Study Tests STARRS Imaging of Short-Lived Small-Scale Dispersion on Ocean’s Surface
August 15, 2019
Researchers described field methods and observations using the Ship-Tethered Aerostat Remote Sensing System (STARSS) to better understand how buoyant material moves and disperses on the ocean’s surface. Using algorithms based on geo-rectified imagery, the STARSS successfully quantified small-scale and high-frequency surface dispersion in an open-ocean environment and improved observational diffusivity estimates in the 3 to 40 meters scale. The system captured anisotropic dispersion along a density front and distinguished bamboo plates from ephemeral features like sun glitter and whitecaps. This study is the first observational attempt to simultaneously resolve surface ocean Lagrangian dispersion at oceanic boundary layer scales and submesoscales in an offshore, deep-ocean setting. These methods can be replicated and integrated into existing and future field campaigns using sensors and aerial platforms that satisfy the STARSS requirements outlined in the study.
The researchers published their findings in Frontiers in Marine Science: Surface ocean dispersion observations from the ship-tethered aerostat remote sensing system.
After Deepwater Horizon, it became evident that improved transport and dispersion forecasts at the air-sea interface (a difficult region to measure) and at large spatial ranges (meters to kilometers) and temporal ranges (hours to months) were needed. Recent observational campaigns that focused on submesoscale transport and mixing have improved velocity estimates, data assimilating models, and understanding of turbulence (PNAS Poje et al., 2014, JTEC Berta et al., 2015, JGR Oceans Jacobs et al., 2015, and PNAS D’Asaro et al., 2018); however, relatively few in situ studies have quantified near-surface velocities at oceanic boundary layer scales. Traditional ocean observation tools (e.g., drifters, ships, and satellites) have limited ability to measure velocities at the air-sea interface and resolve dispersion at these scales.
“Observing ocean transport and mixing at the surface of the ocean is difficult, especially when you’re far from land where there are no fixed reference points,” explained study author Dan Carlson. “The difficulty increases when you want to observe short-lived (seconds to hours) motion at small spatial scales (meters to hundreds of meters), but these environmental conditions and scales are very relevant to the drift and spread of small patches of oil.”