中纬度地区大气重力波的活动特征及其与湿对流过程的耦合机制

重力波是大气中的基本波动之一，能起到传输能量和动量等重要作用，并影响中尺度对流系统的活动，引起大风、冰雹、暴雨等灾害性天气。然而，国际上对其主要特征和相关机制的认识还十分有限。因此，本项目将针对这一空白系统研究中纬度地区大气重力波的活动特征及其与湿对流过程的耦合机制。首先，利用欧洲中期天气预报中心的高分辨率全球气候模式模拟数据和再分析资料，针对全球中纬度地区的对流层和平流层，统计归纳大气重力波的时空分布特征。然后，采用多种统计方法建立定量识别重力波扰动信号的结构、波谱和传播特征的工具，揭示其主要特征参数，并且比较不同数据结果的异同。最后，针对中国选取典型个例，基于观测和数值模拟，使用光线追踪模型等工具研究重力波发生机制，揭示中纬度地区大气重力波与湿对流过程的耦合机制。本研究成果将提高对中纬度地区大气重力波动力学的科学认识，并为改善重力波参数化方案、提高强对流天气预报准确率提供有益的参考。

As one of the basic oscillations in the atmosphere, gravity waves play an important role in transporting energy and momentum, and affect the activities of mesoscale convective system, causing severe weather such as high wind, hail and rainstorm. However, the understanding of their main characteristics and associated mechanisms is still very limited. In order to fill this gap, the proposed project will comprehensively investigate the main characteristics of atmospheric gravity waves in midlatitudes and their coupling with moist convection. Firstly, with the collected high-resolution climate model simulation data and reanalysis data from the European Centre for Medium-Range Weather Forecasts, the spatial and temporal distribution of atmospheric gravity waves will be investigated for troposphere and stratosphere in midlatitudes of both hemispheres. Secondly, a variety of statistical methods will be adopted to quantitatively identify the structure, spectrum, and propagation characteristics of the gravity wave signals, to reveal their main characteristic parameters, and to compare the similarities and differences of the results among different data. Thirdly, based on observations and numerical simulations, this research will carry out experiments for the selected gravity wave events in China, to investigate their potential source mechanisms according to tools such as ray tracing models, and to study their coupling with moist convection in midlatitudes. This project will further improve the understanding of the dynamics of atmospheric gravity waves in midlatitudes and provide useful references for improving gravity wave parameterization, as well as the performance of severe weather forecast.