Assessment of Precipitation and Drought Variability in Weihe River of China Over the Period 1960-2010

Abstract:

The amount and distribution of precipitation play crucial roles in the occurrence of drought in the Weihe River Basin (WRB) of China. Using the precipitation data (1960-2010) of 21 meteorological stations, the spatial and temporal characteristics of droughts were examined by using theory of runs and the Standardized Precipitation Index on 3-month, 6-month and 12-month time scales. The results showed that the main drought type was moderate drought, and drought occurred frequently on July and October. During the last 50 years, the drought intensity and frequency were the biggest in 1991-2000. According to the SPI-3, the risk of spring and fall drought increased gradually, which could impact on agriculture and water supply. The trend of SPI values over the time period was calculated and analyzed, showing of increasing dryness throughout the basin, and the north and northwest zones of WRB were most likely to suffer from drought. Also, compared with the east, the drought severity and drought duration in the northwest was more serious. It was also observed that there was strong relation between precipitation distribution and drought zones in the basin, and the drought conditions changed continuously with seasons depending upon precipitation amount and its spatial distribution.