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中国沙漠 ›› 2012, Vol. 32 ›› Issue (4): 1127-1134.

• 天气与气候 • 上一篇    下一篇

一次强天气过程天山地形方案的敏感性试验研究

马玉芬, 赵 玲, 赵 勇   

  1. 中国气象局乌鲁木齐沙漠气象研究所, 新疆 乌鲁木齐 830002
  • 收稿日期:2011-10-23 修回日期:2012-02-08 出版日期:2012-07-20 发布日期:2012-02-08

A Sensitive Experiment of Impact of Tianshan Mountains Landform on a Rainstorm Process

MA Yu-fen, ZHAO Ling, ZHAO Yong   

  1. Institute of Desert Meteorology, China Meteorological Administration, Urumqi 830002, China
  • Received:2011-10-23 Revised:2012-02-08 Online:2012-07-20 Published:2012-02-08

摘要: 为定量研究天山山脉地形对新疆强降水天气的影响作用,用WRFV3.1模式对2009年5月24日夜间至26日夜间新疆地区自西向东出现的降水、大风、降温天气过程进行了数值模拟,并通过改变天山山脉的地形高度设计了一组敏感性试验。结果表明:①天山山脉的地形作用是此次强降水天气过程在天山山区形成暴雨的主要原因之一;随着地形的升高,降水分布更不对称,更不均匀,雨带在天山迎风坡一侧的带状分布特征越明显,迎风坡一侧的降水量极值越大;地形的抬升作用对暴雨在山脉迎风坡一侧的降雨量有明显的增幅作用,对其雨带分布也有显著影响\.②天山山脉对这次强降水天气过程中的西南暖湿气流有明显的分流与阻挡作用;天山山脉将西南暖湿气流分为南北两支,使北支的水汽混合比极大值减小,湿区范围增大;使南支的水汽混合比极大值增大,湿区范围增大。③天山山脉的地形抬升作用为“5·25”强降水过程在天山山区发生暴雨天气创造了水汽的垂直上升运动条件,对昆仑山北坡暖湿气流的垂直上升运动也有一定的贡献作用。④天山山脉地形对准噶尔盆地西北部直至天山山脉北侧的气流有明显的阻挡与减缓作用,对三十里风区、百里风区、汗腾格里峰北坡强风带的形成有直接而重要的作用;地形高度越高,产生垂直运动的地形抬升机制越强,地形强迫抬升作用产生的垂直上升运动越剧烈\.⑤天山山脉明显地减轻了寒潮天气过程中南疆塔里木盆地的降温幅度,对准噶尔盆地北部的寒潮降温幅度也有一定的减缓作用,对塔里木盆地的“保温”作用较准噶尔盆地明显。

关键词: 数值模拟, 敏感性试验, 地形, 暴雨, 大风, 降温

Abstract: For quantitatively studying the effect of the Tianshan Mountains landform on regional rainstorm, a simulation experiment with WRFV3.1 model on a rainstorm process accompanied by gale and cold wave occurred at the night of 24th and lasted till the night of 26th of May, 2009 in Xinjiang was conducted. A set of sensitive experiments were designed through changing the topographic height of the Tianshan Mountains. Some conclusions are drawn as follows: (1) The topographic effect of the Tianshan Mountains is one of the dominating causes of rainstorm occurring in the Tianshan Mountains. The higher the terrain of the Tianshan Mountains is, the more uneven of the rainfall distribution, and the more outstanding of the zonal distribution of the precipitation on the windward slope, also the lager the maximum precipitation on the windward slope. The topographical effect is significant in increasing the rainfall volume on the windward slope, which also plays a great role in the distribution of rainfall region. (2) The Tianshan Mountains not only obstructs the northeastward moving of the warm and wet flows from the southwest, but also divides this air stream into two parts and further makes the north part become weaker and wider while made the south part stronger and wider. (3) Topographic blocking of the Tianshan Mountains contributes to the upward movement of warm and wet airflows over the Tianshan Mountains, which creates the vertical flow ascending condition during a rainfall process; and it also contributes to the upward movement of warm and wet airflows over the north slope of the Kunlun Mountains to some extent. (4) The Tianshan Mountains plays a great role not only in obstructing and retarding the air stream from the northwest part of the Junggar Basin to the north slope of the Tianshan Mountains, but also in formation of the notable gale fields along the Lanzhou-Xinjiang railway, namely "Sanshili wind field" and "Baili wind field", as well as the gale belt in the north slope of Khan Tengri Peak. The higher the topographic height is, the stronger the forcing uplifting function and the more fierce vertical rising movement. (5) The Tianshan Mountains can significantly alleviate the extent of air cooling in the Tarim Basin and the Junggar Basin, while that in the former is much more obvious than that in the latter.

Key words: numerical simulation, sensitive experiment, landform, rainstorm, gale, air cooling

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