APL-UW Home

Jobs
About
Campus Map
Contact
Privacy
Intranet

Jim Thomson

Senior Principal Oceanographer

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

Wave Glider Observations in the Southern Ocean

A Wave Glider autonomous surface vehicle will conduct a summer-season experiment to investigate ocean–shelf exchange on the West Antarctic Peninsula and frontal air–sea interaction over both the continental shelf and open ocean.

More Info

4 Sep 2019

Southern Ocean climate change is at the heart of the ocean's response to anthropogenic forcing. Variations in South Polar atmospheric circulation patterns, fluctuations in the strength and position of the Antarctic Circumpolar Current, and the intertwining intermediate deep water cells of the oceanic meridional overturning circulation have important impacts on the rate of ocean carbon sequestration, biological productivity, and the transport of heat to the melting continental ice shelves.

Wave Measurements at Ocean Weather Station PAPA

As part of a larger project to understand the impact of surface waves on the ocean mixed layer, APL-UW is measuring waves at Ocean Weather Station Papa, a long-term observational site at N 50°, W 145°.

29 Aug 2019

Coastal Ocean Dynamics in the Arctic — CODA

Arctic coastlines are eroding at rates of meters per year. As the whole Arctic shifts into a modern epoch of seasonal ice cover and warmer temperatures, Arctic coastal processes are shifting, too. The overall goal of this research is to improve scientific understanding of wave–ice–ocean interactions along the Arctic coast, with particular attention to the oceanographic parameters that affect erosion.

8 Jan 2019

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

Frazil ice growth and production during katabatic wind events in the Ross Sea, Antarctica

Thompson, L., M. Smith, J. Thomson, S. Stammerjohn, S. Ackley, and B. Loose, "Frazil ice growth and production during katabatic wind events in the Ross Sea, Antarctica," Cryosphere, 14, 3329-3347, doi:10.5194/tc-14-3329-2020, 2020.

More Info

6 Oct 2020

Katabatic winds in coastal polynyas expose the ocean to extreme heat loss, causing intense sea ice production and dense water formation around Antarctica throughout autumn and winter. The advancing sea ice pack, combined with high winds and low temperatures, has limited surface ocean observations of polynyas in winter, thereby impeding new insights into the evolution of these ice factories through the dark austral months. Here, we describe oceanic observations during multiple katabatic wind events during May 2017 in the Terra Nova Bay and Ross Sea polynyas. Wind speeds regularly exceeded 20 m s-1, air temperatures were below –25°C, and the oceanic mixed layer extended to 600 m. During these events, conductivity–temperature–depth (CTD) profiles revealed bulges of warm, salty water directly beneath the ocean surface and extending downwards tens of meters. These profiles reflect latent heat and salt release during unconsolidated frazil ice production, driven by atmospheric heat loss, a process that has rarely if ever been observed outside the laboratory. A simple salt budget suggests these anomalies reflect in situ frazil ice concentration that ranges from 13 to 266x10-3 kg m-3. Contemporaneous estimates of vertical mixing reveal rapid convection in these unstable density profiles and mixing lifetimes from 7 to 12 min. The individual estimates of ice production from the salt budget reveal the intensity of short-term ice production, up to 110 cm d-1 during the windiest events, and a seasonal average of 29 cm d-1. We further found that frazil ice production rates covary with wind speed and with location along the upstream–downstream length of the polynya. These measurements reveal that it is possible to indirectly observe and estimate the process of unconsolidated ice production in polynyas by measuring upper-ocean water column profiles. These vigorous ice production rates suggest frazil ice may be an important component in total polynya ice production.

Long-term Measurements of Ocean Waves and Sea Ice Draft in the Central Beaufort Sea

Thomson, J., "Long-term Measurements of Ocean Waves and Sea Ice Draft in the Central Beaufort Sea," Technical Memorandum, APL-UW TM 1-20, Applied Physics Laboratory, University of Washington, Seattle, 22 pp.

More Info

5 Oct 2020

An ongoing program has measured ocean surface waves and sea ice draft at two sites in the Beaufort Sea (western Arctic Ocean) since 2012. This report presents the measurements and processed data products available from 2012 to 2018. Ocean surface waves are observed each summer and autumn when sea ice retreats; observed range of significant wave heights is 0.5–4 m. Sea ice is observed the rest of the year; observed range of average draft is 0.5–5 m.

A unified breaking onset criterion for surface gravity water waves in arbitrary depth

Derakhti, M., J.T. Kirby, M.L. Banner, S.T. Grilli, and J. Thomson, "A unified breaking onset criterion for surface gravity water waves in arbitrary depth," J. Geophys. Res., 125, doi:10.1029/2019JC015886

More Info

1 Jul 2020

We investigate the validity and robustness of the Barthelemy et al. (2018, https://doi.org/10.1017/jfm.2018.93) wave‐breaking onset prediction framework for surface gravity water waves in arbitrary water depth, including shallow water breaking over varying bathymetry. We show that the Barthelemy et al. (2018) breaking onset criterion, which they validated for deep and intermediate water depths, also segregates breaking crests from nonbreaking crests in shallow water, with subsequent breaking always following the exceedance of their proposed generic breaking threshold. We consider a number of representative wave types, including regular, irregular, solitary, and focused waves, shoaling over idealized bed topographies including an idealized bar geometry and a mildly to steeply sloping planar beach. Our results show that the new breaking onset criterion is capable of detecting single and multiple breaking events in time and space in arbitrary water depth. Further, we show that the new generic criterion provides improved skill for signaling imminent breaking onset, relative to the available kinematic or geometric breaking onset criteria in the literature. In particular, the new criterion is suitable for use in wave‐resolving models that cannot intrinsically detect the onset of wave breaking.

More Publications

In The News

UW study finds disturbing climate change evidence in Arctic Ocean

KING5 News, Glenn Farley

A joint study between the University of Washington and University of Alaska has uncovered the presence of 'pancake ice' and tall waves in the Arctic Ocean. Photo: John Guillotte

21 Jan 2020

Warm ocean water delays sea ice for Alaska towns, wildlife

Associated Press, Dan Joling

In the new reality of the U.S. Arctic, open water is the November norm for the Chukchi. Instead of thick, years-old ice, researchers are studying waves and how they may pummel the northern Alaska coastline.

19 Nov 2019

Fall storms, coastal erosion focus of northern Alaska research cruise

UW News, Hannah Hickey

A University of Washington team is leaving to study how fall storms, dwindling sea ice and vulnerable coastlines might combine in a changing Arctic. The project leaves Thursday, Nov. 7, from Nome, Alaska in the Bering Strait to spend four weeks gathering data during the fall freeze-up season.

5 Nov 2019

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