# No subject

Fri Nov 30 02:28:46 EST 2012

```My simulation have been run with rigid-lid , frequency for the diagnostics =
432000 s , step of integration equal to 1200s , flux momentum formulation, =
24 levels , 17 x 49 points for each levels, hydrostatic configuration.

So following previous post the balance of momentum should be given for each=

But :

a) I saw from MITGCM manual that Um_Advec includes all the terms of acceler=
ation including Coriolis, explicit diffusive terms , metric and pressure te=
_Cori+Um_diss+Um_ext+Um_HydroP?

b) I have the rigid  -lid and so I should include in  the balance also the =
term relative to Eta . How can I compute the contribution of Eta ? Is it si=
mply dEta/dx =3D [Eta(i+1,j)-Eta(i,j)]/dxc(i,j)?or Should I consider to mul=
tiply this term for something else?In fact Eta with rigid lid is a pressure=
and so not an acceleration.Then It=92s given on a single level: so should =
I sum this quantity to each level or dividing/multiplying it for something =
and then add to each level?

Finally I considered a point in my domain in the first level and in the cen=
ter of my domain at the time t=3D1 and I did the balance : TOTUtend/86400=

TOTUtend/86400=3D-1.02*10^-9

The signs coincide : the values appears to be different..what looks strange=
to me is also the sign because Uvel is positive.Did I something wrong in t=
he computation? Did I forget some terms?Is it correct TOTUtend/86400?

Looking forward to a positive response to my question

Best regards

Marco

***********************************
Marco Reale
ph.D student "Environmental and Industrial Fluid Mechanics"-XXVII cycle
University of Trieste-Department of Mathematics and Informatics
National Institute of Geophysics and Oceanography (OGS)
International Center for Theorethical Physics (ICTP)
Italian Geophysical Association (AGI)
Italian Meteorological Society (SMI)
European Geophysical Union (EGU)
web-page: http://phdfluidmechanics.appspot.com/stud.html?Reale
skype: mcreal82
phone number: +39 3270888069

***********************************

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MITgcm-support at mitgcm.org<mailto:MITgcm-support at mitgcm.org>
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***************************************************************************=
**

Dr. David R. Munday
University of Oxford
Atmospheric, Oceanic, and Planetary Physics
Clarendon Laboratory
Oxford
OX1 3PU
U.K.                 01865 282 439

***************************************************************************=
**

"But I, being poor, have only my dreams;
- W.B. Yeats, He Wishes for the Cloths of Heaven -

***************************************************************************=
**

--_000_7B3679F5F43F4FDD96DB60D6127BC746atmoxacuk_
Content-Type: text/html; charset="Windows-1252"
Content-ID: <DC48463F3F8A834F858CB1F5F483A720 at physics.ox.ac.uk>
Content-Transfer-Encoding: quoted-printable

<html>
<meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3DWindows-1=
252">
<body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-lin=
e-break: after-white-space; ">
Hi Marco,
<div><br>
</div>
<div>
<blockquote type=3D"cite">
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space; ">
<div>a) I saw from MITGCM manual that Um_Advec includes all the terms of ac=
celeration including Coriolis, explicit diffusive terms , metric and pressu=
ec&#43;Um_Cori&#43;Um_diss&#43;Um_ext&#43;Um_HydroP?</div>
</div>
</blockquote>
</div>
<div>
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space; ">
<div><br>
</div>
</div>
</div>
<div>Um_Advec includes Um_Cori, and any metric terms if you're using flux-f=
orm I guess. Um_diss, etc, aren't in Um_Advec and so you need to include th=
<div><br>
</div>
<div>As far as I'm aware, any explicit viscosity terms are also in Um_diss.=
I use implicit vertical viscosity, though, so I've never checked.</div>
<div><br>
</div>
<div>
<blockquote type=3D"cite">
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space; ">
<div>b) I have the rigid &nbsp;-lid and so I should include in &nbsp;the ba=
lance also the term relative to Eta . How can I compute the contribution of=
Eta ? Is it simply dEta/dx =3D [Eta(i&#43;1,j)-Eta(i,j)]/dxc(i,j)?or Shoul=
d I consider to multiply this term for something
else?In fact Eta with rigid lid is a pressure and so not an acceleration.T=
hen It=92s given on a single level: so should I sum this quantity to each l=
evel or dividing/multiplying it for something and then add to each level?</=
div>
</div>
</blockquote>
<div><br>
</div>
<div>Are you actually using a rigid lid? Or a linear free surface? Its only=
if you're using a linear free surface that I think you need to worry about=
this.</div>
<div><br>
</div>
I output the horizontal gradients of eta, really the gradient in surface po=
tential, from momentum_correction_step.F. The quantities you need are calcu=
lated here and then used to update the U and V velocities. Just output phis=
urfX and phisurfY multiplied by
