Slab ocean model - Revision history

SBhatnagar: /* Notes for users */

2025-09-12T11:27:47Z

‎Notes for users

SBhatnagar: /* Notes for users */

2025-09-12T11:26:37Z

‎Notes for users

SBhatnagar: /* General description */

2025-09-12T11:25:58Z

‎General description

SBhatnagar: /* General description */

2025-09-12T11:25:11Z

‎General description

SBhatnagar: /* General description */

2025-09-12T11:24:35Z

‎General description

SBhatnagar: /* General description */

2025-09-12T09:47:33Z

‎General description

SBhatnagar: /* Notes for users */

2025-04-07T08:55:37Z

‎Notes for users

SBhatnagar: /* Notes for a user */

2025-04-07T08:53:12Z

‎Notes for a user

SBhatnagar: /* General description */

2025-03-19T18:13:40Z

‎General description

SBhatnagar: /* Notes for a user */

2025-03-05T10:04:43Z

‎Notes for a user

@@ Line 96: / Line 96: @@
 The model follows energy conservation. However, if an upper limit on sea ice thickness is prescribed (for e.g., 10 m, for faster convergence), energy conservation can be violated. If one wants to purely conserve energy (at the cost of computation time), no limit on sea ice thickness can be prescribed. It is OK to prescribe an upper limit for the case of modern Earth (however, if your prescription is too small, it can lead to anomalous behaviour like stronger seasonal cycles). However, it might not be accurate to do this for more "exotic" cases like Snowball Earth and tidally locked ocean worlds.
-Convergence - As far as the ocean is concerned, convergence timescales are governed by the thermal inertia and depth of the mixed layer. As an order of magnitude, convergence for Modern Earth with the dynamical slab ocean takes around 50 years.
+Convergence - As far as the ocean is concerned, convergence timescales are governed by the thermal inertia and depth of the mixed layer. As an order of magnitude, convergence for modern Earth with the dynamical slab ocean takes around 50 years from a 290 K isothermal start.
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 [[Category:Generic-Model]]
 == References ==

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 == General description ==
-''Note: This documentation reflects updates introduced in '''revision r3423''' of the ocean module. Users who wish to include the dynamical slab ocean model in their simulations must use '''r3423 or later'''.
+''Note: This documentation reflects updates introduced in '''revision r3423''' of the Generic-PCM. Users who wish to include the dynamical slab ocean model in their simulations must use '''r3423 or later'''.''
 ''
 The slab ocean model is based on the works of [https://ui.adsabs.harvard.edu/abs/2012ClDy...38..379C/abstract Codron (2012)] and Bhatnagar et al. (in review). The model uses the same horizontal grid as the GCM and is composed of two layers. The first layer (50 m depth) represents the surface mixed layer, where the exchanges with the atmosphere take place. The second layer (150 m depth) represents the deep ocean. Each oceanic grid point of the model is defined by the sea ice fraction & thickness and snow thickness.

@@ Line 1: / Line 1: @@
 == General description ==
-Note: This documentation reflects updates introduced in revision r3423 of the ocean module. Users who wish to include the dynamical slab ocean model in their simulations must use r3423 or later.
+''Note: This documentation reflects updates introduced in '''revision r3423''' of the ocean module. Users who wish to include the dynamical slab ocean model in their simulations must use '''r3423 or later'''.
+''
 The slab ocean model is based on the works of [https://ui.adsabs.harvard.edu/abs/2012ClDy...38..379C/abstract Codron (2012)] and Bhatnagar et al. (in review). The model uses the same horizontal grid as the GCM and is composed of two layers. The first layer (50 m depth) represents the surface mixed layer, where the exchanges with the atmosphere take place. The second layer (150 m depth) represents the deep ocean. Each oceanic grid point of the model is defined by the sea ice fraction & thickness and snow thickness.

← Older revision		Revision as of 11:24, 12 September 2025
Line 1:		Line 1:
	== General description ==		== General description ==
		+
		+	Note: This documentation reflects updates introduced in revision r3423 of the ocean module. Users who wish to include the dynamical slab ocean model in their simulations must use r3423 or later.

