# SurfaceFlow

## SurfaceFlow types and functions

ClimateMachine.Land.SurfaceFlow.OverlandFlowModelType
OverlandFlowModel{Sx,Sy,M} <: BalanceLaw

The 2D overland flow model, with a prognostic variable equal to the height of the surface water.

This model simulates the depth-averaged shallow water equation under the kinematic approximation, and employs Manning's relationship to relate velocity to the height of the water.

Fields

• slope_x

Slope in x direction; field(x,y), unitless

• slope_y

Slope in y direction; field(x,y), unitless

• mannings

Mannings coefficient; field(x,y), units of s/m^(1/3)

source
ClimateMachine.Land.SurfaceFlow.surface_boundary_flux!Function
surface_boundary_flux!(
nf,
bc::Land.Dirichlet,
model::OverlandFlowModel,
land::LandModel,
_...,
)

The surface boundary flux function for the OverlandFlow model, which does nothing if Dirichlet conditions are chosen in order to not overconstrain the solution.

source
ClimateMachine.Land.SurfaceFlow.surface_boundary_state!Function
surface_boundary_state!(
nf,
bc::Land.Dirichlet,
model::OverlandFlowModel,
land::LandModel,
state⁺::Vars,
aux⁺::Vars,
nM,
state⁻::Vars,
aux⁻::Vars,
t,
_...,
)

The surface boundary state function for the OverlandFlow model when Dirichlet conditions are chosen. This should be equivalent to outflow boundary conditions, also referred to as gradient outlet conditions.

source