Sentinel-3A MDB databases

This section provides a description of felyx generated match-up databases (MDB).

Sentinel-3 SLSTR MDB

Overview

The SLSTR MDB is operated at Ifremer within Ocean and Sea Ice SAF context. It combines multiple sources in the match-up.

The reference satellite product is Sentinel-3 level 2 WCT product, meaning the match-ups are primarily extracted from this dataset crossed with different in situ sources. Matching data from other Sentinel-3 datasets (level 1 RBT, level WST) or other datasets are then added to these match-ups. A match-up will then contain at least data fields from WCT and in situ input products. Fields from other datasets may or may not be present, depending on whether some matching data for these products could be found or not.

The in situ sources used are:

  • drifting buoys data from Copernicus/CMEMS (cmems_drifter)
  • Argo floats data from Copernicus/CMEMS (cmems_argo)
  • moored buoy data from Copernicus/CMEMS (cmems_moored)
  • ISAR measurements from SOC (cmems_isar)

The colocation criteria used are:

  • 5km distance
  • 2 hours window, except for Argo floats (which provide deeper measurements and then it was assumed the time window could be relaxed to increase the number of matchups, given the 10 days sampling of Argo floats)

The datasets assembled so far in the match-ups include:

  • Sentinel-3A WCT level 2 (reference)
  • Sentinel-3A RBT level 1
  • Sentinel-3A WST level 2
  • Metop-A L2P from O&SI SAF (until 23rd Nov. 2016)
  • Metop-B L2P from O&SI SAF
  • Seviri L2P from O&SI SAF
  • MODIS on Aqua L2P from PO.DAAC

Format and access

The match-ups are assembled into daily netCDF files (6-hourly for drifters). They can be collected from Ifremer FTP. Login and password need to be requested to jfpiolle@ifremer.fr.

The data files are organised into a classic //year/day in the year// folder structure. The file nomenclature is S3A_SL_2_WCT_<source>_<start time>_<stop time>.nc where:

  • source is the in situ source (ex: cmems_drifter)
  • start time and stop time are the start and end of the time frame over which match-ups have been collected and assembled

example:

S3A_SL_2_WCT_cmems_drifter_20161025120000_20161025180000.nc