昆明准静止锋进退机理研究

Kunming Quasi-Stationary Front (KQSF) is a frequent weather event in the Eastern Yunnan-Guizhou Plateau in Southwest China, it usually located in the region between Sichuan Yibin, Guizhou Singren and Yunnan Guangnan, and quasi north-south oriented. It not only leaded the significant differences in climate between Yunnan,Guizhou,Sichuan and Guangxi province., but also brought frozen rain and snow in a wide range in Winter and Spring, heavy rain and strong convective weather in neighbour region in Summer and Autumn. It was occurring while the Yunnan-Guizhou Plateau prevented cold air continuing moving westwards, beside of terrain, the thickness of cold air and the intensity of warm air mass which located at the both side of the front, also take an important role in keeping, strengthening, declining the front. In the past a few decades, there were a lot of studies on its structure, activity pattern, weather phenomena caused by it, etc., and got some basic understandings. But there were a few studies on the role of terrain, the interaction between cold and warm air for the Kunming Quasi-Stationary Front. It resulted in lacking of reliable theoretical basis and quantitative indicators for KQSF activities in operation. The activity law of KQSF has not been mastered in full. The applicant wants to use a traditional diagnostic methods and numerical simulation techniques to get a further deep understanding for its mechanism.

昆明准静止锋是中国西南地区东部云贵高原上一个经常出现的天气系统，通常位于四川宜宾、贵州兴仁和云南广南一带，呈准南北向。它不仅导致云、贵、川和广西较大的气候差异，而且随着该天气系统的东西向摆动，常造成其东侧区域的大范围冰冻雨雪天气（冬春季节）和其附近的大-暴雨、强对流天气（夏秋季节）。昆明准静止锋是云贵高原阻挡冷空气向西移动的产物，它的维持、增强西进和减弱东退除了与地形阻挡因素外，还与锋后冷空气的厚度、锋前暖气团的强度有关。过去几十年里，人们对昆明准静止锋的结构、活动规律、造成的天气等做过许多研究并有了一些基本的认识。但地形的作用、冷暖气团的强弱以及它们之间的相互关系对准静止锋进退机的影响及其机理研究较少，导致预报业务中缺乏可靠的理论依据和定量指标，准静止锋的活动规律并未完全掌握。申请者希望利用传统的诊断方法和现代数值模拟技术，深入研究昆明准静止锋进退机理，提升对其活动规律的认识。

昆明准静止锋是中国西南地区云贵高原上一个经常出现的天气系统，过去人们对它活动规律有一些基本认识，但地形的作用、冷暖气团的强弱以及它们之间的相互关系对准静止锋生消和进退的影响研究较少。本项目深入研究了在云贵高原大地形作用下昆明准静止锋的结构、生消和进退天气学诊断、锋面活动状况与大尺度海气分布关系、地形敏感性和暖气团敏感性数值模拟试验、与云南寒潮、雨雪、强对流天气关系等，提升了对其活动规律的认识。其中有三个方面的工作较过去有显著创新：一是锋面的客观识别，它解决了在高原复杂地形下对锋面位置的准确判断，同时改变了由于工作量大导致对昆明准静止锋活动规律分析的限制和主观判断上带来的差异，为利用大样本、长时间序列客观研究准静止锋天气学奠定了基础。二是利用锋生函数诊断方法，对锋生函数以及各项在昆明准静止锋生消过程中的贡献与作用做了详细的分析，揭示了冷暖气团在云贵高原的作用下，热力和动力场的垂直变化和水平梯度分布特征，建立了昆明准静止锋维持和进退机理的概念模型。三是开展了数值模拟试验，根据模拟试验结果解释了高原大地形对昆明准静止锋的生消和进退所起的作用，以及冷暖气团之间的强弱对比对锋面进退的影响。项目已公开发表的论文10篇，出版《昆明准静止锋》专著1部，对相关领域的研究具有很好的参考价值。