Mobile version

Thule Doris station's rising at different velocities

Image of the Month - February 2016


The Earth is constantly changing shape. To be understood, when the motion of the Earth's crust is observed, it must be referenced. A Terrestrial Reference frame provides a set of coordinates of some points located on the Earth's surface. It can be used to measure plate tectonics, regional subsidence or loading and/or used to represent the Earth when measuring its rotation in space. Nowadays, four main geodetic techniques are used to compute accurate coordinates: the GPS, VLBI, SLR, and Doris. The International Terrestrial Reference Frames (ITRF) coordinates are obtained by combination of individual solutions computed by analysis centers using the observations of the four Space Geodesy techniques. They all use networks of stations located on sites covering the whole Earth. The ITRF is constantly being updated (the latest is the ITRF2014). All its releases include station positions and velocities. They model secular Earth’s crust changes.

For the Doris contribution to the International Terrestrial Reference Frame 2014, the Combination Center of the International Doris Service (IDS) estimated a new version of the coordinates time series of all the Doris station over the 1993-2015 time span. That new set of coordinates is the result of the combination of the individual solutions from the six IDS Analysis Centers.
As preliminary step of the estimation of very precise mean positions and mean velocities, the Doris station coordinates time series were investigated, looking for significant discontinuities and change of velocities. The Thule station is especially interesting, with Greenland glacier melt a major concern. We already had a look at it in these pages (Image of the Month, June 2013), and noticed its general dynamics. However, it seems that the mean trend is not the whole story, and several phases can be seen if measurements are closely studied. Vertical velocities at coastal sites are critical as they may impact the study of local sea level variations through the analysis of the co-localized tide gauge records (e.g. a local level as measured by a tide gauge might be decreasing because the land is rising). Doris station data analysis, and the contribution to ITRF enable to closely monitor such variations and try and understand them.

See also:

 Websites on this subject:


  • Moreaux, G., Lemoine, F.G., Capdeville, H., et al., 2016. The International DORIS Service contribution to the 2014 realization of the International Terrestrial Reference Frame. Advances in Space Research, In press, doi: 10.1016/j.asr.2015.12.021.
Rss feedsContactPartnersFAQLexiconLegal noticePersonal Data Protection PolicyMobile
You must enable cookies in your browser preferences to save the modifications
You are using an older version of Internet Explorer, please update to take full advantage of Aviso+ features

Customize the home page

View all widgets
Reduce display
Public profile
User profile

Select/Deselect widgets

Discover AVISO+

Customizable home, reading tools, products search guide, etc.. Discover step by step the features of the new site AVISO+.

Customizable homepage

This home page is composed of blocks called "widgets".

Rearrange the blocks with a "Click & Drop".

Hide a widget with the cross at the top right. Reset or add a widget with the "wrench" icon. The "User" and "Public" profiles offer a predefined organization.

All the modifications are automatically saved as cookies on your machine so as to enable you to have your own specific AVISO+.

Reading tools

Ease your reading by choosing the page background colour (black/white) and/or by modifying the font size.

Browsing menu and breadcrum trail

To ease your browsing through AVISO+, you can use at any time the main banner items with the interactive submenus or use the browsing menu on the left side of the screen (it is open by default). For more readiness of the page contents, you can fold and unfold the browsing menu by clicking on the tab. At any time you can know where you are thanks to the browsing menu or the breadcrum at the top of the page.

Products search guide

The first submenu of the "Data" banner item leads you to a new search form enabling you to find quickier the product that suits your needs. The list of results is updated according to your selection criteria.

AVISO+ Multimedia

The first submenu of the "Multimedia" banner item leads you to AVISO+ collections of images and videos linked to altimetry and its applications. Have a nice visit!