Reduced aerosol transport from South Asia to the Tibetan Plateau following the January 2021 sudden stratospheric warming event

Abstract

Aerosols from South Asia directly enhance glacier melt over the Tibetan Plateau. While the transboundary transport of aerosols from South Asia towards the Tibetan Plateau has been extensively investigated from a tropospheric perspective, less focus has been given to the stratospheric dimension. Here we examined the impact of the sudden stratospheric warming in January 2021 on aerosol transport from South Asia towards the Tibetan Plateau via numerical simulation. The results revealed that the aerosol transport from South Asia to the Tibetan Plateau reduced by 30%–40% following the January 2021 sudden stratospheric warming event. The eastward-propagating wave train stimulated by the stratospheric sudden warming induced an anticyclonic anomaly from the Persian Gulf to northern China, south of which easterly anomalies hindered the aerosol transport from South Asia to the Plateau. This study provides valuable insights for predicting air quality over the Tibetan Plateau. Following a sudden stratospheric warming event in 2021, transport of aerosols from South Asia to the Tibetan Plateau was suppressed as a result of changes in the tropospheric circulation, according to analyses with a weather forecasting model with a chemistry component.