Abstract: Drought is one of the most common natural disasters. Researches on the change pattern of extent and severity of drought have a positive significance to the studies on drought prevention and ecological change. The study area for this research is the “Three-river Headwaters” region in China. Tropical Rainfall Measuring Mission (TRMM) remote sensing data during the period from the year 1998 to 2010 and meteorological raingauge data were used to calculate and analyze the values of standardized precipitation index (SPI) for the study area. The time series of 10-year drought conditions and the spatiotemporal change of drought were analyzed. High accuracy was achieved by integrating the TRMM data with SPI, which was demonstrated that this method was of practical significance for the study area.

Key words: TRMM, standardized precipitation index, drought, spatiotemporal change, “Three-river Headwaters”region