tielens, A. G. G. M.; Meeus, Gwendolyn

    2009-08-20

    We present Infrared Spectrograph spectra and revised Multiband Imaging Photometer photometry for the 18 members of the {eta} Chamaeleontis cluster. Aged 8 Myr, the {eta} Cha cluster is one of the few nearby regions within the 5-10 Myr age range, during which the disk fraction decreases dramatically and giant planet formation must come to an end. For the 15 low-mass members, we measure a disk fraction {approx}50%, high for their 8 Myr age, and four of the eight disks lack near-IR excesses, consistent with the empirical definition of 'transition' disks. Most of the disks are comparable to geometrically flat disks. The comparison with regions of different ages suggests that at least some of the 'transition' disks may represent the normal type of disk around low-mass stars. Therefore, their flattened structure and inner holes may be related to other factors (initial masses of the disk and the star, environment, binarity), rather than to pure time evolution. We analyze the silicate dust in the disk atmosphere, finding moderate crystalline fractions ({approx}10%-30%) and typical grain sizes {approx}1-3 {mu}m, without any characteristic trend in the composition. These results are common to other regions of different ages, suggesting that the initial grain processing occurs very early in the disk lifetime (<1 Myr). Large grain sizes in the disk atmosphere cannot be used as a proxy for age, but are likely related to higher disk turbulence. The dust mineralogy varies between the 8-12 {mu}m and the 20-30 {mu}m features, suggesting high temperature dust processing and little radial mixing. Finally, the analysis of IR and optical data on the B9 star {eta} Cha reveals that it is probably surrounded by a young debris disk with a large inner hole, instead of being a classical Be star.

  3. Validating HYLARSMET: a Hydrologically Consistent Land Surface Model for Soil Moisture and Evapotranspiration Modelling over Southern Africa using Remote Sensing and Meteorological Data

    NASA Astrophysics Data System (ADS)

    Sinclair, Scott; Pegram, Geoff; Mengitsu, Michael; Everson, Colin

    2015-04-01

    Timeous knowledge of the spatial distribution of soil moisture and evapotranspiration over a large region in fine detail has great value for coping with two weather extremes: flash floods and droughts, since the state of the wetness of the land surface has a major impact on runoff response. Also, the ability to monitor the wetness of the soil and the actual evapotranspiration over large regions, without having to laboriously take expensive samples, is a bonus for agricultural managers who need to predict crop yields. We present samples of the daily national Soil Moisture and Evapotranspiration estimates on a grid of 7300 locations centred in 12 km squares, then move on to the results of a validation study for soil moisture and evapotranspiration estimated using the PyTOPKAPI hydrological model in Land Surface Modelling mode, a system called HYLARSMET. The HYLARSMET estimates are compared with detailed evapotranspiration and soil moisture measurements made at the Baynesfield experimental farm in the KwaZulu-Natal province of South Africa, run by the University of KZN. The HYLARSMET evapotranspiration estimates compared very well with the measured estimates for the two chosen crop types, in spite of the fact that the HYLARSMET estimates were not designed to explicitly account for the crop types at each site. The same seasonality effects were evident in all 3 estimates, and there was a stronger ET relationship between HYLARSMET and the Soybean site (Pearson r = 0.81) than for Maize, (r = 0.59). The soil moisture relationship was stronger between the two in situ measured estimates (r = 0.98 at 0.5 m depth) than it was between HYLARSMET and the field estimates (r about 0.52 in both cases). Overall there was a reasonably good relationship between HYLARSMET and the in situ measurements of ET and SM at each site, indicating the value of the modelling procedure.

  4. Investigation of Climate Change Impact on Water Resources for an Alpine Basin in Northern Italy: Implications for Evapotranspiration Modeling Complexity

    PubMed Central

    Ravazzani, Giovanni; Ghilardi, Matteo; Mendlik, Thomas; Gobiet, Andreas; Corbari, Chiara; Mancini, Marco

    2014-01-01

    Assessing the future effects of climate change on water availability requires an understanding of how precipitation and evapotranspiration rates will respond to changes in atmospheric forcing. Use of simplified hydrological models is required beacause of lack of meteorological forcings with the high space and time resolutions required to model hydrological processes in mountains river basins, and the necessity of reducing the computational costs. The main objective of this study was to quantify the differences between a simplified hydrological model, which uses only precipitation and temperature to compute the hydrological balance when simulating the impact of climate change, and an enhanced version of the model, which solves the energy balance to compute the actual evapotranspiration. For the meteorological forcing of future scenario, at-site bias-corrected time series based on two regional climate models were used. A quantile-based error-correction approach was used to downscale the regional climate model simulations to a point scale and to reduce its error characteristics. The study shows that a simple temperature-based approach for computing the evapotranspiration is sufficiently accurate for performing hydrological impact investigations of climate change for the Alpine river basin which was studied. PMID:25285917

  5. Implementation of an Eta Belt Domain on Parallel Systems

    NASA Technical Reports Server (NTRS)

    Kouatchou, Jules; Rancic, Miodrag; Norris, Peter; Geiger, Jim

    2001-01-01

    We extend the Eta weather model from a regional domain into a belt domain that does not require meridional boundary conditions. We describe how the extension is achieved and the parallel implementation of the code on the Cray T3E and the SGI Origin 2000. We validate the forecast results on the two platforms and examine how the removal of the meridional boundary conditions affects these forecasts. In addition, using several domains of different sizes and resolutions, we present the scaling performance of the code on both systems.

  6. Eta Carinae in the Context of the Most Massive Stars

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Damineli, Augusto

    2009-01-01

    Eta Car, with its historical outbursts, visible ejecta and massive, variable winds, continues to challenge both observers and modelers. In just the past five years over 100 papers have been published on this fascinating object. We now know it to be a massive binary system with a 5.54-year period. In January 2009, Car underwent one of its periodic low-states, associated with periastron passage of the two massive stars. This event was monitored by an intensive multi-wavelength campaign ranging from -rays to radio. A large amount of data was collected to test a number of evolving models including 3-D models of the massive interacting winds. August 2009 was an excellent time for observers and theorists to come together and review the accumulated studies, as have occurred in four meetings since 1998 devoted to Eta Car. Indeed, Car behaved both predictably and unpredictably during this most recent periastron, spurring timely discussions. Coincidently, WR140 also passed through periastron in early 2009. It, too, is a intensively studied massive interacting binary. Comparison of its properties, as well as the properties of other massive stars, with those of Eta Car is very instructive. These well-known examples of evolved massive binary systems provide many clues as to the fate of the most massive stars. What are the effects of the interacting winds, of individual stellar rotation, and of the circumstellar material on what we see as hypernovae/supernovae? We hope to learn. Topics discussed in this 1.5 day Joint Discussion were: Car: the 2009.0 event: Monitoring campaigns in X-rays, optical, radio, interferometry WR140 and HD5980: similarities and differences to Car LBVs and Eta Carinae: What is the relationship? Massive binary systems, wind interactions and 3-D modeling Shapes of the Homunculus & Little Homunculus: what do we learn about mass ejection? Massive stars: the connection to supernovae, hypernovae and gamma ray bursters Where do we go from here? (future

  7. Stratified X-ray Plasmas around Eta Carinae

    NASA Astrophysics Data System (ADS)

    Hamaguchi, Kenji; Corcoran, Michael

    At a distance of ˜2.3 kpc, eta Carinae is the best super massive star to study the LBV phenomenon. It is a binary composed of two massive stars on a highly elliptical orbit (e ˜0.9-0.95, P˜5.54 years). The current best estimate is that the primary star has M gtrsim90M_{⊙} and v_{wind} ˜420 km s(-1) , while the companion star has M˜30M_{⊙} and v_{wind} ˜3000 km s(-1) . Strong winds from both stars collide (the wind-wind collision: WWC), which produces hot thermal plasmas of kT˜4 keV and emits strong X-rays. The luminosity increases toward periastron, but it abruptly declines by two orders of magnitudes around periastron. We had an observing campaign of eta Car around periastron in 2009.0, which revealed that the X-ray decline is caused by a hybrid mechanism of a true eclipse and an activity decay of the WWC plasma. During the activity decay, the head-on wind collision seems to shut off, possibly due to the overwhelming momentum of the primary wind. The secondary winds flowing backward may still collide with the twisted primary winds and produce hot X-ray plasma. During the eclipse of the WWC plasma, faint X-ray emission from a different plasma component within ˜500 AU from eta Car emerged. The plasma is as hot as the WWC plasma (˜50 MK) and in strong non-equilibrium ionization state (nt ≤sssim4×10(10) cm(-3) s). The plasma may originate from collision of winds ejected a few orbits ago. Inside the bipolar lobe of eta Car, the Chandra observatory spatially resolved emission from extended hot cool (˜6 MK) plasmas, as well as the X-ray reflection component. The spectrum showed unusually strong lines around the Si and S K-shell energies, which may be originated in the collision of the secondary winds with cold circumstellar material. We discuss the circumstellar hot plasma structures of LBVs based on these results.

  8. Eta Carinae and the Homunculus: A Physics Laboratory

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Fisher, Richard R. (Technical Monitor)

    2002-01-01

    The Luminous Blue Variable, Eta Carinae, and its ejecta, thrown out since the 1840s, are proving to be a very challenging system to explain. The > 100 solar mass central source (which is likely a binary system) is very complex with P-Cygni lines throughout the spectrum. Superimposed upon the stellar spectrum are many thousands of narrow absorption lines. Indeed we have found twenty different velocities between -140km/s and -580km/s with many lower levels well elevated above the ground states of numerous ions.

  9. Spatial and temporal variation in evapotranspiration using Raman lidar

    NASA Astrophysics Data System (ADS)

    Eichinger, W. E.; Cooper, D. I.; Hipps, L. E.; Kustas, W. P.; Neale, C. M. U.; Prueger, J. H.

    2006-02-01

    The Los Alamos Raman lidar has been used to make high resolution (25 m) estimates of the evapotranspiration rate over adjacent corn and soybean canopies. The lidar makes three-dimensional measurements of the water vapor content of the atmosphere directly above the canopy that are inverted using Monin-Obukhov similarity theory. This may be used to examine the relationship between evapotranspiration and surface moisture/soil type. Lidar estimates of evapotranspiration reveal a high degree of spatial variability over corn and soybean fields that may be associated with small elevation changes in the area. The spatial structure of the variability is characterized using a structure function and correlation function approach. The power law relationship found by other investigators for soil moisture is not clear in the data for evapotranspiration, nor is the data a straight line over the measured lags. The magnitude of the structure function and the slope changes with time of day, with a probable connection to the amount of evapotranspiration and the spatial variability of the water vapor source. The data used was taken during the soil moisture-atmosphere coupling experiment (SMACEX) conducted in the Walnut Creek Watershed near Ames, Iowa in June and July 2002.

  10. Penman-Monteith Evapotranspiration under Soil Moisture Limiting Conditions across California

    NASA Astrophysics Data System (ADS)

    Purdy, A. J.; Famiglietti, J. S.

    2014-12-01

    In arid and semi-arid regions soil moisture often limits the flux of water to meet the atmospheric evapotranspiration (ET) demand. Potentially drier conditions and more variable precipitation and snow in California create a need to better understand how this reservoir limits ET across the state. The upcoming Soil Moisture Active Passive (SMAP) mission's surface and root zone soil moisture data will provide additional information to force observation based ET models at spatial scales ranging from 3-36 km2. To support application of SMAP data to ET modeling we investigate the role of soil moisture within the Penman-Monteith representation at FLUXNET and agricultural sites across California. We present findings on actual ET under soil moisture limiting conditions that do not violate assumptions within this modeling framework.

  11. Scalar mesons in the decays {eta}' {sup {yields}}3{pi}{sup 0} and {eta}' {sup {yields} {pi}0{pi}+{pi}-}

    SciTech Connect

    Likhoded, A. K. Luchinsky, A. V. Samoylenko, V. D.

    2010-10-15

    The decays {eta} {sup {yields}}3{pi}{sup 0} and {eta} {sup {yields} {pi}0{pi}+{pi}-} are considered within the isobar model. It is shown that, in order to explain the branching ratio and the shape of the Dalitz plot for the decay {eta}' {sup {yields}}3{pi}{sup 0}, it is sufficient to take into account the contributions of the {sigma} and a{sub 0} mesons. The inclusion of the {sigma} meson is necessary for reproducing the shape of the distribution over the Dalitz plot. The branching ratio for the decay {eta}' {sup {yields} {pi}0{pi}+{pi}-} is obtained. The predictions for the distributions over the Dalitz plot for this decay are presented. These predictions depend strongly on model parameters.

  12. 77 FR 2089 - Proposed Information Collection Request of the ETA 204, Experience Rating Report; Comment Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-13

    ..., telephone number (202) 693-2927 (this is not a toll-free number) or by email: dullaghan.edward@dol.gov... different experience rating systems. Used in conjunction with other data, the ETA-204 assists in determining... and Training Administration (ETA). Title: Experience Rating Report. OMB Number: 1205-0164....

  13. 76 FR 27090 - Comment Request for Extension of Information Collection (Without Revisions): Form ETA 9033-A...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-10

    ... Revisions): Form ETA 9033-A, Attestation by Employers Using Alien Crewmembers for Longshore Activities in... collection by Form ETA 9033-A, OMB Control Number 1205-0352, Attestation by Employers Using Alien Crewmembers.... The INA generally prohibits the performance of longshore work by alien crewmembers, however the...

  14. 78 FR 40194 - Proposed Information Collection Request of the ETA 207, Nonmonetary Determination Activities...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-03

    ... Determination Activities Report; Comment Request on Extension Without Change (OMB 1205-0150) AGENCY: Employment....Edward@dol.gov . SUPPLEMENTARY INFORMATION: I. Background The ETA 207 Report, Nonmonetary Determination... concerning the proposed extension collection of the ETA 207, Nonmonetary Determinations Activities...

  15. Observation of eta'c production in gammagamma fusion at CLEO.

    PubMed

    Asner, D M; Dytman, S A; Mehrabyan, S; Mueller, J A; Nam, S; Savinov, V; Huang, G S; Miller, D H; Pavlunin, V; Sanghi, B; Shibata, E I; Shipsey, I P J; Adams, G S; Chasse, M; Cummings, J P; Danko, I; Napolitano, J; Cronin-Hennessy, D; Park, C S; Park, W; Thayer, J B; Thorndike, E H; Coan, T E; Gao, Y S; Liu, F; Stroynowski, R; Artuso, M; Boulahouache, C; Blusk, S; Butt, J; Dambasuren, E; Dorjkhaidav, O; Haynes, J; Menaa, N; Mountain, R; Muramatsu, H; Nandakumar, R; Redjimi, R; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Zhang, Kevin; Mahmood, A H; Csorna, S E; Bonvicini, G; Cinabro, D; Dubrovin, M; Bornheim, A; Lipeles, E; Pappas, S P; Shapiro, A; Weinstein, A J; Mahapatra, R; Nelson, H N; Briere, R A; Chen, G P; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Adam, N E; Alexander, J P; Berkelman, K; Boisvert, V; Cassel, D G; Duboscq, J E; Ecklund, K M; Ehrlich, R; Galik, R S; Gibbons, L; Gittelman, B; Gray, S W; Hartill, D L; Heltsley, B K; Hsu, L; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Magerkurth, A; Mahlke-Krüger, H; Meyer, T O; Patterson, J R; Pedlar, T K; Peterson, D; Pivarski, J; Riley, D; Sadoff, A J; Schwarthoff, H; Shepherd, M R; Sun, W M; Thayer, J G; Urner, D; Wilksen, T; Weinberger, M; Athar, S B; Avery, P; Breva-Newell, L; Potlia, V; Stoeck, H; Yelton, J; Eisenstein, B I; Gollin, G D; Karliner, I; Lowrey, N; Naik, P; Sedlack, C; Selen, M; Thaler, J J; Williams, J; Edwards, K W; Besson, D; Gao, K Y; Gong, D T; Kubota, Y; Li, S Z; Poling, R; Scott, A W; Smith, A; Stepaniak, C J; Urheim, J; Metreveli, Z; Seth, K K; Tomaradze, A; Zweber, P; Arms, K; Eckhart, E; Gan, K K; Gwon, C; Severini, H; Skubic, P

    2004-04-01

    We report on the observation of the eta(')(c)(2(1)S0), the radial excitation of the eta(c)(1(1)S0) ground state of charmonium, in the two-photon fusion reaction gammagamma-->eta(')(c)-->K(0)(S)K+/-pi(-/+) in 13.6 fb(-1) of CLEO II/II.V data and 13.1 fb(-1) of CLEO III data. We obtain M(eta(')(c))=3642.9+/-3.1(stat)+/-1.5(syst) MeV and M(eta(c))=2981.8+/-1.3(stat)+/-1.5(syst) MeV. The corresponding values of hyperfine splittings between 1S0 and 3S1 states are DeltaM(hf)(1S)=115.1+/-2.0 MeV and DeltaM(hf)(2S)=43.1+/-3.4 MeV. Assuming that the eta(c) and eta(')(c) have equal branching fractions to K(S)Kpi, we obtain Gamma(gammagamma)(eta(')(c))=1.3+/-0.6 keV. PMID:15089529

  16. 77 FR 35060 - Employment and Training Administration; Proposed Information Collection Request for the ETA 538...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-12

    ... addresses section below on or before August 13, 2012. ADDRESSES: Submit written comments to Scott Gibbons... toll-free Federal Information Relay Service at 1-877-889-5627 (TTY/TDD). Email: gibbons.scott@dol.gov.... Gibbons. SUPPLEMENTARY INFORMATION: I. Background The ETA 538 and ETA 539 reports are weekly reports...

  17. Cautionary Note on Reporting Eta-Squared Values from Multifactor ANOVA Designs

    ERIC Educational Resources Information Center

    Pierce, Charles A.; Block, Richard A.; Aguinis, Herman

    2004-01-01

    The authors provide a cautionary note on reporting accurate eta-squared values from multifactor analysis of variance (ANOVA) designs. They reinforce the distinction between classical and partial eta-squared as measures of strength of association. They provide examples from articles published in premier psychology journals in which the authors…

  18. USING MM5V3 WITH ETA ANALYSES FOR AIR-QUALITY MODELING AT THE EPA

    EPA Science Inventory

    Efforts have been underway since MM5v3 was released in July 1999 to set up air-quality simulations using Eta analyses as background fields. Our previous simulations used a one-way quadruple-nested set of domains with horizontal grid spacing of 108, 36, 12 and 4 km. With Eta a...

  19. 76 FR 58540 - Proposed Information Collection Request of the ETA 581, Contribution Operations Report; Extension...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-21

    ... Performance System (TPS) which evaluates the employer-related or tax functions of the UI program. The... measuring the performance and effectiveness of states' UI tax operations. Using ETA 581 data, the TPS... report is the only vehicle for collection of information required under the TPS program. If ETA 581...

  20. NOAA Introduces its First-Generation Reference Evapotranspiration Product

    NASA Astrophysics Data System (ADS)

    Hobbins, M.; Geli, H. M.; Lewis, C.; Senay, G. B.; Verdin, J. P.

    2013-12-01

    NOAA is producing daily, gridded operational, long-term, reference evapotranspiration (ETo) data for the National Water Census (NWC). The NWC is a congressional mandate to provide water managers with accurate, up-to-date, scientifically defensible reporting on the national water cycle; as such, it requires a high-quality record of actual ET, which we derive as a fraction of NOAA's land-based ETo a fraction determined by remotely sensed (RS) LST and/or surface reflectance in an operational version of the Simplified Surface Energy Balance (SSEBop). This methodology permits mapping of ET on a routine basis with a high degree of consistency at multiple spatial scales. This presentation addresses the ETo input to this process. NOAA's ETo dataset is generated from the American Society of Civil Engineers Standardized Penman-Monteith equation driven by hourly, 0.125-degree (~12-km) data from the North American Land Data Assimilation System (NLDAS). Coverage is CONUS-wide from Jan 1, 1979, to within five days of the present. The ETo is verified against agro-meteorological stations in western CONUS networks, while a first-order, second-moment uncertainty analysis indicates when, where, and to what extent each driver contributes to ETo variability (and so potentially require the most attention). As the NWC's mandate requires a nationwide coverage, the ETo dataset must also be verified outside of the measure's traditional, agricultural/irrigated areas of application. In this presentation, we summarize the verification of the gridded ETo product and demonstrate the drivers of ETo variability in space and time across CONUS. Beyond its primary use as a component of ET in the NWC, we further explore potential uses of the ETo product as an input to drought models and as a stand-alone index of fast-developing agricultural drought, or 'flash drought.' NOAA's product is the first consistently modeled, daily, continent-wide ETo dataset that is both up-to-date and as temporally

  1. Estimation of Evapotranspiration as a function of Photosynthetic Active Radiation

    NASA Astrophysics Data System (ADS)

    Wesley, E.; Migliaccio, K.; Judge, J.

    2012-12-01

    The purpose of this research project is to more accurately measure the water balance and energy movements to properly allocate water resources at the Snapper Creek Site in Miami-Dade County, FL, by quantifying and estimating evapotranspiration (ET). ET is generally estimated using weather based equations, this project focused on estimating ET as a function of Photosynthetic Active Radiation (PAR). The project objectives were first to compose a function of PAR and calculated coefficients that can accurately estimate daily ET values with the least amount of variables used in its estimation equation, and second, to compare the newly identified ET estimation PAR function to TURC estimations, in comparison to our actual Eddy Covariance (EC) ET data and determine the differences in ET values. PAR, volumetric water content (VWC), and temperature (T) data were quality checked and used in developing singular and multiple variable regression models fit with SigmaPlot software. Fifteen different ET estimation equations were evaluated against EC ET and TURC estimated ET using R2 and slope factors. The selected equation that best estimated EC ET was cross validated using a 5 month data set; its daily and monthly ET values and sums were compared against the commonly used TURC equation. Using a multiple variable regression model, an equation with three variables (i.e., VWC, T, and PAR) was identified that best fit EC ET daily data. However, a regression was also found that used only PAR and provided ET predictions of similar accuracy. The PAR based regression model predicted daily EC ET more accurately than the traditional TURC method. Using only PAR to estimate ET reduces the input variables as compared to using the TURC model which requires T and solar radiation. Thus, not only is the PAR approach more accurate but also more cost effective. The PAR-based ET estimation equation derived in this study may be over fit considering only 5 months of data were used to produce the PAR

  2. Offsetting Streamflow Depletion from Well Pumpage by Capture of Evapotranspiration

    NASA Astrophysics Data System (ADS)

    Konikow, L. F.

