Association of spring thermal forcing anomalies in the Tibetan Plateau with dust aerosol changes over the Taklamakan Desert

Sci Total Environ. 2024 Dec 17:958:177839. doi: 10.1016/j.scitotenv.2024.177839. Online ahead of print.

Abstract

The Tibetan Plateau (TP) is significantly influencing the climate and environmental evolution regionally and globally. Adjacent to the northwestern TP, the Taklimakan Desert (TD) experiences the unique pattern of dust aerosol variations due to the deep basin terrain. However, systematic studies on how TP climate change affects TD dust aerosol variations are lacking. This study employs MERRA-2 and ERA5 reanalysis data (1991-2020) to investigate the impact of springtime TP thermal forcing on TD dust aerosol. Results indicate that the interannual variation of dust column mass densities over the TD showed an increasing trend over 1991-2020, with a significant increase in the northern TD, where the maximum value exceeded 9.51 mg m-2 per year. Thermal forcing strengthening on the northwestern TP are positively correlated with dust column mass density variations in the northern TD, while negatively correlated in the southern TD. Further comprehensive analyses indicate that strong northwestern TP thermal forcing has increased dust aerosol concentrations in northern TD, with a maximum 14 mg m-3 increase at 700 hPa, while decreasing them in the southern part. During strong SNTP-Q1 years, anticyclonic anomalies, strong updrafts, and the blocking effect of the Tian Shan Mountains, combined with high temperatures, result in dust aerosols suspended in the atmosphere over the northern TD. In contrast, during weak SNTP-Q1 years, cyclonic anomalies, strong downdrafts, and the large topography of the TP, along with inversion temperatures, contribute to dust aerosol accumulation in the southern TD. This study elucidates the mechanism of TP thermal forcing on TD dust aerosol variations, enhancing understanding of its effects on environmental and climatic changes in the TD and Central Asia.

Keywords: Climatic change; Dust aerosols; Taklamakan Desert; Thermal forcing; Tibetan Plateau.