基于冰芯记录与遥感数据的近期青藏高原粉尘变化研究

冰芯中的微粒记录是恢复过去大气粉尘变化的独特信息,选取青藏高原的西部(慕士塔格)、中部(唐古拉)、南部(珠穆朗玛峰、达索普和宁金岗桑)为研究地点,结合遥感数据(气溶胶指数)和冰芯记录(粉尘质量浓度与沉积通量)探讨过去几十年来青藏高原大气粉尘在时间上和空间上的变化.结果表明:青藏高原上气溶胶指数从北向南、从西向东减少,靠近塔克拉玛干沙漠的地区气溶胶指数数值最大,藏南地区最低,与西风环流在高原的传输路径和源区的地理分布一致.冰芯中粉尘质量浓度表现为:高原中部>高原西部>高原南部,而沉积通量表现为高原西部>高原中部>高原南部,与气溶胶指数相一致.通过冰芯中的粉尘沉积通量记录与气溶胶指数的相关分析,发现在年尺度上仅有唐古拉地区表现出较好的相关性,而在其他地区无明显相关关系.经过3点滑动平均后,高原各地的这种相关性均有所提高:慕士塔格地区相关系数为0.49(P=0.13);唐古拉地区的相关系数为0.87(P<0.001);宁金岗桑地区的相关系数为0.68(P=0.03).这种相关性为通过冰芯记录来反演更长时间尺度的青藏高原上气溶胶指数提供了基础.

Dust Change over the Tibetan Plateau in Recent Years Using Ice Core Records and Satellite Remote Sensing Data

Particle records of ice cores are the unique information which can recover atmospheric dust change in the past,while using remote sensing data is a very effective way to research the characteristics of dust in a large scope,especially on the Tibetan Plateau where ground-based observations are scarce.Selecting the west section(Muztagata),the central section(Tanggula),and the south part(Mt.Qomolangma,Dasuopu and Noijinkansang) of the Tibetan Plateau for the research sites and combining with the remote sensing data(aerosol index) and ice core records(dust concentration and flux),the temporal and spatial changes of the atmospheric dust over the plateau are discussed in this paper.It is found that aerosol index decreases from north to south,and from west to east over the Tibetan Plateau,and the maximum aerosol index value takes place near the Taklimakan desert,and the minimum one takes place on the south of the plateau,in line with the westerly circulation path in the highlands and the geographical distribution of the source areas.Dust concentration in ice cores in the central part of the plateau is greater than that in the west,and much greater than that in the south.However,dust flux in the west of the plateau is greater than that in the central part,and much greater than that in the south,in accord with the aerosol index.Between dust flux and aerosol index there is good correlation in the Tanggula area only in the year scale,and no obvious correlations can be seen in other areas.After 3-year moving average,the correlation coefficient is 0.49(P=0.13) in the Muztagata,0.87(P<0.001) in the Tanggula and 0.68(P=0.03) in the Noijinkansang.This correlation provides the basis for inverting aerosol index from the ice core records in longer time scales on the Tibetan Plateau.