东亚沙尘分布、源汇及输送特征的模拟研究

发布时间：2018-07-13 16:34

【摘要】：采用全球气溶胶模式(GOCART)模拟结果,讨论了东亚地区沙尘气溶胶时空分布、排放与沉降以及区域输送特征.结果表明,中国境内沙源主要位于塔克拉玛干沙漠、河西走廊及河套地区.排放强度春季最大,夏季和秋季逐渐减小,冬季最弱,且强度逐年减弱,区域年平均排放为581Tg/a.模拟的沙尘光学厚度(AOD)分布与卫星观测具有很好的一致性,其中塔克拉玛干沙漠AOD大值与沙尘暴活动密切相关,其出现时间最早,持续时间最长.区域平均而言,干沉降和湿沉降可以分别清除77%和22%的沙尘排放,其中沙尘源区干沉降起主导作用,远离源区的东北及西北太平洋,湿沉降更加重要.沙尘大粒子主要通过重力干沉降移出,而湿沉降对小粒子贡献超过60%.重力干沉降全年(特别是春季)起主导作用,对流降水湿沉降在夏季作用显著增强,总体来说,沙尘总沉降速率逐年减小.东亚沙尘气溶胶通过3条输送带自西向东传输,可以影响我国华北、华中和华南.对散度的研究表明,气溶胶平流项对沙尘源区气溶胶辐散作用较大,沙尘排放显著影响该地区沙尘的输送和AOD;而塔里木盆地西侧沙尘辐合中心是风场辐合辐散项导致的,说明地形和风场对该地区沙尘输送和AOD很重要.
[Abstract]:Using the global aerosol model (GOCART) simulation results, the spatial and temporal distribution, emission and deposition of dust aerosols in East Asia and the characteristics of regional transport are discussed. The results show that the sand source in China is mainly located in Taklimakan Desert, Hexi Corridor and Hetao area. The emission intensity was the largest in spring, gradually decreased in summer and autumn, and the weakest in winter, and the intensity decreased year by year. The average annual emission in the region was 581Tg / a. The simulated optical thickness of sand dust (AOD) is in good agreement with satellite observation. The AOD of Taklimakan desert is closely related to the sandstorm activity, and its occurrence time is the earliest and the duration is the longest. On the regional average, dry deposition and wet deposition can eliminate 77% and 22% of dust emissions respectively, among which dry deposition plays a leading role in the source area, far from the source region of the northeast and northwest Pacific Ocean, wet deposition is more important. Dust particles are moved out mainly by gravity dry deposition, while wet deposition contributes more than 60% to small particles. Gravity dry deposition plays a leading role throughout the year (especially in spring), and the effect of convective precipitation and wet deposition increases significantly in summer, and generally, the total rate of dust deposition decreases year by year. East Asian dust aerosols are transported from west to east through three conveyors, which can affect North, Central and South China of China. The study on divergence shows that the aerosol advection term has a great effect on aerosol divergence in the source area of sand dust, and dust emission has a significant effect on dust transport and AOD.The west side of Tarim Basin is caused by convergence and divergence term of wind field. It shows that topography and wind field are very important for dust transport and AOD in this area.
【作者单位】：南京信息工程大学中国气象局气溶胶与云降水重点开放实验室;江苏省气候中心;南京信息工程大学气象灾害预报预警与评估协同创新中心;中国气象局广州热带海洋气象研究所;
【基金】：国家自然科学基金资助项目(91337101,41590873,41505052)
【分类号】：X513

【相似文献】