The calval website acts as a portal to data from certain field sites used by scientists at JPL for calibration and validation activities related to:

• Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)
• Moderate Resolution Imaging Spectroradiometer (MODIS)
  
• Landsat (5,7,8,9)
• Along Track Scanning Radiometers (ATSR, ATSR2, AATSR)
• MODIS/ASTER Airborne Simulator (MASTER) and NASA Ames Research Partners

These activities include the validation of  the absolute radiometric calibration of the systems and surface geophysical products derived from the sensor data such as reflectance, temperature and emissivity. The goal is for all the measurements acquired at the validation sites to be made autonomously with the data regularly telemetered back to JPL and made available over the Web. Currently there are three sites in the US and one overseas at:

US Based Sites

Lake Tahoe CA/NV (https://laketahoe.jpl.nasa.gov)

Salton Sea CA (https://saltonsea.jpl.nasa.gov)

Russell Ranch, Davis CA (https://russellranch.jpl.nasa.gov)

Overseas Sites

Réserve Naturelle des Coussouls de Crau, France (https://calval.jpl.nasa.gov/lacrau)

Science Platform at "Acqua Alta Oceanographic Tower". Venice, Italy (https://calval.jpl.nasa.gov/venice)

The sites have been selected to provide a range of conditions. Together the Lake Tahoe and Salton Sea sites provide water temperatures ranging from 4C-35C.