Tracking the Evolution of Turbulence within the Submesoscale: Autonomous Profiling Float Observations
Abstract
Objectives: I propose to analyze the distribution of turbulence and submesoscale instabilities within the context of a dynamic mesos cale and internal wave field to determine which of the theorized mechanisms are critical for guiding the cascade of energy from subm esoscale currents to smaller scales and dissipation. Using observations from the Island Arc Turbulent Eddy Regional Exchange (ARCTER X) DRI, I specifically hope to address the question `How is the turbulence near submesoscale features modulated by the complex mesos cale, wind, and internal wave field in the ARCTERX region? Following this, I hope to evaluate how the mechanisms setting the turbul ence near submesoscale features evolve on seasonal timescales.Motivation: The oceanic submesoscale energy cascade is thought to be m odulated by numerous processes (i.e. submesoscale instabilities and interactions with internal waves) that themselves depend on fact ors such as the state of mesoscale field, wind conditions, and characteristics of the internal wave field. However, to date, few obs ervations capture the evolution of the submesoscale cascade and eventual dissipation within this complex context. Previous work has been impeded by the observational challenges of measuring the particular time (hours-days) and length (1s-10s km) scales associated with submesoscale currents, and therefore has either focused on regional variability or targeted individual fronts. These observatio nal limitations have made generalizing the observations to characterize the global submesoscale and develop parameterizations diffic ult. The proposed work aims to fill this gap in the ARCTERX region by taking advantage of recent technological and logistical advanc es that enable the deployment of large arrays of autonomous profiling floats with the capability to measure turbulence.Approach: The ARCTERX DRI includes two planned cruises in the western Pacific between the Luzon and Marianas Island Arcs. I propose, as an option , to deploy arrays of profiling EM-Apex floats during both cruises as part of the ARCTERX DRI. The EM-Apex floats measure temperatur e, salinity, velocity, and temperature microstructure (which can be used to infer turbulence). Planned deployments include 4-8 float arrays targeting a range of submesoscale features and environments, and a long-term array to capture the evolution of the submesosc ale with the seasons. Additionally, I plan on collaborating closely with the other ARCTERX profiling float and modeling PIs to devel op a comprehensive deployment strategy that will improve the accuracy of submesoscale and internal wave separation techniques.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 07, 2021
- Source ID
- N000142112866
Entities
People
- Caitlin Whalen
Organizations
- Office of Naval Research
- United States Navy
- University of Washington