The Possible Influence of Atmospheric Circulation and North Atlantic Sea Surface Temperature Anomaly on the Winter Cold Wave Frequency in the Southern China

Based on the daily minimum temperature station data provided by the National Meteorological Information Centre from 1980 to 2022， the month-by-month reanalysis data of the NCEP/NCAR， and the monthly Sea Surface Temperature （SST） data from the NOAA， by using EOF， simple linear regression and T-N wave flux methods， the main anomalous spatial and temporal characteristics of winter cold wave frequency in the southern China are studied， and the influence mechanisms of atmospheric circulation and winter Atlantic Sea Surface Temperature Anomaly （SSTA） on it are also analyzed.The results show that： （1） The large value areas of winter cold wave frequency are mainly located in the eastern and central of the southern China， with an approximately "inverse C" distribution.There are three main frequency anomalous modes， namely， regionally consistent anomaly， north-south antiphase anomaly and tripole anomaly patterns according to the EOF analysis， among which the regionally consistent anomaly reflects the overall anomalous spatial and temporal characteristics of the winter cold wave frequency in the southern China.（2） The negative phase of the North Atlantic Oscillation （NAO）， the strong Caspian Sea - Tibetan Plateau ridge and the East Asian Trough located to the north and to the east， the weak in the north and strong in the south of the Siberian High， the strong temperate jet and the weak subtropical jet are the key circulation systems affect the winter cold wave frequency in the southern China.The cold air pool is located in the Western Siberia.The high and low level circulation systems cooperate together to make the cold air from Western Siberia move southward to the vicinity of the Caspian Sea， and then transport eastward along the northern side of the Tibetan Plateau， then move southward into the southern China along the eastern side of the Tibetan Plateau， resulting in the increase of the winter cold wave frequency in the whole southern China.（3）In winter， the “+”“-”“+” tripolar SSTA in the North Atlantic can stimulate the -NAO atmospheric circulation anomalies through the exchange of heat fluxes between air and sea and the Rossby wave energy anomalies.The Rossby wave energy propagates from the North Atlantic to East Asia along the south and north two paths， and stimulates the corresponding anomalous waves， which enhance the key circulation systems in the north and south affecting the cold wave frequency in the southern China.When the North Atlantic SSTA exhibits an inverse "C" anomaly in spring， and there is a trend of developing into a “+”“-”“+” tripolar pattern in summer and autumn， the winter cold wave frequency in the southern China can be predicted to more.