Deep convection in the Arctic: The evaluation of results from an OGCM with a new convection parameterization

• Main Authors: Paluszkiewicz, T., Hibler, L.F., Romea, R.D.
• Other Authors: United States. Department of Energy.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Pacific Northwest Laboratory 1995
• Subjects: Oceanic Circulation; Seas; General Circulation Models; Stratification; 54 Environmental Sciences; Parametric Analysis; Convection; Arctic Regions; Accuracy; Arctic; Nordic Seas
• Online Access: http://digital.library.unt.edu/ark:/67531/metadc676684/

The current generation of ocean general circulation models (OGCMS) uses a convective adjustment scheme to remove static instabilities and to parameterize shallow and deep convection. In simulations used to examine climate-related scenarios, investigators found that in the Arctic regions, the OGCM simulations did not produce a realistic vertical density structure, did not create the correct quantity of deep water, and did not use a time-scale of adjustment that is in agreement with tracer ages or observations. A possible weakness of the models is that the convective adjustment scheme does not represent the process of deep convection adequately. Consequently, a penetrative plume mixing scheme has been developed to parameterize the process of deep open-ocean convection in OGCMS. This new deep convection parameterization was incorporated into the Semtner and Chervin (1988) OGCM. The modified model (with the new parameterization) was run in a simplified Nordic Seas test basin: under a cyclonic wind stress and cooling, stratification of the basin-scale gyre is eroded and deep mixing occurs in the center of the gyre. In contrast, in the OGCM experiment that uses the standard convective adjustment algorithm, mixing is delayed and is wide-spread over the gyre.