| The impact of drought and flood on crop yields is increasingly serious on the background of global climate change.This paper selects four areas(Cuiping District of Yibin City,Dongxing District of Neijiang City,Gaoping District of Nanchong City and Bazhou District of Bazhong City)in the hilly area of central Sichuan as the research area.According to the precipitation and temperature data of four areas for nearly 37 years(1980-2016),this paper researches the changes in climate of the hilly area of central Sichuan.According to the precipitation data of four areas for nearly 37 years(1980-2016),with the Z-index method,this paper divides the drought and flood level of the interannual,seasonal and growth periods of four crops(wheat,rice,corn and rape)separately,and analysis the dynamic characteristics of drought and flood of the hilly area of central Sichuan.According to the yield data of the four main crops in the hilly area of central Sichuan in the past 20 years(1997-2016),this paper uses regression analysis method to obtain trend yield,then gets the meteorological production,and researches the relationship of dynamic characteristics of drought and flood and meteorological production.The main conclusions of this paper are as follows:(1)Characteristics of climate change in the hilly area of central Sichuan for nearly 37 years(1980-2016): there is climate warming trend in the hilly area of central Sichuan for nearly 37 years.The temperature rises obviously in Cuiping District of Yibin City and Gaoping District of Nanchong City,while less in Dongxing District of Neijiang City and Bazhou District of Bazhong City;there is a concussion decline in precipitation and the feature of interannual volatility is significant.(2)Dynamic characteristics of drought and flood in the hilly area of central Sichuan for nearly 37 years(1980-2016):?From a perspective of interannual feature,the hilly area of central Sichuan was partial flooded in 1980 s and partial droughty in 1990 s and early 21 st century and partial flooded after 2010.The order of frequency of drought from high to low is Dongxing District of Neijiang City,Gaoping District of Nanchong City,Bazhou District of Bazhong City and Cuiping District of Yibin City.The order of frequency of flood from high to low is Dongxing District of Neijiang City,Cuiping District of Yibin City,Gaoping District of Nanchong City and Bazhou District of Bazhong City.The severity of large flood and large drought is smaller,but the frequency is higher;the severity of extreme flood and extreme drought is bigger,but the frequency is lower.?From a perspective of seasonal feature,the drought and flood alternates in each season in the hilly area of central Sichuan.Spring and winter drought is more serious,floods occur frequently in summer and autumn.Spring drought is more serious in 1983-1984 a,2000-2001 a and 2014-2016 a.Summer drought is particularly serious,extreme drought occurred in the hilly area of central Sichuan in summer of 2006.It is in an alternating state of drought and flood in autumn,and it has been dominated by floods since 2010.The drought is particularly serious in the winter of 2008 and 2009.The droughts and floods are more serious in Cuiping District of Yibin City and Bazhou District of Bazhong City,and the degree of drought and flood is relatively low in Dongxing District of Neijiang City and Gaoping District of Nanchong City.?From the perspective of crop growth period,in the growth period of wheat,drought and flood alternates apparently and extreme droughts and floods often occur.The order of frequency of drought from high to low is Gaoping District of Nanchong City,Dongxing District of Neijiang City,Bazhou District of Bazhong City,Cuiping District of Yibin City.The order of frequency of flood from high to low is Cuiping District of Yibin City,Bazhou District of Bazhong City,Gaoping District of Nanchong City,Dongxing District of Neijiang City.In the growth period of rice,the order of frequency of drought from high to low is Cuiping District of Yibin City,Bazhou District of Bazhong City,Gaoping District of Nanchong City,Dongxing District of Neijiang City.The most frequent occurrence of flood is Dongxing District of Neijiang City and Bazhou District of Bazhong City,and then Gaoping District of Nanchong City,the least is Cuiping District of Yibin City.In the growth period of corn,the order of frequency of drought from high to low is Cuiping District of Yibin City,Bazhou District of Bazhong City,Dongxing District of Neijiang City and Gaoping District of Nanchong City.The order of frequency of flood from high to low is Dongxing District of Neijiang City,Gaoping District of Nanchong City,Bazhou District of Bazhong City,Cuiping District of Yibin City.In the growth period of rape,the order of frequency of drought from high to low is Cuiping District of Yibin City,Gaoping District of Nanchong City,Bazhou District of Bazhong City,Dongxing District of Neijiang City,the order of frequency of flood from high to low is Bazhou District of Bazhong City,Gaoping District of Nanchong City,Dongxing District of Neijiang City,Cuiping District of Yibin City.(3)Dynamic characteristics of drought and flood in the hilly area of central Sichuan for nearly 37 years(1980-2016):The dynamics of drought and flood have a relatively complicated impact on four crops yield in the hilly area of central Sichuan.Over all,as the degree of drought and flood increases,the fluctuation of meteorological production increases,indicating that its impact on crop yields is greater.Floods,especially extreme flood and large flood have a significant impact on yield reduction of wheat and corn,while extreme drought and large drought have a significant impact on yield reduction of rice and corn.Rape production is less affected by drought and flood. |
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