Application satellite prepitation data to calculate SPI for ungage area – apply for Sedone basin, Laos

Abstract

    The Sedone basin on Lao PDR have few meteorological stations and uneven distribution. The curent rainfall data are mostly measured at hydrology stations which are unvevenly distributed in Sedone basin. This research calculates Standardized Precipitation Index (SPI) from CHIRPS (Climate Hazards Group Infrared Precipitation with Stations) with hight resolution (~5.5 km) conbined with monthly rainfall recorded from 1990 to now at The Hydrology station in the basin .
The results show that the precipitation from CHIRPS and observed rainfall have correlation coefficient > 0.7. The SPI calculated with precipitation from CHIRPS and observed rainfall at eight observed stations on Sedone basin show that the correlation coefficient > 0.7 (for SPI 3, SPI 9), correlation coefficient > 0.8 for SPI 6. The CHIRPS data from 1981 to now used to simulate SPI for ungagged area on Sedone basin. Spatial SPI calculation results can help managers and
users capture areas of high drought potential instead of values at points with rain gauge data at the station.