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 (…)

• Calibration measurements
  10 December 2010, by Frank

  These are measurements of the water level which are carried out simultaneously with a tide gauge and an instrument that is used as a standard, often an electric sound/light sensor. When the measurements are performed over a complete tide cycle (12h25), they can be used to produce a Van de Casteele diagram. The shape of this diagram is highly instructive; it can be used to assess the performances of the tide gauge and to detect any operational defects. This type of test is recommended by (…)

• Role of SONEL
  27 October 2011, by Guy Woppelmann

  In addition to its national scope with its specific aims associated with a national research observation infrastructure on sea level, SONEL plays the role of GNSS at tide gauge data assembly centre for the GLOSS programme since 2011 (see GLOSS Implementation Plan - 2012, pp. 23). SONEL is also the primary data centre for the GPS Tide Gauge Benchmark Monitoring (TIGA) pilot project, which has turned into a working group of the International GNSS Service (IGS) in 2010.
  Consequently, SONEL (…)

• 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 (…)

• À-propos
  3 novembre 2020, par Guy Woppelmann

  La solution GPS ULR6b est une version actualisée de ULR6a, alignée dans le repère de référence terrestre ITRF2014, alors que ULR6a est dans l’ITRF2008. Les deux solutions ULR6 résultent de la réanalyse de 19 ans de données GPS allant de 1995 à 2014, réalisées dans le cadre de la seconde campagne de réanalyse de l’International GNSS Service (IGS, plus d’infos ici).
  Les observations de phase de l’onde porteuse GPS ont été analysées en double-différence, sans ionosphère, sur un réseau de 756 (…)

• À-propos
  14 novembre 2022, par Médéric Gravelle

  La solution GPS ULR7a est une version préliminaire issue de la réanalyse de 21 ans de données GPS allant de 2000 à 2020, qui a pris part à la 3ème campagne de réanalyse de l’International GNSS Service (IGS, plus d’infos ici). Le champ de vitesse associé est exprimé dans le repère ITRF2014.
  Les observations de phase de l’onde porteuse GPS ont été analysées en double-différence, sans ionosphère, sur des sous-réseaux régionaux (plus un global) journaliers de 546 stations, en utilisant la (…)

• 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 (…)

• Statistiques
  14 novembre 2022, par Médéric Gravelle

  Champs de vitesse vertical Vitesses (robustes) estimées : 546 CGPS@TG 461 Moyenne des erreurs formelles : 0.38 mm/an Médiane des erreurs formelles : 0.28 mm/an

• French contribution
  22 August 2017, by Frank

  Observation stations contributing to GLOSS
  The map on the right shows the French stations contributing to the GLOSS core network of stations, a contribution which was agreed by France when the programme was started at the beginning of the 1980s. Despite its heritage and the wealth of sea level data, the French contribution to the world programme appears relatively modest. There are numerous organisations which use the tide gauges in France as part of their missions. Nevertheless the (…)

• 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 (…)