Nonlinear Internal Waves: Test of the Inverted Echo Sounder

2007 ◽  
Author(s):  
David M. Farmer
Keyword(s):  
Internal Waves ◽  
Nonlinear Internal Waves ◽  
Inverted Echo Sounder ◽  
Echo Sounder

scholarly journals Acoustical Measurement of Nonlinear Internal Waves Using the Inverted Echo Sounder

2009 ◽  
Vol 26 (10) ◽  
pp. 2228-2242 ◽  
Author(s):  
Qiang Li ◽  
David M. Farmer ◽  
Timothy F. Duda ◽  
Steve Ramp
Keyword(s):  
Surface Roughness ◽  
Wind Speed ◽  
Internal Waves ◽  
Thermal Structure ◽  
Sea Surface ◽  
Model Calculations ◽  
Nonlinear Internal Waves ◽  
Instrument Performance ◽  
Inverted Echo Sounder ◽  
Echo Sounder

Abstract The performance of pressure sensor–equipped inverted echo sounders for monitoring nonlinear internal waves is examined. The inverted echo sounder measures the round-trip acoustic travel time from the sea floor to the sea surface and thus acquires vertically integrated information on the thermal structure, from which the first baroclinic mode of thermocline motion may be inferred. This application of the technology differs from previous uses in that the wave period (∼30 min) is short, requiring a more rapid transmission rate and a different approach to the analysis. Sources of error affecting instrument performance include tidal effects, barotropic adjustment to internal waves, ambient acoustic noise, and sea surface roughness. The latter two effects are explored with a simulation that includes surface wave reconstruction, acoustic scattering based on the Kirchhoff approximation, wind-generated noise, sound propagation, and the instrument’s signal processing circuitry. Bias is introduced as a function of wind speed, but the simulation provides a basis for bias correction. The assumption that the waves do not significantly affect the mean stratification allows for a focus on the dynamic response. Model calculations are compared with observations in the South China Sea by using nearby temperature measurements to provide a test of instrument performance. After applying corrections for ambient noise and surface roughness effects, the inverted echo sounder exhibits an RMS variability of approximately 4 m in the estimated depth of the eigenfunction maximum in the wind speed range 0 ≤ U10 ≤ 10 m s−1. This uncertainty may be compared with isopycnal excursions for nonlinear internal waves of 100 m, showing that the observational approach is effective for measurements of nonlinear internal waves in this environment.

Northwest Atlantic REX inverted echo sounder location: Acoustic range data

1986 ◽  
Vol 10 (2) ◽  
pp. 169-193 ◽  
Author(s):  
Gary A. Ransford ◽  
Juliette W. Ioup ◽  
Jim L. Mitchell
Keyword(s):  
Range Data ◽  
Northwest Atlantic ◽  
Inverted Echo Sounder ◽  
Echo Sounder

The first near real-time inverted echo sounder observation in the South China Sea

2021 ◽  
Vol 40 (6) ◽  
pp. 129-130
Author(s):  
Ruixiang Zhao ◽  
Xiaohua Zhu ◽  
Chuanzheng Zhang ◽  
Hua Zheng
Keyword(s):  
South China Sea ◽  
Real Time ◽  
South China ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Inverted Echo Sounder ◽  
Echo Sounder
Sign in / Sign up

Export Citation Format

Share Document