The altimeter product suite for the Sentinel-6/Jason-CS mission

Remko Scharroo (EUMETSAT, Germany)

CoAuthors

Carolina Nogueira Loddo (EUMETSAT, Germany); Cristina Martin-Puig (EUMETSAT, Germany)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Outreach, Education and Altimetric Data Services

Presentation type: Type Oral

The Sentinel-6 (Jason-CS) mission will follow TOPEX and the Jason-series of “reference altimeter missions”. But it is in many ways a totally new type of mission, a different platform (similar to CryoSat) and a different altimeter (dissimilar from any of the previous altimeters). Not only will it be the first Synthetic Aperture Radar (SAR) altimeter used on one of the reference missions, it will also be the first altimeter that operates in a continuous high-rate pulse mode, 100% of the time. This particular operating mode allows simultaneous production of Low Resolution (LR) mode measurements on-board as well as the processing of SAR echoes (High Resolution, HR, processing) on-ground. Both types of measurements will be provided in (separate) Sentinel-6 altimeter data products.

Sentinel-6 will bring some unique opportunities for cross-calibrating and cross-validating LR and HR altimetry, housed on the same platform, working from the same altimeter echoes, just using different processing techniques. Also, it will be the first time that we will be able to fully process on-ground 100% of the echoes that would otherwise be averaged on-board. This presentation will show how this is reflected in the Sentinel-6 products, how these compare with the products of the Jason-series and of Sentinel-3 and how continuity is ensured. Particular emphasis will be on highlighting the Level 1A (L1A) and Level 1B (L1B) product content.

Level 1 products will be made available containing all the individual echoes in the time domain (L1A) or the measurement data and waveforms without geophysical corrections (L1B). A L1B-S product (with the individual waveforms stacked and geo-located such as is available for Sentinel-3) can be derived from the L1A after performing Delay Doppler processing. Although L1B-S is not part of the product line, a tool will be provided to the users so that they can process L1A to L1B-S.

Level 2 (L2) products will contain the geophysical measurements of sea level, wind speed, and significant wave height, at 20-Hz and 1-Hz, from both LRM and SAR altimetry. They will also contain an appropriate set of geophysical corrections, outlined in this presentation, aimed at providing sea level measurements at the cutting edge of what is feasible. In numerous cases alternatives are provided to support various applications and error assessment. The L2 products can be easily aligned with the L1B products (and vice versa) in order to combine waveforms and geophysical corrections and retrievals. Sentinel-6 will be the first altimeter mission to provide Level 2 radiometer products at its original posting rate alongside the altimeter products.

Around the time of the OSTST meeting, test datasets will be made available to users, who will be invited to provide feedback on the content, applicability, and format. The presentation will show highlight some of these.
 

Oral presentation show times:

RoomStart DateEnd Date
Symphony II Tue, Oct 24 2017,14:00 Tue, Oct 24 2017,14:15
Remko Scharroo
EUMETSAT
Germany
remko.scharroo@eumetsat.int