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Sentinel 3A Synthetic Aperture Radar Altimeter (SRAL) Level 2 Land data

Update Frequency: Continual
Latest Data Update: 2017-05-25
Status: Ongoing
Online Status: ONLINE
Publication State: Preview
Publication Date:


This dataset contains altimetry data from the Synthetic Aperture Radar Altimeter (SRAL) aboard the European Space Agency (ESA) Sentinel 3A Satellite. Sentinel 3A was launched on the 16th February 2016. Level-2 (L2) is the Level-1 data corrected for geophysical effects.

Like many recent altimeters, Sentinel 3 operates at two frequencies (Ju and C band) in order to derive an ionospheric correction. A Level 2 SRAL/MWR complete product contains three data files:
a "reduced" (Red) data file, containing a subset of the main 1 Hz Ku band parameters
a "standard" (Std) data file containing the standard 1 Hz and 20 Hz Ku and C-band parameters
an "enhanced" (Enh) data file containing the standard 1 Hz and 20 Hz Ku and C-band parameters, the waveforms and the associated parameters necessary to reprocess the data.
The SRAL/MWR Level-2 products are generated in Standard Archive Format for Europe (SAFE) format. All the information relevant to the product is gathered into a single package. Inside this package, the specific objects containing measurement data are encoded in netCDF format.

There are different levels of data latency related to the availability of auxiliary or ancillary data:

Near Real-Time (NRT): delivered less than 3 hours after data acquisition
Slow Time Critical (STC): delivered within 48 hours after data acquisition
Non-Time Critical (NTC): delivered within typically 1 month after data acquisition.

Data are provided by ESA and are made available via CEDA to any registered user.

Citable as:  [ PROVISIONAL ] Copernicus; European Space Agency (9999): Sentinel 3A Synthetic Aperture Radar Altimeter (SRAL) Level 2 Land data. NERC EDS Centre for Environmental Data Analysis, date of citation.
Abbreviation: Not defined
Keywords: Sentinel, Synthetic Aperture Radar Altimeter, SRAL


Previous Info:
No news update for this record
Previously used record identifiers:
No related previous identifiers.
Access rules:
Public data: access to these data is available to both registered and non-registered users.
Use of these data is covered by the following licence: When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record.
Data lineage:

Data collected and prepared by European Space Agency (ESA). Downloaded from the Sentinel hubs for use by the CEDA community.

Data Quality:
Data provided by ESA. CEDA download the data from the Collaborative or open access data hubs to make available on the CEDA archive.
File Format:
These data are provided in NetCDF format

Process overview

This dataset was generated by a combination of instruments deployed on platforms and computations as detailed below.

Instrument/Platform pairings

Sentinel 3 Synthetic Aperture Radar Altimeter (SRAL) Deployed on: Sentinel 3A

Computation Element: 1

Title Computation Component: Level 2 Land processing algorithm applied to Sentinel 3 SRAL raw data.
Abstract There are three main steps in the Level-2 processing chain: 1. Compute time-derived geophysical/environmental parameters. 2. Perform re-tracking and compute physical parameters. 3. Compute Level-2 altimeter/radiometer geophysical processing. Computing time-derived geophysical parameters involves: * re-computing altitude, orbital altitude rate, location and Doppler correction, accounting for updated orbit data * computing ionospheric corrections *computing non-equilibrium and equilibrium ocean tide heights, tidal loading, solid earth tide height, equilibrium long period ocean tide height and pole tide height (using pole locations) *computing the height of the mean sea surface above the reference ellipsoid *computing the mean dynamic topography, the height of the geoid and the ocean depth/land elevation. Performing retracking and computing physical parameters (both SAR and LRM modes) involves: *discriminating echoes (ocean/lead, sea-ice, ice sheet margin or ocean/coastal) *performing retracking (ocean/lead, sea-ice, ice sheet margin or ocean/coastal) *computing physical parameters *merging snow depth (ocean/lead and sea-ice only) *performing a short-arc, along track ocean interpolation (ocean/lead and sea-ice only) *estimating freeboards (ocean/lead and sea-ice only) *performing a latitude limit check (ocean/lead and sea-ice only) (For SAR mode) performing modified slope correction (ice sheet margin and ocean/coastal only). Level-2 altimeter/radiometer geophysical processing involves: *inputting and checking Level-1 MWR products *computing and correcting physical parameters according to platform data *interpolating MWR data and computing MWR geophysical parameters *computing altimeter wind speed and rain/ice flags *computing wind, tropospheric corrections and inverted barometer according to meteorological data *computing HF fluctuations of the atmospheric effect on the surface (dynamic atmosphere correction) *computing sea state bias *computing dual frequency ionospheric corrections *building and checking Level-2 SRAL/MWR products.
Input Description None
Output Description None
Software Reference None
Output Description


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