Temporal And Spatial Distribution Characteristics And Trends Of Rainstorm Disasters In Huanghuai Plain

To study law and development of waterlogging disaster on Huanghuai plain under the background of global warming,this article selects combination of the ten-day waterlogging index short-term and long-term I index as the he rain waterlogging index,analyzed the Huanghuai plains within 39 national data from 1961 ~ 2017 year after year,month by month rain waterlogging disaster frequency,get the following conclusion:(1)Line from RiZhao through the interpretation of weifang and YiYuan to the Yellow River as dividing line,divided Huanghuai plains to two parts-the peninsula area and the body area.In the peninsula area,waterlogging probability in spring,autumn,winter has a law of being more little from the northeast to southwest;waterlogging probability in the whole year reduce gradually from west to east.In the main area,the probability of waterlogging in spring,autumn and winter is much less than that in the northeast,and the probability of waterlogging in the whole year decreases gradually from northeast to southwest.(2)Key zone having the rain waterlogging probability Higher than 95% is located along the Huai River,and extended gradually with the month,to the most of Huanghuai plain in June,July and August for all,to southwest back in September,October,back to the west of XiXia,disappear in November.The flood disaster in Huanghuai plain is concentrated in April to October.(3)Huanghuai plain can be divided into five types of regions by single factor clustering of annual waterlogging probability,and into seven types of regions by multi-factor clustering of annual and mensual waterlogging probability.Compared with thesingle factor clustering results,it is better to use multi-factor clustering to divide the waterlogging area of Huanghuai plain.(4)In the peninsula region,the annual waterlogging did not separate out the significant influencing factors.The significant factors in January,February,November,December were the latitude,the longitude in March,and the comprehensive sea level in June.Linear fitting equation: January is y1=-0.015x+1.557,x is continental;February is y2=6.383x-3.077,x is latitudinal sine value;March is y3=0.037x-3.693,x is longitude;June is y6=-1.011E-7x+0.971,x is comprehensive ocean degree;November is y11=3.685x-1.323y11=3.685x-1.323,x is latitude positive chord value;12 is y12=6.257x-2.914,x is latitude The sine value.(5)In the main area,the annual waterlogging is significantly affected by the latitude,and the main monthly influencing factors are latitude,followed by longitude,and also related to normal sea level in April and August.The linear fitting equation:January is y1=-2.793x+2.322,x is latitude sine value,February is y2=-0.030x+1.796,x is latitude;March is y3=-0.047x+2.461,x is latitudes;April is y4=-0.032x+2.013,x is latitude;May is y5=-0.838x+1.417,x is latitude sine value;July to y7=0.003x+0.634 x is longitude;August is y8=-0.001x+0.994,x is common ocean degree;October is y10=-0.014x+2.483,x is longitude;November is y11=-0.01x+2.040,x is longitude;December is y12=-1.391x+1.572,x is latitudinal sine value.(6)The annual waterlogging frequency in Huanghuai plain fluctuates with the annual fluctuation,and it tends to increase with the generation.The number of waterlogging in the Huanghuai plain increased with the annual fluctuation in January,and the number of floods in April and October decreased with the inter-annual fluctuation,with the same trend as the intergenerational trend.The annual variation trend of the seven types of regions is different from that of the monthly change trend,and the annual trend characteristics of different regions are also different.It is better to analyze the annual variation trend of the annual waterlogging.(7)During the period from 4 to 10 months being as the key period of waterlogging,the fluctuation amplitude of waterlogging station in April to July gradually decreases with the month,and gradually increases from August to October,but only in July has a stable period of 15 years.In Huanghuai plain,amplitude of waterlogging station is more than 80% of the plain in April,May and October,more than 90% in June and September,more than 95% in July and August.