Changes in Evapotranspiration due to Anthropogenic Changes in Land Cover in Monsoon Asia

Abstract

The changes in areal potential evaporation over Monsoon Asia due to land cover changes are estimated by using several global datasets in Global Ecosystem Database version 1.0 CD-ROM (GEDB) by NOAA/EPA.
Cluster analysis is applied to monthly NDVIs in 1990 over Monsoon Asia (60°N-20°S, 60°E-160°E) . Forty-eight classes are obtained based on the phenology of the vegetation, and land cover type of each class is determined by warmth index, precipitation and by geographic locations.
Characteristic values of air temperature, cloudiness and seasonal albedos of each class are extracted from GEDB, and areal potential evaporation for current vegetation is calculated using the method of Ahn and Tateishi (1994) based on Priestley and Taylor method.
Natural vegetation of the area of which current land cover is grassland or cropland, is restored by referring Leeman's Holdridge Life Zone dataset. The eastern and southern parts of China and India are subjected to extensive land cover change. Central plains of Myanmar and Thailand are also experienced large land cover change. Areal potential evaporation is calculated for natural vegetation.