    2014-12-01

    It is well established that groundwater pumpage must be balanced by a loss of water elsewhere. This loss comes primarily from storage depletion at early times and increasingly from capture at later times. Capture includes some combination of increases in recharge to the aquifer and decreases in discharge from the aquifer induced by the pumpage. Most capture is manifested as streamflow depletion (e.g., through induced infiltration and/or reductions in baseflow). However, decreasing evapotransirative discharge from an aquifer would constitute a type of capture that does not affect streamflow. In his classic 1940 paper Theis recommends that wells be placed in areas where groundwater "is being lost by evaporation or transpiration by non-productive vegetation," thereby utilizing this "lost" water with a minimal lowering of the water table. This study uses numerical simulation of a hypothetical unconfined stream-aquifer system in an arid climate, where streamflow depletion is typically a major concern, to assess how capture of evapotranspiration (ET) can influence the sources of water for a pumping well when the ET losses are directly affected by spatial and temporal changes in the depth to the water table. Consequently, streamflow depletion for a given pumping rate can be affected by capture of ET and how that varies with well location and the history of development and drawdown. We assume the standard MODFLOW linear model for changes in groundwater ET as the water table declines to a specified extinction depth. In one scenario in which about half the recharge to the aquifer is lost to ET under predevelopment conditions, the percentage of well discharge balanced by decreased ET changed from 1.1% after one year to 18% after 200 years of simulated pumpage. The actual ET rate decreased from 5,372 m3/d under predevelopment conditions to 5,001 m3/d after 200 years of development (a 7% reduction in total ET losses). At this same time, 77% of pumpage is derived from streamflow

  3. A new class of simplified phorbol ester analogues: synthesis and binding to PKC and eta PKC-C1B (eta PKC-CRD2).

    PubMed

    Wender, P A; Kirschberg, T A; Williams, P D; Bastiaans, H M; Irie, K

    1999-10-01

    [formula: see text] A unique class of simplified phorbol ester analogues is described for the first time. A highly efficient retro-annelation sequence was developed in order to remove the five-membered ring from the phorbol diterpene core, allowing access to BCD ring analogues of the phorbol esters. The binding of these analogues to protein kinase C (PKC) and the truncated peptide eta PKC-C1B (eta PKC-CRD2) is also reported. PMID:10825954

  4. Evaporation and reference evapotranspiration trends in Spain

    NASA Astrophysics Data System (ADS)

    Sanchez-Lorenzo, Arturo; Vicente-Serrano, Sergio M.; Wild, Martin; Azorin-Molina, Cesar; Calbó, Josep; Revuelto, Jesús; López-Moreno, Juan I.; Moran-Tejeda, Enrique; Martín-Hernández, Natalia; Peñuelas, Josep

    2015-04-01

    Interest is growing in the trends of atmospheric evaporation demand, increasing the need for long-term time series. In this study, we first describe the development of a dataset on evaporation in Spain based on long-term series of Piché and pan measurement records. Piché measurements have been reported for >50 stations since the 1960s. Measurements of pan evaporation, which is a much more widely studied variable in the literature, are also available, but only since 1984 for 21 stations. Particular emphasis was placed on the homogenization of this dataset (for more details, we refer to Sanchez-Lorenzo et al., 2014, Clim Res, 61: 269-280). Both the mean annual Piché and pan series over Spain showed evaporative increases during the common study period (1985-2011). Furthermore, using the annual Piché records since the 1960s, an evaporation decline was detected from the 1960s to the mid-1980s, which resulted in a non-significant trend over the entire 1961-2011 period. Our results indicate agreement between the decadal variability of reference evapotranspiration (Vicente-Serrano et al., 2014, Glob Planet Chang, 121: 26-40) and surface solar radiation (Sanchez-Lorenzo et al., 2013, Glob Planet Chang, 100: 343-352) and the evaporation from Piché and pan measurements since the mid-1980s, especially during summer. Nevertheless, this agreement needs attention, as Piché evaporimeters are inside meteorological screens and not directly exposed to radiation. Thus, as Piché readings are mainly affected by the aerodynamic term in Penman's evaporation equation and pan records are affected by both the heat balance and aerodynamic terms, the results suggest that both terms must be highly and positively correlated in Spain. In order to check this hypothesis, the radiative and aerodynamic components were estimated using the Penman's equation. The results show that the relationship with the radiative components is weaker than that with the aerodynamic component for both pan and

  5. SECULAR CHANGES IN ETA CARINAE'S WIND 1998-2011

    SciTech Connect

    Mehner, Andrea; Davidson, Kris; Humphreys, Roberta M.; Ishibashi, Kazunori; Martin, John C.; Ruiz, Maria Teresa; Walter, Frederick M.

    2012-05-20

    Stellar wind-emission features in the spectrum of eta Carinae have decreased by factors of 1.5-3 relative to the continuum within the last 10 years. We investigate a large data set from several instruments (STIS, GMOS, UVES) obtained between 1998 and 2011 and analyze the progression of spectral changes in direct view of the star, in the reflected polar-on spectra at FOS4, and at the Weigelt knots. We find that the spectral changes occurred gradually on a timescale of about 10 years and that they are dependent on the viewing angle. The line strengths declined most in our direct view of the star. About a decade ago, broad stellar wind-emission features were much stronger in our line-of-sight view of the star than at FOS4. After the 2009 event, the wind-emission line strengths are now very similar at both locations. High-excitation He I and N II absorption lines in direct view of the star strengthened gradually. The terminal velocity of Balmer P Cyg absorption lines now appears to be less latitude dependent, and the absorption strength may have weakened at FOS4. Latitude-dependent alterations in the mass-loss rate and the ionization structure of eta Carinae's wind are likely explanations for the observed spectral changes.

  6. Effects of water salinity on the correlation scale of Root density and Evapotranspiration fluxes

    NASA Astrophysics Data System (ADS)

    Ajeel, Ali; Saeed, Ali; Dragonetti, Giovanna; Comegna, Alessandro; Lamaddalena, Nicola; Coppola, Antonio

    2015-04-01

    Spatial pattern and the correlation of different soil and plant parameters were examined in a green bean field experiment carried out at the Mediterranean Agronomic Institute of Bari, Italy. The experiment aimed to evaluate the role of local processes of salt accumulation and transport which mainly influences the evapotranspiration (and thus the root uptake) processes under different water salinity levels. The experiment consisted of three transects of 30m length and 4.2 m width, irrigated with three different salinity levels (1dSm-1, 3dSm-1, 6dSm-1). Soil measurements (electrical conductivity and soil water content) were monitored along transects in 24 sites, 1 m apart by using TDR probes and Diviner 2000. Water storage measured by TDR and Diviner sensor were coupled for calculating directly the evapotranspiration fluxes along the whole soil profile under the different salinity levels imposed during the experiment. In the same sites, crop monitoring involved measurements of Leaf Area Index (LAI), Osmotic Potential (OP), Leaf Water Potential (LWP), and Root length Density (RlD). Soil and plant properties were analyzed by classical statistics, geostatistics methods and spectral analysis. Results indicated moderate to large spatial variability across the field for soil and plant parameters under all salinity treatments. Furthermore, cross-semivariograms exhibited a strong positive spatial interdependence between electrical conductivity of soil solution ECw with ET and RlD in transect treated with 3dSm-1 as well as with LAI in transect treated with 6dSm-1 at all 24 monitoring sites. Spectral analysis enabled to identify the observation window to sample the soil salinity information responsible for a given plant response (ET, OP, RlD). It is also allowed a clear identification of the spatial scale at which the soil water salinity level and distribution and the crop response in terms of actual evapotranspiration ET, RlD and OP, are actually correlated. Additionally

  7. Recurrent X-ray Emission Variations of Eta Carinae and the Binary Hypothesis

    NASA Technical Reports Server (NTRS)

    Ishibashi, K.; Corcoran, M. F.; Davidson, K.; Swank, J. H.; Petre, R.; Drake, S. A.; Damineki, A.; White, S.

    1998-01-01

    Recent studies suggest that, the super-massive star eta Carinae may have a massive stellar companion (Damineli, Conti, and Lopes 1997), although the dense ejecta surrounding the star make this claim hard to test using conventional methods. Settling this question is critical for determining the current evolutionary state and future evolution of the star. We address this problem by an unconventional method: If eta Carinae is a binary, X-ray emission should be produced in shock waves generated by wind-wind collisions in the region between eta Carinae and its companion. Detailed X-ray monitoring of eta Carinae for more that) 2 years shows that the observed emission generally resembles colliding-wind X-ray emission, but with some significant discrepancies. Furthermore, periodic X-ray "flaring" may provide an additional clue to determine the presence of a companion star and for atmospheric pulsation in eta Carinae.

  8. Near-Field ETAS Constraints and Applications to Seismic Hazard Assessment

    NASA Astrophysics Data System (ADS)

    Yoder, Mark R.; Rundle, John B.; Glasscoe, Margaret T.

    2015-08-01

    The epidemic type aftershock sequence (ETAS) statistical model of aftershock seismicity combines various earthquake scaling relations to produce synthetic earthquake catalogs, or estimates of aftershock seismicity rates, based on recent earthquake activity. One challenge to ETAS-based hazard assessment is the large number of free parameters involved. In this paper, we introduce an approach to constrain this parameter space from canonical scaling relations, empirical observations, and fundamental physics. We show that ETAS parameters can be estimated as a function of an earthquake's magnitude m based on the finite temporal and spatial extents of the rupture area. This approach facilitates fast ETAS-based estimates of seismicity from large "seed" catalogs, and it is particularly well suited to web-based deployment and otherwise automated implementations. It constitutes a significant improvement over contemporary ETAS by mitigating variability related to instrumentation and subjective catalog selection.

  9. Lewis acid adducts (BH sub 3 , Me sup + , and Et sup + ) of the. eta. sup 4 and. eta. sup 2 isomers of Cp sup * Ir(thiophene)

    SciTech Connect

    Chen, Jiabi; Angelici, R.J. )

    1990-03-01

    The {eta}{sup 4}-thiophene complex Cp{sup *}Ir({eta}{sup 4}-2,5-Me{sub 2}T) (2), where 2,5-Me{sub 2} is 2,5-dimethylthiophene, reacts with Me{sub 2}S{center dot}BH{sub 3} to give the BH{sub 3} adduct Cp{sup *}Ir({eta}{sup 4}-2,5-Me{sub 2}T{center dot}BH{sub 3}) (6), demonstrating the unusually high basicity of the sulfur in 2 as compared with that in Me{sub 2}S. Basic amines remove the BH{sub 3} in 6 to give 2. Surprisingly, the isomer Cp{sup *}Ir({eta}{sup 2}-2,5-Me{sub 2}T) (4) also reacts with Me{sub 2}S{center dot}BH to give 6. The 2-methylthiophene analogues of 2 and 4 react similarly to give Cp{sup *}Ir({eta}{sup 4}-2-MeT{center dot}BH{sub 3}) (5), whose structure was determined by X-ray diffraction. Complex 2 also reacts with R{sub 3}O{sup +} (R = Me, Et) to give the S-alkylated thiophene complexes Cp{sup *}Ir({eta}{sup 4}-2,5-Me{sub 2}T-R){sup +}.

  10. Investigation of near-threshold eta-meson production in the reaction {pi}{sup -}p{yields} {eta}n

    SciTech Connect

    Bayadilov, D. E.; Beloglazov, Yu. A.; Gridnev, A. B.; Kozlenko, N. G.; Kruglov, S. P.; Kulbardis, A. A.; Lopatin, I. V.; Novinskiy, D. V.; Radkov, A. K.; Sumachev, V. V.; Filimonov, E. A.; Shvedchikov, A. V.

    2012-08-15

    Differential and total cross sections for eta-meson production in the reaction {pi}{sup -}p {yields} {eta}n were measured within the experimental program eta-meson physics implemented in the pion channel of the synchrocyclotron of the Petersburg Nuclear Physics Institute (PNPI, Gatchina). These measurements were performed at incident-pion momenta (700, 710, 720, and 730 MeV/c) in the vicinity of the threshold for the process under study by using the neutral-meson spectrometer designed and created at the Meson Physics Laboratory of PNPI. It is shown that, in the immediate vicinity of the threshold (685 MeV/c), the process of eta-meson production proceeds predominantly via S{sub 11}(1535)-resonance formation followed by the decay S{sub 11}(1535) {yields} {eta}n (the respective branching fraction is Br Almost-Equal-To 60%), but that, as the momentum of incident pions increases, the role of the D wave becomes ever more important. A detailed analysis of this effect indicates that it is due to the increasing contribution of the D{sub 13}(1520) resonance. Although the branching fraction of the decay of this resonance through the {eta}n channel is assumed to be very small (BR Almost-Equal-To 0.24%), the effect is enhanced owing to the interference between the D wave and the dominant resonance S{sub 11}(1535).

  11. Regional evaluation of evapotranspiration in the Everglades

    USGS Publications Warehouse

    German, E.R.

    2000-01-01

    Nine sites in the Florida Everglades were selected and instrumented for collection of data necessary for evapotranspiration-determination using the Bowen-ratio energy-budget method. The sites were selected to represent the sawgrass or cattail marshes, wet prairie, and open-water areas that constitute most of the natural Everglades system. At each site, measurements necessary for evapotranspiration (ET) calculation and modeling were automatically made and stored on-site at 15- or 30-minute intervals. Data collected included air temperature and humidity at two heights, wind speed and direction, incoming solar radiation, net solar radiation, water level and temperature, soil moisture content, soil temperature, soil heat flux, and rainfall. Data summarized in this report were collected from January 1996 through December 1997, and the development of site-specific and regional models of ET for this period is described. Latent heat flux is the energy flux density equivalent of the ET rate. Modified Priestley-Taylor models of latent heat flux as a function of selected independent variables were developed at each site. These models were used to fill in periods of missing latent heat flux measurement, and to develop regional models of the entire Everglades region. The regional models may be used to estimate ET in wet prairie, sawgrass or cattail marsh, and open-water portions of the natural Everglades system. The models are not applicable to forested areas or to the brackish areas adjacent to Florida Bay. Two types of regional models were developed. One type of model uses measurements of available energy at a site, together with incoming solar energy and water depth, to estimate hourly ET. This available-energy model requires site data for net radiation, water heat storage, and soil heat flux, as well as data for incoming solar radiation and water depth. The other type of model requires only incoming solar energy, air temperature, and water depth data to provide estimates of

  12. Assessing reference evapotranspiration in a subhumid climate in NE Austria

    NASA Astrophysics Data System (ADS)

    Nolz, Reinhard; Eitzinger, Josef; Cepuder, Peter

    2015-04-01

    Computing reference evapotranspiration and multiplying it with a specific crop coefficient as recommended by the Food and Agriculture Organization of the United Nations (FAO) is the most widely accepted approach to estimate plant water requirements. The standardized form of the well-known FAO Penman-Monteith equation, published by the Environmental and Water Resources Institute of the American Society of Civil Engineers (ASCE-EWRI), is recommended as a standard procedure for calculating reference evapotranspiration. Applied and validated under different climatic conditions it generally achieved good results compared to other methods. However, several studies documented deviations between measured and calculated reference evapotranspiration depending on local environmental conditions. Consequently, it seems advisable to evaluate the model under local environmental conditions. Evapotranspiration was determined at a subhumid site in Austria (48°12'N, 16°34'E; 157 m asl) using a large weighing lysimeter operated at (limited) reference conditions and compared with calculations according to ASCE-EWRI. The lysimeter had an inner diameter of 1.9 m and a hemispherical bottom with a maximum depth of 2.5 m. Seepage water was measured at a free draining outlet using a tipping bucket. Lysimeter mass changes were sensed by a weighing facility with an accuracy of ±0.1 mm. Both rainfall and evapotranspiration were determined directly from lysimeter data using a simple water balance equation. Meteorological data for the ASCE-EWRI model were obtained from a weather station of the Central Institute for Meteorology and Geodynamics, Austria (ZAMG). The study period was from 2005 to 2010, analyses were based upon daily time steps. Daily calculated reference evapotranspiration was generally overestimated at small values, whereas it was rather underestimated when evapotranspiration was large, which is supported also by other studies. In the given case, advection of sensible heat proved

  13. Influence of land-surface evapotranspiration on the earth's climate

    NASA Technical Reports Server (NTRS)

    Shukla, J.; Mintz, Y.

    1982-01-01

    Land-surface evapotranspiration is shown to strongly influence global fields of rainfall, temperature and motion by calculations using a numerical model of the atmosphere, confirming the general belief in the importance of evapotranspiration-producing surface vegetation for the earth's climate. The current version of the Goddard Laboratory atmospheric general circulation model is used in the present experiment, in which conservation equations for mass, momentum, moisture and energy are expressed in finite-difference form for a spherical grid to calculate (1) surface pressure field evolution, and (2) the wind, temperature, and water vapor fields at nine levels between the surface and a 20 km height.

  14. Drought impacts and resilience on crops via evapotranspiration estimations

    NASA Astrophysics Data System (ADS)

    Timmermans, Joris; Asadollahi Dolatabad, Saeid

    2015-04-01

    Currently, the global needs for food and water is at a critical level. It has been estimated that 12.5 % of the global population suffers from malnutrition and 768 million people still do not have access to clean drinking water. This need is increasing because of population growth but also by climate change. Changes in precipitation patterns will result either in flooding or droughts. Consequently availability, usability and affordability of water is becoming challenge and efficient use of water and water management is becoming more important, particularly during severe drought events. Drought monitoring for agricultural purposes is very hard. While meteorological drought can accurately be monitored using precipitation only, estimating agricultural drought is more difficult. This is because agricultural drought is dependent on the meteorological drought, the impacts on the vegetation, and the resilience of the crops. As such not only precipitation estimates are required but also evapotranspiration at plant/plot scale. Evapotranspiration (ET) describes the amount of water evaporated from soil and vegetation. As 65% of precipitation is lost by ET, drought severity is highly linked with this variable. In drought research, the precise quantification of ET and its spatio-temporal variability is therefore essential. In this view, remote sensing based models to estimate ET, such as SEBAL and SEBS, are of high value. However the resolution of current evapotranspiration products are not good enough for monitoring the impact of the droughts on the specific crops. This limitation originates because plot scales are in general smaller than the resolution of the available satellite ET products. As such remote sensing estimates of evapotranspiration are always a combination of different land surface types and cannot be used for plant health and drought resilience studies. The goal of this research is therefore to enable adequate resolutions of daily evapotranspiration estimates

  15. Heterogeneous terrain: a challenge to derive evapotranspiration with remote sensing and scintillometry

    NASA Astrophysics Data System (ADS)

    Thiem, Christina; Sun, Liya; Müller, Benjamin; Bernhardt, Matthias; Schulz, Karsten

    2014-05-01

    Despite the importance of evapotranspiration for Meteorology, Hydrology and Agronomy, obtaining area-averaged evapotranspiration estimates is cost as well as maintenance intensive: usually area-averaged evapotranspiration estimates are obtained by distributed sensor networks or remotely sensed with a scintillometer. A low cost alternative for evapotranspiration estimates are satellite images, as many of them are freely available. This approach has been proven to be worthwhile above homogeneous terrain, and typically evapotranspiration data obtained with scintillometry are applied for validation. We will extend this approach to heterogeneous terrain: evapotranspiration estimates from ASTER 2013 images will be compared to scintillometer derived evapotranspiration estimates. The goodness of the correlation will be presented as well as an uncertainty estimation for both the ASTER derived and the scintillometer derived evapotranspiration.

  16. Sub-canopy evapotranspiration from floating vegetation and open water in a swamp forest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous studies have demonstrated large discrepancies in the difference between evapotranspiration from wetland vegetation and evaporation from open water. In this study, we investigate evapotranspiration differences between water and vegetation in a scenario that has otherwise not been extensively...

  17. Constraints on Decreases in Eta Carinae's Mass-loss from 3D Hydrodynamic Simulations of Its Binary Colliding Winds

    NASA Technical Reports Server (NTRS)

    Madura, T. I.; Gull, T. R.; Okazaki, A. T.; Russell, C. M. P.; Owocki, S. P.; Groh, J. H.; Corcoran, M. F.; Hamaguchi, K.; Teodoro, M.

    2013-01-01

    Recent work suggests that the mass-loss rate of the primary star Eta-A in the massive colliding wind binary Eta Carinae dropped by a factor of 2-3 between 1999 and 2010. We present result from large- (+/- 1545 au) and small- (+/- 155 au) domain, 3D smoothed particle hydrodynamics (SPH) simulations of Eta Car's colliding winds for three Eta-A mass-loss rates ( (dot-M(sub Eta-A) = 2.4, 4.8 and 8.5 × 10(exp -4) M(solar)/ yr), investigating the effects on the dynamics of the binary wind-wind collision (WWC). These simulations include orbital motion, optically thin radiative cooling and radiative forces. We find that dot-M Eta-A greatly affects the time-dependent hydrodynamics at all spatial scales investigated. The simulations also show that the post-shock wind of the companion star Eta-B switches from the adiabatic to the radiative-cooling regime during periastron passage (Phi approx.= 0.985-1.02). This switchover starts later and ends earlier the lower the value of dot-M Eta-A and is caused by the encroachment of the wind of Eta-A into the acceleration zone of Eta-B's wind, plus radiative inhibition of Eta-B's wind by Eta-A. The SPH simulations together with 1D radiative transfer models of Eta-A's spectra reveal that a factor of 2 or more drop in dot-M EtaA should lead to substantial changes in numerous multiwavelength observables. Recent observations are not fully consistent with the model predictions, indicating that any drop in dot- M Eta-A was likely by a factor of approx. < 2 and occurred after 2004. We speculate that most of the recent observed changes in Eta Car are due to a small increase in the WWC opening angle that produces significant effects because our line of sight to the system lies close to the dense walls of the WWC zone. A modest decrease in dot-M Eta-A may be responsible, but changes in the wind/stellar parameter of Eta-B, while less likely, cannot yet be fully ruled out. We suggest observations during Eta-Car's next periastron in 2014 to further

  18. Evapotranspiration from areas of native vegetation in west-central Florida

    USGS Publications Warehouse

    Bidlake, W.R.; Woodham, W.M.; Lopez, Miguel Angel

    1996-01-01

    The micrometeorological methods of energy-balance Bowen ratio and eddy correlation probably are suitable for determining evapotranspiration from unforested sites, but the aerodynamic effects of tall tree canopies need to be considered when the methods are used for forested sites. Potential evapotranspiration methods might not yield reliable estimates of evapotranspiration for all areas of native vegetation. Estimates of annual evapotranspiration ranged from 970 millimeters for a cypress swamp site to 1,060 millimeters for a pine flatwood site.

