冬季欧亚积雪异常对北太平洋风暴轴的影响

通过对23个冬季,欧亚积雪与北太平洋风暴轴区域500 hPa天气尺度滤波位势高度方差进行奇异值分解(SVD)、相关分析和合成分析,研究了冬季欧亚积雪异常对北太平洋风暴轴的影响.结果表明,冬季欧亚积雪面积正异常时,北太平洋风暴轴主体位置南压,并且中心强度减弱;积雪面积负异常时,结果相反.进一步的分析显示,欧亚雪盖面积异常所导致的冷却效应异常通过改变欧亚大陆及其下游北太平洋上空的高度场,进而改变东亚急流和斜压性,从而对北太平洋风暴轴产生影响.

Effects of Eurasian Snow Cover Anomaly on Northern Pacific Storm Track during Winter

Effects of Eurasian snow cover anomaly on storm track is studied in this paper by the singular value decomposition(SVD),correlation analysis and composite analysis of the 23 winters' 500 hPa filtered potential height variance over the north Pacific storm track region and the Eurasian snow cover data.And the possible influencing mechanism is also discussed.It is shown that the positive Eurasian snow-cover's area anomaly leads to the southward shift and weakening of Pacific storm track,and vice versa.Deep investigation shows that the anomalous cooling of Eurasian snow cover gives rise to changes in the upper lever geopotential heights over the Eurasian continent and its downstream Pacific ocean,then the East Asia jet steam and baroclinicity,and finally the storm tracks.