Influence of cut-off lows on dust transport from the Great Lakes Basin to northern China

In the context of global warming, the Great Lakes Basin in western Mongolia is undergoing escalating desertification, making it as an increasingly important dust source in Mongolia. This study investigated the dust transport from the Great Lakes Basin and its modulating circulation using ERA5 reanalysis data and applying the Lagrangian analysis tool (LAGRANTO) to the WRF-Chem simulation of two typical dust storm events in 2021 and 2023. The dust from the Great Lakes Basin and their subsequent transport toward China were primarily influenced by tropospheric cut-off lows. Cold advection to the west and warm advection to the east of the cut-off lows favored the development of near-surface anticyclones and cyclones, respectively. Between them, pronounced northwesterly and upward winds prevailed, lifting dust from the Great Lakes Basin into the troposphere. The cut-off lows transported the dust mainly eastward and southeastward, depending on their shape. A regional cut-off low deepened in the westerlies, driving dust eastward toward the Great Khingan and then in an anticlockwise direction toward the Changbai Mountain. In contrast, a zonally elongated cut-off low, associated with pronounced cold advection in the west, facilitated the near-surface anticyclone's southeastward extension. Consequently, dust from the Great Lakes Basin was primarily transported southeastward, affecting northern China. The cut-off lows influencing dust weather over northern China were predominantly located from Lake Baikal to Northeast China. Their high occurrence could have contributed to the rise in dust events over northern China in 2021 and 2023.