Publication Date:
2017-11-01
Description:
We consider the volume budget of the Arctic sea ice in the CMIP5 global coupled model HadGEM2-ES, and evaluate how the budget components evolve during the 21st century under a range of different forcing scenarios. As the climate warms and the ice cover declines, the Arctic sea ice processes that change the most in HadGEM2-ES are summer melting at the top surface of the ice, and basal melting due to extra heat from the warming ocean. However, the declining ice cover affects how much impact these changes have on the ice volume budget, where the biggest contribution to Arctic ice decline is the reduction in the total amount of basal ice formation during the autumn and early winter. This highlights the importance of taking the declining ice area into account when evaluating projected changes in the sea ice budget, especially if comparing models with very different rates of decline. Changes in the volume budget during the 21st century have a distinctive seasonal cycle, with processes contributing to ice decline occurring in May/June and September to November. During July and August the total amount of sea ice melt decreases, due to the reducing ice cover. The choice of forcing scenario affects the rate of ice decline and the timing and magnitude of changes in the volume budget components, but for the HadGEM2-ES model and for the range of scenarios considered for CMIP5, the mean changes in the volume budget depend on the evolving ice area, and are independent of the speed at which the ice cover declines.
Print ISSN:
1994-0432
Electronic ISSN:
1994-0440
Topics:
Geography
,
Geosciences
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