SCOOP project pages

SCOOP Data Pages: Second Test Data Set

The table below lists and provides further information on the different components of the SecondTest Data Set.

Data types and providers:

• Level 1B (L1B) ^[1]: isardSAT
• Level 2 (L2) ^[2]: isardSAT
• "Experimental" Coastal Data Set ^[3]: isardSAT
• Cuba Coastal Data Set ^[4]: isardSAT
• "Main" Phase 2 RDSAR ^[5]: TU Delft
• MLE4 RDSAR ^[6]: TU Delft
• Wet Troposphere Correction (WTC) ^[7]: University of Porto
• Auxiliary input data: Further information
• Validation data used for evaluation: Further information

The algorithms used to generate this data set are described in the L1 Algorithm Theoretical Basis Document (ATBD), the L2 Algorithm Theoretical Basis Document (ATBD), and the products are described in the Product Specification Document (PSD).

Login information for the SCOOP ftp server is available on request by email from scoop.info at esa.int.

Notes:

1. L1B products have been processed by isardSAT. Key aspects are:

• Zero-padding (factor 2) in range
• Intra-burst windowing (Hamming)
• Approximate beamforming (azimuth processing)
• Cut stack edges (restrict to look angles > -0.6° or < 0.6°)
• No intra-burst alignment

2. L2 products have been generated by isardSAT. Key aspects are:

• In-house isardSAT implementation of SAR ocean retracker (Ray et al. 2015)
• Adapted to L1B processing modifications(consistency L1B-L2).
• Fixed PTR settings (not SWH dependent), based on S3 IPF (azimuth PTR coefficient = 0.3831; range PTR coefficient = 0.513)
• Sigma0 bias applied

3. "Experimental" Coastal Data Set. A new isardSAT scheme was implemented that instead takes the first window delay of the first full ocean return as the reference, thus waveforms are aligned with respect to the first burst or look in the stack marked as ocean and not lost. This ocean decision is based on the rough ocean/land mask from the FBR at burst level. This data set was produced for internal assessment and validation, but because the analysis did not show an improvement on the existing SAR Mode Test data set (indeed performance was worse in some regions), it has not been made publicly available. The processing is described in Makhoul (2018) - Report to Acceptance Review.

4. Cuba Coastal Data Set. The isardSAT processing uses the MSS2 mean sea surface field in the product (MSS DTU15) to fix the initial position of the retracking point, and limits the waveform to a number of range bins around this point. The processing is described in Garcia (2018) - Report to Acceptance Review.

5. RDSAR products are processed by TU Delft from the Cryosat FBR Baseline C data set. The main processing chain remained the same for the RDSAR Test Data Set 2. The most recent corrections and models were applied, and the orbits updated to the GDRE standard (more information is available in the RADS4 manual (https://github.com/remko/rads).

6. Because of the uncertainties in the attitude information in the CryoSat products (Scagliola et al, 2018), a small data set using an MLE4 retracker was generated for SCOOP, covering the North Sea Region of Interest. This data set is also available on request.

7. The Wet Troposphere Correction, produced by the University of Porto, is the same as for TDS1. Reference M. Joana Fernandes and Clara Lazaro, GPD+ Wet Tropospheric Corrections for CryoSat-2 and GFO Altimetry Missions, Remote Sensing 2016, 8(10), 851; doi:10.3390/rs8100851 (http://www.mdpi.com/2072-4292/8/10/851)

8. The input data to the Second SCOOP Test Data Set are Cryosat-2 Full Bit Rate (FBR) data, Baseline C processing. These input data were retrieved for the project by ESA / ESRIN and provided to the project team on hard disk. They are not available through the project pages but can be accessed directly from ESA. The input files are listed by year in links.

9. Sentinel 3a (cycles 41 and 42) and Sentinel 3b (cycle 22 and 23) L1A closed loop tracking mode data from Feb-March 2019 were used as input for generating part of the Cuba Coastal Data set