Advances in Climate Change Research (Dec 2022)
Links between winter dust over the Tibetan Plateau and preceding autumn sea ice variability in the Barents and Kara Seas
Abstract
The Tibetan Plateau (TP) is characterized by heavily local dust activities, however, the mechanism of interannual variations of winter dust frequency over the TP remain poorly understood. Previous studies showed the autumn Arctic sea ice could significantly influence the winter climate over Eurasia. Whether autumn sea ice affects winter dust activity over the TP or not? Here, we used an integrated surface database to investigate possible mechanisms for interannual variability in the frequency of winter dust events above the TP. This variability, which is thought to be mainly caused by local dust emissions, shows significant correlations with sea ice concentration (SIC) in the Barents and Kara Seas during the preceding autumn. Low Barents–Kara SIC is accompanied by reduced snow depth over northern Eurasia between autumn and winter, which can enhance the Eurasian mid-latitude westerly jet stream. This strengthening increases the cyclogenesis and occurrence of strong surface wind speeds in winter, especially over the TP. In addition, a lower SIC is closely associated with reduced precipitation and snow cover in late autumn and winter over the TP, which in turn enhances warming of the land surface and reduces the area of frozen ground. These anomalies in atmospheric circulation patterns and local surface conditions promote dust events above the TP during winter. The ensemble means of Atmospheric Model Intercomparison Project experiments from Phase 6 of the Coupled Model Inter-comparison Project and the Community Atmosphere Model version 4 can generally reproduce the atmospheric circulation anomalies associated with decreased Barents–Kara SIC. This study reveals the crucial effect that SIC anomalies in the Barents and Kara Seas have on winter dust activities over the TP.
