| 摘要: |
| 本文利用加密自动站雨量、实况观测资料、FY-2G卫星TBB以及NCEP/FNL每日4次的1°×1°全球再分析资料,来对2018年6月19日湖南的中部喇叭口地形处的一次极端强降水天气过程成因进行详细分析。结果表明：(1)此次极端强降水是在大气环流形势稳定、弱的天气尺度背景下发生的；(2)不同地形影响下同等强度的对流云团在量级上存在显著差异,异常强的短时强降水出现喇叭口地形附近或迎风坡处。(3)低层浅薄的偏东风的渗入和中小尺度地形的阻挡和强迫抬升作用,是极端强降水区域出现异常旺盛的上升运动的主要原因； (4)中层偏东风携带干冷空气侵入近地面发展旺盛的暖倒槽内,是此次强对流天气的发生的主要触发机制。地面浅薄的东风气流的长时间维持、南侧偏南气流的加强及地形的阻挡作用有利于地形峡口处的中尺度切变线的长时间维持是强降水持续的主要原因。 |
| 关键词: 极端强降水; 弱天气尺度; 偏东风; 中小尺度地形 |
| DOI： |
| 投稿时间：2019-01-16修订日期：2019-03-29 |
| 基金项目: |
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| Analysis of the Influence of the Interaction between the East Wind and the Terrain on the Extremely Heavy Rainfall in Hunan Province |
| changliwei,jiaanbin,Huangzhuoyu |
| (Yueyang Meteorological Bureau;Changde Meteorological Bureau;Loudi Meteorological Bureau) |
| Abstract: |
| Abstract: This paper uses the encrypted automatic station rainfall, live observation data, FY-2G satellite TBB and NCEP/FNL 4 times daily 1 ° × 1 ° global reanalysis data to the central bell of Hunan on June 19, 2018. A detailed analysis of the causes of an extremely severe precipitation event at the topography. The results show that: (1) The extreme precipitation occurs in the background of stable and weak weather conditions; (2) The convective clouds of the same intensity under different terrains have significant differences in magnitude, and are extremely strong. The short-term heavy precipitation appears near the flared terrain or on the windward slope. (3) The infiltration of low-level shallow easterly winds and the blocking and forced uplift of small- and medium-scale terrain are the main reasons for the unusually strong ascending motion in extremely heavy precipitation areas; (4) The mid-easterly easterly wind carries dry and cold air into the ground and develops vigorously. The warming down tank is the main trigger mechanism for the occurrence of this strong convective weather. The long-term maintenance of the shallow Dongfeng airflow on the ground, the strengthening of the southerly airflow on the south side and the blocking effect of the terrain are beneficial to the long-term maintenance of the mesoscale shear line at the top of the terrain, which is the main reason for the persistence of heavy precipitation. |
| Key words: Extremely strong precipitation; weak weather scale; easterly wind; medium and small scale terrain |
