High-Frequency Radar Observations of Ocean Surface Currents

Jeffrey D. Paduan, Libe Washburn
2013 Annual Review of Marine Science  
This article reviews the discovery, development, and use of high-frequency (HF) radio wave backscatter in oceanography. HF radars, as the instruments are commonly called, remotely measure ocean surface currents by exploiting a Bragg resonant backscatter phenomenon. Electromagnetic waves in the HF band (3-30 MHz) have wavelengths that are commensurate with wind-driven gravity waves on the ocean surface; the ocean waves whose wavelengths are exactly half as long as those of the broadcast radio
more » ... es are responsible for the resonant backscatter. Networks of HF radar systems are capable of mapping surface currents hourly out to ranges approaching 200 km with a horizontal resolution of a few kilometers. Such information has many uses, including search and rescue support and oil-spill mitigation in real time and larval population connectivity assessment when viewed over many years. Today, HF radar networks form the backbone of many ocean observing systems, and the data are assimilated into ocean circulation models.
doi:10.1146/annurev-marine-121211-172315 pmid:22809196 fatcat:m4cws7pg7vg2vomyephralbdgq