Image of the month Cold and warm eddies pair off Vietnam
Image of the Month - September 2011
Sea level anomalies just East of Vietnam on June 1st, July 15, September 2, 2011. In June, the pair of eddies (one cold -- below average sea surface height -- North, at about 12°N, 111°E, one warm eddy, just below) is barely visible. Both eddies strengthen throughout the Summer, their feature more or less obvious depending on the date. (Credits CLS/Cnes).
The oceanic circulation in the South China Sea depends quite strongly on the monsoon. In Summer, in particular, eddies are born from the interaction of the monsoon winds with the reliefs of the coasts (East Vietnam). Every two to four years, an eddy pair (an anti-cyclonic southern eddy and a cyclonic northern eddy) appears at about 111°E, 13°N in June/July and stays till October, with a variability related to local winds. These two eddies interact with the thermocline structure and thus the local physical conditions in the ocean.
Studying such features with altimetry, now over nearly twenty years, enable to see the variability and changes. With the next altimetry missions, even longer time series will be available, thus showing long-term changes.
See also:
- Data: <link en data product-information duacs index.html _self internal-link>Ssalto/Duacs near-real and delayed time multimission altimeter products
- Applications: mesoscale ocean circulation
- Image of the Month, March 2010: Eddies in the Gulf of Alaska
