Enhanced Arctic moisture transport toward Siberia in autumn revealed by tagged moisture transport model experiment

Rapid Arctic warming has altered the regional hydrological cycle through reduction in Arctic sea ice. Observational and modeling efforts provided evidence that the enhanced evaporation from the Arctic Ocean could increase snowfall over high latitude terrestrial zones. However, questions remain regarding the amount of equatorward moisture transport and its change over the decadal timescale. Here we show that the transport of atmospheric moisture to Siberia that originated from Arctic Ocean evaporation has increased significantly in autumn to early winter during 1981–2019 when substantial sea ice retreat was observed. The enhanced Arctic moisture content is found in western Siberia in September, consistent with the observed increase in snow cover investigated in earlier studies. Meanwhile, the annual maximum daily amount of Arctic moisture shows a sharp increase in eastern Siberia during October–December associated with cyclonic activities along coastal regions. Our results suggest the importance of monitoring equatorward moisture transport during snow accumulation seasons because it could enhance local snowstorms as evaporation from the Arctic Ocean increases in the near future.

Tomonori Sato, Tetsu Nakamura, Yoshihiro Iijima, Tetsuya Hiyama