Changes between Version 4 and Version 5 of DevelopmentActivities/CMIP6/DevelopmentsCMIP6/soil_physic

Timestamp:

2015-02-06T13:34:00+01:00 (9 years ago)

Author:

aducharne

Comment:

--

DevelopmentActivities/CMIP6/DevelopmentsCMIP6/soil_physic

@@ -161 +161 @@
 Depth of thermodynamics [8.0m] >[[BR]]
 in [] are the default values you can if you do not enter anything to the script and which produce a result very similar to what we have today.
-Attached is also the plot produced by the script.
+Attached is also the plot produced by the script [http://forge.ipsl.jussieu.fr/orchidee/attachment/wiki/Meetings/CMIP6/Physic/VerticalLayers.pdf].
 
 There is still the open question if we need a vertical filter for the top layer of thermosoil, and if so we need to specify the filtering depth.
@@ -170 +170 @@
 
 So once we agree on the choice it can be implemented in the trunk. 
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+'''Agnès Ducharne, Fuxing Wang, Fréderique Chéruy, 06/02/15 (meeting)'''
+
+We had a skype meeting today about the soil discretization for water and T. We looked at three discretizations (D1: as in Trunk; D2: 8m for water and T, with the same 17 nodes, and the same location of the top 11 nodes as in D1 for water; D3: 2m for water as in D1 + assumption of uniform profile below, 8m for T as in D2, so that the two diffusion schemes use the same nodes in the top 2m)
+* Spin-up: Fuxing tested this in off-line mode, by repeating the same year, globally (forcing dataset to be specified). Almost all land points reach equilibrium in 20 years for D1, and you need more than 40 years with D2. Fuxing still needs to check how long it takes to reach thermal equilibrium in D3, then to do the same tests online.
+* The goal of the spin-up phase is to compare the different simulations in a comparable state: the next steps will be to compare the water budget + seasonal cycles of T, top SM, surface fluxes and river discharge, between D1 and D2, and the thermal state between D1, D2 and D3. To be tested off-line then on-line. This should allow us to decide which kind of vertical discretization is preferable for CMIP6.v1. No conflict with the above suggestion by Jan, which makes the vertical discretization more flexible.
+* Then, we'll have to check how the chosen discretization performs with the developments of Fuxing regarding the soil termal properties (dependence on soil texture) and heat convection (from which we don't expect a large effect). 
+* We shall not forget the issue of the large T variations in the top soil layer in D2 and D3, with a thin top soil layer for heat diffusion.
+* If the group agrees on using the Reynolds map of texture for CMIP6, with 12 texture classes, this will impose to have a soil depth of at least 9 m for T (then why not 10 m?) + basic checks on the water budgets and T behavior given the new textures.
+* Shall we include permafrost for CMIP6.v1 ? with which soil depth and discretization for T ?
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 === Agreed actions and Agenda ===