<div><font>Hi John,</font></div><div><font><br></font></div><div><font>Not sure if you have modified the code but I always specify the actual vertical positions (not fractal indice) in the flt input files. I found these in README.flt (</font><a href="https://github.com/MITgcm/MITgcm/blob/master/pkg/flt/README.flt">https://github.com/MITgcm/MITgcm/blob/master/pkg/flt/README.flt</a>):</div><div><font><br></font></div><div><font><pre style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace; font-size: 12px; margin-top: 0px; margin-bottom: 0px; color: rgb(36, 41, 46);">c Each float contains a 9 element double precision record of a
c direct access file. The records are:
c
c - npart A unique float identifier (1,2,3,...)
c - tstart start date of integration of float (in s)
c Note: If tstart=-1 floats are integrated right from the
c beginning
<b>c - xpart x position of float (in units of XC)
c - ypart y position of float (in units of YC)
c - kpart actual vertical level of float</b>
c - kfloat target level of float (should be the same as kpart at
c the beginning)
c - iup flag if the float
c - should profile ( > 0 = return cycle (in s) to surface)
c - remain at depth ( = 0 )
c - is a 3D float ( = -1 ).
c - should be advected WITHOUT additional noise ( = -2 ).
c (This implies that the float is non-profiling)
c - is a mooring ( = -3 ), i.e. the float is not advected
c - itop time of float the surface (in s)
c - tend end date of integration of float (in s)
c Note: If tend=-1 floats are integrated till the end of
c the integration</pre></font></div><div><font><br></font></div><div><sign signid="0"><div><font>And if you are a pythoner you may want to check this repo (</font><a href="https://github.com/rabernat/floater/blob/master/floater/generators.py">https://github.com/rabernat/floater/blob/master/floater/generators.py</a>). </div><div><font><br></font><font>Hope this helps.<br></font><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 (Ç®îÚÀ¤) <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;">------------------ Original ------------------</div><div style="FONT-SIZE: 12px;background:#efefef;padding:8px;"><div id="menu_sender"><b>From: </b> "John Paul Irving"<jpi18@my.fsu.edu>;</div><div><b>Date: </b> Tue, Mar 31, 2020 11:37 PM</div><div><b>To: </b> "MITgcm-support@mitgcm.org"<MITgcm-support@mitgcm.org>; <wbr></div><div></div><div><b>Subject: </b> [MITgcm-support] MITgcm Floats Package Depth Interpolation Issue</div></div><div> </div><div style="position:relative;"><div id="tmpcontent_res"></div>
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Hello All,</div>
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I am working on a project utilizing the MITgcm flt package. I am running the model on a curvilinear grid with multiple processors. In my flt input files i prescribe the vertical position of the flts in fractal indices, and the FLT_MAP_K2R function in the flt_mapping.F
file converts these fractal indices to a depth in meters. However the floats are not being mapped to their exact positions in the simulation. For particles launched between 50-500 meters, the initial starting positions are less than 1m off the desired depth.
But for particles at 1000m launch depth, they are about 20 meters off. I have 45 vertical levels as follows. the dz between layers is 10m in the upper150m, 25m until 600m, 50m until 1000, and then with larger levels to the bottom.</div>
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I am having trouble figuring out why it cannot interpolate the exact depth values that i originally used to interpolate to an indice? I also have confusion about why 2 floats launched at the same depth are then read in at slightly different depths?</div>
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Was wondering if anyone else has tried to do this and seen this issue, thanks!</div>
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<p style="margin-top: 0px; margin-bottom: 0px">jpi18@my.fsu.edu</p>
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<p style="margin-top: 0px; margin-bottom: 0px">Department of Earth, Ocean, & Atmospheric Science</p>
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<p style="margin-top: 0px; margin-bottom: 0px;margin-top:0; margin-bottom:0">John Irving</p>
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