  19. The actual goals of geoethics

    NASA Astrophysics Data System (ADS)

    Nemec, Vaclav

    2014-05-01

    The most actual goals of geoethics have been formulated as results of the International Conference on Geoethics (October 2013) held at the geoethics birth-place Pribram (Czech Republic): In the sphere of education and public enlightenment an appropriate needed minimum know how of Earth sciences should be intensively promoted together with cultivating ethical way of thinking and acting for the sustainable well-being of the society. The actual activities of the Intergovernmental Panel of Climate Changes are not sustainable with the existing knowledge of the Earth sciences (as presented in the results of the 33rd and 34th International Geological Congresses). This knowledge should be incorporated into any further work of the IPCC. In the sphere of legislation in a large international co-operation following steps are needed: - to re-formulate the term of a "false alarm" and its legal consequences, - to demand very consequently the needed evaluation of existing risks, - to solve problems of rights of individuals and minorities in cases of the optimum use of mineral resources and of the optimum protection of the local population against emergency dangers and disasters; common good (well-being) must be considered as the priority when solving ethical dilemmas. The precaution principle should be applied in any decision making process. Earth scientists presenting their expert opinions are not exempted from civil, administrative or even criminal liabilities. Details must be established by national law and jurisprudence. The well known case of the L'Aquila earthquake (2009) should serve as a serious warning because of the proven misuse of geoethics for protecting top Italian seismologists responsible and sentenced for their inadequate superficial behaviour causing lot of human victims. Another recent scandal with the Himalayan fossil fraud will be also documented. A support is needed for any effort to analyze and to disclose the problems of the deformation of the contemporary

  20. Operational evapotranspiration based on Earth observation satellites

    NASA Astrophysics Data System (ADS)

    Gellens-Meulenberghs, Françoise; Ghilain, Nicolas; Arboleda, Alirio; Barrios, Jose-Miguel

    2016-04-01

    Geostationary satellites have the potential to follow fast evolving atmospheric and Earth surface phenomena such those related to cloud cover evolution and diurnal cycle. Since about 15 years, EUMETSAT has set up a network named 'Satellite Application Facility' (SAF, http://www.eumetsat.int/website/home/Satellites/GroundSegment/Safs/index.html) to complement its ground segment. The Land Surface Analysis (LSA) SAF (http://landsaf.meteo.pt/) is devoted to the development of operational products derived from the European meteorological satellites. In particular, an evapotranspiration (ET) product has been developed by the Royal Meteorological Institute of Belgium. Instantaneous and daily integrated results are produced in near real time and are freely available respectively since the end of 2009 and 2010. The products cover Europe, Africa and the Eastern part of South America with the spatial resolution of the SEVIRI sensor on-board Meteosat Second Generation (MSG) satellites. The ET product algorithm (Ghilain et al., 2011) is based on a simplified Soil-Vegetation-Atmosphere transfer (SVAT) scheme, forced with MSG derived radiative products (LSA SAF short and longwave surface fluxes, albedo). It has been extensively validated against in-situ validation data, mainly FLUXNET observations, demonstrating its good performances except in some arid or semi-arid areas. Research has then been pursued to develop an improved version for those areas. Solutions have been found in reviewing some of the model parameterizations and in assimilating additional satellite products (mainly vegetation indices and land surface temperature) into the model. The ET products will be complemented with related latent and sensible heat fluxes, to allow the monitoring of land surface energy partitioning. The new algorithm version should be tested in the LSA-SAF operational computer system in 2016 and results should become accessible to beta-users/regular users by the end of 2016/early 2017. In

  1. A Measurement of the B ---> Eta/C K Branching Fraction Using the BaBar Detector

    SciTech Connect

    Jackson, Frank; /Manchester U.

    2006-04-26

    The branching fraction is measured for the decay channels B{sup 0} {yields} {eta}{sub c}K{sub S}{sup 0} and B{sup +} {yields} {eta}{sub c}K{sup +} where {eta}{sub c} {yields} K{bar K}{pi}, using the BABAR detector. The {eta}{sub c} {yields} K{sub S}{sup 0}K{sup +}{pi}{sup -} and {eta}{sub c} {yields} K{sup +}K{sup -}{pi}{sup 0} decay channels are used, including non-resonant decays and possibly those through intermediate resonances.

  2. Evapotranspiration: Mass balance measurements compared with flux estimation methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration (ET) may be measured by mass balance methods and estimated by flux sensing methods. The mass balance methods are typically restricted in terms of the area that can be represented (e.g., surface area of weighing lysimeter (LYS) or equivalent representative area of neutron probe (NP...

  3. FIELD EVALUATION OF EVAPO-TRANSPIRATION (ET) CAPS

    EPA Science Inventory

    A field study was conducted to assess the ability of landfill covers to control percolation into the waste. Performance of one conventional cover was compared to that of two evapotranspiration (ET) tree covers, using large (7 x 14 m) lined lysimeters at the Leon County Solid W...

  4. Ecosystem evapotranspiration: Challenges in measurements, estimates, and modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration (ET) processes at the leaf-to-landscape scales in multiple land uses have important controls and feedbacks for the local, regional and global climate and water resource systems. Innovative methods, tools, and technologies for improved understanding and quantification of ET and cro...

  5. Using Thermal Remote Sensing for Drought and Evapotranspiration Monitoring

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal infrared (TIR) remote sensing of land-surface temperature (LST) provides valuable information about the sub-surface moisture status affecting evapotranspiration and detecting the onset and severity of drought. While empirical indices measuring anomalies in LST and vegetation amount (e.g., as...

  6. Using Thermal Remote Sensing for Drought and Evapotranspiration Monitoring

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal infrared (TIR) remote sensing of land-surface temperature (LST) provides valuable information about the sub-surface moisture status for estimating evapotranspiration and detecting the onset and severity of drought. While empirical indices measuring anomalies in LST and vegetation amount (e.g...

  7. Seasonal energy and evapotranspiration partitioning in a desert vineyard

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The challenge of partitioning energy and evapotranspiration (ET) components was addressed over a season (bud break till harvest) in a wine grape vineyard located in an extreme arid region. A below canopy energy balance approach was applied to continuously estimate evaporation from the soil (E) while...

  8. Partitioning evapotranspiration into evaporation and transpiration in a corn field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration (ET) is a main component of the hydrology cycle. It consists of soil water evaporation (E) and plant transpiration (T). Accurate partitioning of ET into E and T is challenging. We measured soil water E using heat pulse sensors and a micro-Bowen ratio system, T using stem flow gaug...

  9. 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...

  10. Evapotranspiration: Progress in measurement and modeling in agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As the water resources available for agriculture become limiting due to population growth, competition from other water users, drought and water quality degradation, the importance of evapotranspiration (ET) as a major component of water use in agriculture grows. This paper provides a focused survey...

  11. Deriving hourly evapotranspiration (ET) rates with SEBS: A lysimetric evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous energy balance (EB) algorithms have been developed to use remote sensing data for mapping evapotranspiration (ET) on a regional basis. Adopting any single or combination of these models for an operational ET remote sensing program requires a thorough evaluation. The Surface Energy Balance S...

  12. Estimation of evapotranspiration rate in irrigated lands using stable isotopes

    NASA Astrophysics Data System (ADS)

    Umirzakov, Gulomjon; Windhorst, David; Forkutsa, Irina; Brauer, Lutz; Frede, Hans-Georg

    2013-04-01

    Agriculture in the Aral Sea basin is the main consumer of water resources and due to the current agricultural management practices inefficient water usage causes huge losses of freshwater resources. There is huge potential to save water resources in order to reach a more efficient water use in irrigated areas. Therefore, research is required to reveal the mechanisms of hydrological fluxes in irrigated areas. This paper focuses on estimation of evapotranspiration which is one of the crucial components in the water balance of irrigated lands. Our main objective is to estimate the rate of evapotranspiration on irrigated lands and partitioning of evaporation into transpiration using stable isotopes measurements. Experiments has done in 2 different soil types (sandy and sandy loam) irrigated areas in Ferghana Valley (Uzbekistan). Soil samples were collected during the vegetation period. The soil water from these samples was extracted via a cryogenic extraction method and analyzed for the isotopic ratio of the water isotopes (2H and 18O) based on a laser spectroscopy method (DLT 100, Los Gatos USA). Evapotranspiration rates were estimated with Isotope Mass Balance method. The results of evapotranspiration obtained using isotope mass balance method is compared with the results of Catchment Modeling Framework -1D model results which has done in the same area and the same time.

  13. Bushland Evapotranspiration and Agricultural Remote Sensing EXperiment 2007 (BEAREX07)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Texas High Plains, every millimeter of irrigation water saved greatly affects profit margins. If available, high-resolution daily evapotranspiration (ET) maps would help producers plan their irrigation schedule effectively. The ET maps derived from satellite sensors with daily coverage such a...

  14. ADVECTION INFLUENCES ON EVAPOTRANSPIRATION OF ALFALFA IN A SEMIARID ENVIRONMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advective enhancement of crop evapotranspiration (ET) occurs when drier, hotter air is transported into the crop by wind and can be an important factor in the water balance of irrigated crops in a semiarid climate. Thirteen days of moderate to extremely high ET rates of irrigated alfalfa (Medicago ...

  15. Bushland evapotranspiration and agricultural remote sensing system (BEARS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High-resolution daily evapotranspiration (ET) maps would greatly assist irrigation scheduling and hydrologic modeling. Numerous remote sensing-based ET algorithms that vary in complexity are available for estimating spatially and temporally variable daily ET at a regional scale. However, implementat...

  16. Experimental verification of a recursive method to calculate evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recently, a recursive combination method (RCM) to calculate potential and crop evapotranspiration (ET) was given by Lascano and Van Bavel (Agron. J. 2007, 99:585–590). The RCM differs from the Penman-Monteith (PM) method, the main difference being that the assumptions made regarding the temperature ...

  17. A field test of recursive calculation of crop evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous methods to calculate the evapotranspiration (ET) rate from field crops have been proposed, but few have convincingly demonstrated to be usefully accurate. The direct measurement of ET requires weighable lysimeters. However, the use of a surface energy balance to calculate ET requires a corr...

  18. Evapotranspiration model of different complexity for multiple land cover types

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A comparison between half-hourly and daily measured and computed evapotranspiration (ET) using three models of different complexity, namely the Priestley-Taylor (P-T), reference Penman-Monteith (P-M), and Common Land Model (CLM) was conducted using three AmeriFlux sites under different land cover an...

  19. Remote sensing estimation of evapotranspiration for SWAT Model Calibration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrological models are used to assess many water resource problems from water quantity to water quality issues. The accurate assessment of the water budget, primarily the influence of precipitation and evapotranspiration (ET), is a critical first-step evaluation, which is often overlooked in hydro...

  20. Crop coefficient development and application to an evapotranspiration network

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop coefficients derived from properly designed, operated, and maintained lysimeters provide the most accurate values throughout the growing season and are critical in the computation of hourly and daily,regionally based, crop evapotranspiration (ET) values. Multi-stage crop coefficients can be der...

  1. ESTIMATION OF POTENTIAL EVAPOTRANSPIRATION FROM MERGED CERES and MODIS OBSERVATIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate and timely estimates of potential evapotranspiration (ET) and knowledge of their spatial and temporal distribution are essential for agriculture and water resource management as well as for understanding the impacts of climate variability on terrestrial systems. Because of the paucity and i...

  2. EVAPOTRANSPIRATION OVER A CAMELINA CROP AT MARICOPA, ARIZONA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration (ET) over an oilseed crop, Camelina sativa, was evaluated for an experimental plot in Maricopa, Arizona between December 2006 and April 2007. Camelina (cv. Robinson) was grown in a 1.1 ha field in a randomized design containing 32 plots replicated for 4 levels of water depletion: ...

  3. Daily time series evapotranspiration maps for Oklahoma and Texas panhandle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration (ET) is an important process in ecosystems’ water budget and closely linked to its productivity. Therefore, regional scale daily time series ET maps developed at high and medium resolutions have large utility in studying the carbon-energy-water nexus and managing water resources. ...

  4. GOES Solar Radiation for Evapotranspiration Estimation and Streamflow Predictions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Weather Service River Forecast System uses the Sacramento Soil Moisture Accounting (SAC-SMA) rainfall-runoff model to produce daily river and flood forecasts and issue flood warnings. The manual observations of total sky cover used to estimate solar radiation and potential evapotranspir...

  5. Calculation of canopy resistance with a recursive evapotranspiration model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The calculation of hourly and daily crop evapotranspiration (ETc) from weather variables requires a corresponding hourly or daily value of canopy resistance (rc). An iterative method first proposed by MI Budyko to calculate ETc finds the surface canopy temperature (Ts) that satisfies the crop’s ener...

  6. Determining the oxygen isotope composition of evapotranspiration with eddy covariance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The oxygen isotope componsition of evapotranspiration (dF) represents an important tracer in the study of biosphere-atmosphere interactions, hydrology, paleoclimate, and carbon cycling. Here we demonstrate direct measurement of dF based on eddy covariance (EC) and tunable diode laser (EC-TDL) techni...

  7. Constraining the polarization of the proton's glue with the eta meson

    NASA Astrophysics Data System (ADS)

    Seele, Joseph

    The division of the proton's spin among its quarks and gluons is a fundamental question in modern nuclear physics. The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) is measuring asymmetries in polarized proton-proton collisions at s = 200 GeV to garner information about the polarizations of the quarks and gluons. Measurements of the double helicity asymmetry for high pT mid-rapidity eta meson production in proton-proton collisions at s = 200 GeV are presented in this work. In order to obtain information about the polarizations of the quarks and gluons in the proton using the eta meson, the eta meson fragmentation functions must be known. No set existed, therefore a first global fit to the eta meson fragmentation functions was performed. The fit benefits from the inclusion of measurements of the cross section for eta meson production in proton-proton collisions. Therefore, a measurement of the cross section for high pT mid-rapidity eta meson production in proton-proton collisions at s = 200 GeV is performed to aid the fit. With the eta fragmentation functions, the measurement of the double helicity asymmetry is used to constrain the contribution of the spins of the gluons to the spin of the proton. Using a model and the work in this thesis, an estimate of the gluon contribution to the proton's spin is calculated and compared to other evaluations.

  8. Measurement of the branching fraction for $\\tau\\to\\eta K\

    SciTech Connect

    del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Indian Inst. Tech., Guwahati /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Paris U., VI-VII /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

    2011-08-12

    The authors report on analyses of tau lepton decays {tau}{sup -} {yields} {eta}K{sup -}{nu}{sub {tau}} and {tau}{sup -} {yields} {eta}{pi}{sup -}{nu}{sub {tau}}, with {eta} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0}, using 470 fb{sup -1} of data from the BABAR experiment at PEP-II, collected at center-of-mass energies at and near the {Upsilon}(4S) resonance. They measure the branching fraction for the {tau}{sup -} {yields} {eta}K{sup -}{nu}{sub {tau}} decay mode, {Beta}({tau}{sup -} {yields} {eta}K{sup -}{nu}{sub {tau}}) = (1.42 {+-} 0.11(stat) {+-} 0.07(syst)) x 10{sup -4}, and report a 95% confidence level upper limit for the second-class current process {tau}{sup -} {yields} {eta}{pi}{sup -}{nu}{sub {tau}}, {Beta}({tau}{sup -} {yields} {eta}{pi}{sup -}{nu}{sub {tau}}) < 9.9 x 10{sup -5}.

  9. UNEXPECTED IONIZATION STRUCTURE IN ETA CARINAE'S ''WEIGELT KNOTS''

    SciTech Connect

    Remmen, Grant N.; Davidson, Kris; Mehner, Andrea

    2013-08-10

    The Weigelt knots, dense slow-moving ejecta near {eta} Carinae, are mysterious in structure as well as in origin. Using spatially dithered spectrograms obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS), we have partially resolved the ionization zones of one knot. Contrary to simple models, higher ionization levels occur on the outer side, i.e., farther from the star. They cannot represent a bow shock, and no satisfying explanation is yet available-though we sketch one qualitative possibility. STIS spectrograms provide far more reliable spatial measurements of the Weigelt knots than HST images do, and this technique can also be applied to the knots' proper motion problem. Our spatial measurement accuracy is about 10 mas, corresponding to a projected linear scale of the order of 30 AU, which is appreciably smaller than the size of each Weigelt knot.

  10. The -145 km/S Absorption System of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Vieira, G.; Gull, T. R.; Danks, A.; Johansson, S.

    2002-01-01

    With the STIS E230H mode (R-118,000) , we have identified about twenty absorption components in line of sight from Eta Carinae. Two components, one at -513 km/s and another at -145 W s , are quite different in character from the others, mostly at intermediate velocities. The -145 km/s component is significantly wider in fwhm, is seen in many more species, and the lower level can be above 20,000/cm, well above the 2000/cm noted in the -513 km/s component. In the spectral region from 2400 to 3160A, approximately 500 absorption lines have been identified. In this poster, we will present line identifications and atomic parameters of the measured lines, hopefully providing insight as to what levels are being excited and by what processes.

  11. Recovery from a Giant Eruption: The Case of Eta Car

    NASA Astrophysics Data System (ADS)

    Davidson, Kris; Mehner, Andrea; Martin, John C.; Humphreys, Roberta M.

    2016-01-01

    Giant eruptions or SN Impostors are far more mysterious than "real" supernovae, because they are scarcer and because they have received far less theoretical effort. One rather special problem is the disequilibrium state of the post-eruption object. It may be partially observable by watching the star's gradual recovery; which, in principle, may offer clues to the basic instability mechanisms. So far, the only example that can be observed well enough is eta Carinae. This object's history offers tantalizing clues and counter-clues. For instance: (1) Before 2000, the recovery timescale seemed to be of order 150 years; but (2) around 2000, many attributes began to change much more rapidly; and (3) the 150-year recovery process has been punctuated by about three abrupt changes of state. This strange combination of facts has received almost no theoretical attention.

  12. Understanding the X-ray Flaring from Eta Carinae

    NASA Technical Reports Server (NTRS)

    Moffat, A.F.J.; Corcoran, Michael F.

    2009-01-01

    We quantify the rapid variations in X-ray brightness ("flares") from the extremely massive colliding wind binary Eta Carinae seen during the past three orbital cycles by RXTE. The observed flares tend to be shorter in duration and more frequent as periastron is approached, although the largest ones tend to be roughly constant in strength at all phases. Plausible scenarios include (1) the largest of multi-scale stochastic wind clumps from the LBV component entering and compressing the hard X-ray emitting wind-wind collision (WWC) zone, (2) large-scale corotating interacting regions in the LBV wind sweeping across the WWC zone, or (3) instabilities intrinsic to the WWC zone. The first one appears to be most consistent with the observations, requiring homologously expanding clumps as they propagate outward in the LBV wind and a turbulence-like powerlaw distribution of clumps, decreasing in number towards larger sizes, as seen in Wolf-Rayet winds.

  13. The Ejecta of Eta Carinae as Studied by STIS

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Oegerle, William R. (Technical Monitor)

    2002-01-01

    The Space Telescope Imaging Spectrograph has been used to study the emission and absorption spectra of ejecta surrounding Eta Carinae. Discussion will be presented on the overall structure of the Homunculus, the Weigelt blobs and the Strontium filament. Three visits have been accomplished with the Position Angle precisely the same and covering the Central Source and Weigelt Blobs B and D. Deep spectra have been done at several positions to obtain the overall velocity structure of the Homunculus and the disk region. Mapping has been done with the STIS medium dispersion gratings set near H beta and H alpha. We have obtained full coverage of the strontium filament from 1640 Angstroms to 10300 Angstroms. The structure and physical properties will be described.

  14. The homunculus of Eta Carinae: An interacting stellar winds paradigm

    NASA Technical Reports Server (NTRS)

    Frank, Adam; Balick, Bruce; Davidson, Kris

    1995-01-01

    We simulate the origin and evolution of the bipolar nebula surrounding Eta Car using numerical two-dimensional gasdynamic models. The generalized interacting stellar winds scenario, wherein a stellar wind interacts with an aspherical circumstellar environment, is adopted. The eruption wind of 1840-1860, which is taken to be spherically symmetric, interacts with a preeruption toroidal density environment. Using reasonable assumptions of initial conditions and eruption parameters based on archival data, we have performed over 30 simulations in an effort to bracket the initial parameters which produce models that best match observations. We find that models with high pole-to-equator density contrasts (greater than 100) and toroidal density configurations nicely account for the observed morphology and kinematics of the homunculus.

  15. Little Homunculus with in the Homunculus of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Ishibashi, Kazunori; Gull, Theodore R.; Davidson, Kris; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    The famous HST/WFPC2 images of Eta Carinae provide a two-dimensional projection of the bipolar nebula that is really a three-dimensional structure. Much is hidden in subtle, projected details that a velocity-tuned instrument can pull apart. We have used the HST/STIS with a 52" x 0.1" aperture and with about 5000 spectral resolving power to examine the kinetic information contained within emission/absorption features. By velocity tuning, we can translate this information into spatial structures. The spectroscopic datasets have been transformed to a set of images, spaced at half instrumental line width steps, 15 - 20 km/s , and with a spatial resolution of 0.1 x 0.1 arcsec near Balmer beta and 0.25 x 0.1 arcsec near Balmer alpha. We examined these narrow-band images and individual spectra to characterize the nature of an internal nebula (formerly known as the Integral nebula). The shape of this nebulosity is an bipolar nebula, deeply embedded within the Homunculus, the well-known bipolar nebula surrounding Eta Carinae. The internal nebula is shaped nearly identically to the Homunculus. It is best described as a "little Homunculus within the Homunculus". Indeed, it is reminiscent of the Russian dolls, known as Matryoshka dolls, that successively nest within each larger doll. For that reason, we call this internal nebula the Matryoshka nebula. This was performed as one of the STIS GTO key projects and was funded by the HST project. Observations were done through the STScI.

  16. The Time Evolution of Eta Carinae's Colliding Winds

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Madura, T. I.; Grobe, J. H.; Corcoran, M. F.

    2011-01-01

    We report new HST/STIS observations that map the high-ionization forbidden line emission in the inner arc second of Eta Car, the first that fully image the extended wind-wind interaction region of the massive colliding wind binary. These observations were obtained after the 2009.0 periastron at orbital phases 0.084, 0.163, and 0.323 of the 5.54-year spectroscopic cycle. We analyze the variations in brightness and morphology of the emission, and find that blue-shifted emission (-400 to -200 km/s is symmetric and elongated along the northeast-southwest axis, while the red-shifted emission (+ 100 to +200 km/s) is asymmetric and extends to the north-northwest. Comparison to synthetic images generated from a 3-D dynamical model strengthens the 3-D orbital orientation found by Madura et al. (2011), with an inclination i = 138 deg, argument of periapsis w = 270 deg, and an orbital axis that is aligned at the same P A on the sky as the symmetry axis of the Homunculus, 312 deg. We discuss the potential that these and future mappings have for constraining the stellar parameters of the companion star and the long-term variability of the system. Plain-Language Abstract: With HST, we resolved the interacting winds of the binary, Eta Carinae. With a 3-D model, we find the binary orbit axis is aligned to the Homunculus axis. This suggests a connection between the binary and Homunculus ejection mechanism.

