Changes between Version 128 and Version 129 of Documentation/TrunkFunctionality4

Timestamp:

2022-11-04T20:02:17+01:00 (20 months ago)

Author:

mmcgrath

Comment:

--

Documentation/TrunkFunctionality4

@@ -231 +231 @@
 The above declaration implies that 9/15th of the trees will always be in the smallest diameter class, 5/15th will be in the medium class and 1 tree out of 15 will be in the largest diameter class. These ratios are kept throughout the simulations and the boundaries of the diameter classes are adjusted to respect this constraint. Consequently, an even-aged stand will be simulated with three diameter classes where the diameter of the first class may be, for example, 20.3 cm, the diameter of the second class 20.4 cm and the diameter of the third class 20.5 cm. The same code and set-up allows to simulate, in the same simulation, an uneven-aged stand for the same PFT but in a different pixel with, for example, the smallest diameter 7 cm, the medium diameter 25 cm and the largest diameter 45 cm.
 
-
 === Forced clear cut ===
 Describes r6614. '''FORCED_CLEAR_CUT''' is a flag used to force ORCHIDEE trunk to clearcut a forest after one year of simulation. This flag is set to TRUE in order to start a new stand at the beginning of the FIN step in ENSEMBLE runs. It helps us to control the stand age at the end of the HIST step. If you want to use this flag for other purposes, do not forget that a clearcut means that the majority of the living biomass is removed (circ_class_biomass for sapwood and heartwood), but the other pools are transferred in the litter pool (leaf, branches, fruit, fine root). Note that if '''FORCED_CLEAR_CUT''' is used, the model will clearcut at the end of every year in that run. The typical set-up should be: 300 years of spin-up with '''FORCED_CLEAR_CUT''' set to FALSE, 1 year with '''FORCED_CLEAR_CUT''' set to TRUE, a simulation with the length similar to the age of the forest with '''FORCED_CLEAR_CUT''' set to FALSE. 
@@ -468 +467 @@
 
 The soil hydrology model distinguishes three water columns, the so called soil tiles. The first soil tile simulates the water contained under PFT1, the second the soil water contained under forest PFTs and the third the water contained under short vegetation PFTs (grasses and crops). PFTs are linked to soil tiles by means of the parameter '''pref_soil_veg''' (in src_parameters/constantes_mtc.f90). Note that both transpiration (veget) and evaporation (frac_bare_ns) is taken from the same soil tile.
+
+=== Potential evaporation ===
+Describes TAG4.1 (r7761).  
+
+Uses the method proposed by Milly (1992) to predict the potential evaporation at a specified temperature from a surface well-supplied with water based on the potential evaporation at a temperature which has been calculated using the actual surface evaporation.  This latter method is what results from solving the energy budget, but the former allows for calculating the evaporation with a simple empirical function for the moisture availability that is well-constrained by observations.  By using this correction, the model can use this moisture availiability function without recalculating the energy budget.  The function in enerbil_flux has been updated with a few small bug fixes, but the correction does not appear to have been touched since ORC2 (or before).  
 
 === Prescribe initial vegetation ===