CERSAT

First CCI Sea State+ Dataset Release v1.1

The European Space Agency (ESA) and the CERSAT / Laboratory of Ocean Physics and remote Sensing (LOPS) are pleased to announce the release of the Sea State Climate Change Initiative altimeter data set Version 1.0. The Sea State CCI project is currently reanalyzing the full Earth Observation archive of altimeter and SAR data in order to produce the most complete, accurate and robust global data set on sea state parameters. To achieve this goal, dedicated waveform retracking, data editing and data processing methods are being developed. Moreover, systematic cross-calibration and validation against in-situ and remote sensing data set are being conducted.

This pre-release builds on the former GlobWave data set (http://globwave.ifremer.fr/) and extends its coverage up to 2018, including the most recent Saral, Jason-3, Cryosat-2 missions. The data thus encompasses 28 years of data from 1991 (ERS-1) to 2018. In addition, an adaptive wavelet-type denoising algorithm based on Empirical Mode Decomposition and wavelet thresholding (see Huang et al, Kopsinis and MacLaughlin., Quilfen et al., 2019) has been applied to the along-track significant wave height parameter. The denoised swh parameter hence reveals submeso-scale patterns that are ordinary hidden within the background noise (Quilfen et al., 2018, 2019). Finally, auxiliary parameters (observed or simulated)) relevant to the study of sea state variability (ice mask, winds, sea level...) have been added to the data set to facilitate cross-parameter studies.

The architecture of the data set follows the ESA CCI format so that users can benefit from the powerful CCI visualizing an processing tools currently developed at ESA. This data can be found on Ifremer ftp server by registering here or directly on ESA CCI Portal.

To sum up, the Altimeter Sea State CCI data set V1.0 includes:

  • a 28-year (1991-2018) data set of cross-calibrated altimeter-derived parameters (significant wave height, sigma0, mean square slope);
  • 10 processed missions (envisat, ers-1, ers-2, gfo, jason-1, jason-2, jason-3, cryosat-2, saral, topex);
  • two new geophysical parameters: the along-track denoised significant wave height and the corresponding noise;
  • an extensive set of auxiliary (observed and simulated) parameters: sea ice concentration from CCI SeaIce, sea surface height from CCI SeaLevel, bathymetry, distance to coast, surface parameters from ERA5 reanalysis (air temperature, sea surface temperature, wind, pressure, atmospheric liquid water content)

References:

Dodet, G., Piolle, J.-F., Quilfen, Y., Abdalla, S., Accensi, M., Ardhuin, F., Ash, E., Bidlot, J.-R., Gommenginger, C., Marechal, G., Passaro, M., Quartly, G., Stopa, J., Timmermans, B., Young, I., Cipollini, P., Donlon, C., 2020. The Sea State CCI dataset v1: towards a sea state climate data record based on satellite observations. Earth System Science Data 12, 1929–1951. https://doi.org/10.5194/essd-12-1929-2020

Product User Guide (PUG) v1.0, 17 January 2020. This document is a guide to version 1.1 CCI sea state products that update and extend products from the GlobWave project.