Spaceborne instruments, designed to make precise measurements of ocean color,
are the best method available to estimate ocean productivity on the global
scale. In 1978, the Coastal Zone Color Scanner (CZCS) provided the first
remote-sensing data from Earth orbit concerning worldwide phytoplankton
distributions and patterns of surface productivity, yet the CZCS was only
an experimental mission that operated on a limited schedule.
After the failure of the CZCS in 1986, there were no other sources of ocean
color data from spaceborne sensors until 1996, when several new ocean color
instruments were placed into orbit. Even more orbiting ocean color sensors
are planned, and these instruments may finally provide the data necessary
to accurately quantify the global distribution and seasonal variability of
life in the oceans.
Coastal Zone Color Scanner (CZCS)
CZCS was an experimental ocean color instrument launched aboard NASA's NIMBUS-7 satellite.
It shared satellite resources and power with many other sensors, and therefore collected data only sporadically. Additionally,
fewer scenes were collected as the instrument aged. The data are used to study the regional and seasonal variation
in primary productivity, environmental change, oceanic features, and even outbreaks of infectious disease.
Data and more information are available from the Goddard DAAC's ocean color web site:
Ocean Color Data and Resources.
Modular Optoelectronic Scanner (MOS)
MOS is a sensor developed by the German Aerospace Research Establishment (DLR) Institute for Space
Sensor Technology. The specific goals of MOS include improved (compared to CZCS) corrections for atmospheric, sea surface, and
turbidity effects. MOS data will also be correlated with SeaWiFS data.
Two MOS instruments have been launched, one aboard the Indian Remote Sensing Satellite (IRS) P3, and the other in the Russian
Priroda module, a component of the Mir space station. The IRS MOS has an extra channel, used to enhance determination of surface roughness. Data collection is limited to
ground stations, and therefore does not provide global coverage.
More information is available from: http://www.ioccg.org/reports/mos/mos.html.
Ocean Color and Temperature Scanner (OCTS)
OCTS was an instrument aboard Japan's Advanced Earth Observing Satellite (ADEOS). It collected
chlorophyll and sea-surface temperature data. High resolution and low resolution data were transmitted separately. Global coverage was
achieved by OCTS every 3 days, which provided information on rapidly changing phenomena. ADEOS was lost on June 30, 1997. Data available
through Japan Aerospace Exploration Agency (JAXA.)
Sea-viewing Wide Field-of-view Sensor (SeaWiFS)
SeaWiFS is an ongoing ocean color mission operated by Orbital Sciences Corporation (OSC) for NASA. SeaWiFS data is being
used to help clarify the magnitude and variability of chlorophyll and primary production by marine phytoplankton. In particular, the data will help determine the
distribution and timing of 'spring blooms' - the rapid increase in
phytoplankton populations stimulated by increasing light availability and
higher nutrient concentrations characteristic of the spring season.
More information is available from the SeaWiFS Project homepage.
Data is being distributed by the Goddard DAAC.
Ocean Color Imager (OCI)
The OCI will be launched by Taiwan aboard the first Republic of China Satellite (ROCSAT-1).
Its orbit will only be inclined 35°, limiting coverage to the tropics. Data will be available from the
OCI Science Data Distribution Center.
Moderate Resolution Imaging Spectroradiometer (MODIS)
MODIS is an instrument that will orbit aboard the Earth Observing System (EOS) AM and PM series of satellites, resulting in 15
years of continuous ocean color data. It will also sense sea-surface temperature. Hardware and algorithm improvements will result in data that are more
accurate than either CZCS or SeaWiFS. Data will be distributed by EOSDIS.
Global Imager (GLI)
The GLI is a successor to the OCTS aboard Japan's ADEOS. It will be flown on ADEOS II.
More information can be found on NASDA's Global Imager page.
Medium Resolution Imaging Spectrometer (MERIS)
MERIS will be launched on ESA's ENVISAT-1.
Low Resolution Camera
The Low Resolution Camera will be aboard the Korea Multi-Purpose Satellite (KOMPSAT). It will have six bands
programmable from the ground, and will be able to conduct studies of both ocean and land.
|
Comparison of Ocean Color Instruments |
Instrument |
Satellite |
Dates of Operation |
Spatial Resolution |
Swath Width |
CZCS |
Nimbus-7 |
10/24/78-
6/22/86 |
825 m |
1556 km |
MOS |
IRS P3 |
3/18/96- |
520 m |
200 km |
MOS |
Priroda |
4/23/96- |
650 m |
85 km |
OCTS |
ADEOS |
8/17/96- |
700 m |
1400 km |
SeaWiFS |
SeaStar |
scheduled 5/97 |
1100 m |
2800 km |
OCI |
ROCSAT-1 |
scheduled 4/98 |
800 m |
690 km |
MODIS |
EOS AM-1 |
scheduled 6/98 |
1000 m |
2330 km |
GLI |
ADEOS-2 |
scheduled 2/99 |
1000 m |
1600 km |
MERIS |
ENVISAT-1 |
scheduled 7/99 |
1200 m |
1450 km |
Low Resolution Camera |
KOMPSAT |
scheduled 1999 |
1000 m |
800 km |
Comparison of Wavelength & Bandwidth
for
Spaceborne Ocean Color Instruments
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