Sentinel-6 (Jason-CS) Poseidon4: Test data examples for Users

Marco Fornari (ESA/ESTEC, Netherlands)


Rob Cullen (ESA/ESTEC, The Netherlands); Mònica Roca (isardSAT, Catalonia)

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: Instrument Processing: Measurement and retracking (SAR and LRM)

Presentation type: Type Poster

Sentinel-6 (Jason-CS) will fulfill the objectives of continuing the long-term retrieval of global sea level rise/variability in addition to providing NRT geophysical parameter data, such as wind speed, to operational users. It will follow ocean surface topography reference missions since 1992 and provide improved geophysical parameter retrievals as a result of the use of new technology combined with experience of ESA/CryoSat data over ocean. The result benefits operational and science oceanographic communities with the state of the art in design and will secure optimal operational and science data return in the long term.
As part of the development Phase B1, the satellite prime contractor was requested to develop a Ground Processor Prototype (GPP) for the Jason-CS Poseidon-4 based on the SRAL baseline instrument. The baseline Poseidon-4 design has evolved significantly during the phases B1 and B2 as a result of instrument obsolescence mitigation and necessary improvements needed to meet mission level performances that have evolved since Jason-2 and -3.
The current baseline for the Poseidon-4 instrument includes the so-called 'interleaved mode' that provides simultaneously on-board-computed classical pulse-limited waveforms (in line with previous reference missions) and allow SAR processing on-ground. In addition to the raw SAR data, an on-board processing has been added to the SAR mode in order to reduce overall data volume: the Range Migration correction (RMC) processing that will be the baseline data for open ocean. As a result, the Poseidon-4 is capable of generating 3 different data streams: LRM, SAR and RMC.
ESA developed an instrument simulator capable of generating Poseidon-4 instrument source packets in the 3 above modes. The simulator will evolve with the instrument development.
The Poseidon-4 GPP has the functionality of processing the Poseidon-4 instrument source packets (ISPs) up to L1b. More in details, ESA defined the following 4 L1 netCDF products for the P4 GPP:
1. L1A SAR: Geo-located bursts of Ku echoes. All calibrations are applied. Each Ku record contains 1 SAR burst of calibrated and aligned echoes.
2. L1B-S SAR: Fully processed and calibrated SAR complex echoes, arranged in stacks after slant range correction and prior to echo multi-look.
3. L1B SAR: Fully calibrated multi-looked power echoes.
4. L1B LRM: Fully calibrated pulse limited power echoes.
At the end of summer 2014, ESA is planning to deliver some P4 simulations over ocean, processed by the P4 GPP in the 4 L1 products specified above.
This poster will provide:
- An overview of the simulations, describing the ocean surface characteristics for each one.
- An overview of the 4 L1 products, showing the differences between modes and products levels.
Marco Fornari