PHOTOSYNTHETIC CLIMATE IN SELECTED REGIONS DURING THE NORTHERN-HEMISPHERE GROWING-SEASON

The feasibility of deriving photosynthetically active radiation (PAR) from satellite observations on global scale was previously demonstrate d (Pinker and Laszlo, 1992). The methodology used was evaluated agains t available ground truth (Pinker et al., 1993). The objective of this study was to provide, for a first time, consistent information on the temporal and spatial variability in PAR on a continental scale during a growing season; such information can be used to develop new paramete rizations of net primary productivity and evapotranspiration, that til l now were not possible.