  17. TDR Technique for Estimating the Intensity of Evapotranspiration of Turfgrasses

    PubMed Central

    Janik, Grzegorz; Wolski, Karol; Daniel, Anna; Albert, Małgorzata; Skierucha, Wojciech; Wilczek, Andrzej; Szyszkowski, Paweł; Walczak, Amadeusz

    2015-01-01

    The paper presents a method for precise estimation of evapotranspiration of selected turfgrass species. The evapotranspiration functions, whose domains are only two relatively easy to measure parameters, were developed separately for each of the grass species. Those parameters are the temperature and the volumetric moisture of soil at the depth of 2.5 cm. Evapotranspiration has the character of a modified logistic function with empirical parameters. It assumes the form ETR(θ2.5 cm, T2.5 cm) = A/(1 + B · e−C·(θ2.5 cm · T2.5 cm)), where: ETR(θ2.5 cm, T2.5 cm) is evapotranspiration [mm·h−1], θ2.5 cm is volumetric moisture of soil at the depth of 2.5 cm [m3·m−3], T2.5 cm is soil temperature at the depth of 2.5 cm [°C], and A, B, and C are empirical coefficients calculated individually for each of the grass species [mm·h1], and [—], [(m3·m−3·°C)−1]. The values of evapotranspiration calculated on the basis of the presented function can be used as input data for the design of systems for the automatic control of irrigation systems ensuring optimum moisture conditions in the active layer of lawn swards. PMID:26448964

  18. Changes in reference evapotranspiration over an agricultural region in the Qinghai-Tibetan plateau, China

    NASA Astrophysics Data System (ADS)

    Zhang, Cungui; Shen, Yanjun; Liu, Fenggui; Meng, Lei

    2016-01-01

    Reference evapotranspiration (ET0), as an estimate of the evaporative demand of the atmosphere, has been receiving extensive attention in researches on hydrological cycle. Sensitivity of ET0 to major climatic variables has significant applications in climatology, hydrology, and agrometeorology and is also important to improve our understanding of the connections between climatic conditions and ET0 variability. In this study, we used the Penman-Monteith equation to calculate ET0 and adopted a nondimensional sensitivity coefficient formula to analyze sensitivities of ET0 to four climatic variables based on daily meteorological data from eight meteorological sites in the Huangshui River basin and surrounding areas during 1961-2010. The results indicated that (1) strong correlations with R 2 up to 0.76 exist between observed E pan and calculated annual ET0; (2) ET0 had a decreasing trend in the Huangshui River basin (HRB) during 1961-2010; (3) Spatially, distribution of ET0 was largely correlated with altitude, for instance, the average annual ET0 was larger in low-altitude areas than in high-altitude areas; (4) ET0 was more sensitive to actual vapor pressure in high-altitude areas while it was more sensitive to temperature in low-altitude areas; and (5) ET0 showed a decreasing trend and was consistent with the decreases in net radiation and wind speed at seasonal and annual time scales in HRB during 1961-2010. Sensitivity analysis of ET0 to major climatic variables revealed that temperature was primarily responsible for changes in ET0 in the growing season while actual vapor pressure was the dominating factor causing changes in ET0 in the nongrowing season. However, annual averaged ET0 was more sensitive to actual vapor pressure ( R 2 = 0.63), indicating that actual vapor pressure was possibly the primary climatic variable that causes changes in annual ET0.

  19. Spatial evapotranspiration, rainfall and land use data in water accounting - Part 1: Review of the accuracy of the remote sensing data

    NASA Astrophysics Data System (ADS)

    Karimi, P.; Bastiaanssen, W. G. M.

    2014-01-01

    The scarcity of water encourages scientists to develop new analytical tools to enhance water resource management. Water accounting and distributed hydrological models are examples of such tools. Water accounting needs accurate input data for adequate descriptions of water distribution and water depletion in river basins. Ground-based observatories are decreasing, and remote sensing data is a suitable alternative to measure the required input variables. This paper reviews the reliability of remote sensing algorithms to accurately determine the spatial distribution of actual evapotranspiration, rainfall and land use. For our validation we used only those papers that covered study periods of one season to annual cycles because the accumulated water balance is the primary concern. Review papers covering shorter periods only (days, weeks) were not included in our review. Our review shows that by using remote sensing, the spatial distribution of evapotranspiration can be mapped with an overall accuracy of 95% (STD 5%) and rainfall with an overall accuracy of 82% (STD 15%). Land use can be identified with an overall accuracy of 85% (STD 7%). Hence, more scientific work is needed to improve spatial mapping of rainfall using multiple space-borne sensors. Actual evapotranspiration maps can be used with confidence in water accounting and hydrological modeling.

  20. Evapotranspiration as a component of water footprint: use of conventional and satellite data for better estimation of spatial and temporal pattern

    NASA Astrophysics Data System (ADS)

    Struzik, Piotr; Kepinska-Kasprzak, Malgorzata

    2014-08-01

    One of the main scientific goals of the COST Action ES1106 ("Assessment of European Agriculture Water use and Trade under Climate Change" EURO-AGRIWAT) is the analysis of the global water footprint (WF) in agriculture and virtual water trade (VWT). The starting point for further activities is analyses and inventory of data and tools which could be helpful for WF and WFT assessments. Evaporation values (ET) are crucial for agriculture where estimates of water reserves available for crops are the basis for scheduling the time and intensity of irrigation, yield prognoses, etc. Detail evapotranspiration data are, therefore, of essential value. However, stations performing direct measurements of evapotranspiration are very scarcely distributed in Poland for which reason the interpolation of the data is necessarily biased. Hence, evapotranspiration values are calculated using indirect methods (usually empirical formulas). Data from geostationary meteorological satellites are used operationally for determination of evapotranspiration with good spatial and temporal resolution (e.g. Land-SAF product). Study of relation between evapotranspiration values determined with use of satellite data and calculated using Penman-Monteith formula was performed for the study area in Poland. Daily values and cumulated (i.e. decadal, monthly and yearly) values were analyzed to determine quality and possible added value of the satellite product. Relation between reference ET and actual ET in two consecutive years was discussed, both for whole test area and individual stations, taking into account land use and possible water deficit in the root region, represented by H-SAF soil wetness index product. The differences were presented and discussed.

  1. Evaluation of Physically and Empirically Based Models for the Estimation of Green Roof Evapotranspiration

    NASA Astrophysics Data System (ADS)

    Digiovanni, K. A.; Montalto, F. A.; Gaffin, S.; Rosenzweig, C.

    2010-12-01

    Green roofs and other urban green spaces can provide a variety of valuable benefits including reduction of the urban heat island effect, reduction of stormwater runoff, carbon sequestration, oxygen generation, air pollution mitigation etc. As many of these benefits are directly linked to the processes of evaporation and transpiration, accurate and representative estimation of urban evapotranspiration (ET) is a necessary tool for predicting and quantifying such benefits. However, many common ET estimation procedures were developed for agricultural applications, and thus carry inherent assumptions that may only be rarely applicable to urban green spaces. Various researchers have identified the estimation of expected urban ET rates as critical, yet poorly studied components of urban green space performance prediction and cite that further evaluation is needed to reconcile differences in predictions from varying ET modeling approaches. A small scale green roof lysimeter setup situated on the green roof of the Ethical Culture Fieldston School in the Bronx, NY has been the focus of ongoing monitoring initiated in June 2009. The experimental setup includes a 0.6 m by 1.2 m Lysimeter replicating the anatomy of the 500 m2 green roof of the building, with a roof membrane, drainage layer, 10 cm media depth, and planted with a variety of Sedum species. Soil moisture sensors and qualitative runoff measurements are also recorded in the Lysimeter, while a weather station situated on the rooftop records climatologic data. Direct quantification of actual evapotranspiration (AET) from the green roof weighing lysimeter was achieved through a mass balance approaches during periods absent of precipitation and drainage. A comparison of AET to estimates of potential evapotranspiration (PET) calculated from empirically and physically based ET models was performed in order to evaluate the applicability of conventional ET equations for the estimation of ET from green roofs. Results have

  2. Vapor pressure deficit is as important as soil moisture in determining limitations to evapotranspiration during drought

    NASA Astrophysics Data System (ADS)

    Novick, K. A.; Williams, C. A.; Phillips, R.; Oishi, A. C.; Sulman, B. N.; Bohrer, G.; Ficklin, D. L.

    2015-12-01

    The decoupling between potential evapotranspiration (PET) and actual evapotranspiration (AET) is a useful metric to characterize ecosystem hydrologic stress. As hydrologic stress evolves, PET increases following increases in incident radiation and vapor pressure deficit (VPD). AET, on the other hand, remains stationary or decreases due to declines in surface conductance imposed by decreasing soil water and stomatal closure under high VPD. Historically, it has been difficult to quantify the extent to which soil moisture as compared to VPD ultimately limits AET during hydrologic stress. Part of this difficulty relates to the strong correlation between soil moisture and VPD at timescales over which hydrologic stress evolves (weekly to monthly). Further, while it is relatively easy to manipulate soil moisture in experimental settings, manipulating VPD is much more difficult. Recently, the proliferation of eddy covariance flux sites has produced a rich collection of AET observations at fine timescales (i.e. hourly to daily) over which VPD and soil moisture are more decoupled. In this study, we leverage such data to quantify the extent to which soil moisture versus VPD constrains AET in more than 25 Ameriflux sites spanning a wide climate gradient. We found that AET was most significantly limited by soil moisture in dry sites where the annual PET was much higher than precipitation. VPD limitations to AET dominated in wetter sites, but even among the driest sites, they were of similar magnitude to soil moisture limitations. Our results highlight the critical, if at time underappreciated, role of VPD in determining ecohydrological functioning during periods of hydrologic stress. We also leverage these results together with future projections for VPD, soil moisture, and other relevant meteorological drivers to explore the extent to which the coherence between VPD and soil moisture, and their relative importance for limiting AET, may shift under future climate conditions.

  3. Use of the Aquacrop model for the simulation of wheat evapotranspiration in north-eastern Tunisia

    NASA Astrophysics Data System (ADS)

    Aloui, A.; Masmoudi, M.; Jacob, F.; Ben Mechlia, N.

    2012-04-01

    Improvement of rainfed cropping systems is based on the use of rainfall water for crop transpiration. This could be achieved by the appropriate partitioning of rainfall between green water and blue water. Under semiarid conditions, the AquaCrop model which has a driving engine based on the direct link between dry matter production and crop evapotranspiration, seems to be a powerful tool to perform this task. For this purposes, an experimental work was conducted on the wheat crop, grown under various farming conditions, to determine how simulation modeling could be used to monitor canopy changes and actual crop evapotranspiration. The study area -CapBon- is located in north eastern Tunisia where rainfall is about 500 mm and ET0 around 1200mm Field monitoring consisted in regular measurements of the leaf area index (LAI), vegetation cover changes (CC) and soil moisture content profiles over the cropping season December 2009-April 2010. The usefulness of using hemispherical and standard images to determine LAI and CC was also investigated for their adoption as a standard methods for the assessment of these important parameter as input data. Results show that good estimates of LAI and CC could be obtained from digital images. Fairly reliable linear relationships were obtained between measurements on samples using a leaf area meter and indirect assessments (r2 = 0.78) Aqua-Crop simulations where also mostly accurate in estimating soil moisture temporal variations and soil water content of well textured soils. However for soils with high clay content, important differences were observed between simulation outputs and direct gravimetric measurements.

  4. Mapping daily evapotranspiration at Landsat spatial scales during the BEAREX'08 field campaign

    NASA Astrophysics Data System (ADS)

    Anderson, Martha C.; Kustas, William P.; Alfieri, Joseph G.; Gao, Feng; Hain, Christopher; Prueger, John H.; Evett, Steven; Colaizzi, Paul; Howell, Terry; Chávez, José L.

    2012-12-01

    Robust spatial information about environmental water use at field scales and daily to seasonal timesteps will benefit many applications in agriculture and water resource management. This information is particularly critical in arid climates where freshwater resources are limited or expensive, and groundwater supplies are being depleted at unsustainable rates to support irrigated agriculture as well as municipal and industrial uses. Gridded evapotranspiration (ET) information at field scales can be obtained periodically using land-surface temperature-based surface energy balance algorithms applied to moderate resolution satellite data from systems like Landsat, which collects thermal-band imagery every 16 days at a resolution of approximately 100 m. The challenge is in finding methods for interpolating between ET snapshots developed at the time of a clear-sky Landsat overpass to provide complete daily time-series over a growing season. This study examines the efficacy of a simple gap-filling algorithm designed for applications in data-sparse regions, which does not require local ground measurements of weather or rainfall, or estimates of soil texture. The algorithm relies on general conservation of the ratio between actual ET and a reference ET, generated from satellite insolation data and standard meteorological fields from a mesoscale model. The algorithm was tested with ET retrievals from the Atmosphere-Land Exchange Inverse (ALEXI) surface energy balance model and associated DisALEXI flux disaggregation technique, which uses Landsat-scale thermal imagery to reduce regional ALEXI maps to a finer spatial resolution. Daily ET at the Landsat scale was compared with lysimeter and eddy covariance flux measurements collected during the Bushland Evapotranspiration and Agricultural Remote sensing EXperiment of 2008 (BEAREX08), conducted in an irrigated agricultural area in the Texas Panhandle under highly advective conditions. The simple gap-filling algorithm performed

  5. RIP-ET: A riparian evapotranspiration package for MODFLOW-2005

    USGS Publications Warehouse

    Maddock, Thomas, III; Baird, Kathryn J.; Hanson, R.T.; Schmid, Wolfgang; Ajami, Hoori

    2012-01-01

    A new evapotranspiration package for the U.S. Geological Survey's groundwater-flow model, MODFLOW, is documented. The Riparian Evapotranspiration Package (RIP-ET) provides flexibility in simulating riparian and wetland transpiration not provided by the Evapotranspiration (EVT) or Segmented Function Evapotranspiration (ETS1) Packages for MODFLOW 2005. This report describes how the RIP-ET package was conceptualized and provides input instructions, listings and explanations of the source code, and an example. Traditional approaches to modeling evapotranspiration (ET) processes assume a piecewise linear relationship between ET flux and hydraulic head. The RIP-ET replaces this traditional relationship with a segmented, nonlinear dimensionless curve that reflects the eco-physiology of riparian and wetland ecosystems. Evapotranspiration losses from these ecosystems are dependent not only on hydraulic head, but on the plant types present. User-defined plant functional groups (PFGs) are used to elucidate the interaction between plant transpiration and groundwater conditions. Five generalized plant functional groups based on transpiration rates, plant rooting depth, and water tolerance ranges are presented: obligate wetland, shallow-rooted riparian, deep-rooted riparian, transitional riparian and bare ground/open water. Plant functional groups can be further divided into subgroups (PFSGs) based on plant size, density or other characteristics. The RIP-ET allows for partial habitat coverage and mixtures of plant functional subgroups to be present in a single model cell. RIP-ET also distinguishes between plant transpiration and bare-ground evaporation. Habitat areas are designated by polygons; each polygon can contain a mixture of PFSGs and bare ground, and is assigned a surface elevation. This process requires a determination of fractional coverage for each of the plant functional subgroups present in a polygon to account for the mixture of coverage types and resulting

  6. Further Investigation Of The Winds Of Eta Car A And B

    NASA Astrophysics Data System (ADS)

    Nielsen, Krister E.; Corcoran, M. F.; Gull, T. R.; Hamaguchi, K.; Hillier, D. J.; Weis, K.

    2007-12-01

    A majority of all observations of Eta Car supports the suggested duality of the system, but the conditions in the inner core of the nebula and, especially, the character of Eta Car B, evade direct measurements. We utilize VLT/UVES spectra obtained either by observing the system in line-of-sight towards the stellar system; or via radiation reflected by the Homunculus. These additional vantage points provide information about the inhomogeneous and non-symmetric winds from the central objects, and how the system changes with orbital phase. We investigate the excitation/ionization conditions by tracing transitions with different spectral characteristics over the 5.54 yr orbital period. The nebular-scattered line profiles are compared with corresponding high-angular resolution HST/STIS observations in line-of-sight towards the Eta Car binary. The line dependent behavior, provides additional information in the quest to understand the Eta Car binary and its close environment.

  7. Recalculation of the coupling constants g{sub {rho}{eta}{gamma},} g{sub {omega}{eta}{gamma},} g{sub {eta}}{sup '}{sub {rho}{gamma},} and g{sub {eta}'{omega}{gamma}}in QCD sum rules

    SciTech Connect

    Aydin, C.; Yilmaz, A. H.; Bayar, M.

    2010-05-01

    We recalculated the coupling constants of {rho}({omega}){yields}{eta}{gamma} and {eta}{sup '{yields}{rho}}({omega}){gamma} decays especially with loop contributions in the case of axial-vector coupling in the method of QCD sum rules for dimension d=6. A comparison of our prediction on the coupling constants with the result obtained from analysis of the experimental data and calculations done before is performed.

  8. Bias in fitting the ETAS model: a case study based on New Zealand seismicity

    NASA Astrophysics Data System (ADS)

    Harte, D. S.

    2013-01-01

    We fit various forms of the ETAS model to a large region that includes all of the most seismically active areas of New Zealand. The ETAS model contains two components: a component describing background or immigrant events, and a part describing aftershocks of the background events and aftershocks of the aftershocks. We refer to the first part as the background part and the second as the ETAS part. Generally all of the sophistication, and the bulk of the model parameters, lies in the ETAS part of the model. The background component is generally treated as a nuisance component and is often very simplistic. While the main interest lies in the ETAS part of the model, the poor model description of the background part imposes considerable bias on the ETAS part of the model. For example, a poorly specified spatial density of the background events causes many of the background events to be seen as ETAS events. It can also cause the estimated Omori power-law decay p to be too small, and hence the aftershock sequences appear to continue for too long. On the other hand, the boundary of the observation region can impose a reverse bias which causes aftershocks that are close but within the boundary to be seen as background events. In almost all of the large NZ event sequences since 1965, the model consistently under-fits these sequences. Consequently, it over-fits those space-time regions where there is `normal' seismicity with no major events present. This may indicate that the space-time region of a major event sequence is much closer to criticality, in that aftershock events appear to be much more easily initiated. The standard ETAS model does not reflect this observation.

  9. PKC{eta} is a negative regulator of AKT inhibiting the IGF-I induced proliferation

    SciTech Connect

    Shahaf, Galit; Rotem-Dai, Noa; Koifman, Gabriela; Raveh-Amit, Hadas; Frost, Sigal A.; Livneh, Etta

    2012-04-15

    The PI3K-AKT pathway is frequently activated in human cancers, including breast cancer, and its activation appears to be critical for tumor maintenance. Some malignant cells are dependent on activated AKT for their survival; tumors exhibiting elevated AKT activity show sensitivity to its inhibition, providing an Achilles heel for their treatment. Here we show that the PKC{eta} isoform is a negative regulator of the AKT signaling pathway. The IGF-I induced phosphorylation on Ser473 of AKT was inhibited by the PKC{eta}-induced expression in MCF-7 breast adenocarcinoma cancer cells. This was further confirmed in shRNA PKC{eta}-knocked-down MCF-7 cells, demonstrating elevated phosphorylation on AKT Ser473. While PKC{eta} exhibited negative regulation on AKT phosphorylation it did not alter the IGF-I induced ERK phosphorylation. However, it enhanced ERK phosphorylation when stimulated by PDGF. Moreover, its effects on IGF-I/AKT and PDGF/ERK pathways were in correlation with cell proliferation. We further show that both PKC{eta} and IGF-I confer protection against UV-induced apoptosis and cell death having additive effects. Although the protective effect of IGF-I involved activation of AKT, it was not affected by PKC{eta} expression, suggesting that PKC{eta} acts through a different route to increase cell survival. Hence, our studies show that PKC{eta} provides negative control on AKT pathway leading to reduced cell proliferation, and further suggest that its presence/absence in breast cancer cells will affect cell death, which could be of therapeutic value.

  10. A fast cyber 205-ETA 10 program for SU(3) lattice gauge theory

    NASA Astrophysics Data System (ADS)

    Vohwinkel, Claus; Berg, Bernd A.; Devoto, Alberto

    1988-11-01

    We describe a Monte Carlo program that simulates SU(3) lattice gauge theoryon CYBER 205 and ETA 10 computers. The program uses the Cabibbo Marinari algorithm for the updating and a novel way of gathering neighbors. It achieves a 17.1 μs updating time per link on a 2-pipe CYBER 205 using 32-bit arithmetic. The updating time per link on the ETA 10 at Florida State University is 8.8 μs.

  11. Magnetic eta index and the ability to forecast sporadic E layer appearance

    NASA Astrophysics Data System (ADS)

    Dziak-Jankowska, Beata; Stanislawska, Iwona; Pozoga, Mariusz; Tomasik, Lukasz; Ernst, Tomasz

    2012-07-01

    We analysed the correlation of the changes of the magnetic vertical component with the ionospheric deviations from monthly median of the E layer characteristics. Promising results indicate that the eta parameter can be used to predict sporadic E layer during magnetically quiet days. Our previous work concern the data from only one year - 2004. During the descending phase of solar cycle in 2004 there was not numerous amount of quiet days. We extend our research to other years starting from 1996 and focusing on 2007 - 2009, years of the prolonged solar minimum. The analysis shows that under magnetically quiet circumstances the magnetic index eta indicates large magnetic disturbance, especially in vertical component when other magnetic indices inform about quiet magnetic conditions. The results indicate that the increase of the magnetic eta index (the ratio of the variations of vertical component of the external magnetic field to the horizontal component) is associated with the emergence of sporadic E layer or with increase of foEs critical frequency of sporadic E layer. The appearance of sporadic E layer followed 1-2 h after growth of magnetic index eta. An important conclusion is that the analysis of the hourly ionospheric data does not give 100% correlation between the increase of eta and the emergence of Es layer, however, studies of dense measurement data show that the correlation is almost 100%. An advantage of the eta index is the fact that after eliminating the effect of currents induced within the Earth, eta index bring independent and meaningful information on the system of current in the ionosphere. Hence, the eta index could be an important element of the ionosphere monitoring and can be used to predict such local phenomenon like the appearance of the sporadic E layer.

  12. Structural basis for the suppression of skin cancers by DNA polymerase [eta

    SciTech Connect

    Silverstein, Timothy D.; Johnson, Robert E.; Jain, Rinku; Prakash, Louise; Prakash, Satya; Aggarwal, Aneel K.

