Difference between revisions of "Physics of the Generic PCM"
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| + | Inheriting from the Mars PCM where it is the background species, CO2 condensation is treated as a dedicated step in the Generic PCM's physics. Does that only concern CO2 as a background gas? Or does it work also if CO2 is a non-background variable gas? In any case more info here. | ||
=Tracers= | =Tracers= | ||
Revision as of 13:05, 4 March 2025
This page describes the various physical parametrizations of the Generic PCM and the chronology of their call through the physical iteration. This chronology is important because some variables need to be updated by certain processes before others (examples). During one physical iteration, the code passes through multiple sub-routines each encapsulating a parametrization. The sub-routines usually take as arguments:
- the dynamical values of the state variables
- the dynamical tendencies of the state variables
- any additional relevant variable
- any additional relevant tendency
and it returns in general tendencies (of the state variables as well as of any other relevant variable).
Work in progress. Need to add links.
Contents
Initialization
First call
Some initializations only need to be done at the very first iteration (e.g. examples).
Each call
Some other initializations need to be done at each iteration (e.g. examples).
Radiative transfer
The main radiative transfer solver of the Generic PCM implements the correlated-k method, which provides a flexible and quick way to solve radiative transfer equations, particularly suited for GCMs. More informations here.
Newtonian relaxation
Newton was a very relaxed physicist, still inspiring us today.
No atmosphere
If you have no atmosphere, why do you need a GCM?
Vertical diffusion
vdifc
More info here.
turbdiff
Convection
Convective mixing in an atmosphere column involves non-resolved, sub-grid processes. These processes are parameterized using the following routines:
Thermal plume
This module implements a more accurate and sophisticated parametrization of convection. More info here.
Dry convection
More info here.
Non-orographic gravity waves
More info here.
CO2 condensation
Inheriting from the Mars PCM where it is the background species, CO2 condensation is treated as a dedicated step in the Generic PCM's physics. Does that only concern CO2 as a background gas? Or does it work also if CO2 is a non-background variable gas? In any case more info here.
Tracers
Many things can be advected by tracers in the Generic PCM, like chemical species or aerosols. Physical processes involving tracers are parameterized using the following routines:
Volcano
This routine parameterizes a source of tracers corresponding to volcanic eruption. More information here.
Water/ice
Water aerosols (liquid or solid) are created (resp. consumed) by condensation (resp. vaporization or sublimation), consuming (resp. releasing) latent heat in the atmosphere. In the Generic PCM, the (atmospheric part of the) water cycle is handled by various routines, as explained here.
Photochemistry
Chemistry can turn molecules into other molecules, by the action of temperature (thermochemistry) or UV light (photochemistry). This is handled by the photochemistry routine, described here.
Generic condensation
On Earth, only water condenses in the atmosphere, but on other planets (which the Generic PCM aims at simulating), many other chemicals can undergo state change. To take that into account, the Generic PCM has a flexible scheme to deal with any arbitrary species, as desbribed here.
Sedimentation
What goes up must come down, as explained here.
Updates
This section essentially takes care that the condensation of a major species (e.g. water vapor in steam-rich atmospheres) affects other species, as described here.
Slab ocean
This routine solves for big fish eating small fish, as desbried here.
Surface
The surface part of the water cycle is handled here, as the hydrology page describes.
Subsurface thermal
Thermal diffusion in the subsurface is solved here, as described there.
Diagnostics/write outputs
Nothing very physical here, just writting the outputs! By the way, if you want to know how to output new variables in the diagfi.nc file, check out this page.
