MOZAMBIQUE CHANNEL

Long-Term Ocean Climate Observations (LOCO)

MOZAMBIQUE CHANNEL

A pilot-project with an array of current meter moorings in 2000-2001 showed that the meridional mass transport through the Mozambique Channel fluctuates remarkably regular with values between 20 Sv northwards and 60 Sv southwards. The mean value for this one year of observations is some 15 Sv southwards (Fig. 1).

Fig. 1 - Volume transport through the Mozambique Channel

The spatial structure of the current field suggested that during the periods with a strong southward flow a current jet seperates from the African coast and forms a large anti-cyclonic eddy. These eddies migrate southward, interact with the Agulhas current and seem to initialize the meandering of the Agulhas current, thereby influence the formation of Agulhas rings. Thus the flow in Mozambique Channel is of importance not only for the tropical-subtropical transport in the Indian Ocean but also for the Indian-Atlantic ocean exchange.

At intermediate and deep levels against the African continental slope a northward flowing Mozambique Undercurrent was observed with a mean northward speed of 4.6 cms-1 (1500 m) and 4.5 cms-1 (2500 m). Hydrographic observations showed that the deepest flow consists of North Atlantic Deep Water.

As part of the LOCO program a new array of moorings, with much more current meters, ADCP�s and T-S sensors, was deployed at the narrowest section in the Mozambique Channel in November 2003 (Fig. 2 and 3). These sub-surface moorings will be serviced each 1.5 years and the observations will continue till 2008. The observations will be used mainly to quantify the variability of the meridional mass and heat transport, to relate this variability to Indian Ocean (or El Nino) climate modes and to study the relation between this variability and the �downstream� formation of Agulhas Rings.

Fig. 2 - Mooring section Mozambique Channel

Fig. 3 � LOCO Moorings Mozambique Channel

List of Research Cruises:

� Mozambique Channel [ M75/1b ]

- RV Meteor (January/February 2008)

� Mozambique Channel [ D301/302 ]

�- RRS Discovery (March/April 2006)

� Mozambique Channel [ D289B ]

- RRS Discovery (February/March 2005)

� Mozambique Channel [ CD153B ]

- RRS Charles Darwin (November 2003)