APL-UW Home

Jobs
About
Campus Map
Contact
Privacy
Intranet

Guangyu Xu

Research Scientist/Engineer - Senior

Email

guangyux@apl.uw.edu

Phone

206-543-6860

Research Interests

Guangyu Xu's research combines underwater acoustic and numerical modeling techniques to study fluid flows within both the seafloor and the ocean. Xu's scientific questions focus on: dynamics associated with seafloor hydrothermal discharge and its dispersal near a mid-ocean ridge, deep ocean flows and their interconnections with surface processes, sub-seafloor hydrothermal circulation, and acoustic seafloor characterization.

Department Affiliation

Acoustics

Education

B.S. Ocean Technology, Ocean University of China (Qingdao, Shandong Province, China), 2008

M.S. Marine Sciences, University of Georgia, 2010

Ph.D. Marine Sciences, Rutgers University, 2015

Publications

2000-present and while at APL-UW

Dispersion of deep-sea hydrothermal plumes at the Endeavour Segment of the Juan de Fuca Ridge: a multiscale numerical study

Xu, G., C.R. German, "Dispersion of deep-sea hydrothermal plumes at the Endeavour Segment of the Juan de Fuca Ridge: a multiscale numerical study," Front. Mar. Sci., 10, doi:10.3389/fmars.2023.1213470, 2023.

More Info

20 Jul 2023

A multiscale numerical framework has been developed to investigate the dispersion of deep-sea hydrothermal plumes that originate from the Endeavour Segment of the Juan de Fuca Ridge located in the Northeast Pacific. The analysis of simulation outputs presented in this study provides insights into the influences of tidal forcing and the buoyancy flux associated with hydrothermal venting on ocean circulation and plume dispersion in the presence of pronounced seafloor topography. The results indicate that tidal forcing drives anti-cyclonic circulation near the ridge-axis, while hydrothermal venting induces cyclonic circulation around vent fields within the axial rift valley. Tidal forcing has a notable impact on plume dispersion, particularly near the large topographic features to the north of the Endeavour Segment. Furthermore, plume dispersion exhibits notable inter-annual variability, with a northbound trajectory in 2016 and a southbound trajectory in 2021. The study also reveals that both buoyancy fluxes and tidal forcing enhance the mixing of hydrothermal plumes with ambient seawater.

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.

More Info

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.

More Info

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.

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
Close

 

Close