-
Project
Description
Region of Study
Time Series
Monitoring both the Agulhas transport into the South Atlantic in the upper kilometer of the ocean and the number of rings shed at its retroflection provides a means of detecting any substantial changes in inter-ocean water exchanges. After calibrating the observations with an array of inverted (IES) echo sounds, satellite altimetry has been used to estimate inter-ocean exchange between the Indian and Atlantic Oceans and has been maintained since 1993.
The transfer of warm water from
the Indian Ocean to the South Atlantic subtropical gyre takes place in
the form of rings and filament formed when the Agulhas Current
retroflects south of Africa between 15°E and 25°E. It has been observed a closed
correlation between the transport of this current and the shedding of
rings (Goni et al, JMR, vol.55, 861-883, 1997). We provide here
the estimated time series of the location of the jet and of the
geostrophic transport of the Agulhas Current using a combination of
Satellite altimetry fields and climatological hydrography.
Location of the Agulhas Current
jet
Weekly gridded sea height anomaly fields from AVISO were added to the
mean dynamic height (ref 1000m) field produced by the OCCAM model to
obtain the dynamic height field. The dynamic height along 20°E was then extracted. The maximum
value of sea height between 35°S
and 40°S is indicative of the
location of the retroflection. The
jet of the current was placed in the location of the maximum slope of
sea height north of the retroflection. The time series presented
here was filetered with a running mean of 5 weeks.
Transport of the Agulhas Current
The fields as above were used to extract the dynamic height along 28°E. The geostrophic transport was
computed between 36°S and the
location of the retroflection along that longitude, which was estimated
using the procedure describe above. The time series presented
here was filtered with a running mean of 5 weeks.
Near-real time monitoring of
these
parameters
We will soon start updating these time series once a month.
Please direct your questions to:
Gustavo Goni
Atlantic Oceanographic & Meteorological Laboratories
4301 Rickenbacker Causeway,
Miami, FL33139, USA
Phone: (305) 361-43392
Fax: (305) 361-4412
