Oceanic response to midlatitude Rossby waves aloft and its feedback in the lower atmosphere in winter Northern Hemisphere

Abstract

Midlatitude Rossby waves substantiated in the upper tropospheric (300–200 hPa) potential vorticity field exert significant influences on surface conditions. The physical changes associated with the propagation of Rossby waves are investigated from a climatological perspective, particularly over the oceans. Detailed analysis quantitatively shows that the passing of positive Rossby waves with cyclonic vortexes increases net shortwave and longwave radiation over an ocean's surface by promoting a clearer sky condition. Further, the reduced humidity and temperature above the sea surface increases latent and sensible heat fluxes. The increased latent and sensible heat fluxes, in turn, induce secondary atmospheric circulation, characterized by anticyclonic and divergent motion in the lower atmospheric layer above the sea surface. Although the increased latent and sensible heat fluxes may change sea surface temperatures, the complexity of ocean dynamics with complicated land–ocean configurations and the mismatch of the temporal and spatial scales of atmospheric and oceanic motions smears the footprint of Rossby waves.