Impact of massive topography on the dust cycle surrounding the Tibetan Plateau

Abstract

The Tibetan Plateau (TP), the most massive topographic feature in the world, is located at the crossroads of the Asian dust cycle and plays an important role in dust transport via topography. However, the difference in the Tibetan Plateau's topographical effect on and mechanism of dust transport from the northern and southern TP are not clear. Here, through the Tibetan topography experiments by a model, we propose a mechanism for the differential impact of the TP on the dust cycle sourced from northern and southern deserts neighboring the TP. Dust emitted from the southwestern Taklimakan Desert (TD), which is located on the north side of the TP, is mainly transported by the strong upslope winds caused by Tibetan topography to the upper layers. Consequently, it results in less dust suspended in low layers but more dust suspended in upper layers. In addition, the “narrow pipe effect” caused by massive Tibetan topography in the Hexi Corridor induces stronger dust activity in the Gobi Desert. In addition, on the southern side of the TP, more intensive dust emissions in the Great Indian Desert (GID) are induced by Tibetan topography; simultaneously, whole layers are lifted to the upper troposphere through the “heat pump effect” of the TP where the Tibetan topography acts as a “ladder”. Essentially, the existence of Tibetan topography can change the near-surface wind speeds by adjusting the atmospheric circulations, which changes the dust emission location in the TD and strengthens dust emissions in GID and Gobi Desert. This study can provide clues for a better understanding of the impact of TP topography on the dust cycle.