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<div class="moz-cite-prefix">The grib header is correct.<br>
Let us denote the data from 6 hourly output as C1, C2, C3, C4, C5,
C6.<br>
<br>
To get hourly mean, then<br>
for hour 1, the mean is C1,<br>
for hour 2, the mean is 2C2-C1<br>
for hour 3, the mean is 3C3-2C2<br>
for hour 4, the mean is 4C4-3C2<br>
for hour 5, the mean is 5C5-4C4<br>
and for hour 6, it is 6C6-5C5<br>
<br>
This pattern repeats every six ours.<br>
I hope this helps.<br>
Moorthi<br>
On 11/02/2016 07:41 PM, Sam Wilson wrote:<br>
</div>
<blockquote cite="mid:D43FC693.123283%25sam@surfline.com"
type="cite">
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charset=windows-1252">
<div>
<div>Hi Jeff,</div>
<div><br>
</div>
<div>I plotted a quick and dirty cloud animation using the data
- each step is 1 hour from f001 through f015 in the attached.</div>
<div><br>
</div>
<div>It appears that they are averages over time - you can see
the bigger jumps at steps 8 and 14 (the transition from 0-6hr
avg to 6-7hr and from 6-12hr avg to 12-13hr).</div>
<div><br>
</div>
<div>Marian - thank you for the feedback. Sounds like using the
hourly data for cloud cover may not be a good idea, unless
someone else has a solution.</div>
<div><br>
</div>
</div>
<div>Thanks,</div>
<div>Sam</div>
<div><br>
</div>
<span id="OLK_SRC_BODY_SECTION">
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<span style="font-weight:bold">From: </span><<a
moz-do-not-send="true"
href="mailto:gradsusr-bounces@gradsusr.org">gradsusr-bounces@gradsusr.org</a>>
on behalf of Jeff Duda <<a moz-do-not-send="true"
href="mailto:jeffduda319@gmail.com">jeffduda319@gmail.com</a>><br>
<span style="font-weight:bold">Reply-To: </span>GrADS Users
Forum <<a moz-do-not-send="true"
href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a>><br>
<span style="font-weight:bold">Date: </span>Wednesday,
November 2, 2016 at 3:21 PM<br>
<span style="font-weight:bold">To: </span>GrADS Users Forum
<<a moz-do-not-send="true"
href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a>><br>
<span style="font-weight:bold">Subject: </span>Re: [gradsusr]
GFS total cloud cover<br>
</div>
<div><br>
</div>
<div>
<div>
<div dir="ltr">
<div>
<div>
<div>Sam,<br>
</div>
That might just be a wgrib table thing. Have you
actually plotted the field over those times? If it's
truly an averaged field, you should be able to see
some indication of that in the texture and smoothness
of the fields as you progress through increasing
averaged times. <br>
<br>
</div>
My guess is that this is just some arbitrary setting in
wgrib and does not reflect the true nature of the field.
But I could be wrong. If there are any NCEP folks who
work on the GFS on this forum, perhaps one of them could
set the record straight.<br>
<br>
</div>
Jeff <br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Nov 2, 2016 at 4:54 PM,
Sam Wilson <span dir="ltr">
<<a moz-do-not-send="true"
href="mailto:sam@surfline.com" target="_blank">sam@surfline.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div
style="word-wrap:break-word;color:rgb(0,0,0);font-size:14px;font-family:Calibri,sans-serif">
<div>
<div>Thanks for the response Jeff - it’s strange
to me as well!</div>
<div><br>
</div>
<div>Running wgrib2 on the data files for forecast
hours 001 through 007 gives the following for
TCDCclm:</div>
<div><br>
</div>
<div><b>f001:</b></div>
<div>17:7991683:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>0-1</b> hour ave fcst:</div>
<div><b>f002:</b></div>
<div>17:8082626:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>0-2</b> hour ave fcst:</div>
<div><b>f003:</b></div>
<div>17:8059826:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>0-3 </b>hour ave fcst:</div>
<div><b>f004:</b></div>
<div>17:8057865:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>0-4</b> hour ave fcst:</div>
<div><b>f005:</b></div>
<div>17:8119289:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>0-5</b> hour ave fcst:</div>
<div><b>f006:</b></div>
<div>17:8172510:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>0-6</b> hour ave fcst:</div>
<div><b>f007:</b></div>
<div>17:8013825:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>6-7</b> hour ave fcst:</div>
<div><br>
</div>
<div>And it continues on..once the files go to 3
hourly (after hour 120), we have:</div>
<div><br>
</div>
<div><b>f123:</b></div>
