Observed current in the Fugløya-Bear Island region is predominantly barotropic, and reveals large fluctuations in both current speed and lateral structure (Ingvaldsen et al., 2002; 2004). In general, the current is wide and slow during summer and fast, with possibly several cores, during winter. The volume transport resembles the velocity field and varies with season due to close coupling with regional atmospheric pressure. Numerical models forced with wind predict that southwesterly winds, which is predominant during winter, accelerates flow of Atlantic Water into the Barents Sea; whereas, weaker and more fluctuating northeasterly winds, common during summer, slows transport. The same conclusion is reached using current measurements in the exit area of northeast Barents Sea. Since 1997, monitoring transport of Atlantic Water into the Barents Sea indicates highly variable net transport that averages 2 Sv (Sv = 106 m3s-1). The average transport of Atlantic Water into the Barents Sea during 1997-2007 is 2.2 Sv during winter and 1.8 Sv during summer. During years in which the Barents Sea changes from cold to warm marine climate, the seasonal cycle can be inverted. Moreover, an annual event of northerly wind causes a pronounced spring minimum inflow to the western Barents Sea; at times even an outward flow.
Strong tidal currents, peaking at 80-100 cm/s in spring, are present on Svalbardbanken (Gjevik et al., 1994). In this area, the tide induces a residual current that forms an anti-cyclonic eddy between Bear Island and Hopen. The largest tidal amplitudes are found along the coast of Finnmark in Norway and Kola in Russia, where the amplitude extends up to 1.3 m. In the Hopen Trench there is a main amphidromic system (i.e. the tidal amplitude in the centre of the amphidromic system is approximately zero).
Heat transport into the Barents Sea is formed by a combination of volume and temperature of inflowing water masses, although these two factors are not necessarily linked. The reason is that while temperature of inflowing water depends on temperatures upstream in the Norwegian Sea, the volume flux depends mainly on the local wind field. This signals the importance of measuring both volume transport and temperature, since volume flux is essential to transport zooplankton, fish eggs, and larvae into the Barents Sea.
Surface drift experiments have demonstrated large numbers of mesoscale eddies in the Barents Sea, particularly in the western region. Small eddies are generated both in the frontal area between Atlantic and Coastal Currents and along the shear zone between waters flowing in and out of the Bear Island Trench. Most of these eddies are limited in time and space, but may last for a month. Large eddies, generated by the local topography, have also been observed; examples are cyclonic (counter-clockwise) eddies at Ingøy Deep, and anti-cyclonic (clockwise) eddies at Central and Great Banks. Eddies prolong local residence time for organisms passively advected with currents, such as plankton and fish larvae.
Monthly wind-driven and total volume fluxes through sections crossing the main currents of the Barents Sea were calculated with a numerical model for 1971-2000. Seasonal variations in the wind-driven and total fluxes are shown in Figure 2.3.4 and Figure 2.3.5, respectively.
Despite the fact that these curves have different shapes for different sections, the common features are easily noted. As a rule, the seasonal minimum is April-June for total flux and May-June for wind-driven flux, while the seasonal maximum is November-January for total flux and January-March for wind-driven flux.
