APL-UW Home

Jobs
About
Campus Map
Contact
Privacy
Intranet

Jim Thomson

Senior Principal Oceanographer

Associate Professor, Civil and Environmental Engineering

Email

jthomson@apl.washington.edu

Phone

206-616-0858

Research Interests

Environmental Fluid Mechanics, Ocean Surface Waves, Marine Renewable Energy (tidal and wave), Coastal and Nearshore Processes, Ocean Instrumentation

Biosketch

Dr. Thomson studies waves, currents, and turbulence by combining field observations and remote sensing techniques

Education

B.A. Physics, Middlebury College, 2000

Ph.D. Physical Oceanography, MIT/WHOI, 2006

Projects

Stratified Ocean Dynamics of the Arctic — SODA

More Info

31 Oct 2016

Vertical and lateral water properties and density structure with the Arctic Ocean are intimately related to the ocean circulation, and have profound consequences for sea ice growth and retreat as well as for prpagation of acoustic energy at all scales. Our current understanding of the dynamics governing arctic upper ocean stratification and circulation derives largely from a period when extensive ice cover modulated the oceanic response to atmospheric forcing. Recently, however, there has been significant arctic warming, accompanied by changes in the extent, thickness distribution, and properties of the arctic sea ice cover. The need to understand these changes and their impact on arctic stratification and circulation, sea ice evolution, and the acoustic environment motivate this initiative.

Inner Shelf Dynamics

The inner shelf region begins just offshore of the surf zone, where breaking by surface gravity waves dominate, and extends inshore of the mid-shelf, where theoretical Ekman transport is fully realized. Our main goal is to provide provide improved understanding and prediction of this difficult environment. This will involve efforts to assess the influence of the different boundaries — surf zone, mid and outer shelf, air-water interface, and bed — on the flow, mixing and stratification of the inner shelf. We will also gain information and predictive understanding of remotely sensed surface processes and their connection to processes in the underlying water column.

15 Dec 2015

Measuring Vessel Wakes in Rich Passage, Puget Sound

APL-UW is using wave buoys to measure the wakes of Washington State DOT car ferries as they transit through Rich Passage. The objective is to assess the effectiveness of the speed reduction protocol through the passage, which is intended to minimize the vessel wake and minimize any subsequent changes to the shoreline.

22 Oct 2014

More Projects

Videos

Mapping Underwater Turbulence with Sound

More Info

9 Apr 2018

To dock at a terminal, large Washington State ferries use their powerful engines to brake, generating a lot of turbulence. Doppler sonar instruments are capturing an accurate picture of the turbulence field during docking procedures and how it affects terminal structures and the seabed. This research is a collaborative effort between APL-UW and the UW College of Engineering, Department of Civil and Environmental Engineering.

Marine Renewable Energy: Kvichak River Project

At a renewable energy site in the village of Igiugig, Alaska, an APL-UW and UW Mechanical Engineering team measured the flow around an electricity-generating turbine installed in the Kvichak River. They used modified SWIFT buoys and new technologies to measure the natural river turbulence as well as that produced by the turbine itself. The turbine has the capacity to generate a sizable share of the village's power needs.

25 Sep 2014

Ferry-Based Monitoring of Puget Sound Currents

Acoustic Doppler Current Profilers are installed on two Washington State Department of Transportation ferries to measure current velocities in a continuous transect along their routes. WSDOT ferries occupy strategic cross-sections where circulation and exchange of Puget Sound and Pacific Ocean waters occurs. A long and continuous time series will provide unprecedented measurements of water mass movement and transport between the basins.

9 May 2014

More Videos

Publications

2000-present and while at APL-UW

Rich Passage Tidal Energy Resource Characterization

Guerra, M., and J. Thomson, "Rich Passage Tidal Energy Resource Characterization," Technical Memorandum, APL-UW TM 2-18, Applied Physics Laboratory, University of Washington, Seattle, June 2018, 17 pp.

More Info

27 Jun 2018

Current and wave measurements were taken in Rich Passage in Puget Sound, WA, during fall 2014. Two instruments were deployed at the west end of Rich Passage; one measured currents and the other measured both currents and waves. The main objectives of the study were to measure waves generated by vessels transiting Rich Passage and to quantify the tidal energy resource of the channel. This report presents the analysis of the measured currents and an assessment of the hydrokinetic power available in Rich Passage.

Wave Energy Resource Characterization for San Nicholas Island

Johnson, N., and J. Thomson, "Wave Energy Resource Characterization for San Nicholas Island," Technical Memorandum, APL-UW TM 3-18, Applied Physics Laboratory, University of Washington, Seattle, June 2018, 37 pp.

