Study On The Change Law Of Climate Driving Factors Of Freeze-thaw Erosion In Black Soil Area Of Northeast China

The soil structure was damaged by freezing-thawing in the black soil area of northeast China,which intensified the soil erosion during thawing period.The effects of autumn rainfall on initial moisture content,as well as the foundation of the runoff in winter and spring precipitation and temperature changes,will aggravate soil erosion,which is affected by climatic conditions.However,it is not clear that the effects of climate driving factors on soil erosion in thawing period are not clear.Therefore,this study proposed by collecting the northeast black earth area 120 weather stations in recent 55 of precipitation and temperature data,extract the influence of frozen soil,soil freeze-thaw cycle and frost free period the climate elements of snowmelt erosion(water),by spatial interpolation,linear regression analysis,the M-K mutation methods of inspection,analysis the elements of space distribution characteristics and the trend of change over time,climate is analyzed on the driving factors of soil erosion of the northeast black soil area at the spring thawing period,the influence of the main conclusions are as follows:(1)the climatic factors that affect the soil freezing include three indexes: winter average temperature,annual temperature difference and autumn precipitation.The average temperature in winter is the main factor affecting the depth of soil freezing,and the average temperature of winter in the black soil region of northeast China is decreasing from south to north.The average temperature of the five typical stations showed an upward trend in winter,indicating that the soil freezing in the black soil region had a tendency to decrease under the influence of winter average temperature.The temperature year is less than that of the soil freezing depth.The annual temperature difference of the five typical stations showed a decreasing trend,indicating that most black soil regions had a decrease in soil freezing depth under the influence of the annual temperature difference.The main effect of precipitation in autumn is the pre-freezing soil moisture content,and the precipitation in autumn in the northeast black soil area is low in the south and north.Five typical station in jilin province mei estuaries and Inner Mongolia sauron autumn rainfall increases,while in changchun,jilin,heilongjiang that is suihua and nenjiang autumn precipitation decreased,that is affected by autumn rainfall northeast black soil area at the area of the freeze effect weakened.According to the change trend of three climatic factors,the soil freezing degree of black soil area in northeast China is decreasing.(2)influence the climate of thawing period freeze-thaw erosion factors mainly choose the spring temperature diurnal range 0 ? change frequency and temperature.The temperature difference reflects the freeze-thaw temperature difference of the soil during thawing period.The temperature difference between the five typical stations in March and may showed a decreasing trend,indicating that the freezing and thawing erosion in the black soil area of northeast China decreased during the spring thaw period.Around0 ? temperature change frequency reflect intuitive freeze-thaw cycles,the same as the western region is higher than the eastern region;Five typical station in heilongjiang that is suihua and nen river,InnerMongolia,jilin changchun freeze-thaw cycles will decrease trend of number of freezing and thawing JiLinMei estuary increasing trend,shows that the northeast black earth area overall decrease freeze-thaw cycles,parts of increase.Overall,the freezing and thawing effect of spring thaw in the northeast black soil area of 55 a is weakened.(3)the climate driving factors that affect the erosion of melting snow(water)are selected to study the winter precipitation,spring precipitation and spring temperature rise rate.Snow accumulates in winter,and thawing of the snow directly or indirectly accelerates soil erosion.Winter precipitation in the southeast,northwest side of high,middle low;Except parts of central snowfall slightly less snowfall in most regions of increased to some extent,explain much affected by the snow in winter in melting snow period increased with soil erosion intensity.Spring precipitation increases soil erosion by direct or indirect increase of surface runoff,and the average precipitation in the whole black soil area decreases from south to north in spring.Five sites in jilin changchun station spring precipitation showed a trend of decline and four other sites in the spring precipitation all showed a trend of increase,sauron station significantly increased in the west and is affected by the spring precipitation in many parts of the black soil area of soil erosion,increase trend in western is most obvious.A rise in spring temperatures will accelerate the rate of snow melt and increase soil erosion.The snowmelt date of the whole black soil area was early,and the initial temperature of the melting snow decreased,and the rate of warming of the whole black soil was accelerated.Under the influence of melting snow(water)erosion,the soil erosion in the thaw period increased.