    2010-09-13

    DNA polymerase {eta} (Pol{eta}) is unique among eukaryotic polymerases in its proficient ability for error-free replication through ultraviolet-induced cyclobutane pyrimidine dimers, and inactivation of Pol{eta} (also known as POLH) in humans causes the variant form of xeroderma pigmentosum (XPV). We present the crystal structures of Saccharomyces cerevisiae Pol{eta} (also known as RAD30) in ternary complex with a cis-syn thymine-thymine (T-T) dimer and with undamaged DNA. The structures reveal that the ability of Pol{eta} to replicate efficiently through the ultraviolet-induced lesion derives from a simple and yet elegant mechanism, wherein the two Ts of the T-T dimer are accommodated in an active site cleft that is much more open than in other polymerases. We also show by structural, biochemical and genetic analysis that the two Ts are maintained in a stable configuration in the active site via interactions with Gln55, Arg73 and Met74. Together, these features define the basis for Pol{eta}'s action on ultraviolet-damaged DNA that is crucial in suppressing the mutagenic and carcinogenic consequences of sun exposure, thereby reducing the incidence of skin cancers in humans.

  13. New ruthenium carboxylate complexes having a 1-5-. eta. sup 5 -cyclooctadienyl ligand

    SciTech Connect

    Osakada, Kohtaro; Grohmann, A.; Yamamoto, Akio )

    1990-07-01

    Reaction of 3-butenoic acid with Ru(cod)(cot) (cod) = 1-2-{eta}{sup 2}:5-6-{eta}{sup 2}-cyclooctadiene; cot = 1-6-{eta}{sup 6}-cyclooctatriene in the presence of PMe{sub 3} gives a new ruthenium(II) complex formulated as Ru(1-5-{eta}{sup 5}-C{sub 8}H{sub 11}){eta}{sup 1}(O),{eta}{sup 2}(C,C{prime}-OCOCH{sub 2}CH{double bond}CH{sub 2})(PMe{sub 3}) (1). X-ray crystallography revealed its structure as having a piano-stool coordination around the ruthenium center. Crystals of 1 are tetragonal, space group P4{sub 3}2{sub 1}2, with a = 12.559 (3) {angstrom}, c = 20.455 (4) {angstrom}, and Z = 8. {sup 1}H and {sup 13}C({sup 1}H) NMR spectra of 1 agree well for the structure with the allyl entity of the carboxylate {pi}-bonded through the C{double bond}C double bond to ruthenium.

  14. Measurement of the gamma gamma* to eta_c transition form factor

    SciTech Connect

    Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; Hawkes, C.M.; /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Indian Inst. Tech., Guwahati /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas Nuclear Corp., Austin /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

    2010-04-28

    The authors study the reaction e{sup +}e{sup -} {yields} e{sup +}e{sup -} {eta}{sub c}, {eta}{sub c} {yields} K{sub S}K{sup {+-}}{pi}{sup {-+}} and obtain {eta}{sub c} mass and width values 2982.2 {+-} 0.4 {+-} 1.6 MeV/c{sup 2} and 31.7 {+-} 1.2 {+-} 0.8 MeV, respectively. They find {Lambda}({eta}{sub c} {yields} {gamma}{gamma}){Beta}({eta}{sub c} {yields} K{bar K}{pi}) = 0.374 {+-} 0.009 {+-} 0.031 keV, and measure the {gamma}{gamma}* {yields} {eta}{sub c} transition form factor in the momentum transfer range from 2 to 50 GeV{sup 2}. The analysis is based on 469 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.

  15. Precision Measurement of {eta} --> {gamma} {gamma} Decay Width via the Primakoff Effect

    SciTech Connect

    Gan, Liping Gin

    2013-08-01

    A precision measurement of the {eta} --> {gamma} {gamma} decay width via the Primakoff effect is underway in Hall D at Jefferson Lab. The decay width will be extracted from measured differential cross sections at forward angles on two light targets, liquid hydrogen and 4He, using a 11.5 GeV tagged photon beam. Results of this experiment will not only potentially resolve a long standing discrepancy between the Primakoff and the collider measurements, but will also reduce the experimental uncertainty by a factor of two on the average value of previous experimental results listed by the Particle Data Group(PDG). It will directly improve all other eta partial decay widths which rely on the accuracy of the eta radiative decay width. The projected 3% precision on the {Gamma}({eta} --> {gamma} {gamma} ) measurement will have a significant impact on the experimental determination of the fundamental parameters in QCD, such as the ratio of light quark masses (m{sub u},m{sub d},m{sub s}) and the {eta} - {eta}' mixing angle. It will be a sensitive probe for understanding QCD symmetries and the origin and the dynamics of QCD symmetry breaking.

  16. Eta Carinae and the Homunculus: an Astrophysical Laboratory

    NASA Astrophysics Data System (ADS)

    Gull, Theodore R.; Hartman, H.; Bautista, M. A.

    2012-05-01

    Today Eta Carinae, from the 1840s Great Eruption, is surrounded by a 20", neutral, dusty bipolar shell with intervening skirt, containing 12-40 solar masses of N-rich, C- and O-poor ejecta. The ionized Little Homunculus, ejected in the 1890s, expands within. At the core are a massive extended interacting wind structure and the bright Weigelt blobs, that change between a low-ionization (<7.8 eV) to a high-ionization state (>40 eV) driven by the 5.5-year massive binary. Thousands of narrow emission and absorption lines originate from a variety of regions: 1) the Weigelt blobs and the extended wind structures; 2) the Strontium Filament, a unique photoioionized metal nebula dominated by TiII, VII, SrII, ScII, CaII, MnII, CrII and FeI, but no HI; 3) the ionized Little Homunculus; and 4) the Homunculus seen in nearly a thousand atomic absorption lines in high and low states, but a thousand H2 absorptions only seen in the high state. Ionized iron-peak elements co-exist with CH, OH, NH and H2. This system is an excellent laboratory for the study of many iron-peak species from neutral to doubly-ionized states. The variations of incident radiation allow us to study atomic processes and derive atomic data not available from terrestrial laboratories, making Eta Carinae an astrophysical laboratory in its true sense. Moreover, the Homunculus, as inventoried by Herschel spectral scans, is dominated by N-bearing molecules. While C and O are depleted nearly 100-fold, due to CNO-nuclear reactions coupled with high conduction in the massive stellar cores, dust and molecules have still formed. How? Is the Homunculus dust metallic in character? Silicates and alumina? Could the formed dust also contribute to the C,O-depletions? Through multiple studies we are gaining clues on the robustness of molecular and dust formations.

  17. Geohydrology and evapotranspiration at Franklin Lake Playa, Inyo County, California

    SciTech Connect

    1990-12-01

    Franklin Lake playa is one of the principal discharge areas of the Furnace Creek Ranch-Alkali Flat ground-water-flow system in southern Nevada and adjacent California. Yucca Mountain, Nevada, located within this flow system, is being evaluated by the US Department of Energy to determine its suitability as a potential site for a high-level nuclear-waste repository. To assist the US Department of Energy with its evaluation of the Yucca Mountain site, the US Geological Survey developed a parameter-estimation model of the Furnace Creek Ranch-Alkali Flat ground-water-flow system. Results from sensitivity analyses made using the parameter-estimation model indicated that simulated rates of evapotranspiration at Franklin Lake playa had the largest effect on the calculation of transmissivity values at Yucca Mountain of all the model-boundary conditions and, therefore, that evapotranspiration required careful definition. 72 refs., 59 figs., 26 tab.

  18. Geohydrology and evapotranspiration at Franklin Lake playa, Inyo County, California

    SciTech Connect

    Czarnecki, J.B.

    1997-12-31

    Franklin Lake playa is one of the principal discharge areas of the Furnace Creek Ranch-Alkali Flat ground-water-flow system in southern Nevada and adjacent California. Yucca Mountain, Nevada, located within this flow system, is being evaluated by the US Department of Energy to determine its suitability as a potential site for a high-level nuclear-waste repository. To assist the U.S. Department of Energy with its evaluation of the Yucca Mountain site, the US Geological Survey developed a parameter-estimation model of the Furnace Creek Ranch-Alkali Flat ground-water-flow system. Results from sensitivity analyses made using the parameter-estimation model indicated that simulated rates of evapotranspiration at Franklin Lake playa had the largest effect on the calculation of transmissivity values at Yucca Mountain of all the model-boundary conditions and, therefore, that evapotranspiration required careful definition.

  19. Soil moisture and evapotranspiration predictions using Skylab data

    NASA Technical Reports Server (NTRS)

    Myers, V. I. (Principal Investigator); Moore, D. G.; Horton, M. L.; Russell, M. J.

    1975-01-01

    The author has identified the following significant results. Multispectral reflectance and emittance data from the Skylab workshop were evaluated for prediction of evapotranspiration and soil moisture for an irrigated region of southern Texas. Wavelengths greater than 2.1 microns were required to spectrally distinguish between wet and dry fallow surfaces. Thermal data provided a better estimate of soil moisture than did data from the reflective bands. Thermal data were dependent on soil moisture but not on the type of agricultural land use. The emittance map, when used in conjunction with existing models, did provide an estimate of evapotranspiration rates. Surveys of areas of high soil moisture can be accomplished with space altitude thermal data. Thermal data will provide a reliable input into irrigation scheduling.

  20. 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.

  1. How do alternative root water uptake models affect the inverse estimation of soil hydraulic parameters and the prediction of evapotranspiration?

    NASA Astrophysics Data System (ADS)

    Gayler, Sebastian; Salima-Sultana, Daisy; Selle, Benny; Ingwersen, Joachim; Wizemann, Hans-Dieter; Högy, Petra; Streck, Thilo

    2016-04-01

    equation combined with the Mualem-van Genuchten approach to parametrize the soil hydraulic functions was coupled to three different root-water uptake modules according to Nimah & Hanks, Feddes, and van Genuchten. Potential evapotranspiration was estimated following Penman-Monteith, whereas leaf area index and rooting depth were predefined model inputs derived from observations. Simulation results were compared to 3-year time-series of time-domain reflectometry measurements of soil moisture in two to five different depths (depending on solum thickness) and eddy-covariance measurements of evapotranspiration. Data of two growing seasons (2010, 2011) were used for the inverse estimation of saturated water content, saturated hydraulic conductivity and the van Genuchten parameters α and n using the universal optimization tool UCODE. Data from the growing season 2012 were used for model validation. The model calibration results showed a similar and acceptable goodness of fit between simulated and observed soil water contents and actual evapotranspiration for all there models. There was no substantial difference in model performance between the alternative root water uptake models during the calibration phase 2010-2011. However, the values of the optimized soil hydraulic parameters substantially differed in some cases, resulting in an increased model uncertainty during the prediction phase 2012, especially during phases of strong drying out of the soil. Albeit single model combinations are superior over the others for single locations with respect to the different observables (soil moisture, evapotranspiration), none of the models outcompeted the others over all years, locations and observables. We conclude that model solutions cannot be considered unique when different process representations are selected and the respective soil hydraulic parameters fitted (equifinality problem).

  2. Climate Change Impact on Evapotranspiration, Heat Stress and Chill Requirements

    NASA Astrophysics Data System (ADS)

    Snyder, R. L.; Marras, S.; Spano, D.

    2013-12-01

    Carbon dioxide concentration scenarios project an increase in CO2 from 372 ppm to between 500 and 950 ppm by the year 2100, and the potential effect on temperature, humidity, and plant responses to environmental factors are complex and concerning. For 2100, mean daily temperature increase projections range from 1.2oC to 6.8oC depending on greenhouse gas emissions. On the bad side, higher temperatures are often associated with increases in evapotranspiration (ET), heat stress, and pest infestations. On the good side, increased temperature is commonly related to less frost damage, faster growth, and higher production in some cases. One misconception is that global warming will increase evapotranspiration and, hence, agricultural water demand. As the oceans and other water bodies warm, evaporation and humidity are likely to increase globally, but higher humidity tends to reduce plant transpiration and hence ET. Higher CO2 concentrations also tend to reduce ET, and, in the end, the increase in ET due to higher temperature is likely to be offset by a decrease in ET due to higher humidity and CO2. With a decrease in daytime evapotranspiration, the canopy temperature is likely to rise relative to the air temperature, and this implies that heat stress could be worse than predicted by increased air temperature. Daily minimum temperatures are generally increasing about twice as fast as maximum temperatures presumably because of the increasing dew point temperatures as more water vapor is added to the atmosphere. This could present a serious problem to meet the chill requirement for fruit and nut crops. Growing seasons, i.e., from the last spring to the first fall frost, are likely to increase, but the crop growth period is likely to shorten due to higher temperature. Thus, spring frost damage is unlikely to change but there should be fewer damaging fall frost events. In this paper, we will present some ideas on the possible impact of climate change on evapotranspiration and

  3. Evamapper: A Novel Matlab Toolbox For Evapotranspiration Mapping

    NASA Astrophysics Data System (ADS)

    Atasever, Ü. H.; Kesikoğlu, M. H.; Özkan, C.

    2013-10-01

    Water consumption has been exceeding as the world population increases. Therefore, it is very important to manage water resources with care as it is not an endless resource. The Water loss in regional scale is the key phenomena to accomplish this goal. One of the main components of this phenomenon is evapotraspiration (ET) due to being one of the most important parameter for the management of water resources. Until recent years, evapotranspiration calculations were performed locally, using data obtained from weather stations. But for a successful water management, regional evapotranspiration maps are required. Different approaches are used to compute regional ETs. Among them, the direct measurement methods are not cost-effective and regionalized. For costeffective and regional ET mapping, Surface Energy Balance Algorithm (SEBAL) is the most known and effective technique. In this study, EvaMapper Toolbox which is based on SEBAL approach are developed for regional evapotranspiration mapping in MATLAB. By this toolbox, researchers can apply SEBAL technique which has a very complex structure to their study area easily through entering regional parameter values.

  4. Evapotranspiration studies for protective barriers: FY 1990 status report

    SciTech Connect

    Link, S.O.; Downs, J.L.; Thiede, M.E.; Lettau, D.J.; Twaddell, T.R.; Black, R.A.

    1992-05-01

    Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company (Westinghouse Hanford) are working together to develop for the US Department of Energy (DOE) protective barriers for the near-surface disposal of hazardous waste at the Hanford Site. The proposed barrier design consists of a layer of fine-textured soil overlying a series of layers grading from sand to basalt riprap. A multiyear research program is being conducted to assess the long-term performance of barrier configurations in restricting plants, animals, and water from contacting buried wastes. The purpose of this report is to review work done up to July 31 in FY 1990 on the evapotranspiration subtask of the water infiltration task. As stated in the test plan, specific objectives of PNL`s evapotranspiration work were to (1) develop and test an environmentally controlled whole-plant gas exchange system, (2) collect evapotranspiration data at the whole-plant level on the small-tube lysimeters, (3) collect transpiration data on the shrubs at McGee Ranch, (4) collect data necessary to parameterize the plant component of the UNSAT-H code.

  5. Evapotranspiration studies for protective barriers: FY 1990 status report

    SciTech Connect

    Link, S.O.; Downs, J.L.; Thiede, M.E.; Lettau, D.J.; Twaddell, T.R. ); Black, R.A. )

    1992-05-01

    Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company (Westinghouse Hanford) are working together to develop for the US Department of Energy (DOE) protective barriers for the near-surface disposal of hazardous waste at the Hanford Site. The proposed barrier design consists of a layer of fine-textured soil overlying a series of layers grading from sand to basalt riprap. A multiyear research program is being conducted to assess the long-term performance of barrier configurations in restricting plants, animals, and water from contacting buried wastes. The purpose of this report is to review work done up to July 31 in FY 1990 on the evapotranspiration subtask of the water infiltration task. As stated in the test plan, specific objectives of PNL's evapotranspiration work were to (1) develop and test an environmentally controlled whole-plant gas exchange system, (2) collect evapotranspiration data at the whole-plant level on the small-tube lysimeters, (3) collect transpiration data on the shrubs at McGee Ranch, (4) collect data necessary to parameterize the plant component of the UNSAT-H code.

  6. Analysis of potential evapotranspiration using limited weather data

    NASA Astrophysics Data System (ADS)

    Valipour, Mohammad

    2014-09-01

    The most important weather variations are temperature (T), relative humidity (RH), and wind speed (u) for evapotranspiration models in limited data conditions. This study aims to compare three T-based formula, T/RH-based formula, and T/RH/u-based formula to detect the performance of them under limited data and different weather conditions. For this purpose, weather data were gathered from 181 synoptic stations in 31 provinces of Iran. The potential evapotranspiration was compared with the FAO Penman-Monteith method. The results showed that T-based formula, T/RH-based formula, and T/RH/u-based formula estimated potential evapotranspiration with R 2 >0.93 for 6, 12, and 30 provinces of Iran, respectively. They are more suitable for southeast of Iran (YA, KE, SB, and SK). The best precise method was the T/RH/u-based formula for SK and GO. Finally, a list of the best performance of each method has been presented to use other regions and next researches according to values of temperature, relative humidity, and wind speed. The best weather conditions to use the formulas are 14-26 °C and 2.50-3.50 m/s for temperature and wind speed, respectively.

  7. Moral Reasoning in Hypothetical and Actual Situations.

    ERIC Educational Resources Information Center

    Sumprer, Gerard F.; Butter, Eliot J.

    1978-01-01

    Results of this investigation suggest that moral reasoning of college students, when assessed using the DIT format, is the same whether the dilemmas involve hypothetical or actual situations. Subjects, when presented with hypothetical situations, become deeply immersed in them and respond as if they were actual participants. (Author/BEF)

  8. Factors Related to Self-Actualization.

    ERIC Educational Resources Information Center

    Hogan, H. Wayne; McWilliams, Jettie M.

    1978-01-01

    Provides data to further support the notions that females score higher in self-actualization measures and that self-actualization scores correlate inversely to the degree of undesirability individuals assign to their heights and weights. Finds that, contrary to predictions, greater androgyny was related to lower, not higher, self-actualization…

  9. Estimation of Regional Evapotranspiration Using Remotely Sensed Land Surface Temperature. Part 1: Measurement of Evapotranspiration at the Environmental Research Center and Determination of Priestley-taylor Parameter

    NASA Technical Reports Server (NTRS)

    Kotada, K.; Nakagawa, S.; Kai, K.; Yoshino, M. M.; Takeda, K.; Seki, K.

    1985-01-01

    In order to study the distribution of evapotranspiration in the humid region using remote sensing technology, the parameter (alpha) in the Priestley-Taylor model was determined. The daily means of the parameter alpha = 1.14 can be available from summer to autumn and alpha = to approximately 2.0 in winter. The results of the satellite and the airborne sensing done on 21st and 22nd January, 1983, are described. Using the vegetation distribution in the Tsukuba Academic New Town, as well as the radiation temperature obtained by remote sensing and the radiation data observed at the ground surface, the evapotranspiration was calculated for each vegetation type by the Priestley-Taylor method. The daily mean evapotranspiration on 22nd January, 1983, was approximately 0.4 mm/day. The differences in evapotranspiration between the vegetation types were not detectable, because the magnitude of evapotranspiration is very little in winter.

  10. Effects of Daily Precipitation and Evapotranspiration Patterns on Flow and VOC Transport to Groundwater along a Watershed Flow Path

    USGS Publications Warehouse

    Johnson, R.L.; Thoms, R.B.; Zogorski, J.S.

    2003-01-01

    MTBE and other volatile organic compounds (VOCs) are widely observed in shallow groundwater in the United States, especially in urban areas. Previous studies suggest that the atmosphere and/or nonpoint surficial sources could be responsible for some of those VOCs, especially in areas where there is net recharge to groundwater. However, in semiarid locations where annual potential evapotranspiration can exceed annual precipitation, VOC detections in groundwater can be frequent. VOC transport to groundwater under net discharge conditions has not previously been examined. A numerical model is used here to demonstrate that daily precipitation and evapotranspiration (ET) patterns can have a significant effect on recharge to groundwater, water table elevations, and VOC transport. Ten-year precipitation/ET scenarios from six sites in the United States are examined using both actual daily observed values and "average" pulsed precipitation. MTBE and tetrachloroethylene transport, including gas-phase diffusion, are considered. The effects of the precipitation/ET scenarios on net recharge and groundwater flow are significant and complicated, especially under low-precipitation conditions when pulsed precipitation can significantly underestimate transport to groundwater. In addition to precipitation and evapotranspiration effects, location of VOC entry into the subsurface within the watershed is important for transport in groundwater. This is caused by groundwater hydraulics at the watershed scale as well as variations in ET within the watershed. The model results indicate that it is important to consider both daily precipitation/ET patterns and location within the watershed in order to interpret VOC occurrence in groundwater, especially in low-precipitation settings.

  11. Retrospective forecast of ETAS model with daily parameters estimate

    NASA Astrophysics Data System (ADS)

    Falcone, Giuseppe; Murru, Maura; Console, Rodolfo; Marzocchi, Warner; Zhuang, Jiancang

    2016-04-01

    We present a retrospective ETAS (Epidemic Type of Aftershock Sequence) model based on the daily updating of free parameters during the background, the learning and the test phase of a seismic sequence. The idea was born after the 2011 Tohoku-Oki earthquake. The CSEP (Collaboratory for the Study of Earthquake Predictability) Center in Japan provided an appropriate testing benchmark for the five 1-day submitted models. Of all the models, only one was able to successfully predict the number of events that really happened. This result was verified using both the real time and the revised catalogs. The main cause of the failure was in the underestimation of the forecasted events, due to model parameters maintained fixed during the test. Moreover, the absence in the learning catalog of an event similar to the magnitude of the mainshock (M9.0), which drastically changed the seismicity in the area, made the learning parameters not suitable to describe the real seismicity. As an example of this methodological development we show the evolution of the model parameters during the last two strong seismic sequences in Italy: the 2009 L'Aquila and the 2012 Reggio Emilia episodes. The achievement of the model with daily updated parameters is compared with that of same model where the parameters remain fixed during the test time.

  12. The Three-dimensional Structure of the Eta Carinae Homunculus

    NASA Technical Reports Server (NTRS)

    Steffen, W.; Teodoro, M.; Madura, T.I.; Groh, J.H.; Gull, T.R.; Mehner, A.; Corcoran, M.F.; Damineli, A.; Hamaguchi, K.

    2014-01-01

    We investigate, using the modeling code SHAPE, the three-dimensional structure of the bipolar Homunculus nebula surrounding Eta Carinae as mapped by new ESO VLT/X-Shooter observations of the H2 (lambda) = 2.12125 micrometers emission line. Our results reveal for the first time important deviations from the axisymmetric bipolar morphology: 1) circumpolar trenches in each lobe positioned point-symmetrically from the center and 2) offplanar protrusions in the equatorial region from each lobe at longitudinal (approximately 55 degrees) and latitudinal (10 degrees to 20 degrees) distances from the projected apastron direction of the binary orbit. The angular distance between the protrusions (approximately 110 degrees) is similar to the angular extent of each polar trench (approximately 130 degrees) and nearly equal to the opening angle of the wind-wind collision cavity (approximately 110 degrees). As in previous studies, we confirm a hole near the centre of each polar lobe and no detectable near-IR H2 emission from the thin optical skirt seen prominently in visible imagery. We conclude that the interaction between the outflows and/or radiation from the central binary stars and their orientation in space has had, and possibly still has, a strong influence on the Homunculus. This implies that prevailing theoretical models of the Homunculus are incomplete as most assume a single star origin that produces an axisymmetric nebula.We discuss how the newly found features might be related to the Homunculus ejection, the central binary and the interacting stellar winds.

