<div dir="ltr"><div><div><div><div><div><div><div><div><div><div><div><div><div><div>'set t 2'<br></div>'d apcpsfc'<br></div>should display 1-hr precip accumulation between f00 and f01<br><br></div>'set t 3'<br></div>'d apcpsfc'<br></div>should display 2-hr precip accumulation between f00 and f02<br><br></div>'set t 4'<br></div>'d apcpsfc'<br></div>should display 3-hr precip accumulation between f00 and f03<br><br></div>'set t 5'<br></div>'d apcpsfc'<br></div>should display 1-hr precip accumulation between f03 and f04<br><br>...<br>...<br>...<br><br></div>and so on.<br><br></div>If you want to display 1-hr precip at "off" hours (not f01, f04, f07, ...) then yes, you need to display the difference over consecutive hours. <br>f02: 'set t 3' ; 'd apcpsfc - apcpsfc(t-1)'<br>f03: 'set t 4' ; 'd apcpsfc - apcpsfc(t-1)'<br><br>Notice how the pattern is the same despite the particular time. The only exception is at f01, f04, f07, ... when you just display apcpsfc without any subtraction.<br><br>You appear to have this idea. Is this not getting you the results you expect?<br><br></div>Jeff<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Oct 14, 2016 at 12:26 PM, Mark Sponsler <span dir="ltr"><<a href="mailto:msponsler@comcast.net" target="_blank">msponsler@comcast.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>Hi Jeff,</div>
<div>Thanks for the info. </div>
<div></div>
<div>Yeah, I use the first time step which of course has no precip data in it. So the cycle would start with t = 2.</div>
<div></div>
<div>Just to confirm, for either the 1 hr NAM or the 3 hr NAM, I simply should use the below logic and all should be good?</div>
<div></div>
<div>In other words, the 1 hr NAM accumulates in 3 time step sequential bundles (timesteps 2,3,4 refresh then 5,6,7, refresh etc) and the 3 hr NAM accumulates the same. </div><span class="">
<div></div>
<div>Display Time = 2<br>Time 3 = Time 3 - Time 2<br>Display Time 3<br>Time 4 = Time 4 - Time 3<br>Display Time 4</div>
<div></div>
</span><div>Display Time = 5</div>
<div>Time 6 = Time 6 - Time 5</div>
<div>Display Time 6</div>
<div>Time 7 = Time 7 - Time 6</div>
<div>Display Time 7</div>
<div></div>
<div>etc...</div>
<div></div>
<div><span style="font-size:small">Thanks,<br>Mark</span></div><div class="HOEnZb"><div class="h5">
<div></div>
<div></div>
<div>----- Original Message -----<br>From: Jeff Duda <<a href="mailto:jeffduda319@gmail.com" target="_blank">jeffduda319@gmail.com</a>><br>To: GrADS Users Forum <<a href="mailto:gradsusr@gradsusr.org" target="_blank">gradsusr@gradsusr.org</a>><br>Sent: Fri, 14 Oct 2016 16:59:14 -0000 (UTC)<br>Subject: Re: [gradsusr] NAM and APCPSFC data</div>
<div></div>
<div dir="ltr">
<div>
<div>Mark,</div>
Why do you not think it works the way you described in (1)? That's the way I've always used it, and I've never had a problem. The particular t-index value you use in grads depends on how you setup the control file. If you didn't start the time index at forecast hour 0, then there will be a phase difference between what you think and what actually works.<br>
<div></div>
</div>
Jeff Duda</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Oct 14, 2016 at 10:55 AM, Mark Sponsler <span dir="ltr"><<a href="mailto:msponsler@comcast.net" target="_blank">msponsler@comcast.net</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>Hi,<br>I'm trying to display variable 'apcpsfc' from the 3 hr and 1 hr NAM. The resulting images appear to pulsate/accumulate precip every few images then reset only to accumulate again.<br>
<div></div>
I've seen the threads in the archive on this issue with HD GFS data, but I'm trying to understand 2 things:<br>
<div></div>
1) What is the accumulation period for NAM 1 hr and 3 hr data. I was thinking it was every 3 time steps (i.e. excluding time step 1 / 00 hr), it is 2, 3, 4 then reset and start accumulating again for the next 3 time steps 5, 6 and 7). But that doesnt seem to be the case. <br>
<div></div>
2) What does it mean to 'normalize' the data? Westly did something in wgrib2 for HD GFS data to normalize it and I was wondering if that was also applicable to NAM data. What is done to mathmatically to get the data to be valid for just a single timestep?. Can I write something in GRDADS to perform the normalization rather than having to use WGRIB2. <br>
<div></div>
Assuming the accumulation theory is correct (that apcpsfc accumulates every three time steps), I've been trying to write code to remove the accumulation by:<br>
<div></div>
Display Time = 2<br>Time 3 = Time 3 - Time 2<br>Display Time 3<br>Time 4 = Time 4 - Time 3<br>Display Time 4<br>
<div></div>
But it doesnt work. <br>
<div></div>
Any help would be appreciated.<br>
<div></div>
Thanks,<br>Mark </div>
<div></div>
<div></div>
<div><span style="font-size:small">Thanks,<br>Mark</span></div>
<br>______________________________<wbr>_________________<br>
<div></div>
gradsusr mailing list<br><a href="mailto:gradsusr@gradsusr.org" target="_blank">gradsusr@gradsusr.org</a><br><a href="http://gradsusr.org/mailman/listinfo/gradsusr" rel="noreferrer" target="_blank">http://gradsusr.org/mailman/<wbr>listinfo/gradsusr</a><br>
<div></div>
</blockquote>
</div>
<br><br clear="all"><br>-- <br>
<div class="m_-6991840824023508013gmail_signature">
<div dir="ltr">
<div>Jeff Duda<br>Post-doctoral research associate<br>University of Oklahoma School of Meteorology</div>
</div>
</div>
</div>
<div></div>
<div></div></div></div><br>______________________________<wbr>_________________<br>
gradsusr mailing list<br>
<a href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a><br>
<a href="http://gradsusr.org/mailman/listinfo/gradsusr" rel="noreferrer" target="_blank">http://gradsusr.org/mailman/<wbr>listinfo/gradsusr</a><br>
<br></blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div>Jeff Duda<br>Post-doctoral research associate<br>University of Oklahoma School of Meteorology<br></div></div></div>
</div>