引发2011年8月宁夏持续高温天气的青藏高压结构分析  

Analysis on Structure of Tibetan High in the Consecutive High Temperature Weather in Ningxia in August 2011

作　　者：陈豫英[1,2] 陈楠[1,2] 穆建华[1] 朱海斌 何佳 

机构地区：[1]宁夏气象防灾减灾重点实验室,银川750002 [2]宁夏气象台,银川750002 [3]宁夏石嘴山市气象台,石嘴山753000

出　　处：《气象》2013年第8期988-994,共7页Meteorological Monthly

基　　金：宁夏科技支撑计划项目(2012ZYS160);宁夏自然基金项目(NZ12280);宁夏气象防灾减灾重点实验室开放研究基金项目"宁夏高影响天气精细化预报关键技术研究"共同资助

摘　　要：利用常规气象观测资料、中尺度区域自动站逐时地面资料及NCEP／NCAR1°×1°再分析资料等，对引发2011年8月6—10日宁夏中北部连续5天出现≥35℃的高温天气的青藏高压水平和垂直结构进行了天气学分析。结果表明：青藏高压是一个深厚的暖性负涡度系统，它与西风带长波脊的同位相叠加使得高原上空的长波脊和暖高压稳定加强，受其影响，青藏高压外围586dagpm线东移越过高原后稳定维持在85°～105°E附近，高压脊线北界伸展到40°～42°N，西北地区大范围长时间处在584dagpm以上的青藏高压和1000hPa以下的地面热低压控制区域内；高压上空在中纬度极锋急流的作用下，高原东部存在“高空辐合、低空辐散”的环流配置导致高原东部维持较强的下沉运动，处在下沉区的宁夏上空晴朗少云，湿度小，风力相对较大，地面增温和蒸发强烈，地面感热远远大于潜热，有利于出现以“干热”为主的持续高温天气。在此基础上，文章提出了宁夏夏季高温的概念模型。A high temperature weather process occurred in central and northern part of Ningxia from Au- gust 6 to 10 in 2011. Using conventional observation data, hourly ground observation data of mesoscale re- gional automatical weather stations and NCEP/NCAR 1°×1° reanalysis data, this paper analyzes the hori- zontal and vertical structure of the Tibetan high which has close relationship with the high temperature weather process. The results show that： Tibetan high is a thick warm negative vorticity system, whose in- phase-superpostion with the westerly long wave high pressure ridge strengthens the long wave high pres- sure ridge and warm high pressure over Tibetan plateau. The 586 dagpm line of the periphery of Tibetan high passes over Tibetan Plateau and maintains steadily near 85°- 105°E, and the north boundary of Tibet- an high extends to 40°--42°N. Most parts of Northwest China are under the control of Tibetan high over 584 dagpm and surface thermal low under 1000 hPa for a very long time. Polar front jet and upper level jet interact over Tibetan high, and the circulation converging in upper level and diverging in low level results in strong sinking motion over eastern Tibetan Plateau. It was cloudless in Ningxia where is located in that sinking motion region with low humidity, relatively high wind speed, strong warming and evaporating at ground and the surface sensible heat was much higher than latent heat. All these factors are benefitial for the occurrence of consistent high temperature weather. Finally, this paper proposes a conceptual model for summer high temperature weather in Ningxia.

关 键 词：高温天气 青藏高压 水平和垂直结构 概念模型 

分 类 号：P441[天文地球—大气科学及气象学]