Variability of heavy and little snowfall in the south and north of the Qinling Mountains under the background of global warming
A striking warming trend has triggered extreme weather and events in the regions worldwide.Snowfall is an important indicator of climate change,changes in snowfall at different levels reflect the integ-rated response of global warming to the trends in key climate variables and extreme events,and significant geo-graphical variation exists in the response pattern of snowfall in different levels across regions.Mountainous areas are highly sensitive to climate change.As an important geographical demarcation line between the north and south of China,the Qinling Mountains belongs to China's snow-frequent belts,a sensitive area under cli-mate change.Based on the daily data from the 72 meteorological stations,we analyzed the spatio-temporal variation of heavy snowfall and light snowfall during November-March of the following year in the south and north of Qinling Mountains from 1970 to 2018,using the method of the wet bulb temperature dynamic threshold and trend analysis.Moreover,we assessed the relationship between the snowfall and temperature in three sub-regions(Guanzhong Plain,south slope of Qinling Mountains and Hanjiang Valley).The results show that:1)From 1970 to 2018,the number of rainless days increased,and the solid precipitation decreased obvi-ously during November-March of the following year in the south and north of the Qinling Mountains.The number of snowfall days decreased from 8.5％to 5.2％in the previous period after 1998,and the proportion of sleet days decreased from 1.2％to 0.6％.2)The response patterns of snowfall to climate change varies from snowfall in different levels.The snowfall amount and snowfall days of light snowfall decreased significantly,as well as intensity of light snowfall increased significantly.However,there was no clear linear increasing tendency in the snowfall amount,snowfall days and intensity of heavy snowfall,which indicates that the change of snowfall in the transition zone between north and south of China is dominated by the decrease of light snow.3)In terms of the response to the temperature,the snowfall amount and days of light snowfall in the three sub-regions were significantly negatively correlated with temperature changes(P＜0.05).Similar results were observed in the snowfall amount and days of heavy snowfall days in Guanzhong Plain and Hanjiang Val-ley.Meanwhile,three indexes of heavy snowfall were weakly correlated with the temperature of the south piedmont of the Qinling Mountains.Both Guanzhong Plain and Hanjiang Valley are the sensitive area the re-sponse of heavy snowfall to the temperature.The findings of this research can provide a theoretical basis for better understanding the winter climate response pattern in winter in the transitional zone between the north and south of China.
climate changeheavy snowfallsnowfall/rain discrimination methodsouth and north of the Qin-ling Mountains
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