Kajian Koefisien Koreksi Indeks Kekeringan Menggunakan Basis Data Satelit TRMM Dan Hujan Lapangan

. Analyzing drought requires a long period of rainfall data more than 30 years. Obtaining enough rainfall data, however, it is very difficult especially for areas outside of Java that have limited data. To solve this problem, the possibility of using Tropical Rainfall Measuring Mission (TRMM) satellite rainfall data to substitute long-period of rainfall data is examined. For a case study, data from Pemali Comal river basin is used. This study is aimed to obtain the value of drought correction coefficient index based on the TRMM data, so that the data can be used as an alternative to analyze drought index / severity of drought in areas with limited rainfall data. Standardized Precipitation Index (SPI) method is used to analyze drought severity, and the correction factor is determined by Root Mean Square Error (RMSE) with 0.5 as a threshold. Then the RMSE is compared between RMSE SPI of long period of groundstation rainfall data (1951-2013) and the TRMM satellite data (2002-2013). The results is that the average RMSE SPI correction is <0.5 for all SPI time scales, while the average RMSE without correction, correction α-β (whole region and sub-region) were > 0.5. Thus, the TRMM data with SPI correction can be used in the analysis of the SPI drought at all the time scale