Ongoing ocean climate observations
ICES Working Group on Oceanic Hydrography (WGOH) is the custodian of some of the longest-running time-series of ocean observations, many of which now extend more than forty years.
The group meets annually to review the oceanographic conditions in the North Atlantic, publishing the findings in ICES Report on Ocean Climate. After meeting in April, their joint analysis has strengthened individual organizational efforts to provide the following highlights for the North Atlantic in 2021.
Salinity
The record low salinities that were first observed in the subpolar gyre between 2016–2017 have continued to spread out -within expected timelines- along the main circulation pathways, both northwards into the North Sea, Nordic Seas, Barents Sea, and Fram Strait and southwards into the subtropical gyre.
Low salinity anomalies are now also apparent deeper in the water column, meaning that this is no longer an exclusive surface feature.
Salinities in the subpolar gyre itself and the immediate downstream pathways, for example Atlantic Water in the Faroe Current, Faroe Bank Channel, and deep regions west of Scotland, have increased to near average.
Record low salinity in the surface waters of the Bay of Biscay and Iberian coast, the Gulf of Cadiz, and the Canaries is
changing water column stratification (i.e. increasing the buoyancy anomaly). For example, in the Bay of Biscay and Iberian coast, the salinity of the upper 500 m is the lowest observed in approximately the last three decades.
Temperatures
Temperatures across the North Atlantic surface water and the inflowing Atlantic Water to the Norwegian Sea and the Barents Sea remain close to the long-term average. However, the deep waters in the Nordic Seas and associated overflow branches have continued to warm. In some regions, for example, the Greenland Sea between 700–2000 m, this warming appears to have slowed or even stopped. Record warming was observed on the continental shelves of the western North Atlantic in 2021.
Near-bed ocean temperatures were substantially above normal across the region, including record highs in the northern Gulf of St. Lawrence, off southern Newfoundland, and across the Northeast US Shelf. The area of sea ice in the Barents Sea was much lower in 2021 compared to previous years. The lowest ever volume of sea ice was recorded in the Gulf of St. Lawrence since records began in 1969.
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(PM ICES, gekürzt)
The full article can be found at ices.dk