<div dir="ltr">Hello Juliet,<div><br></div><div>As Mike pointed out you can run the simulation without nest. As your input is 83 KM resolution your domain can be 3-5 folds resolution of the input data. Since your input is 83 KM you can run with a domain of size 16.6 KM. You need not run a new for that. As Mike suggested you can run use 16 KM as domain and run sensitivity experiment to check your outputs are fine</div><div><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Jul 26, 2016 at 1:21 AM, <span dir="ltr"><<a href="mailto:wrf-users-request@ucar.edu" target="_blank">wrf-users-request@ucar.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Send Wrf-users mailing list submissions to<br>
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Today's Topics:<br>
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1. Re: Is it a must to run wrf with a nest (Mike Dvorak)<br>
2. Re: Is it a must to run wrf with a nest (afwande juliet)<br>
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Message: 1<br>
Date: Mon, 25 Jul 2016 10:47:37 -0500<br>
From: Mike Dvorak <<a href="mailto:mike@sailtactics.com">mike@sailtactics.com</a>><br>
Subject: Re: [Wrf-users] Is it a must to run wrf with a nest<br>
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Message: 2<br>
Date: Mon, 25 Jul 2016 22:34:47 +0300<br>
From: afwande juliet <<a href="mailto:afwandej965@gmail.com">afwandej965@gmail.com</a>><br>
Subject: Re: [Wrf-users] Is it a must to run wrf with a nest<br>
To: Mike Dvorak <<a href="mailto:mike@sailtactics.com">mike@sailtactics.com</a>><br>
Cc: wrf users group <<a href="mailto:wrf-users@ucar.edu">wrf-users@ucar.edu</a>><br>
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Thanks guys for this useful piece of information. I have 32cpus and 2<br>
nodes. I am testing many convective schemes over East Africa. If I got you<br>
right, if my data is at 83km, then the outer nest should be between 5-3<br>
times less, that means the inner nest will be about 9.33km if ratio 1.3 is<br>
considered. My confusion is 9km is too expensive to run than 28 or 32km.<br>
For my case do I set the domain such that the inner nest is 28km or what??.<br>
This is because the if outer nest is 32km then inner must be 10.5km there<br>
about which is too expensive.<br>
<br>
<br>
On Jul 25, 2016 9:05 PM, "Mike Dvorak" <<a href="mailto:mike@sailtactics.com">mike@sailtactics.com</a>> wrote:<br>
<br>
> Hi there,<br>
><br>
> You typically don't have to start with your first domain at the same<br>
> resolution of the input dataset. I would start out with something on the<br>
> order of 3 to 5 times smaller in delta x and y. So if your input data is 83<br>
> km, your WRF parent (first) domain could be roughly between 28 to 16 km.<br>
><br>
> You might run some sensitivity experiments to see how well the model<br>
> matches observations by going directly to 16 km. The results might be good<br>
> enough for your purposes and would save you having to run that extra<br>
> domain. Removing parent domains does *not* often make a huge difference<br>
> in wallclock time because the inner nests run multiple timesteps for each<br>
> time the parent domains runs.<br>
><br>
> Best of luck with your experiment.<br>
><br>
> Cheers,<br>
> Mike<br>
><br>
> On 07/24/2016 09:34 AM, afwande juliet wrote:<br>
><br>
> Dear users<br>
> I am running wrf using era interim which is at 83km resolution. I am<br>
> downscaling to about 16KM nest<br>
> It's very slow. I even deactivated the parent domain so that I only get<br>
> output from nest to reduce runtime but still takes 84hrs to run 3months<br>
> simulation which is too slow.<br>
><br>
> What would be the danger if I run without nest to reduce runtime<br>
><br>
> Would there be any mismatch between the driving data and the model<br>
><br>
><br>
> _______________________________________________<br>
> Wrf-users mailing listWrf-users@ucar.eduhttp://<a href="http://mailman.ucar.edu/mailman/listinfo/wrf-users" rel="noreferrer" target="_blank">mailman.ucar.edu/mailman/listinfo/wrf-users</a><br>
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><br>
> --<br>
> [image: Sail Tactics logo]<br>
> Mike Dvorak, PhD<br>
> Founder<br>
> Sail Tactics, LLC<br>
> Corpus Christi, TX<br>
> +1 650-454-5243<br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div>With regards<br><br>Dr.R.Jagannathan <br>Professor & Former Dean<br>Tamil Nadu Agricultural University <br>Coimbatore - 641 003 India <br><br>PHONE: Mob: +91 94438 89891<br><br>DO NOT PRINT THIS E-MAIL UNLESS NECESSARY. THE ENVIRONMENT CONCERNS US ALL.</div></div></div>
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