Impact of 1/8 degree to 1/64 degree Resolution on Gulf Stream Model-Data Comparisons in Basin-Scale Subtropical Atlantic Ocean Models
Abstract
We investigate the impact of 1/8 deg, 1/16 deg, 1/32 deg, and 1/64 deg ocean model resolution on model-data comparisons for the Gulf Stream system between the Florida Straits and the Grand Banks. This includes mean flow and variability, the Gulf Stream pathway, the associated nonlinear recirculation gyres, the large-scale C-shape of the subtropical gyre, and the abyssal circulation. A nonlinear isopycnal, free surface model covering the Atlantic from 9 deg N to 47 deg N or 51 deg N, including the Caribbean and Gulf of Mexico, and a similar 1/16 deg global model are used. The models are forced by winds and by a global thermohaline component via ports in the model boundaries. When calculated using realistic wind forcing and Atlantic model boundaries, linear simulations with Munk western boundary layers and a Sverdrup interior show two unrealistic mean Gulf Stream pathways between Cape Hatteras and the Grand Banks, one proceeding due east from Cape Hatteras, and a second one continuing northward along the western boundary until forced eastward by the regional northern boundary. The northern pathway is augmented when a linear version of the upper ocean global thermohaline contribution to the Gulf Stream is added as a Munk western boundary layer. A major change is required to obtain a realistic pathway in nonlinear models. Resolution of 1/8 deg is eddy-resolving, but mainly gives a wiggly version of the linear model Gulf Stream pathway and weak abyssal flows except for the deep western boundary current forced by ports in the model boundaries. All of the higher resolution simulations show major improvement over the linear and 1/8 deg nonlinear simulations. Additional major improvement is seen with the increase from 1/16 deg to 1/32 deg resolution and modest improvement with a further increase to 1/64 deg.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2000
- Accession Number
- ADA531039
Entities
People
- Harley E. Hurlburt
- Patrick J. Hogan
Organizations
- United States Naval Research Laboratory