-1 to get the sign right. They're 2D fields, but the same value applies at=
every vertical model level.</div>
<div><br>
</div>
<div>Once you've got these gradients you should get an extremely well close=
d momentum budget by following the recipe in the chain of e-mails starting =
with Emily Shroyer's from December 2010, see
html#6918">
a>. These e-mails saved me a whole load of time when I wanted to close the =
momentum budget (thanks Emily, Matt, and Jean-Michel!)</div>
<div><br>
</div>
<div>
<blockquote type=3D"cite">
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space; ">
<div>The signs coincide : the values appears to be different..what looks st=
range to me is also the sign because Uvel is positive.Did I something wrong=
in the computation? Did I forget some terms?Is it correct TOTUtend/86400?<=
/div>
</div>
</blockquote>
</div>
<div>
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space; ">
<div><br>
</div>
<div>The sign of the tendency, total or otherwise, won't tell you the sign =
of U, just the sign of its change. See the e-mails linked above for what to=
add together. Yes, TOTUTEND should be divided by 86400 to get /s.</div>
<div><br>
</div>
</div>
</div>
<div>Best wishes,</div>
<div><br>
</div>
<div>Dave<br>
<div>
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space; ">
<div><br>
</div>
</div>
</div>
<div>
<div>On 3 Dec 2013, at 23:08, Marco Reale wrote:</div>
<br class=3D"Apple-interchange-newline">
<blockquote type=3D"cite">
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space;">
Dear MITGCM users ,&nbsp;
<div><br>
</div>
<div>following the suggestion of Dr.Losch I posted a question about an anal=
ysis that I=92m doing. I=92m trying to compute a balance of vorticity for a=
basin : the first assessment (and verification) in this analysis is the co=
mputation of balance of momentum . Following
a previous post in this mailing list I got during from my simulation the f=
ollowing diagnostics (I will talk only about &nbsp;U-component):</div>
<div><br>
</div>
m using an explicit scheme).</div>
<div><br>
</div>
<div>From VISrE_Um I computed : &nbsp;Um_Expl(:,:,k) =3D[ VISrE_Um(:,:,k&#4=
3;1) - VISrE_Um(:,:,k) ]&nbsp;/[ rAw(:,:)*drF(k)*hFacW(:,:,k) ]</div>
<div><br>
</div>
<div>My simulation have been run with rigid-lid , frequency for the diagnos=
tics 432000 s , step of integration equal to 1200s , flux momentum formulat=
ion, 24 levels , 17 x 49 points for each levels, hydrostatic configuration.=
</div>
<div><br>
</div>
<div>So following previous post the balance of momentum should be given for=
#43;Um_HydroP&#43;Um_Expl</div>
<div><br>
</div>
<div>But :</div>
<div><br>
</div>
<div>a) I saw from MITGCM manual that Um_Advec includes all the terms of ac=
celeration including Coriolis, explicit diffusive terms , metric and pressu=
ec&#43;Um_Cori&#43;Um_diss&#43;Um_ext&#43;Um_HydroP?</div>
<div><br>
</div>
<div>b) I have the rigid &nbsp;-lid and so I should include in &nbsp;the ba=
lance also the term relative to Eta . How can I compute the contribution of=
Eta ? Is it simply dEta/dx =3D [Eta(i&#43;1,j)-Eta(i,j)]/dxc(i,j)?or Shoul=
d I consider to multiply this term for something
else?In fact Eta with rigid lid is a pressure and so not an acceleration.T=
hen It=92s given on a single level: so should I sum this quantity to each l=
evel or dividing/multiplying it for something and then add to each level?</=
div>
<div><br>
</div>
<div>Finally I considered a point in my domain in the first level and in th=
e center of my domain at the time t=3D1 and I did the balance : TOTUtend/86=
t&nbsp;</div>
<div><br>
</div>
<div>TOTUtend/86400=3D-1.02*10^-9</div>
^-9</div>
<div><br>
</div>
<div>The signs coincide : the values appears to be different..what looks st=
range to me is also the sign because Uvel is positive.Did I something wrong=
in the computation? Did I forget some terms?Is it correct TOTUtend/86400?<=
/div>
<div><br>
</div>
<div><br>
</div>
<div>Looking forward to a positive response to my question</div>
<div><br>
</div>
<div><br>
</div>
<div>Best regards</div>
<div><br>
</div>
<div><br>
</div>
<div>Marco</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>
<div apple-content-edited=3D"true">
<div style=3D"color: rgb(0, 0, 0); font-family: Helvetica;  font-style: nor=
mal; font-variant: normal; font-weight: normal; letter-spacing: normal; lin=
e-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; t=
ext-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -we=
bkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: spac=
e; -webkit-line-break: after-white-space;">
***********************************<br>
Marco Reale<br>
ph.D student &quot;Environmental and Industrial Fluid&nbsp;Mechanics&quot;-=
XXVII cycle<br>
University of Trieste-Department of Mathematics and&nbsp;Informatics<br>
National Institute of Geophysics and Oceanography&nbsp;(OGS)<br>
International Center for Theorethical Physics (ICTP)<br>
Italian Geophysical Association (AGI)<br>
Italian Meteorological Society (SMI)</div>
<div style=3D"color: rgb(0, 0, 0); font-family: Helvetica;  font-style: nor=
