onglet

Articles

• The historical French heritage
  14 December 2010, by Frank

  France is very rich in systematic observations of coastal sea level over long time periods. The oldest (published) series of measurements were performed by the astronomers La Hire and Picard at Brest, France, in 1679, over about ten days. They repeated the experiment in 1692, over several months, again in Brest. Their aim was to study the tides and their results showed the fundamental importance of observation to understand and determine the characteristics of tides in a given place for the (…)

• Le patrimoine historique
  28 mars 2008, par Guy Woppelmann

  La France est très riche en observations systématiques de hauteur d’eau le long des côtes sur de longues périodes de temps. Les plus anciennes séries de mesures (publiées) furent réalisées par les astronomes La Hire et Picard à Brest, en France, en 1679 pendant une dizaine de jours. Ils renouvelleront leur expérience en 1692, pendant plusieurs mois, toujours à Brest. Leur objectif : l’étude de la marée. Leurs résultats montreront l’intérêt fondamental de l’observation pour connaître et (…)

• About
  8 October, by Médéric Gravelle

  The GNSS solution named ’NGL20’ is produced by the Nevada Geodetic Laboratory (NGL) using a Precise Point Positioning (PPP) data analysis strategy. The latest version of GipsyX software and models, orbits and clocks from the Jet Propulsion Laboratory (JPL) have been used to produce daily position time series expressed in the ITRF2020 reference frame (Blewitt et al. 2018). The data set covers the period January 1996 to September 2025.
  The Sixteenth session of the Group of Experts for the (…)

• About
  16 September 2014, by Médéric Gravelle

  The basic concept of plate tectonics is that, to a first approximation, the Earth surface is divided into several rigid plates that move with respect to one another but do not deform internally. The motion of each plate can be described by its Eulerian pole (coordinates and angular velocity). In order to better visualize the internal deformation of a single plate and to visualize the relative movements between plates, we propose a tool to select a reference plate, whose motion can be (…)

• About
  6 February 2014, by eprout01

  This is not really a direct product from SONEL data, but the French tide gauges and their associated data distributed by SONEL helped validating the model, and SONEL supports the distribution of its results.
  Two wave numerical hindcast were realized for the North Atlantic Ocean based on the code WaveWatchIII (hereafter WWIII, Tolman, 2009). The former employs a 1°*1° spatial resolution and is forced by wind fields originating from the 20CR reanalysis (Compo et al., 2011) over the (…)

• About
  14 October, by Médéric Gravelle

  The ULR20 GNSS solution is the result of the reanalysis of 26 years of GNSS data from 2000 to 2025 that has been undertaken within the framework of the SPOTGINS collaborative project. Its associated vertical velocity field is expressed in IGS2020 reference frame.
  The daily PPP position time series have been produced using the GINS software (CNES) and precise GPS & Galileo orbit/clock products of the CNES-CLS IGS Analysis Center.
  Position time series expressed in IGS2020 were then (…)

• About
  22 February 2017, by Mikaël Guichard

  In briefest terms, the approach consists in differencing the sea level time series from a tide gauge with an equivalent time series from satellite altimetry. To the extent that both instruments measure identical ocean signals, their difference is a proxy for the vertical position of the tide gauge. Assuming that the instrumental drifts are negligible, the time series of the sea level differences will then be dominated by vertical land motion at the tide gauge. This is illustrated in the (…)

• Data access
  14 February 2008, by Guy Woppelmann

  The GPS observations are published on the anonymous FTP server of SONEL (ftp.sonel.org). The conditions of access are that the origin of the data is acknowledged in all communications, oral or written. Further details.
  The FileZilla tool is a free client ftp which allows you to access the data.

• A-propos
  12 septembre 2013, par Mikaël Guichard

  – Tendances relatives du niveau marin : Les tendances relatives du niveau marin sont calculées par le PSMSL à partir des marégraphes de la catégorie RLR présentant des séries temporelles d’au moins 30 ans avec 70% de données valides. Seuls sont présentés les résultats des marégraphes pour lesquels une vitesse GPS robuste est disponible. (Plus de détails sur les tendances relatives du niveau marin du PSMSL). Tendances absolues du niveau marin : Les tendances absolues (géocentriques) du niveau (…)

• A propos
  27 janvier 2020, par Médéric Gravelle

  La solution GNSS ’NGL14’ a été développée par le Nevada Geodetic Laboratory (NGL) en utilisant une stratégie de calcul PPP (Precise Point Positioning). Le logiciel de du Jet Propulsion Laboratory (JPL), GipsyX (version 1.0), a été utilisé pour produire des séries temporelles de positions journalières pour plus de 17,000 stations distribuées globalement grâce aux produits d’orbites et d’horloges du JPL exprimées dans le repère de référence IGS14 (Blewitt et al. 2018). La solution couvre la (…)