2019 年8 月阿克苏罕见翻山大风精细特征及成因分析
Fine characteristics and cause analysis of rare gale over Tianshan Mountains over Aksu Prefecture in August, 2019
摘要
南疆中西部的阿克苏地区，由于地理位置及地形的原因，在地面冷空气很强的时候，很容易就会出现翻山大风。为深入了解阿克苏翻山大风的机理，提高此类灾害性大风的预报能力，针对2019年8月15—18日出现的一次罕见翻山大风天气过程，利用常规气象观测资料、探空观测资料、模式预报资料、NCEP逐6 h格距1°×1°的再分析资料和阿克苏站、托万克提根洪沟站2个地面自动气象站的逐小时风向风速资料，对本次大风的精细特征及其影响系统和动力、热力条件进行了分析。结果表明：（1）此次大风是在东欧阻塞高压发展加强、中亚低涡长时间维持并3次分裂东移的形势下，由高空急流和低层冷平流的共同作用使冷空气的势能向动能转化而引发的持续性大风。（2）过程中出现了3次大风波动，均是高空槽引导冷空气翻越天山而形成，前2次是短波槽引起，大风持续时间短，第3次是主槽东移引发，大风持续时间长。（3）第一次大风波动中有对流性雷暴大风叠加，瞬间阵风达12级。（4）高空急流引起的强垂直运动和次级环流、中层辐合及低层辐散有利于大风的加强和维持。
Abstract
Because of its unique geographic location and landform, Aksu Prefecture, located in the midwest of southern Xinjiang, is prone to gale weather when the surface cold air is forceful. For better knowledge of its mechanism, the fine characteristics and its effect system, and dynamic and thermal conditions of the rare gale over the Tianshan Mountains over Aksu Prefecture from August 15th to 18th , 2019 are assessed, based on conventional and intensive detecting, radiosonde observation, and the National Center for Environmental Prediction reanalysis data. The outcomes are as follows. This gale is known as a persistent gale. The blocking high over Eastern Europe has developed to strengthen against the circulation background, and the Central Asia low vortex has been maintained for a long time, with three short waves split and moving east. It is caused by movement energy converted from cold air potential energy when the upper-level jet stream and low-level cold advection work perfectly together. There are three gale waves, all of which are caused by cold air being guided over the Tianshan Mountains by the upper trough. The gale lasted only a few minutes for the first two times, triggered by a short-wave trough. The gale last time lasted for a long time, triggered by the main trough moving east. For the first time, the gale wave was composed of convective thunderstorm winds with instantaneous wind speeds reaching the grade 12. It benefits the strengthening and preservation of the strong vertical motion and secondary circulation caused by the high-level jet, middle-level convergence, and low-level divergence.关键词
翻山大风/雷暴大风/动力条件/热力条件/阿克苏引用本文复制引用
肉孜·阿基,李如琦, 于碧馨.2019 年8 月阿克苏罕见翻山大风精细特征及成因分析[EB/OL].(2023-03-14)[2026-04-02].https://chinaxiv.org/abs/202303.00134.学科分类
大气科学（气象学）
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