Lateral Coherence and Mixing in the Coastal Ocean: Adaptive Sampling using Gliders
Abstract
Lateral mixing is driven through the interplay between finescale isopycnal stirring (shear + strain) and small-scale diapycnal turbulence. We seek to understand this interplay within highly anisotropic coherent structures, such as fronts, jets, eddies and filaments, which likely control lateral dispersion in both coastal and open ocean. These structures evolve yet are often persistent on O (3 day) timescales, so are ideally suited to be adaptively sampled by autonomous gliders that actively report both turbulent and finescale statistics. As part of a coordinated effort to quantify the meso- through micro-scale processes driving lateral dispersion, we plan to deploy 4 AUV gliders to perform intensive, adaptive surveys. OSU autonomous gliders will capture the interplay between shear, strain, and turbulence over a wide range of scales. In conjunction with ship-based dye release experiments, adaptive glider sampling will substantially increase the synoptic coverage of the dye surveys, providing a more complete description of the spread and dispersion of the dye. Microstructure sensors will allow for the quantification of small-scale mixing and its dynamical feedback to meso and sub-mesoscale flows. ADCP imaging of water-column velocity will (i) characterize the features driving fluid dispersion, (ii) help build better turbulence parameterizations in anisotropic environments, and (iii) will provide enhanced tracking capabilities for lateral coherence calculations. The scarcity of synoptic observations in the past has made it impossible to detangle the lateral and vertical processes. Adaptive sampling with multiple gliders in multiple locations for extended durations will provide the detailed statistics necessary for the community to make progress.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2011
- Accession Number
- ADA557113
Entities
People
- James N. Moum
- John A. Barth
- Jonathan D. Nash
- R. K. Shearman
Organizations
- Oregon State University