中国北方暴雪的年代际变化及其大气环流和北极海冰异常变化的联系
投稿时间:2018-12-12  修订日期:2018-12-18  点此下载全文
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作者单位E-mail
陈海山 南京信息工程大学 大气科学学院 haishan@nuist.edu.cn 
罗江珊 南京信息工程大学 大气科学学院  
韩方红 南京信息工程大学 大气科学学院  
基金项目:国家重点研发计划重点专项资助项目(2016YFA0600702)
中文摘要:采用相关、回归等统计方法对中国北方暴雪在年代际尺度上的变化特征及其与大气环流和北极海冰的联系进行了探讨。结果表明:我国北方冬季暴雪发生频次较高的主要位于东北,在空间分布表现为从西北到东南增加的态势,且存在明显的年代际变化:1965?1980年为东北暴雪少发期; 2002?2011年则为东北暴雪多发期。进一步分析发现暴雪少发期,向东北输送的水汽较少;但在2002?2011阶段,更多的水汽输送来自于西北太平洋,同时,偏北气流引导的极地冷空气与偏南风引导的太平洋暖湿水汽在东北地区汇合锋生,提供暴雪频发的动力条件,造成东北暴雪出现年代际增多。此外,研究发现前期秋季北极海冰的年代际减少与东北暴雪的年代际增加存在很好的相关性。秋季北极海冰异常偏少导致的大气环流异常主要表现为纬向西风的减弱和NAO负位相,导致经向活动增强,有利于极地冷空气向南入侵,冷空气与暖湿水汽在东北地区汇合,东北暴雪年代际增加的一个可能重要原因。
中文关键词:中国北方暴雪 年代际变化 大气环流 北极海冰
 
Interdecadal Variation of Winter Heavy Snowfall in North China and possible Linkages with Anomalous Atmospheric Circulation and Arctic Sea Ice
Abstract:Based on statistical analysis, the interdecadal variation of the heavy snow in Northern China and the relationship with anomalous atmospheric circulation and Arctic sea ice are explored in this study. Results show that the high frequency of wintertime heavy snow is mainly located in Northeast China (NEC), and its spatial distribution shows an increasing trend from the northwest to the southeast, together with an evident interdecadal variation. Heavy snowfall in NEC is less frequent during the period of 1965?1980, but becomes more frequent during the period of 2002?2011. Further analysis found that there is less water vapor transported to the NEC during the period of 1965?1980, but more water vapor transported from the Northwest Pacific Ocean to the NEC during the period of 2002?2011. Meanwhile, the intensified polar cold air activity and stronger warm moisture transport from the north-west Pacific benefits the convergence frontogenesis in NEC, providing favorable dynamic conditions for the frequent occurrence of wintertime heavy snow, and leading to the interdecadal increase of heavy snow in NEC. Furthermore, it is found that there is a close linkage between the interdecadal decrease of Arctic sea ice and the interdecadal increase of snowstorm in NEC. The significantly decreased zonal westerly and anomalous circulation pattern similar to the NAO-negative phase caused by the decreased Arctic sea ice, can intensify the atmospheric meridional activity and the convergences of cold air and warm moist, resulting in the decadal increase of the wintertime heavy snow in the NEC.
keywords:Heavy snow in Northern China, Interdecadal Variation, Atmospheric Circulation, Arctic Sea Ice
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