Description
1 Model setup
A model of a mid latitude, stratified gyre was set up using the Regional Ocean Modeling Sys- tem(ROMS). The gyre was started from an initial state of rest, and forced by a cosine wind stress of the form, τ = τ0 ∗cos(π/L∗y), where τ is the wind stress (with units N/m2), y is the distance in the north-south direction, and L is the meridional extent of the model domain. The domain size is 2000 × 2000 km with a lateral resolution of 10 km, configured on a Cartesian grid. The model was run for 2.5 years, and advection of momentum was left out in order to investigate the near-linear evolution of the system. ROMS is a generalized vertical sigma-coordinate model that facilitate stretching of the layers to obtain higher vertical resolution where desired. This model run however was simulated without any stretching applied, each layer is thereby 100m deep.
The model setup and model parameters is summarized in the tables below:
Model setup
Runtime 2.5 years betaplane approximation f = f0 + β0y Size of domain 2000 × 2000km Lateral esolution 10 × 10[km] Number of vertical layers 10
Vertical resolution 100m Advection of momentum OFF Slipperiness parameter Free-slip Linear bottom drag ON Harmonic friction ON
Parameter values:
f0 =7.5e-05 β0 = 2e-11 R = 5e-04 Ah = 400 tau0 = 0.03
Ttop = 15
[1/s]
[1/ms]
[m/s]
[m2 /s]
[N/m2 ] [Celsius] [Celsius/layer]
[kg/m3] [Celsius] []
[] [1/Celsius]
dT dN
Linear equation of State parameters:
ρ0 = 1027.0d0 T0 = 10.0d0 S0 = 32.0d0 βS = 7.6d-4 αT = 1.7d-4
= -1.5
1
