Recent years of below-average Arctic sea-ice have been proposed to be linked to severe cold winters over Eurasia. However, the causality and mechansims of this connection are unclear. Two general pathways have been proposed through which reduced sea-ice could induce cold winter, namely, the tropospheric and stratospheric pathways. Here, we sought to measure the relative importance of stratospheric and tropospheric processes in this connection. Using observations and model simulations, we find that distinct tropospheric and stratospheric mechanisms contribute roughly equally to the Eurasian winter cooling in response to reduced sea-ice. In the tropospheric pathway, we find that the Siberian High, an important surface high pressure system for Eurasian winter climate, is enhanced by the reduced Arctic sea-ice. This favors the intrusion of cold polar air-mass into Eurasia. In the stratospheric pathway, the stratospheric polar vortex, a strong wintertime circumpolar westerly system (∼15-40 km), is shifted towards Eurasia by the reduced sea-ice, which also favors the cold anomalies over Euraisa.
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Nieuwe interessante studie over de link tussen zeeijs Noordpool en de tweede helft van de winter. Gaat m.n. op voor het oosten van Azië.