[MITgcm-support] weak AMOC in LLC90

[Judith Hauck]

Dear all,

I have started to use the LLC90 set-up as provided by Gael 
(http://mitgcm.org/viewvc/MITgcm/MITgcm_contrib/gael/verification/global_oce_llc90/?hideattic=0&sortby=author) 
and noticed that the Atlantic Meridional Circulation (AMOC) is really 
weak (<10 Sv) after 100 years.

That was noticed early on in this conversation on the developer list:

http://mitgcm.org/pipermail/mitgcm-devel/2007-September/002973.html

I have used both the CORE2 and the (climatological, daily) Drakkar 
forcing with asynchronous time-step, but the Drakkar forcing doesn't 
make any difference for the AMOC.

The only paper I've found that shows published AMOC from the LLC90 
set-up is the Danabasoglu et al.: North Atlantic simulations in 
Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part I: 
Mean states, Ocean Modelling, 2014, doi:10.1016/j.ocemod.2013.10.005

In that paper, the MITgcm AMOC is also weak (but rather at 11 Sv after 
100 years). Most models in that comparison have rather weak AMOC, so is 
that something that we just have to accept when using truely global 
configurations?

I haven't yet plotted a time-series of the AMOC as in that paper with 
synchronous time-stepping, will do.

Has any one experience on what possibilities there are to get a stronger 
AMOC in the global LLC90 set-up? What works? What does not work?

I'd appreciate any feedback.

Thanks,
Judith

-- 
Judith Hauck
Alfred Wegener Institute for Polar and Marine Research
Am Handelshafen 12
27570 Bremerhaven

+49 (0)471-4831-1892
judith.hauck at awi.de

http://www.awi.de/People/show?jhauck

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