The Copernicus Sentinel-3 Altimetry Land Thematic Products (TP) with Baseline Collection 005 (BC005) are currently under reprocessing to generate improved and tailored level-2 data for both Sentinel-3A and Sentinel-3B. The release of the level-2 TP’s will cover from the beginning of the mission up to date, and the new processing baseline will be then transferred in nominal operations to maintain a uniform processing baseline.

The reprocessing activities is performed by Telespazio (IT) in coordination with the Sentinel-3 Land Altimetry Mission Performance Cluster led by CLS (FR) and it is planned to complete by Q3 2023.

This article is periodically updated to report on the latest information on the reprocessing status of the S3 Land Altimetry level-2 Thematic Products, data availability and data validation.

Table 1: Reprocessing status, last update 20th April, 2023.

The following section describes the main updates introduced with the S3 Land Altimetry BC005 data products.

The data will be made available to the users once the validation process is completed.

ESA and the Sentinel-3 Land Altimetry Mission Performance Cluster (MPC) have recently developed dedicated delay-Doppler and level-2 processing chains for the generation of new Sentinel-3 STM Land level-2 products over (1) Inland Waters, (2) Sea Ice, and (3) Land Ice areas. The objectives of these so-called Thematic Instrument Processing Facilities (T-IPF) are to improve the performances of the current Sentinel-3 STM Land level-2 products and address the specific needs of the user communities for these three continental surfaces.

Compared to the current Sentinel-3 STM Land level-2 products, the content, and the format of the new T-IPFs L2 products have significantly evolved.

The delay-Doppler processing is now integrated into the level-2, while in previous baseline it was in the level-1. The main processing evolutions are:

• For Inland waters and Sea Ice: Hamming window and waveform zero-padding have been implemented in the delay-Doppler processing in SAR mode. Therefore, the number of waveform samples is now doubled compared to previous PB (currently 256 samples compared to 128 previously used).
• For Land Ice: The “extended-window” has been implemented in the delay-Doppler processing, to optimize the generation of SAR mode waveforms over rough and/or steeply sloping surfaces. The SAR mode waveforms over land ice are now centered around sample 44. In addition, the slope model used to relocate measurements at Point Of Closest Approach was also updated.
• The Sea Ice and Land Ice Thematic products have “equator-to-equator” coverage, while Inland-Water Thematic products remain “pole-to-pole” (for the start and end of the track in NetCDF files).

More information on the new thematic products is available at the following resources:

• Sentinel-3 SRAL/MWR User Handbook
• Sentinel-3 level-2 Product Data Format Specifications
• Product Notice on Sentinel-3 STM LAND Processing Baseline evolutions
• Sentinel-3 Land Altimetry Thematic Produsts (Baseline Collection 005) replaces present product types