A model/data comparison was performed between simulated drifters from a high 
resolution numerical simulation of the North Atlantic and a data set from 
in-situ surface drifters. The model is a version of the Miami Isopycnic 
Coordinate Ocean Model, with 1/12 deg horizontal grid spacing, and 16 layers (a 
bulk mixed layer and 15 isopycnic layers), forced with COADS climatological 
fields.

The comparison makes use of pseudo-Eulerian statistics such as mean velocity 
and eddy kinetic energy, and Lagrangian statistics such as integral time scales. 
Comparisons of eddy kinetic energy and root mean square velocity indicate that 
the numerical model underestimates the eddy kinetic energy in the Gulf Stream 
extension and in the ocean interior. In addition, the model Lagrangian time 
scales are longer in the interior than the in-situ time scales by approximately 
a factor of two. It is suggested that this is primarily due to the lack of high 
frequency winds in the model forcing, which causes an underestimation of the 
directly forced eddy variability. The mean flow comparison has been performed 
both qualitatively and quantitatively using James' statistical test. The results 
indicate that over most of the domain, the differences between model and in-situ 
estimates are not significant. However, some areas of significant differences 
exist, close to high energy regions, notably around the Gulf Stream path, which 
in the model lies slightly north of the observed path, although its strength and 
structure are well represented overall. Mean currents close to the buffer zones, 
primarily the Azores Current, also exhibit significant differences between model 
results and in-situ estimates.

Results of a second North Atlantic numerical simulation forced with ECMWF 
climatology are discussed in comparison with the COADS forced simulation.