Does SLUCM urban model conserve the energy?

[jan1203]

If I consider the radiation balance equation, I can compute the net radiation flux of surface from model outputs as
Q* = SWDNB - SWUPB + LWDNB - LWUPB
and the SUM (thermal balance of surface) should be 0 (the thermal flux into ground is defined as negative)
SUM = Q* + GRDFLX - HFX - LH
that is true for almost grid-points with a small residuum (~1W/m2), close to NOAHRES variable. But the problem is with grid-points containing urban LU when SLUCM is used, because there is the SUM sometimes with the residuum of several tens of W/m2. So my question is: Does SLUCM conserve the energy fluxes, or some variables (such as SWUPB and LWUPB) are not valid for urban LU?
Thanks, Jan

 

[Ming Chen]

Jan,
The surface radiation is recalculated in urban models. If you look at the code "module_sf_urban.F", you will find the variables SSG,SSGD,etc, which are direct and diffusive radiation on flat surface. They are passed into the subroutine "urban" through the driver "module_sf_noahdrv.F". Radiation balance is then recalculated in the urban module. For more details, please take a look at the code.

Ming Chen