Integrated assessment for meteorological and hydrological drought of southern taiwan

In recent year, droughts have become more intense and frequent in humidity level distinct regions like Taiwan. Due to global warming, the water resources will continue to decrease and the frequency of drought will increase. There are many drought indices proposed to assess the different drought types. The main purpose of this study is to assess the drought of southern Taiwan by constructing an integrated assessment based on the Standardized Precipitation Index (SPI) and the Streamflow Drought Index (SDI). The results show that: (1) The results of SPI and SDI series for periods of twelve months (November-October) is similar and consistent. Severe and extreme drought events were indicated in 1979-1980, 1992-1993, 1994-1995 and 2001-2003. (2) There is a significant drying trend of the drought in the Ailiao River Basin and showed a downward decrease of 33%. (3) The integrated drought assessment (SPI-SDI) meets the climatic characteristics of southern Taiwan and different seasons show different drought patterns. Therefore, confirming the use of a single index cannot comprehensively reflect the characteristics of a regional drought, only by using various drought indices can both analysis and description of the regional drought characteristics be more completely, also enhance the accuracy of drought analysis.