<div dir="ltr"><div>Hi Jody</div><div><br></div><div>In bling_airseaflux.F there is code for oxygen gas exchange based on the<br></div><div>Wanninkhof 1992 formula that is quadratic in windspeed (JGR, V.97, NO. C5,pp. 7373-7382, <br></div><div>updated in Wanninkhof 2014 Limnology and Oceanography:Methods, 12, pp 351-362).</div><div><br></div><div>The gas exchange velocity (kwexch) dependency on the windspeed and on the Schmidt number (Sc),</div><div>and the gas flux go like this:<br></div><div>kwexch = a * (Sc/660)^(-1/2) * windspeed^2, where Flux = kexch * [Ca - Cw]</div><div>where Ca and Cw are the oxygen concentration in the atmosphere and ocean.<br></div><div>The leading constant "a" depends on the wind product (see, e.g. Sweeney et al. 2007, Global Geochemical Cycles,</div><div>v. 21, GB2015).</div><div><br></div><div>The bling code doesn't use the same Schmidt number coefficients given in Wanninkhof 2014 (in bling_init_fixed.F)<br></div><div>and instead of using the Bunsen solubility of Wanninkhof 2014, it uses the C*_o <br></div><div>solubility from Garcia and Gordon 1992 (Limnololgy and Oceanography, 37(6), pp. 1307-1312).<br></div><div><br></div><div>The dependency on T and S is buried in the Schmidt Number, and in the solubility.</div><div>Wanninkhof 1992 gives the Schmidt number as third order polynomial in T.</div><div>Garcia and Gordon provide another polynomial/logarithmic mixed formula for the solubility as a function of T and S.<br></div><div><br></div><div>I hope this helps,</div><div>Gus Correa<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, May 22, 2022 at 4:55 AM Jody Klymak <<a href="mailto:jklymak@uvic.ca" target="_blank">jklymak@uvic.ca</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"><div dir="auto">Dear Matt and Manfredi,<div><br></div><div>Thanks to you both. I think that is more than enough to point me in the right direction. </div><div><br></div><div>Cheers Jody<br><br><div dir="ltr">Sent from my iPhone</div><div dir="ltr"><br><blockquote type="cite">On May 22, 2022, at 00:01, Manfredi Manizza <<a href="mailto:mmanizza@ucsd.edu" target="_blank">mmanizza@ucsd.edu</a>> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><div dir="ltr"><div>Hi Jody,</div><div><br></div><div>I think you could look at code of the DIC package that comes with MITgcm. You can either strip down the code to 1 tracer and </div><div>also remove the routine of gas exchange for CO2 or you can then just copy from that code the routine for gas exchange of O2 with the solubility and gas exchange parameters along that you need to make it work and re-adapt to your code.</div><div><br></div><div>In the second case you might need gchem pkg too (is needed for dic pkg too I think) compiled to make it work. Then you add the gas exchange code</div><div>and pass the flux term to your O2- like tracer tendency only if k = 1 (surface ocean only).</div><div><br></div><div>Here below something similar to your case done a while ago where I added the "thermal oxygen"</div><div>but still in the context of a full bgc model. </div><div><br></div><div>In that case I just copied the code of the oxygen cycle and removed the </div><div>"sources minus sink" term so that it becomes "abiotic" only, like that tracer you want to obtain for</div><div>your study in the fjord if I understood correcly.</div><div><br></div><div><a href="https://www.tandfonline.com/doi/full/10.3402/tellusb.v64i0.18429" target="_blank">https://www.tandfonline.com/doi/full/10.3402/tellusb.v64i0.18429</a><br></div><div><br></div><div>I hope this helps.</div><div><br></div><div>Manfredi</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, May 21, 2022 at 2:51 AM Jody Klymak <<a href="mailto:jklymak@uvic.ca" target="_blank">jklymak@uvic.ca</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">Hi all,<br>
<br>
I am trying to add a crude oxygen signal to a wind and thermally forced fjord simulation. I don’t particularly need the oxygen to interact bio-chemically with anything, but I assume it would be more realistic for the gas exchange to depend on the wind speed and the surface oxygen saturation (as a function of T and S). <br>
<br>
I am finding it a little difficult to parse how I might do that. I don’t see a surface forcing for ptracer. It seems that maybe biochem has all this, but its still not clear if I should use all this machinery and how to initialize in an idealized sense. <br>
<br>
Any pointers gratefully received. <br>
<br>
Thanks a lot. Jody<br>
<br>
--<br>
Jody Klymak <br>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><pre cols="72">Dr. Manfredi Manizza
Geosciences Research Division
Scripps Institution of Oceanography
University of California San Diego
9500 Gilman Drive La Jolla, CA 92093-0244
email : <a href="mailto:mmanizza@ucsd.edu" target="_blank">mmanizza@ucsd.edu</a>
tel : +1-858-534-7094
web : <a href="http://bluemoon.ucsd.edu/mmanizza/" target="_blank">http://bluemoon.ucsd.edu/mmanizza/</a> </pre><pre cols="72">web : <a href="https://mmanizza.scrippsprofiles.ucsd.edu/" style="font-family:Arial,Helvetica,sans-serif" target="_blank">https://mmanizza.scrippsprofiles.ucsd.edu/</a></pre></div></div></div></div></div>
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