Climatic Overview of NAFO Subarea 1, 1991–2000

M. Stein

Institut für Seefischerei, Palmaille 9, D-22767 Hamburg
Federal Republic of Germany

Publication (Upload) date: 24 September 2004 (updated 15 April 2010)

STEIN, M. 2004. Climatic Overview of NAFO Subarea 1, 1991–2000. J. Northw. Atl. Fish. Sci., 34: 29-41. https://doi.org/10.2960/J.v34.m474

Abstract

Based on climatological data on air temperatures, sea ice cover, as well as on subsurface oceanographic time series and historic data from World Ocean Data Centre A (WDC-A), this paper analyses the climatic conditions off West Greenland during the decade of the 1990s and compares them with previous decades. The 1990s was a decade of extremes. The North Atlantic Oscillation (NAO) index flipped from one of its most positive values in winter 1995 to one of its most negative the following winter and reached a high level again during the last winter of the decade. Air temperatures at Nuuk tended to follow these extremes, e.g. during the high NAO Index in the early-1990s, there were very cold air temperatures at West Greenland. Approximately 50% of the variance in winter temperatures at Nuuk can be explained by air pressure changes over the North Atlantic. Nuuk air temperatures are shown to be representative of the climatic variability over the west coast of West Greenland from Cape Farewell in the south to Egedesminde in the Disko Bight area. There is significant correlation between the area-weighted mean bottom water temperature index for the German groundfish survey area off East and West Greenland and the autumn time series data from Fyllas Bank station 4 for the corresponding depth layers 0–200 m and 200–400 m. Accordingly, the subsurface oceanic variability measured at this slope station can be used as proxy for subsurface ocean variability off West Greenland. Surface layer cooling during the early-1990s was accompanied by decreasing salinities in the upper 400 m at the slope of Fyllas Bank, perhaps due to the heavy sea-ice conditions during 1992–93. There is evidence of low surface salinities (<33.0) during summer and autumn at Fyllas Bank station 4. These low salinities are not found during spring. This low saline water during summer and autumn off West Greenland is possibly derived from the Arctic freshwater supply that passes along East Greenland. The presence of Irminger Water (4°C <<6°C, 34.95 <S <35.1) at the slope off Fyllas Bank is mapped using WDC-A data from 1946 to 1999. It is shown that this water mass, mostly found at depths between 400 and 800 m, arrives in pulses and was present during several years in the second half of the 20th century. There were, however, major periods (1955–62 and 1973–81) when Irminger Water was not observed at Fyllas Bank station 4.

Key words: North Atlantic Oscillation (NAO index), air temperatures, ocean temperatures, salinity, Irminger Water.

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