  13. The -145 km/s Absorption System of Eta Carinae

    NASA Astrophysics Data System (ADS)

    Vieira, G. L.; Gull, T. R.; Danks, A. C.; Johansson, S.

    2002-12-01

    With the STIS E230H mode (R 118,000), we have identified about twenty absorption components in line of sight from Eta Carinae. Two components, one at -513 km/s and another at -145 km/s, are quite different in character from the others, mostly at intermediate velocities (See adjacent posters by T. Gull and A. Danks). The -145 km/s component is significantly wider in fwhm, is seen in many more species, and the lower level can be above 20,000 cm-1, well above the 2000 cm-1 noted in the -513 km/s component. In the spectral region from 2400 to 3160A, approximately 500 absorption lines have been identified. In this poster, we will present line identifications and atomic parameters of the measured lines, hopefully providing insight as to what levels are being excited and by what processes. Observations were accomplished through STScI under proposal 9242 (Danks, P.I.). Funding is through the STIS GTO resources.

  14. Eta Carinae: At the Crossroads of becoming a Supernova

    NASA Technical Reports Server (NTRS)

    Gull, Theodore

    2007-01-01

    Since the 1840's, when Eta Carinae's visual magnitude rivaled Sirius, the brightest star in the night sky, astronomers have wondered what major event took place. Today with the Hubble Space Telescope Imaging Spectrograph, with CHANDRA X-ray spectroscopy and the Very Large Telescope spectrographs and interferometers, we have learned that over 12 solar masses of material was ejected at 500 to 700 km/s into interstellar space. This ejecta is quite different from the normal interstellar medium. It is rich in nitrogen, poor in oxygen and carbon. The dust properties are quite peculiar and many metals such as vanadium, strontium, cadmium are seen in both absorption against the central source, plus a number of molecules. The chemical and dust formation is likely dominated by nitrogen as we see H_2, CH, CH+, OH, NH, HCl and NH-3, but no CO. Other metals and molecules are being searched out in the FUSE, HST/STIS, VLT/UVES and VLT/CRIRES spectra. I will describe what we know about the massive binary stellar system, how it changes every 5.54 year in UV and X-ray output and how the massive ejecta responds in this astrophysical laboratory.

  15. Eta Carinae: an Update on the Integral Nebula

    NASA Astrophysics Data System (ADS)

    Gull, T. R.; Ishibashi, K.; Davidson, K.; Zethson, T.; Johannson, S.; Hartman, H.; Eta Carinae Cycle 7 and 8 Collaboration

    1999-12-01

    Observations of the ejecta associated with Eta Carinae were done using the Space Telescope Imaging Spectrograph (STIS) with CCD and grating settings yielding resolving power 5000 during four visits between December 1997 and February 1999. The identical position and position angle was utilized for the March 1998 and February 1999 observations that are continuous from 1640 to 10400A. In eleven months, considerable changes in nebular structure, nebular brightness, emission lines and absorption lines have taken place. Moreover, the nebular structures change rapidly on a scale of 0.1", the angular resolution of the STIS CCD. We have been systematically identifying both the emission lines and absorption lines present in the nebular spectrum. Multiple fluorescent lines are present and have changed considerably in intensity. Most notable is the change in iron ionization. Effectively the near ultraviolet transparency has increased due to conversion of much iron from Fe II to Fe III. This activity is funded by NASA through STIS GTO and STScI GO resources and through University of Lund, Sweden.

  16. CRITICAL DIFFERENCES AND CLUES IN ETA CAR'S 2009 EVENT ,

    SciTech Connect

    Mehner, Andrea; Davidson, Kris; Humphreys, Roberta M.; Martin, John C.; Ishibashi, Kazunori; Ferland, Gary J.

    2011-10-20

    We monitored Eta Carinae with the Hubble Space Telescope WFPC2 and Gemini GMOS throughout the 2009 spectroscopic event, which was expected to differ from its predecessor in 2003. Here we report major observed differences between events and their implications. Some of these results were quite unexpected. (1) The UV brightness minimum was much deeper in 2009. This suggests that physical conditions in the early stages of an event depend on different parameters than the 'normal' inter-event wind. Extra mass ejection from the primary star is one possible cause. (2) The expected He II {lambda}4687 brightness maximum was followed several weeks later by another. We explain why this fact and the timing of the {lambda}4687 maxima strongly support a 'shock breakup' hypothesis for X-ray and {lambda}4687 behavior as proposed 5-10 years ago. (3) We observed a polar view of the star via light reflected by dust in the Homunculus nebula. Surprisingly, at that location, the variations of emission-line brightness and Doppler velocities closely resembled a direct view of the star, which should not have been true for any phenomena related to the orbit. This result casts very serious doubt on all the proposed velocity interpretations that depend on the secondary star's orbital motion. (4) Latitude-dependent variations of H I, He I, and Fe II features reveal aspects of wind behavior during the event. In addition, we discuss implications of the observations for several crucial unsolved problems.

  17. Estimation of annual Groundwater Evapotranspiration from Phreatophyte Vegetation in the Great Basin using Remotely Sensed Vegetation Indices and Ground Based Flux Tower measurements

    NASA Astrophysics Data System (ADS)

    Beamer, Jordan P.

    Escalating concerns about the future of water resource management in arid regions of the American Southwest have sparked numerous hydrologic studies looking into available water resources for in-basin and inter-basin transfers. Groundwater is the primary water supply source for much of the state of Nevada and the Great Basin, thus accurate estimates of the regional scale groundwater recharge and discharge components are critical for regional groundwater budgets. Groundwater discharge from phreatophyte vegetation by evapotranspiration (ET) is the dominant component of groundwater discharge in many hydrologically closed valleys of the Great Basin, and can be measured directly from eddy-covariance (EC) and Bowen-ratio (BR) flux tower systems. The purpose of this project was to develop a predictive equation based on relationship between annual ET and meteorological data from EC and BR sites in phreatophyte vegetation with remote sensing data. Annual total ET (ET a) measured from forty site/year combinations of flux tower data from Carson Valley, Walker River Basin, Oasis Valley, Snake Valley, Spring Valley, White River Valley, and the lower Colorado River Flow system were correlated with the Enhanced Vegetation Index (EVI) from Landsat Thematic Mapper (TM) satellite. EVI was extracted from source areas at corresponding locations from 15 mid-summer Landsat TM scenes. ETa was transformed into ET* by subtracting annual precipitation and normalizing by annual reference ET (ETo) (ET*=(ETa-precipitation)/(ETo-precipitation)). ET* correlated well with EVI (r2=0.97), and because it takes basin specific climate measurements into account, it is transferable to many shallow groundwater discharge areas in the Great Basin. This relationship was used to provide a first order estimate of the mean annual groundwater ET (ETg) from four phreatophyte groundwater discharge areas in Nevada using only a mid-summer Landsat EVI image, annual ETo and precipitation data. This simple approach

  18. Estimating Spatially Variable Parameters of the Epidemic Type Aftershock Sequence (ETAS) in California

    NASA Astrophysics Data System (ADS)

    Nandan, Shyam; Ouillon, Guy; Sornette, Didier; Wiemer, Stefan

    2016-04-01

    The ETAS model is widely employed to model the spatio-temporal distribution of earthquakes, generally using spatially invariant parameters, which is most likely a gross simplification considering the extremely heterogeneous structure of the Earth's crust. We propose an efficient method for the estimation of spatially varying parameters, using an expectation maximization (EM) algorithm and spatial Voronoi tessellations. We assume that each Voronoi cell is characterized by a set of eight constant ETAS parameters. For a given number of randomly distributed cells, Vi=1 to N, we jointly invert the ETAS parameters within each cell using an EM algorithm. This process is progressively repeated several times for a given N (which controls the complexity), which is itself increased incrementally. We use the Bayesian Information Criterion (BIC) to rank all the inverted models given their likelihood and complexity and select the top 1% models to compute the average model at any location. Using a synthetic catalog, we also check that the proposed method correctly inverts the known parameters. We apply the proposed method to earthquakes (M>=3) included in the ANSS catalog that occurred within the time period 1981-2016 in the spatial polygon defined by RELM/CSEP around California. The results indicate significant spatial variation of the ETAS parameters. Using these spatially variable estimates of ETAS parameters, we are better equipped to answer some important questions: (1) What is the seismic hazard (both long- and short-term) in a given region? (2) What kind of earthquakes dominate triggering? (3) are there regions where earthquakes are most likely preceded by foreshocks? Last but not the least, a possible correlation of the spatially varying ETAS parameters with spatially variable geophysical properties can lead to an improved understanding of the physics of earthquake triggering beside providing physical meaning to the parameters of the purely statistical ETAS model.

  19. Gluon and charm content of the {eta}{sup {prime}} meson and instantons

    SciTech Connect

    Shuryak, E.V. |; Zhitnitsky, A.R. |

    1998-02-01

    Motivated by recent CLEO measurements of the B{r_arrow}{eta}{sup {prime}}K decay, we evaluate the gluon and charm content of the {eta}{sup {prime}} meson using the interacting instanton liquid model of the QCD vacuum. Our main result is {l_angle}0{vert_bar}g{sup 3}f{sup abc}G{sub {mu}{nu}}{sup a}{tilde G}{sub {nu}{alpha}}{sup b}G{sub {alpha}{mu}}{sup c}{vert_bar}{eta}{sup {prime}}{r_angle}={minus}(2.3{endash}3.3) GeV{sup 2}{times}{l_angle}0{vert_bar}g{sup 2}G{sub {mu}{nu}}{sup a}{tilde G}{sub {mu}{nu}}{sup a}{vert_bar}{eta}{sup {prime}}{r_angle}. It is very large due to the strong field of small-size instantons. We show that it provides quantitative explanations of the CLEO data on the B{r_arrow}{eta}{sup {prime}}K decay rate (as well as the inclusive process B{r_arrow}{eta}{sup {prime}}+X), via a virtual Cabibbo-unsuppressed decay into a {bar c}c pair which then becomes {eta}{sup {prime}}. If so, a significant charm component may be present in other hadrons also: We briefly discuss the contribution of the charmed quark to the {ital polarized} deep-inelastic scattering on a proton. {copyright} {ital 1998} {ital The American Physical Society}

  20. Latitude-Dependent Effects in the Stellar Wind of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Smith, Nathan; Davidson, Kris; Gull, Theodore R.; Ishibashi, Kazunori; Hillier, D. John

    2002-01-01

    The Homunculus reflection nebula around eta Carinae provides the rare opportunity to observe the spectrum of a star from more than one direction. In the case of eta Car, the nebula's geometry is known well enough to infer how wind profiles vary with latitude. We present STIS spectra of several positions in the Homunculus, showing directly that eta Car has an aspherical and axisymmetric stellar wind. P Cygni absorption in Balmer lines depends on latitude, with relatively high velocities and strong absorption near the polar axis. Stronger absorption at high latitudes is surprising, and it suggests higher mass flux toward the poles, perhaps resulting from equatorial gravity darkening on a rotating star. Reflected profiles of He I lines are more puzzling, and offer clues to eta Car's wind geometry and ionization structure. During eta Car's high-excitation state in March 2000, the wind had a fast, dense polar wind, with higher ionization at low latitudes. Older STIS data obtained since 1998 reveal that this global stellar-wind geometry changes during eta Car's 5.5 year cycle, and may suggest that this star s spectroscopic events are shell ejections. Whether or not a companion star triggers these outbursts remains ambiguous. The most dramatic changes in the wind occur at low latitudes, while the dense polar wind remains relatively undisturbed during an event. The apparent stability of the polar wind also supports the inferred bipolar geometry. The wind geometry and its variability have critical implications for understanding the 5.5 year cycle and long-term variability, but do not provide a clear alternative to the binary hypothesis for generating eta Car s X-rays.

  1. Effect of Enzyme-Treated Asparagus Extract (ETAS) on Psychological Stress in Healthy Individuals.

    PubMed

    Takanari, Jun; Nakahigashi, Jun; Sato, Atsuya; Waki, Hideaki; Miyazaki, Shogo; Uebaba, Kazuo; Hisajima, Tatsuya

    2016-01-01

    The aim of this study was to examine the effectiveness of Enzyme-Treated Asparagus Extract (ETAS) on improving stress response. A randomized, double-blind, placebo-controlled cross-over trial was undertaken in healthy volunteers. ETAS (150 mg/d) or a placebo was consumed for 28 d, with a washout period. Psychological parameters were examined using a self-report scale questionnaire and psychological stress was applied using the Uchida-Kraepelin (U-K) test. During the stress load, autonomic nervous function was analyzed. After the stress load, a profile of mood states (POMS) psychological rating was performed, and serum cortisol, plasma catecholamine, salivary secretory immunoglobulin A (sIgA), and salivary cortisol were analyzed. ETAS intake improved the self-reported rating for the items "Feel tired," "Hard to get up," and "Feel heavy" in the psychological questionnaire; ameliorated the self-reported rating for the items "Depression-Dejection" and "Fatigue" in the POMS questionnaire; and increased salivary sIgA levels after the U-K test. In contrast, serum and salivary cortisol levels, and plasma catecholamine did not change. During the U-K test, ETAS significantly upregulated the sympathetic nerve activity. Furthermore, ETAS intake significantly increased the number of answers and the number of correct answers in the U-K test, suggesting that it might improve office work performance with swiftness and accuracy under stressful conditions. In conclusion, ETAS supplementation reduced feelings of dysphoria and fatigue, ameliorated quality of sleep, and enhanced stress-load performance as well as promoted stress response by increasing salivary sIgA levels. These data suggest ETAS intake may exert beneficial effects, resulting from well-controlled stress management, in healthy individuals. PMID:27465727

  2. Uncertainty Quantification of Evapotranspiration and Infiltration from Modeling and Historic Time Series at the Savannah River F-Area

    NASA Astrophysics Data System (ADS)

    Faybishenko, B.; Flach, G. P.

    2012-12-01

    The objectives of this presentation are: (a) to illustrate the application of Monte Carlo and fuzzy-probabilistic approaches for uncertainty quantification (UQ) in predictions of potential evapotranspiration (PET), actual evapotranspiration (ET), and infiltration (I), using uncertain hydrological or meteorological time series data, and (b) to compare the results of these calculations with those from field measurements at the U.S. Department of Energy Savannah River Site (SRS), near Aiken, South Carolina, USA. The UQ calculations include the evaluation of aleatory (parameter uncertainty) and epistemic (model) uncertainties. The effect of aleatory uncertainty is expressed by assigning the probability distributions of input parameters, using historical monthly averaged data from the meteorological station at the SRS. The combined effect of aleatory and epistemic uncertainties on the UQ of PET, ET, and Iis then expressed by aggregating the results of calculations from multiple models using a p-box and fuzzy numbers. The uncertainty in PETis calculated using the Bair-Robertson, Blaney-Criddle, Caprio, Hargreaves-Samani, Hamon, Jensen-Haise, Linacre, Makkink, Priestly-Taylor, Penman, Penman-Monteith, Thornthwaite, and Turc models. Then, ET is calculated from the modified Budyko model, followed by calculations of I from the water balance equation. We show that probabilistic and fuzzy-probabilistic calculations using multiple models generate the PET, ET, and Idistributions, which are well within the range of field measurements. We also show that a selection of a subset of models can be used to constrain the uncertainty quantification of PET, ET, and I.

  3. A parabolic function to modify Thornthwaite estimates of potential evapotranspiration for the eastern United States

    USGS Publications Warehouse

    McCabe, G.J., Jr.

    1989-01-01

    Errors of the Thornthwaite model can be analyzed using adjusted pan evaporation as an index of potential evapotranspiration. An examination of ratios of adjusted pan evaporation to Thornthwaite potential evapotranspiration indicates that the ratios are highest in the winter and lowest during summer months. This trend suggests a parabolic pattern. In this study a parabolic function is used to adjust Thornthwaite estimates of potential evapotranspiration. Forty locations east of the Rocky Mountains are analyzed. -from Author

  4. Protein kinase C{eta} activates NF-{kappa}B in response to camptothecin-induced DNA damage

    SciTech Connect

    Raveh-Amit, Hadas; Hai, Naama; Rotem-Dai, Noa; Shahaf, Galit; Gopas, Jacob; Livneh, Etta

    2011-08-26

    Highlights: {yields} Protein kinase C-eta (PKC{eta}) is an upstream regulator of the NF-{kappa}B signaling pathway. {yields} PKC{eta} activates NF-{kappa}B in non-stressed conditions and in response to DNA damage. {yields} PKC{eta} regulates NF-{kappa}B by activating I{kappa}B kinase (IKK) and inducing I{kappa}B degradation. -- Abstract: The nuclear factor {kappa}B (NF-{kappa}B) family of transcription factors participates in the regulation of genes involved in innate- and adaptive-immune responses, cell death and inflammation. The involvement of the Protein kinase C (PKC) family in the regulation of NF-{kappa}B in inflammation and immune-related signaling has been extensively studied. However, not much is known on the role of PKC in NF-{kappa}B regulation in response to DNA damage. Here we demonstrate for the first time that PKC-eta (PKC{eta}) regulates NF-{kappa}B upstream signaling by activating the I{kappa}B kinase (IKK) and the degradation of I{kappa}B. Furthermore, PKC{eta} enhances the nuclear translocation and transactivation of NF-{kappa}B under non-stressed conditions and in response to the anticancer drug camptothecin. We and others have previously shown that PKC{eta} confers protection against DNA damage-induced apoptosis. Our present study suggests that PKC{eta} is involved in NF-{kappa}B signaling leading to drug resistance.

  5. Observation of eta_c(1S) and eta_c(2S) decays to K K-pi pi-pi0 in two-photon interactions

    SciTech Connect

    Sanchez, P.del Amo

    2011-05-20

    We study the processes {gamma}{gamma} {yields} K{sub S}{sup 0}K{sup {+-}}{pi}{sup {-+}} and {gamma}{gamma} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup 0} using a data sample of 519.2 fb{sup -1} recorded by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at center-of-mass energies near the {Upsilon}(nS) (n = 2, 3, 4) resonances. We observe the {eta}{sub c}(1S), {chi}{sub c0}(1P), {chi}{sub c2}(1P), and {eta}{sub c}(2S) resonances produced in two-photon interactions and decaying to K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup 0}, with significances of 18.1, 5.7, 5.2, and 5.3 standard deviations (including systematic errors), respectively. We measure the {eta}{sub c}(2S) mass and width in K{sub S}{sup 0}K{sup {+-}}{pi}{sup {-+}} decays, m({eta}{sub c}(2S)) = 3638.5 {+-} 1.5 {+-} 0.8 MeV/c{sup 2} and {Lambda}({eta}{sub c}(2S)) = 13.4 {+-} 4.6 {+-} 3.2 MeV, where the first uncertainty is statistical and the second is systematic. We search for the Z(3930) resonance and find no significant signal. We also provide the two-photon width times branching fraction values for the observed resonances.

  6. Estimating actual, potential, reference crop and pan evaporation using standard meteorological data: a pragmatic synthesis

    NASA Astrophysics Data System (ADS)

    McMahon, T. A.; Peel, M. C.; Lowe, L.; Srikanthan, R.; McVicar, T. R.

    2013-04-01

    This guide to estimating daily and monthly actual, potential, reference crop and pan evaporation covers topics that are of interest to researchers, consulting hydrologists and practicing engineers. Topics include estimating actual evaporation from deep lakes and from farm dams and for catchment water balance studies, estimating potential evaporation as input to rainfall-runoff models, and reference crop evapotranspiration for small irrigation areas, and for irrigation within large irrigation districts. Inspiration for this guide arose in response to the authors' experiences in reviewing research papers and consulting reports where estimation of the actual evaporation component in catchment and water balance studies was often inadequately handled. Practical guides using consistent terminology that cover both theory and practice are not readily available. Here we provide such a guide, which is divided into three parts. The first part provides background theory and an outline of the conceptual models of potential evaporation of Penman, Penman-Monteith and Priestley-Taylor, as well as discussions of reference crop evapotranspiration and Class-A pan evaporation. The last two sub-sections in this first part include techniques to estimate actual evaporation from (i) open-surface water and (ii) landscapes and catchments (Morton and the advection-aridity models). The second part addresses topics confronting a practicing hydrologist, e.g. estimating actual evaporation for deep lakes, shallow lakes and farm dams, lakes covered with vegetation, catchments, irrigation areas and bare soil. The third part addresses six related issues: (i) automatic (hard wired) calculation of evaporation estimates in commercial weather stations, (ii) evaporation estimates without wind data, (iii) at-site meteorological data, (iv) dealing with evaporation in a climate change environment, (v) 24 h versus day-light hour estimation of meteorological variables, and (vi) uncertainty in evaporation

  7. The sub-arcsecond dusty environment of Eta Carinae

    NASA Astrophysics Data System (ADS)

    Chesneau, O.; Min, M.; Herbst, T.; Waters, L. B. F. M.; Hillier, D. J.; Leinert, Ch.; de Koter, A.; Pascucci, I.; Jaffe, W.; Köhler, R.; Alvarez, C.; van Boekel, R.; Brandner, W.; Graser, U.; Lagrange, A. M.; Lenzen, R.; Morel, S.; Schöller, M.

    2005-06-01

    The core of the nebula surrounding Eta Carinae has been observed with the VLT Adaptive Optics system NACO and with the interferometer VLTI/MIDI to constrain spatially and spectrally the warm dusty environment and the central object. In particular, narrow-band images at 3.74 μm and 4.05 μm reveal the butterfly shaped dusty environment close to the central star with unprecedented spatial resolution. A void whose radius corresponds to the expected sublimation radius has been discovered around the central source. Fringes have been obtained in the Mid-IR which reveal a correlated flux of about 100 Jy situated 0.3 arcsec south-east of the photocenter of the nebula at 8.7 μm, which corresponds with the location of the star as seen in other wavelengths. This correlated flux is partly attributed to the central object, and these observations provide an upper limit for the SED of the central source from 2.2 μm to 13.5 μm. Moreover, we have been able to spectrally disperse the signal from the nebula itself at PA = 318 degree, i.e. in the direction of the bipolar nebula (~310°) within the MIDI field of view of 3 arcsec. A large amount of corundum (Al2O3) is discovered, peaking at 0.6 arcsec-1.2 arcsec south-east from the star, whereas the dust content of the Weigelt blobs is dominated by silicates. We discuss the mechanisms of dust formation which are closely related to the geometry of this Butterfly nebulae.

