Journal Article

Deep Learning Improves Global Satellite Observations of Ocean Eddy Dynamics

Martin, Scott A., Klein, Patrice, Manucharyan, Georgy E.

2024

Overview

Ocean eddies affect large‐scale circulation and induce a kinetic energy cascade through their non‐linear interactions. However, since global observations of eddy dynamics come from satellite altimetry maps that smooth eddies and distort their geometry, the strength of this cascade is underestimated. Here, we use deep learning to improve observational estimates of global surface geostrophic currents and explore the implications for the cascade. By synthesizing multi‐modal satellite observations of sea surface height (SSH) and temperature, we achieve up to a 30% improvement in spatial resolution over the community‐standard SSH product. This reveals numerous strongly interacting eddies that were previously obscured by smoothing. In many regions, these newly resolved eddies lead to nearly an order‐of‐magnitude increase in the upscale kinetic energy cascade that peaks in spring and is strong enough to drive the seasonality of large mesoscale eddies. Our study suggests that deep learning can be a powerful paradigm for satellite oceanography. Plain Language Summary We developed a deep learning method to estimate global maps of surface ocean currents from satellite observations with significantly improved resolution and accuracy compared to existing methods. These maps dramatically improve our ability to observe eddy dynamics and the impact of eddies on the transfer of energy between scales in the ocean. Our study suggests that deep learning can be a powerful paradigm for satellite oceanography. Key Points We develop the first deep learning global estimates of surface ocean currents from multi‐modal satellite observations Our deep learning method is able to map surface currents with state‐of‐the‐art resolution and accuracy The diagnosed kinetic energy cascade is an order of magnitude higher compared to conventional altimetry products

• Publisher: John Wiley & Sons, Inc,American Geophysical Union,Wiley
• Subject: Altimetry / Deep learning / Eddies / Eddy currents / energy cascade / Kinetic energy / Mesoscale eddies / Observational learning / Ocean circulation / Ocean currents / ocean eddies / Oceanic eddies / Oceanography / Oceans / Satellite altimetry / Satellite observation / Satellites / Sciences of the Universe / Sea currents / Sea surface / Seasonal variations / Seasonality / Spatial discrimination / Spatial resolution / surface currents / Transfer learning