Ocean Observing in the 4th Dimension--Using Autonomous Gliders for Operational Surveillance of the Gulf of Mexico

摘要

The ocean circulation in the Gulf of Mexico is highly dynamic in four dimensions (4D). The circulation varies throughoutrnthe interconnected shelf, slope, and deep ocean domains (3 dimensions) and varies greatly in time (the 4th dimension).rnObtaining timely, comprehensive, and accurate forecasting of this 4D system remains a challenge for operators on the outerrncontinental shelf (OCS). Long-range autonomous underwater gliding vehicles (AUGVs) enable collection of high spatialrnresolution sections through the ocean repeatedly, autonomously, and at a very low cost compared to conventional methods.rnUsing these new tools, in-situ data can be continuously assessed to provide a more integrated description of the ocean state.rnWe describe a series of glider observations obtained during extended (3.4 months) observational campaigns in the easternrnGulf of Mexico. One survey period took place from April-August 2011, covered a linear distance of 1400 nm (2700 km),rnand collected over 1000 vertical profiles to 1000 m. The deployment spanned the Loop Current (LC) growth phase andrndetachment of Eddy Hadal. Several cross-sections were obtained through the LC front, cyclonic frontal eddies, and in closernproximity to working platforms in lease areas of the NGOM slope. The in-situ fields of ocean density help to delineate thernsubsurface boundaries of these dynamic features, and their geostrophic velocity structure can be inferred from lateral densityrnvariations. Sustained in-situ glider observations throughout the eastern Gulf of Mexico will improve the knowledge andrnforecasting vital for efficient day-to-day operational management decisions of the offshore petroleum industry.