Characterization Of The Response Of Precipitation Composition To Climate Warming In Heilongjiang Province

Northeast China is one of the regions with the most significant global monsoon climate,and its precipitation characteristics may appear unique in the context of climate warming.Heilongjiang province in northeast China is located in the middle and high latitudes,with significant warming,and temperature is the main factor affecting precipitation,while the current contradiction between food security and water shortage is increasingly prominent.As a major grain producing area in China,it is particularly important to systematically study the changes of precipitation characteristics and its relationship with temperature in Heilongjiang Province in the context of climate warming.In this paper,we analyzed the spatial and temporal variation characteristics of precipitation composition in Heilongjiang Province using day-by-day precipitation and temperature data from 1961-2016 at 58 meteorological stations in Heilongjiang Province,and also analyzed the influence of temperature on precipitation composition in the context of climate warming.The following conclusions were obtained.(1)In precipitation composition,the snowfall and snow-rain ratio in Heilongjiang Province showed an increasing trend from 1961 to 2016,and the proportion of snowfall to total precipitation increased by 3%;spatially,the increasing trend was more obvious in the east,and compared with the 1960 s,the snowfall in the eastern part of Heilongjiang Province was equivalent to an increase of 58%,and the snow-rain ratio increased by5.17%.The significant increase in snowfall in the east was the cause of the increase in the snow-rain ratio in the province,and there was no significant trend in both total precipitation and rainfall.Precipitation frequency composition,the province's total precipitation frequency,rainfall frequency,snowfall frequency,snow and rain frequency ratio spatial and temporal are not significant changes.(2)In the composition of rainfall,there is no significant spatial and temporal change in Heilongjiang Province from 1961 to 2016.In the composition of rainfall frequency,only the frequency of light rain in the eastern region spatially showed a significant decreasing trend,and the proportion of medium rain increased and the proportion of light rain decreased temporally.(3)In the composition of snowfall,temporally the amount(or proportion)of heavy snowfall and medium snowfall showed an increasing trend,and the proportion of light snowfall showed a decreasing trend;spatially,the change characteristics of the east and west of Heilongjiang Province showed differences,and the change in the eastern region was more significant,mainly showing an increasing trend of heavy snowfall and heavy snowfall,and a decreasing trend of light snowfall,while the western region mainly showed an increasing trend of light snowfall.In the snowfall frequency,the frequency(or proportion)of heavy snow and medium snow show an increasing trend in time,and the proportion of small snow shows a decreasing trend;spatially,the same changes in the east and west are more different,specifically the frequency(or proportion)of heavy snow and large snow show an increasing trend in the eastern region,and the frequency(or proportion)of small snow shows a decreasing trend,while the frequency(or proportion)of medium snow in the western region showed an increasing trend.(4)From 1961 to 2016,the annual,summer and winter temperatures in Heilongjiang Province showed a significant upward trend,and the temperature increase in winter was greater than that in summer,and the warming trend in the north was greater than that in the south.Correlation analysis shows that there is a significant correlation between air temperature mainly and the frequency of snowfall,and the increase in air temperature decreases the frequency of light snow,increases the percentage of heavy snow and moderate snow,and decreases the percentage of light snow.The mutation analysis shows that the increase in temperature has a greater impact on the amount and frequency of heavy and medium snowfall,and the proportion of the frequency of heavy,medium and small snowfall,and a smaller impact on other indicators.(5)From the different levels of snowfall initial and final days of change,both the initial and final days have a trend of advance,while the final day of medium snow and the initial day of light snow show a delayed trend;but the initial and final days of light snow show a significant delay and advance respectively.Impact of heavy snow and heavy snow in eastern Heilongjiang Province,and the water vapor trajectory from the Sea of Okhotsk shows a significant increasing trend,and the increase is more obvious after the21 st century.