The Simulation Study On Distributions And Variation Characteristics Of Dust Emissions In The Tibet Plateau

The Tibet Plateau is located in the mid-latitude key location ,at the same time it has the huge height effect, and if it is an important part of the dust source regions because of its efficient remote transmission capacity, which can significant impact on the global climate potentially, and compensate the defect that the global simulation of dust flux is much lower than observation.In this article, according to the latest China desert sand distribution, the underlying surface(landuse) and the sand erosion index(erod) of the Tibet Plateau under the WRF/Chem model were improved.On the basis of the Shao scheme,we expanded the scale of dust particles to 100 ?m ,and then simulated the dust aerosol in 1961 -2015 day by day of the Tibetan plateau, we got the following conclusions: 1)The improved model can invert the temporal and spatial characteristics of the dust in the Tibet Plateau, and the simulation results are consistent with the observation;2)The dust source regions are mainly distributed in the northwest plateau, southern Changthang Plateau, Yarlung Zangbo River and its tributary valley, and Qaidam Basin.The distribution of dust aerosol emissions in spring, autumn, and winter roughly centered on the northern Tibet Plateau to the southeast direction,The Qaidam Basin is the strongest area in the Tibet Plateau during spring, summer and autumn.The emission position with the interdecadal variation is not obvious, the difference mainly concentrated in the south Changthang Plateau and the Qaidam Basin;3)The monthly variation of dust emissions with particle size below 100 ?m show a single peak type, with the largest in February and the lowest in August. The seasonal variation is characterized by high emission in winter and spring and low emission in summer and autumn.Unlike the arid regions of northern China, the peak of the latter is from April to May, the low value appears in January;4)The annual mean emission of the Tibet Plateau is 220 Tg which has experienced an slight rising tendency from 1961 to 2015,it accounts for about 17% of annual mean emission in the East Asian region that including the Tibet Plateau (1260 Tg);The monthly mean contribution rate of the Tibet Plateau to East Asia is 22%with more than 30% in winter ,the contribution rate of January and February can exceed 50%. It indicates that the Tibet Plateau is an important dust source region;5)The dust with particle size below 20 ?m can be remote transfered,it's variation trend is different from the dust with particle size below 100 ?m. The emissions proportion of small particles in summer more than in winter, such as accounts for only 2% of the emissions in February, has reached 14% in August;Under the influence of the westerly jet, the dust aerosols in the East Asia are distributed eastward to Japan, the Korean Peninsula and the Korea. In the 800 hPa and 700 hPa areas, the dust is mainly transported from the arid regions of northern China, but in the 500 hPa height dust conveying effect of plateau is more significant;6) The Tibet Plateau is not only an important source of dust, but also it is an important source of dust aerosols over East Asia because of its huge height effect,it may have a significant impact on the global climate.