Effects of enhanced resolution in the North Sea and the Skagerrak
Inge K. Eliassen and Jarle Berntsen
Abstract
A three dimensional sigma-coordinate model has been implemented for
an extended North Sea with 20 km horizontal resolution and for
a subarea including the central North Sea, the Skagerrak and the
Norwegian Trench with 4 km horizontal resolution.
The models are forced with hindcast atmospheric forcing, 4 components
of the tide and river runoff and run for the period from 15/1-1990 to
24/6-1990.
Model results are compared to measurements taken across a transect
from the Norwegian coast to the Orkneys and to measurements from
repeated hydrographical transects across Skagerrak taken in 1990, the
SKAGEX dataset.
It is shown that the enhanced resolution allows important smaller
scale phenomenas to appear in the numerical solutions and the effects
of these smaller scale features on the larger scale fields are
demonstrated.
These effects include finer structures and additional patchiness in
tracer plots, and a 10-20 km wide south going coastal jet
along the Norwegian coast.
Furthermore, the convergence zone along the Norwegian Trench shelf
break becomes more realistic.
The effects of the improved resolution are quantified using the SKAGEX
dataset.
Keywords: Ocean Models, resolution, validation, the
North Sea, the Skagerrak