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<div>just a wild guess, for using the regridded dataset, did you unset the following flag in EXF_OPTIONS.h during compilation:</div>
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<div>C- Use spatial interpolation to interpolate</div>
<div>C forcing files from input grid to model grid.</div>
<div>#undef USE_EXF_INTERPOLATION</div>
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<div>or alternatively, did you set following flag to 0 in data.exf during runtime</div>
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<div>C {inputField}_interpMethod :: interpolation method: =0 : no interpolation ;</div>
<div>C :: =1,11,21 : bilinear ; =2,12,22 : bicubic ;</div>
<div>C :: =1,2 for tracer ; =11,12 for U ; =21,22 for V.</div>
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<div>D.</div>
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<blockquote type="cite">
<div>On Feb 9, 2023, at 8:30 AM, Dani Jones <dcjones.work@gmail.com> wrote:</div>
<br class="Apple-interchange-newline">
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<div dir="ltr">Hi Oliver,
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<div>You've found the error! Well spotted. By changing `field_lat_inc = 0.25` to `field_lat_inc = 249*0.25` throughout, where Ny=249 is the number of latitude points in my ERA5 subset, I was able to get sensible-looking EXF diagnostics output. <br>
<br>
I am still a bit surprised that using a regridded dataset didn't fix my issue, though. I was thinking that I could regrid the ERA5 data onto the model grid, comment out the interpolation-related grid parameters in `data.exf`, and use the default values. Oddly,
this didn't work. I might do some more tests on this later, but for now I'm happy to have something that runs. <br>
<br>
Thanks again!<br>
<br>
Best wishes,<br>
Dan(i)</div>
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<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Thu, Feb 9, 2023 at 3:34 PM Oliver Jahn <<a href="mailto:jahn@mit.edu">jahn@mit.edu</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 Dan,<br>
<br>
I noticed one thing in your data.exf: there is only 1 value for vwind_lat_inc which is an array. You have to provide vwind_nlat-1 values. (This is needed for things like Gaussian grids but definitely could use more coverage in the docs!)<br>
<br>
Oliver<br>
<br>
<br>
On 2023-02-09 09:16, Dani Jones wrote:<br>
> Hello MITgcm-support listers,<br>
> <br>
> I am having trouble with the EXF package while trying to force a <br>
> regional model configuration using external fields derived from ERA5. <br>
> The diagnostics output from EXF shows horizontal stripes or distorted <br>
> results.<br>
> <br>
> To set up my configuration, I followed these steps:<br>
> <br>
> * Downloaded a subset of ERA5 using the cdsapi package<br>
> * Regridded the data onto my model grid using the xESMF package<br>
> * Ran MITgcm for a few timesteps and checked the EXF diagnostics output <br>
> <br>
> I have conducted various checks and tried different approaches to <br>
> resolve the issue, including:<br>
> <br>
> * Examined the contents of the ERA5 data<br>
> * Examined the binary files for any problems<br>
> * Tried "on the fly" interpolation with EXF and repeatedly checked the<br>
> data.exf parameters<br>
> * Checked the precision and endian-ness throughout the entire process<br>
> * Created binary files using Matlab and Python<br>
> * Updated to the latest version of MITgcm and recompiled with the<br>
> -D_BYTESWAPIO flag<br>
> * Tried every permutation of the dimensions for the binary files <br>
> <br>
> Despite these efforts, the binary files appear to be fine, and it seems <br>
> that MITgcm/EXF is not reading them as expected. For further information <br>
> and details, I have documented this issue on GitHub with plots from the <br>
> diagnostics package and links to relevant files:<br>
> <br>
> <a href="https://urldefense.us/v3/__https://github.com/so-wise/so-wise-gyre/issues/34__;!!PvBDto6Hs4WbVuu7!cM_FgSyA7SS_rYeOdAm6pNa9WR4JGr_Kbv0SGzwI5YCzNrN0mLBfK4eskiRcUE0mNcSjKDrD3xk$" rel="noreferrer" target="_blank">
https://github.com/so-wise/so-wise-gyre/issues/34</a> <br>
> <<a href="https://urldefense.us/v3/__https://github.com/so-wise/so-wise-gyre/issues/34__;!!PvBDto6Hs4WbVuu7!cM_FgSyA7SS_rYeOdAm6pNa9WR4JGr_Kbv0SGzwI5YCzNrN0mLBfK4eskiRcUE0mNcSjKDrD3xk$" rel="noreferrer" target="_blank">https://github.com/so-wise/so-wise-gyre/issues/34</a>><br>
> <br>
> Thanks in advance for any assistance, guidance, or suggestions that you <br>
> can provide.<br>
> <br>
> Best regards,<br>
> Dan(i)<br>
> <br>
> --<br>
> *Dr Dan(i) Jones* • Physical Oceanographer<br>
> Polar Oceans Team <<a href="https://urldefense.us/v3/__https://www.bas.ac.uk/team/science-teams/oceans/__;!!PvBDto6Hs4WbVuu7!cM_FgSyA7SS_rYeOdAm6pNa9WR4JGr_Kbv0SGzwI5YCzNrN0mLBfK4eskiRcUE0mNcSjp-0_INE$" rel="noreferrer" target="_blank">https://www.bas.ac.uk/team/science-teams/oceans/</a>>•
<br>
> BAS AI Lab <<a href="https://urldefense.us/v3/__https://www.bas.ac.uk/project/ai__;!!PvBDto6Hs4WbVuu7!cM_FgSyA7SS_rYeOdAm6pNa9WR4JGr_Kbv0SGzwI5YCzNrN0mLBfK4eskiRcUE0mNcSjjQBycJY$" rel="noreferrer" target="_blank">https://www.bas.ac.uk/project/ai</a>> • British
Antarctic Survey <br>
> <<a href="https://urldefense.us/v3/__https://www.bas.ac.uk/__;!!PvBDto6Hs4WbVuu7!cM_FgSyA7SS_rYeOdAm6pNa9WR4JGr_Kbv0SGzwI5YCzNrN0mLBfK4eskiRcUE0mNcSjqsRZZC4$" rel="noreferrer" target="_blank">https://www.bas.ac.uk/</a>><br>
> Website <<a href="https://urldefense.us/v3/__http://www.danjonesocean.com/__;!!PvBDto6Hs4WbVuu7!cM_FgSyA7SS_rYeOdAm6pNa9WR4JGr_Kbv0SGzwI5YCzNrN0mLBfK4eskiRcUE0mNcSjH4_li0w$" rel="noreferrer" target="_blank">http://www.danjonesocean.com/</a>> • Twitter
<br>
> <<a href="https://urldefense.us/v3/__https://twitter.com/DanJonesOcean__;!!PvBDto6Hs4WbVuu7!cM_FgSyA7SS_rYeOdAm6pNa9WR4JGr_Kbv0SGzwI5YCzNrN0mLBfK4eskiRcUE0mNcSj2Bs7HCo$" rel="noreferrer" target="_blank">https://twitter.com/DanJonesOcean</a>> • they/them<br>
> <br>
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