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Idealized Moist Physics

The idealized_moist_phys_nml only ever needs to be specified if idealized_moist_model = True in atmosphere_nml. It contains options which specify the various modules associated with Isca’s moist physics configurations and is described on Isca's website. Isca also gives numerous example scripts using the idealized_moist_phys_nml namelist.
Some of the most common options are described below:

Options

convection_scheme

string
There are 4 choices of convection schemes, as well as no convection, in Isca:

Default: UNSET

do_simple

bool
If True, use a simplification when calculating relative humidity.
Default: False

do_damping

bool
If True, the damping_driver_nml namelist needs to be specified.
Default: False

Radiation

two_stream_gray

bool
This is one of three choices for radiation, the others being do_rrtm_radiation and do_socrates_radiation. If True, the two_stream_gray_nml namelist needs to be specified.
Default: True

do_rrtm_radiation

bool
This is one of three choices for radiation, the others being two_stream_gray and do_socrates_radiation. If True, the rrtm_radiation_nml namelist needs to be specified.
Default: False

do_socrates_radiation

bool
This is one of three choices for radiation, the others being two_stream_gray and do_rrtm_radiation. If True, the socrates_rad_nml namelist needs to be specified.
Default: False

Turbulence

These options are all related to how Isca computes surface exchange of heat, momentum and humidity.

turb

bool
If True, vertical diffusion is enabled and the vert_turb_driver_nml namelist needs to be specified.
Default: False

do_virtual

bool
If True, the virtual temperature is used in the vertical diffusion module.
Default: False

roughness_moist

float
Roughness length for use in surface moisture exchange.
Default: 0.05

roughness_mom

float
Roughness length for use in surface momentum exchange.
Default: 0.05

roughness_heat

float
Roughness length for use in surface heat exchange.
Default: 0.05

Land and Hydrology

Land and hydrology processes are predominantly dealt with in the surface_flux_nml and the mixed_layer_nml namelists, but land and bucket hydrology options are initialised with the following namelist parameters.

Land is implemented in Isca via adjustment of the roughness length (larger over land), evaporative flux (smaller over land), albedo (larger over land) and mixed layer depth/ heat capacity (smaller over land).

Isca give an example script using land.

The file indicated by land_file_name is generated using the write_land function within isca_tools.

mixed_layer_bc

bool
If True, the mixed_layer module is called and the mixed_layer_nml namelist needs to be specified.
Default: False

land_option

string
There are 3 choices of the land mask in Isca:

  • input - Read land mask from input file.
  • zsurf - Define land where surface geopotential height at model initialisation exceeds a threshold of 10.
  • none - Do not apply land mask.

This should be set to the same value as land_option in the mixed_layer_nml namelist.

Default: none

land_file_name

string
Filename for the input land-mask.
Only ever required if land_option = 'input'.
If the file is called land.nc and is in the input_dir then land_file_name should be INPUT/land.nc.
Default: 'INPUT/land.nc'

land_field_name

string
Field name in the input land-mask netcdf.
Only ever required if land_option = 'input'.
Default: land_mask

land_roughness_prefactor

float
Multiplier on the roughness lengths to allow land-ocean contrast.
Expect this to be greater than 1 because land is rougher than ocean.
Only ever required if land_option is not none.
Default: 1.0

bucket

bool
If True, use bucket hydrology.
Isca give an example script using bucket hydrology.
Default: False

init_bucket_depth

float
Value at which to initialise bucket water depth over ocean (in \(m\)). Should be large.
Only ever required if bucket = .true..
Default: 1000

init_bucket_depth_land

float
Value at which to initialise bucket water depth over land (in \(m\)).
Only ever required if bucket = .true..
Default: 20

max_bucket_depth_land

float
Maximum depth of water in bucket over land following initialisation..
Only ever required if bucket = .true..
Default: 0.15

robert_bucket

float
Robert coefficient for Roberts-Asselin-Williams filter on bucket leapfrog timestepping.
Only ever required if bucket = .true..
Default: 0.04

raw_bucket

float
RAW coefficient for Roberts-Asselin-Williams filter on bucket leapfrog timestepping.
Only ever required if bucket = .true..
Default: 0.53

Diagnostics

The diagnostics for this module can be specified using the module_name of atmosphere in the diagnostic table file. The list of available diagnostics is available on Isca's website. Some are also given below:

rh

Relative humidity.
Dimensions: time, lat, lon, pressure
Units: \(\%\)

precipitation

Rain and Snow from resolved and parameterised condensation/convection.
Dimensions: time, lat, lon
Units: \(kgm^{-2}s^{-1}\)

Condensation

condensation_rain

Rain from condensation.
Dimensions: time, lat, lon
Units: \(kgm^{-2}s^{-1}\)

dt_qg_condensation

Moisture tendency from condensation.
Dimensions: time, lat, lon, pressure
Units: \(kgkg^{-1}s^{-1}\)

dt_tg_condensation

Temperature tendency from condensation.
Dimensions: time, lat, lon, pressure
Units: \(Ks^{-1}\)

Convection

convection_rain

Convective precipitation.
Dimensions: time, lat, lon
Units: \(kgm^{-2}s^{-1}\)

dt_qg_convection

Moisture tendency from convection.
Dimensions: time, lat, lon, pressure
Units: \(kgkg^{-1}s^{-1}\)

dt_tg_convection

Temperature tendency from convection.
Dimensions: time, lat, lon, pressure
Units: \(Ks^{-1}\)

cape

Convective Available Potential Energy.
Dimensions: time, lat, lon
Units: \(Jkg^{-1}\)

cin

Convective Inhibition.
Dimensions: time, lat, lon
Units: \(Jkg^{-1}\)

Near Surface Variables

temp_2m

Air temperature \(2m\) above surface.
Dimensions: time, lat, lon
Units: \(K\)

sphum_2m

Specific humidity \(2m\) above surface.
Dimensions: time, lat, lon
Units: \(kg/kg\)

rh_2m

Relative humidity \(2m\) above surface.
Dimensions: time, lat, lon
Units: \(\%\)

u_10m

Zonal wind \(10m\) above surface.
Dimensions: time, lat, lon
Units: \(ms^{-1}\)

v_10m

Meridional wind \(10m\) above surface.
Dimensions: time, lat, lon
Units: \(ms^{-1}\)