Modeling Antarctic ice shelf responses to future climate changes and impacts on the ocean

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Kusahara, K, Hasumi, H
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell Publishing, Inc. 2013
• Subjects: Earth Sciences; Atmospheric Sciences; Climate Change Processes; Antarctic; Bellingshausen Sea; The Antarctic; Weddell; Weddell Sea; Antarc*; Ice Shelf; Ice Shelves; Sea ice
• Online Access: https://doi.org/10.1002/jgrc.20166; http://ecite.utas.edu.au/109275

We investigate basal melting of all Antarctic ice shelves by a circumpolar iceshelf-sea ice-ocean coupled model and estimate the total basal melting of 770944 Gt/yrunder present-day climate conditions. We present a comparison of the basal melting withprevious observational and modeling estimates for each ice shelf. Heat sources for basalmelting are largely different among the ice shelves. Sensitivities of the basal melting tosurface air warming and to enhanced westerly winds over the Antarctic CircumpolarCurrent are investigated from a series of numerical experiments. In this model the totalbasal melting strongly depends on the surface air warming but is hardly affected by thechange of westerly winds. The magnitude of the basal melting response to the warmingvaries widely from one ice shelf to another. The largest response is found at ice shelves inthe Bellingshausen Sea, followed by those in the Eastern Weddell Sea and the Indiansector. These increases of basal melting are caused by increases of Circumpolar DeepWater and/or Antarctic Surface Water into ice shelf cavities. By contrast, basal melting ofice shelves in the Ross and Weddell Seas is insensitive to the surface air warming,because even in the warming experiments there is high sea ice production at the front ofthe ice shelves that keeps the water temperature to the surface freezing point. Weakeningof the thermohaline circulation driven by Antarctic dense water formation under warmingclimate conditions is enhanced by basal melting of ice shelves.