Navidad current and North Atlantic Oscillation

Lively Data: February 24, 2010

Merged maps of Sea Level Anomalies (in cm) for the North East Atlantic Ocean, averaged on November-December 2009 (top) and 1999 (bottom). For the 2009 map, choose the NRT - Global - (Maps of) Sea Level Anomalies. The 1999 map is done with the Delayed-Time data (choose DT - Global - (Maps of) Sea Level Anomalies). To average the data on a given period, in Define variable, click on "T" and search the 2 choosen months. Click on Next to limit the area and define a common map scale in order to compare the 2 years.

Winter warming is observed off northern Spain with a warm and salty surface current nammed Navidad. It circulates poleward and develops numerous eddies which interact with the bottom topography along the continental slope. These typical eddies are nammed swoddies (Slope Water Oceanic Eddy). Some of them can persist until the next Summer for marked Navidad years.

The interannual variability of the Navidad current is correlated the North Atlantic Oscillation (NAO) Index. A marked Navidad is observed with low values of the NAO.

The LAS can easily be used to map these swoddies. In winter 2009-2010, with a negative NAO, these Navidad linked-structures appear numerous: not less than 6 eddies are counted on Maps of Sea Level Anomalies averaged between November-December 2009 (top). On the contrary, when the NAO index is significantly positive, as in Winter 1999, no Navidad structure are observed (bottom).

 

Further information:

Use the Live Access Server