Analysis on the spatial-temporal change characteristics of flood and drought disasters in China during 1950-2005

The paper is intended to analyze the temporal change and spatial distribution of flood and drought disasters during the period from 1950 to 2005 in China based on the GIS (Geographic Information System) spatial analysis methods. The data for the analysis includes statistical data of the flood and drought disasters which are suffering area and affected area and spatial geographical data of China which are 1:1000 000 province boundary vector map. The spatial data obtained from National Natural atlas published by Institute of Geographical sciences and Nature resources research, CAS. The flood disaster data are gathered from China Hazard Report in 1949-1995 and China Statistical Yearbook compiled by National Bureau of Statistics of China. By analysis of the temporal change and spatial distribution of flood and drought disasters, it can be seen that Flood and drought disasters increased in the research period. Before the middle of 1980s flood and drought disasters had lower and influenced area increased evidently after the middle of 1980s.The indicated that China flood and drought were expanded on the whole situation and stabilizing, this demonstrates China floods and droughts continued on the trend of expansion. China's major flood occurred in the South, the North and floods occurred in both the frequency or intensity was much smaller than the South, China's major drought occurred in the north. The affected rate and suffered rate for flood and drought disasters are positive correlative. This indicates the resistance capacity of agriculture system in China is faintish in general.