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Calibration/Validation Test Sites

Earth surfaces with suitable characteristics have long served as test sites to verify the post launch radiometric calibration performance of satellite sensors. The U.S. Geological Survey (USGS), as a supporting member of the Committee on Earth Observation Satellites (CEOS) and the Global Earth Observation System of Systems (GEOSS), has established an online catalog of prime candidate test sites for the post launch characterization and calibration of space-based optical imaging sensors. The online catalog can be accessed at

The CEOS Infrared and Visible Optical Sensors (IVOS) subgroup members established a set of CEOS-endorsed globally distributed reference standard test sites. There are eight instrumented sites and five pseudo-invariant test sites.

The instrumented sites are primarily used for field campaigns to obtain radiometric information. These sites serve as a focus for international efforts, facilitating traceability and cross-comparison to evaluate biases of in-flight and future sensors in a harmonized manner.

Instrumented test sites:

Dome C, Antarctica
Dunhuang, China, Asia
Frenchman Flat, NV, USA, North America
Ivanpah Playa, NV/CA, USA, North America
La Crau, France, Europe
Negev, Southern Israel, Asia
Railroad Valley Playa, NV, USA, North America
Tuz Golu, Turkey, Asia


The pseudo-invariant desert sites were chosen because of their high reflectance and are composed mainly of sand dunes and areas with little, if any, vegetation. The pseudo-invariant reference standard test sites are used to evaluate the long-term stability of a sensor and to facilitate the cross-comparison of multiple sensors. They can also be used for the validation of higher-order climate variable products.

Pseudo-invariant test sites:

Libya 4
Mauritania 1 & 2
Algeria 3
Libya 1
Algeria 5

The USGS Earth Resources Observation and Science (EROS) Center Remote Sensing Technologies (RST) Project supports advanced instrumentation for sensor calibration and product validation. These properties include high-precision global positioning system (GPS) reference data, complete meteorological microclimate data, soil temperature and moisture data, surface solar radiation data, and carbon flux measurements. Without calibrated instruments, data products cannot be validated for science use; therefore, the instrument data are crucial.

Sensors used:

Landsat ETM+ (Enhanced Thematic Mapper Plus) -
SRTM (Shuttle Radar Topography Mission) -
Landsat MSS (Multispectral Scanner) -
Landsat TM (Thematic Mapper) -
EO-1 ALI (Advanced Land Imager) -
EO-1 Hyperion -

Additional information:

Data Use and Citation Policies

For information on how to cite USGS data plus guidance on usage restrictions,
please see our Data Citations and Use page at

Any use of trade, firm, or product names is for descriptive purposes only and
does not imply endorsement by the U.S. Government.

Contact Information for User Assistance

U.S. Geological Survey (USGS)
Earth Resources Observation and Science (EROS) Center
47914 252nd Street
Sioux Falls, SD 57198-0001

Phone Number: 605-594-6151
Toll Free: 800-252-4547
Fax: 605-594-6589


Business Hours: Monday thru Friday, 8:00 a.m. to 4:00 p.m., Central Time