Finescale Structure and Dynamics of the Gulf Stream

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

While the significance of the Gulf Stream to the global climate system has long been recognized, subsurface observations that resolve its variability and dynamics are limited. Understanding the dynamics of the Gulf Stream under the current climate is a critical first step, and this study will contribute significantly to advancing knowledge of the fine scale structure, dynamics, and stability of the Gulf Stream and may shed light on western boundary currents in other basins. Estimates of subsurface Gulf Stream structure and variability will serve as targets for modeling efforts. Observations from this program will be made available in near-real time for use in operational numerical models where they have demonstrated impacts. Concurrent biological and physical measurements within the Gulf Stream collected during this program are likely to lead to opportunities for interdisciplinary studies. Outreach and education activities will include involvement with established undergraduate summer programs at the Woods Hole Oceanographic Institution, inclusion of new findings in graduate instruction through the Massachusetts Institute of Technology-Woods Hole Oceanographic Institution Joint Program, and showcasing of the research and underwater gliders at public events. The project will train and support one graduate student. Building on a successful 1-year pilot study, this project will use autonomous underwater gliders to collect high-resolution measurements of temperature, salinity, currents, and biological indicators within the Gulf Stream between southern Florida and New England for two years. At the conclusion of the field program, an unprecedented set of approximately 150 cross-Gulf Stream transects through the upper 1000 m over a three-year period will offer a unique opportunity to examine the fine scale structure and dynamics of the Gulf Stream. This project will focus on 1) seasonal and along-stream variability in Gulf Stream structure, including potential vorticity and implications for stability; 2) large-amplitude internal waves and thick bottom mixed layers that are formed when the Gulf Stream flows over the continental margin upstream of Cape Hatteras; and 3) quantifying the effects of horizontal stirring using along-isopycnal temperature, salinity, and potential vorticity as passive tracers. This research will stimulate future theoretical and analytical advances in the understanding of western boundary currents and their role in the Earth's climate system.