Evaluation of the Hydro-Estimator Algorithm over Saudi Arabia on a Seasonal Scale

In applications of meteorology and hydrology, the availability of good-quality precipitation estimates at regional and global scales is very important. For acceptable data representation, frequent and closely spaced observations are required due to high variability of precipitation data in spatial and temporal domain. Consequently, satellite-based precipitation products have been used in many research fields. The aim of this study is to evaluate the satellite-based precipitation data Hydro-Estimator (HE) product in seasonal scale over the Saudi Arabian region that has arid-climate conditions. In this study, 30 rainfall observation stations were used and monthly total rainfall data obtained from these stations were evaluated with the HE product in seasonal scale. In the evaluation, amount of rainfall and topography were compared with rainfall regimes. According to results, significant relationship between these two datasets was not determined in monthly based evaluations. However, generalized relation between the HE product and the gauge data was obtained in seasonal-based evaluations. To measure the relation between two data, the coefficient of determination (r2) was used as a guideline. Based on the results, the HE product underestimated the rainfall amounts in wet season whereas, overestimated the rainfall amounts in dry and transitional seasons. Moreover, the best result (r2=0.86) was observed in dry season. Generally, both datasets gave high rainfall amounts in topographically high regions. However, it was also observed that the height was not the only factor in the distribution of rainfall