mal; font-variant: normal; font-weight: normal; letter-spacing: normal; lin=
e-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; t=
ext-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -we=
bkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: spac=
e; -webkit-line-break: after-white-space;">
European Geophysical Union (EGU)<br>
web-page:&nbsp;<a href=3D"http://phdfluidmechanics.appspot.com/stud.html?Re=
ale">http://phdfluidmechanics.appspot.com/stud.html?Reale</a><br>
skype: mcreal82<br>
phone number: &#43;39 3270888069<br>
<br>
***********************************</div>
</div>
<br>
</div>
</div>
_______________________________________________<br>
MITgcm-support mailing list<br>
<a href=3D"mailto:MITgcm-support at mitgcm.org">MITgcm-support at mitgcm.org</a><=
br>
http://mitgcm.org/mailman/listinfo/mitgcm-support<br>
</blockquote>
</div>
<br>
<div><span class=3D"Apple-style-span" style=3D"border-collapse: separate; c=
olor: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-varian=
t: normal; font-weight: normal; letter-spacing: normal; line-height: normal=
; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: n=
one; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-hori=
zontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-dec=
ke-width: 0px; font-size: medium; "><span class=3D"Apple-style-span" style=
=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica;=
font-style: normal; font-variant: normal; font-weight: normal; letter-spac=
ing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; tex=
t-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-s=
pacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertica=
l-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size=
-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; ">
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space; ">
<span class=3D"Apple-style-span" style=3D"border-collapse: separate; color:=
rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: no=
rmal; font-weight: normal; letter-spacing: normal; line-height: normal; orp=
hans: 2; text-indent: 0px; text-transform: none; white-space: normal; widow=
s: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-bo=
rder-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webk=
it-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: mediu=
m; ">
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<span class=3D"Apple-style-span" style=3D"border-collapse: separate; color:=
rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: no=
rmal; font-weight: normal; letter-spacing: normal; line-height: normal; orp=
hans: 2; text-indent: 0px; text-transform: none; white-space: normal; widow=
s: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-bo=
rder-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webk=
it-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: mediu=
m; ">
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space; ">
<span class=3D"Apple-style-span" style=3D"border-collapse: separate; color:=
rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: no=
rmal; font-weight: normal; letter-spacing: normal; line-height: normal; orp=
hans: 2; text-indent: 0px; text-transform: none; white-space: normal; widow=
s: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-bo=
rder-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webk=
it-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: mediu=
m; ">
<div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line=
-break: after-white-space; ">
<div>
<div style=3D"font-size: 14px; ">******************************************=
***********************************<br>
</div>
<div style=3D"font-size: 14px; "><br>
</div>
<div style=3D"font-size: 14px; ">Dr. David R. Munday</div>
<div style=3D"font-size: 14px; ">University of Oxford</div>
<div style=3D"font-size: 14px; ">Atmospheric, Oceanic, and Planetary Physic=
s</div>
<div style=3D"font-size: 14px; ">Clarendon Laboratory</div>
<div style=3D"font-size: 14px; ">Oxford</div>
<div style=3D"font-size: 14px; ">OX1 3PU</div>
<div style=3D"font-size: 14px; ">U.K. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &n=
bsp; &nbsp; &nbsp; 01865 282 439</div>
<div style=3D"font-size: 14px; "><br>
</div>
<div style=3D"font-size: 14px; ">******************************************=
***********************************</div>
<div style=3D"font-size: 14px; "><br>
</div>
<div style=3D"font-size: 14px; ">&quot;But I, being poor, have only my drea=
ms;</div>
div>
s.&quot;</div>
<div style=3D"font-size: 14px; ">&nbsp;&nbsp; &nbsp;&nbsp;- W.B. Yeats, He =
Wishes for the Cloths of Heaven -</div>
<div style=3D"font-size: 14px; "><br>
</div>
<div style=3D"font-size: 14px; ">******************************************=
***********************************</div>
</div>
</div>
</span></div>
</span></div>
</span></div>
</span></span></div>
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--_000_7B3679F5F43F4FDD96DB60D6127BC746atmoxacuk_--

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