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About RA-2

RA-2 map, hurricane Frances
RA-2 map - Upper ocean thermal conditions during hurricane Frances

Radar Altimeter 2 (RA-2) was an instrument on board the Envisat satellite, which determined the two-way delay of the radar echo from Earth's surface to a very high precision: less than a nanosecond. It also measured the power and the shape of the reflected radar pulses.

The RA-2 instrument was a dual-frequency, nadir-pointing, pulse-limited radar operating at 13.575 GHz (Ku-band) and 3.2 GHz (S-Band) using a single antenna dish and was based on the heritage of the ERS-1 RA. It was designed to operate autonomously and without interruption over all surfaces: ocean, land and ice. RA-2 was the first high-latitude altimeter that aimed to improve the precision of previous altimeters over open oceans (ERS satellites), enhancing operations over ice sheets.

Data Description

All Envisat RA-2 products, in accordance with ESA Earth Observation Data Policy, are freely available to registered users via FTP. Read more about the available products and the registration process which is required to access them:

Data Tools

The Broadview Radar Altimetry Toolbox (BRAT) tool can be used to visualise and process RA-2 data. It is an extensive tutorial on what is altimetry, techniques used and examples of usage of data; plus software to read, process and visualise altimetry data.

RA-2 Cal/Val

The goal of RA-2 calibration and validation activities was to verify the accuracy and quality of data the instrument acquired. The RA-2 Cal/Val Plan, Calibration Activities and Validation Activities are available.

RA-2 Quality Control Reports

Quality Control is monitoring routinely the status of the spacecraft (payload and platform) and to check if the derived products meet the quality requirements along mission life-time. Daily and monthly reports are available for RA-2 quality monitoring.