Basic Features Of Atmospheric General Circulations Related To Anomalous Winter Snowfall In The Yangtze-Huaihe River Basin And Its Possible Linkages With The Autumn Arctic Sea Ice

Based on daily meteorological data contained in the Daily Surface Climate Dataset for China(V3.0)during the period 1960-2012,the temporal and spatial characteristics of winter snowfall in the Yangtze-Huaihe River Basin(YHRB)of China and its atmospheric general circulations,possible linkages with autumn Arctic sea ice are analyzed based on correlation analysis,regression analysis,synthesis analysis and other statistical methods,by using the double threshold method of Ding et al.(2014)to compare the wet bulb temperature and the critical temperature to select the daily snow amount.The main conclusions are as follows:(1)The winter snowfall in the YHRB region is large,with heavy snowfall intensity and frequent small snowfall.Snowfall mainly comes from snowstorm.The winter snowfall in YHRB is mainly concentrated in January and February,but less in December.that winter snowfall in the YHRB exhibits consistent anomalies over the whole region for the interannual variation during 1960–2012.The large value areas of snowfall mainly concentrate in the range of 27°N to 32°N.There is obvious interannual variation characteristics,and no significant decreasing trend from 1960 to 2012.(2)The snowfall in the winter YHRB is closely related to the anomalies of the atmospheric circulation in the same period.Further analysis suggested that winter snowfall anomalies in the YHRB are closely linked to anomalous wintertime Scandinavian(SCAND)Atmospheric Teleconnection Pattern anomalies.When there is more winter snowfall in the YHRB,the SCAND pattern is usually in a positive phase,accompanied by a strengthened Urals blocking high and East Asian trough,which is conducive to strengthened cold-air activity,intensified vertical motions,and more water vapor transport in the YHRB.In contrast,less winter snowfall in the YHRB usually happens in a negative phase of the SCAND pattern.(3)The autumn Arctic sea ice has the opposite phase distribution between the North Pacific Basin and the Atlantic Basin in the Arctic,which is closely related to the winter SCAND pattern and the winter snowfall in the YHRB.In the high SICI years,i.e.the Greenland-Barents sea ice is more and the Lapjev sea ice is less,the atmospheric circulation anomalies mainly show as the positive phase of the SCAND and the weakening of zonal westerly winds,which is conducive to the southward movement of high-latitude cold air,the near-surface Eurasia is cold anomaly,and the cold anomaly of temperature extends to the YHRB.The cold air from the North and the warm,humid airflow from the tropics are converged and rised,resulting in more snowfall in the YHRB.