Measurement Characteristics of Near-Surface Currents from Ultra-Thin Drifters, Drogued Drifters, and HF Radar
1
Center for Coastal and Marine Ecosystems, School of the Environment, Florida Agricultural and Mechanical University, Tallahassee, FL 32307, USA
2
Center for Ocean—Atmospheric Prediction Studies, Florida State University, Tallahassee, FL 32306, USA
3
Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
*
Author to whom correspondence should be addressed.
Remote Sens. 2018, 10(10), 1633; https://doi.org/10.3390/rs10101633
Received: 8 September 2018 / Revised: 2 October 2018 / Accepted: 9 October 2018 / Published: 14 October 2018
(This article belongs to the Special Issue Ocean Surface Currents: Progress in Remote Sensing and Validation)
Concurrent measurements by satellite tracked drifters of different hull and drogue configurations and coastal high-frequency radar reveal substantial differences in estimates of the near-surface velocity. These measurements are important for understanding and predicting material transport on the ocean surface as well as the vertical structure of the near-surface currents. These near-surface current observations were obtained during a field experiment in the northern Gulf of Mexico intended to test a new ultra-thin drifter design. During the experiment, thirty small cylindrical drifters with 5 cm height, twenty-eight similar drifters with 10 cm hull height, and fourteen drifters with 91 cm tall drogues centered at 100 cm depth were deployed within the footprint of coastal High-Frequency (HF) radar. Comparison of collocated velocity measurements reveals systematic differences in surface velocity estimates obtained from the different measurement techniques, as well as provides information on properties of the drifter behavior and near-surface shear. Results show that the HF radar velocity estimates had magnitudes significantly lower than the 5 cm and 10 cm drifter velocity of approximately 45% and 35%, respectively. The HF radar velocity magnitudes were similar to the drogued drifter velocity. Analysis of wave directional spectra measurements reveals that surface Stokes drift accounts for much of the velocity difference between the drogued drifters and the thin surface drifters except during times of wave breaking.
View Full-Text
Keywords:
surface drifters; surface currents; HF Radar
▼
Show Figures
Figure 1
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
MDPI and ACS Style
Morey, S.L.; Wienders, N.; Dukhovskoy, D.S.; Bourassa, M.A. Measurement Characteristics of Near-Surface Currents from Ultra-Thin Drifters, Drogued Drifters, and HF Radar. Remote Sens. 2018, 10, 1633.
Show more citation formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.
