DenisPishniak
New member
Hi,
I am studying the melting of snow cover over the coast of West Antarctica. In an attempt to find a heat source of melting during the case study I discovered that it was mainly produced by “Freezing rain latent heat flux” (variable FLX2) as an uncompensated part of surface heat budget.
In my opinion Freezing rain latent heat flux may release only when air temperature or at least ground temperature is below 0 and never can produce additional melting at the current moment, isn’t it? But it looks like the LSM model does not divide the region into already warm, wet snow cover and really frozen surface at higher altitudes. As a result, a huge melting and runoff (SFROFF) was obtained during the rain episode. 2m air temperature (T2) was +2C and Surface skin temperature (TSK) = 0C. It can be noticed on the attached figure around 39 time step.
I wouldn't be surprised if I missed some settings or input for this to work correctly.
The corresponding equation chain from phys/module_sf_noahlsm.F :
FLX3 = FDOWN - FLX1- FLX2- EMISSI*SIGMA * T14- SSOIL - SEH - ETANRG
EX = FLX3*0.001/ LSUBF
SNOMLT = EX * DT
DT - TIMESTEP (SEC)
FLX3 - PHASE-CHANGE HEAT FLUX FROM SNOWMELT (W M-2)
FLX1 - PRECIP-SNOW SFC (W M-2)
FDOWN - Radiation forcing at the surface (W m-2)
SSOIL - SOIL HEAT FLUX (W M-2)
I am studying the melting of snow cover over the coast of West Antarctica. In an attempt to find a heat source of melting during the case study I discovered that it was mainly produced by “Freezing rain latent heat flux” (variable FLX2) as an uncompensated part of surface heat budget.
In my opinion Freezing rain latent heat flux may release only when air temperature or at least ground temperature is below 0 and never can produce additional melting at the current moment, isn’t it? But it looks like the LSM model does not divide the region into already warm, wet snow cover and really frozen surface at higher altitudes. As a result, a huge melting and runoff (SFROFF) was obtained during the rain episode. 2m air temperature (T2) was +2C and Surface skin temperature (TSK) = 0C. It can be noticed on the attached figure around 39 time step.
I wouldn't be surprised if I missed some settings or input for this to work correctly.
The corresponding equation chain from phys/module_sf_noahlsm.F :
FLX3 = FDOWN - FLX1- FLX2- EMISSI*SIGMA * T14- SSOIL - SEH - ETANRG
EX = FLX3*0.001/ LSUBF
SNOMLT = EX * DT
DT - TIMESTEP (SEC)
FLX3 - PHASE-CHANGE HEAT FLUX FROM SNOWMELT (W M-2)
FLX1 - PRECIP-SNOW SFC (W M-2)
FDOWN - Radiation forcing at the surface (W m-2)
SSOIL - SOIL HEAT FLUX (W M-2)
