<div><font>Hi Ryan,</font></div><div><font><br></font></div><div>I have recently tried to add a body forcing to mimic the M2 tide</div><div>in a channel model (in 2D x-z plane). It is quite easy to implement</div><div>this by adding some code snippets in 'apply_forcing.F' (see attached).</div><div>I found these codes somewhere on the web (but do not remember now).</div><div>Its effect can be seen in this animation:</div><div>https://github.com/miniufo/InternalWaveBreaking</div><div><br></div><div>Notice that it is applied to the first 5 tiles (bi.LT.5). Hope this helps.</div><div><sign signid="0"><div><font><br></font><div style="color:#909090;font-family:Arial Narrow;font-size:12px"></div></div><div style="font-size:14px;font-family:Verdana;color:#000;"><div> <font size="2">Best regards <br> <br>Yu-Kun Qian (钱钰坤) <br>Center for Monsoon and Environment Research</font> </div> <font size="2">Department of Atmospheric Sciences<br>School of Environmental Science and Engineering<font size="2"> <br> </font>Sun Yat-sen University <br>No. 135 Xingang West Road, Haizhu District <br>Guangzhou, 510275, P.R. China <br>Tel; 020-84115227 <br>Email: <a href="mailto:qianyk@mail2.sysu.edu.cn">qianyk@mail3.sysu.edu.cn</a> </font>
<div> <font size="2"> </font> </div></div></sign></div><div> </div><div><includetail><div> </div><div> </div><div style="font:Verdana normal 14px;color:#000;"><div style="FONT-SIZE: 12px;FONT-FAMILY: Arial Narrow;padding:2px 0 2px 0;">------------------ 原始邮件 ------------------</div><div style="FONT-SIZE: 12px;background:#efefef;padding:8px;"><div id="menu_sender"><b>发件人:</b> "Ryan Abernathey"<ryan.abernathey@gmail.com>;</div><div><b>发送时间:</b> 2021年12月3日(星期五) 晚上10:21</div><div><b>收件人:</b> "MITgcm-support"<mitgcm-support@mitgcm.org>; <wbr></div><div></div><div><b>主题:</b> Re: [MITgcm-support] Tides in channel model</div></div><div> </div><div style="position:relative;"><div id="tmpcontent_res"></div><div dir="ltr">Thanks for the reply Stanislav! <div><br></div><div>In this case, Qiyu is working with a zonally reentrant channel (similar to <a href="https://mitgcm.readthedocs.io/en/latest/examples/reentrant_channel/reentrant_channel.html">https://mitgcm.readthedocs.io/en/latest/examples/reentrant_channel/reentrant_channel.html</a>), so there is no open boundary at which to apply tidal forcing. So although it is a small domain, it is more similar to a global model in this respect.</div><div><br></div><div>My understanding was that the most common way to force tides in global models was via a specified surface pressure field in the EXF package. (E.g. that's how the LLC4320 simulations were forced.) But I also know there has been a lot of recent work in this area, so maybe there is a simpler option.</div><div><br></div><div>Has anyone tried specifying a body force in analytic form using a custom code file? Where would be the right place in the code to insert such a forcing?</div><div><br></div><div>Best,</div><div>Ryan</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Dec 3, 2021 at 4:18 AM Stanislav Martyanov <<a href="mailto:martyanov.sd@gmail.com">martyanov.sd@gmail.com</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="ltr">Hello Qiyu,<div><br><div>the easiest way is to generate a simple grid with constant dx (and/or dy) with one or several open boundaries specified in OBCS_OPTIONS.h (#define ALLOW_OBCS_NORTH, etc). Then, you will need to configure the open boundary conditions (if you specify induced tide) and external forcing (if you want to set geopotantial): i.e. #define OBCS_ALLOW_TIDES in OBCS_OPTIONS.h, and #define EXT_ALLOW_TIDES in EXT_OPTIONS.h</div><div><br></div><div>And, of course, you need to set the corresponding filenames with the tidal forcing in data.obcs (and in data.exf, if you want geopotential). Note that only the normal component of tidal current at the open boundaries is currently implemented in the model.</div><div><br></div><div>You also should get familiar with the OBCS package where tides can be specified (as open boundary conditions), and with the EXF package where tides can be added through geopotental.</div><div><br></div><div>Best,</div><div>Stanislav</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">ср, 1 дек. 2021 г. в 21:50, Qiyu Xiao <<a href="mailto:qx344@nyu.edu" target="_blank">qx344@nyu.edu</a>>:<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="ltr"><div>Dear MITgcm users/developers,</div><div><br></div><div>If I want to run a channel model with tides, what is the best way to do that? What functions/variables should I change or is there any package for this purpose? <br></div><div><br></div><div>Thanks,</div><div>Qiyu<br></div></div>
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