巴丹吉林沙漠沙尘暴对大气边界层物质和能量循环的影响及其局地气候效应研究

Land - atmosphere interaction over the desert is an important member of the world's arid climate system. Due to the strong influence of dust storms upon the energy - material recycling process in the atmospheric boundary layer over the desert land surface, and the important feedback of the latter on the occurrence,development, and demise of dust storms, the project will select the Badain Jaran Desert as the study area,which is located on the northwestern edge of the East Asian monsoon region and has a major impact on China's drought and monsoon climates.Based on the previous research, and with more sophisticated means of ground and remote sensing observations and more advanced numerical models,the interactions between dust storms and the momentum, energy and material recycling processes in the atmospheric boundary layer over the desert land surface will be deeply studied, focusing upon the mechanism of dust storms strongly influencing on the dynamic and thermodynamic structures of the atmospheric boudary layer, and the important role of the land surface process and the atmospheric boudary layer structure in the physical mechanisms of the dust storm occurrence,developing and demise processes. The conceptual model will be established describing the physical mechanism of the interaction between dust storms and the material and energy cycles in the atmospheric boudary layer over the Badain Jaran Desert land surface, in order to clarify the important roles of the land-surface processes, atmospheric boudary layer structures, dust storms,and their interactions, in the climate change over the desert and surrounding areas, and to find out the physical and meteorological factors catalyzing and inhibiting the dust storms in China.

沙漠下垫面的陆-气相互作用是全球干旱气候系统的重要成员；鉴于沙尘暴对沙漠陆面-大气边界层能量-物质循环过程的强烈影响，以及后者对沙尘暴发生、发展、消亡过程的重要反馈机制，本项目拟选取位于东亚季风区西北边缘、对我国干旱和季风气候有重要影响的巴丹吉林沙漠为研究区域，基于前人的相关研究成果，结合更精良的地面和遥感观测手段，应用更先进的数值模式，对沙尘暴与沙漠陆面-边界层动量（如风廓线）、能量（如地表辐射通量、感热和潜热输送）和物质（如水汽和沙尘）循环间的相互作用进行深入研究，着重揭示沙尘暴对大气边界层动力和热力结构的强烈影响机制，以及陆面过程和大气边界层动力、热力结构在沙尘暴发生、发展乃至消亡过程中发挥的重要作用及其物理机制，最终建立巴丹吉林沙漠沙尘暴与陆面-边界层能量-物质循环相互作用机理的概念模型，以期更深入地揭示这种相互作用对沙漠及周边气候的重要影响以及促发和抑制我国沙尘暴的物理气象因子。

沙尘暴是频发于我国干旱半干旱区的重要灾害性天气，沙漠作为该区的主要下垫面之一，是沙尘的重要源地；本项目特以巴丹吉林沙漠为典型，针对其上发生的沙尘暴对大气边界层物质、能量循环的影响机制进行研究，有利于加深理解沙尘暴的发生机制及其环境和气候效应，以期最终服务于提高沙尘暴的业务预报水平。在所获基金和依托单位的支持下，本项目主要完成了以下数方面的研究工作：1）巴丹吉林沙漠地区降水与沙尘暴的气候特征及其相关性研究，主要揭示了该区域冬、春季降水增多会明显抑制当季及下季沙尘暴的发生，但夏季降水与当季和秋季沙尘暴一致减少的变化趋势掩盖了前者对后者的抑制作用；2）基于常规气象观测数据，建立了一套能够客观、多维、定量反映边界层气象对沙尘暴影响特性的普适性物理量，并据此分析了影响特性的时空变化特征及其成因；3）基于以上边界层气象对沙尘暴的影响特性，建立了一套某地发生沙尘暴可能性的普适性估算方案，并据此给出特定边界层气象条件下当地能否发生沙尘暴的有效预报判据；4）将巴丹吉林沙漠作为重点研究区域，用WRF_Chem模式对近期我国西北地区的一次典型沙尘暴进行了细网格模拟。