Full‐Depth Eddy Kinetic Energy in the Global Ocean Estimated From Altimeter and Argo Observations
Qinbiao Ni, Xiaoming Zhai, J. H. LaCasce, Dake Chen, David P. Marshall
Abstract
Abstract Although the surface eddy kinetic energy (EKE) has been well studied using satellite altimeter and surface drifter observations, our knowledge of EKE in the ocean interior is much more limited due to the sparsity of subsurface current measurements. Here we develop a new approach for estimating EKE over the full depth of the global ocean by combining 20 years of satellite altimeter and Argo float data to infer the vertical profile of eddies. The inferred eddy profiles are surface‐intensified at low latitudes and deep‐reaching at mid‐ and high latitudes. They compare favorably to the first empirical orthogonal function obtained from current meter velocities. The global‐integrated EKE estimated from the inferred profiles is about 3.1 × 10 18 J, which is close to that estimated from the surface mode (3.0 × 10 18 J) but about 30% smaller than that estimated from the traditional flat bottom modes (4.6 × 10 18 J).