HR: 12:05h
AN: H32A-08    [Abstracts]
TI: An algorithm for estimation of evapotranspiration for all sky conditions
AU: * Jutla, A S
EM: antarpreet.jutla@tufts.edu
AF: Tufts University, 200 College Ave, 113 Anderson Hall, Medford, MA 02155, United States
AU: Islam, S
EM: shafiqul.islam@tufts.edu
AF: Tufts University, 200 College Ave, 113 Anderson Hall, Medford, MA 02155, United States
AB: An algorithm is developed for estimation of actual evapotranspiration (ET) for all sky conditions using primarily remote sensing data. Our approach is based on an extension of the Priestley-Taylor equation, a contextual interpretation of remotely sensed surface temperature and vegetation index, and estimation of net radiation from remotely sensed data. For cloud free days, net radiation is computed using MODIS-Terra data and a simple sinusoidal model to obtain the diurnal variation of radiation. If a particular day is cloudy for a MODIS-Terra pixel, we use data from MODIS-Aqua which has a different orbital pass time. If a pixel is cloudy for Terra and Aqua overpass times, then a set of regression relationships are used to estimate net radiation and surface temperature. For cloudy days, the algorithm first computes the shortwave radiation using a regression model between clear sky shortwave radiation and cloud fraction. Then, net radiation is computed using a linear regression model between estimated shortwave radiation for cloudy days. Surface temperature is estimated using regression model between calculated net radiation and cloud cover. Once the surface temperature is estimated, a contextual interpretation of surface temperature and vegetation index is used to obtain ET. Results from calibration and validation of the proposed ET estimation algorithm for all sky conditions over the Southern Great Plains will be presented.
DE: 1814 Energy budgets
DE: 1816 Estimation and forecasting
DE: 1818 Evapotranspiration
DE: 1855 Remote sensing (1640)
DE: 3315 Data assimilation
SC: Hydrology [H]
MN: 2007 Joint Assembly