Abstract
Use of the satellite and reanalysis precipitation products, as supplementary data sources, are steadily rising for hydrometeorological applications, especially in data-sparse areas. However, the accuracy of these data sets is often lacking, especially in Turkey. This study evaluates the accuracy of satellite precipitation product (TRMM 3B42V7) and reanalysis precipitation product (NCEP-CFSR) against rain gauge observations for the 1998–2010 periods. Average annual precipitation for the 25 basins in Turkey was calculated using rain gauge precipitation data from 225 stations. The inverse distance weighting (IDW) method was used to calculate areal precipitation for each basin using GIS. According to the results of statistical analysis, the coefficient of determination for the TRMM product gave satisfactory results (R2 > 0.88). However, R2 for the CFSR data set ranges from 0.35 for the Eastern Black Sea basin to 0.93 for the West Mediterranean basin. RMSE was calculated to be 95.679 mm and 128.097 mm for the TRMM and CFSR data, respectively. The NSE results of TRMM data showed very good performance for 6 basins, while the PBias value showed very good performance for 7 basins. The NSE results of CFSR data showed very good performance for 3 basins, while the PBias value showed very good performance for 6 basins.
Highlights
E coefficient of determination (R2) was observed to be generally above 0.90. is shows that tropical rainfall measuring mission (TRMM) data are in a high linear relationship with the data measured from the precipitation observation station. e average root-mean-square error (RMSE) value of the basins for the total annual precipitation amount was calculated as 95.679 mm. e highest RMSE value was calculated for the Coruh Basin (215.11 mm), and the lowest
Percent bias (PBias) values were found positive 4.59% and 2.73% for the Asi and Eastern Black Sea basins, respectively. ese positive values are indicating that the areal precipitation for these basins was underestimated by TRMM
According to PBias values, estimation abilities were found very good for Susurluk, Antalya, Burdur Lakes, Akarcay Ceyhan, and Lake Van basins. ese low-magnitude values are indicating that Climate Forecast System Reanalysis (CFSR) data are more accurate for these basins
Summary
Observations have been done by the General Directorate of Meteorology (DMI) in Turkey using rain gauges. E ground base data from the observation stations belonging to DMI within the basins were obtained from the previous study done by Kayhan and Alan [19]. TRMM 3B42V7 monthly precipitation data covering the years 1998–2018 for Turkey have been downloaded from https://mirador.gsfc. E CFSR (Climate Forecast System Reanalysis), the coupled atmosphere-ocean-land system, is developed at NOAA-NCEP and provides meteorological parameters including precipitation, temperature, wind speed, relative humidity, and radiation, available from 1979 to present [21,22,23]. CFSR precipitation data for Turkey (1979–2010) were obtained from https://rda. CFSR precipitation data for Turkey (1979–2010) were obtained from https://rda. ucar.edu/ as a file with an extended csv. format
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