陆面过程对我国中期天气中极端气温事件影响的数值研究

Under the background of climate change, extreme temperature events have become one of the frontier and hot topics of research worldwide. A great number of studies suggest that the influence of land surface processes on extreme temperature events is substantially important. However, at present, relevant numerical studies on the synoptic scale have been relatively rarely reported...The project intends to adopt the mesoscale model, to investigate the effects of land surface process on heat wave and cold wave events at the medium-range weather scale. The main research contents are as follows: (1) the study on effects of land surface processes on heat waves in Sichuan and Chongqing area, in which quantitative description of the relative importance of the dynamical and physical processes is supposed to be presented, with the impact characteristics of land surface processes on heat waves and related mechanism revealed; (2) the study of the effects on cold waves induced by different land surface processes and different land properties such as soil and vegetation parameters during cold-wave events over China (with an emphasis on surface air temperature), which includes the analysis of the influence extent of the transfer of the surface heat, boundary layer characteristics and atmospheric circulation, and quantitative description of the relative importance of the various processes with the explanation of the mechanisms; and (3) based on the first two items and then screening out the specific process and parameters which are crucial at the land surface, the development of suitable land surface parameters and initialization scheme, in order to improve the simulations of heat and cold waves...The implementation of the project will promote the study on the effects of the land surface processes on extreme events, and provide scientific and theoretical bases for improving the prediction level of extreme temperature events.

在气候变化大背景下，极端气温事件已成为国际研究的前沿与热点。许多研究认为，陆面过程对极端气温事件的影响极其重要。然而，目前天气尺度上的相关数值研究尚较少见诸报道。.本项目拟采用中尺度模式，研究陆面过程对我国中期天气中高温与寒潮事件的影响。主要研究内容如下：(1)研究陆面过程对川渝地区热浪天气的影响，定量描述其中动力及物理过程的相对重要性，揭示陆面过程对该地区热浪影响的特征及机理。(2) 研究陆面过程对我国范围寒潮天气的影响，探讨不同陆面过程及土壤、植被等特征在寒潮过程中对气温的影响，分析其对地表热输送、边界层的特征量、大气环流等的影响程度，定量描述各种过程的相对重要性，并解释其中机理。(3)基于前两项内容，甄别出重要的具体过程及参数，发展合适的陆面参数化及初始化方案，以提高热浪及寒潮的模拟水平。.项目的实施将促进陆面过程对极端事件影响的研究，为提高极端气温事件预报水平，提供科学的理论依据。

在气候变化大背景下，极端气温事件已成为国际研究的前沿与热点。许多研究认为，陆面过程对极端气温事件的影响极其重要。本项目采用中尺度模式ARW，研究了陆面过程对我国中期天气中高温与寒潮事件的影响。主要研究内容及结果结论如下：(1)研究了陆面过程对川渝地区短中期热浪天气的影响，定量描述了其中动力及物理过程的相对重要性，发现高温事件中陆面引起的（受地形影响显著）非绝热加热最为重要，而绝热过程基本与之相平衡，平流过程不重要，揭示了陆面过程对该地区热浪影响的特征及机理。(2) 研究了中期天气尺度上陆面过程对我国范围寒潮的影响，探讨陆面过程在寒潮过程中对气温的影响，分析其对地表热输送、边界层的特征量、大气环流等的影响程度，定量描述各种过程的相对重要性，并解释了其中机理。结果同时表明，陆面过程扰动可引起的冷空气路径、到达长江中下游地区空气内能及动能的较大变化。(3)基于前两项内容，对川渝地区甄别出了重要的具体影响过程，研究了合适的陆面参数化及初始化方案，以提高热浪及寒潮事件的模拟水平。 综上，项目的实施对加深陆面过程对极端事件影响的理解，提高极端气温事件预报水平，可提供一定的科学理论依据。