华南持续性暴雨时空演变的水汽输送驱动机制研究

Persistent heavy precipitation is a heavy precipitation event that has a great impact on human society and natural ecosystems. Adequate atmospheric moisture supply is one of the key factors to the occurrence of persistent heavy precipitation. From the perspective of atmospheric moisture transport and its change, this project will study why the persistent heavy precipitation over South China has been changing spatiotemporally. Through tracking the atmospheric moisture for storm events based on the Lagrange method, the atmospheric moisture sources, transport pathways, and their changes will be analyzed, and the atmospheric moisture transport modes for different types of persistent heavy storms will be identified. The composite analysis will be conducted to find the characteristics of large-scale circulation behind the atmospheric moisture transport modes that could maintain for a long time and lead to persistent storms. The principle of the sequential processes “the large-scale circulation – the atmospheric moisture transport - the occurrence of persistent heavy precipitation” will be illustrated. The regimes of large-scale circulation and atmospheric moisture transport processes over South China under different climate warming scenarios will be compared. The dynamic and thermodynamic influence of atmospheric moisture transport leading to storms in South China will also be analyzed to explore the mechanism behind the response of atmospheric moisture leading to storms over South China to global warming. Therefore, the driving mechanism of atmospheric moisture transport to the spatiotemporal variability of persistent heavy precipitation over South China will be revealed. The study will improve the scientific understanding of atmospheric moisture transport processes and large-scale circulations associated with regional persistent heavy precipitation, and provide a scientific basis for improving the weather forecast and climate prediction of persistent heavy precipitation over South China.

持续性暴雨是对人类社会和自然生态系统影响很大的强降水事件，充足的水汽供应是持续性暴雨发生的一个关键因素。本项目从水汽输送过程及其变化的角度，探讨华南持续性暴雨发生时空演变的原因。通过基于拉格朗日方法的暴雨水汽追踪，分析持续性暴雨的水汽来源与输送路径及其变化，识别不同类型持续性暴雨的水汽输送模式；合成分析使暴雨水汽输送过程得以长时间维持的大尺度环流背景特征，探明“大尺度环流－水汽输送－华南持续性暴雨”过程的形成规律；对比分析不同气候变暖情景下华南持续性暴雨发生的大尺度环流和水汽输送过程，解析气候变暖对华南暴雨和水汽输送的动力和热力学影响，阐明华南地区暴雨水汽输送对全球变暖的响应机理；从而揭示全球变暖下区域水汽输送过程对华南持续性暴雨时空演变的驱动机制。项目研究将提高对导致华南持续性暴雨天气发生的水汽输送过程和大尺度环流的科学认识，为华南持续性暴雨的天气预报和气候预测提供科学依据。

本项目以华南地区持续性暴雨发生的水汽输送过程为切入点，以拉格朗日法水汽输送追踪、水汽过程与大尺度环流模式识别、统计分析等为手段，研究了华南持续性暴雨、区域水汽输送和大尺度环流三者之间的相互关系，初步探明了有利于华南持续性暴雨发生的水汽输送过程和大尺度环流背景及其演变规律，阐明了华南地区暴雨水汽输送对全球变暖的响应机理，揭示了区域水汽输送过程变化对华南暴雨时空演变的驱动机制；拓展和构建了基于非平稳极值统计模型的区域暴雨水汽追踪溯源和暴雨时空演变分析的理论与方法，给出了华南持续性暴雨预测的水汽输送和大气环流前兆信号；在区域水汽输送过程和大尺度环流背景的气候学变化、动力和热力学解析与暴雨时空演变的驱动机理等方面取得了一定的研究进展。