| “4·23”南疆翻山型强沙尘暴动力结构特征分析 |
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| 引用本文： | 李娜,闵月,汤浩,刘雯.“4·23”南疆翻山型强沙尘暴动力结构特征分析[J].冰川冻土,2017,39(4). |
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| 作者姓名： | 李娜 闵月 汤浩 刘雯 |
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| 作者单位： | 1. 新疆维吾尔自治区气象台,新疆乌鲁木齐,830002;2. 中国气象局乌鲁木齐沙漠气象研究所,新疆乌鲁木齐830002;中亚大气科学研究中心,新疆乌鲁木齐830002 |
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| 基金项目： | 中国沙漠气象科学研究基金项目,新疆维吾尔自治区科技支撑项目,新疆气象局科学技术研究与应用技术开发项目 |
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| 摘 要： | 利用2014年4月22日-23日高空、地面、区域自动气象站加密观测和1°×1°NCEP/NCAR再分析资料,分析4月23日南疆翻山型强沙尘暴天气的高低空环流及动力结构特征。结果表明:巴尔喀什湖低槽引导极地干冷空气爆发性南下进入南疆,造成4×10-2h Pa·km-1剧烈的气压梯度和地面冷锋,引发了大风、强沙尘暴,盆地中尺度低压辐合使尉犁加强为"黑风";300 h Pa极锋急流快速南下至南疆盆地,动量下传形成低空急流,高低空急流是此次强沙尘暴形成的动力条件;急流附近高空辐散、低层辐合及层结不稳定,有利于沙尘暴发生。本次强沙尘暴动力结构特征:干冷与干暖空气剧烈交绥,激发热力不稳定,产生热力对流;高空辐散、低层辐合与高低空急流、地面冷锋配合,加强上升运动,使地面沙尘卷入空中并输送;高低空急流抽吸加强冷暖空气垂直运动,位能向动能转化,引起了地面大风,驱动沙尘暴发生。
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| 关 键 词： | 翻山型强沙尘暴 高低空环流 中尺度低压 高低空急流 动力结构 |
Analyzing the dynamic structural characteristics of the severe sandstorm caused by cold air crossing mountains in Southern Xinjiang on April 23rd, 2014 |
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| LI Na,MIN Yue,TANG Hao,LIU Wen.Analyzing the dynamic structural characteristics of the severe sandstorm caused by cold air crossing mountains in Southern Xinjiang on April 23rd, 2014[J].Journal of Glaciology and Geocryology,2017,39(4). |
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| Authors: | LI Na MIN Yue TANG Hao LIU Wen |
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| Abstract: | The upper-lower tropospheric circulation and dynamical structural characteristics of a strong sand-dust storm which occurred over southern Xinjiang on 23rd April,2014 was investigated by using NCEP/NCAR reanalysis data (horizontal resolution 1 ° × 1 °) and the 23rd ～ 24th April field data from automatic meteorological station.The results are as follows:Affected by Balkhash Lake trough,the polar cold and dry air spread southwards and reached Tarim basin,resulting in strong pressure gradient of 40 hPa (1000kin)-1 and surface cold front,further inducing strong wind and sand storms.Besides,the surface convergence of low pressure system upon the Tarim basin also contributed to the formation of "black storm" in Yuli region.(2) 300 hPa Polar Front Jetstream (PFJ) intruded southwards into the Tarim basin,further generated low-level Jet (LLJ) through the downward momentum transportation mechanism.PFJ and LLJ provided the dynamical conditions for the formation of sand storm.Near the Jetstream,all the upper atmospheric divergence,lower atmospheric convergence and stratification instability benefited the sandstorm.(3) Several dynamical characteristics of this strong sandstorm made it different from other sandstorms.First of all,severe dry-cold air and dry-warm air convergence stimulated thermal instability and induced heat convection.Secondly,upper atmospheric divergence,lower atmospheric convergence,Jet stream,LLJ and surface cold front worked together to strengthen the upward motion of lower atmosphere,so that the dust was involved into the air and transported.Most of all,Jet stream and LLJ together promoted the cold air and warm air vertical movement,the conversion from potential energy to kinetic energy generated the surface winds,which finally triggered the dust storms. |
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| Keywords: | sandstorm caused by cold air crossing mountains high and low air circulations mesoscale low pressure upper-level and low-level jet stream dynamic structure |
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