Spatial And Temporal Distribution Characteristics Of Dust Aerosols And Their Heating Rates In The Taklimakan Desert And The Qinghai-Tibet Plateau

Based on the products of MERRA-2 aerosol reanalysis and CALIPSO aerosol profiles,the temporal and spatial distribution characteristics of dust aerosol mass concentration,optical depth,extinction coefficient profile and heatin rate over the Taklimakan Desert(TD)and the Tibetan Plateau(TP)from 2007 to 2020 were analyzed combined with the radiative transfer model SBDART.In this paper,the climatic characteristics and chan es of vertical distribution of dust aerosols over the TD and TP was revealed by comprehensive use of satellite and reanalysis data.Combined with numerical simulation,the radiative heatin effect of dust can be understood more clearly,which is conducive to understandin the influence mechanism of dust on atmospheric thermal structure in this re ion.The main conclusions are as follows.(1)As the hi h-value center of dust concentration,the annual surface(column)mass concentration of dust over TD was above 100×m^-3(0.2×m^-2),and the seasonal concentrations decreased sequentially from sprin to winter.In sprin and summer,the dust concentration in the northern part of the TP was si nificantly influenced by that of the TD.In summer,the dust concentration over the southern slope of the TP was si nificantly affected by the dust from the Thar Desert.The Qaidam Basin was the center of hi h dust concentration over TP.From 2007 to 2020,the dust surface mass concentration increased obviously in the northern and western TD,while decreased si nificantly in most parts of the TP.In addition,the dust column mass density in TD decreased si nificantly from 2007 to 2016.(2)The multi-year avera e dust aerosol optical depth(DAOD)was hi her than 0.3 over TD,lower than 0.1 in most re ions of TP,and hi her than 0.2 over the Qaidam Basin.There is a lon standin dust layer in 1?3 km above TD,with the thickness deepest in sprin.In summer,the influx of dust from the Thar Desert and the Indo-Gan etic Plain increased the dust concentration over the southern slopes of TP.In sprin and winter,the dust extinction coefficient (?_D)showed a weak upward trend over the study area,while a decreasin in autumn.The stron est increasin of (?_D)appeared over the TD in sprin and over the southern slope of the TP in winter.(3)The annual avera e dust heatin rates(DHR)were 2.8 and 1.8 K×day^-1 over TD and TP,respectively.It showed the stron est DHR in sprin,followed by that in summer.The maximum of DHR reached nearly 8 K×day^-1in TD in sprin.The dust heatin effect on the northern slope of TP was much stron er in sprin and summer.The dust heatin layer over the Qaidam Basin can mer e with that from the TD.The dust from the Indo-Gan etic Plain si nificantly heated the atmospheric layer of 4?5 km over the southern TP in autumn.The dust heatin effect shows its stron est from March to June over both TD and TP.The hei ht of the lar est DHR over TD experienced a first up and then down trend,with the maximum in July.The DHR showed an increasin trend in sprin and winter and decreasin in summer and autumn over both TD and TP.An increasin trend of DHR also appeared over the southern slope of TP in winter.As to layer avera es of DHR over TD,it shows the most intense heatin effect in the layer of 2?4 km in sprin and summer,which decreased its intensity and hi h-value area from sprin to winter.Over TP,the stron est DHR layer appears at 4?6 km above Qaidam Basin,and it reached the hi hest in sprin.