  8. The Strontium Filament within the Homunculus of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Hartman, H.; Zethson, T.; Johansson, S.; Ishibashi, K.; Davidson, K.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    During a series of HST/STIS observations of Eta Carinae and associated ejecta, we noticed a peculiar emission filament located a few arcseconds north of the central source. While bright in nebular standards, it is submerged in a sea of scattered starlight until moderately high dispersion, long-slit spectroscopy with the STIS (R- 8000) brings the emission lines out. The initial spectrum, centered on 6768A with the STIS G750M grating, led to identification of twenty lines from singly-Ionized species including [Sr II], [Fe II], [Ti II], [Ni II], [Mn II], and [Co II] (Zethson, etal., 2001, AJ 122,322). No Balmer emission is detected from this filament and the Fe II 2507,9 lines, known to be pumped by Lyman alpha radiation in other regions near the central source, are not detected. Followup observations have led to detection of hundreds more emission lines from iron group elements in neutral and singly-ionized states. Thus far all are excited by less than 10 eV. This peculiar nebular emission is thought to be due to very intense stellar radiation, stripped of uv flux shortward of Lyman alpha, bathing a neutral structure. We are systematically identifying the many lines (over 90% identified) and measuring line intensities that will then be modeled to determine excitation mechanisms, temperature and density. Two [Sr II] and two Sr II lines have now been measured. Bautista, etal. (in preparation) have modeled the strontium flux ratios and find that large radiation fluxes and/or high strontium abundances may account for the detected emission. These observations were supported by STIS GTO funding and GO funding through the STScI

  9. Eta Carinae and the Homunculus: An Astrophysical Laboratory

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.

    2006-01-01

    High spatial resolution spectroscopy with HST/STIS between 1998.0 and 2004.2 has provided much exciting information about the central binary system and the physics of its N-rich, C,O-poor ejecta. Stellar He I profiles, noticeably blue-shifted relative to P Cygni H and Fe II line profiles, originate from the ionized wind region between two massive companions. Changes in profiles of He I singlet and triplet lines provide clues to the excitation mechanisms involved as the hot, UV companion moves in its highly eccentric orbit. For 90% of the 5.54-year period, the spectra of nearby Weigelt blobs and the Little Homunculus include highly excited emission lines of Ar, Ne, and Fe. During the few month-long spectroscopic minimum, these systems are deprived of Lyman continuum. Recombination, plus cooling, occurs. In the skirt region between the bipolar Homunculus, a neutral emission region, devoid of hydrogen emission, glows in Ti II, Fe I, Sr II, Sc II, etc. We find the ejecta to have Ti/Ni abundances nearly 100 times solar, not due to nuclear processing, but due to lack of oxygen. Many metals normally tied up in interstellar dust remain in gaseous phase. Much information is being obtained on the physical processes in these warm N-rich gases, whose excitation varies with time in a predictable pattern. Indeed recent GRB high dispersion spectra include signatures of circumGRB warm gases. This indicates that the early, primordial massive stars have warm massive ejecta reminiscent to that around Eta Carinae.

  10. Eta Carinae and the Homunculus: an Astrophysical Laboratory

    NASA Astrophysics Data System (ADS)

    Gull, T. R.

    2007-08-01

    High spatial resolution spectroscopy with HST/STIS between 1998.0 and 2004.2 has provided much exciting information about the central binary system and the physics of its N-rich, C,O-poor ejecta. Stellar He I profiles, noticeably blue-shifted relative to P Cygni H and Fe II line profiles, originate from the ionized wind region between two massive companions. Changes in profiles of He I singlet and triplet lines provide clues to the excitation mechanisms involved as the hot, UV companion moves in its highly eccentric orbit. For 90% of the 5.54-year period, the spectra of nearby Weigelt blobs and the Little Homunculus include highly excited emission lines of Ar, Ne, and Fe. During the few month-long spectroscopic minimum, these systems are deprived of Lyman continuum. Recombination, plus cooling, occurs. In the skirt region between the bipolar Homunculus, a neutral emission region, devoid of hydrogen emission, glows in Ti II, Fe I, Sr II, Sc II, etc. We find the ejecta to have Ti/Ni abundances nearly 100 times solar, not due to nuclear processing, but due to lack of oxygen. Many metals normally tied up in interstellar dust remain in gaseous phase. Much information is being obtained on the physical processes in these warm N-rich gases, whose excitation varies with time in a predictable pattern. Indeed recent GRB high dispersion spectra include signatures of circumGRB warm gases. This indicates that the early, primordial massive stars have warm massive ejecta reminiscent to that around Eta Carinae.

  11. Critical Differences and Clues in Eta Car's 2009 Event

    NASA Astrophysics Data System (ADS)

    Mehner, Andrea; Davidson, Kris; Martin, John C.; Humphreys, Roberta M.; Ishibashi, Kazunori; Ferland, Gary J.

    2011-10-01

    We monitored Eta Carinae with the Hubble Space Telescope WFPC2 and Gemini GMOS throughout the 2009 spectroscopic event, which was expected to differ from its predecessor in 2003. Here we report major observed differences between events and their implications. Some of these results were quite unexpected. (1) The UV brightness minimum was much deeper in 2009. This suggests that physical conditions in the early stages of an event depend on different parameters than the "normal" inter-event wind. Extra mass ejection from the primary star is one possible cause. (2) The expected He II λ4687 brightness maximum was followed several weeks later by another. We explain why this fact and the timing of the λ4687 maxima strongly support a "shock breakup" hypothesis for X-ray and λ4687 behavior as proposed 5-10 years ago. (3) We observed a polar view of the star via light reflected by dust in the Homunculus nebula. Surprisingly, at that location, the variations of emission-line brightness and Doppler velocities closely resembled a direct view of the star, which should not have been true for any phenomena related to the orbit. This result casts very serious doubt on all the proposed velocity interpretations that depend on the secondary star's orbital motion. (4) Latitude-dependent variations of H I, He I, and Fe II features reveal aspects of wind behavior during the event. In addition, we discuss implications of the observations for several crucial unsolved problems. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership. Based on observations made with the NASA/ESA Hubble Space Telescope. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under the NASA contract NAS 5-26555.

  12. The three-dimensional structure of the Eta Carinae Homunculus

    NASA Astrophysics Data System (ADS)

    Steffen, W.; Teodoro, M.; Madura, T. I.; Groh, J. H.; Gull, T. R.; Mehner, A.; Corcoran, M. F.; Damineli, A.; Hamaguchi, K.

    2014-08-01

    We investigate, using the modelling code SHAPE, the three-dimensional structure of the bipolar Homunculus nebula surrounding Eta Carinae as mapped by new ESO Very Large Telescope/X-Shooter observations of the H2 λ = 2.121 25 μm emission line. Our results reveal for the first time important deviations from the axisymmetric bipolar morphology: (1) circumpolar trenches in each lobe positioned point symmetrically from the centre and (2) off-planar protrusions in the equatorial region from each lobe at longitudinal (˜55°) and latitudinal (10°-20°) distances from the projected apastron direction of the binary orbit. The angular distance between the protrusions (˜110°) is similar to the angular extent of each polar trench (˜130°) and nearly equal to the opening angle of the wind-wind collision cavity (˜110°). As in previous studies, we confirm a hole near the centre of each polar lobe and no detectable near-IR H2 emission from the thin optical skirt seen prominently in visible imagery. We conclude that the interaction between the outflows and/or radiation from the central binary stars and their orientation in space has had, and possibly still has, a strong influence on the Homunculus. This implies that prevailing theoretical models of the Homunculus are incomplete as most assume a single-star origin that produces an axisymmetric nebula. We discuss how the newly found features might be related to the Homunculus ejection, the central binary, and the interacting stellar winds.

  13. DNA damage targets PKC{eta} to the nuclear membrane via its C1b domain

    SciTech Connect

    Tamarkin, Ana; Zurgil, Udi; Braiman, Alex; Hai, Naama; Krasnitsky, Ella; Maissel, Adva; Ben-Ari, Assaf; Yankelovich, Liat; Livneh, Etta

    2011-06-10

    Translocation to cellular membranes is one of the hallmarks of PKC activation, occurring as a result of the generation of lipid secondary messengers in target membrane compartments. The activation-induced translocation of PKCs and binding to membranes is largely directed by their regulatory domains. We have previously reported that PKC{eta}, a member of the novel subfamily and an epithelial specific isoform, is localized at the cytoplasm and ER/Golgi and is translocated to the plasma membrane and the nuclear envelope upon short-term activation by PMA. Here we show that PKC{eta} is shuttling between the cytoplasm and the nucleus and that upon etoposide induced DNA damage is tethered at the nuclear envelope. Although PKC{eta} expression and its phosphorylation on the hydrophobic motif (Ser675) are increased by etoposide, this phosphorylation is not required for its accumulation at the nuclear envelope. Moreover, we demonstrate that the C1b domain is sufficient for translocation to the nuclear envelope. We further show that, similar to full-length PKC{eta}, the C1b domain could also confer protection against etoposide-induced cell death. Our studies demonstrate translocation of PKC{eta} to the nuclear envelope, and suggest that its spatial regulation could be important for its cellular functions including effects on cell death.

  14. Eta Car: The Good, the Bad and the Ugly of Nebular and Stellar Confusion

    NASA Technical Reports Server (NTRS)

    Gull, T.R.; Sonneborn, G.; Jensen, A.G.; Nielsen, K.E.; Vieira Kover, G.; Hillier, D.J.

    2008-01-01

    Observations in the far-UV provide a unique opportunity to investigate the very massive star Eta Car and its hot binary companion, Eta Car B. Eta Car was observed with FUSE over a large portion of the 5.54 year spectroscopic period before and after the 2003.5 minimum. The observed spectrum is defined by strong stellar wind signatures, primarily from Eta Car A, complicated by the strong absorptions of the ejecta surrounding Eta Car plus interstellar absorption. The Homunculus and Little Homunculus are massive bipolar ejecta historically associable with LBV outbursts in the 1840s and the 1890s and are linked to absorptions at -513 and -146 km/s, respectively. The FUSE spectra are confused by the extended nebulosity and thermal drifting of the FUSE co-pointed instruments. Interpretation is further complicated by two B-stars sufficiently close to h Car to be included most of the time in the large FUSE aperture. Followup observations partially succeeded in obtaining spectra of at least one of these B-stars through the smaller apertures, allowing potential separation of the B-star contributions and h Car. A complete analysis of all available spectra is currently underway. Our ultimate goals are to directly detect the hot secondary star if possible with FUSE and to identify the absorption contributions to the overall spectrum especially of the stellar members and the massive ejecta.

  15. Eta photoproduction in a combined analysis of pion- and photon-induced reactions

    SciTech Connect

    Ronchen, D.; Doring, M.; Haberzettl, H.; Haidenbauer, J.; MeiBner, U. -G.; Nakayama, K.

    2015-06-25

    The $\\eta N$ final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited $\\Delta$ states. To this end, the world database on eta photoproduction off the proton up to a center-of-mass energy of $E\\sim 2.3$ GeV is analyzed, including data on differential cross sections, and single and double polarization observables. The resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions $\\pi N\\to \\pi N$, $\\eta N$, $K\\Lambda$ and $K\\Sigma$. For the analysis, the so-called J\\"ulich coupled-channel framework is used, incorporating unitarity, analyticity, and effective three-body channels. Parameters tied to photoproduction and hadronic interactions are varied simultaneously. Furthermore, the influence of recent MAMI $T$ and $F$ asymmetry data on the eta photoproduction amplitude is discussed in detail.

  16. Eta photoproduction in a combined analysis of pion- and photon-induced reactions

    DOE PAGESBeta

    Ronchen, D.; Doring, M.; Haberzettl, H.; Haidenbauer, J.; MeiBner, U. -G.; Nakayama, K.

    2015-06-25

    Themore » $$\\eta N$$ final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited $$\\Delta$$ states. To this end, the world database on eta photoproduction off the proton up to a center-of-mass energy of $$E\\sim 2.3$$ GeV is analyzed, including data on differential cross sections, and single and double polarization observables. resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions $$\\pi N\\to \\pi N$$, $$\\eta N$$, $$K\\Lambda$$ and $$K\\Sigma$$. For the analysis, the so-called J\\"ulich coupled-channel framework is used, incorporating unitarity, analyticity, and effective three-body channels. Parameters tied to photoproduction and hadronic interactions are varied simultaneously. Furthermore, the influence of recent MAMI $T$ and $F$ asymmetry data on the eta photoproduction amplitude is discussed in detail.« less

  17. Branching Fractions and CP-Violating Asymmetries in Radiative B Decays to eta K gamma

    SciTech Connect

    Aubert, B.

    2008-05-14

    The authors present measurements of the CP-violation parameters S and C for the radiative decay B{sup 0} {yields} {eta}K{sub S}{sup 0}{gamma}; for B {yields} {eta}K{gamma} they also measure the branching fractions and for B{sup +} {yields} {eta}K{sup +}{gamma} the time-integrated charge asymmetry {Alpha}{sub ch}. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465 x 10{sup 6} B{bar B} pairs produced in e{sup +}e{sup -} annihilation. The results are S = -0.18{sub -0.46}{sup +0.49} {+-} 0.12, C = -0.32{sub -0.39}{sup +0.40} {+-} 0.07, {Beta}(B{sup 0} {yields} {eta}K{sup 0}{gamma}) = (7.1{sub -2.0}{sup +2.1} {+-} 0.4) x 10{sup -6}, {Beta}(B{sup +} {yields} {eta}K{sup +}{gamma}) = (7.7 {+-} 1.0 {+-} 0.4) x 10{sup -6}, and {Alpha}{sub ch} = (-9.0{sub -9.8}{sup +10.4} {+-} 1.4) x 10{sup -2}. The first error quoted is statistical and the second systematic.

  18. Evidence for the eta(b)(1S) meson in radiative Upsilon(2S) decay.

    PubMed

    Aubert, B; Bona, M; Karyotakis, Y; Lees, J P; Poireau, V; Prencipe, E; Prudent, X; Tisserand, V; Garra Tico, J; Grauges, E; Lopez, L; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Battaglia, M; Brown, D N; Kerth, L T; Kolomensky, Yu G; Lynch, G; Osipenkov, I L; Tackmann, K; Tanabe, T; Hawkes, C M; Soni, N; Watson, A T; Koch, H; Schroeder, T; Asgeirsson, D J; Fulsom, B G; Hearty, C; Mattison, T S; McKenna, J A; Barrett, M; Khan, A; Randle-Conde, A; Blinov, V E; Bukin, A D; Buzykaev, A R; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Martin, E C; Stoker, D P; Abachi, S; Buchanan, C; Atmacan, H; Gary, J W; Liu, F; Long, O; Vitug, G M; Yasin, Z; Zhang, L; Sharma, V; Campagnari, C; Hong, T M; Kovalskyi, D; Mazur, M A; Richman, J D; Beck, T W; Eisner, A M; Heusch, C A; Kroseberg, J; Lockman, W S; Martinez, A J; Schalk, T; Schumm, B A; Seiden, A; Winstrom, L O; Cheng, C H; Doll, D A; Echenard, B; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Andreassen, R; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Bloom, P C; Ford, W T; Gaz, A; Hirschauer, J F; Nagel, M; Nauenberg, U; Smith, J G; Wagner, S R; Ayad, R; Soffer, A; Toki, W H; Wilson, R J; Feltresi, E; Hauke, A; Jasper, H; Karbach, M; Merkel, J; Petzold, A; Spaan, B; Wacker, K; Kobel, M J; Nogowski, R; Schubert, K R; Schwierz, R; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Verderi, M; Clark, P J; Playfer, S; Watson, J E; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cecchi, A; Cibinetto, G; Franchini, P; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Santoro, V; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Contri, R; Lo Vetere, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Tosi, S; Chaisanguanthum, K S; Morii, M; Adametz, A; Marks, J; Schenk, S; Uwer, U; Bernlochner, F U; Klose, V; Lacker, H M; Bard, D J; Dauncey, P D; Tibbetts, M; Behera, P K; Chai, X; Charles, M J; Mallik, U; Cochran, J; Crawley, H B; Dong, L; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gao, Y Y; Gritsan, A V; Guo, Z J; Arnaud, N; Béquilleux, J; D'Orazio, A; Davier, M; Firmino da Costa, J; Grosdidier, G; Le Diberder, F; Lepeltier, V; Lutz, A M; Pruvot, S; Roudeau, P; Schune, M H; Serrano, J; Sordini, V; Stocchi, A; Wormser, G; Lange, D J; Wright, D M; Bingham, I; Burke, J P; Chavez, C A; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Payne, D J; Touramanis, C; Bevan, A J; Clarke, C K; Di Lodovico, F; Sacco, R; Sigamani, M; Cowan, G; Paramesvaran, S; Wren, A C; Brown, D N; Davis, C L; Denig, A G; Fritsch, M; Gradl, W; Alwyn, K E; Bailey, D; Barlow, R J; Jackson, G; Lafferty, G D; West, T J; Yi, J I; Anderson, J; Chen, C; Jawahery, A; Roberts, D A; Simi, G; Tuggle, J M; Dallapiccola, C; Salvati, E; Saremi, S; Cowan, R; Dujmic, D; Fisher, P H; Henderson, S W; Sciolla, G; Spitznagel, M; Taylor, F; Yamamoto, R K; Zhao, M; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Godang, R; Kroeger, R; Summers, D J; Zhao, H W; Simard, M; Taras, P; Nicholson, H; De Nardo, G; Lista, L; Monorchio, D; Onorato, G; Sciacca, C; Raven, G; Snoek, H L; Jessop, C P; Knoepfel, K J; Losecco, J M; Wang, W F; Corwin, L A; Honscheid, K; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Sekula, S J; Wong, Q K; Blount, N L; Brau, J; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Castelli, G; Gagliardi, N; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Del Amo Sanchez, P; Ben-Haim, E; Briand, H; Chauveau, J; Hamon, O; Leruste, Ph; Ocariz, J; Perez, A; Prendki, J; Sitt, S; Gladney, L; Biasini, M; Manoni, E; Angelini, C; Batignani, G; Bettarini, S; Calderini, G; Carpinelli, M; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Lopes Pegna, D; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Anulli, F; Baracchini, E; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Jackson, P D; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Renga, F; Voena, C; Ebert, M; Hartmann, T; Schröder, H; Waldi, R; Adye, T; Franek, B; Olaiya, E O; Wilson, F F; Emery, S; Esteve, L; Hamel de Monchenault, G; Kozanecki, W; Vasseur, G; Yèche, Ch; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; White, R M; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Benitez, J F; Cenci, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dunwoodie, W; Field, R C; Gabareen, A M; Graham, M T; Grenier, P; Hast, C; Innes, W R; Kaminski, J; Kelsey, M H; Kim, H; Kim, P; Kocian, M L; Leith, D W G S; Li, S; Lindquist, B; Luitz, S; Luth, V; Lynch, H L; Macfarlane, D B; Marsiske, H; Messner, R; Muller, D R; Neal, H; Nelson, S; O'Grady, C P; Ofte, I; Perl, M; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Va'vra, J; Wagner, A P; Weaver, M; West, C A; Wisniewski, W J; Wittgen, M; Wright, D H; Wulsin, H W; Yarritu, A K; Yi, K; Young, C C; Ziegler, V; Burchat, P R; Edwards, A J; Miyashita, T S; Ahmed, S; Alam, M S; Ernst, J A; Pan, B; Saeed, M A; Zain, S B; Spanier, S M; Wogsland, B J; Eckmann, R; Ritchie, J L; Ruland, A M; Schilling, C J; Schwitters, R F; Drummond, B W; Izen, J M; Lou, X C; Bianchi, F; Gamba, D; Pelliccioni, M; Bomben, M; Bosisio, L; Cartaro, C; Della Ricca, G; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martinez-Vidal, F; Milanes, D A; Oyanguren, A; Albert, J; Banerjee, Sw; Bhuyan, B; Choi, H H F; Hamano, K; King, G J; Kowalewski, R; Lewczuk, M J; Nugent, I M; Roney, J M; Sobie, R J; Gershon, T J; Harrison, P F; Ilic, J; Latham, T E; Mohanty, G B; Puccio, E M T; Band, H R; Chen, X; Dasu, S; Flood, K T; Pan, Y; Prepost, R; Vuosalo, C O; Wu, S L

    2009-10-16

    We have performed a search for the eta_{b}(1S) meson in the radiative decay of the Upsilon(2S) resonance using a sample of 91.6x10(6) Upsilon(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at Egamma=609.3(-4.5)(+4.6)(stat)+/-1.9(syst) MeV, corresponding to an eta(b)(1S) mass of 9394.2(-4.9)(+4.8)(stat)+/-2.0(syst) MeV/c2. The branching fraction for the decay Upsilon(2S)-->gamma(eta)b(1S) is determined to be [3.9+/-1.1(stat)-0.9+1.1(syst)]x10(-4). We find the ratio of branching fractions B[Upsilon(2S)-->gamma(eta)b(1S)]/B[Upsilon(3S)-->gamma(eta)b(1S)]=0.82+/-0.24(stat)(-0.19)(+0.20)(syst). PMID:19905689

  19. The DARHT Scattering Wire Spectrometer: Operation and Checkout on ETA II

    SciTech Connect

    Fessenden, T J

    2005-03-09

    The DARHT Scattering wire energy spectrometer has been realized and checked out on ETA II. The ETA II beam energy is generally around 5.3 MeV. This value varies from pulse-to-pulse by around 0.5% and from month-to-month by as much as 6%. The energy acceptance of the spectrometer is {+-} 5% and the time response is less than 10 ns. The instrument was calibrated to enable absolute measurements of the ETA II beam energy accurate to {+-}3%. The beam energy in MeV is related to the bending magnetic field B{sub kG} according to E{sub MeV} = 0.511[{radical}(1+347.2B{sub kG}{sup 2}) -1]. The major difficulty encountered was in the development of detectors for the scattered electrons passing through the instrument. Fortunately one detector was fabricated that worked satisfactorily which enabled us to complete the tests on ETA II. The ETA II experiments and initial FXR experiments suggest that spurious X-ray signals will not prove troublesome. No results are yet available in the x-ray environment of DARHT.

  20. Episodic post-shock dust formation in the colliding winds of Eta Carinae

    NASA Astrophysics Data System (ADS)

    Smith, Nathan

    2010-02-01

    Eta Carinae shows broad peaks in near-infrared (IR) JHKL photometry, roughly correlated with times of periastron passage in the eccentric binary system. After correcting for secular changes attributed to reduced extinction from the thinning Homunculus nebula, these peaks have IR spectral energy distributions (SEDs) consistent with emission from hot dust at 1400-1700 K. The excess SEDs are clearly inconsistent, however, with the excess being entirely due to free-free wind or photospheric emission. One must conclude, therefore, that the broad near-IR peaks associated with Eta Carinae's 5.5yr variability are due to thermal emission from hot dust. I propose that this transient hot dust results from episodic formation of grains within compressed post-shock zones of the colliding winds, analogous to the episodic dust formation in Wolf-Rayet (WR) binary systems like WR 140 or the post-shock dust formation seen in some supernovae like SN 2006jc. This dust formation in Eta Carinae seems to occur preferentially near and after periastron passage; near-IR excess emission then fades as the new dust disperses and cools. With the high grain temperatures and Eta Car's C-poor abundances, the grains are probably composed of corundum or similar species that condense at high temperatures, rather than silicates or graphite. Episodic dust formation in Eta Car's colliding winds significantly impacts our understanding of the system, and several observable consequences are discussed.

