Simulated SWOT Sea Surface Height products

Contents: Simulated SWOT Sea Surface Height products KaRIn and Nadir.

DOI: 10.24400/527896/a01-2021.006   -  more metadata

Variables of Level-2 Low Rate (LR) data (L2_LR_SSH)

For the KaRIn products, the following variables are filled (the others are at default values): 

• ssh_karin (= GLORYS simulated+ Errors simulated),
• ssha_karin (= ssh_karin - mean of GLORYS maps over the period),
• ssh_karin_2 (= ssh_karin),
• ssha_karin_2 (= ssha_karin),
• ssha_karin_qual,
• distance_to_coast,
• ancillary_surface_classification_flag,
• dynamic_ice_flag,
• cross_track_distance,
• mean_sea_surface_cnescls,
• mean_sea_surface_cnescls_uncert,
• geoid,
• depth_or_elevation,
• internal_tide_hret (only for GLORYS),
• internal_tide_sol2 (only for GLORYS),
• ocean_tide_fes (only for MITgcm),
• dac (only for MITgcm),
• ice_conc.

The following variables are simulated by the CNES/JPL Simulator : https://github.com/CNES/swot_simulator 

• simulated_true_ssh_karin (ssh_karin - Errors simulated),
• simulated_error_baseline_dilation,
• simulated_error_timing,
• simulated_error_roll,
• simulated_error_phase,
• simulated_error_orbital,
• simulated_error_karin.

Variables for the Level-2 and Level-3 corrected SSH datasets

The following variables are provided: 

• height_cor_xover: Height correction from KaRIn crossover calibration. See Dibarboure et al., June 2022, SWOT Science Team meeting, "SWOT simulated Level-2 and Level-3 data-driven calibration" for more details on the calibration process. This correction is already applied to the SSH kaRin by adding its value.
• simulated_errors: This is derived from a simulation using the most faithful pre-launch error scenario (Current Best Estimates 2021). It contains the sum of the various systematic errors identified (attitude knowledge, interferometric phase, KaRIn mast length imprecision), details are described in Dibarboure et al., 2022.
• ssh_karin: Corrected SSH kaRin. SSH kaRin containing the simulated errors and the crossover calibration. This SSH also contains a Wet Tropospheric error simulation and a white noise simulation for the KaRIn instrument.
  ssh_karin = (true_ssh + wet_tropo_err + karin_instrumental_noise) + simulated_errors + height_cor_xover.

Use: geophysical studies, oceanography, may be of limited use over other surfaces. Studies performing simulation measurements.

Geographic coverage: Global. The data from the KaRIn swath are spanning 60km on both sides of nadir with a nadir gap. All the variables are given on a swath-aligned 2x2 km² grid and sea surface Height on a 250x250 m² native grid. 

Data access service: download here. Note that L2_LR_SSH products are also distributed by PODAAC/JPL here.

Condition of use: No condition is required to get access to the data

Format: NetCDF

References:

• Dibarboure et al., June 2022, SWOT Science Team meeting, "SWOT simulated Level-2 and Level-3 data-driven calibration" 
• Dibarboure.G., Ubelmann.C., Flamant.B., Briol.F., Peral.E., Bracher.G., Vergara.O. , Faugère.Y., Soulat.F., and Picot.N. (2022): Data-driven calibration algorithm and pre-launch performance simulations for the SWOT mission. (submitted to Remote Sensing)

User manual:  SWOT product description for L2_LR_SSH products

Copyright: 2011-2012 and 2014-2015 Cnes