If one sampled every 4 hours in a typical longshore upwelling flow regime 



of 30 cm sec" to resolve this process, at least 5 ships would be required 



every 20 km for the necessary biomass measurements (Kelley, 1976). To 



date, the closest realization of this sampling requirement was the Fladen 



Ground Experiment (FLEX), which involved sequential deployment of ~20 



2 

 ships for 100 days over a 10 km area. Extending such synoptic biomass 



measurements beyond the ship domain could serve as one definition of what 



is meant by remote sensing. Some biomass measurements previously made on a 



ship, for example, can now be made by buoys, but a combination of buoys and 



one ship, or even a fleet, cannot duplicate areal coverage by aircraft and 



satellites. In many respects, however, these different platforms collect 



mutually exclusive, but complementary data sets, all of which are required 



to properly assess the fate of shelf production. 



2.2 SATELLITE REMOTE SENSING 



The Coastal Zone Color Scanner (CZCS) on the Nimbus-7 satellite is the only 

 satellite sensor in orbit (Table 2-2) for the purpose of assessing marine 

 biomass (Hovis et al., 1980; Gordon et al., 1980). The CZCS was specifi- 

 cally designed to detect upwelling radiance in spectral bands selected for 

 the purpose of detecting variations in the concentrations of phytoplankton 

 pigments. The theoretical and experimental techniques for describing the 

 bio-optical state of ocean waters and its relationship to optical para- 

 meters that can be remotely sensed have been discussed by a number of 

 workers (Morel and Prieur, 1977; Smith and Baker, 1978a, b; Baker and Smith, 

 1981). 



Simply stated, the CZCS radiance data can be utilized to estimate ocean 

 chlorophyll concentrations by detecting shifts in sea color, particularly 

 in oceanic waters. Clear open ocean waters have low chlorophyll concentra- 

 tions (0.01-1.0 yg chl £ " ) and the solar radiation reflected from the 

 upper layers of these waters is blue; conversely, waters with high concen- 

 trations of chlorophyll (>1.0 yg chl i~ ) are green (Morel and Smith, 

 1974). It has been demonstrated that this change in ocean color can 

 provide a quantitative estimate of chlorophyll concentration (Gordon and 

 Clark, 1980; Smith and Baker, 1981) for oceanic regions with an accuracy of 

 0.3 to 0.5 log C (where C is the chlorophyll concentration). 



2-4 



