The transport and dynamics of wave- driven reef jets under the - - PowerPoint PPT Presentation

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The transport and dynamics of wave- driven reef jets under the - - PowerPoint PPT Presentation

Oct 11, 2022 165 likes •431 views

The transport and dynamics of wave- driven reef jets under the influence of rotation and stratification -Walter Torres Ph.D Candidate (Year III)| Duke University Advisor: Jim Hench I use Blue Waters to model circulation in the coastal

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The transport and dynamics of wave- driven reef jets under the influence

  • f rotation and stratification
  • Walter Torres

Ph.D Candidate (Year III)| Duke University Advisor: Jim Hench

“I use Blue Waters to model circulation in the coastal ocean”

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The transport and dynamics of wave- driven reef jets under the influence

  • f rotation and stratification
  • Walter Torres

Ph.D Candidate (Year III)| Duke University Advisor: Jim Hench

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The transport and dynamics of wave- driven reef jets under the influence

  • f rotation and bottom friction
  • Walter Torres

Ph.D Candidate (Year III)| Duke University Advisor: Jim Hench

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Gove, J. M. et al. Near-island biological hotspots in barren ocean basins. Nat. Commun. (2016)

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Gove, J. M. et al. Near-island biological hotspots in barren ocean basins. Nat. Commun. (2016)

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Talley and Co. 1851 General Atlas

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Talley and Co. 1851 General Atlas

Mo’orea, French Polynesia

1 km

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1 km

Mo’orea, French Polynesia

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Mo’orea, French Polynesia

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Question: What is the effect of rotation and bottom friction on the behavior of wave-driven reef jets?

Hypothesis: At given latitude, simulations with higher bottom roughness will experience attenuated waves and currents. This will produce weaker jets that are more affected by the Coriolis force and will deflect more prominently

Methods: Idealized coupled wave-circulation numerical modeling (COAWST) - suite of runs varying latitude (Φ) and bottom friction (via z0)

𝑆𝑝 = 𝑉% 𝑀 𝑔𝑉 = 𝑜𝑝𝑜𝑚𝑗𝑜𝑓𝑏𝑠 𝑑𝑝𝑠𝑗𝑝𝑚𝑗𝑡

Bottom Friction Wave+Current Magnitude Jet deflection via Coriolis

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Annulus Domain

Wave BC’s Height = 1m Period = 10s Direction = Radial-inward Δx, Δy 5m-150m vertical levels 20 Nθ, Nr 2048, 256 dt 0.5 s Parameter Values Latitude: Φ 0°, 5°,10°,15°, 20°, 25°, 30° Roughness: z0 (m) 0.001, 0.01, 0.1

Proposed runs Grid configuration

  • High resolution required resolve fine-

scale processes = short time step (must satisfy CFL) requires HPC. Thank you Blue Waters!

Challenges

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Annulus Domain

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φ = 0°

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φ = 45° φ = 45°

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φ = 45° φ = 0°

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High Friction 0º Coriolis

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Low Friction 0º Coriolis

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High Friction 30ºS Coriolis

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Low Friction 30ºS Coriolis

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Summary

  • Interaction of eddy shedding from jets, Coriolis, and stokes drift from waves

as possible retention mechanism, which is modulated by frictional processes in the back reef

Retention?

Stokes drift

Eddies

Bottom Friction Wave+Current Magnitude Jet deflection via Coriolis

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Future Work

  • Longer model integration times to allow for recirculation and eddy

interaction with other jets

  • Preferential sign of vorticity due to centrifugal instability
  • More model runs to span (z0,φ) parameter space
  • Next project: include stratification and diurnal heating forcing for more

realistic conditions capturing combined plume+jet dynamics

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φ = 45° φ = 0°

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“Winterfell”, Game of Thrones S08E01 Dave Hill et al., HBO (2019)