Study of spatial and temporal distribution and multiple characteristics of drought and flood in Huang-Huai-Hai River basin

The Huang-Huai-Hai River basin is one of the important agro-ecological zones and major grain producing areas in China. The spatial distribution and temporal variations of drought and flood affected areas are analyzed using the daily precipitation time series for 1961-2010, the national 1:250 000-scale digital elevation model (DEM) model, and a 1:200 000-scale land use dataset. Precipitation data is collected from 204 meteorological stations distributed in the Huang-Huai-Hai River basin and its surrounding areas. The data is used to calculate the China-Z Index for measuring drought severity. The calculated China-Z Index is further corrected using an underlying surface correction procedure and is analyzed using the Set Pair Analysis (SPA) meteorological diagnostics routines. Maps of drought and flood prone areas are obtained and the regions with alternating dry-wet conditions are identified. The result shows that drought and flood are most likely to occur during summer and autumn seasons. There is a clear upward trend in the drought affected areas in autumn. Both Yellow River basin and Haihe River basin are prone to drought, while the Huaihe River basin often experiences both drought and flood disasters. The regions with alternating dry-wet conditions are gathered around the middle and upper reaches of Huaihe River.