Mobile version

Sorting ice from space

Image of the Month - June 2008

Satellite altimetry is a major tool to better understand ice sheet behaviour. In particular Envisat dual-frequency altimeter and radiometer provide measurements up to 82° of latitude,  and so covers a large part of the Earth's iced surfaces.

The frequencies used by the altimeter and radiometer penetrate differently within the snow (see e.g.  Image of the Month, October 2006: Altimeter looks into the crevasses). Moreover, the measurements taken depend on the snow characteristics. It is thus possible to separate regions of distinct snow morphology.

The different categories of snow thus defined are in good agreement with previous studies based on in situ or scatterometer data. They defined categories (facies) such as dry snow, percolation (when surface ice melt and percolates through the snow, refreezing eventually), wet snow (with free water), and bare ice (i.e. winter snow have melt, leaving the underlying ice exposed). Such partition of Greenland using spaceborn sensors enables finer  monitoring of areas highly sensitive to climate variations.

See also:

  • Applications: Ice


  • Tran, N, F. Rémy, P. Féménias, Snow facies over ice sheet derived from Envisat active and passive observations, IEEE Trans. Geosci. Remote Sens., Vol. 46,  No 11,  3694 - 3708,  November 2008, doi 10.1109/TGRS.2008.2000818.
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!