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Comparison of over‐the‐horizon radar surface‐current measurements in the Gulf of Mexico with simultaneous sea truth
Author(s) -
Harlan J. A.,
Georges T. M.,
Biggs D. C.
Publication year - 1998
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/98rs00747
Subject(s) - ocean gyre , radar , geology , current (fluid) , ocean current , acoustic doppler current profiler , remote sensing , geodesy , meteorology , oceanography , geography , telecommunications , computer science , subtropics , fishery , biology
On June 14, 1995, the U.S. Navy's Relocatable Over‐the‐Horizon Radar (ROTHR) west of Corpus Christi, Texas, mapped the radial component of ocean surface current with 15‐km resolution over a 230,000‐km 2 area in the Gulf of Mexico. Concurrently, an oceanographic research vessel measured near‐surface currents within part of the area illuminated by the radar, providing an opportunity to compare radarderived surface currents with in situ sea truth. The R/V Gyre , operated by Texas A&M University, twice traversed the Gulf of Mexico Loop Current while measuring current vectors with an acoustic Doppler current profiler (ADCP). We compared radar‐derived currents with currents measured in the uppermost ADCP bin (centered at 10‐m depth). If only radar data exceeding a quality threshold are considered, the rms difference in the radial currents measured by the two techniques is 27 cm s −1 . This difference most likely reflects the different sampling employed by these instruments, as well as unremoved ionospheric biases in the radar measurements.