Vertical Advection
Overview
In Omega, vertical advection represents the transport of mass, momentum, and tracer quantities along the vertical coordinate due to vertical motion within a water column. In the context of Omega’s governing equations, vertical advection contributes to the tendencies of pseudo-thickness, horizontal velocity, and tracer fields. Vertical motion is inferred from the divergence of horizontal flow through the continuity equation and is necessary for accurately representing vertical transport in three-dimensional ocean simulations.
The VertAdv class contains variables and functions for computing the vertical
velocity and the tendencies of LayerThickness, NormalVelocity, and
Tracers. The algorithms used are determined by options specified in the
configuration file.
Configuration Options
Within the Tendencies group of the configuration file, flags are used to
enable or disable the contribution of vertical advection to the tendencies of
thickness, velocity, and tracers:
Configuration name |
Options |
|---|---|
ThicknessVertAdvTendencyEnable |
true / false |
VelocityVertAdvTendencyEnable |
true / false |
TracerVertAdvTendencyEnable |
true / false |
Within the Advection group, options are provided to configure the algorithms
used to compute the tracer tendencies:
Configuration name |
Description |
Options |
|---|---|---|
VerticalTracerFluxOrder |
order of accuracy used for the tracer flux calculation |
2, 3, or 4 |
VerticalTracerFluxLimiterEnable |
selects the tracer tendency algorithm |
true / false |
Coef3rdOrder |
coefficient used for blending 3rd- and 4th-order fluxes when |
0.0 - 1.0 |
For VerticalTracerFluxLimiterEnable, true enables flux-corrected transport,
and false selects the standard algorithm. For Coef3rdOrder, 1 corresponds
to purely 3rd-order, 0 purely 4th-order.
The VertAdv class provides four fields that can be written to output:
VerticalVelocity, TotalVerticalVelocity, VertFlux, and LowOrderVertFlux.
These fields collectively make up the VertAdv output group.