Satellite Precipitation Estimates (SPEs) and Their Validation Using Ground-Based Measurments: A Case Study in Uttarakhand State, India

摘要

Hilly regions are characterized by high spatio-temporal variations in climatic characteristic such as rainfall due to variations in the topography. Uttarakhand State is very susceptible to flooding and cloudburst occasions like one happened at Kedarnath area in June 2013. Estimation of rainfall over a hilly region is a challenging task due to scarcity of rain gauge network. Due to the existing gaps and uncertainty in the rainfall data, these regions are susceptible to disasters such as cloudburst and flash floods. Proper understanding of the precipitation patterns of these regions is required so that disaster mitigation plans can be made and implemented accordingly. Remotely sensed and improved, high-resolution rainfall data derived from Tropical Rainfall Measuring Mission (TRMM) satellite can be used as an alternative to the rain gauge observed rainfall data. However, a proper validation of the satellite-derived products is necessary before using it for various applications. This study aims to compare monthly and monsoon seasons precipitation derived product from Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) with the observed rain gauge analysis from January 1998 to December 2012. Statistical investigation was done for computing relationship of the TMPA product with the rain gauge station data. Statistical indices showing good agreements with the rain gauge data on monthly as well as monsoon seasons time scales. It was observed that the TRMM 3B43 rainfall estimates were much closer to the rain gauge data, with minimal biases. It is suggested to develop satellite precipitation retrieval algorithms by combining the topographical and local climatic factors into consideration.