to evolve over time scales of order a few weeks to a month, i.e., at the 

 probable CZCS time scale. Considering these scales and CZCS sampling 

 characteristics together, long-term global sampling with a CZCS-type 

 instrument can adequately resolve synoptic-scale phytoplankton standing 

 stock distributions, while higher frequency data gaps could be covered 

 within the five specific shelf areas by CZCS in situ instrumentation 

 (Table 4-2) and judicious use of ships and aircraft. 



4.5 ADDITIONAL OCEANIC STUDIES 



Oceanic systems are more tractable than shelf systems for understanding 

 certain aspects of biological-physical coupling because they are freed 

 from some of the high-frequency fluctuations of coastal systems (Walsh, 

 1976), from effects of local bottom topography, and from complex color 

 patterns produced by river-borne organics and suspended sediments. 

 Because of these simplifications compared to coastal regions and the 

 more reasonable expectation of isotropy in the background signals of 

 oceanic systems, oceanic regions are logical natural laboratories for 

 investigation of selected biological and physical processes. Eddies, 

 for example, are relatively easily tracked over the open ocean in 

 studies of eddy formation and evolution. Frontal evolution similarly 

 may be more easily followed than near-shore phenomena. Areas homogeneous 

 in space are logical regions in which to monitor evolution in time. 



The upcoming ODEX (Optical Dynamics Experiment) study, for example, will 

 evaluate the effects of autumn mixing on oceanic optical properties. A 

 site has been selected between Hawaii and San Diego to exclude major 

 advective "noise" from its time-course "signal." The primary goal of 

 ODEX is to develop and field test a two-dimensional physical-biological 

 optical model of the upper ocean that predicts the diffuse attenuation 

 coefficient, K(Z, t, X ), in those regions where advective effects are 

 small. (Here, two dimensions mean depth and time.) Additional goals 

 are to assess the feasibility of a four-dimensional model (x, y, z, and 

 time) and to predict other optical properties such as spectral beam 

 attenuation and the volume scattering function. 



4-17 



