Sea-Viewing Wide Field-of-View Sensor (SeaWiFS)
|Sensor/Satellite||Agency||Mission Duration||Swath||Resolution||Bands||Spectral Coverage (nm)|
|SeaWiFS||NASA (USA)||1997-2010||2,806 km||1,100 m||8||402-885|
The SeaWiFS mission was launched by the Orbital Sciences Corporation in 1997. It was a medium-spectral resolution imaging spectroradiometer operating in the visible to near-infrared spectral range, aboard the polar sun-synchronous OrbView-2 (OV-2) satellite. The sensor collected data in eight spectral bands (see Chapter 4; Table 4.5) from 402 to 885 nm. The instrument tilted ±20 degrees to minimize sun glint.
SeaWiFS mission used MOBY water-leaving radiances for the vicarious calibration and near-monthly lunar looks to track spectral band degradation over time. The mission included an extensive calibration/validation program using global in situ measurements for product validation.
Data can be freely and openly accessed.1 Global data are freely distributed at Level 1 (TOA total radiances in eight bands), Level 2 (geophysical products such as the spectral marine reflectances and the chlorophyll concentration), and Level 3 (global gridded products).
The NASA Ocean Color Group distributes the following products, which are used for a large array of applications described in Chapter 2:
Radiances at 412, 443, 490, 555, 670 nm; aerosol optical thickness at 865 nm; epsilon of aerosol correction at 765 and 865 nm; OC4 Chlorophyll a concentration; diffuse attenuation coefficient at 490 nm; Angstrom coefficient, 510-865 nm; Photosynthetically Active Radiation from the sun 400-700 nm; Normalized Difference Vegetation Index; Land Reflectance and a SeaWiFS Biosphere product.
|Sensor/Satellite||Agency||Launch Date||Swath (km)||Resolution (m)||Bands||Spectral Coverage (nm)|
|GLI/ADEOS II||NASDA (Japan)||2002-2003||1,600||250/1,000||36||375-12,500|
The Global Imager (GLI) was launched in 2002 aboard ADEOS II, which also carried POLDER-2 [Polarization and Directionality of the Earth’s Reflectances]. GLI is designed to provide frequent global observations of reflected radiance of the ocean, clouds, and land. The sensor has a multi-spectral observation capability with 36 bands and ground resolution of 1 km. Some channels have a resolution of 250 m.
Vicarious calibration was performed. Results of vicarious calibration workshop are available online.2
Data products are available online.3
Ocean color, water-leaving radiances and aerosols.