Mobile version

Cold winter and negative North Atlantic Oscillation index

Lively Data: December 17, 2010

As the winter of 2009-2010, the beginning of this 2010-2011 winter is unusually cold over Europe. As the winter NAO index was largely negative in 2009-2010, this index is already negative during the last months of 2010. Does it suggest the same colder winter for the next months ?

The NAO index measures the difference of atmospheric pressure between the Azores anticyclone and the low-pressure system over Iceland. Its fluctuations have a direct impact on the climate of Europe, particularly in Western Europe. During a negative phase (Azores high, Iceland low, like in 2009-2010 and end 2010),  westerlies winds over North Atlantic ocean are weaker, bringing less moisture in the air to northern Europe, and less heat. This situation allows cold air into Northern Europe from the cold Siberian anticyclone.

By comparing the ocean situation in 2009-2010 and the situation today, some sights are similar.

The time serie of  the SWH averaged over a northern area (22°W/18°W/55°N/59°N) highlights high SWH during the end of 2009 (almost 7.5 m early in December 2009) and the end of 2010 (almost 6.5 m early in November 2010).

Numerous swoddies are observed off Northern Spain. These structures are correlated with low values of the NAO (see our Lively Data in February 24, 2010: Navidad current and North Atlantic Oscillation).

EnglishFrançais
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!