Changes between Version 5 and Version 6 of DevelopmentActivities/CMIP6/DevelopmentsCMIP6/snow

03/29/16 17:52:27 (5 years ago)



  • DevelopmentActivities/CMIP6/DevelopmentsCMIP6/snow

    v5 v6  
    66A first commit was done in revision [3269] to fix the snowmelt problem.[[BR]] 
    8 Some explanations (soon in English):[[BR]] 
     8Some explanations (English version below):[[BR]] 
    99'''Révision du modèle de neige dans Orchidee'''[[BR]] 
    1010Les modifications effectuées par Tao et Fuxing pour rendre le schéma de neige implicite, ont consisté en :  
    1818Ainsi la résolution des températures dans la neige et le sol restent bien implicites tout en prenant en compte les températures temps_sol_add (pour la neige) et temps_sol_new (pour la neige et le sol).  
     22The changes made by Tao and Fuxing to make the snow code totally implicit, consisted in:  
     23- Displacement of the routines for calculating the temperature of the three layers of snow (snow-explicit-profile) and the thermal coefficients (explicit-snow-coef) in thermosoil.f90 
     24- temp_sol_add (excess temperature available for the melting of snow at the interface with the atmosphere, calculated from the surface energy balance) was not considered in the calculation of snow-temp 
     25- Set of temp_sol_new to the melting temperature (0 °C) (surface temperature solution of the energy balance calculated by enerbil_fusion) in presence of snow after the calculation of the snow melting and before the calculation of the temperature profile in the snow and in the soil. 
     27These changes explain why the snow pack could never melt because temp_sol_add was not considered in the calculation of snowmelt. Moreover, temp_sol_new was always kept to 0 after the melting of snow (calculated in explicit_snow) and before the calculation of the soil and snow temperatures in thermosoil.f90 (in presence of snow). Thus, the snow and soil temperatures were calculated without taking into account the energy available at the snow-atmosphere interface. 
     29To correct the scheme, it is therefore proposed: 
     30- To reset the calculation of the snow temperature profile in explicit-snow.f90, taking into account temp_sol_add to properly calculate the snowmelt but to leave (to keep plutôt que to leave) the calculation of the temperature coefficients (for the next time step) in thermosoil.f90, in order to calculate snow and soil temperatures at time step t. 
     31- To transfer the lines of code initially in enerbil_fusion.f90 which return the snow surface temperature (temp_sol_new) to the melting temperature (0 °C), after the calculation of snow and soil temperatures, that is to say, at the end of thermosoil.f90. 
     33Thus the resolution of both snow and soil temperatures are well implicitly calculated  taking into account the temp_sol_add temperature (for snow) and temp_sol_new (for snow and soil).