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

Sensor Description:

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.

Calibration:

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 Availability:

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).

Applications:

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.

GLI

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

Sensor Description:

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.

Calibration:

Vicarious calibration was performed. Results of vicarious calibration workshop are available online.2

Data Availability:

Data products are available online.3

Applications:

Ocean color, water-leaving radiances and aerosols.

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1 See http://oceancolor.gsfc.nasa.gov/.

2 See http://suzaku.eorc.jaxa.jp/GLI/cal/index.html; accessed October 25, 2010.

3 See http://www.eorc.jaxa.jp.



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