Analysis Of Future Climate Risk Of Winter Wheat In Potential Northward Region In China

Daily meteorological station data from 1961 to 2010 and the future scenario data of RCP4.5scenario simulated by PRECIS were selected.Firstly,the potential northward migration area of winter wheat was identified as the research area by comparing the north boundry of winter wheat between1981-2010 and 2071-2097.The evalution of agro-climatic resources under RCP4.5 scenario in the potential northward region of winter wheat were analyzed in 2071-2097 based on the nine selected agro-climatic resources indexes.Then 3 types of freezing injury(severe temperature dowing in early winter,winter with long cold days and freeze-thawing)indexes and different drought indexes(SPEI in different month with different time scale)in 4 growing stages of winter wheat were selected to determined the temporal and spatial variations of freezing injury and drought disaster.Finnally,the risk of two disasters was anaylized respectively by using risk analysis probability.The results are as follows:(1)Climatic northern boundary of winter wheat would move northward 147.8 km in 2071-2097and possible planting area would increase by 1.86×105 km~2 and cultivated field is about 6.35×10~4 km~2relative to 1981-2010.Compared with the baseline(1961-1990),the light resource in potential northward region would have a decreasing trend;heat resource would significantly increase with an increasing variability in the last 30 years of the 21st century;precipitation resource shows an overall slight upward trend but with an increasing fluctuation;Light resource would decrease more in the northeast of study area,while less in the southwest;heat resource would increase more in southern area than northern part;water resource would manifest a more obviously increasing tendency in northeast of the research zone.Agricultural climate resources in the potential northward region of winter wheat demonstrated a better allocation in Dandong,Xiuyan in Liaoning Province and worse in Wengniute,Weichang,Youyu and Wuzhai.The area of adaptability region and not adaptability region was decrease,while there was an obviously increasing trend of second-rate climatic adaptability area in Shannxi and Ningxia province in south-west region where it used to be the second-rate climatic unsuitability area,compared with 1981-2010.(2)The effective range of freezing injury was winter with long cold days>severe temperature dowing in early winter>freeze–thawing during 2021-2097.The trend of severe temperature dowing in early winter is not obvious,while it was shown a decreasing tendency of winter with long cold days and a more volatile of freeze–thawing.The higher frequency region of severe temperature dowing in early winter was in Liaoning province,the higher frequency region of winter with long cold days was in north of researching area,freeze–thawing was in Taole and Yinchuan of Ningxia province.It was more likely to be suffered from one type freezing injury than two types and three types.In future,it was determined a decreasing trend of the risk of freezing injury in the potential northward region,especially about the area of highest risk.The higher risk of freezing injury was in Huanren,Zhangwu,Heishan,Chaoyang,Wenniuteqi,Chifeng,Fengning,Wuzhai and Yanchi,and the lower risk was in eastern of Liaoning,northern of Shanxi and southwest of researching area.(3)It was mainly occurred that during all of the growing stage(before sowing,green-up to heading,heading–mature,the whole growing season)it is more likely to suffer slight drought disaster and an increasing trend was shown,especially since 2080,the station proportion was increased obviously with an extended affected area in future.There was a different distribution of drought risk in researching area during different growing stage.The higer risk of drought before sowing was in southwest region,Wenniuteqi and chifengof Neimenggu,and fuxign of Liaoning province.The higer risk of drought during green-up to heading was in east of Liaoning and north of Heibei.The higer risk of drought during heading to mature was in Chaoyang,Wutaishan and Taiyuan,while the lower risk was in Weichang,Fengning,and Yanchi.The higer risk of drought during whole growing season was in Huanren,Anshan,Yuxian and Wuzhai,while lower risk was in Wenniuteqi,Chifeng,chaoyang,Chaoyang and Dandong.