Density-dependent variations of the along-isobath flow in the East Greenland Current from Fram Strait to Denmark Strait



[1] The East Greenland Current (EGC) dynamically connects the Arctic Ocean to the North Atlantic on the western side of the Nordic Seas. Observations show that the speed of the EGC considerably varies along the East Greenland Slope (EGS). Here it is shown, using current meter data reported in the literature and climatological hydrographic fields, that velocity and transport variations along the EGS are supported by the cross-isobath component of the density-dependent geostrophic flow relative to the bottom. The relative flow impinging on (leaving) the EGS in a northern (southern) limb of the cyclonic circulation in the Nordic Seas strengthens (weakens) the along-isobath bottom geostrophic flow. Variations of the latter are clearly associated with along-isobath bottom density gradients. Current observations indicate an increase of the along-isobath bottom velocity from 79°N to 75°N equal to about 9 and 10 cm s−1 on the upper (1000 m isobath) and lower (2000 m isobath) EGS, respectively. Corresponding estimates based on bottom density distribution along the 1000 and 2000 m isobaths are grossly consistent with the observations given above though we obtain a higher increase (13 cm s−1) at 1000 m and lower increase (6 cm s−1) at 2000 m. Considering the variability of the system and the poor resolution of the observations we find this to be a very convincing result, demonstrating the power of the geostrophic approximation for such estimates.