Control of the aridification of the Taklimakan and Thar deserts by asynchronous tectonic uplift of the Pamirs and northern Tibetan Plateau since the Miocene

Abstract

We used a regional climate model (RegCM4) to study the impact of the asynchronous uplift of the Pamirs and the northern Tibetan Plateau (NTP) on the regional aridification of the northern and southern sides of the Tibetan Plateau since the Miocene. The intense aridification of the Taklimakan Desert since the Pliocene can be attributed to the mechanical blocking effect caused by the uplift of the Pamirs and may eventually lead to complete desertification. The uplift of the Pamirs suppressed precipitation and increased the atmospheric loading of dust over the Taklimakan Desert by about 50%. By contrast, the aridification of the Thar Desert since the Miocene can be mainly attributed to the uplift of the NTP. The uplift of the NTP modulated the location and intensity of the 700 hPa subtropical high over the Thar Desert and halved the amount of summer precipitation in this region by enhancing the dry and hot downdraft. The uplift of the NTP also intensified the aridification of the Gobi Desert and the Loess Plateau during the Miocene. The uplift-induced thermal effect suppressed precipitation by 50% and increased dust loading by 10–20% in these two regions. Our study indicates that the regional differences between the aridification processes in the Taklimakan and Thar deserts since the Miocene were affected by the asynchronous uplift of the Pamirs and the NTP. These findings provide new insights into the origin and evolution of dust source regions in Asia.