<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Kunal,<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 29 Jul 2021, at 14:20:40, kunal madkaiker <<a href="mailto:kunal.madkaiker02@gmail.com" class="">kunal.madkaiker02@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="">Thank you all for your suggestions.</div><div class=""><br class=""></div><div class="">Incase I go with option 3, my question is, do I have to select grid points for runoff in X or Y
(1D) direction, or can they be 2D (XZ or YZ)?</div></div></div></blockquote><div><br class=""></div><div>If you choose option 3 with OBCS, you simply have to produce 2D OBCS "slices". In your specific case, if you use northern OB, set a 2D (XZ) slice with all zeros, except in the x-coords where you have the sources of your rivers. If your riverbeds are (for example) 4 cells deep, set in your northern OBC file: V(x-coord,1:4)=V_prescribed (the same for T and S). U=0.</div><div>V_prescribed (entering from the north, hence negative) [m/s] times delX(x-coord) [m] times sum(delZ(1:4)) [m] is your prescribed flow rate.</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class="">If 2D, then how can I force them
through data.obcs.</div></div></div></blockquote><div><br class=""></div><div>River runoff file (series of different slices, if they vary in time) must be treated the same way as the other OBCS files (W, S, E, in your case).</div><div>In data.obcs you have to specify (OB_Jnorth) the x and y coordinates of your river sources (upstream end of each riverbed).</div><div>More details here: <a href="https://mitgcm.readthedocs.io/en/latest/phys_pkgs/obcs.html#tab-phys-pkg-obcs-runtime-flags" class="">https://mitgcm.readthedocs.io/en/latest/phys_pkgs/obcs.html#tab-phys-pkg-obcs-runtime-flags</a></div><div><br class=""></div><div>Anyway, as correctly suggested by Dimitris and Stanislav, it is better to start in a simple way first, and then try more complex approaches, if things don't seem to work properly...</div><div><br class=""></div><div>Kind regards,</div><div><br class=""></div><div>SQ</div><div><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class="">Regards,</div><div class="">Kunal<br class=""></div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jul 29, 2021 at 10:25 AM Stanislav Martyanov <<a href="mailto:martyanov.sd@gmail.com" class="">martyanov.sd@gmail.com</a>> wrote:<br class=""></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="ltr" class="">Hello, Kunal,<div class=""><br class=""></div><div class="">I use option #1 (#define ALLOW_RUNOFF, and corresponding settings in data.ext) for the Kara Sea regional domain, and it works fine. The spatial resolution is also rather high: O(1 km) in horizontal and 2m in vertical. Simulation of thermohaline structure near river estuaries and getting realistic river plumes (at least as much as the resolution allows) also sometimes requires knowing the temperature of riverine waters, which often is not available. As I remember, by default MITgcm takes the local water temperature as the input river water's temperature, but in reality it is not always the case.</div><div class=""><br class=""></div><div class="">Regards,</div><div class="">Stanislav Martyanov</div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">ср, 28 июл. 2021 г. в 13:10, kunal madkaiker <<a href="mailto:kunal.madkaiker02@gmail.com" target="_blank" class="">kunal.madkaiker02@gmail.com</a>>:<br class=""></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="ltr" class=""><div class="">Dear MITgcm users,</div><div class=""><br class=""></div><div class="">I am doing regional simulations in the Northern Indian Ocean. Stratification in Bay of Bengal is controlled by salinity and freshwater flux since many rivers like Ganges, Brahmaputra empty into this basin.</div><div class=""><br class=""></div><div class="">I am not able to properly simulate my temp, salinity and currents into the Head bay region of BoB as I am unable to produce an equatorward flow in my domain. Freshwater increases in this region during month of JJAS due to melting of Himalayan glaciers.</div><div class=""><br class=""></div><div class="">I have gone through previously asked similar questions about river runoff and came to know the following possibilities:<br class=""></div><div class=""><br class=""></div>1. To feed at surface through data.exf<br class=""><br class="">2. Feeding a 3-D run-off input using addMassFile<br class=""><br class=""><div class="">3. Through OBCS/ RBCS.</div><div class=""><br class=""></div><div class="">My domain is regional, with small dz and high spatial resolution.</div><div class="">Please let me know which option is the best suited and reliable, since I not only want to improve my temp/ salinity but also to rectify the circulation in head bay region. I would be using Dai et al. (2009) river runoff data.<br class=""></div><div class="">All suggestions are welcome. Attaching figure of my model domain.</div><div class=""><br class=""></div><div class="">Thanks and Regards,</div><div class="">Kunal<br class=""></div></div>
_______________________________________________<br class="">
MITgcm-support mailing list<br class="">
<a href="mailto:MITgcm-support@mitgcm.org" target="_blank" class="">MITgcm-support@mitgcm.org</a><br class="">
<a href="http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support" rel="noreferrer" target="_blank" class="">http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support</a><br class="">
</blockquote></div>
_______________________________________________<br class="">
MITgcm-support mailing list<br class="">
<a href="mailto:MITgcm-support@mitgcm.org" target="_blank" class="">MITgcm-support@mitgcm.org</a><br class="">
<a href="http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support" rel="noreferrer" target="_blank" class="">http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support</a><br class="">
</blockquote></div>
_______________________________________________<br class="">MITgcm-support mailing list<br class=""><a href="mailto:MITgcm-support@mitgcm.org" class="">MITgcm-support@mitgcm.org</a><br class="">http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support<br class=""></div></blockquote></div><br class=""></body></html>