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 (…)

• Download
  17 January 2020, by Médéric Gravelle

  – Vertical velocities table
  The JPL14_Vertical-Velocities_Table provides the vertical GPS velocities and uncertainties from the 436 stations fulfilling the criteria of 3 years of minimum length and data gaps not exceeding 30%, estimated by the JPL group.
  – Daily time series
  The JPL14.zip file contains individual station data files of daily position time series in ITRF2014 with respect to the position at the epoch 2023-01-01. These positions are expressed in meters in the local frame (…)

• About
  13 September 2013, by Mikaël Guichard

  – Relative sea level trends: The relative sea level trends have been estimated by the PSMSL from the RLR tide gauge dataset of annual times series longer than 30 years with more than 70% of valid data. Only results from tide gauges for which a robust GPS velocity is available are displayed. (More about the PSMSL relative sea level trends). Absolute sea level trends: The absolute (geocentric) sea level trends build upon the above-mentioned relative sea level trends by simply adding the (…)

• Results of the calibration tests
  10 December 2010, by Frank

  The results of the test measurements ’in situ’ are directly incorporated into the pages corresponding to the tide gauge in question. The test missions are generally the subject of a report in which the results of the use of the calibration measurements (Van de Casteele diagram) are published. Here is an example: test of the tide gauge at Socoa (Saint Jean-de-Luz) in May 2007.

• Description of the DORIS tracking beacons
  10 December 2010, by Frank

  The DORIS network of tracking beacons was established by IGN in 1986 and has been run and maintained by them since then. Geodetic files describe the stations of the DORIS network. They are avilable on the web site of IDS (International DORIS Service) on a page that also has a dynamic map showing the geographical distribution of the network (click on the link).

• Description des balises DORIS
  3 avril 2008, par Guy Woppelmann

  Le réseau de balises DORIS est déployé et maintenu par l’IGN depuis 1986. Des fiches géodésiques décrivent les stations DORIS de ce réseau. Elles sont disponibles sur le site de l’IDS (International DORIS Service) à travers une page qui propose également une carte dynamique montrant la distribution géographique du réseau (cliquez sur le lien pour y accéder).

• 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 (…)

• About
  4 March 2020, by Médéric Gravelle

  The ULR6b GPS solution is an updated version of ULR6a. That is, ULR6b is aligned in the ITRF2014 reference frame, instead of ITRF2008 for ULR6a. Both UMR6 solutions result from the reanalysis of 19 years of GPS data from 1995 to 2014, carried out within the framework of the 2nd reanalysis (reprocessing) campaign (repro2) of the International GNSS Service (IGS).
  Double-differenced ionosphere-free GPS carrier phase observations from a global network of 756 stations were reanalyzed using (…)

• How to access the tide gauge observations
  20 February 2011, by Guy Woppelmann

  The files of average values
  Only the daily, monthly and annual averages calculated from quality controlled (QC’ed) data are provided in the data files. However, the graphs show the averages calculated from QC’ed observations (in blue) and non-QC’ed observations (in red). The averages are calculated from the Demerliac filter and the Doodson filter, with the possibility of a choice for the user. An example is given on the image below, which is taken from the web page of the La Rochelle (…)