[MITgcm-support] MITgcm-support Digest, Vol 94, Issue 4

Wang, Zhaomin zwa at bas.ac.uk
Tue Apr 12 03:02:54 EDT 2011 

Dear Martin and Dimitris,

Many thanks for your very helpful suggestions. We now got a right result.

Best wishes,
Zhaomin

-----Original Message-----
From: mitgcm-support-request at mitgcm.org [mailto:mitgcm-support-request at mitgcm.org] 
Sent: 06 April 2011 10:29
To: mitgcm-support at mitgcm.org
Subject: MITgcm-support Digest, Vol 94, Issue 4

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Today's Topics:

   1. Re: cube sphere 510 initial conditions
      (Menemenlis, Dimitris (3248))
   2. Re: cube sphere 510 initial conditions (Wang, Zhaomin)
   3. Re: cube sphere 510 initial conditions (Martin Losch)


----------------------------------------------------------------------

Message: 1
Date: Tue, 5 Apr 2011 17:32:58 -0700
From: "Menemenlis, Dimitris (3248)" <Dimitris.Menemenlis at jpl.nasa.gov>
To: "mitgcm-support at mitgcm.org" <mitgcm-support at mitgcm.org>
Cc: Zhaomin Wang <zwa at bas.ac.uk>, "Zhang,	Hong \(3248-Affiliate\)"
	<hong.zhang at ucla.edu>,	Jean-Baptiste Sallee <jbsallee at gmail.com>
Subject: Re: [MITgcm-support] cube sphere 510 initial conditions
Message-ID: <A9893491-6B7F-4452-869E-4D5977752FFF at jpl.nasa.gov>
Content-Type: text/plain; charset="us-ascii"

Zhaomin, UVEL is not eastward velocity, it is referenced relative to the grid, in the case of the ACC relative to the face 6 or the Antarctic face of the cube.  Did you rotate the velocity prior to generating your figures?



Dimitris Menemenlis
cell: 818-625-6498

On Apr 5, 2011, at 7:19 AM, Wang, Zhaomin wrote:

> Hi,
> 
> We are setting up a cube sphere 510 run at British Antarctic Survey. We downloaded initial conditions and forcing files from http://ecco2.jpl.nasa.gov/data1/cube/run_template/. We thought that the initial conditions were obtained from some spin-up runs. However, we noticed that UVEL does not look right in the ACC, say, there is a reasonable eastward transport between the Antarctic and the South Africa, but a large westward transport between the Antarctic and Australia. We would like to know where we can find proper initial conditions that are the results of a spin-up run and forcing files for cs510 case.
> 
> Many thanks.
> 
> Zhaomin
> British Antarctic Survey
> High Cross, Madingley Road
> Cambridge, CB3 0ET
> UK
> Tel: +44(0)1223221488
> Fax: +44(0)1223221279




------------------------------

Message: 2
Date: Wed, 6 Apr 2011 09:07:49 +0100
From: "Wang, Zhaomin" <zwa at bas.ac.uk>
To: "Menemenlis, Dimitris (3248)" <Dimitris.Menemenlis at jpl.nasa.gov>,
	"mitgcm-support at mitgcm.org" <mitgcm-support at mitgcm.org>
Cc: "Zhang, Hong \(3248-Affiliate\)" <hong.zhang at ucla.edu>,
	Jean-Baptiste Sallee <jbsallee at gmail.com>
Subject: Re: [MITgcm-support] cube sphere 510 initial conditions
Message-ID:
	<42AFDDFA3288A141B63C93EE7F138E9720D4F4E642 at nerckwmb1.ad.nerc.ac.uk>
Content-Type: text/plain; charset="us-ascii"

Dimitris,

Thanks. We have re-grided UVEL from cube sphere to spherical coordinate. So, UVEL should be eastward velocity after re-griding.

Zhaomin

-----Original Message-----
From: Menemenlis, Dimitris (3248) [mailto:Dimitris.Menemenlis at jpl.nasa.gov] 
Sent: 06 April 2011 01:33
To: mitgcm-support at mitgcm.org
Cc: Zhang, Hong (3248-Affiliate); Jean-Baptiste Sallee; Wang, Zhaomin
Subject: Re: [MITgcm-support] cube sphere 510 initial conditions

Zhaomin, UVEL is not eastward velocity, it is referenced relative to the grid, in the case of the ACC relative to the face 6 or the Antarctic face of the cube.  Did you rotate the velocity prior to generating your figures?



