Extended Abstract (1.2M)1.2
Estimation of potential evapotranspiration from merged CERES and MODIS observations
Anand K. Inamdar, USDA/ARS, Maricopa, AZ; and A. French
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 inconsistency of ground-based measurements of potential ET , satellite remote sensing offers the best hope of providing such data. In the present study, we explore a new methodology to estimate potential ET by taking advantage of the new generation of the Earth Observation System (EOS) satellites. While there have been many studies on satellite-based estimation of ET, they are limited to clear-sky conditions and for a fixed overpass time. The approach outlined here utilizes the Clouds and the Earth's Radiant Energy System (CERES) instrument as a calibration source for the Moderate Resolution Imaging Spectroradiometer (MODIS) imager to produce estimates of net radiation at the surface at the spatial scale of 1 km, which is input into an appropriate surface energy balance formulation. The objective is to take advantage of the extensively developed and well validated CERES top-of-atmosphere (TOA) to surface flux algorithms and extend the same to MODIS by implementing a suitable narrowband-to-broadband conversion scheme for the MODIS imager channels. The diurnal variations of potential ET are further modeled by employing the visible channel data from the geostationary environmental satellite (GOES 10). The potential ET estimates will be compared with measurements at several North American sites with varying land cover types.
Session 1, Hydrology and Water Resources
Monday, 12 January 2009, 10:45 AM-12:00 PM, Room 127BC
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