【摘要】 利用1979~2011年中国东北地区119站气温观测数据,对东北春季寒潮的年代际变化特征进行了分析,并在此基础上通过分析大气环流及北极海冰的变化,对寒潮年代际变化的可能原因进行了探讨。结果表明,东北地区春季寒潮的频次及强度在20世纪80年代末和21世纪初均有明显年代际转折,即20世纪90年代寒潮频次减少而强度增加,21世纪初寒潮频次有所回升但强度减弱。北极新地岛地区海冰的变化可能是造成我国东北地区寒潮活动年代际变化的原因之一。20世纪90年代新地岛附近海冰迅速减少,地表温度明显升高,而高纬海平面气压偏低,此处冷空气不易南下,同时东亚大槽偏强,冷空气强度增加。21世纪初该区海冰减少趋势减缓,冷空气频次有所回升,强度减弱。更多还原

【Abstract】 Based on 1979-2011 daily surface temperature data collected at 119 stations in Northeast China, the decadal variability of cold waves across Northeast China was investigated. The possible causes for the decadal changes were also discussed through analyzing changes in atmospheric circulation and Arctic sea ice. The frequency and intensity of spring cold waves across Northeast China both changed at the end of the 1980 s and in the early 2000 s. Cold waves in the 1990 s were less frequent but stronger than those in the 1980 s, and less frequent but weaker than those in the 2000 s. The change in sea ice concentration around Novaya Zemlya was a possible cause for the decadal variability of spring cold waves in Northeast China. Rapid decrease in sea ice in Novaya Zemlya significantly increased surface air temperature(SAT) and weakened sea level pressure(SLP) in the high latitudes around this region, which were not favorable for the southward movement of cold air over Novaya Zemlya. In addition, the decrease in sea ice cover around this area and the deep East Asia trough could also lead to the strengthening of cold waves across Northeast China, while the cold waves in the 2000 s became weaker but occurred more frequently possibly due to a slower decrease trend of sea ice cover in Novaya Zemlya.更多还原