(ocean-single-column)= # single column ## description The `single_column` tasks include any ocean tests of the vertical ocean dynamics. ## suppported models These tasks support only MPAS-Ocean. ## mesh The mesh is planar and spans the minimum number of cells (16 for MPAS-Ocean). The config options `lx` and `ly` are given arbitrarily small values of 1 m in order to ensure that the minimum number of cells is chosen. By virtue of testing the vertical dynamics, these tests should be insensitive to the horizontal resolution. As such, only 10 km horizontal resolution is currently supported. ## vertical grid Currently, these tests feature a very fine vertical resolution of 4 m with 100 vertical levels. Future work may want to examine vertical mixing or advection at typical vertical resolutions. ## config options ```cfg # Options related to the vertical grid [vertical_grid] # the type of vertical grid grid_type = uniform # Number of vertical levels vert_levels = 100 # Depth of the bottom of the ocean bottom_depth = 400.0 # The type of vertical coordinate (e.g. z-level, z-star) coord_type = z-star # Whether to use "partial" or "full", or "None" to not alter the topography partial_cell_type = None # The minimum fraction of a layer for partial cells min_pc_fraction = 0.1 ``` ## initial conditions The temperature and salinity profiles are defined using the following equations: $$ \Phi(z) = \begin{cases} \Phi_0 &\text{ if } z = z[0]\\ \Phi_0 + {d\Phi/dz}_{ML} z & \text{ if } z > z_{MLD}\\ (\Phi_0 + {\Delta\Phi}_{ML}) + {d\Phi/dz}_{int} (z - z_{MLD}) & \text{ if } z \le z_{MLD} \end{cases} $$ where $\Phi_0 = $`surface_X`, ${d\Phi/dz}_{ML} = $`X_gradient_mixed_layer`, $z_{MLD} = -$`mixed_layer_depth_X`, ${\Delta\Phi}_{ML} = $ `X_difference_across_mixed_layer`, and ${d\Phi/dz}_{int} = $ `X_gradient_interior`. `X` in the config options above is either `temperature` or `salinity`. The water column is initially stationary (`normalVelocity`$=0$). The Coriolis parameter is spatially constant and set equal to `coriolis_parameter`. ## config options ```cfg # config options for single column testcases [single_column] # size of the domain (typically the minimum allowed size of 4x4 cells) nx = 4 ny = 4 # resolution in km resolution = 960.0 # Surface temperature surface_temperature = 20.0 # Temperature gradient in the mixed layer in degC/m temperature_gradient_mixed_layer = 0.0 # The temperature below the mixed layer temperature_difference_across_mixed_layer = 0.0 # Temperature gradient below the mixed layer temperature_gradient_interior = 0.01 # Depth of the temperature mixed layer mixed_layer_depth_temperature = 25.0 # Surface salinity surface_salinity = 35.0 # Salinity gradient in the mixed layer in PSU/m salinity_gradient_mixed_layer = 0.0 # The salinity below the mixed layer salinity_difference_across_mixed_layer = 1.0 # Salinity gradient below the mixed layer salinity_gradient_interior = 0.0 # Depth of the salinity mixed layer mixed_layer_depth_salinity = 0.0 # coriolis parameter coriolis_parameter = 1.0e-4 ``` See mesh section for a description of `lx` and `ly` and initial conditions section for a description of the remaining config options. (ocean-single-column-cvmix)= ## cvmix ### description The `cvmix` test exercises the [CVMix](https://github.com/CVMix/CVMix-src) schemes for vertical mixing. The temperature and salinity profiles only evolve a small amount over the 1- day duration of the test, so the 10-day profiles are shown here: ```{image} images/single_column_temperature_10day.png :align: center :width: 200 px ``` ```{image} images/single_column_salinity_10day.png :align: center :width: 200 px ``` The namelist options for this test case dictate that the KPP scheme is tested. ### mesh See {ref}`ocean-single-column`. ## vertical grid See {ref}`ocean-single-column`. ### initial conditions See {ref}`ocean-single-column`. ### forcing The cvmix case has both surface forcing and restoring, which are controlled by the following config options: ```cfg # config options for forcing single column testcases [single_column_forcing] # Piston velocity to control rate of restoring toward temperature_surface_restoring_value temperature_piston_velocity = 4.0e-6 # Piston velocity to control rate of restoring toward salinity_surface_restoring_value salinity_piston_velocity = 4.0e-6 # Temperature to restore towards when surface restoring is turned on temperature_surface_restoring_value = 15.0 # Salinity to restore towards when surface restoring is turned on salinity_surface_restoring_value = 36.0 # Rate at which temperature is restored toward the initial condition temperature_interior_restoring_rate = 1.0e-6 # Rate at which salinity is restored toward the initial condition salinity_interior_restoring_rate = 1.0e-6 # Net latent heat flux applied when bulk forcing is used. Positive values indicate a net # input of heat to ocean latent_heat_flux = -50.0 # Net sensible heat flux applied when bulk forcing is used. Positive values indicate a # net input of heat to ocean sensible_heat_flux = -25.0 # Net solar shortwave heat flux applied when bulk forcing is used. Positive values # indicate a net input of heat to ocean shortwave_heat_flux = 200.0 # Net surface evaporation when bulk forcing is used. Positive values indicate a net # input of water to ocean evaporation_flux = 6.5E-4 # Net surface rain flux when bulk forcing is used. Positive values indicate a net input # of water to ocean rain_flux = 0.0 # Zonal surface wind stress over the domain wind_stress_zonal = 0.1 # Meridional surface wind stress over the domain wind_stress_meridional = 0.0 ``` ### time step and run duration The time step is given as 10 min and the barotropic time step is 30s. The run duration is 1 day. ### config options See {ref}`ocean-single-column`. Currently, config options are only given in the shared framework. ### cores Both default and minimum number of cores are hard-coded as 1 given that the domain is only 16 cells. (ocean-single-column-ideal-age)= ## ideal age The `ideal age` test exercises the ideal age tracers. ### description Temperature and salinity profiles evolve in the same way as in the {ref}`ocean-single-column-cvmix` test case. 10-day profiles for the ideal age tracer are as follows: ```{image} images/single_column_ideal_age_tracer_10day.png :align: center :width: 200 px ``` ### mesh See {ref}`ocean-single-column`. ### vertical grid See {ref}`ocean-single-column`. ### initial conditions `idealAgeTracers` is initialized as zero seconds throughout the water column. ### forcing `idealAgeTracers` is set to zero seconds within the first surface grid layer at every time step. ### time step and run duration See {ref}`ocean-single-column-cvmix`. ### config options See {ref}`ocean-single-column`. Currently, config options are only given in the shared framework. ### cores See {ref}`ocean-single-column-cvmix`.