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Darrell Jackson

Principal Engineer Emeritus

Research Professor Emeritus, Electrical Engineering






Darrell Jackson is engaged in theoretical and experimental research in ocean acoustics. This includes random scattering in the ocean, acoustic remote sensing of the ocean bottom, and related signal processing methods.

Department Affiliation



B.S. Electrical Engineering, University of Washington, 1960

M.S. Electrical Engineering, University of Washington, 1963

Ph.D. Electrical Engineering, University of Washington, 1966

Ph.D. Physics, California Institute of Technology, 1977


2000-present and while at APL-UW

Sonar observations of heat flux of diffuse hydrothermal flows

Jackson, D., K. Bemis, G. Xu, and A. Ivakin, "Sonar observations of heat flux of diffuse hydrothermal flows," Earth Space Sci., 9, doi:10.1029/2021EA001974, 2022.

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1 Oct 2022

Previous work using multibeam sonar to map diffuse hydrothermal flows is extended to estimate the heat output of diffuse flows. In the first step toward inversion, temperature statistics are obtained from sonar data and compared to thermistor data in order to set the value of an empirical constant. Finally, a simple model is used to obtain heat-flux density from sonar-derived temperature statistics. The method is applied to data from the Cabled Observatory Vent Imaging Sonar (COVIS) deployed on the Ocean Observatories Initiative's Regional Cabled Array at the ASHES vent field on Axial Seamount. Inversion results are presented as maps of heat-flux density in MW/m2 and as time series of heat-flux density averaged over COVIS' field of view.

Acoustic and in-situ observations of deep seafloor hydrothermal discharge: An OOI Cabled Array ASHES vent field case study

Xu, G., K. Bemis, D. Jackson, and A. Ivakin, "Acoustic and in-situ observations of deep seafloor hydrothermal discharge: An OOI Cabled Array ASHES vent field case study," Earth Space Sci., 8, doi:10.1029/2020EA001269, 2021.

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1 Mar 2021

The Cabled Observatory Vent Imaging Sonar (COVIS) was installed on the Ocean Observatories Initiative's Regional Cabled Array observatory at ASHES hydrothermal vent field on Axial Seamount in July 2018. The acoustic backscatter data recorded by COVIS in August–September 2018, in conjunction with in situ temperature measurements, are used to showcase and verify the use of COVIS for long‐term, quantitative monitoring of hydrothermal discharge. Specifically, sonar data processing generates three‐dimensional backscatter images of the buoyant plumes above major sulfide structures and two‐dimensional maps of diffuse flows within COVIS's field‐of‐view. The backscatter images show substantial changes of plume appearance and orientation that mostly reflect plume bending in the presence of ambient currents and potentially the variations of outflow fluxes. The intensity of acoustic backscatter decreases significantly for highly bent plumes as compared to nearly vertical plumes, reflecting enhanced mixing of plume fluids with seawater driven by ambient currents. A forward model of acoustic backscatter from a buoyancy‐driven plume developed in this study yields a reasonable match with the observation, which paves the way for inversely estimating the source heat flux of a hydrothermal plume from acoustic backscatter measurements. The acoustic observations of diffuse flows show large temporal variations on time scales of hours to days, especially at tidal frequencies, but no apparent long‐term trend. These findings demonstrate COVIS's ability to quantitatively monitor hydrothermal discharge from both focused and diffuse sources to provide the research community with key observational data for studying the linkage of hydrothermal activity with oceanic and geological processes.

Scattering from layered seafloors: Comparisons between theory and integral equations

Olson, D.R., and D. Jackson, "Scattering from layered seafloors: Comparisons between theory and integral equations," J. Acoust. Soc. Am., 148, 2086-2095, doi:10.1121/10.0002164, 2020.

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1 Oct 2020

Acoustic scattering from layered seafloors exhibits dependence on both the mean geoacoustic layering, as well as the roughness properties of each layer. Several theoretical treatments of this environment exist, including the small roughness perturbation approximation, the Kirchhoff approximation, and three different versions of the small slope approximation. All of these models give different results for the scattering cross section and coherent reflection coefficient, and there is currently no way to distinguish which model is the most correct. In this work, an integral equation for scattering from a layered seafloor with rough interfaces is presented, and compared with small roughness perturbation method, and two of the small slope approximations. It is found that the most recent small slope approximation by Jackson and Olson [J. Acoust. Soc. Am. 147(1), 56–73 (2020)] is the most accurate when the root-mean-square (rms) roughness is large, and some models are in close agreement with each other when the rms roughness is small.

More Publications

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center