Author(s): Biswa Bhattacharya, Md. Tohidul Islam, Md. Sohel Masud, Surafel Mamo, Mjawa Shenduli, Prabin Rokaya, Schalk Jan Van Andel, Ilyas Masih
Linked Author(s): Biswa Bhattacharya
Keywords: Rainfall, TRMM, Brahmaputra, Upper Awash, Kaap
Abstract: The lack of hydro-meteorological data for a large number of catchments around the world is a major constraint to implementing efficient water resources management. One of the possible solutions to the scarcity of rainfall data or transboundary data issues seems to be in making use of the variety of satellite based estimates and meteorological model products for rainfall. The abundance of a variety of rainfall products such as TRMM, WATCH, ERA-Interim, etc. provide a good basis of hydrological modeling in data-scarce catchments. The usefulness of the satellite based rainfall data needs further validation with hydrological modeling, by comparing simulated hydrodynamic/hydrological response with the measured ones. In this respect, the spatio-temporal scale is an important aspect to reckon as refining the temporal/ spatial scale may increase uncertainty due to the inherent incompatibility between the different spatio-temporal scales of different meteorological products and hydrological simulation. The following three catchments ware chosen for the research: Brahmaputra (India), Upper Awash (Ethiopia) and Kaap (Swaziland, South Africa). Rainfall estimates from TRMM and atmospheric models (ECMWF) are compared with gauge rainfall at different spatial and temporal scales. The comparison shows that the satellite based rainfall products are comparable to gauge rainfall at fortnightly or monthly temporal scales. The accuracy drops for shorter temporal scales (~weekly) but for the daily scale the error level is substantial. The spatial scale also plays an important role. With larger spatial scales the accuracy increases. Lumped conceptual hydrological models are built for the three catchments. Hydrological simulation of the catchments using gauge and satellite based rainfall estimates shows promising results. It is concluded that the satellite based rainfall estimates, together with the gauge rainfall, can be used in the optimal use of the catchments
Year: 2017