Satellite Remote Sensing of Surface water evaporation over Lake Mutirikwi, Zimbabwe

Abstract

Evaporation from large water bodies is an important hydrological parameter as it dominates water balance in arid and semi-arid climates. Small changes in actual evaporation can lead to large changes in surface water flows, but its estimation on large water surfaces has continued to be elusive because it is typically calculated as the residual loss from storage. Improved measurement of evaporation from storages would increase confidence in available resources for allocation planning and improve the accuracy of water accounting. In this study, a Surface Energy Balance System (SEBS) using Terra MODIS satellite earth observation data in combination with meteorological information was successfully used for the estimation of spatial evaporative over Lake Mutirikwi in Zimbabwe. Results showed that there is no significant difference (Independent samples t-test, p =0.078, df = 18 and p=0.581) in the mean evaporation estimates of SEBS and Pan method for June and September 2009. Based on these cases, SEBS has proven to be capable to estimate spatial evaporation in large water bodies at various scales. In conclusion surface energy balance using satellite images is suitable for estimating loss through evaporation in large water bodies, particularly where measurements are not available.