01 Jun 2022
01 Jun 2022
Status: this preprint is open for discussion.

Current observed global mean sea level rise and acceleration estimated from satellite altimetry and the associated uncertainty

Adrien Guérou1, Benoit Meyssignac2,3, Pierre Prandi1, Michaël Ablain4, Aurélien Ribes5, and François Bignalet-Cazalet3 Adrien Guérou et al.
  • 1Collecte Localisation Satellite (CLS), Ramonville Saint-Agne,31250, France
  • 2LEGOS, CNRS, IRD, Université Paul Sabatier, Toulouse, 31400, France
  • 3Centre National d’Etudes Spatiales (CNES), 31400 Toulouse, France
  • 4MAGELLIUM, Ramonville Saint-Agne, 31520, France
  • 5CNRM, Université Paul Sabatier, Météo France, CNRS, Toulouse, 31400, France

Abstract. We present the latest released of the Global Mean Sea Level (GMSL) record produced by the French space agency CNES and distributed on the AVISO+ website. This dataset is based on reprocessed along-track data, so-called L2P 21, of the reference missions Topex-Poseïdon, Jason-1/-2 and -3. The L2P 21 CNES/AVISO GMSL record covers the period January-1993 to December-2021 and is now delivered with an estimate of its uncertainties following the method presented in Ablain et al. (2019). Based on the latest Calibration and Validation (Cal/Val) knowledge, we updated the uncertainty budget of the reference altimetry missions and demonstrate that the CNES/AVISO GMSL record now achieves stability performances of ±0.3 mm/yr at the 90 % confidence level (C. L. ) for its trend and ±0.05 mm/yr2 (90 %C. L. ) for its acceleration over the 29-years of the altimetry record. Thanks to an analysis of the relative contribution of each uncertainty budget contributor, i.e. , the altimeter, the radiometer, the orbit determination, the geophysical corrections, we identified the current limiting factors to the GMSL monitoring stability and accuracy. We find that the radiometer Wet Troposphere Correction (WTC) and the high-frequency errors with timescales shorter than 1-year are the major contributors to the GMSL uncertainty over periods of 10-years (30–70 %), both for the trend and acceleration estimations. For longer periods of 20-years, the TP data quality is still a limitation but more interestingly, the International Terrestrial Reference Frame (ITRF) realisation uncertainties becomes dominant over all the others sources of uncertainty. Such a finding challenges the altimetry observing system as it is designed today and highlights clear topics of research to be explored in the future to help the altimetry community to improve the GMSL accuracy and stability.

Adrien Guérou et al.

Status: open (until 08 Aug 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-330', Thomas Frederikse, 22 Jun 2022 reply
    • AC1: 'Reply on RC1', Adrien Guerou, 01 Jul 2022 reply

Adrien Guérou et al.

Adrien Guérou et al.


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Short summary
Based on the latest satellite observations published by the French CNES space agency, we present the current state of the sea level at the scale of the planet and assess its rise and acceleration over the past 29 years. To support stakeholders decisions we provide updated quantified estimations of our confidence on our estimations and highlight key technological and scientific fields to make progress on that will help to better characterise the sea level evolution in the future.