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Peter Gaube

Senior Oceanographer

Email

pgaube@apl.washington.edu

Phone

206-616-0611

Education

B.A. Ecology and Evolutionary Biology, University of Arizona, 2003

M.S. Physical Oceanography, Nova Southeastern University, 2007

Ph.D. Oceanography, Oregon State University, 2012

Peter Gaube's Website

http://gaubelab.org

Publications

2000-present and while at APL-UW

Mesoscale eddies modulate mixed layer depth globally

Gaube, P., D.J. McGillicuddy Jr., and A.J. Moulin, "Mesoscale eddies modulate mixed layer depth globally," Geophys. Res. Lett., EOR, doi:10.1029/2018GL080006, 2018.

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6 Dec 2018

Mesoscale eddies, energetic vortices covering nearly a third of the ocean surface at any one time, modulate the spatial and temporal evolution of the mixed layer. We present a global analysis of concurrent satellite observations of mesoscale eddies with hydrographic profiles by autonomous Argo floats, revealing rich geographic and seasonal variability in the influence of eddies on mixed layer depth. Anticyclones deepen the mixed layer depth, whereas cyclones thin it, with the magnitude of these eddy‐induced mixed layer depth anomalies being largest in winter. Eddy‐centric composite averages reveal that the largest anomalies occur at the eddy center and decrease with distance from the center. Furthermore, the extent to which eddies modulate mixed layer depth is linearly related to the sea surface height amplitude of the eddies. Finally, large eddy‐mediated mixed layer depth anomalies are more common in anticyclones when compared to cyclones. We present candidate mechanisms for this observed asymmetry.

The unusual surface chlorophyll signatures of Southern Ocean eddies

Dawson, H.R.S., P.G. Stratton, and P. Gaube, "The unusual surface chlorophyll signatures of Southern Ocean eddies," J. Geophys. Res., 123, 6053-6069, doi:10.1029/2017JC013628, 2018.

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1 Sep 2018

Southern Ocean mesoscale eddies play an important role in ocean circulation and biogeochemical cycling, but their biological characteristics have not been well quantified at the basin scale. To address this, we combined a 15‐year tracked eddy data set with satellite observations of ocean color, sea surface temperature, and autonomous profiling floats to quantify the surface and subsurface properties of eddies. Anomalies of surface temperature and chlorophyll were examined in eddy‐centric composite averages constructed from thousands of eddies. Normalized surface chlorophyll anomalies (chlnorm) vary seasonally and geographically. Cyclones typically show positive chlnorm, while anticyclones have negative chlnorm. The sign of chlnorm reverses during late summer and autumn for eddies between the Subtropical and Polar Fronts. The reversal is most obvious in the Indian sector, and we attribute this to a combination of eddy stirring (deformation of surface gradients by the rotational velocity of an eddy) and deeper winter mixing in anticyclones. Both chlnorm and sea surface temperature anomalies transition from dipole structures north of the Subtropical Front to monopole structures south of the Subantarctic Front. Sea surface temperature and chlnorm composites provide evidence for eddy trapping (transporting of anomalies) and eddy stirring. This research provides a basin‐scale study of surface chlorophyll in Southern Ocean eddies and reveals counterintuitive biogeochemical signals.

Seasonal variation in the correlation between anomalies of sea level and chlorophyll in the Antarctic Circumpolar Current

Song, H., M.C. Long, P. Gaube, I. Frenger, J. Marshall, and D.J. McGillicuddy Jr., "Seasonal variation in the correlation between anomalies of sea level and chlorophyll in the Antarctic Circumpolar Current," Geophys. Res. Lett., 45, 5011-5019, doi:10.1029/2017GL076246, 2018.

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28 May 2018

The Antarctic Circumpolar Current has highly energetic mesoscale phenomena, but their impacts on phytoplankton biomass, productivity, and biogeochemical cycling are not understood well. We analyze satellite observations and an eddy‐rich ocean model to show that they drive chlorophyll anomalies of opposite sign in winter versus summer. In winter, deeper mixed layers in positive sea surface height (SSH) anomalies reduce light availability, leading to anomalously low chlorophyll concentrations. In summer with abundant light, however, positive SSH anomalies show elevated chlorophyll concentration due to higher iron level, and an iron budget analysis reveals that anomalously strong vertical mixing enhances iron supply to the mixed layer. Features with negative SSH anomalies exhibit the opposite tendencies: higher chlorophyll concentration in winter and lower in summer. Our results suggest that mesoscale modulation of iron supply, light availability, and vertical mixing plays an important role in causing systematic variations in primary productivity over the seasonal cycle.

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In The News

Why great white sharks hang out in warm whirlpools

National Geographic, Douglas Main

New research on famous white sharks Mary Lee and Lydia shows the giant fish spend a surprising amount of time in warm oceanic eddies.

19 Jun 2018

Great white sharks dive deep into warm-water whirlpools in the Atlantic

UW News, Hannah Hickey

A study from the University of Washington and Woods Hole Oceanographic Institution looked at the movements of adult female white sharks in the Gulf Stream and North Atlantic Ocean. Results showed, surprisingly, that they prefer warm-water eddies — the clockwise-spinning whirlpools in the ocean — and tend to spend more time deep inside these slowly spinning features.

18 Jun 2018

Sea turtles don’t just go with the flow

Physics Today, Rachel Berkowitz

Satellite data reveal that the marine reptiles change their behavior to interact with currents.

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22 Mar 2017

Using satellite transmitters attached to juvenile turtles, Peter Gaube at the University of Washington and colleagues have found that loggerhead sea turtles (Caretta caretta) modify their behavior to position themselves inside eddies. The data showed that turtles avoided the peripheries of anticyclonic eddies.Gaube proposes that the turtles were seeking the gelatinous gastropods that favor the anomalously low chlorophyll concentrations and warm water in the interior.

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Inventions

Continuous Underway Multi-sensor Profiler

Record of Invention Number: 48207

Peter Gaube, Kyla Drushka

Disclosure

15 Nov 2017

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
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