[AOS18-P03] An irregularly shaped warm eddy observed by Chinese underwater gliders
Keywords:Irregular shape, Warm eddy, Chinese underwater glider
Mesoscale eddies are important for transporting oceanic energy and matter. We investigated the three-dimensional structure
of an irregularly shaped warm eddy using three Chinese underwater gliders and satellite data during May 2015 in the northern
South China Sea. The warm eddy lasted for 2 months, remained quasi-steady, and had a mean radius of ~ 70 km from May
10 to May 31. The heat contents observed along the two glider tracks differed markedly, by 2 × 109 J/m2, which reflected an
imbalance in the geostrophic and tangential velocity distributions of the eddy. The geostrophic/tangential velocity decreased/
increased with depth within the warm eddy. The maximum tangential velocities calculated using the datasets from the two
gliders were 0.8 and 0.25 m/s, respectively, confirming that the shape of the warm eddy was horizontally asymmetrical.
Large errors can arise when the heat, energy, and matter transport for an irregularly shaped eddy are estimated using a regular
circular model. We suggest that more intersecting glider tracks should be used to retrieve the three-dimensional eddy structure,
and that those tracks should be better designed. The irregular shape of the warm eddy was likely induced by oceanic
currents such as the wind-induced Ekman current. Further study is needed to elucidate the eddy–current interactions and
the mechanisms thereof.
of an irregularly shaped warm eddy using three Chinese underwater gliders and satellite data during May 2015 in the northern
South China Sea. The warm eddy lasted for 2 months, remained quasi-steady, and had a mean radius of ~ 70 km from May
10 to May 31. The heat contents observed along the two glider tracks differed markedly, by 2 × 109 J/m2, which reflected an
imbalance in the geostrophic and tangential velocity distributions of the eddy. The geostrophic/tangential velocity decreased/
increased with depth within the warm eddy. The maximum tangential velocities calculated using the datasets from the two
gliders were 0.8 and 0.25 m/s, respectively, confirming that the shape of the warm eddy was horizontally asymmetrical.
Large errors can arise when the heat, energy, and matter transport for an irregularly shaped eddy are estimated using a regular
circular model. We suggest that more intersecting glider tracks should be used to retrieve the three-dimensional eddy structure,
and that those tracks should be better designed. The irregular shape of the warm eddy was likely induced by oceanic
currents such as the wind-induced Ekman current. Further study is needed to elucidate the eddy–current interactions and
the mechanisms thereof.