wlwdown(i,j,bi,bj) = max(wlwdown(i,j,bi,bj),wlwdown0)
& wswflux0, wswdown0, wlwflux0, wlwdown0,
_RL wlwdown0
& wsnowprecip0, wlwflux0, wlwdown0, wevap0,
wlwdown0 = 0. _d 0