Effect Of Temperature And Radiation On Snowmelt Runoff In Songhua River Basin

Snowmelt runoff is an important freshwater resource in Northeast China.It has an important impact on spring farming water,river inflow,and reservoir water storage planning.It mainly depends on snow accumulation and snowmelt climate changes.Temperature and radiation changes are important for spring snowmelt.However,at present,there are few studies on snow cover and climate change impacts on snowmelt runoff in Northeast China,and they are not systematic enough.Therefore,this paper takes the Songhua River Basin as the research object,uses satellite and station data,and uses a variety of mathematical methods and software to systematically study snow,weather,and runoff in the Songhua River basin from 1979 to 2015.The dissertation focuses on the spatio-temporal changes of snow cover in the study area and the response trends of regional temperature and radiation to global climate change,and on this basis focuses on the analysis of snowmelt temperature and radiation changes on the macroscopic processes of snowmelt runoff.The study of passive microwave remote sensing snow cover data shows that in the Songhua River Basin in the past 37 years,the annual snow cover changes greatly,and the snow depth as a whole shows an upward trend.The number of snow days was between 176d-230 d,showing a downward trend overall,mainly concentrated in November of that year to March of the following year.Seasonal stable snow cover area accounted for 81.31% of the total drainage area.The number of snow days and snow depth showed an opposite trend in terms of interannual variation,and they were basically the same in spatial distribution.The high value areas were mainly distributed in the upper reaches of Nenjiang River in the northern part of the basin,followed by the Songhua River(below the Sanhe Estuary)and the second in the east.In the Songhua River basin area,the values in the lower reaches of the Nenjiang River in the southwest are lower;During the study period,the average temperature of the Songhua River and the three sub-basins generally showed a trend of warming.The average temperature in each area has increased significantly since the end of the 1980 s.It has declined after entering the 21 st century,with the most significant decline in winter.The average temperature and annual temperature increase rate for many years are not much different,and the temperature changes are generally the same.The average temperature of the rivers in the four seasons has abruptly changed.The annual mean temperature has increased in 1989.Spring and autumn have mainly occurred in the late 1980 s.Summer mainly occurs in the mid to late 1990 s.Winter mainly occurs in 21 years.The beginning of the century.The spatial variation of air temperature varies greatly among different regions,among which the temperature increase rates in Xiao Er Gou,Harbin,Dunhua and Songjiang are relatively high,and the areas in the southwest of Fujin,Jiamusi,Tailai and the second Songhua River basin are relatively low.The average annual total radiation of the Songhua River basin is 13.42 MJ/m2,showing no significant increase as a whole.In addition to the declining trend in the mainstream of the Songhua River,the remaining two sub-basins are up-swing but not significant.In the sub-basin,the daily total amount of radiation in the Nenjiang River Basin is the largest,followed by the Second Songhua River Basin,and the Songhua River Main Stream is the smallest.The total amount of daily radiation showed a regular increase-decrease change during the year,which was the largest in June and the smallest in December.The spatial distribution of radiative energy is represented by the low height of the west,the height of the south and the height of the north.The average daily radiation output of stations: Soren> FusionExcel> Changchun> Yanji> Harbin> Heihe> Jiamusi;From 1979 to 2010,the annual runoff of the Songhua River basin and the snowmelt runoff in the spring showed a downward trend at different levels.The snowmelt runoff accounted for an increasing trend in the total annual runoff,and the main stream accounted for more than the tributaries.The order of the regions is: Jiamusi Station> Harbin Station> Jiangqiao Station.Both the start and end times of the snowmelt were advanced,and the snowmelt end time was 14.59 days ahead of schedule.The snowmelt duration was significantly reduced and was reduced by 11.4 days during the study period.The results of grey correlation analysis show that the correlation between radiation and snowmelt runoff is greater than the degree of temperature correlation during the snowmelt period.When the temperature and radiation change 1%,the snowmelt runoff changes can be caused by 0.23% and 0.57%,respectively.This article innovatively analyzes the influence of temperature and radiation changes in the Songhua River watershed on snowmelt runoff,and explores the interrelationship between snow-meteorological elements-melt snow runoff,providing a theoretical basis for fully understanding the climate change and the characteristics of runoff in the Songhua River Basin.