Influence of spring Arctic sea ice melt on Eurasian surface air temperature.

This study investigates the association of spring (April–May) Arctic sea ice melt with simultaneous surface air temperature (SAT) over mid-high latitudes of Eurasia from 1979 to 2019 by using observational datasets and simulation experiments. The results show that spring SAT anomalies associated with Arctic sea ice melt display a dipole pattern over Eurasia. A high Arctic sea ice melt corresponds to positive SAT anomalies over northern Eurasia and negative SAT anomalies over most of Asia. The 500 hPa geopotential height anomalies exhibit a wave train structure, and a dominant positive center is located over the Ural Mountains with two negative centers over East Asia and western Europe. This atmospheric circulation anomaly differs from the traditional Eurasian pattern and the North Atlantic-Eurasian teleconnection pattern due to their different spatial modes. Simulation experiments forced by Arctic sea ice anomalies reproduce the major characteristics of observational associations. Observations and numerical simulations indicate that high Arctic sea ice melt years are often associated with heavy sea ice in winter-spring, which is favorable for the occurrence of Arctic anticyclonic circulation anomaly and lead to a positive SAT anomaly in the Arctic. The Arctic warming not only strengthens polar zonal westerly winds by increasing local baroclinicity, but also weakens zonal winds in mid-latitude through a reduction meridional temperature gradient. It may contribute to the Arctic anticyclonic anomalies enhancement, and then induces a wave train southeastward propagating into the mid-low latitudes. This configuration of atmospheric circulation anomalies provides favorable conditions for the SAT variations over Eurasia. [ABSTRACT FROM AUTHOR]