Observations of three-dimensional frontal circulation using underwater gliders
Abstract
The circulation across oceanic fronts has been a topic of study for decades. The strain that causes fronts necessarily results in a cascade from mesoscales of the size of oceanic eddies down to sub-mesoscales of 1 kilometer size and smaller. In particular, the three-dimensional flow at these small scales may be intense. These flow are difficult to observe because of they are so small, intense, and intermittent. Here, we propose an observational plan using underwater gliders to address the following goals:??? to quantify mesoscale vertical velocity using survey data and diagnostic approaches??? to resolve submesoscale three-dimensional flow through direct measurement??? to observe internal wave vertical displacements around a frontWe propose to use Spray underwater gliders to observe these processes. Gliders will be used first to survey in a coordinated fashion. We plan to contribute six underwater gliders to a collaborative fleet that may be as large as 15 gliders. In survey mode, the 15 gliders would cover the same track length per unit time as a ship surveying with a towed vehicle. Deployments will last 100 days profiling to 1000 m, and gliders will carry sensors to measure temperature, salinity, velocity and chlorophyll fluorescence. Second, we propose to take advantage of our ability to park a Spray on an isopycnal in the region of a front, and measure vertical velocity through changes in pressure. We propose to use 3 gliders in this way, to produce a maximum of about 50three-day drifts. A proposed technical development is to equip the gliders with acoustic tracking equipment to realize complete 3-dimensional flow during the drifts.A timeline is as follows. Year 1 will include a pilot experiment in the Alboran Sea usingone glider and the development required to integrate acoustic navigation onto Spray gliders. Year 2 will include the remainder of acoustic integration, and intensive sampling using six gliders. A second intensive experiment will take place during year 3, again using six gliders. Years 4-5 will focus on analysis, and presentation and publication of results
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 10, 2018
- Source ID
- N000141812406
Entities
People
- Daniel L. Rudnick
Organizations
- Office of Naval Research
- United States Navy
- University of California, San Diego