Storm-Driven Mixing and Potential Impact on the Arctic Ocean
Abstract
Observations of the ocean, atmosphere, and ice made by Ice-Ocean Environmental Buoys indicate that mixing events reaching the depth of the halocline have occurred in various regions in the Arctic Ocean. This analysis suggests that these mixing events were mechanically forced by intense storms moving across the buoy sites. In this study, the authors analyzed these mixing events in the context of storm developments that occurred in the Beaufort Sea and in the general area just north of Fram Strait, two areas with quite different hydrographic structures. The Beaufort Sea is strongly influenced by inflow of Pacific water through the Bering Strait, while the area north of Fram Strait is directly affected by the inflow of warm and salty North Atlantic water. These analyses of the basin-wide evolution of the surface pressure and geostrophic wind fields indicate that the characteristics of the storms could be very different. The buoy-observed mixing occurred only in the spring and winter seasons when the stratification was relatively weak. This indicates the importance of stratification, although the mixing itself was mechanically driven. The authors also analyze the distribution of storms, both the long-term climatology and the patterns for each year in the past 2 decades. The frequency of storms is also shown to be correlated (but not strongly) to Arctic Oscillation indices. This study indicates that the formation of new ice that leads to brine rejection is unlikely the mechanism that results in the type of mixing that could overturn the halocline. On the other hand, synoptic-scale storms can force mixing deep enough to the halocline and thermocline layers. Despite a very stable stratification associated with the Arctic halocline, the warm subsurface thermocline water is not always insulated from the mixed layer. (23 figures, 28 refs.)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 09, 2004
- Accession Number
- ADA423407
Entities
People
- David Walsh
- Jiayan Yang
- Josefino Comiso
- Richard Krishfield
- Susumu Honjo
Organizations
- United States Naval Research Laboratory