Mobile version

Seasonal reverse in the Somali current

Lively Data: January 26, 2010

Along the Somali coast, the seasonal circulation changes drastically with a spectacular reverse in the Somali current. In this part of ocean, winds and currents (atmosphere and ocean) are strongly coupled. The circulation variations are due to changes in the wind stress associated with the Indian monsoon.

During winter, winds flow southwestward in the northwestern Indian Ocean. During this Northeast monsoon (also called the Winter monsoon), the winds drive a southwestward boundary current along the coast of Somali.

 

Top: Merged maps of Sea Level Anomalies (in cm) averaged on February 2008 in the northeast part of Indian Ocean. To made a such map with the LAS, choose DT - Global - (Maps of) Sea Level Anomalies Merged. In Define variable, choose Average, "T" then the reference period (2008/01/30 - 2008/03/03) . Click on Next then select the area 38°E/64°E/6°S/18°N.

Below:  Maps of Geostrophic Velocity Anomalies cm/s the February 06, 2008, off the Somali coast. . Choose DT - Global - (Maps of) Geostrophic Velocity Anomalies , Variable(s): Vector (U,V), the date, and the geographical area.

During the Southwest monsoon in summer, winds flow northeastward and drive a northward flow all along the Somali coast. As a consequence of the Coriolis force, Ekman transport shifts these upper warm waters offshore permitting upwelling of cooler waters along the coast. The difference from the previous map is immediately obvious.

The configuration of the Somali current during this Southwest monsoon comes close those of western boundary currents. On this account, the Somali Current is the analogue to the Gulf Stream in the Atlantic, and Kuroshio in the Pacific. But, unlike them, the western boundary current for the northern Indian Ocean is only present part of the year.

Top: Merged maps of Sea Level Anomalies (in cm) averaged on August 2008 in the northeast part of Indian Ocean. To made a such map with the LAS, choose DT - Global - (Maps of) Sea Level Anomalies Merged. In Define variable, choose Average, "T" then the reference period (2008/07/30 - 2008/08/27) . Click on Next then select the area 38°E/64°E/6°S/18°N.

Below:  Maps of Geostrophic Velocity Anomalies cm/s the August 06, 2008, off the Somali coast. . Choose DT - Global - (Maps of) Geostrophic Velocity Anomalies , Variable(s): Vector (U,V), the date, and the geographical area.

Further information:

  • Lively Data:
    • May 23, 2005 : <link en data data-access-services live-access-server-las lively-data may-23-2005-looks-on-indian-monsoon index.html _self internal-link>Looks on indian monsoon.
    • August 28, 2006: A breath of air in Arabian Sea
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!