Model-Data Intercomparison for Marginal Sea Overflows

LONG-TERM GOALS The primary goal of this project is to enhance our understanding of the dynamics of oceanic overflows, which are characterized by high levels of turbulence and mixing near strategic straits connecting various marginal seas and oceans. OBJECTIVES 1) To complement field studies and to develop a better understanding of the characteristics of mixing and its influence on the subsequence fate of the overflows. 2) To address the fundamental issue of entrainment of a plume in the presence of rotation and ambient stratification. 3) To develop parameterizations of mixing for ocean general circulation models. 4) To explore the large-scale impact of mixing in overflows. APPROACH The research is being carried out primarily by comparing results from a high-resolution twodimensional nonhydrostatic numerical model to field measurements. Ocean general circulation models and analytical techniques are also being used. WORK COMPLETED The primary accomplishments during this grant period are as follows: 1) Successful validation and benchmarking of a two-dimensional, nonhydrostatic numerical model using laboratory experiments bottom gravity currents. This study led to a manuscript that is accepted for publication in the Journal of Physical Oceanography (Ozgokmen and Chassignet, 2001). 2) Publication of a paper in the Journal of Physical Oceanography describing the large-scale impact of the Mediterranean overflow on the upper-level circulation in the North Atlantic Ocean (Ozgokmen et al., 2001).