东北印度洋大气粉尘现代沉积过程分析  

Modern Deposition of Atmospheric Dust in the Northeast Indian Ocean

作　　者：杜恕环 牛东风[1] 黄锦萍 潘子锐 黄日辉 陈碧珊 Du Shuhuan;Niu Dongfeng;Huang Jinping;Pan Zirui;Huang Rihui;Chen Bishan(School of Geographical Sciences,Lingnan Normal University,Zhanjiang 524048,China;Key Laboratory of Ocean and Marginal Sea Geology,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 510301,China;School of Geography and Remote Sensing,Guangzhou University,Guangzhou 510006,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]岭南师范学院地理科学学院,广东湛江524048 [2]中国科学院南海海洋研究所,中国科学院边缘海与大洋地质重点实验室,广州510301 [3]广州大学地理科学与遥感学院,广州510006 [4]中国科学院大学,北京100049

出　　处：《热带地理》2022年第10期1609-1616,共8页Tropical Geography

基　　金：海南省科技计划三亚崖州湾科技城联合项目(2021JJLH0048);中国地质大学海洋地质资源湖北省重点实验室开放基金(MGR202101)。

摘　　要：海洋大气粉尘是海气相互作用的桥梁。由于现代大气粉尘沉积在时空尺度上具有广泛性和可观察性,使其成为研究海洋海气相互作用的重要基础和手段。而位于世界屋脊青藏高原南翼的东北印度洋,是全球海洋生产力最强和生物多样性最丰富的海域之一,然而,关于海洋现代粉尘的研究还未见相关的报道。文章通过对东北印度洋2020年9―11月的大气粉尘进行走航收集,分析大气粉尘样品沉积通量,利用空气粒子模型模拟粉尘传播途径,对粉尘石英颗粒进行扫描电镜及能谱分析;再结合全球遥感数据,首次对东北印度洋大气粉尘沉积的现代过程进行探讨。研究发现,东北印度洋大气粉尘沉积通量变化在221~1221 mg/cm^(2)/d之间,研究期内粉尘日沉积通量最高值出现在冬季风盛行的11月中旬,而最低值则在夏季风控制的9月下旬,前者通量约是后者6倍;粉尘沉积通量变化主要受粉尘源区距离的影响,而粉尘粒径大小和风力强度有关。空气粒子模拟结果显示,粉尘的传播过程受大气环流系统的季节性和区域性控制,结合大气气溶胶数据可进一步探讨粉尘的源汇过程。此外,现代粉尘石英颗粒表面结构具有明显的风成环境沉积特征,石英颗粒磨圆度较好,具有蛇曲脊或“U”型坑,明显区别于水成环境下石英颗粒磨圆度差,具有贝壳状断口及“V”型坑等特征,可作为在沉积物中区分不同搬运动力组分的依据。Atmospheric dust in the ocean is a bridge for air-sea interaction,which is an important basis for the study of this phenomenon due to extensive and observable space-time scales.The northeast Indian Ocean,located in the southern wing of the"roof of the world,"the Tibetan Plateau,is among the seas with the strongest marine productivity and richest biodiversity in the world.However,there have been no relevant reports on the study of modern marine dust.This study discussed the modern process of atmospheric dust deposition in the northeas Indian Ocean for the first time,in terms of deposition flux,transport path simulation,scanning electron microscopy,and energy spectrum analysis based on atmospheric dust samples collected from September to November 2020 in the study area.The findings showed that the dust deposition flux in the northeast Indian Ocean varied between 221-1,221 mg/cm^(2)/d.The maximum daily dust deposition fluxes appeared in the middle of November when winter monsoon conditions prevailed,and the minimum value appeared in late September under summer monsoon conditions;the former flux was approximately six times that of the latter.The dust deposition flux change was primarily affected by the distance of the dust source,whereas the dust particle size was related to wind intensity.The results of air particle simulation indicate that the dust transport process is controlled by seasonal and regional atmospheric circulation systems,and is specifically dominated by the Indian monsoon in the northeast Indian Ocean.The study area deposits more dust with nutrient elements from the Asian continent which promotes the ocean’s primary productivity and enhances its carbon sequestration capacity.Furthermore,the surface of quartz particles from modern atmospheric dust shows a unique structure in the aeolian environment good quartz grain roundness,a meander ridge,and a U-shape.These characteristics are markedly different from those in a fluvial condition,such as poor roundness,conchoidal fracture,and a V-shape,which can

关 键 词：东北印度洋 海洋大气粉尘 粉尘沉积 现代过程 海气相互作用 

分 类 号：P67[天文地球—海洋地质]