Evaluation of Satellite-based Precipitation Estimates (3B43) and Comparison with Kriging Interpolation Results

It is important to achieve accurate monthly precipitation field for climatology and evaluation simulated result of regional models. Because of high temporal and spatial precipitation variability، as well as limited rain gauges، improvements in precipitation estimates using satellite images is critical. Some projects have initiated in this purpose and many products have been produced. Monthly 3B43 product of TRMM project is one of them that have been evaluated in this paper. Precision of monthly and annually 3B43 product have been evaluated during 2001-2003 using Weather Organization synoptic and climatology station data. Result showed that usually values less than average have been overestimated and values more than average have been underestimated. Also precision of values less than average is lower. Nevertheless there has seen no correlation between precision of this product with thermal and humidity characteristics of mounts. Besides، precision amount is various in different zones of Iran، so that in South of Alborz mountain range، central and somewhat Eastern regions of Iran it is incredible; while in Western and Southern regions it is credible. Because precision of 3B43 product is lower than precision of Kriging interpolation technique estimates، thus utilize of this product is not recommended.