Mean rise in sea level is only part of the story

The rise in the level of the oceans is far from uniform. In fact, while in certain ocean regions the sea level has indeed risen (by up to 20 millimetres a year in places), in others it has fallen an equivalent amount. These regional differences, observed by Topex/Poseidon since 1993, mostly reflect sea level fluctuations over several years., estimates of the rise in sea level-now running at 2.5 millimetres a year-have gained in accuracy.

Combined map of regional patterns of observed sea level (in mm/year). This map can be obtained using gridded, multi-mission Ssalto/Duacs data since 1993, which enable the local slopes to be estimated with a very high resolution (1/3 of a degree on a Mercator projection). Isolated variations in MSL are thus revealed, mainly in the major ocean currents. (Credits CLS/Cnes/Legos).
Download the data (NetCDF).

 

 

 

 

 

El Niño is behind rise in sea level

Global Mean Sea Level (MSL, blue line) and Sea Surface Temperature (SST, red dotted line) from early 1993 to mid-1998. In 1997 there was a rise of 15 mm. (Credits CNRS/Legos).

The meteorological effects of El Niño 1997-1998 were felt worldwide, but it also contributed to variations in mean sea level. Indeed, sea level anomalies measured by Topex/Poseidon were over 20 centimeters in the equatorial Pacific when the phenomenon was at its height (and as much as 30 centimeters off the coast of Peru). These anomalies obviously had an effect on the global mean of sea levels.

 

 

 

 

Mediterranean Sea

Mean sea level evolution in Mediterranean Sea

Sea level trend (mm/year) in the Mediterranean for October 1992 to December 2010 (Credits Cnes/Legos/CLS).

The sea level in the Eastern Mediterranean basin has risen significantly in recent years, apparently due to warmer water temperatures (observed by in-situ measurements). But if we look at the Ionian Sea off the tip of Italy, data acquired by Topex/Poseidon show that sea level in fact fell.

EnglishFrançaisEspañol
Rss feedsContactSitemapPartnersFAQGlossaryLexicon
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

The new 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!