THE IMPORTANT OF GLOBAL PRECIPITATION MEASUREMENT IN UNGAUGED CATCHMENT

In line with the technological development in the remote sensing field like satellite data, the measurement of rainfall can be carried out by rainfall monitoring in large areas even in places that cannot be reached by conventional tools. This superiority can be utilized to get the rainfall in a region for the importance of water resources management due to the validity and accuracy that can be reliable and represent the rainfall characteristic. Research about the utilization of Global Precipitation Measurement (GPM) data is conducted in the Wonogiri ungauged catchment. However, to utilize the satellite rainfall data is necessary to be carried out a correction, so the rainfall characteristic that is produced by the satellite is close to the condition of observed rainfall data. The correcting is carried out by multiplying every data interval with a certain coefficient, so the produced value by the satellite data approaches the value characteristic that is produced by observed rainfall. Based on the result of trial and error, there is produced as follows: for the interval between 0 and 2 mm, the correction coefficient is 0; for the interval between 2 and 20 mm, the correction coefficient is 0.075; for the interval between 20 until 30 mm, the correction coefficient is 0.8; for the interval between 30 until 50 mm, the correction coefficient is 0.85; and for the interval more than 50 mm, the correction coefficient is 0.95.