Project

General

Profile

Crocus Development in progress »

MEB-Crocus coupling for snow-vegetation interactions

This configuration was developed in order to better describe snow-vegetation interactions in temperate midlatitude climates.

It was initially produced in order to improve snow amount simulations (height and SWE) at the Col de Porte experimental site.
You can try this parameterization for any other site, even in cold climates like boreal forests (but we need more validations to be sure it makes no major degradation in this kind of vegetation).

4 activation keys (flags) can enable this configuration :

→ LMEB_TALL_VEG (bool) : enable this key to use vegetation height as a major variable to calculate maximum snow load on trees and turbulent fluxes. It will mainly increase evaporation and sublimation mass loss on tree branches.

→ LMEB_INT_PHASE_LUN (bool) : enable this key if you want to use the [Lundquist et al., 2021] intercepted snow melt formulation. When you set this key at True, the snow intercepted by the trees (= the snow which is ON the tree branches) melts faster (4kg.m^-2.K^-1.jour^-1) than using the classical config.

→ LMEB_INT_UNLOAD_LUN (bool) : enable this key if you want to use the snow unloading scheme of [Lundquist et al., 2021] (calibration of the [Roesh et al., 2001] scheme). This scheme is globally slowing the solid unloading, which favors snowmelt and sublimation of the intercepted snow as it stays a bit longer on the branches.

→ LMEB_INT_UNLOAD_SFC (bool) : enable this key in order to separate snow unloading from snowfalls in Crocus fresh snow incorporation. When the key is set at True, snow unloading will be included into the Crocus snowpack as “old” snow, with properties of melt forms and a density of 200kg.m^-2 .

You have to place these keys into the NAM_MEB_ISBA namelist.

Simple way : enable all keys to discover the full “temperate interactions” configuration.

This is the way you enable the full parameterization. All the flags need simply to be at true :

&NAM_ISBA
    [...]
    LMEB = .T.
&NAM_MEB_ISBA
    [...]
    LMEB_TALL_VEG = .T.
    LMEB_INT_PHASE_LUN = .T.
    LMEB_INT_UNLOAD_LUN = .T.
    LMEB_INT_UNLOAD_SFC = .T.

Configuration by parts. (Experimental).

You can choose to use just one of the different configuration keys (such as : increase the snow melt of the intercepted snow without using the others modifications.
THIS HAS NOT BEEN TESTED EXHAUSTIVELY YET, MAYBE WEIRD RESULTS.

Any question :