Acoustic tomography as a component of the Fram Strait observing system

2012 ◽  
Vol 132 (3) ◽  
pp. 1914-1914
Author(s):  
Brian D. Dushaw ◽  
Hanne Sagen ◽  
Stein Sandven ◽  
Peter Worcester
Keyword(s):  
Acoustic Tomography ◽  
Fram Strait

scholarly journals Time series of temperature in Fram Strait determined from the 2008–2009 DAMOCLES acoustic tomography measurements and an ocean model

2016 ◽  
Vol 121 (7) ◽  
pp. 4601-4617 ◽  
Author(s):  
Hanne Sagen ◽  
Brian D. Dushaw ◽  
Emmanuel K. Skarsoulis ◽  
Dany Dumont ◽  
Matthew A. Dzieciuch ◽  
...  
Keyword(s):  
Time Series ◽  
Ocean Model ◽  
Acoustic Tomography ◽  
Fram Strait

Ocean acoustic tomography: Travel‐time inversion in the eastern Fram Strait

2008 ◽  
Vol 123 (5) ◽  
pp. 2991-2991
Author(s):  
Emmanuel Skarsoulis ◽  
George Piperakis ◽  
Michael Kalogerakis ◽  
Hanne Sagen
Keyword(s):  
Travel Time ◽  
Acoustic Tomography ◽  
Time Inversion ◽  
Fram Strait ◽  
Travel Time Inversion ◽  
Ocean Acoustic Tomography

A Comparative Study of Moored/Point and Acoustic Tomography/Integral Observations of Sound Speed in Fram Strait Using Objective Mapping Techniques

2016 ◽  
Vol 33 (10) ◽  
pp. 2079-2093 ◽  
Author(s):  
Brian D. Dushaw ◽  
Hanne Sagen
Keyword(s):  
Sound Speed ◽  
Heat Content ◽  
Ocean Model ◽  
The Arctic ◽  
Mooring Line ◽  
Acoustic Tomography ◽  
Fram Strait ◽  
Data Types ◽  
Parameterized Model ◽  
Ocean Environment

AbstractEstimation of the exchange of seawater of various properties between the Arctic and North Atlantic Oceans presents a challenging observational problem. The strong current systems within Fram Strait induce recirculations and a turbulent ocean environment dominated by mesoscale variations of 4–10-km scale. By employing a simple parameterized model for mesoscale variability within Fram Strait, the authors examine the ability of a line array of closely spaced moorings and an acoustic tomography line to measure the average sound speed, a proxy variable for ocean temperature or heat content. Objective maps are employed to quantify the uncertainties resulting from the different measurement approaches. While measurements by a mooring line and tomography result in similar uncertainties in estimations of range- and depth-averaged sound speed, the combination of the two approaches gives uncertainties 3 times smaller. The two measurements are sufficiently different as to be complementary; one measurement provides resolution for the aspects of the temperature section that the other misses. The parameterized model and its assumptions as to the magnitudes and scales of variability were tested by application to a hydrographic section across Fram Strait measured in 2011. This study supports the deployment of the 2013–16 Arctic Ocean under Melting Ice (UNDER-ICE) network of tomographic transceivers spanning the ongoing moored array line across Fram Strait. Optimal estimation for this ocean environment may require combining disparate data types as constraints on a numerical ocean model using data assimilation.

The Fram Strait acoustic tomography system

2008 ◽  
Vol 123 (5) ◽  
pp. 2991-2991 ◽  
Author(s):  
Hanne Sagen ◽  
Stein Sandven ◽  
Peter Worcester ◽  
Matthew Dzieciuch ◽  
Emmanuel Skarsoulis
Keyword(s):  
Acoustic Tomography ◽  
Fram Strait ◽  
Tomography System

MAPPING TIDAL CURRENTS AND RESIDUAL CURRENTS BY USE OF COASTAL ACOUSTIC TOMOGRAPHY

2017 ◽  
Author(s):  
Xiao-Hua Zhu ◽  
Xiao-Hua Zhu ◽  
Ze-Nan Zhu ◽  
Ze-Nan Zhu ◽  
Xinyu Guo ◽  
...  
Keyword(s):  
Shallow Water ◽  
Shallow Water Equations ◽  
Mean Amplitude ◽  
Momentum Equation ◽  
Tidal Currents ◽  
Acoustic Tomography ◽  
Mean Values ◽  
Residual Currents ◽  
Water Depths ◽  
Deep Area

A coastal acoustic tomography (CAT) experiment for mapping the tidal currents in the Zhitouyang Bay was successfully carried out with seven acoustic stations during July 12 to 13, 2009. The horizontal distributions of tidal current in the tomography domain are calculated by the inverse analysis in which the travel time differences for sound traveling reciprocally are used as data. Spatial mean amplitude ratios M2 : M4 : M6 are 1.00 : 0.15 : 0.11. The shallow-water equations are used to analyze the generation mechanisms of M4 and M6. In the deep area, velocity amplitudes of M4 measured by CAT agree well with those of M4 predicted by the advection terms in the shallow water equations, indicating that M4 in the deep area where water depths are larger than 60 m is predominantly generated by the advection terms. M6 measured by CAT and M6 predicted by the nonlinear quadratic bottom friction terms agree well in the area where water depths are less than 20 m, indicating that friction mechanisms are predominant for generating M6 in the shallow area. Dynamic analysis of the residual currents using the tidally averaged momentum equation shows that spatial mean values of the horizontal pressure gradient due to residual sea level and of the advection of residual currents together contribute about 75% of the spatial mean values of the advection by the tidal currents, indicating that residual currents in this bay are induced mainly by the nonlinear effects of tidal currents.

Acoustic Tomography Applied to Water Flow in Unsaturated Soils

2004 ◽  
Vol 3 (1) ◽  
pp. 288
Author(s):  
Andreas Blum ◽  
Ivo Flammer ◽  
Thomas Friedli ◽  
Peter Germann
Keyword(s):  
Water Flow ◽  
Unsaturated Soils ◽  
Acoustic Tomography
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