Tropical forcing of Circumpolar Deep Water Inflow and outletglacier thinning in the Amundsen Sea Embayment, West Antarctica

first_imgOutlet glaciers draining the Antarctic ice sheet into the Amundsen Sea Embayment (ASE)have accelerated in recent decades, most likely as a result of increased melting of their ice-shelf terminiby warm Circumpolar Deep Water (CDW). An ocean model forced with climate reanalysis data showsthat, beginning in the early 1990s, an increase in westerly wind stress near the continental shelf edgedrove an increase in CDWinflow onto the shelf. The change in local wind stress occurred predominantlyin fall and early winter, associated with anomalous high sea-level pressure (SLP) to the north of the ASEand an increase in sea surface temperature (SST) in the central tropical Pacific. The SLP change isassociated with geopotential height anomalies in the middle and upper troposphere, characteristic of astationary Rossby wave response to tropical SST forcing, rather than with changes in the zonallysymmetric circulation. Tropical Pacific warming similar to that of the 1990s occurred in the 1940s, andthus is a candidate for initiating the current period of ASE glacier retreat.last_img

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