2015/2016年初冬大连地区2次低温过程特征分析  

Diagnostic Analysis of Two Low-temperature Processes in Dalian in Early Winter of 2015 and 2016

作　　者：梁军 黄艇 张胜军[2] 李雪松 

机构地区：[1]辽宁省大连市气象台,辽宁大连116001 [2]中国气象科学研究院灾害天气国家重点实验室,北京100081

出　　处：《干旱气象》2017年第1期73-81,共9页Journal of Arid Meteorology

基　　金：环渤海区域科技协同创新基金项目(QYXM201501);大连市科技计划项目(2014E21SF009)共同资助

摘　　要：2015/2016年11月下旬大连地区出现2次低温过程。降温期间,2016年大连上空对流层中下层温度明显低于2015年,但2015年地面最低气温为1971年以来历史同期最低值。利用GTS1型数字式探空仪、常规气象观测资料及NCEP/NCAR再分析资料,对大连地区2015、2016年初冬的2次低温过程(2015年11月24日和2016年11月22日)进行对比分析,研究低温发生的环流背景及温度场、锋区结构、冷空气路径等特征。结果表明,降温期间大连均位于高空槽前。2015年11月24日的低温发生在乌拉尔山东侧高压脊发展、维持阶段,低层冷空气从吉林东南部地区自上而下楔形快速向西南侵入,大连地区锋生作用加强,逆温层增厚,逆温梯度增大,加剧了其地面温度的下降,市区最低气温突破历史同期极值。2016年11月22日的低温则发生在乌拉尔山东侧高压脊减弱、崩溃阶段,对流层整层冷空气从华北西北部向东南偏南方向爆发,大连地区锋生作用偏弱,逆温层变薄,逆温梯度减小,其地面温度的下降幅度明显偏小。冷空气所经下垫面不同,降温幅度不同。东北地区回流冷空气的直接影响容易导致大连地区的极端低温。Two low temperature processes during the third dekad in November 2015 and 2016 occurred in Dalian which gave rise to serious temperature drops. During cold air invasion, the temperature at lower - layer in November 2016 was lower than that in November 2015 over Dalian, but the minimum surface air temperature for the later was - 10. 5 , which was the coldest at same time since1971. By using the NCEP/NCAR reanalysis data, conventional observations and the sounding data from GTS1 digital radiosonde in Dalian, comparative analysis were made about characteristics of the large scale circulation, the temperature field, frontal structure and the cold air, s track associated with the two low - temperature processes in Dalian from 23 to 24 Nov 2015 and from 21 to 22 Nov 2016. The results show that the large scale circulations of two low - temperature processes were different. For the first process, the blocking ridge over the east of the Urals was building and developing, and Dalian was located in front of 500 hPa trough. In the lower tropo-sphere, the cold air from the southeast of Jilin Province outbroke towards the southwest and intruded into Dalian. High - level warm air-flow and cold airflow in lower troposphere would be benefit for the formation of the inversion layer at lower - layer. Meanwhile, cold air-flow at high latitude moved rapidly toward Dalian. Interaction between warm air and cold air was prone to formation of se frontal zone. Low - temperature over Dalian appeared in the frontogenesis of cold front in the lower layer. When surface temperature decreased, the thickness of inversion layer was thicker, its gradient was larger. Minimum temperature in Dalian was the lowest during the third dekad in November. For the second one, Dalian was also located in front of 500 hPa trough, but the blocking ridge over the east of the Urals was weakening and collapsing. The cold air from the northwest of north China moved towards the southeast and cold cores from lower to upper level were located in the north

关 键 词：低温 阻塞脊 逆温层 对比 

分 类 号：P458.1[天文地球—大气科学及气象学]