The Rossby radius in the Arctic Ocean

The first (and second) baroclinic deformation (or Rossby) radii are presented north of similar to 60 degrees N, focusing on deep basins and shelf seas in the high Arctic Ocean, the Nordic seas, Baffin Bay, Hudson Bay and the Canadian Arctic Archipelago, derived from climatological ocean data. In the high Arctic Ocean, the first Rossby radius increases from similar to 5 km in the Nansen Basin to similar to 15 km in the central Canadian Basin. In the shelf seas and elsewhere, values are low (1-7 km), reflecting weak density stratification, shallow water, or both. Seasonality strongly impacts the Rossby radius only in shallow seas, where winter homogenization of the water column can reduce it to below 1 km. Greater detail is seen in the output from an ice-ocean general circulation model, of higher resolution than the climatology. To assess the impact of secular variability, 10 years (2003-2012) of hydrographic stations along 150 degrees Win the Beaufort Gyre are also analysed. The first-mode Rossby radius increases over this period by similar to 20 %. Finally, we review the observed scales of Arctic Ocean eddies.