Investigating The Impact Of Sea Ice Concentration Extremes On Atmospheric Moisture Transport And Low-Level Winds Over Greenland And Surrounding Seas

Abstract:

Two of the most striking changes occurring in the Arctic over the past decade are the decline in sea ice extent and increased mass loss from the Greenland ice sheet (GrIS). From an Arctic system perspective, the physical linkages between sea ice extent and the GrIS mass loss remain to be explored with the results from previous research pointing to a correlation between these two processes. In this study, we assess the relationship between sea ice concentration variability and its extremes and both local and large-scale forcing of ocean heat and moisture advection on the GrIS. To this aim, we employ a variety of tools and datasets such as the outputs of a regional climate model (Modèle Atmosphérique Régional, MAR), surface wind observations, and reanalysis data. In particular, we test the hypothesis that sea ice extent variability influences GrIS surface energy and mass balance through oceanic heat advection and focus on understanding the physical processes involved. Using the outputs of a 35-year (1979–2014) simulation from the MAR model, we examine the spatiotemporal co-variability of the heat and moisture fluxes over ocean (divided regions based on latitude) with sea ice concentration (SIC) against the same fluxes over the GrIS during the five highest and lowest SIC years, as estimated from satellite and reanalysis datasets. We then report a comparative analysis of simulated changes in wind for high and low SIC years against weather-station observations to determine surface wind height—in this case, katabatic wind height—relative to the depth of moisture transport in the boundary layer. Lastly, we focus on the influence of large-scale upper level circulation, such as 500-hPa eddy heat fluxes and the known modes of atmospheric variability (e.g. the Greenland Blocking Index.)