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Lanzhou University (2022)

Satellite-based Asian Dust Cycle and Radiative Effect


Titre : Satellite-based Asian Dust Cycle and Radiative Effect

Auteur : 韩颖

Grade : Doctoral Dissertation 2022

Université : Lanzhou University

Résumé partiel
The Asian long-distance transport process is one of the largest dust transport activity in the world.It can sweep across the Tibetan Plateau and transport to most of China,and even across the Pacific Ocean to the Americas.On the one hand,the dust suspended in the atmosphere affects the local radiative budget through direct or indirect effects ;On the other hand,dust deposition during transport provides rich mineral elements and nutrients for the Asian continent and the Pacific Ocean,enhancing the growth of land vegetation and marine plankton.Therefore,the Asian dust cycle is closely related to the land-atmosphere-ocean biochemical cycle,and has a profound impact on regional and global ecological health,weather and climate.Currently,model simulation is an ideal tool to study the Asian dust cycle and provide information on the mechanism of dust cycle.However,due to the parameterization scheme and related assumptions,there is still a great uncertainty in the simulation results.Therefore,relevant data of dust cycle based on remote sensing observations are urgently needed to constrain and validate the model.This paper takes advantage of CALIOP polarization detection and the 3D dust optical properties data it provides to accurately extract dust aerosol from the total aerosol based on the dust and non-dust depolarization ratio thresholds ;then,combined with the dust mass extinction efficiency provided by Dust COMM,we construct a long-term 3D remote sensing dataset of Asian dust optical thickness,mass concentration and mass transport fluxes.The transport contributions of dust sources,transport characteristics and deposition fluxes of Asian dust are further studied systematically.The dust radiative heating rate over the Tibetan Plateau is also quantified by combining the SBDART radiative transfer model.The main conclusions of this paper are as follows.(1)There are two main dust transport belts in Asia,one of which runs from Central Asia in the west,through the Taklimakan desert and Gobi Desert,and extends to the North China Plain and even the Pacific Ocean.It is the strongest dust transport belt from Central Asia to East Asia and exists all the year round.The other dust transport belt started from Central and West Asia,mixed with the dust emitted from Thar Desert in South Asia,and then crossed the Hengduan Mountains and Yunnan-Guizhou Plateau before arriving southern China,which is a weaker dust transport belt.The two transport belts converge in eastern China and its downstream areas.The scope of dust transport belt is basically consistent with the location of high dust mass concentration.However,it is worth noting that the center location of dust transport belt is not always consistent with the dust mass center axis.This is because the dust transport process is not only affected by dust mass loading,but also by wind speed and terrain.(2)The dust mass transport center axis(TCA)has significant temporal and spatial variation.In the near-surface layer,the dust TCA is controlled by the topography of inland northwest China and crosses the Taklamakan and Gobi Deserts throughout the year,while with the increase of dust transport distance,the dust TCA is influenced by the location of the western Pacific subtropical high pressure and Aleutian low pressure,and moves in the range of 35-50°N throughout the yea

Mots clés : Asian dust cycle ;Dust concentrate ;Dust mass transport flux ;Dust transport contribution ;Dust budget ;Tibetan Plateau ;Dust heating rate ;

Présentation (CNKI)

Page publiée le 16 octobre 2022