| With the global warming,extreme climatic disasters have anomalously intensified.The areas affected by drought have also expanded,which has adversely impacted on the ecosystems and the sustainable economic and social development.As the largest winter wheat region in China,the growth of winter wheat production in Huang-huai-haiRegion is largely restricted by the frequent drought.Based on the natural disaster index method,this study constructed the Huang-huai-hai drought disaster risk model and applied ArcGIS software to carry out risk assessment and zoning of the winter wheat drought disaster in Huang-huai-hai Plain.The conclusions of the paper are as follows:(1)Using the crop water deficit index as a drought index,the spatial-temporal changes of drought in Huang-Huai-Hai Plain during 1981-2010 were analyzed.The results showed that the CWDI values in Huang-Huai-Hai area gradually increased from south to north,and the inter-decadal fluctuations in the 1990s were dramatic.There was a very severe global drought during the period from 1997 to 2000.The drought frequency basically followed the pattern of decreasing from north to south.The areas with higher frequencies were Baoding,Raoyang and Langfang in Hebei.(2)The linear moving average method was used to calculate the yield reduction rate of each region.The yield reduction rates in the south,the central and the north of Huang-Huai-Hai all decreased in the year of 1982,1988,1991,and 2000.Among the yield reduction years,the yield reduction in northern Anhui is a high value in the entire Huang-Huai-Hai region.(3)Based on the analytic hierarchy process and the weighted comprehensive evaluation method,the four impact factors of the drought risk assessment model were evaluated.Risk assessment of disaster-inducing factors indicated that the highest and second-highest risk areas were mainly located in southern Hebei,northwestern Shandong,northern Henan,and border areas of Henan,Anhui and Jiangsu.The low risk areas were located in the south of Huang-Huai-Hai region.Vulnerability assessment ofdisaster-pregnantenvironment showed that the highest and second-highest vulnerable areas were located at the junction of Hebei and Shandong,the junction of Shandong and Jiangsu,the junction of Henan,Anhui,and Jiangsu,and parts of western Henan.The low vulnerable areas were central Hebei,northern and central Henan,western Shandong and northern Jiangsu.Exposure assessment of the disaster-bearing bodies manifested that the highest and second-highest exposure areas were scattered and dotted,located in southwestern and eastern Hebei,northwestern Shandong,central and eastern Henan,and northern Jiangsu,The remaining areas were almost all low-exposed areas.Assessment results of disaster prevention and mitigation capabilities demonstrated that the areas with highest and second-highest disaster prevention and mitigation capabilities were located in eastern and central Hebei,central Shandong,southern and eastern Henan.The areas with low disaster prevention and reduction capability were located in Anhui and western Henan.(4)A comprehensive assessment of drought disaster risk in Huang-huai-hai was made based on the drought disaster risk index method.The spatial distribution of drought risk in Huang-Huai-Hai is complicated and the high risk values dot the north of Huang-Huai-Hai Region.The results showed that during the whole growth period,the highest areas were located in southern Hebei,northwestern Shandong,eastern and northern Henan.The second-highest risk areas centered on highest-risk areas and spread to the surrounding areas.The low risk areas were located in eastern Hebei,central and western Shandong,southern Henan and the south of Huang-Huai-Hai Region. |
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