Double-Diffusive Convection and Interleaving in the Arctic Ocean – Distribution and Importance

• Main Authors: Bert Rudels, Natalia Kuzmina, Ursula Schauer, Tapani Stipa, Victor Zhurbas
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2009
• Subjects: Arctic; Arctic Ocean
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.602.5235; http://www.geophysica.fi/pdf/geophysica_2009_45_1-2_199_rudels.pdf

Beneath its ice cover the Arctic Ocean is a low energy environment. The weak turbulent activity allows other, more esoteric mixing mechanisms to become important in transforming the water masses. One such process is double-diffusive convection, which is triggered by the different molecular diffusion rates of heat and salt and utilises the potential energy stored in the unstably stratified component, heat or salt, to increase the vertical transports. Cold, fresh water above warm, saline water leads to the formation of diffusive interfaces, while warm and saline water above cooler and fresher water results in saltfingers. The former situation is more representative of the Arctic Ocean and the vertical heat transport through diffusive interfaces could contribute significantly to the upward flux of heat from the subsurface warm Atlantic water to the upper layers. The lateral property contrasts between the different inflow branches to the Arctic Ocean and between the boundary current and the water columns of the different basins allow finite lateral disturbances to create intrusions and inversions in the temperature and salinity profiles. These in turn cause double-diffusive transports, which generate convergences and divergences in the vertical buoyancy fluxes, reinforcing the lateral interleaving between the different water masses. Although the interleaving structures are most prominent at frontal zones, they appear to