The linked reference and two related articles indicate that since 1997 the Beaufort Gyre (associated with the high pressure atmospheric condition shown in the first image) has accumulated an anomalously high amount of ocean heat content within the relatively fresh water accumulated in the gyre; which, could rapidly be released into the Arctic Ocean during sustained atmospheric conditions with a low pressure system over the Beaufort Gyre (see the second image). Not only would such a relatively rapid release of relatively warm relatively fresh water from the Beaufort Gyre slow down the MOC (which would accelerated warming of the tropical sea surface temperatures) but would also likely result in a relatively abrupt reduction of Arctic sea ice as discussed in the second linked article from 2019.
Mary-Louise Timmermans John Toole and Richard Krishfield (29 Aug 2018), "Warming of the interior Arctic Ocean linked to sea ice losses at the basin margins", Science Advances, Vol. 4, no. 8, eaat6773, DOI: 10.1126/sciadv.aat6773
https://advances.sciencemag.org/content/4/8/eaat6773AbstractArctic 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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Title: "Signs of Big Change in the Arctic - A once-predictable system shifts out of balance"
https://www.whoi.edu/oceanus/feature/signs-of-big-changes-in-the-arctic/Extract: "For at least half a century and probably longer, the climate in the Arctic has run like a clock. As reliably as a pendulum, it has oscillated every five to seven years between two distinct self-regulating phases that shift the region’s winds, ice, currents, and other conditions.
But in a new study, scientists say the system has been stuck in one phase since 1997. The monkey wrench that’s jamming the works, they suspect, may be warming temperatures that are accelerating the melting of the Greenland Ice Sheet.
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When ice melts, it can no longer play the important role of reflecting sunlight. Instead, the melting gives the sun unfettered access to the open water, allowing the ocean to absorb more heat.
As that heat diffuses upward over time, it stalls the growth of the sea ice during the winter in the region, said Toole. “And, if the deeper, warmer water starts mixing more vigorously with the cold water above it, we will see even more sea ice thinning during the summer.”"
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Title: "A ‘Ticking Time Bomb’ in the Arctic - Waters are warming beneath the ocean's sea ice"
https://www.whoi.edu/oceanus/feature/a-ticking-time-bomb-in-the-arctic/Extract: "When it comes to the ocean, deeper usually means colder. But there are exceptions. In the Arctic Ocean, for example, a warm layer of water is trapped 150 feet under the ocean’s chunky ice floes by a ceiling of cold fresh water near the surface. The cold layer insulates the sea ice from the warmer waters below.
In a 2018 study, scientists have found that the amount of heat in the trapped warm layer in the Beaufort Gyre, a major Arctic Ocean circulation system north of Alaska, has doubled over the past 30 years. And, if the temperatures continue to spike, it could eventually spell trouble for the ice above.
“At some point, the heat from this layer is going to have to come up to the surface, and it’s going to impact the ice,” said John Toole, a scientist at Woods Hole Oceanographic Institution (WHOI) and co-author of the study. “It’s a ticking time bomb.”
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The study is yet another case in point of why melting Arctic sea ice is a problem: When ice melts, it can no longer play the important role of reflecting sunlight. Instead, the melting gives the sun unfettered access to the open water, allowing the ocean to absorb more heat.
As that heat diffuses upward over time, it stalls the growth of the sea ice during the winter in the region, said Toole. “And, if the deeper, warmer water starts mixing more vigorously with the cold water above it, we will see even more sea ice thinning during the summer.”"
