Title

凝結加熱和地表通量對華南中尺度對流系統(MCS)發生發展的影響

Translated Titles

Effects of Condensation Heating and Surface Fluxes on the Development of a South China Mesoscale Convective System (MCS)

Authors

蒙偉光(Wei-Guang Meng);李江南(Jiang-Nan Li);王安宇(An-Yu Wang);馮瑞權(Soi-Kun Fong);古志明(Chi-Meng Ku);閆敬華(Jing-Hya Yan)

Key Words

凝結加熱 ; 地表通量 ; 中尺度對流系統MCS ; 華南暴雨 ; 數值模擬 ; condensation heating ; surface fluxes ; mesoscale convective system MCS ; South China heavy rainfall ; numerical simulation

PublicationName

熱帶氣象學報

Volume or Term/Year and Month of Publication

21卷4期(2005 / 08 / 01)

Page #

368 - 376

Content Language

簡體中文

Chinese Abstract

通過有無凝結加熱和地表通量影響的數值模擬對比研究,分析了非絕熱過程對一次華南暴雨MCS發生發展過程的影響。結果表明:(l)凝結加熱對MCS的降水影響很大,在MCS發展的各個時期,如不考慮凝結加熱,MCS的降水強度很快減弱,無法繼續發展。(2)凝結加熱在MCS渦旋的形成期最為重要,在渦旋形成之後,影響相對減弱。(3)凝結加熱通過對MCS發展過程的影響從而也影響了MCS環境場中尺度低空急流、高層輻散等中尺度結構特徵的形成。(4)地表感熱、潛熱通量等邊界層非絕熱過程對MCS的形成也有重要影響;在暴雨MCS發生前期,地表非絕熱過程造成氣壓下降,導致華南南部來自海洋的偏南風加大,輻合加強,從而使低層的濕度增大,氣層變得更加不穩定,有利於對流的啟動。

English Abstract

A sensitive numerical simulation study is carried out to investigate the effects of condensation heating and surface fluxes on the development of a South China MCS that occurred during 23~24 May 1998. Results reveal that: (1) Condensation heating plays an important role in the development of MCS. In every different stage, without condensation heating, MCS precipitation is significantly reduced, and quickly dissipates; (2) Condensation heating demonstrates most importantly during the early development stages of MCS vortex, as the vortex develops stronger, the condensation heating effects reduces; (3) By affecting the MCS development processes, condensation heating also influences the formation of MCS mesoscale environment structure features such as low-level jet (mLLJ), upper-level divergence; (4) By changing the antecedent environmental circulation, the surface fluxes also play an important role in the development of MCS. Because of the surface heating, pressure declines over the heavy rainfall and MCS happening regions, which results in the intensification of southerly flows from the ocean along the South China coastline areas, and leads to the enhancement of horizontal convergence and increase of vapor amount in the lower layer. All these make the atmosphere becoming more unstable and more favorable for the convection.

Topic Category 基礎與應用科學 > 大氣科學