APL-UW Home

Jobs
About
Campus Map
Contact
Privacy
Intranet

John Guthrie

Postdoctoral Scholar

Email

guthriej@apl.washington.edu

Phone

206-616-9972

Department Affiliation

Polar Science Center

Education

B.S. Mathematics, University of Puget Sound, 2002

M.S. Physical Oceanography, University of Washington - Seattle, 2012

Ph.D. Physical Oceanography, University of Washington - Seattle, 2016

Publications

2000-present and while at APL-UW

The cyclonic mode of Arctic Ocean circulation

Morison, J., R. Kwok, S. Dickinson, R. Andersen, C. Peralta-Ferriz, D. Morison, I. Rigor, S. Dewey, and J. Guthrie, "The cyclonic mode of Arctic Ocean circulation," J. Phys. Oceanogr., 51, 1053–1075, doi:10.1175/JPO-D-20-0190.1, 2021.

More Info

1 Apr 2021

Arctic Ocean surface circulation change should not be viewed as the strength of the anticyclonic Beaufort Gyre. While the Beaufort Gyre is a dominant feature of average Arctic Ocean surface circulation, empirical orthogonal function analysis of dynamic height (1950–1989) and satellite altimetry-derived dynamic ocean topography (2004–-2019) show the primary pattern of variability in its cyclonic mode is dominated by a depression of the sea surface and cyclonic surface circulation on the Russian side of the Arctic Ocean. Changes in surface circulation after AO maxima in 1989 and 2007–08 and after an AO minimum in 2010, indicate the cyclonic mode is forced by the Arctic Oscillation (AO) with a lag of about one year. Associated with a one standard deviation increase in the average AO starting in the early 1990s, Arctic Ocean surface circulation underwent a cyclonic shift evidenced by increased spatial-average vorticity. Under increased AO, the cyclonic mode complex also includes increased export of sea ice and near-surface freshwater, a changed path of Eurasian runoff, a freshened Beaufort Sea, and weakened cold halocline layer that insulates sea ice from Atlantic water heat, an impact compounded by increased Atlantic Water inflow and cyclonic circulation at depth. The cyclonic mode's connection with the AO is important because the AO is a major global scale climate index predicted to increase with global warming. Given the present bias in concentration of in situ measurements in the Beaufort Gyre and Transpolar Drift, a coordinated effort should be made to better observe the cyclonic mode.

Not just sea ice: Other factors important to near-inertial wave generation in the Arctic Ocean

Guthrie, J.D., J.H. Morison, "Not just sea ice: Other factors important to near-inertial wave generation in the Arctic Ocean," J. Geophys. Res., 48, doi:10.1029/2020GL090508, 2021.

More Info

16 Feb 2021

Internal wave energy in the Arctic Ocean is often an order of magnitude lower than the midlatitudes. By inhibiting energy input and causing damping, the presence of sea ice is believed to be responsible for low internal wave energy. While a few current studies have shown slightly elevated internal wave energy compared to historical measurements, it has not matched the catastrophic decline in sea ice extent over the same period. We report internal wave energy and mixing estimates that show little difference in the presence of sea ice. To examine possible causes other than sea ice, we adopt the model framework developed in Gill (1984) to explore the importance of previously unexamined factors responsible for the low internal wave energy in the Arctic Ocean. Model results show that low β and shallow mixed layers can result in significant reductions in horizontal kinetic energy in the pycnocline compared to midlatitudes.

Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean

Polyakov, I.V., and 15 others including M.B. Alkire, J. Guthrie, and J. Morison, "Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean," Science, doi: 10.1126/science.aai8204, 2017.

More Info

6 Apr 2017

Arctic sea-ice loss is a leading indicator of climate change and can be attributed, in large part, to atmospheric forcing. Here, we show that recent ice reductions, weakening of the halocline, and shoaling of intermediate-depth Atlantic Water layer in the eastern Eurasian Basin have increased winter ventilation in the ocean interior, making this region structurally similar to that of the western Eurasian Basin. The associated enhanced release of oceanic heat has reduced winter sea-ice formation at a rate now comparable to losses from atmospheric thermodynamic forcing, thus explaining the recent reduction in sea-ice cover in the eastern Eurasian Basin. This encroaching “atlantification” of the Eurasian Basin represents an essential step toward a new Arctic climate state, with a substantially greater role for Atlantic inflows.

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