| 2018年盛夏大连地区极端高温干旱天气环流特征及成因分析 |
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| 引用本文： | 王秀萍,李燕,张悦,赛瀚,李潇潇.2018年盛夏大连地区极端高温干旱天气环流特征及成因分析[J].气象与环境学报,2021,37(4):70-77. |
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| 作者姓名： | 王秀萍 李燕 张悦 赛瀚 李潇潇 |
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| 作者单位： | 1. 大连市气象台, 辽宁 大连 1160012. 大连市气象信息中心, 辽宁 大连 116001 |
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| 基金项目： | 中国气象局沈阳大气环境研究所联合开放基金课题(2021SYIAEKFMS04);2020年辽宁省市县级气象局自筹资金科研课题(2020SXG03);大连市气象局业务应用开发项目(dlqk201908) |
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| 摘 要： | 利用1951-2018年大连地区7个站的逐日气温和降水资料、2018年7-8月220个自动站的降水资料及1948-2018年NCEP逐日再分析资料，对2018年盛夏大连地区极端高温干旱天气过程的基本特征及大气环流异常成因进行分析。结果表明：大连地区各站的高温日数和高温持续日数均列历史首位，持续无降水日数远超历史同期纪录，降水较常年偏少7-8成。大连地区上空受正压结构的异常反气旋性环流控制，并叠加欧亚(EU)遥相关型，同时，东亚沿岸由南至北为"负-正-负"的高度距平分布，呈"东亚-太平洋型"遥相关负位相的特征，对流层低层菲律宾附近至日本以南地区维持异常的气旋式环流。西太平洋副热带高压异常偏西偏北，与异常偏东偏北的南亚高压相向运动，强度同步发展加强并叠加在大连地区上空，引起整层大气增温。高空西风急流异常偏北，冷空气活动偏北不易南下。在副热带和东亚中高纬大气环流的这种配置下，大连地区上空受异常反气旋控制，在其南侧存在一个气旋性环流，阻挡暖湿气流向大连地区输送，加之异常辐散下沉运动影响，不利于形成降水。
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| 关 键 词： | 高温干旱 欧亚EU波列 大气环流异常 |
| 收稿时间： | 2020-05-10 |
Analysis of circulation characteristics and cause of extremely high temperature and drought in midsummer of 2018 over Dalian area |
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| Xiu-ping WANG,Yan LI,Yue ZHANG,Han SAI,Xiao-xiao LI.Analysis of circulation characteristics and cause of extremely high temperature and drought in midsummer of 2018 over Dalian area[J].Journal of Meteorology and Environment,2021,37(4):70-77. |
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| Authors: | Xiu-ping WANG Yan LI Yue ZHANG Han SAI Xiao-xiao LI |
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| Institution: | 1. Dalian Meteorological Observatory, Dalian 116001, China2. Dalian Meteorological Information Center, Dalian 116001, China |
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| Abstract: | Based on temperature and precipitation data of seven meteorological stations from 1951 to 2018 in the Dalian area, the daily precipitation data of the 220 automatic stations during July and August of 2018, the NCEP/NCAR (National Centers for Environmental Prediction-the National Center for Atmospheric Research Reanalysis) daily mean reanalysis data during 1948-2018, the features of the persistent and serious high temperature and drought from July 1 to August 31 of 2018 in Dalian and its causes of atmospheric circulation anomalies were analyzed. The results show that it records a breaking extreme value of the number of long persistent high-temperature days and no-precipitation days in the midsummer of 2018 in the Dalian area. The rainfall is at least 70%-80% lower than the historical average. The Dalian area is controlled by an unusual anticyclone from the lower troposphere to the upper troposphere and jointed the teleconnection pattern over the Eurasia continent (EU pattern). At the same time, the pattern of "-+-" of 500 hPa geopotential height anomaly along the East Asian coast from south to north, which means to show a negative East Asia Pacific teleconnection pattern, a cyclonic circulation of wind anomalies at 850 hPa dominates around the south of Japan and Philippines. The abnormally westward and northward Western Pacific Subtropical high exist a tendency to move in opposite directions and the South Asian high, which is abnormally eastward and northward, their intensity enhance at the same time and overlap over the Dalian area, which causes atmospheric warming of the entire troposphere. Meanwhile, the East Asian subtropical westerly jet lies significantly northward compared with the average situations, so it is not favorable for the cold air moving southwards. Under the combined impacts of the subtropical and mid-high latitude atmospheric circulation over Eurasia, the Dalian region is affected by an abnormal anticyclone. The anomalous cyclonic circulation on the southern side of the anomalous anticyclonic circulation blocks the warm and humid airflow to Dalian, and its anomalous airflow divergence area of water vapor flux occurs in the region, combined with the descending motion effects, which result less precipitation. All the key reasons bring about the anomalous high-temperature and drought weather in Midsummer of 2018 over the Dalian area. |
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| Keywords: | High temperature and drought EU pattern Atmospheric circulation anomaly |
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