<p dir="ltr">Thanks guys for this useful piece of information. I have 32cpus and 2 nodes. I am testing many convective schemes over East Africa. If I got you right, if my data is at 83km, then the outer nest should be between 5-3 times less, that means the inner nest will be about 9.33km if ratio 1.3 is considered. My confusion is 9km is too expensive to run than 28 or 32km. For my case do I set the domain such that the inner nest is 28km or what??. This is because the if outer nest is 32km then inner must be 10.5km there about which is too expensive. <br><br></p>
<div class="gmail_extra"><br><div class="gmail_quote">On Jul 25, 2016 9:05 PM, "Mike Dvorak" <<a href="mailto:mike@sailtactics.com">mike@sailtactics.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<p>Hi there,</p>
<p>You typically don't have to start with your first domain at the
same resolution of the input dataset. I would start out with
something on the order of 3 to 5 times smaller in delta x and y.
So if your input data is 83 km, your WRF parent (first) domain
could be roughly between 28 to 16 km.</p>
<p>You might run some sensitivity experiments to see how well the
model matches observations by going directly to 16 km. The results
might be good enough for your purposes and would save you having
to run that extra domain. Removing parent domains does <i>not</i>
often make a huge difference in wallclock time because the inner
nests run multiple timesteps for each time the parent domains
runs.</p>
<p>Best of luck with your experiment.<br>
</p>
<p>Cheers,<br>
Mike<br>
</p>
<br>
<div>On 07/24/2016 09:34 AM, afwande juliet
wrote:<br>
</div>
<blockquote type="cite">
<p dir="ltr">Dear users <br>
I am running wrf using era interim which is at 83km resolution.
I am downscaling to about 16KM nest <br>
It's very slow. I even deactivated the parent domain so that I
only get output from nest to reduce runtime but still takes
84hrs to run 3months simulation which is too slow. </p>
<p dir="ltr">What would be the danger if I run without nest to
reduce runtime </p>
<p dir="ltr">Would there be any mismatch between the driving data
and the model </p>
<br>
<fieldset></fieldset>
<br>
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