Evaluation of TRMM rainfall products for hydrological uses at different scales

Abstract

The principal objectives of the thesis are two: firstly to study the accuracy of the satellite rainfall products in climatologically distinctive places at different scales and secondly to find the possibility of using satellite-rain gauge blended rainfall products for hydrological purposes. Three case study areas Catalunya, Bangladesh, and South Africa have been chosen for the analysis using the satellite rainfall products (TMPA) and rain gauge records for the period from January 2005 to December 2009. The areal pattern of rainfall has been presented using satellite rainfall products over the case study areas. Both daily and monthly products are showing good agreement with rain gauge records although it is highly variable with space and seasonality. From the results, it can be shown that TRMM satellite identified the seasonal variability of rainfall. Moreover, the mean TRMM rainfall products show same pattern as like mean rain gauge observations in daily and monthly scale in all case study areas.Finally, a blending technique is applied (originally used for radar-rain gauge blending) to conform satellite rainfall products to rain gauge observations. This blended product is also tested against the rain gauge records to verify the improvement of the blended rainfall products over the original satellite products. Results of blended rainfall products enlightens few aspects or issues that should consider before applying blending technique including density of rain gauge network and resolution of TRMM pixel.