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Front. Mar. Sci. | doi: 10.3389/fmars.2018.00479

Surface Ocean Dispersion Observations from the Ship-Tethered Aerostat Remote Sensing System

 Daniel F. Carlson1*, Tamay Ozgokmen2,  Guillaume Novelli2, Cedric Guigand2,  Henry Chang3,  Baylor Fox-Kemper4,  Jean Mensa5, Sanchit Mehta2, Erick Fredj6,  Helga Huntley3,  A.D. Kirwan3,  Maristella Berta7, Mike Rebozo2,  Milan Curcic8,  Ed Ryan2, Björn Lund9, Brian Haus2,  Cameron Hunt10, Shuyi Chen8,  Laura Bracken2 and  Jochen Horstmann11
  • 1Earth, Ocean, and Atmospheric Science, Florida State University, United States
  • 2Rosenstiel School of Marine and Atmospheric Science, University of Miami, United States
  • 3School of Marine Science and Policy, University of Delaware, United States
  • 4Department of Earth, Environmental and Planetary Science, Brown University, United States
  • 5Yale University, United States
  • 6Jerusalem College of Technology, Israel
  • 7Italian National Research Council, Italy
  • 8University of Washington, United States
  • 9Center for Southeastern Tropical Advanced Remote Sensing, University of Miami, United States
  • 10Defensewerx, United States
  • 11Department of Radar Hydrography,, Helmholtz Centre for Materials and Coastal Research (HZG), Germany

Oil slicks and sheens reside at the air-sea interface, a region of the ocean that is notoriously difficult to measure and, therefore, little is known about the velocity field at the sea surface. The Ship-Tethered Aerostat Remote Sensing System (STARSS) was developed to measure Lagrangian velocities at the air-sea interface by tracking the transport and dispersion of hundreds of drift cards in the field of view of a high-resolution aerial imaging system. The camera had a field of view of approximately 300 m X 200 m and images were obtained every 15 seconds over periods of up to 3 hours during a series of experiments in the northern Gulf of Mexico in January-February 2016. STARSS was equipped with a GPS and inertial navigation system (INS) that was used to directly georectify the aerial images. A relative rectification technique was developed that translates and rotates the drift cards to minimize the total movement of all drift cards from one frame to the next. Rectified drift card positions were used to quantify scale-dependent dispersion by computing relative dispersion, relative diffusivity, and velocity structure functions. STARSS was part of a nested observational framework, which included deployments of large numbers of GPS-tracked surface drifters from two ships, in situ ocean measurements, and X-band radar observations of surface currents. STARSS operations were supported by weather forecasts from a high-resolution coupled atmosphere-wave-ocean model. Here we describe the STARSS system and image analysis techniques, and present results from an experiment that was conducted on a density front. To the best of our knowledge, these observations are the first of their kind and STARSS-like observations can be adopted into existing and planned oceanographic campaigns to produce a step-change in our understanding of small-scale and high-frequency variability at the air-sea interface.

Keywords: Surface dispersion, Air-sea interface, Langmuir, Aerostat, Gulf of Mexico, oil spill, Drift cards, transport, particle tracking

Received: 22 Mar 2018; Accepted: 28 Nov 2018.

Edited by:

Gilles Reverdin, Center for the National Scientific Research (CNRS), France

Reviewed by:

Andrew Jessup, University of Washington, United States
Fabrice Ardhuin, UMR6523 Laboratoire d'Oceanographie Physique et Spatiale (LOPS), France  

Copyright: © 2018 Carlson, Ozgokmen, Novelli, Guigand, Chang, Fox-Kemper, Mensa, Mehta, Fredj, Huntley, Kirwan, Berta, Rebozo, Curcic, Ryan, Lund, Haus, Hunt, Chen, Bracken and Horstmann. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Daniel F. Carlson, Florida State University, Earth, Ocean, and Atmospheric Science, Tallahassee, 32306, Florida, United States, danfcarlson@gmail.com