Opened 6 years ago

Closed 6 years ago

#179 closed enhancement (fixed)

Update of the explict snow scheme

Reported by: jgipsl Owned by: jgipsl
Priority: major Milestone: IPSLCM6.v1
Component: Physical processes Version:
Keywords: Cc:

Description

To be more consistent with the structure of ORCHIDEE, the previous snow module has been adapted but the main snow processes (e.g. snow freezing/thawing, the spatio-temporal variation in snow density and snow thermal conductivity, snow insulation effect on soil temperature) are kept in the revised snow module.

A significant change is to resolve the snow temperature profile following the same strategy of soil temperature calculation in thermosoil.f90. That is to say, the heat diffusion equation is solved numerically to calculate the soil and snow temperatures for a 7-layer soil column with up to 3 overlying layers of snow with the boundary conditions of the heat flux into the top soil and snow from the overlying atmosphere and zero heat flux at the bottom of the soil column. The temperature profile for snow is calculated first without phase change and then readjusted for phase change.

In addition, there are other changes:

  1. the snow albedo scheme in previous snow module has been abandoned since the simulated snow albedo have been demonstrated to be much more relied on the initial snow albedo value than the albedo scheme itself; the old snow albedo scheme was restored in the revised snow module;
  1. in previous multi-layer snow module, the first snow layer was adopted to resolve the surface energy balance if there was snow on the ground. Now this is abandoned and the skin layer to resolve the surface energy balance was restored in the revised snow module;
  1. in the revised snow module, the attenuation of solar radiation by different snow layers has not been considered for simplification;

Although there are significant changes compared to previous multi-layer snow module, the revised snow module performs as good as the previous one in terms of snow water equivalent, snow depth, runoff and soil thermal regimes

Tao Wang

Above changes will soon be commited in the trunk.

Change History (2)

comment:1 Changed 6 years ago by jgipsl

  • Summary changed from Upate of the explict snow scheme to Update of the explict snow scheme

Commit of above modifications done in the trunk rev [2650].

comment:2 Changed 6 years ago by jgipsl

  • Resolution set to fixed
  • Status changed from new to closed
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