Constructing an idealized model of the North Atlantic Ocean using slippery sacks     

Patrick T. Haertel  Luke Van Roekel  Tommy G. Jensen   《Ocean Modelling》2009,27(3-4):143-159

This paper documents the continued development and testing of a new Lagrangian oceanic general circulation model. The slippery sacks ocean model (SSOM), which represents a body of water as a pile of conforming parcels, is improved and is used to simulate circulations in homogeneous oceans and in an idealized model of the North Atlantic Ocean.A method for including horizontal mixing in the SSOM is presented. A given sack’s nearest neighbors are identified in the positive and negative x- and y-directions, and the sack exchanges momentum and/or tracers with these neighbors. This formulation of mixing is straightforward to implement, computationally efficient, and it produces results similar to a standard Eulerian finite-difference representation of diffusion.The model’s ability to reproduce the Stommel and Munk solutions to the classical western boundary current problem is tested. When steps are taken to reduce the potential energy barrier to sacks crossing one another, the model generates circulations that are consistent with linear theory. In moderately non-linear regimes the model produces appropriate departures from linear solutions including a boundary current that continues along the northern boundary for a time.Taking advantage of the new mixing scheme and lessons learned from simulations of homogeneous oceans, the authors construct an idealized model of the North Atlantic Ocean. They compare simulations conducted with the SSOM to similar simulations conducted with the Massachusetts Institute of Technology general circulation model (MITgcm). The SSOM and the MITgcm produce similar wind-forced gyres, thermocline structure, and meridional overturning. The SSOM is also used to explore how circulations change in the limit when tracer diffusion goes to zero.  相似文献