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<div>On Jun 29, 2024, at 4:13 PM, Wang, Ou (US 329B) <ou.wang@jpl.nasa.gov> wrote:</div>
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<div style="margin: 0in; font-size: 10pt; font-family: Aptos, sans-serif;"><span style="font-size: 11pt;">Hi Xinfeng,<o:p></o:p></span></div>
<div style="margin: 0in; font-size: 10pt; font-family: Aptos, sans-serif;"><span style="font-size: 11pt;"><o:p> </o:p></span></div>
<div style="margin: 0in; font-size: 10pt; font-family: Aptos, sans-serif;"><span style="font-size: 11pt;">In terms of z* and the real freshwater flux boundary condition, there is no change between v4r1 and v4r4. The smaller horizontal integral of the Eulerian
vertical velocity We (i.e. WVELMASS) in Figure 6 of your paper is probably because you were looking at the time-mean value. I did a quick calculation of the horizontal integrals of WVELMASS for v4r1. The time-mean value is only a few percent of Sv's, one to
two orders of magnitude smaller than that for a particular month.<o:p></o:p></span></div>
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Here is an earlier discussion of WVEL with Carl.</div>
<div>Hope it helps for this theme of discussion.</div>
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<div class="gmail_default" style="font-family: "courier new", monospace;">An interesting question, but your result and description is exactly what one would expect if I've</div>
<div class="gmail_default" style="font-family: "courier new", monospace;">understood you.</div>
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<div class="gmail_default" style="font-family: "courier new", monospace;">Even the twenty year average wvel is noisy (see the Liang etal attachment) particularly at</div>
<div class="gmail_default" style="font-family: "courier new", monospace;">depth. One slightly troubling numerical problem is that w is computed (as I understand it) </div>
<div class="gmail_default" style="font-family: "courier new", monospace;">as the residual divergence of the horizontal velocity at any given time---and that's an intrinsically</div>
<div class="gmail_default" style="font-family: "courier new", monospace;">noisy method. </div>
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<div class="gmail_default" style="font-family: "courier new", monospace;">Furthermore, in theory at hourly time steps, the internal wave field is in principle present (the</div>
<div class="gmail_default" style="font-family: "courier new", monospace;">spatial resolution of 1 degree means that it wouldn't be realistic, but the physics should apply). That</div>
<div class="gmail_default" style="font-family: "courier new", monospace;">field, and see some of the ECCO high resolution results in the other attachment) is known to be almost fully stochastic (tides</div>
<div class="gmail_default" style="font-family: "courier new", monospace;">aside) and is described by a frequency/wavenumber spectrum (Garrett-Munk). An then at low latitudes,</div>
<div class="gmail_default" style="font-family: "courier new", monospace;">the 1 degree resolution is probably sufficient to produce an eddy-like field, which is also stochastic.</div>
<div class="gmail_default" style="font-family: "courier new", monospace;">An interesting question would be what would w look like if you could average for 50 or 500 years?</div>
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<div class="gmail_default" style="font-family: "courier new", monospace;">Carl</div>
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Hi Carl,<br>
A quick question about Eulerian vertical velocity.<br>
Normally we look at monthly/yearly/decadal mean WVEL<br>
(like fig 18 in your BAMS paper for 20-yr mean WVEL).<br>
But when we look at the hourly or daily mean,<br>
it's surprised that WVEL field looks "messy" (or "grid noisy")<br>
and larger by order of magnitude,<br>
So WVEL must vary rapidly with time and place<br>
and only after much cancellation does it look "normal" (as classical <br>
gyre and upwelling).<br>
Have you touched upon this phenomenon in your papers?<br>
Or are you aware where it is discussed in the literature?<br>
<br>
cheers<br>
Hong<br>
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