Lower Cell - PowerPoint PPT Presentation

Lower cell
1 / 17

  • Uploaded on
  • Presentation posted in: General

Lower Cell. What is it What makes it What’s missing. Here it is. Deacon, Sverdrup Wyrtki added wind-driven numbers ~2Sv Callahan, Mollinelli, Warren. Sverdrup, Johnson & Fleming (1942). The view from Antarctica. Oxygen. Salinity. Orsi. Global box inverse model (Lumpkin).

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Presentation

Lower Cell

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Lower cell

Lower Cell

What is it

What makes it

What’s missing

Here it is

Here it is

Deacon, Sverdrup

Wyrtki added wind-driven numbers ~2Sv

Callahan, Mollinelli, Warren

Sverdrup, Johnson & Fleming (1942).

Lower cell

The view from Antarctica




Global box inverse model lumpkin

Global box inverse model (Lumpkin)

Trop. Pac. box

S.Ocn. (Pac) box

S.Atl. box


Wed. box

Ross box

S.Ocn. (Atl) box

Med. box

Arctic/GIN box

Outer Wed. box

Trop. Pac. box

Pac. Subpolar box

Pac. Subtropical box

overflow box

Atl. Subpolar box

Amery box

Atl. Subtropical box

Atl. Eq. box

S.Ocn. (Ind) box

Ind. box



Observations (WBCs, choke point transports, air-sea fluxes, …)

Parameterizations (diapycnal fluxes, eddy transports, …)

But are they consistent?

An initial approach: various air-sea flux climatologies.

Lower cell







S4 composite



Northern southern hemisphere forcing

Northern/Southern hemisphere forcing


Atlantic ocean overturning cell

Atlantic Ocean overturning cell

Atlantic ocean overturning cell1

Atlantic Ocean overturning cell

Overflow vs Irm/Lab

Overturning across 32ºS:

13.1  1.9 Sv upper

-18.9  2.7 Sv NADW

5.6  2.0 Sv AABW

Saunders&King (1995): -22 Sv NADW

Macdonald (1998): -20 Sv NADW

Ganachaud (1999): -23 Sv NADW

Sloyan&Rintoul (2001): -18 Sv NADW

Northward transport, mode-to-intermediate

densities (26.0<n<27.4):

11 ± 2 Sv (ECMWF) to 13±2 Sv (NCEP)

[8 ± 2 Sv (SOC unadj.)]

Sloyan and Rintoul (2001): 16 Sv.

Karstensen and Quadfasel (2003): 14 Sv ventilation

Three oceans moc


Three Oceans MOC


Southern Ocean


(Ganachaud 48N

28.1 ref level)

Not same solution as published but similar…

Pac ind overturning


Indian: 9.0  2.8 Sv

Toole&Warren (1993): 25 Sv

Robbins&Toole (1997): 12 Sv

Ganachaud (1999): 11 Sv

Sloyan&Rintoul (2001): 23 Sv

Bryden&Beal (2001): 10 Sv

Pacific: 14.2  3.2 Sv

Ganachaud (1999): 10 Sv

Sloyan&Rintoul (2001): 26 Sv

Wijffels et al. (2001): 16-20 Sv

Pac, Ind overturning

Indian Ocean



12.42.1 Sv

Pacific Ocean

Controls on strength

Controls on strength

Wind versus buoyancy


~ half subpolar gyre convection and half overflow

Var of AMOC ~ var of wind

Var of overflow ~ weak?

Southern Ocean

Coastal polynyas

Occasional open ocean polynyas

Overflow plumes and entrainment

Mixing over topography (IWs and sills)

Consider coastal polynyas…

Realistic outflow adjusted fluxes and polynyas

S4 (62ºS)

Heat gain in layer (PW)

Realistic outflow: adjusted fluxes and polynyas

unadjusted ECMWF


Coastal Polynyas

Adjusted – unadjusted ECMWF (W/m2)

Bottom water formation in the antarctic boxes

Bottom water formation in the Antarctic boxes



Unconstrained solution

Solution consistent with CFC measurements

(Orsi, Smethie & Bullister, 2002)



Zonal streamfunction with topo

Zonal Streamfunction with Topo

Lower cell

3D Streampath

Deep upwelling

Isopycnal upwelling

Convection region

Lower cell what s missing

Lower Cell – what’s missing?

Deep diapycnal flux

Cross – ACC pathways

Entrainment (plumes and ridges)

Bottom water evolution

Control by wind and buoyancy flux

Atlantic cell on s and o2

Atlantic Cell on S and O2

  • Login