  1. Swift Observations of the Recent X-ray Activity of Eta Carinae

    NASA Astrophysics Data System (ADS)

    Kalil Liburd, Jamar; Corcoran, Michael F.; Morris, David C.; Theodore Gull, Kenji Hamaguchi, Thomas Madura, Mairan Teodoro, Nick Durofchalk, Caleb Gimar.

    2015-01-01

    The extremely massive Luminous Blue Variable binary star, Eta Carinae, lies 7,500 light years away, deep within the Homunculus nebula where vigorous Wind-Wind collisions between the primary star and the companion star generate high-energy gases that produce X-rays. Complex X-ray variations occur near periastron, the point of least stellar separation between the two stars. Understanding the variability in Eta Carinae's high-energy spectrum during this period gives us a better understanding of the system's physical and stellar properties. We present the processing techniques and background estimation methods used to process and analyze weekly observations done with Swift's X-ray Telescope during Eta Carinae's most recent periastron passage in 2014. We present analysis of Eta Carinae's current column density and compare it to that of previous cycles. The exact nature of Eta Carinae's X-ray minimum activity, which occurs every 5.54 years, is still unclear. A detailed understanding of the mechanisms of the X-ray deep minimum stage and the associated differences in column density in each cycle will contribute to a clearer understanding of the wind-driven mass-loss from this unique system.

  2. Study of {pi}{sup -}p{yields}{pi}{sup -{eta}p} and {pi}{sup -}p{yields}{pi}{sup -{eta}{eta}}p at {radical}(s) = 18.9 GeV with the COMPASS experiment

    SciTech Connect

    Uman, I.; Schlueter, T.

    2010-08-05

    The COMPASS experiment at CERN studies diffractively produced states in the light quark sector with unprecedented statistics. The observation of f{sub 0}(1500)/f{sub 2}'(1525) decaying to {eta}{eta} in 2008 data with incoming negative pion beam at 190 GeV/c poses the question whether it is produced centrally or formed by the decay of a heavier diffractively produced {pi}{sub 1}(1800)/{pi}{sub 2}(1880). To decide, a dedicated amplitude analysis which includes different production mechanisms is formulated and compared with one which was used to fit centrally produced resonances including f{sub 0}(1500) by the WA102 experiment. Unbinned mass-dependent log-likelihood fitting methods may serve to solve the ambiguities which are present in binned, mass-independent partial wave analyses.

  3. Comparison of evapotranspiration rates for flatwoods and ridge citrus

    USGS Publications Warehouse

    Jia, X.; Swancar, A.; Jacobs, J.M.; Dukes, M.D.; Morgan, K.

    2007-01-01

    Florida citrus groves are typically grown in two regions of the state: flatwoods and ridge. The southern flatwoods citrus area has poorly drained fine textured sands with low organic matter in the shallow root zone. Ridge citrus is located in the northern ridge citrus zone and has fine to coarse textured sands with low water-holding capacity. Two commercial citrus groves, selected from each region, were studied from 15 July 2004 to 14 July 2005. The flatwoods citrus (FC) grove had a grass cover and used drainage ditches to remove excess water from the root zone. The ridge citrus (RC) grove had a bare soil surface with weeds periodically eliminated by tillage. Citrus crop evapotranspiration (ETc) rates at the two citrus groves were measured by the eddy correlation method, and components in the energy balance were also examined and compared. The study period had higher than average rainfall, and as a result, the two locations had similar annual ETc rates (1069 and 1044 mm for RC and FC, respectively). The ETc rates were 59% (RC) and 47% (FC) of the rainfall amounts during the study period. The annual reference crop evapotranspiration (ETo) rates were 1180 mm for RC and 1419 mm for FC, estimated using the standardized reference evapotranspiration equation. The citrus crop coefficients (Kc, ratio of ETc to ET o) were different between the two locations because of differences in latitude, ground cover, and rainfall amounts. The Kc values ranged from 0.70 between December and March to 1.05 between July and November for RC, and from 0.65 between November and May to 0.85 between June and October for FC. The results are consistent with other Kc values reported from field studies on citrus in both Florida and elsewhere using these and alternate methods.

  4. Seasonal water storage and delayed evapotranspiration across continents: Patterns and drivers

    NASA Astrophysics Data System (ADS)

    Kuppel, Sylvain; Fan, Ying; Jobbagy, Esteban

    2016-04-01

    Storage and delayed evapotranspiration (ET) of precipitation (P) inputs by land ecosystems is critical regulating the timing and stability of plant production and the multiple ecological and economic processes that it supports. The extent to which actual ET (AET) can decouple from P inputs depends on the ecohydrologic system capacity to store water. This decoupling and its associated storage requirement can be particularly relevant at the seasonal scale in regions where, for instance, rainfalls are highly seasonal and/or P and potential ET (PET) are seasonally out of phase. Focusing on the 2003-2010 period, we explore, first, where on Earth this decoupling is likely to occur from a climate perspective by assessing the magnitude and duration of the expected seasonal land water transfers. These climate-based predictions are then compared with independent evidence derived from satellite observations of vegetation activity (MODIS) and water storage (GRACE), together with datasets of terrain attributes. We assess how land surface processes alter the "potential" seasonal hydrologic buffer provided by the local climatic conditions, in terms of volume and residence time. This analysis helps outlining the expected seasonal response of the land water cycle in the frame of likely climate and land use changes.

  5. Direct Measurement of Daily Evapotranspiration From a Deciduous Forest Using a Superconducting Gravimeter

    NASA Astrophysics Data System (ADS)

    Van Camp, M. J.; de Viron, O.; Pajot-Métivier, G.; Cazenave, F.; Watlet, A.; Dassargues, A.; Vanclooster, M.

    2015-12-01

    The conversion of liquid water into water vapor strongly controls the energy transfer between the Earth and the atmosphere, and plays one of the most important roles in the hydrological cycle. This process, called evapotranspiration (ET), deeply constraints the amount of green water in the total global water balance. However, assessing the ET from terrestrial ecosystems remains a key challenge in hydrology. We show that the liquid water mass losses can be directly inferred from continuous gravity measurements: as water evaporates and transpires from terrestrial ecosystems, the mass distribution varies through the system, changing its gravity field. Using continuous superconducting gravity measurements, we were able to identify a daily changes in gravity at the level of, or smaller than 10-10 g per day. This corresponds to 2.0 mm of water over an area of 50 ha.The strength of this method is its ability to ensure a direct, traceable and continuous monitoring of actual ET for years at the mesoscale (~50 ha) with a precision of a few tenths of mm of water. This paves the way for the development of the method in different land-use, land-cover and geological contexts, using superconducting and coming quantum gravimeters.

  6. Estimating basin scale evapotranspiration (ET) by water balance and remote sensing methods

    USGS Publications Warehouse

    Senay, G.B.; Leake, S.; Nagler, P.L.; Artan, G.; Dickinson, J.; Cordova, J.T.; Glenn, E.P.

    2011-01-01

    Evapotranspiration (ET) is an important hydrological process that can be studied and estimated at multiple spatial scales ranging from a leaf to a river basin. We present a review of methods in estimating basin scale ET and its applications in understanding basin water balance dynamics. The review focuses on two aspects of ET: (i) how the basin scale water balance approach is used to estimate ET; and (ii) how ‘direct’ measurement and modelling approaches are used to estimate basin scale ET. Obviously, the basin water balance-based ET requires the availability of good precipitation and discharge data to calculate ET as a residual on longer time scales (annual) where net storage changes are assumed to be negligible. ET estimated from such a basin water balance principle is generally used for validating the performance of ET models. On the other hand, many of the direct estimation methods involve the use of remotely sensed data to estimate spatially explicit ET and use basin-wide averaging to estimate basin scale ET. The direct methods can be grouped into soil moisture balance modelling, satellite-based vegetation index methods, and methods based on satellite land surface temperature measurements that convert potential ET into actual ET using a proportionality relationship. The review also includes the use of complementary ET estimation principles for large area applications. The review identifies the need to compare and evaluate the different ET approaches using standard data sets in basins covering different hydro-climatic regions of the world.

  7. Estimation of Spatially Distributed Evapotranspiration Using Remote Sensing and a Relevance Vector Machine

    NASA Astrophysics Data System (ADS)

    Maslova, I.; Bachour, R.; Walker, W. R.; Ticlavilca, A. M.; McKee, M.

    2014-12-01

    With the development of surface energy balance analyses, remote sensing has become a spatially explicit and quantitative methodology for understanding evapotranspiration (ET), a critical requirement for water resources planning and management. Limited temporal resolution of satellite images and cloudy skies present major limitations that impede continuous estimates of ET. This study introduces a practical approach that overcomes (in part) the previous limitations by implementing machine learning techniques that are accurate and robust. The analysis was applied to the Canal B service area of the Delta Canal Company in central Utah using data from the 2009-2011 growing seasons. Actual ET was calculated by an algorithm using data from satellite images. A relevance vector machine (RVM), which is a sparse Bayesian regression, was used to build a spatial model for ET. The RVM was trained with a set of inputs consisting of vegetation indexes, crops, and weather data. ET estimated via the algorithm was used as an output. The developed RVM model provided an accurate estimation of spatial ET based on a Nash-Sutcliffe coefficient (E) of 0.84 and a root-mean-squared error (RMSE) of 0.5 mmday-1. This methodology lays the groundwork for estimating ET at a spatial scale for the days when a satellite image is not available. It could also be used to forecast daily spatial ET if the vegetation indexes model inputs are extrapolated in time and the reference ET is forecasted accurately.

  8. Spatiotemporal Variability in Potential Evapotranspiration across an Urban Monitoring Network

    NASA Astrophysics Data System (ADS)

    Miller, G. R.; Long, M. R.; Fipps, G.; Swanson, C.; Traore, S.

    2015-12-01

    Evapotranspiration in urban and peri-urban environments is difficult to measure and predict. Barriers to accurate assessment include: the wide range of microclimates caused by urban canyons, heat islands, and park cooling; limited instrument fetch; and the patchwork of native soils, engineered soils, and hardscape. These issues combine to make an accurate assessment of the urban water balance difficult, as evapotranspiration calculations require accurate meteorological data. This study examines nearly three years of data collected by a network of 18 weather stations in Dallas, Texas, designed to measure potential evapotranspiration (ETo) in support of the WaterMyYard conservation program (http://WaterMyYard.org). Variability amongst stations peaked during the summer irrigation months, with a maximum standard deviation of 0.3 mm/hr and 4 mm/d. However, we found a significant degree of information overlap in the network. Most stations had a high correlation (>0.75) with at least one other station in the network, and many had a high correlation with at least 10 others. Correlation strength between station ETo measurements did not necessarily decrease with Euclidean distance, as expected, but was more closely related to differences in station elevation and longitude. Stations that had low correlations with others in the network typically had siting and fetch issues. ETo showed a strong temporal persistence; average station autocorrelation was 0.79 at a 1-hour lag and 0.70 at a 24-hour lag. To supplement the larger-scale network data, we deployed a mobile, vehicle-mounted weather station to quantify deviations present in the atmospheric drivers of evapotranspiration: temperature, humidity, wind, and solar radiation. Data were collected at mid-day during the irrigation season. We found differences in mobile and station ETo predictions up to 0.2 mm/hr, primarily driven by wind speed variations. These results suggest that ETo variation at the neighborhood to municipality

  9. Using Landsat data to estimate evapotranspiration of winter wheat

    NASA Technical Reports Server (NTRS)

    Kanemasu, E. T.; Heilman, J. L.; Bagley, J. O.; Powers, W. L.

    1977-01-01

    Results obtained from an evapotranspiration model as applied to Kansas winter wheatfields were compared with results determined by a weighing lysimeter, and the standard deviation was found to be less than 0.5 mm/day (however, the 95% confidence interval was between plus and minus 0.2 mm/day). Model inputs are solar radiation, temperature, precipitation, and leaf area index; an equation was developed to estimate the leaf area index from Landsat data. The model provides estimates of transpiration, evaporation, and soil moisture.

  10. Evaluation of different interpolation schemes for precipitation and reference evapotranspiration and the impact on simulated large-scale water balance in Slovenia

    NASA Astrophysics Data System (ADS)

    He, Qianwen; Molkenthin, Frank; Wendland, Frank; Herrmann, Frank

    2016-04-01

    Precipitation and reference evapotranspiration (ET0) are two main climate input components for hydrological models, which are often recorded or calculated based on measuring stations. Interpolation schemes are implemented to regionalize data from measuring stations for distributed hydrological models. This study had been conducted for 5 months, with the aim of: (1) evaluating three interpolation schemes for precipitation and reference evapotranspiration (ET0); (2) assessing the impact of the interpolation schemes on actual evapotranspiration and total runoff simulated by a distributed large-scale water balance model - mGROWA. The study case was the Republic of Slovenia, including a high variability in topography and climatic conditions, with daily meteorological data measured in 20 stations for a period of 44 years. ET0 were computed by both FAO Penman-Monteith equation and Hargreaves equation. The former equation is recommended as the standard equation, while the ET0 calculated by the latter one for Slovenia had a certain deviation (+150 mm/a) from it. Ordinary Kriging, Regression Kriging and Linear Regression were selected to regionalize precipitation and ET0. Reliability of the three interpolation schemes had been assessed based on the residual obtained from cross-validation. Monthly regionalized precipitation and ET0 were subsequently used as climate input for mGROWA model simulation. Evaluation of the interpolation schemes showed that the application of Regression Kriging and Linear Regression led to an acceptable interpolation result for reference evapotranspiration, especially in case the FAO Penman-Monteith equation was used. On the other hand, Regression Kriging also provided a more convincing interpolated result for precipitation. Meanwhile, mGROWA simulation results were affected by climate input data sets generated by applying difference interpolation schemes. Therefore, it is essential to select an appropriate interpolation scheme, in order to generate

  11. Stereospecific alkylations of molybdenum(II) enolates from eta/sup 2/-aceyl complexes

    SciTech Connect

    Rusik, C.A.; Templeton, J.L.

    1986-07-23

    The authors report here spectroscopic characterization and alkylation and aldol reactions of these Mo(II) enolate complexes as well as the structure of one diastereomer of (Tp')Mo(CO)(P(OPh)/sub 3/)(C(O)CHMEBz), Tp' = hydridotris(3,5-dimethylpyrazolyl)borate). Aldol condensation reactions of transition-metal enolates have not been reported as frequently as alkylation reactions. The authors find that metal enolate reacts with benzaldehyde to yield a deep indigo eta/sup 2/-enone derivative resulting from dehydration of the initial ..beta..-hydroxy eta/sup 2/-acyl product. The formation of (Tp')CO)/sub 2/Mo(eta/sup 2/-C(O)CMe = CHPh) (9) suggests that a range of electrophiles will react with these molybdenum(II) enolate reagents.

  12. Evidence for the decay tau/sup -/. -->. pi. /sup -/eta nu/sub tau/

    SciTech Connect

    Repond, J.

    1987-01-01

    The inclusive production of eta mesons in tau lepton decay has been studied using the High Resolution Spectrometer at the PEP e/sup +/e/sup -/ facility. The data sample corresponds to an integrated luminosity of 300 pb/sup -1/ and the storage ring was operated at ..sqrt..s = 29 GeV. The eta production appears to be only compatible with the decay tau/sup -/ ..-->.. ..pi../sup -/eta nu, which violates isospin and G-parity conservation. The branching ratio of 5.1 +- 1.5% explains much of the current discrepancy between the one-prong topological branching ratio and the sum of the individual one-prong modes. Various checks to test the validity of the signal are described.

  13. Brighter Still! A Summary of Photometric Data from the HST Eta Carinae Treasury Project

    NASA Astrophysics Data System (ADS)

    Martin, John C.; Davidson, K.; Koppelman, M. D.; Humphreys, R. M.

    2006-12-01

    During the past decade Eta Carinae has brightened markedly, indicating a possible change of state. Here we summarize the photometry of just the central star including STIS/CCD and ACS/HRC data gathered for the HST Eta Carinae Treasury project. The current eight-year brightening trend is reminiscent of 1938--1953 when the 5.5 year spectroscopic cycle first appeared. Already the brightness of the central star has begun to overwhelm the bright inner ejecta. Our results indicate that its mass loss rate is probably decreasing. Over the coming decades this should cause the ionization of the Little Homunculus and other envelopes of ejecta, dramatically altering the appearance of Eta Car.

  14. Circumventing the eta problem in building an inflationary model in string theory

    SciTech Connect

    Easson, Damien A.; Gregory, Ruth

    2009-10-15

    The eta problem is one of the most significant obstacles to building a successful inflationary model in string theory. Planck mass suppressed corrections to the inflaton potential generally lead to inflaton masses of order the Hubble scale and generate contributions of order unity to the {eta} slow-roll parameter rendering prolonged slow-roll inflation impossible. We demonstrate the severity of this problem in the context of brane antibrane inflation in a warped throat of a Calabi-Yau flux compactification with all phenomenologically dangerous moduli stabilized. Using numerical solutions we show that the eta problem can be avoided in scenarios where the inflaton is nonminimally coupled to gravity and has Dirac-Born-Infeld kinetic term. We show that the resulting cosmic microwave background observables such as measures of non-Gaussianites can, in principle, serve as a probe of scalar-gravity couplings.

  15. The Spatially-resolved Interacting Winds of Eta Carinae: Implications on the Orbit Orientation

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Nielsen, K.E.; Corcoran, M.; Hamaguchi, K.; Madura, T.; Russell, C.; Hillier, D.J.; Owocki. S.; Okazaki, A.T.

    2010-01-01

    Medium-dispersion long slit spectra, recorded by HST/STIS (R=8000, Theta=0.l"), resolve the extended wind-wind interaction region of the massive binary, Eta Carinae. During the high state, extending for about five years of the 5.54-year binary period, lines of [N II], [Fe III], [S III], [Ar III] and [Ne III] extend outwards to 0.4" with a velocity range of -500 to +200 km/s. By comparison, lines of [Fe II] and [Ni II] extend to 0.7" with a velocity range of -500 to +500 km/s. During the high state, driven by the lesser wind of Eta Car B and photo-ionized by the FUV of Eta Car B, the high excitation lines originate in or near the outer ballistic portions of the wind-wind interaction region. The lower excitation lines ([Fe II] and [Ni II D originate from the boundary regions of the dominating wind of Eta Car A. As the binary system has an eccentricity exceeding 0.9, the two stars approach quite close across the periastron, estimated to be within 1 to 2 AU. As a result, Eta Car B moves into the primary wind structure, cutting off the FUV supporting the ionization of the high state lines. Forbidden emission lines of the doubly-ionized species disappear, He II 4686 drops along with the collapse of the X-ray flux. This behavior is understood through the 3-D models of A. Okazaki and of E. R. Parkin and Pittard. Discussion will address the orbit orientation relative to the geometry of the Homunculus, ejected by Eta Carinae in the 1840s.

  16. NUV Spectroscopic Studies of Eta Car's Weigelt D across the 2003.5 Minimum

    NASA Technical Reports Server (NTRS)

    Ivarsson, S.; Nielsen, K. E.; Gull, T. R.; Hillier, J. D.

    2006-01-01

    HST/STIS high dispersion, high spatial resolution spectra in the near UV (2424-2705A) were recorded of Weigelt D, located 0.25" from Eta Carinae, before, during and after the star's 2003.5 minimum. Most nebular emission, including Lyman-alpha pumped Fe II and [Fe III] lines show phase dependent variations with disappearance at the minimum and reappearance a few months later. Circumstellar absorptions increase at minimum, especially in the Fe II resonance lines originating not only from ground levels but also meta stable levels well above the ground levels. These ionization/excitation effects can be explained by a sudden change in UV flux reaching the blobs, likely due to a line-of-sight obscuration of the hotter companion star, Eta Car B, recently discovered by Iping et al. (poster, this meeting). The scattered starlight seen towards Weigelt D display noticeable different line profiles than the direct starlight from Eta Carinae. P-Cygni absorption profiles in Fe II stellar lines observed directly towards Eta Carinae, show terminal velocities up to -550 km/s. However, scattered starlight of Weigelt D display significant lower velocities ranging from -40 to -150 km/s.We interpret this result to be indicative that no absorbing Fe II wind structure exists between the Central source and Weigelt D. The lower velocity absorption appears to be connected to the outer Fe II wind structure of Eta Car A extending beyond Weigelt D intersecting the observer's line of sight. This result is consistent with the highly extended wind of Eta Car A.

  17. Distinct ETA receptor binding mode of macitentan as determined by site directed mutagenesis.

    PubMed

    Gatfield, John; Mueller Grandjean, Celia; Bur, Daniel; Bolli, Martin H; Nayler, Oliver

    2014-01-01

    The competitive endothelin receptor antagonists (ERA) bosentan and ambrisentan, which have long been approved for the treatment of pulmonary arterial hypertension, are characterized by very short (1 min) occupancy half-lives at the ET(A) receptor. The novel ERA macitentan, displays a 20-fold increased receptor occupancy half-life, causing insurmountable antagonism of ET-1-induced signaling in pulmonary arterial smooth muscle cells. We show here that the slow ET(A) receptor dissociation rate of macitentan was shared with a set of structural analogs, whereas compounds structurally related to bosentan displayed fast dissociation kinetics. NMR analysis showed that macitentan adopts a compact structure in aqueous solution and molecular modeling suggests that this conformation tightly fits into a well-defined ET(A) receptor binding pocket. In contrast the structurally different and negatively charged bosentan-type molecules only partially filled this pocket and expanded into an extended endothelin binding site. To further investigate these different ET(A) receptor-antagonist interaction modes, we performed functional studies using ET(A) receptor variants harboring amino acid point mutations in the presumed ERA interaction site. Three ET(A) receptor residues significantly and differentially affected ERA activity: Mutation R326Q did not affect the antagonist activity of macitentan, however the potencies of bosentan and ambrisentan were significantly reduced; mutation L322A rendered macitentan less potent, whereas bosentan and ambrisentan were unaffected; mutation I355A significantly reduced bosentan potency, but not ambrisentan and macitentan potencies. This suggests that--in contrast to bosentan and ambrisentan--macitentan-ET(A) receptor binding is not dependent on strong charge-charge interactions, but depends predominantly on hydrophobi