Thursday, 30 August 2018

Evidence that there is enough energy to melt interior Arctic ice from below


This confirms everything that we know about the Arctic ice from oobservations - that it is melting from below and this process does not stop with the ending of the melt season

Enough Heat to Melt Interior Arctic Ocean Ice is Building Beneath the Surface



Robert Fanney

A new study shows that the excess heat developed in newly ice free zones is being transported beneath the central ice. This heat is sequestered in a layer beneath the surface. But it contains enough energy to keep large regions of the Beaufort Sea ice free during most months if mixed, according to the new research.


Archived’ heat has reached deep into the Arctic interior, researchers say

By Jim Shelton
August 29, 2018

A heat map of the Arctic interior
Arctic sea ice isn’t just threatened by the melting of ice around its edges, a new study has found: Warmer water that originated hundreds of miles away has penetrated deep into the interior of the Arctic.

That “archived” heat, currently trapped below the surface, has the potential to melt the region’s entire sea-ice pack if it reaches the surface, researchers say.
The study appears online Aug. 29 in the journal Science Advances.

We document a striking ocean warming in one of the main basins of the interior Arctic Ocean, the Canadian Basin,” said lead author Mary-Louise Timmermans, a professor of geology and geophysics at Yale University.

The upper ocean in the Canadian Basin has seen a two-fold increase in heat content over the past 30 years, the researchers said. They traced the source to waters hundreds of miles to the south, where reduced sea ice has left the surface ocean more exposed to summer solar warming. In turn, Arctic winds are driving the warmer water north, but below the surface waters.

This means the effects of sea-ice loss are not limited to the ice-free regions themselves, but also lead to increased heat accumulation in the interior of the Arctic Ocean that can have climate effects well beyond the summer season,” Timmermans said. “Presently this heat is trapped below the surface layer. Should it be mixed up to the surface, there is enough heat to entirely melt the sea-ice pack that covers this region for most of the year.”

The co-authors of the study are John Toole and Richard Krishfield of the Woods Hole Oceanographic Institution.

The National Science Foundation Division of Polar Programs provided support for the research.


Abstract

Arctic Ocean measurements reveal a near doubling of ocean heat content relative to the freezing temperature in the Beaufort Gyre halocline over the past three decades (1987–2017). This warming is linked to anomalous solar heating of surface waters in the northern Chukchi Sea, a main entryway for halocline waters to join the interior Beaufort Gyre. Summer solar heat absorption by the surface waters has increased fivefold over the same time period, chiefly because of reduced sea ice coverage. It is shown that the solar heating, considered together with subduction rates of surface water in this region, is sufficient to account for the observed halocline warming. Heat absorption at the basin margins and its subsequent accumulation in the ocean interior, therefore, have consequences for Beaufort Gyre sea ice beyond the summer season.

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