<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Hello everyone</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I am currently using MITgcm to model the biogeochemistry in the context of paleoclimate. For the same, I have created an offline 2d model that uses the packages: dic, gchem, ptracers in conjunction with shelfice. </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I am facing a problem with the concentration of the nutrient (phosphate - PO4) in the model --- the concentration does not reach a steady-state. After just a few years of integration, the concentration deviates significantly from what it should be. In fact, the initial concentration of PO4 increases well beyond what I initially start with. </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I have gone through many threads provided in [MITgcm-support] dealing with similar problems but none of the solutions listed there worked for my problem. I have already tried the following:<br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">1. Used the model with only dissolved organic phosphorus (DOP) and PO4 --- no problem in this case. The net Phosphorus is conserved and both PO4 and DOP concentrations reach a steady-state. <span style="font-family:Arial,Helvetica,sans-serif">Somehow the parametrization for remineralization of particulate organic matter (POP) does not work well in the offline mode (</span><span class="gmail_default" style="font-family:Arial,Helvetica,sans-serif">MITgcm/</span><span style="font-family:Arial,Helvetica,sans-serif">pkg/dic/phos_flux.F</span><span style="font-family:Arial,Helvetica,sans-serif">)</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">2. Running the model without the shelfice package --- the problem persists. </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">3. Verified that the PTRACERS_EvPrRn is unset.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Please note that the online model with the same configuration works well. I'd really appreciate any help in this regard. </div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Thank you,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Regards,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Kaushal.</div></div><div><br></div>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div style="font-size:small;color:rgb(0,0,0);font-family:Helvetica;word-wrap:break-word"><div style="font-size:12.8px;letter-spacing:0.2px;word-wrap:break-word"><font size="2"><b>Kaushal Gianchandani<br></b>Ph.D. Student in Oceanography<br>Fredy & Nadine Herrmann Institute of Earth Sciences</font></div><div style="font-size:12.8px;letter-spacing:0.2px;word-wrap:break-word"><font size="2">Hebrew University of Jerusalem, Israel</font></div><div style="font-size:12.8px;letter-spacing:0.2px;word-wrap:break-word"><font size="2">Phone: +972-50-471-4621<br>web: <a href="https://kaushalgianchandani.github.io/" target="_blank">https://kaushalgianchandani.github.io</a></font></div></div></div></div></div></div></div></div>