Acoustic Tomography in Fram Strait and Artic Ocean
Abstract
Acoustic Tomography in Fram Strait and Arctic Ocean Brian Dushaw The Nansen Environmental and Remote Sensing Center Thormøhlens gate 47 N-5006, Bergen, Norway +1 (206) 788-5604, +47 905-943-87 brian.dushaw@gmail.com, brian.dushaw@nersc.no Summary: Fram Strait plays a critical role in the transport of heat and salt between the Arctic and Atlantic and the relation of those transports to the changing Arctic climate and ice coverage. Mass and heat flux through Fram Strait drives about 1/3 of the heat content variability of the Arctic. Transports through Fram Strait greatly influence Arctic ice cover, and these transports are highly variable. Accurate measures of these transports are therefore critical to understanding the nature of the changing Arctic and its ice cover. The Nansen Center seeks to exploit acoustic remote sensing to better quantify and understand the Arctic environment. The acoustic observations in Fram Strait include the ACOBAR and UNDER-ICE projects. The extraordinary nature of variability within Fram Strait corresponds to extraordinary sound speed variations. Understanding the nuances of the acoustic propagation is prerequisite to employing tomography in Fram Strait. This is the "forward problem," the first requirement to obtain inverse solutions. Given the peculiarities of acoustic data obtained during the observational programs, creative approachs to the inverse of these acoustic data are required to obtain conventional estimates for temperatures from tomography. Quantitative studies employing disparate data types and inverse techniques will be used to determine the relative information values of the data types for an observational program. Numerical ocean models have three roles in this project. First, high-resolution models capture the some of the nature of the complicated sound speed environment of Fram Strait, so models are helpful in understanding the nature of the acoustic propagation. Second, these models show essential characteristics of how the ocean is behaving within Fram Strait, so they are essential tools for developing a good oceanographic picture of what is occurring. Third, while the overall aim of modeling programs is to develop accurate descriptions of how the ocean is behaving, models still fail in essential details. Through data assimilation, the acoustic data offer unique model constraints on the mean temperatures and other properties within Fram Strait. This project will contribute to the challenging prospect of employing acoustic tomography data for constraining numerical ocean models within Fram Strait by data assimilation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512186
Entities
People
- Brian D. Dushaw
Organizations
- Nansen Environmental and Remote Sensing Center
- Office of Naval Research
- United States Navy