ABSTRACT
Photosynthesis is virtually impossible to classify natural waters into depth layers or spatial regions that are populated by algae of predictable chlorophyllous pigmentation. The biological response of natural waters to impinging light, therefore, is clearly dependent upon not only the light spectrum of the incident radiation but also the populations of indigenous algal species and the temperature gradients defining the water column. Transfer the upwelling radiance spectrum recorded at the remote platform into the upwelling radiance spectrum that would be recorded at a remote platform located just above the water surface. Transport the upwelling radiance spectrum immediately above the water surface through the air-water interface and convert this spectrum into the volume reflectance spectrum that would be observed immediately below the air-water interface. To realistically evaluate photochemical and photobiological reactions occurring in natural water bodies, one must possess precise information regarding the actual energy density to which the chemical or biological component is exposed.
