Loop Current Hyperactivity: Analysis of In Situ Measurements in the Gulf of Mexico

摘要

Starting in June 2014, ocean currents in the Gulf of Mexico became uncharacteristically detrimental tornoffshore operations. An unprecedented event of extreme Loop Current activity, not only in spatial andrntemporal extent but also in current intensity and vertical structure, was observed and documented for arnyear and half. The unusual activity was attributed to either increased inflow from the Caribbean Searnthrough the Yucatan Channel or amplification caused by local frontal cyclonic eddies. Anticyclonic eddiesrnthat shed from the Loop Current during this ongoing event maintained relatively large structures followingrntheir initial detachments and exhibited reconnections with the Loop Current within days to weeks ofrnseparation. This process was repeated by several eddies more than twice. In situ measurements indicatedrnfrequently reoccurring ocean current intensities upwards of 3.0 knots sustained for several weeks at a timernwith peak observed amplitudes over 4.0 knots. In this study, we present data collected from ADCPrnmeasurements and an extensive network of drifting buoys in correlation with daily frontal analyses basedrnon all available in situ data and satellite imagery – both public and proprietary. The Loop Current and eachrneddy shed during this period is discussed with emphasis on structure, intensity, and migration pattern.rnInvestigation was made into a possible link to El Niño and/or other large-scale air-sea phenomena andrnteleconnections; however, the root cause(s) for the circulation hyperactivity in the Gulf, if any, remainsrnunknown. The study concludes with lessons learned and a brief description of long-term forecast modelingrnefforts to mitigate risk and enhance safety and efficiency in offshore operations.