Abiotic components

Meteorological conditions - Atmospheric pressure and wind field

Thu, 03 Dec 2009 15:32:38 +0000

In winter 2007/2008, a low-pressure trough related to the Icelandic Low dominated the northern North Atlantic, the Nordic Seas and stretched deep into the Barents Sea (Figure 4.2.1). Large negative air pressure anomalies (-4 - -5 mb) were spread over the Norwegian and northern Barents Seas. The southern part of the Barents Sea were dominated by a bit smaller negative anomalies (-3 - -4 mb). Such an air pressure pattern would have strengthened the southwesterly winds and increased transport of warm air and water in the southern Barents Sea.

Meteorological conditions - Air temperatures

Thu, 03 Dec 2009 15:34:21 +0000

Air temperature data were taken from http://nomad2.ncep.noaa.gov/ and averaged over the western (70-76°N, 15-35°E) and eastern (69-77ºN, 35-55ºE) parts of the sea. During winter and spring, the air temperature was warmer than normal, with maximum positive anomalies (6.0-7.0 °C) in the eastern Barents Sea in February and March. In April-September, the air temperature was generally close to the long-term means, with prevalence of small negative anomalies (<0.5 °C).

Oceanographic conditions - Temperature at the surface, 100 m and in the bottom layer

Thu, 03 Dec 2009 15:37:55 +0000

Sea surface temperature (SST) data were taken from http://iridl.ldeo.columbia.edu/ and averaged over the Bear Island – Svalbard area (74-79ºN, 08-25ºE), central (71-74ºN, 20-40ºE) and southeastern Barents Sea (69-73ºN, 42-55ºE). The SST shows much of the same variations as the air temperatures. During winter, over most of the Barents Sea, SST was higher-than-normal, with maximum anomalies of 1.2-1.4 °C in the eastern areas. During spring, positive anomalies of SST decreased to 0.3-0.7 °C in the eastern Barents Sea whereas negative anomalies of SST (0.2-0.3 °C) dominated in the western sea.

Oceanographic conditions - Currents and transports

Thu, 03 Dec 2009 15:42:56 +0000

The temperature and the volume flux of the inflowing Atlantic Water in the Fugløya-Bear Island Section do not always vary in phase. The temperature is mainly determined by variations upstream in the Norwegian Sea, while the volume flux to a large degree varies with the wind conditions in the western Barents Sea. The volume flux varies with periods of several years, and was significantly lower during 1997-2002 than during 2003-2006 (Figure 4.2.10). The year of 2006 was a special year as the volume flux both had a maximum (in winter 2006) and minimum (in fall 2006).

Oceanographic conditions - Ice conditions

Thu, 03 Dec 2009 15:45:13 +0000

Throughout most of the year of 2008, the sea ice extent was less than normal, but more than in 2007. In comparison with the previous year, the ice coverage (expressed as a percentage of the sea area) was 2-6 % more in January-March and twice as much by June. In May, a polynya started to form south of the Franz Josef Land archipelago and in July the ice massif was finally broken. Come September, the area near Franz Josef Land was ice-free and the main ice massif was in the north-western Barents Sea near the east coast of the Spitsbergen archipelago.

Oceanographic conditions - Chemical conditions

Thu, 03 Dec 2009 15:46:46 +0000

Since 2002, there has been a gradual increase in oxygen saturation of the bottom layers in the southern Barents Sea, – and this continued in 2008. The oxygen saturation anomaly in the bottom layer was 0.65 % during the first nine months of 2008, while during the same period in 2007 the anomaly was 0.14 % (Figure 4.2.13).

Oceanographic conditions - Expected situation

Thu, 03 Dec 2009 15:48:21 +0000

The ocean has a "long memory" compared to the atmosphere, and it is therefore feasible, at least a priori, to realistically predict ocean temperature much further ahead than the typical weather forecast. The prediction is complicated by the variation being governed by processes of both external and local origin operating on different time scales. Thus, both slowly moving advective propagation and rapid barotropic responses due to large-scale changes in air pressure must be considered.