青藏高原南北部沙尘气溶胶时空变化特征的对比研究

Dust aerosols have significant impacts on the climate and environment of the Tibetan Plateau (TP) and the broader Northern Hemisphere. Dust aerosols are shown to distribute differently over the northern and the southern TP. However, as existing research generally considered the TP as a whole, variation patterns of dust aerosols could be missed. With the surface observations and satellite data, we aim to compare the vertical distributions of dust aerosols in the atmospheric boundary layer and free troposphere during the past decade. Considering the wetting trend over the northern TP impacted by the westerlies and the drying trend over the southern TP by the monsoon system, this study aims to get the inter-annual variations and long-term tendency over the southern and northern TP since the middle of the 20th century. This study can also indicate the key factors for the temporal-spatial characteristics of dust variations over the northern and the southern TP. This study will deepen the understanding of the temporal-spatial characteristics, which can then serve as the basic knowledge and scientific reference for climate simulation of the impact of dust aerosols on the climate environment in Asia and the Northern Hemisphere.

沙尘气溶胶对青藏高原和北半球的气候环境有重要影响。青藏高原南北部的沙尘气溶胶分布存在显著差异，但现有研究通常将高原作为一个整体，这可能会造成沙尘气溶胶变化信息的部分缺失。本项目拟结合地面台站观测数据和卫星观测资料，对比分析高原南北部近十年来大气边界层内和自由对流层沙尘气溶胶的空间变化特征；结合高原北部西风影响区变湿和南部季风影响区变干的气候背景格局，对比分析20世纪中期以来高原南北部沙尘的年际和长期变化趋势，并分析揭示青藏高原南北部沙尘时空变化的主要影响因素。本项目的开展将有助于进一步深化对高原上空沙尘气溶胶时空格局的认识，为沙尘气溶胶对亚洲区域和北半球气候环境影响的数值模拟等工作提供一定的理论基础和科学依据。

沙尘气溶胶对青藏高原和北半球的气候环境有重要影响。在本项目（编号41805127）支持下，围绕青藏高原沙尘变化及影响因素开展相关研究工作。利用地基观测网络与卫星遥感等数据，结合ERA、NCEP再分析资料以及海温数据，对青藏高原春季沙尘通量进行了定量估算，探讨青藏高原和周边干旱半干旱地区沙尘气溶胶年际变化及其物理机制。研究结果发现：青藏高原春季沙尘通量呈现显著下降趋势，高原上空沙尘通量主要受到来自塔里木盆地沙尘的影响，而青藏高原对流层中部（>6km）以上高度的沙尘还与上风向区域的印度半岛西北部地区以及中亚地区有关。北大西洋冬季海温三极子通过影响高原周边沙尘源区春季的沙尘活动以及源区向高原传输的大气环流形式，进而与青藏高原春季沙尘年际变化密切相关。研究结果揭示了北大西洋海温变化对青藏高原春季沙尘变化的影响机制，对认识亚洲沙尘的全球传输及其气候环境影响具有重要科学意义，能够为区域至全球尺度气候模拟提供科学参考。