On the impact of high-resolution, high-frequency meteorological forcing on Denmark Strait ocean circulation

摘要

This paper quantifies and discusses the impact of high-resolution, high-frequency atmospheric forcing on the ocean circulation in the vicinity of the Denmark Strait. The approach is to force a 2 km resolution regional ocean circulation model with atmospheric states from reanalysis products that have different spatial and temporal resolutions. We use the National Center for Environmental Prediction global reanalysis data (2.5 deg resolution, 6-hourly output) and a specially configured regional atmospheric model (12 km resolution, hourly output). The focus is on the month-long period in winter 2007 during the Greenland Flow Distortion Experiment. Diagnostics of upper-ocean currents and mixing are sensitive to the small-scale variability in the high-resolution regional atmospheric model. The hydrographic state of the ocean model is insensitive over the month-long experiments, however. Both sea ice and the fluxes of volume, heat, and freshwater across the east Greenland shelf break and through the Denmark Strait show a moderate response to the high-resolution atmospheric forcing. The synoptic-scale atmospheric state has a large role in controlling sea ice too, while internal ocean dynamics is the dominant factor controlling the flux diagnostics. It is the high spatial resolution, not the temporal resolution, that causes these effects, with O(10 km)-scale features being most important. The sea-level wind field is responsible, with the other atmospheric fields playing relatively minor roles.