Evaluation of the performance of gridded precipitation products over Balochistan Province, Pakistan

Gauge-based gridded precipitation estimates are emerged as a supplementary source of precipitation data where in-situ precipitation data are not readily available. In this study, four widely used gauge-based gridded precipitation products, namely Global Precipitation Climatology Centre (GPCC), Climatic Research Unit (CRU), Asian Precipitation Highly Resolved Observational Data Integration towards Evaluation (APHRODITE), and Center for Climatic Research-University of Delaware (UDel) are compared with in-situ precipitation at three stations located in semi-arid, arid, and hyper-arid regions of Balochistan province, Pakistan. The assessment is carried out at monthly scale and at 0.5 degrees resolutions during 1961-2007. The performance of the data products is evaluated using various statistical approaches including root mean square error (RMSE), bias, non-parametric Kendall rank correlation, and the Mann-Kendall's trend test. The results reveal that the performance of different products varies at different stations. However, GPCC is found considerably better than other products showing high agreement with annual and seasonal precipitation. GPCC also showed lower errors and higher correlations than other products. Albeit with the lack of spatially dense precipitation data in the study domain, this study suggests GPCC precipitation estimates as the most suitable product for the climatic and hydrological studies in a predominantly arid region like Balochistan.