and adjusting S(x,x ) in the visible accordingly. For turbid coastal 

 waters, for which L (670) f 0, the addition of both of these bands would 

 also facilitate correction. The minimal set of bands suggested for the 

 Ocean Color Imager are: 443nm, 520nm, 560nm, 670nm, 765nm, and 865nm. The 

 visible bands should be 20nm wide and the I.R. bands 50nm wide. In 

 addition, spectral bands at 490nm and 590 nm could be valuable in the 

 retrieval of C in the coastal regime. Also, it is expected that some fine- 

 tuning of the precise positions of the above bands will be necessary. 



These changes together with several minor modifications will result in a 

 system that will provide data from which global oceanic chlorophyll maps 

 with a resolution of a few kilometers can be generated. 



A. 2 ANCILLARY INSTRUMENTS 



Perhaps the most important ancillary satellite sensor for shelf primary 

 productivity studies is the Advanced Very High Resolution Radiometer 

 (AVHRR), an improved VHRR infrared radiometer. It is part of the standard 

 complement of sensors presently flown on the NOAA series of polar-orbitinq 

 environmental satellites on which the OCI is a candidate for inclusion. It 

 can provide sea surface temperature with an accuracy of about 0.6°C if no 

 clouds contaminate the field of view, and if atmospheric effects are 

 carefully removed. Horizontal temperature gradients of about 0.2 C can 

 also be resolved. Acquiring such data concurrently with ocean color 

 measurements will allow upwelling and frontal processes to be more 

 accurately described and will help in identifying certain water masses and 

 in locating boundaries of currents. 



Two other satellite sensors which could be flying in the same time frame as 

 the OCI are the altimeter and the scatterometer. Using a highly accurate 

 altimeter (nadir radar with +2 cm precision) on a satelite with a well- 

 known orbit allows the measurement of major surface current velocities; 

 with an accurate geoid, slower currents (especially their variability) can 

 be determined. Surface current measurements can be made by altimetric 

 determinations of the slope of the sea surface since the slope increases 

 with the speed of the current. Thus, with the TOPEX (dynamic TOPographv 

 Experiment) satellite (see Wunsch, 1981), the current field will be better 



A-4 