Dimitris Menemenlis
cell: 818-625-6498

On Apr 5, 2011, at 7:19 AM, Wang, Zhaomin wrote:

> Hi,
> 
> We are setting up a cube sphere 510 run at British Antarctic Survey. We downloaded initial conditions and forcing files from http://ecco2.jpl.nasa.gov/data1/cube/run_template/. We thought that the initial conditions were obtained from some spin-up runs. However, we noticed that UVEL does not look right in the ACC, say, there is a reasonable eastward transport between the Antarctic and the South Africa, but a large westward transport between the Antarctic and Australia. We would like to know where we can find proper initial conditions that are the results of a spin-up run and forcing files for cs510 case.
> 
> Many thanks.
> 
> Zhaomin
> British Antarctic Survey
> High Cross, Madingley Road
> Cambridge, CB3 0ET
> UK
> Tel: +44(0)1223221488
> Fax: +44(0)1223221279

-- 
This message (and any attachments) is for the recipient only NERC
is subject to the Freedom of Information Act 2000 and the contents
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------------------------------

Message: 3
Date: Wed, 06 Apr 2011 11:28:21 +0200
From: Martin Losch <Martin.Losch at awi.de>
To: mitgcm-support at mitgcm.org
Subject: Re: [MITgcm-support] cube sphere 510 initial conditions
Message-ID: <B8B94F70-22B2-49CE-8015-0BA58DF264FD at awi.de>
Content-Type: text/plain; charset="us-ascii"

Hi Zhaomin,

I use the initial conditions of the cs510 without any problems. Just regridding to lat/lon for plotting is not enough, you also need to change the orientation (for the physicists among us: a vector transforms differently from a scalar!, so you cannot treat u or v like theta, see also my previous email to you <http://mitgcm.org/pipermail/mitgcm-support/2011-April/007071.html>). When you read and plot them like this (matlab):

% use whatever way u use to read the inital conditions
u=rdmds('UVEL',0);
v=rdmds('VVEL',0);
j=1:510; i=j+5*510;
% surface velocities on the southern face
u=u(i,j,1);
v=v(i,j,1);
% rough averaging to c-points (does not work along the edges of the of the face):
uc = .5*(u+u([2:end 1],:));
vc = .5*(v+v([2:end 1],:));
% grid orientation (cos and sin of grid north relative to geographical north)
cs = rdmds('AngleCS');
sn = rdmds('AngleSN');
%
sh   =subplot(221); pcol(sq(uc)'); title('u grid')
sh(2)=subplot(222); pcol(sq(vc)'); title('v grid')
sh(3)=subplot(223); pcol(sq(uc.*cs(i,j)-vc.*sn(i,j))'); title('zonal velocity')
sh(4)=subplot(224); pcol(sq(uc.*sn(i,j)+vc.*cs(i,j))'); title('meridional velocitiy')
axis(sh,'image')
set(sh,'clim',[-1 1]*.5)

You'll see the difference. I am attaching my results of this, the zonal velocity is mostly positive in the ACC, but the u-grid velocitiy is not.

Martin

On Apr 6, 2011, at 10:07 AM, Wang, Zhaomin wrote:

> Dimitris,
> 
> Thanks. We have re-grided UVEL from cube sphere to spherical coordinate. So, UVEL should be eastward velocity after re-griding.
> 
> Zhaomin
> 
> -----Original Message-----
> From: Menemenlis, Dimitris (3248) [mailto:Dimitris.Menemenlis at jpl.nasa.gov] 
> Sent: 06 April 2011 01:33
> To: mitgcm-support at mitgcm.org
> Cc: Zhang, Hong (3248-Affiliate); Jean-Baptiste Sallee; Wang, Zhaomin
> Subject: Re: [MITgcm-support] cube sphere 510 initial conditions
> 
> Zhaomin, UVEL is not eastward velocity, it is referenced relative to the grid, in the case of the ACC relative to the face 6 or the Antarctic face of the cube.  Did you rotate the velocity prior to generating your figures?
> 
> 
> 
> Dimitris Menemenlis
> cell: 818-625-6498
> 
> On Apr 5, 2011, at 7:19 AM, Wang, Zhaomin wrote:
> 
>> Hi,
>> 
>> We are setting up a cube sphere 510 run at British Antarctic Survey. We downloaded initial conditions and forcing files from http://ecco2.jpl.nasa.gov/data1/cube/run_template/. We thought that the initial conditions were obtained from some spin-up runs. However, we noticed that UVEL does not look right in the ACC, say, there is a reasonable eastward transport between the Antarctic and the South Africa, but a large westward transport between the Antarctic and Australia. We would like to know where we can find proper initial conditions that are the results of a spin-up run and forcing files for cs510 case.
>> 
>> Many thanks.
>> 
>> Zhaomin
>> British Antarctic Survey
>> High Cross, Madingley Road
>> Cambridge, CB3 0ET
>> UK
>> Tel: +44(0)1223221488
>> Fax: +44(0)1223221279
> 
> -- 
> This message (and any attachments) is for the recipient only NERC
> is subject to the Freedom of Information Act 2000 and the contents
> of this email and any reply you make may be disclosed by NERC unless
> it is exempt from release under the Act. Any material supplied to
> NERC may be stored in an electronic records management system.
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