Near-surface atmosphere, ocean, and sea ice properties and processes are spatially variable, making the ocean and sea ice response to melt fluxes spatially variable. Surface runoff, ice shelf basal melt, and icebergs affect ocean stability and sea ice processes. It is important to understand the effects of this assumption on future climate projections, so as to interpret them appropriately.Īlmost all mass loss from the Antarctic continent, with the exception of sublimation, enters the ocean as meltwater. Coupling a dynamic ice sheet model with an ESM to realistically capture the changing mass loss rate is technically complex, and most ESMs therefore share the assumption that the rate of mass loss is temporally constant. 2018) and is likely to continue to increase ( Timmermann and Hellmer 2013). Mass loss from Antarctica has increased in recent years ( Rignot et al. An example of this is the rate at which ice mass is lost from Antarctica, which is the focus of this study. In addition to calculating the likely future climate, ESMs are excellent tools for investigating the sensitivity of the climate system to specific processes, providing insights useful for understanding responses to future change. These insights are helpful for interpretation of climate simulations that assume constant mass loss rates and demonstrate the importance of representing increasing melt rates for both ice shelves and icebergs.Įarth system models (ESMs) link physical processes on land, sea ice, ocean, and atmosphere and the feedbacks between them. We show that as meltwater fluxes increase, snowfall becomes more likely at lower latitudes and Antarctic Circumpolar Current transport declines. We find similar surface temperature and salinity responses to increasing meltwater fluxes from ice shelves and icebergs, but midlayer waters warm to greater depths and farther north when ice shelf melt is present. In our experiments, the mixed layer around the Antarctic coast deepens in response to rising ice shelf meltwater and shallows in response to stratification driven by iceberg melt. ![]() We present results from simulated scenarios of increasing meltwater fluxes and show that these drive sea ice increases and, for increasing ice shelf melt, a decline in Antarctic Bottom Water formation. This configuration makes it appropriate to revisit how increasing melt fluxes influence ocean and sea ice and to assess whether responses to melt from ice shelves and icebergs are distinguishable. The coupled atmosphere–land–ocean–sea ice model, HadGEM3-GC3.1, includes a realistic spatial distribution of coastal melt fluxes, a new ice shelf cavity parameterization, and explicit representation of icebergs. Numerous studies have investigated sea ice and ocean sensitivity to this assumption and reached different conclusions, possibly due to different representations of melt fluxes. Mass loss from the Antarctic continent is increasing however, climate models either assume a constant mass loss rate or return snowfall over land to the ocean to maintain equilibrium.
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