Abstract
The Sub-Mesoscale Ocean Dynamics Experiment (S-MODE) is a NASA Earth Ventures Suborbital investigation designed to test the hypothesis that oceanic frontogenesis and the kilometer-scale (“submesoscale”) instabilities that accompany it make important contributions to vertical exchange of climate and biological variables in the upper ocean. These processes have been difficult to resolve in observations, making model validation challenging. A necessary step toward testing the hypothesis was to make accurate measurements of upper-ocean velocity fields over a broad range of scales and to relate them to the observed variability of vertical transport and surface forcing. A further goal was to examine the relationship between surface velocity, temperature and chlorophyll measured by remote sensing, and their depth-dependent distributions, within and beneath the surface boundary layer. To achieve these goals, we used aircraft-based remote sensing, satellite remote sensing, ships, drifter deployments, and a fleet of autonomous vehicles. The observational component of S-MODE consisted of three campaigns, all conducted in the Pacific Ocean approximately 100 km west of San Francisco during 2021-2023 fall and spring. S-MODE was enabled by recent developments in remote sensing technology that allowed operational airborne observation of ocean surface velocity fields and by advances in autonomous instrumentation that allowed coordinated sampling with dozens of uncrewed vehicles at sea. The coordinated use of remote sensing measurements from three aircraft with arrays of remotely operated vehicles and other in situ measurements is a major novelty of S-MODE. All S-MODE data is freely available, and its use is encouraged.
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