	The slab ocean model is based on the works of [https://ui.adsabs.harvard.edu/abs/2012ClDy...38..379C/abstract Codron (2012)] and Bhatnagar et al. (in review). The model uses the same horizontal grid as the GCM and is composed of two layers. The first layer (50 m depth) represents the surface mixed layer, where the exchanges with the atmosphere take place. The second layer (150 m depth) represents the deep ocean. Each oceanic grid point of the model is defined by the sea ice fraction & thickness and snow thickness.		The slab ocean model is based on the works of [https://ui.adsabs.harvard.edu/abs/2012ClDy...38..379C/abstract Codron (2012)] and Bhatnagar et al. (in review). The model uses the same horizontal grid as the GCM and is composed of two layers. The first layer (50 m depth) represents the surface mixed layer, where the exchanges with the atmosphere take place. The second layer (150 m depth) represents the deep ocean. Each oceanic grid point of the model is defined by the sea ice fraction & thickness and snow thickness.

← Older revision		Revision as of 08:55, 7 April 2025
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	'''rnat''' is a standard diagfi output, which either represents 0 for oceanic grid points or 1 for continent grid points.		'''rnat''' is a standard diagfi output, which either represents 0 for oceanic grid points or 1 for continent grid points.
		+
		+	For historical reasons, we keep '''albedosnow''' (can be defined in callphys.def, default value=0.5), which is the maximum value that the albedo of sea ice can have.

	The model doesn't permit surface fluxes to enter the deep ocean. The latter is present in the model for exchanges and transport to take place.		The model doesn't permit surface fluxes to enter the deep ocean. The latter is present in the model for exchanges and transport to take place.

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 # '''dt_gm1''', '''dt_gm2''': heating of the surface and deep ocean layers by Gent-McWilliams eddy transport (W/m$$^2$$)
-== Notes for a user ==
+== Notes for users ==
 The slab ocean model is activated in callphys.def with:
   ok_slab_ocean = .true.

@@ Line 1: / Line 1: @@
 == General description ==
-The slab ocean model is primarily based on the work of [https://ui.adsabs.harvard.edu/abs/2012ClDy...38..379C/abstract Codron (2012)]. This model uses the same horizontal grid as the GCM and is composed of two layers. The first layer (50 m depth) represents the surface mixed layer, where the exchanges with the atmosphere take place. The second layer (150 m depth) represents the deep ocean. Each oceanic grid point of the model is defined by the sea ice fraction & thickness and snow thickness.
+The slab ocean model is based on the works of [https://ui.adsabs.harvard.edu/abs/2012ClDy...38..379C/abstract Codron (2012)] and Bhatnagar et al. (in prep). The model uses the same horizontal grid as the GCM and is composed of two layers. The first layer (50 m depth) represents the surface mixed layer, where the exchanges with the atmosphere take place. The second layer (150 m depth) represents the deep ocean. Each oceanic grid point of the model is defined by the sea ice fraction & thickness and snow thickness.
 In general for a slab ocean, the temperature at the ocean surface evolves as per the following equation:

@@ Line 78: / Line 78: @@
 In the old implementation, '''tsea_ice''' was always the temperature of the ice surface. It didn’t matter if snow was on top of it or not because previously, snow had zero heat capacity. But now, since snow has a finite heat capacity, there can be conductive fluxes between the top layer of the sea ice and snow on top of it (if the latter exists). This necessitates two different temperature variables: (1), for the sea ice temperature if snow exists on top of it ('''tice''', which is a global variable within '''ocean_slab_mod'''), and is arguably not useful in physiq_mod and therefore not defined in it), and (2), the temperature of the surface in contact with the atmosphere, which can either be sea ice or snow ('''tsea_ice''', in '''physiq_mod''', as it is essentially a proxy for surface temperature, which is useful for the physics to compute interactions between the ocean and atmosphere). To summarise, '''tice''' and '''tsea_ice''' are only identical if snow does not exist on top of the ice.
-The timestep for updating the slab temperature and ice fraction is given by '''cpl_pas''' (in physics timesteps; default value = once every Earth day). It is recommended to force '''cpl_pas'''= 1 in callphys.def.
+The timestep for updating the slab temperature and ice fraction is given by '''cpl_pas''' (in physics timesteps; default value = once every Earth day). It is recommended to force '''cpl_pas'''= 1 in callphys.def so that the ocean is called every physics timestep.
 '''rnat''' is a standard diagfi output, which either represents 0 for oceanic grid points or 1 for continent grid points.