Evapotranspiration (ET) is a major part of the water cycle. Reliable measurements or estimates of ET can greatly improve quantitative forecasts and hindcasts of water demand by crops, horticulture, and natural vegetation, and also help to manage and conserve water resources. Direct measurement of ET requires not only specific devices such as eddy covariance instruments, but also well-trained research personnel to collect accurate data. As a result, a variety of indirect methods for estimating ET have been developed in recent decades.
DGS is collaborating with climate scientist Kevin Brinson (DEOS) and Tracy DeLiberty (Dept. of Geography) to develop and test methods to estimate and map annual and seasonal distribution of evapotranspiration (ET) for Sussex County, Delaware. Remotely sensed data from Landsat 7 ETM+ and MODIS platforms will be used to estimate regional energy balance and water flux. These estimates are calibrated by comparison to ET estimates determined by direct point measurements (Eddy Covariance and atmometer) and models driven by meteorological data such as temperature, relative humidity, wind speed, and soil moisture. The results have the potential to improve accuracy and precision of ET models and will be valuable for efforts that use water budgets for resource management, agriculture, wetland assessment, and research.
A final report was submitted for publication as a DGS Report of Investigations in January 2019.