中国东部北方地区冬季降雪的时空特征及其与全球异常海温的联系

The Spatial and Temporal Characteristics of Winter Snowfall in Northeast China and Its Relation with Global Sea Surface Temperature Anomaly

基于中国东部北方地区279个气象台站1961—2008年的观测资料,以及1°×1°的全球海表温度资料,运用主成分分析、小波分析、相关分析等方法探讨中国东部北方地区冬季降雪的时空特征及同期全球海温与其的相关性。研究发现:中国东部北方区域(以下简称研究区)冬季降雪量存在2～3 a、7～8 a的高频振荡周期,及一个准16 a的年代际尺度的低频振荡周期。在1961—2008年间,研究区域冬季降雪量总体呈现上升趋势,特别是45°N以北的研究区北部区域冬季降雪量在48年间增加显著,而45°N以南的研究区南部区域冬季降雪量变化并不明显。分析发现,位于北大西洋上30°～50°N,10°～40°W海区的海温与研究区域降雪的第一、二特征向量均为显著的正相关,研究区北部冬季降雪量与海温关系密切,南部区域冬季降雪量与全球海温的相关性不明显,海温变暖可能是导致研究区北部降雪显著增加的重要因素。

Based on the observational data in the period 1961-2008 from China weather stations and the 1°× 1°global sea surface temperature （SST） data, the spatial and temporal characteristics of winter snowfallin Northeast China and the correlation with global SST are explored by using principal component analysis,wavelet analysis and correlation analysis. The study found that： the high frequency oscillation periods （2-3 a and 7-8 a） and a quasi-decadal scale （16 a） of the low-frequency oscillation were always existing dur-ing the past 48 years. Winter snowfall revealed an increasing trend in the past 48 years as a whole in Northeast region. However, the winter snowfall in the area north of 45°N increased significantly, while itdid not change significantly in the area south of 45°N. Analysis has shown that a significantly positive cor- relation exists between SST in the North Atlantic 30°-50°N, 10°-40°W and the lst/2nd time coefficient,and also between the winter snowfall in the northern part of the study area and SST, but the correlationbetween winter snowfall in the south region and the global SST is not obvious. The warming of SST maylead to a significant increase in snowfall in the northern part of the study area.