es MESEARCH USERS' PANEL 
that significant changes occur over short periods of 
time (days to weeks) and over small distances (10 to 
100 km). In much the same way that meteorologists 
use Satellite data as input to models that predict the 
weather, oceanographers will input satellite- 
acquired measurements of ocean chlorophyll into 
computer simulation models to improve predictions 
of the state of ocean ecosystems and their effects 
on the biogeochemical cycles of carbon, nitrogen, 
phosphorus, sulfur, and oxygen. In both cases, sat- 
ellite data provide global coverage that is impracti- 
cal to obtain in any other manner. Thus, satellite- 
acquired ocean-color imagery is essential to the de- 
velopment and verification of accurate models that 
quantify the role of ocean biota in the major biogeo- 
chemical cycles — the key to understanding the glo- 
bal ecosystem. 
The acquisition of global ocean chlorophyll 
measurements from the CZCS instrument was an im- 
portant first step that moved the field of 
oceanography toward a new global perspective on 
the couplings between atmosphere and ocean and 
the special role of phytoplankton primary production 
in biogeochemical cycles. The acquisition of Sea- 
WiFS global data is essential if this new approach in 
oceanography is to develop and mature. 
Mission Support Science 
Scaling up from the present focus on small-scale 
studies of phytoplankton biomass (chlorophyll) distri- 
butions to the goal of providing global estimates of 
primary production in the 1990s will require ocean- 
color and sea-surface temperature data on a global 
scale. It will also require conducting the experi- 
ments necessary to understand the relationship of 
small-scale to basin-scale distributions. This subsec- 
tion briefly outlines a science plan for making the 
transition from small scale to ocean-basin and global 
scales. 
Three initiatives are proposed in the mission- 
support science plan for SeaWiFS. The first.is a se- 
quence of cooperative international studies using 
high-resolution ocean-color observations of an 
ocean basin to address stratified sampling issues. 
The second is an expanded effort to improve 
bio-optical relationships for the SeaWiFS band set 
and to develop and verify a physiologically based 
algorithm for productivity estimates. The third is 
to collect SeaWiFS observations globally and to 
composite them into moderate-resolution maps of 
pigment and primary productivity. 
Ocean Basin Study 
A detailed study of one ocean basin using 
SeaWiFS imagery and mooring and ship data is 
essential to bridge the gap from current applica- 
tions of CZCS imagery to ocean-basin scales. 
Physical processes, for the most part, control 
phytoplankton distribution and productivity, and, 
generally, physical processes at small scales are 
dominated by local wind-forcing and eddy-scale 
features. At the ocean-basin scale, global 
oceanic and atmospheric circulation patterns 
predominate, but eddies and local wind forcing 
significantly modify the overall pattern. The bio- 
logical consequences of basin-scale physical 
processes have not been studied. 
The GOFS and other international programs 
planned for the early 1990s will collect much of 
the essential data required to study ocean basin- 
scale primary productivity. What is needed is a 
focused effort, in collaboration with these pro- 
grams, to process both the high- and low- 
resolution SeaWiFS data for the North Atlantic, or 
another appropriate ocean basin, simultaneously 
with in-situ optical and biological measurements. 
This kind of multiplatform study would be an es- 
sential first step toward the goal of obtaining 
global-scale productivity estimates. 
Bio-Optical Modeling 
Spatial variability in primary production is cur- 
rently being investigated by means of satellite 
sensors. On the other hand, low-frequency 
(months to years) temporal variability at a given 
location is best investigated from moored arrays, 99 
