flwupa=snow_emissivity*stefan*tsf**4
dflwupdT=4. _d 0*snow_emissivity*stefan*tsf**3
WRITE(iUnit,*) 'BlkF: snow_emissivity =',snow_emissivity
& snow_emissivity, ice_emissivity,
snow_emissivity = .98 _d 0
_RL snow_emissivity