Guangdong Drought Daily Dynamic Simulation and Evaluation Based on GIS

According to the concept of soil-moisture-balance in Palmer-drought-model,daily drought index(DDI) is defined by available water content(AWC) below level soil.AWC was simulated day by day using daily data of temperature and rainfall. Based on GIS technique and geographic correction model with 5 environmental factors of longitude,latitude,height above the level,grade and slope of terrain, drought spatial distribution with relative high resolution of 1 km was made from scatter data of DDI of 86 stations,which could reflect the effect of terrain factors to drought distribution with more detail.Combined land data,an operation system was developed to monitor and evaluate the occurrence,development,severity degree and distribution of the drought dynamically,and to provide decision-making and evaluation for manmade-rainfall operation.