The vertical distribution of the net radiation budget within a spruce forest in summer

Abstract

In order to investigate the vertical distribution of the terms of the net radiation budget on clear summer days an experiment was carried out in the Ebersberger Forst, a spruce forest near Munich. For that purpose three stationary radiation measuring systems were set up in 2 m above the forest floor, within the canopy, and at the tree top level. Global radiation, reflected shortwave radiation, and net allwave radiation were directly measured at each site. In addition vertically detailed measurements were made with an albedometer mounted at a lift. Besides the vertical profiles of the most radiation flux densities the results show clearly that in coniferous forests with a stand geometry comparable to that of the Ebersberger Forst more than 60% of the global radiation at the tree top is available within the upper canopy for the transformation in other energies, mainly latent heat.