More Info

27 Jun 2018

To characterize the wave energy resource for San Nicolas Island, off the coast of Southern California, wave data collected on three buoys located near the island were assembled from the Coastal Data Information Program (CDIP). These data were used to create joint probability density function plots and monthly-averaged plots of bulk parameters and energy spectra. Observed monthly-averaged bulk parameters and calculated power densities were compared to a wave energy atlas created by the National Renewable Energy Laboratory (NREL). Wave climatology products available from the Global Spectral Wave Climate (GLOSWAC) program were also compared with the climatology derived from the buoy data. Finally, regional spatial gradients in wave height and energy period were quantified using the difference between drifting Surface Wave Instrument Float with Tracking (SWIFT) measurements and the moored buoys, including a comparison of atlas values for these spatial gradients. In general, the atlas values agree well with the CDIP buoy data for significant wave height, but overestimate energy period and fail to capture wave direction trends. The atlas values overestimate observed power densities within a standard deviation of the observed values and capture observed variation in power density between different CDIP buoy locations. The atlas values underestimate observed spatial gradients for significant wave height and fail to capture observed spatial gradients for energy period.

Shipboard observations of the meteorology and near-surface environment during autumn freeze-up in the Beaufort/Chukchi seas

Persson, P.O.G., B. Blomquist, P. Guest, S. Stammerjohn, C. Fairall, L. Rainville, B. Lund, S. Ackley, and J. Thomson, "Shipboard observations of the meteorology and near-surface environment during autumn freeze-up in the Beaufort/Chukchi seas," J. Geophys. Res., EOR, doi:10.1029/2018JC013786, 2018.

More Info

12 Jun 2018

The collection and processing of shipboard air, ice, and ocean measurements from the Sea State field campaign in the Beaufort/Chukchi Seas in autumn 2015 are described and the data used to characterize the near‐surface freezeup environment. The number of parameters measured or derived is large and the location and time of year are unique. Analysis was done of transits through the new, growing ice and of ice edge periods. Through differential surface energy fluxes, the presence of new, thin sea ice (<50 cm) produces lower tropospheric air temperatures in the ice interior that average ~4°C colder than those over open water near the ice edge, resulting in an ice edge baroclinic zone. This temperature difference doubles by late October and produces thermodynamic and dynamic feedbacks. These include off‐ice, cold‐air advection leading to enhanced surface heat loss averaging ~200 W/m2 over the open water, formation of low‐level jets, suppression of the ice edge baroclinic zone, and enhanced ice drift. The interior ice growth rate is thermodynamically consistent with a surface heat loss of ~65 W/m2 to the atmosphere and a heat flux of several tens of W/m2 from the ocean below. Ice drift at times contributes to the southward advance of the autumn ice edge through off‐ice winds. The ocean thermohaline structure is highly variable and appears associated with bathymetric features, small‐scale upper‐ocean eddies, and the growing ice cover. Lower salinity under the ice interior compared to the nearby ice edge is an upper‐ocean impact of this thin ice cover.

More Publications

In The News

NSF funds wave-ice-ocean research along Arctic Coast

UW News, Civil & Environmental Engineering, Sarah McQuate

With Arctic coastlines quickly eroding, CEE faculty researchers have received $1 million from NSF's Office of Polar Programs to investigate how the interactions of waves, sea ice and the ocean affect coastal flooding.

16 Aug 2018

State investigators focus on nets plugged with mussels in Atlantic salmon net-pen failure

The Seattle Times, Lynda Mapes

Cooke Aquaculture’s maintenance practices at its collapsed Atlantic salmon farm at Cypress Island have drawn the attention of state investigators after nets were found fouled with mussels and other sea life. Fluid mechanics expert Jim Thomson notes that nets clogged with sea life create greater drag forces in the ocean currents, increasing the risk of structural failure.

26 Jan 2018

Partners in Extreme Wave Modeling

Engineering Out Loud Podcast, Jens Odegaard

How do you forecast and model huge waves in the open ocean? As part of the National Marine Renewable Energy Center, researchers at Oregon State University and the University of Washington are modeling and forecasting extreme waves to help inform wave energy technology.

25 Oct 2017

More News Items

Inventions

SWIFT v4

Record of Invention Number: 48200

Jim Thomson, Alex de Klerk, Joe Talbert

Disclosure

6 Nov 2017

SWIFT: Surface Wave Instrument Float with Tracking

Record of Invention Number: 46566

Jim Thomson, Alex De Klerk, Joe Talbert

Disclosure

24 Jun 2013

Heave Place Mooring for Wave Energy Conversion (WEC) via Tension Changes

Record of Invention Number: 46558

Jim Thomson, Alex De Klerk, Joe Talbert

Disclosure

19 Jun 2013

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