Fundamental Data Records (FDRs) and Thematic Data Records (TDR) from FDR4ALT project

In 2024, ESA has released the Altimetry Fundamental Data Record (FDR) derived from the ESA FDR4ALT project. This dataset is based on information gathered from the ERS-1, ERS-2 and ENVISAT missions and overcomes the individual mission datasets in various aspects.

The FDR4ALT initiative has encompassed the creation of Fundamental Data Records (Level 1 Altimeter and Radiometer data) and Thematic Data Records (Level 2 + geophysical products) within ESA's Heritage Space Programme.

The new records, available in NetCDF format, are derived from the ERS-1, ERS-2 and Envisat Altimeter and Radiometer instruments, spanning the mission archives from 1991 to 2012.

The new products, which demonstrate notable improvements (see the FDR4ALT Validation Report Document - FDR).

The records are aimed at different user communities and include the following datasets:

1. Fundamental Data Records for Altimetry
2. Fundamental Data Records for Radiometry
3. Atmospheric Thematic Data Product
4. Inland Waters Thematic Data Product
5. Land Ice Thematic Data Product
6. Ocean & Coastal Topography Thematic Data Product
7. Ocean Waves Thematic Data Product
8. Sea Ice Thematic Data Product

For more details visit the FDR4ALT project website.

RA2MWR Level 2 Reprocessing v3.0 data available

The ESA Envisat Altimetry Full Mission Reprocessing (FMR) was completed in 2018 with the generation of the V3.0 mission data set. This FMR follows the first Envisat Altimetry reprocessing Version (v2.1) completed in 2012.

There are two RA-2 Level 2 products: the Geophysical Data Record (GDR), the Sensor Geophysical Data Record (SGDR), both in netCDF format:

• GDR (Geophysical Data Record): Containing radar range and orbital altitude, wind speed, wave height, water vapour from the MWR and geophysical corrections.
• SGDR (Sensor and Geophysical Data Record): Which includes RA-2 geophysical data (as for GDR), plus RA-2 averaged waveforms (18 Hz) and RA-2 individual waveforms (1800 Hz).

The information provided in this page is applicable to the latest Altimetry V3.0 dataset (RA-2 and MWR) and to previous v2.1 dataset.

Even if the MWR data are acquired with a specific instrument, the processed data (Brightness temperatures and vapour/liquid water content) are not stored in a unique product, but are stored in the RA-2 products.

RA2MWR Level 2 Reprocessing v2.1

During the first reprocessing activity (Altimetry dataset v2.1) an anomaly within the Envisat MWR processing was identified. To correct for this anomaly a new calibration of the MWR Brightness Temperatures was performed and a new MWR Wet Tropospheric correction generated. The correction files are available for a limited period of ~6 months and delivered in NetCDF format.