Comprehensive Risk Assessment Of Main Agro-meteorological Disasters In Winter Wheat In Henan

Henan province is a temperate continental monsoon climate,uneven rainfall distribution,winter wheat is the main crop in Henan,in the growth and development process can occur drought,dry hot wind and late frost and other meteorological disasters.Drought can occur at all stages of winter wheat growth period,dry hot wind disasters occur at the stage of winter wheat filling and maturity,and the late frost damage mainly occurs after the jointing period of winter wheat.In this paper,based on 1962-2014 years' daily meteorological data and 1981-2014 years' growth period data of 14 stations in Henan Province,Through the establishment of index of drought,dry hot wind and late frost,the temporal and spatial distribution characteristics of the above three meteorological disasters were analyzed,and a comprehensive risk assessment model for meteorological disasters was established.Combined with vulnerability,exposure and regional disaster risk reduction,the main meteorological disaster risk assessment model of winter wheat in Henan province was established to evaluate the risk of major meteorological disasters in winter wheat in Henan province.GIS technology was used to draw the comprehensive risk zoning map of the main meteorological disasters in Henan winter wheat.The main work and conclusions are as follows:(1)Based on crop water deficit index to analyze the drought,winter wheat in Henan has a wide range of drought coverage,the rate of light drought decreased with the rate of 3.25/10a,and the rates of moderate drought,heavy drought and special drought were rising at the rate of 2.52/10a,0.68/1Oa and 0.47/10a respectively,among them,the light drought and moderate drought were the main,and the heavy drought was second,and the special drought was the least.The high frequency area of light drought was concentrated in south Henan and southwest of Henan Province.The moderate drought frequency were mainly in Xuchang,Shangqiu,Baofeng and Lushi;and the heavy and special drought occured mainly in the northern part of Henan.(2)Winter wheat dry hot wind occurred the number of days and sites were all more,taked lightly mainly.Light dry hot wind decreased at-0.51/10 a,and the heavy dry hot wind rised at a rate of 1.18/10 a.The light,heavy,and weighted dry hot wind averaged 0.8 d,0.3 d and 1.48 d per site per year.Dry hot wind occurred mostly in the north and middle of Henan.During 1980s to 1990s,the degree of dry hot wind decreased,and the dry hot wind was aggravated after 2000.(3)Late frost occurred in a wide range,with both light and heavy late frost showed a fluctuating decline and a low west-to-east trend.Lushi and Luanchuan were late frost recurrence areas,and the southern Henan were the lightest in late frost.In 1960s,late frost was the most serious,the number of occurrence of the whole area was 23.4/a,followed by 90s,the number of occurrence was 16.1/a,70 and 80s were 14.5/a,after 2000,the number of late frost was less.(4)In this paper,Based on the evaluation model of risk,vulnerability,exposure and disaster prevention and mitigation respectively,constructed a comprehensive risk assessment model of winter wheat in Henan.Among them,the high risk of drought was located in the north of Henan,and the low value area appeared in south Henan.Luanchuan and xixia were high risk areas for the late frost,and the low-value areas were distributed in southwest Henan and south Henan.The high risk area of dry hot wind was mainly in north Henan and central Henan,and gradually decreased in the southwest direction.In northern Henan,it was a high-risk area with multi-hazards comprehensive risk,and the risk decreased from north to south.The exposure gradually decreased from east to west;the highest vulnerability value was located in the west of Henan and southern Henan,while the northern and central regions were relatively low in vulnerability;the low-value areas for disaster prevention and reduction were scattered in the west of Henan and Xinyang,and the high value areas mainly in the northern nd central plains of the North,the high-value areas of major meteorological disasters were located in parts of Anyang,Nanyang and eastern part of Henan,and low-grade areas were distributed in Luanchuan,Xixia and Lushi.