What derives the process of atlantification in Arctic Ocean

What derives the process of atlantification in Arctic Ocean

Subject :Environment

Section: Climate Change

Context:

• New research by an international team of scientists explains what’s behind a stalled trend in Arctic Ocean sea ice loss since 2007.

Details:

• The findings indicate that stronger declines in sea ice will occur when an atmospheric feature known as the Arctic dipole reverses itself in its recurring cycle.
• The analysis helps explain how North Atlantic water influences Arctic Ocean climate, a process scientists call “Atlantification.”

Atlantification of Arctic ocean:

• Atlantification is the increasing influence of Atlantic water in the Arctic. Warmer and saltier Atlantic water is extending its reach northward into the Arctic Ocean.
• This change in the Arctic climate is most prominent in the Barents Sea, a shallow shelf sea north of Scandinavia, where sea-ice is disappearing faster than in any other Arctic region, impacting the local and global ecosystem.

Key findings of the research:

• Analysis shows that the Arctic dipole alternates in an approximately 15-year cycle and that the system is probably at the end of the present regime.
• In the Arctic dipole’s present “positive” regime, high pressure is centered over the Canadian sector of the Arctic and produces clockwise winds.
• Low pressure is centered over the Siberian Arctic and features counterclockwise winds. This wind pattern drives upper ocean currents, with year-round effects on:
  • regional air temperatures,
  • atmosphere-ice-ocean heat exchanges,
  • sea-ice drift and exports, and
  • ecological consequences.
• Water exchanges between the Nordic seas and the Arctic Ocean are critically important for the state of the Arctic climate system” and sea ice decline is “a true indicator of climate change.”
• Ocean responses to wind pattern:
  • Decreased flow from the Atlantic Ocean into the Arctic Ocean through the Fram Strait east of Greenland, along with increased Atlantic flow into the Barents Sea, located north of Norway and western Russia.
  • These alternating changes in the Fram Strait and the Barents Sea are referred to as a “switchgear mechanism” caused by the Arctic dipole regimes. This mechanism can lead to potentially more suitable living conditions for sub-Arctic boreal species near the eastern part of the Eurasian Basin, relative to its western part.
  • Counterclockwise winds from the low-pressure region under the current positive Arctic dipole regime drive freshwater from Siberian rivers into the Canadian sector of the Arctic Ocean.
  • This westward movement of freshwater from 2007 to 2021 helped slow the overall loss of sea ice in the Arctic compared to 1992 through 2006. The freshwater layer’s depth increased, making it too thick and stable to mix with the heavier saltwater below. The thick layer of freshwater prevents the warmer saltwater from melting sea ice from the bottom.

Fram strait:

• The Fram Strait is the passage between Greenland and Svalbard.
• The Greenland and Norwegian Seas lie south of Fram Strait, while the Nansen Basin of the Arctic Ocean lies to the north.
• Fram Strait is noted for being the only deep connection between the Arctic Ocean and the World Oceans.
• The dominant oceanographic features of the region are the West Spitsbergen Current on the east side of the strait and the East Greenland Current on the west.