夏季强沙尘暴内部热力动力特征的个例研究  

Case Study of Dynamical and Thermo-dynamical Structure of Serve Dust-storm in Summer

作　　者：岳平[1] 牛生杰[2] 张强[1] 沈建国[3] 

机构地区：[1]中国气象局兰州干旱气象研究所/甘肃省干旱气候变化与减灾重点实验室/中国气象局干旱气候变化与减灾重点开放实验室 [2]南京信息工程大学气象灾害国家重点实验室培育点,江苏南京210044 [3]内蒙古自治区气象局,内蒙古呼和浩特010051

出　　处：《中国沙漠》2008年第3期509-513,599,共6页Journal of Desert Research

基　　金：国家自然科学基金项目(4070500540765001);教育部博士点基金(20050300002);科技部公益专项(2005DIB3J108)共同资助

摘　　要：根据对流体在热低压条件下激发强沙尘暴的机理,并应用Rennó和Ingersoll于1996年提出的热机自然对流理论,对2004年7月12日甘肃省酒泉基准站发生的强沙尘暴内部动力热力结构进行了探讨。结果表明:①在沙尘暴发生前的一小时大气底层处于干热状态,垂直方向巨大的温度梯度有利于干对流发展。②激发强沙尘暴的对流体的切向旋转速度和垂直运动速度的大小,很大程度上决定了沙尘暴的强弱。③利用酒泉站探空资料计算出的沙尘暴对流体的最大切向旋转速度为11.4m.s-1,垂直运动速度为14.0m.s-1;地面沙尘暴观测系统记录的平均环境风速仅为5.5m.s-1,瞬间最大风速只9.3m.s-1。According to the formation mechanism of dust-storm stimulated by serve convection system under hot-low,the thermodynamical structure of a dust-storm which occurred in the Jiuquan area of Gansu Province at 20:00 on July 12,2004 was analyzed based on the theory of hot-engine natural convection proposed by Renn and Ingersoll in 1996.Findings are as follows: ①The atmospheric bottom layer was dry and heat in an hour before dust-storm occurrence,and there was extreme temperature grade between 200 hPa and 300 hPa,which was advantageous to the development of dry convection.②The intensity of the dust-storm was closely related to the tangential and vertical velocity of micro-scale and meso-scale convections.Being computed by the sounding data from Jiuquan station the tangential velocity of dust-storm was 114 m·s-1 and the vertical velocity was 14 m·s-1;the maximal surrounding velocity recorded by the surface dust-storm observational system was only 93 m·s-1,and the average was 55 m·s-1.

关 键 词：沙尘暴 动力热力结构 自然对流 切向速度 垂直速度 

分 类 号：P445.4[天文地球—大气科学及气象学]