CHARACTERIZING SPATIAL AND TEMPORAL VARIATIONS OF SURFACE TEMPERATURE OF LAKE TANA (ETHIOPIA) USING MODIS DATA

The information of water surface temperature (WST) is essential for many applications such as the estimation of evaporation from lakes and reservoirs. Generally, there is rarely continuous long-term in-situ measurement of water surface temperature for most lakes especially in developing countries. The freely available satellite data is an alternative or even the only data source for obtaining WST over a given lake. This study characterized the spatial and temporal variations of WST over Lake Tana (Ethiopia) using the Version 5 Terra Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature product, namely, MOD11_L2. The MOD11_L2 data during the year 2006 were selected. Twelve maps of monthly mean WST over Lake Tana were generated. The lake-wide mean WST (L-WST) were further computed by averaging all pixels of WST to construct the time-series of monthly L-WST. The spatial variations of monthly WST value can range from 1.73 degrees C in November to 5.42 degrees C in July. The L-WST ranges from 21.27 degrees C in December to 24.86 degrees C in May.