Prediction Of Drought Disaster Risk For Winter Wheat In Hebei, Shandong And Henan Based On CMIP5

Winter wheat is the main grain crop in China and has an important strategic position in food security.Under global warming,precipitation will be redistributed in space and time,and the drought situation in China will become more complicated.In the future scenario,the change of drought disaster risk in China's main winter wheat producing provinces(Hebei,Shandong and Henan)is the core issue of China's future food security.However,limited by data resolution,less attention has been paid to the future risk projection of local winter wheat.Therefore,this paper took the main winter wheat producing province as the research area,and estimated the drought disaster risk under future scenarios based on the CMIP5 downscaling data.The main contents of this paper included: analysis of the spatial and temporal characteristics of drought during the sowing-harvest period of winter wheat;construction of a drought disaster risk assessment model for the main winter wheat producing provinces;model simulation assessment of precipitation and average temperature;risk projection of drought disasters under the RCPs.The main conclusions are as follows:(1)Based on the SPEI drought index,it was found that mild drought occurred most frequently and had the broadest impact in the study area,and the station ratio of severe and extreme droughts is increasing.The spatial drought distribution types of different levels were different,with slight droughts concentrated at the intersection of the main producing provinces.The high-value centers of moderate droughts were located in eastern Shandong and southwestern Henan,while extreme droughts were located in northern Henan.The weights of drought risk indicators were determined by analytic hierarchy process,and a drought disaster risk model based on the hazard,exposure,vulnerability as well as disaster prevention and mitigation capacity was constructed.The results showed that the drought risk decreases with the increase of latitude,and the high-value centers were located in southwestern Henan,while the low-value centers were located in eastern Hebei.(2)The spatial and temporal characteristics of precipitation and mean temperature were evaluated using downscaled data from 21 CMIP5 models based on qualitative Taylor diagram and quantitative Taylor index analysis methods.The results showed that the simulation effect of precipitation and mean temperature in climate state is better than the standard deviation.The simulation effect of mean temperature on interannual variability is better than precipitation,but worse for spatial distribution of interannual variability.Finally,a multi-model ensemble weighted model was constructed based on the models' comprehensive ranking,which simulated slightly better than the simple ensemble average and simple weighted models.(3)With further global warming in the future,precipitation and mean temperature will both increase,while SPEI will decrease,which indicates an overall tendency toward drought in the main winter wheat producing provinces.The relative contributions of precipitation and mean temperature have great spatial variability.In high latitude areas,the effect of evapotranspiration of temperature is greater than precipitation,which increases the risk of drought.On the contrary,in low latitudes,the effect of precipitation is greater than evapotranspiration,which reduces the risk of drought.Compared with the RCP4.5 scenario,the intensity and scope of drought disaster risk under the RCP8.5 scenario will increase,especially at the end of this century,and the future drought risk will display obvious high-latitude characteristics.