Changes between Version 20 and Version 21 of Documentation/CouplingLMDZ

Timestamp:

2014-10-28T19:25:05+01:00 (10 years ago)

Author:

aducharne

Comment:

--

Documentation/CouplingLMDZ

@@ -16 +16 @@
  [http:"//forge.ipsl.jussieu.fr/orchidee/attachment/wiki/Documentation/CouplingLMDZ/cor2_penman.pdf" "Penman equation"]
  8. Brusaert (2005). Hydrology, p124-135: [http:"//forge.ipsl.jussieu.fr/orchidee/attachment/wiki/Documentation/CouplingLMDZ/brutsaert2005_p124-135.pdf" "Brutsaert 2005"]
-
 [[BR]]
 = EVAPO-TRANSPIRATION =
@@ -58 +57 @@
 Currently the code considers qsat(Ts) and not qsat(T*), and thus overestimates potential evaporation, since Ts is warmer on average than T*.
 
-In the present version, this is tackled by correcting the bare soil evaporation afterwards following Milly's approach.
+In the present version, this is only addressed when computing the bare soil evaporation, which is directly controlled by the potential evaporation, owing to a supply/demand approach. To do so, the demand is not the potential evaporation of ORCHIDEE based on qsat(Ts), but it is reduced by a corrective term following Milly, 1992 (Document 6). This does not create any water/energy conservation pb, since it is used at timestep n to estimate vbeta4 for the calculation of total evaporation at timestep n+1. 
 
 Jan proposed improved approaches based on the Penman-Monteith method to calculate the ETP (formulation that provide smaller ETP than the bulk formulation that is used). They have been developed by Anais Barella during her PhD thesis and tested in forced mode. The correct surface energy budget equation for the implicit coupling is not yet available and work has to be done before implementing this approach in Orchidee.trunk.  http://www.lmd.polytechnique.fr/~intro/Files/2014_These_Barella.pdf).