Global mean comparisons between altimetry and tide gauges: focus over the TOPEX-A period

Pierre Prandi (CLS, France)


Guillaume Valladeau (CLS, FRANCE); Lionel Zawadzki (CLS, France); Michael Ablain (CLS, France); Vincent Debout (CLS, France); Jean-Damien Desjonquères (CNES, France )

Event: 2016 Ocean Surface Topography Science Team Meeting

Session: Science I: Current and past mean sea level observations

Presentation type: Type Poster

Global comparisons between altimetry and tide gauges performed by different groups over the last two years suggest that TOPEX side A is overestimating the global mean sea level trend. This year a team at CLS has explored the possibility to use Poseidon data to correct a drift on TOPEX-A (rather than fitting Poseidon data to TOPEX-A). The description of the method used and its limitations are presented as separate abstract by Zawadzki et al. Whether a Poseidon-calibrated record for the first part of the altimetry time series is more accurate than the current one remains to be demonstrated, and comparisons to tide gauges can be helpful.

In this study we compare global mean bias estimates between altimetry and tide gauges data for the original TOPEX-A and Poseidon-calibrated records. Unexpected results of a preliminary analysis led to turning this experiment into a good opportunity to investigate biases, sensitivities and uncertainties of our global comparison method. Effects of data gaps in time series, of the referencing method, and of the length/number of stations ratio are investigated with a focus on the TOPEX-A period.


Poster show times:

RoomStart DateEnd Date
Grande Halle Thu, Nov 03 2016,11:00 Thu, Nov 03 2016,18:00
Pierre Prandi