Mobile version

Adding an in-depth view to altimetry

Image of the month - September 2002

Drifting buoys tracked by Argos (black lines) over sea level anomalies from altimetric satellites Topex/Poseidon and ERS-2 (Ssalto/Duacs data). The animation (5 Mo) shows that buoys drift with the ocean currents, which circulate in a counter-clockwise direction around the hills and in a clockwise (anticyclonic) direction around the valleys (in the Southern Hemisphere). Their general direction is dictated by the Antartic Circumpolar Current.
(Credits Météo France/CLS).

The one major drawback of observing the oceans from space is that electromagnetic waves emitted and received by the satellite do not penetrate far beneath the sea surface. Altimetry satellites able us to estimate many phenomena over the whole water column, however, it can't replace in-situ measurements. Such sensors allow us to generate a three-dimensional picture of the ocean. But in-situ sensors provide point measurements, at a particular moment in time and space, and need people to be released, sometimes refitted,... Satellite-based systems such as Argos, however, make it possible to automatically retrieve data in near-real time. Satellites covers the whole Earth (or most of it), continuously.
In-situ measurements also validate and calibrate satellite instruments. Large-scale international programmes such as Argo are now taking shape to provide the widest possible coverage of the oceans by in-situ instruments. to complement spaceborne programmes. Complementarity of satellite and in-situ data is one of the keys for a three-dimension modeling of the ocean, and for its forecasting.

See also:

Websites on this subject:

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!