Evolution characteristics analysis of meteorological drought based on GIS

Based on 1977-2010 precipitation data of 38 weather stations in the Lancang-Mekong River basin, evolution characteristics of meteorological drought was analyzed using Standardized Precipitation Index (SPI) with the spatial analysis and statistics functions of Geographic Information System (GIS). The results show that drought intensify and occurrence area changed insignificantly in wet season. But in dry season, drought intensify and occurrence area have been decreasing significantly. Barycenter position of drought intensity and drought frequency in wet season changed southeastward, with both latitude and longitude changed no more than 1°. Barycenter position of drought intensity and drought frequency in dry season changed northwestward, with range of changes greater than that in wet season. For both drought intensify and drought frequency, the range of changes was greatest in recent 10 years.