Impact of Sea Ice Reduction in the Barents and Kara Seas on the Variation of the East Asian Trough in Late Winter

Abstract Using the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim) dataset and Specified Chemistry Whole Atmosphere Community Climate Model (WACCM-SC), impacts of sea ice reduction in Barents–Kara Seas (BKS) on East Asian trough (EAT) late winter are investigated. Results from both data simulations show that BKS leads to a deepened EAT winter, especially February, while axis tilt is not sensitive reduction. Further analysis shows influences through tropospheric stratospheric pathways. For pathway, results linearized barotropic model Rossby wave ray tracing reveal long trains stimulated by loss propagate downstream North Pacific, strengthening EAT. upward planetary waves enhanced shift subpolar westerlies near tropopause southward. With critical lines displaced equatorward, poleward transient eddies break at lower latitudes, shifting eddy momentum deposit throughout troposphere equatorward. Tropospheric maintained also shifted southward, inducing cyclonic anomalies over Pacific deepening winter. Nudging experiments pathway only contributes around 29.7% February induced loss, remaining 70.3% caused stratosphere–troposphere coupling.