| 摘要: |
| 利用非静力平衡的中尺度模式(MM5)对1994年5月初华南地区的暴雨过程进行模拟和分析,结果表明:(1)MM5相当准确地模拟出此次暴雨过程以及有关的中尺度系统的发生发展过程。(2)在弱的天气尺度背景条件下,边界层的中尺度辐合对暴雨的产生起了触发作用。暴雨强度一般随对流层上下部的辐散差值的增大而增大,最大的降水强度对最大的辐散差值的滞后时间不超过一小时。(3)降水的潜热加热作用对此次暖区暴雨的发展和维持有决定性的作用。凝结加热引起的次级环流使暴雨区附近的中尺度急流和切变线扰动得到发展和维持,从而使辐合上升和降水得以进一步加强,它们之间的相互作用过程与CISK机制相似。 |
| 关键词: 暴雨 数值模拟 低空急流 行星边界层 凝结加热 |
| DOI： |
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| 基金项目:国家攀登A项目(南海季风试验研究);广东省科技攻关项目(广东暴雨监测与预报技术研究)资助 |
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| A MODELING CASE STUDY OF HEAVY RAIN EVENT OVER SOUTH CHINA IN MAY L994 |
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GU Zhi-ming1, FONG Soi-kun1, WU Chi-sheng2, WANG An-yu2, LIN Wen-shi2, YANG Yan2
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1.Geophysical and Meteorological Observatory Macao, Macao, China;2.Departure of Atmospheric Science, Zhongshan University
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| Abstract: |
| This paper presents results of simulations for a case of heavy rain that occurred in May 1994 over South China using the fifth generation Penn State/NCAR mesoscale model (MM5). The model result recaptures the major observed features of these events as well as the associated mesoscale system. Within a weakly fored synotic scale environment, convective activity was trigged by boundary layer convergence.The hourly precipitation generally increased with the increasing of magnitude of 200 hPa divergence minus 925 hPa convergence,and the occurring time of maximum precipitation rate lagged that of the maximum divergence difference by less than an hour.The secondary circulation induced by latent heat release resulted in the development and maintaining of mesoscale low-level jet and disturebance,then the mesoscale rising motion and precipitation as well as latent heat release were further strengthened.This reaction process is simily to .CISK Therefore the latent heating is a crucial factor in the development and maintaining of this heavy raill process. |
| Key words: precipitation numerical simulation low-level Jet planetary boundary layer latent heat release |
