Impact of model resolution on the representation on the air‐sea interaction associated with the North Water Polynya

The North Water polynya (NOW), one of the largest and most productive of Arctic polynyas, is situated just downwind of Smith Sound, the southern terminus of Nares Strait. The high topography along the narrow strait results in the common occurrence of high speed northerly flow that is accelerated through Smith Sound. The resulting divergence of the surface wind field contributes to the formation of the polynya. Within the NOW, the combination of high winds, cold and dry Arctic air as well as reduced ice cover can result in the transfer of heat, moisture and momentum from the ocean to the atmosphere. Much of our knowledge of the air‐sea interaction over the NOW comes from atmospheric models, many of which have horizontal resolutions greater than 75 km. As such there is concern that they may under‐represent the characteristics of the flow in the region impacting the representation of the resulting air‐sea interaction. Here we use a set of atmospheric analyses with a common lineage but with horizontal resolutions that range from ~75 km to ~9 km to characterize this interaction. We show that increasing model resolution leads to an improved representation of the kinematics of the flow along the strait. However details of the thermodynamics are more nuanced and as a result, the intensity of the air‐sea interaction over the NOW does not simply increase with increasing resolution. The results suggest a horizontal atmospheric model resolution less than ~30 km is needed to represent the air‐sea interaction over the NOW and that a re‐evaluation of previous modeling efforts in the region is needed.