Airborne observations of fast-evolving ocean submesoscale turbulence

• Published in: Communications earth & environment 2024-12, Vol.5 (1), p.771-10
• Main Authors: Torres, Hector S., Rodriguez, Ernesto, Wineteer, Alexander, Klein, Patrice, Thompson, Andrew F., Callies, Jörn, D’Asaro, Eric, Perkovic-Martin, Dragana, Farrar, J. Thomas, Polverari, Federica, Akbar, Ruzbeh
• Format: Article
• Language: English
• Subjects: 639/33/445/242; 704/106/829/2737; 704/829/2737; Airborne observation; Apollo spacecraft; Atmospheric turbulence; Carbon; Climate system; Doppler effect; Earth; Earth and Environmental Science; Earth Sciences; Eddies; Environment; Evolution; Image processing; Infrared imagery; Infrared radar; Nutrients; Ocean circulation; Ocean color; Oceanic turbulence; Oceans; Radar imaging; Satellite imagery; Scatterometers; Spacecraft; Spatial discrimination; Spatial resolution; Strong interactions (field theory); Surface velocity; Synthetic aperture radar; Turbulence; Upper ocean; Velocity; Velocity distribution
• ISSN: 2662-4435
• DOI: 10.1038/s43247-024-01917-3

Ocean images collected by astronauts onboard the Apollo spacecraft more than 50 years ago revealed a large number of ocean eddies, with a size between 1 and 20 km. Since then, satellite infrared, ocean color, sun glitter and synthetic aperture radar images, with high spatial resolution, have confirmed the ubiquitous presence of these small eddies in all oceans. However, observing the dynamical characteristics and evolution of these eddies has remained challenging. An experiment was recently carried out in the California Current system using the new airborne Doppler Scatterometer (National Aeronautics and Space Administration-Jet Propulsion Laboratory DopplerScatt) instrument that observes surface velocities. Here, with DopplerScatt, we mapped a 30 × 100 km domain over multiple days to unveil numerous 1–20 km ocean eddies, called submesoscale eddies, that evolve over a period of a few hours. The strong interactions between eddies generate horizontal velocity divergence, implying vertical velocities reaching 250 m day −1 at 40 m depth. The velocity field also produces horizontal dispersion of particles over a distance of 50 km within 12 h, which rapidly fills the turbulent eddy field. These observations suggest that submesoscale ocean turbulence may profoundly affect the vertical transport of heat, carbon, and important climatic gases between the atmosphere and the ocean interior, as well as the horizontal dispersion of tracers and particles. As such, submesoscale ocean eddies are a critical element of Earth’s climate system. Submesoscale eddies in the upper ocean play a critical role in the vertical transport and dispersion of ocean properties, including heat, nutrients, and carbon, making them essential for regulating the Earth’s climate system, according to results from the new airborne Doppler Scatterometer.