Risk Assessment Of High Temperature Heat Damage To Mid-Season Rice In Hubei Under Climate Change

In recent years,changes in the global climate and its variability have exacerbated the occurrence and development of high-temperature disasters in Hubei mid-season rice,and have and will further jeopardize the safe production of rice in the region.In order to explore the high temperature stress risks of the rice under the current and the future climate transformations,which based on the the two typical concentration paths of RCP exported by the Had Gem2-ES(one of the GCMs)during the future time from 2021 to 2080,the 76 meteorologic stations in Hubei should be interpolated according to the bilinear interpolation and the data under the different surroundings and conditions should be revised and examined by the variance correction so that we can get more reliable simulated data.Due to the heat injury index,The current and future climate should be considered as the background condition when we put our study into the annual variation and the spatiotemporal structure about the middle rice in Hubei.We also offer the scientific evidences for local rice food safety production by constructing the risk assessment model of high temperature stress,setting up the divisions into districts for the heat injury risk of the mid-season rice in Hubei area.The verdicts are as follow:Firstly,the whole heat injury data searched in the Hubei province has been on the rise under the current climate change,especially the high frequency,intensity and the wide range characteristic since the beginning of the 21 century.The basic heat injury regularities of distribution in there is ranging from southeast and southwest low mountain area(the highest risk region),and the middle flat area(the secondary risk)to the northwest region(the lowest risk).Secondly,According to the statistical analysis of actual observation data,it is found that during the heading and flowering period of rice,the highest temperature at the four levels of34,35,36 and 37 ℃,the correlation between the seed setting rate and the accumulated temperature of the high temperature hazard at ≥ 35 ℃ is the best When it reaches 0.96,the high temperature mainly affects the seed setting rate of Hubei mid-season rice,resulting in a decrease in yield.Therefore,it is more suitable to choose the highest temperature of 35 ℃ as the index of high-temperature heat damage during the heading and flowering period of rice.Thirdly,under two kinds of future RCP,it will totally be on a rise about the hot temperature disaster risks on the rice,for the frequency,intensity,and the lasting days will be increased in the most areas of Hubei about its critical period of high temperature.Among these areas,the highest area lies in the southwest and the most southeast low mountain areas where the hot disaster will stay in the moderate-severe condition,what’s more,the intensity and the lasting days will increase obviously.The better area are the Jianghan plain and northeast area of Hubei where its degree of the disasters is mild and the intensity with its lasting days is lower than that low mountain areas while the best area is the northwest of Hubei where its hot disasters are decreasing.The amplitude of variation about the risk under RCP8.5 is higher than RCP4.5,and because of instability of RCP8.5.Finally,still under the two kinds of future RCP emission scenario,the mid-season rice will in a high heat injury risk in the fifth of heading of flowering in July.But with the time going by,the risk will be on a declining curve.Under RCP4.5 emission scenario,When we put off 5d,the risk will decline at 14.46%.If it is 10 d,the risk will lower at 32.13%,15 d by63.59%,and 20 d by 78.78%.However,Under RCP8.5 emission scenario,when we put off5 d,the risk will decline by 15.84%,10 d by 35.61% and 15 d by 56.63%,postponing 20 d will reduce the risk by 78.78%.The mid-season flowering period in northwestern Hubei is delayed by 10 days,the Jianghan Plain area is delayed by 15 days,and the northeast,southeast,and southwestern areas of Hubei are delayed by 20 days,which can greatly reduce the risk of high temperature heat damage of Hubei mid-season rice.