Skip to main content
U.S. flag

An official website of the United States government

Calibration/Validation Test Sites

This collection of test sites provides critical information on the post launch characterization and calibration of space-based optical imaging sensors to assist the global science community in providing more accurate land/climate studies.(1972 to present).

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:

Calibration/Validation Instrumented test sites to obtain radiometric information
Dome C, AntarcticaDunhuang, China, AsiaFrenchman Flat, NV, USA, North AmericaIvanpah Playa, NV/CA, USA, North AmericaLa Crau, France, EuropeNegev, Southern Israel, AsiaRailroad Valley Playa, NV, USA, North AmericaTuz Golu, Turkey, Asia(Public domain)

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:

Calibration/Validation Pseudo-invariant test sites
Libya 4Mauritania 1 & 2Algeria 3Libya 1Algeria 5(Public domain)

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:

Additional Information

Access Data

EarthExplorer can be used to search, preview, and download Calibration/Validation Test Sites. The collection are located under the Calibration Dataset.

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