Representing the Effects of Eddy Stress in the Arctic Z. Wang G Representing the Effects of Eddy Stress in the Arctic Z. Wang G. Holloway Y. Lu D. Wright Fisheries and Oceans Canada
Outline Model description Neptune --- Summary What is Neptune? impacts on Arctic circulations flows in the Canadian Arctic Archipelago transports and properties in Fram Strait Summary
Neptune - “topostress” Model Description Uses the NEMO ocean module (z-level, C-grid) and LIM2 ice module (2 ice layers, 1 snow layer) Nominally 1-deg resolution; tri-polar grid with finest resolution in Arctic/CAA; enhanced resolution in tropics Forcing: A daily climatology derived from ECWMF reanalysis; monthly river runoff Bulk formulae Neptune - “topostress” Representing effects of eddy-topography interactions Barotropic flow relaxed to a mean current in the direction of topographic Rossby wave propagation
Neptune velocity in the Arctic The barotropic velocity field that we relax towards
Impact of Neptune: Arctic Circulation at 51 m depth
Impact of Neptune: Arctic Circulation at 226 m depth
Impact of Neptune: Arctic Circulation at 531 m depth
Impact of Neptune: Arctic Circulation at 984 m depth Arctic 984m
Canadian Arctic Archipelago Circulation Having the difference plot appear on top of the Neptune plot would help to see what has changed.
Model assessment based on topostrophy, τ Current meter locations in the Arctic Friction: skill=0.37 Neptune: skill=0.79
Neptune impact on flow through Fram Strait The result without Neptune The change due to Neptune
Temperature at 79N, modelled and observed Average of the monthly means measured by a moored array in 2002-2008 AWI
Fluxes through Fram Strait Friction Neptune OBS Volume transport|(Sv) North 1.27 2.38 10 Schauer South 3.90 4.47 12 Ice volume (km3/year) 2838 2649 1530-3600 (Aagaard and Carmack 1989) Heat (TW) 17 27 24-36 Schaurer(ASOF book) Freshwater-liquid (mSv) 45 56 63.1 Lique(2009)
Ice thickness in March Neptune - Friction Friction Suggest showing Friction and Neptune first and then have Neptune-Friction appear on top of the Neptune result. Similar to slide 9.
Summary Neptune --- brings large scale Arctic circulation closer to observed produces the observed reversed flows in the CAA improves the heat and freshwater transports reduces the width of the ice tongue in the Fram Strait