<div dir="ltr">Hi All,<div><br></div><div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div>Is it possible that this issue depends on the version of ECCO? I did a similar calculation a long time ago with ECCO v4r1, and the horizontal integrals of We and Wb were both zero (almost). Check out Figure 6 of this paper <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JC012985">https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JC012985</a>. Has anything changed since then that could affect this?<br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div dir="auto" style="font-family:Helvetica;color:rgb(0,0,0)"><br></div><div dir="auto" style="font-family:Helvetica;color:rgb(0,0,0)">Best,<br>Xinfeng<br>---------------------------<br>Xinfeng Liang<br>Associate Professor</div><div dir="auto" style="font-family:Helvetica;color:rgb(0,0,0)">School of Marine Science and Policy<br>University of Delaware<br> <br>700 Pilottown Road<br>Lewes, DE 19958<br>302-645-4036<br><a href="mailto:xfliang@udel.edu" target="_blank">xfliang@udel.edu</a></div><div dir="auto" style="color:rgb(0,0,0);font-family:Helvetica"><a href="https://sites.udel.edu/xfliang/" target="_blank">https://sites.udel.edu/xfliang/</a></div></div></div></div></div></div></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jun 28, 2024 at 12:00 PM <<a href="mailto:ecco-support-request@mit.edu">ecco-support-request@mit.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Send ecco-support mailing list submissions to<br>
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1. Re: Global integral of vertical momentum flux not zero?<br>
(Jean-Michel Campin)<br>
<br>
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Message: 1<br>
Date: Fri, 28 Jun 2024 11:44:40 -0400<br>
From: Jean-Michel Campin <<a href="mailto:jmc@mit.edu" target="_blank">jmc@mit.edu</a>><br>
To: "ECCO support list, wider membership" <<a href="mailto:ecco-support@mit.edu" target="_blank">ecco-support@mit.edu</a>><br>
Subject: Re: [ecco-support] Global integral of vertical momentum flux<br>
not zero?<br>
Message-ID: <<a href="mailto:20240628154440.GA20988@ocean.mit.edu" target="_blank">20240628154440.GA20988@ocean.mit.edu</a>><br>
Content-Type: text/plain; charset=us-ascii<br>
<br>
Hi Paola and Fabien,<br>
<br>
Ou is right, the horizontal integral of wVel is not zero because of z*.<br>
With z*, wVel(k) (which corresponf to (H+Eta)/H*w* in the 2004 paper eq 11) is computed<br>
by integrating eq.11 from bottom to level k, <br>
but because the depth H is not uniform everywhere (not a flat bottom)<br>
this second contribution is not zero when integrated vertically to interface k, and this<br>
is the case even if the global integral of d.Eta/dt was zero (which I am not sure it is,<br>
with frrsh water input and seaice, but it's an other story).<br>
<br>
Cheers,<br>
Jean-Michel<br>
<br>
On Fri, Jun 28, 2024 at 03:07:53PM +0000, Menemenlis, Dimitris (US 329B) wrote:<br>
> Paola, Ou, and Fabien, I wonder if non-zero Evaporation minus Precipitation minus Runoff (EmPmR), including freshwater exchange with sea ice, could be the cause of non-zero WVELMASS in a ???realfreshwaterflux??? MITgcm configuration?<br>
> <br>
> But these realfreshwaterflux volume fluxes could probably not explain ???order several Sv??? of horizontal integral of w. Back of the envelope, a 2-cm sea level seasonal cycle of land-to-ocean mass transfer is a ~0.2 Sv vertical velocity at surface. The Greenland and Antarctic mass loss is of order ~0.01 Sv at the surface. The seasonal cycle of freshwater exchange with sea ice is ~1 Sv around Antarctica and 0.5 Sv in Arctic. Subsurface WVELMASS would be proportionately smaller in z* coordinates.<br>
> <br>
> Dimitris<br>
> <br>
> <br>
> On Jun 28, 2024, at 1:51???AM, Paola Cessi <<a href="mailto:pcessi@ucsd.edu" target="_blank">pcessi@ucsd.edu</a>> wrote:<br>
> <br>
> Hi Ou,<br>
> <br>
> could you please elaborate of why this is the case? When I look at Adcroft & Campin 2004 (A&C04), even in z* coordinates WVELMASS should have zero horizontal integral. If you look at eq 11 of A&C04, the continuity eqn has an extra term (independent of z) given by \eta_t, but I believe it also has zero area average, when you compare it to (12) in A&C04, because the area integral of E-P is also made to be zero in ECCO. Unless there is something to do with the ice, which is not covered in A&C04, I don???t see why <w> is not zero.<br>
> <br>
> Can you please enlighten us?<br>
> <br>
> Many thanks,<br>
> Paola<br>
> <br>
> On Jun 27, 2024, at 2:17???AM, Wang, Ou (US 329B) <<a href="mailto:ou.wang@jpl.nasa.gov" target="_blank">ou.wang@jpl.nasa.gov</a>> wrote:<br>
> <br>
> Hello Fabien,<br>
> <br>
> You haven???t missed anything in your calculation. The horizontal integral of area-weighted vertical velocity (WVELMASS) across a particular vertical level does not necessarily equal zero.<br>
> <br>
> Best regards,<br>
> Ou Wang<br>
> <br>
> From: ecco-support <<a href="mailto:ecco-support-bounces@mit.edu" target="_blank">ecco-support-bounces@mit.edu</a><mailto:<a href="mailto:ecco-support-bounces@mit.edu" target="_blank">ecco-support-bounces@mit.edu</a>>> on behalf of Fabien Roquet <<a href="mailto:fabien.roquet@gu.se" target="_blank">fabien.roquet@gu.se</a><mailto:<a href="mailto:fabien.roquet@gu.se" target="_blank">fabien.roquet@gu.se</a>>><br>
> Date: Monday, June 24, 2024 at 1:15???PM<br>
> To: <a href="mailto:ecco-support@mit.edu" target="_blank">ecco-support@mit.edu</a><mailto:<a href="mailto:ecco-support@mit.edu" target="_blank">ecco-support@mit.edu</a>> <<a href="mailto:ecco-support@mit.edu" target="_blank">ecco-support@mit.edu</a><mailto:<a href="mailto:ecco-support@mit.edu" target="_blank">ecco-support@mit.edu</a>>><br>
> Subject: [EXTERNAL] [ecco-support] Global integral of vertical momentum flux not zero?<br>
> Hello ECCO team,<br>
> I have downloaded ECCO from PO.DAAC.<br>
> Using WVELMASS from ECCO_L4_OCEAN_3D_VOLUME_FLUX_LLC0090GRID_DAILY_V4R4, multiplying with rA and summing along i, j, and tiles, I find the horizontal integral of w is not zero. Am I missing something?<br>
> See picture for the vertical profile of w, which is of order several Sv.<br>
> Thanks for your help,<br>
> Fabien<br>
> <br>
> <br>
<br>
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