Four Current Meter Models Compared in Strong Currents in Drake Passage

• Published in: Journal of atmospheric and oceanic technology 2013-10, Vol.30 (10), p.2465-2477
• Main Authors: Watts, DRandolph, Kennelly, Maureen A, Donohue, Kathleen A, Tracey, Karen L, Chereskin, Teresa K, Weller, Robert A, Victoria, Ivan
• Format: Article
• Language: English
• Subjects: Current meters; Diurnal variations; Marine; Mathematical analysis; Measurement techniques; Measuring instruments; Meters; Mooring; Ocean currents; RCM; Recording; Vectors (mathematics); Velocity; Velocity measurement
• ISSN: 0739-0572; 1520-0426
• DOI: 10.1175/JTECH-D-13-00032.1

Seven current meters representing four models on a stiffly buoyed mooring were placed for an 11-month deployment to intercompare their velocity measurements: two vector-measuring current meters (VMCMs), two Aanderaa recording current meter (RCM) 11s, two Aanderaa SEAGUARDs, and a Nortek Aquadopp. The current meters were placed 6-m apart from each other at about 4000-m depth in an area of Drake Passage expected to have strong currents, nearly independent of depth near the bottom. Two high-current events occurred in bursts of semidiurnal pulses lasting several days, one with peak speeds up to 67 cm s1 and the other above 35 cm s1. The current-speed measurements all agreed within 7% of the median value when vector averaged over simultaneous time intervals. The VMCMs, chosen as the reference measurements, were found to measure the median of the mean-current magnitudes. The RCM11 and SEAGUARD current speeds agreed within 2% of the median at higher speeds (3567 cm s1), whereas in lower speed ranges (035 cm s1) the vector-averaged speeds for the RCM11 and SEAGUARD were 4%5% lower and 3%5% higher than the median, respectively. The shorter-record Aquadopp current speeds were about 6% higher than the VMCMs over the range (040 cm s1) encountered.