An application of thermal inertia in regional evapotranspiration retrieval

Abstract:

Accurate estimates of the spatial distribution of evapotranspiration (ET) are of crucial importance in disciplines of hydrology, meteorology and agriculture, especially in arid and semi-arid areas where water scarcity is becoming a major constraint on economic welfare and sustainable development. Space feature models are widely used in estimating ET nowadays. The locations of dry line and wet line are important to the retrieving results, especially for the dry lines, which are more difficult to determine than wet lines since dry lines do not exist in wet period. In this paper, simplified thermal inertia values of sandy soil samples and full vegetation covered samples measured in laboratory are used in the middle reaches of Heihe River to determine the locations of dry line in wet periods and dry periods. Six Aster images form 1^st June to 12^th September of Year 2012 are used in the study. The results shows that the ET results from our approach shows a high agreement (R > 0.85) with the observed ET in Heihe and the method can be used in Heihe area to estimate regional ET.