Rain-on-snow variation characteristics and its influencing factors in northern part of Northeast China
Based on the daily snow depth,precipitation and air temperature data during 1968-2019 from 121 stations in the northern part of Northeast China(NNEC),statistical methods were utilized to analyze the climatology,long-term change and impacting factors of rain-on-snow.Results showed that:the annual mean rain-on-snow day number in the NNEC ranges between 0.12-3.60 d,rain-on-snow is most frequently seen in the Changbai Mountains(1.34 d),Da and Xiao Hinggan mountains,with maximum values seen in the southern part of Changbai Mountains.Plateau and plain areas saw less rain-on-snow events,less than 0.83 da year.Rain-on-snow occurred in snow accumulating and melting season,peaking in October and April,more frequently seen in melting season than accumulating season,almost two times more frequent.Rain-on-snow saw a decreasing trend in all sub-regions in recent 52 years,Da and Xiao Hinggan mountains decreased significantly(climate tendency rate-0.107 d/10a and-0.105 d/10a,respectively,passing a significant test).The contribution of cold season rain day number and snow cover day number to rain-on-snow events showed spatial heterogeneity.Although rain day number is less in Da Hinggan Mountains,the snow cover day number and lasting day number is the largest in this area which is beneficial for rain-on-snow event,while in the Changbai Mountains a larger rain day number leads to more rain-on-snow events.On monthly scale,the increase(decrease)of rain day number and snow cover day number caused rain-on-snow event increase(decrease)in March(September).In April,the decrease of rain day number and snow cover day number contributed to the decrease of rain-on-snow events in Changbai Mountains,Songnen Plain and Xiao Hinggan Mountains.The decrease of the snow cover day number is the main cause for a rain-on-snow decrease in October.In the early stages of snow accumulating and melting(September and March)season,the common changes of rain day number and snow cover day number caused the rain-on-snow variation,while snow cover day contributed more in the late stages(October and April).Annual rain-on-snow day number and precipitation amount increased with increasing altitude.
northern part of Northeast Chinarain-on-snowchanging characteristicsinfluenc-ing factors
NETL
NSTL
万方数据
