Characteristics and a mechanism of dust weather in Northern China.

In this study, the long-term characteristics of the dust weather frequency (DWF) in the ensuing spring (March–April–May, MAM) in northern China (NC) and the association with sea ice concentration in the Barents Sea (SICBS) and Arctic Oscillation (AO) in the preceding winter (December–January–February, DJF) during 1979–2021 are investigated. The results show that the dust weather in NC is mainly associated with decreased SICBS during 1982–2008 and linked with a negative AO phase during 2009–2021. Due to the decreased SICBS in the preceding winter during 1982–2008, the surface adiabatic heating excites Rossby waves to spread southward and eastward, resulting in decreased snow cover over Eurasia and more dust weather by anomalous northerly wind in the ensuing spring over NC. On the other hand, with a negative AO phase in the preceding winter during 2009–2021, the increased meridional temperature gradient at mid-latitudes tends to enhance westerly wind and cyclogenesis over NC, leading to more dust weather in the ensuing spring. Consequently, both the negative AO phase and decreased SICBS in the preceding winter correspond to strong wind and dry soil in the dust source region, which favor an increase in the DWF in the ensuing spring over NC. Studying the characteristics of the SICBS and AO could provide some clues to predict the dust weather in NC. [ABSTRACT FROM AUTHOR]