Comparison of rainfall estimations by TRMM 3B42, MPEG and CFSR with ground-observed data for the Lake Tana basin in Ethiopia

Abstract

Abstract. Planning for drought relief and floods in developing countries is greatly hampered by the lack of a sufficiently dense network of weather stations measuring precipitation. In this paper, we test the utility of three satellite products to augment the ground-based precipitation measurement to provide improved spatial estimates of rainfall. The three products are the Tropical Rainfall Measuring Mission (TRMM) product (3B42), Multi-Sensor Precipitation Estimate-Geostationary (MPEG) and the Climate Forecast System Reanalysis (CFSR). The accuracy of the three products is tested in the Lake Tana basin in Ethiopia, where 38 weather stations were available in 2010 with a full record of daily precipitation amounts. Daily gridded satellite-based rainfall estimates were compared to (1) pointobserved ground rainfall and (2) areal rainfall in the major river sub-basins of Lake Tana. The result shows that the MPEG and CFSR satellites provided the most accurate rainfall estimates. On average, for 38 stations, 78 and 86 % of the observed rainfall variation is explained by MPEG and CFSR data, respectively, while TRMM explained only 17 % of the variation. Similarly, the areal comparison indicated a better performance for both MPEG and CFSR data in capturing the pattern and amount of rainfall. MPEG and CFSR also have a lower root mean square error (RMSE) compared to the TRMM 3B42 satellite rainfall. The bias indicated that TRMM 3B42 was, on average, unbiased, whereas MPEG consistently underestimated the observed rainfall. CFSR often produced large overestimates.

Using gridded rainfall products in simulating streamflow in a tropical catchment – A case study of the Srepok River Catchment, Vietnam

“…The results of these studies indicate that the quality of gridded rainfall datasets varies with different topography and regions (Lauri et al, 2014;Worqlul et al, 2014). For example, TRMM products show their best match to rain gauges data over the Nzoia River Basin in Kenya (Ouma et al, 2012), over the Mekong River Basin (Lauri et al, 2014), and over Malaysia (Tan et al, 2015).…”

Comparison and validation of eight satellite rainfall products over the rugged topography of Tekeze-Atbara Basin at different spatial and temporal scales

“…In most regions, rainfall increases with elevation due to the orographic uplifts (Moreno et al, 18 2014;worqlul et al, 2014). However, this relationship is not uniform in the T-A Basin ( Fig.2b).…”

“…Several studies on the validation and comparisons of these products with ground measurements have been conducted at different scales (e.g. Dinku et al, 2007;Feidas, 2010;Guo & Liu, 2016;Hessels, 2015;Hu et al, 2014;Jiang et al, 2012;Thiemig et al, 2012;Worqlul et al, 2014).…”

“…Validation and inter-comparison of different rainfall products over the complex topography of satellite rainfall products (e.g., Dinku et al, 2007;Gebremichael et al, 2014;Haile et al, 2013;Worqlul et al, 2014;Beyissa et al, 2017 The basin is characterized by a semi-arid climate in the east and north and partly semi-humid in the south (Belete, 2007). More than 85 % of the total annual rainfall falls in the wet season 4 (June -September) which varies from 400 mm yr -1 in the east to more than 1200 mm yr -1 in the south (Fig.…”

Comparing CFSR and conventional weather data for discharge and soil loss modelling with SWAT in small catchments in the Ethiopian Highlands

“…Fuka et al (2014) used CFSR data in a 1200 km 2 watershed in Ethiopia with SWAT suggesting CFSR data perform as well or even better than conventional precipitation. Worqlul et al (2014) correlated conventionally recorded rainfall with CFSR data over the Lake Tana basin (15 000 km 2 ). They suggested that seasonal patterns could adequately be captured although the CFSR data did uniformly overestimate and underestimate measured rainfall.…”