Woods Hole Oceanographic Institution

Steven R. Jayne

»Sc.D. Thesis
»Recirculation gyres in a beta-plane jet
»Forcing and sampling of ocean models
»Thermohaline circulation - sea ice feedback
»Recirculation forced by an unstable jet
»Tidal dissipation over rough topography
»Dynamics of ocean heat transport variability
»Deep ocean currents from GRACE
»Estimates of tidally-driven mixing
»Millennial climate variability
»Oceanic eddy heat transport
»Ocean heat content from GRACE
»Tidally-driven mixing in an ocean model
»Ocean bathymetry and Earth's climate
»Bathymetry from space
»Subtropical mode water during KESS
»North Atlantic Ocean circulation from GRACE
»Subtropical mode water in the Kuroshio Extension
»Tidal mixing during the Last Glacial Maximum
»Kuroshio northern recirculation gyre
»Bottom pressure in KESS and GRACE
»Ocean model metrics
»Abyssal mixing in CCSM
»Kuroshio Extension jet and transport
»The Morphology of Steve

S. R. Jayne and J. Marotzke , A destabilizing thermohaline circulation - atmosphere - sea ice feedback , Journal of Climate, 1999

Some of the interactions and feedbacks between the atmosphere, thermohaline circulation, and sea ice are illustrated using a simple process model. A simplified version of the annual-mean coupled ocean–atmosphere box model of Nakamura, Stone, and Marotzke is modified to include a parameterization of sea ice. The model includes the thermodynamic effects of sea ice and allows for variable coverage. It is found that the addition of sea ice introduces feedbacks that have a destabilizing influence on the thermohaline circulation: Sea ice insulates the ocean from the atmosphere, creating colder air temperatures at high latitudes, which cause larger atmospheric eddy heat and moisture transports and weaker oceanic heat transports. These in turn lead to thicker ice coverage and hence establish a positive feedback. The results indicate that generally in colder climates, the presence of sea ice may lead to a significant destabilization of the thermohaline circulation. Brine rejection by sea ice plays no important role in this model’s dynamics. The net destabilizing effect of sea ice in this model is the result of two positive feedbacks and one negative feedback and is shown to be model dependent. To date, the destabilizing feedback between atmospheric and oceanic heat fluxes, mediated by sea ice, has largely been neglected in conceptual studies of thermohaline circulation stability, but it warrants further investigation in more realistic models.

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