Using Okubo-Weiss Parameterization to Analyze Arctic Eddies Neesha - - PowerPoint PPT Presentation

Using Okubo-Weiss Parameterization to Analyze Arctic Eddies

Neesha Schnepf

Cornell University, GCEP SURE research fellow

Samantha Oestreicher

• Univ. of Minnesota, LANL

Beth Wingate, Matthew Hecht, Mark Peterson

LANL

Thank you!

Todd Ringler, LANL Mathew Maltrude, LANL Xylar Asay-Davis, LANL Samantha Oestreicher (Univ. of Minnesota), Beth Wingate, Matthew Hecht, Mark Peterson, LANL Jeff Gaffney, Nancy Marley, Milton Constantin, Rose-Etta Cox, GCEP

General info. on ocean eddies

• transport heat
• mix the ocean
• Nut rient s
• S

alinit y

• kinetic energy

(Stevens Institute of Technology)

General info. on ocean eddies

 mesoscale ocean

eddies:  T > t idal &

inert ial T

 unlike

atmospheric eddies:  great er durat ion  smaller scale  slower

(Stevens Institute of Technology)

(Jack Cook, Woods Hole Oceanographic Institution)

(Proshutinsky et al, 2009)

(Hunkins, 1974)

(Manley, Hunkins, 1985)

Data

 Communit y Climat e S

yst em Model 4 (CCS M4)  IPCC reports

 Parallel Ocean Program (POP)

 Resolution: .1 degree or 7-10 km

Identifying eddies

• sea surface height
• velocity and streamfunction
• vorticity
• Okubo-Weiss parameter

(S am Oestreicher)

Velocity

 v u v v v w

The x direction The y direction The z direction

 v u  v v  v w

• EW, v & NS, u: reverse sign,

magnitude increases away from center

• u & v have same rotation sense
• local velocity min at center

(Nencioli, Dong, Dickey, Washburn, McWilliams, 2009)

(Nencioli, Dong, Dickey, Washburn, McWilliams, 2009)

(Nencioli, et al, 2010)

Vorticity

 Tendency t o swirl  >0 is clockwise  <0 is count er clockwise

 ∇ = d dx , d dy , d dz       v v = (u,v,w) v ω = r ∇ × v v = i j k d dx d dy d dz u v w = dw dy − dv dz , du dz − dw dx , dv dx − du dy      

Okubo-Weiss Parameter

(Sean Williams)

(Sean Williams)

(Sean Williams)

(Sean Williams)

(afsc.noaa.gov)