<div>17:7687687:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>120-123</b> hour ave fcst:</div>
<div><b>f126:</b></div>
<div>17:7778871:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>120-126</b> hour ave fcst:</div>
<div><b>f129:</b></div>
<div>17:7728042:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>126-129</b> hour ave fcst:</div>
<div><br>
</div>
<div>And finally the 12 hourly files (past hour
240) are all just 12 hour average forecasts:</div>
<div><br>
</div>
<div><b>f252:</b></div>
<div>17:6845416:d=2016110212:TCDC:<wbr>entire
atmosphere:<b>240-252</b> hour ave fcst:</div>
<div><br>
</div>
<div>I did think about the method you suggested
(tcdcclm - tcdcclm(t-1)) but stopped there for
the reason you mentioned..</div>
<div>
<div><br>
</div>
<div>Strange indeed - unless I’m missing
something..</div>
<div><br>
</div>
<div>Thanks,</div>
<div>Sam</div>
</div>
</div>
<div><br>
</div>
<span id="m_1177070826903731705OLK_SRC_BODY_SECTION">
<div
style="font-family:Calibri;font-size:11pt;text-align:left;color:black;BORDER-BOTTOM:medium
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1pt solid;BORDER-RIGHT:medium
none;PADDING-TOP:3pt">
<span style="font-weight:bold">From: </span><<a
moz-do-not-send="true"
href="mailto:gradsusr-bounces@gradsusr.org"
target="_blank">gradsusr-bounces@gradsusr.org</a><wbr>>
on behalf of Jeff Duda <<a
moz-do-not-send="true"
href="mailto:jeffduda319@gmail.com"
target="_blank">jeffduda319@gmail.com</a>><br>
<span style="font-weight:bold">Reply-To: </span>GrADS
Users Forum <<a moz-do-not-send="true"
href="mailto:gradsusr@gradsusr.org"
target="_blank">gradsusr@gradsusr.org</a>><br>
<span style="font-weight:bold">Date: </span>Wednesday,
November 2, 2016 at 2:08 PM<br>
<span style="font-weight:bold">To: </span>GrADS
Users Forum <<a moz-do-not-send="true"
href="mailto:gradsusr@gradsusr.org"
target="_blank">gradsusr@gradsusr.org</a>><br>
<span style="font-weight:bold">Subject: </span>Re:
[gradsusr] GFS total cloud cover<br>
</div>
<div><br>
</div>
<div>
<div>
<div dir="ltr">
<div>
<div>It seems a little strange to me that
the total cloud cover product would be
averaged over time. Is that really the
case?<br>
<br>
</div>
Anyway, if you really do have an average
over overlapping and increasing windows,
with nothing else to go on and without
applying the equations of motion in
reverse, you'd have to assume a linear
averaging, so subtraction of subsequent
slices of the field (i.e., tcdcclm -
tcdcclm(t-1)) would give you piecewise
temporal averages. However, that method
would give you negative cloud cover values
which is clearly nonsensical, which again
is why I question whether or not that
array contains a temporal average. That
just doesn't make a lot of sense.<br>
<br>
</div>
Jeff Duda<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Nov 2, 2016
at 3:27 PM, Sam Wilson <span dir="ltr">
<<a moz-do-not-send="true"
href="mailto:sam@surfline.com"
target="_blank">sam@surfline.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex">
<div
style="word-wrap:break-word;color:rgb(0,0,0);font-size:14px;font-family:Calibri,sans-serif">
<div>Hi,</div>
<div><br>
</div>
<div>I’m working with hourly GFS total
cloud cover (TCDCclm) and I’m a bit
stumped on the following..</div>
<div><br>
</div>
<div>Given TCDCclm for hours 0-1, 0-2,
0-3, 0-4, 0-5, and 0-6, what is the
proper way to determine TCDCclm for
hours 1-2, 2-3, 3-4, 4-5, and 5-6?</div>
<div><br>
</div>
<div>I may be making the problem more
difficult than it is..but wanted to
ping this group to be sure.</div>
<div><br>
</div>
<div>
<div>Is there an existing grads
script that handles this already
and if not, does anyone here have
any insight?</div>
</div>
<div><br>
</div>
<div>Thanks so much for your time.</div>
<div><br>
</div>
<div>Best,</div>
<div>Sam</div>
</div>
<br>
______________________________<wbr>_________________<br>
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<br>
<span class="HOEnZb"></span></blockquote>
<span class="HOEnZb"></span></div>
<span class="HOEnZb"><font color="#888888"><br>
<br clear="all">
<br>
-- <br>
<div
class="m_1177070826903731705gmail_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>
</font></span></div>
</div>
</div>
</span></div>
<br>
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<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>
</div>
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</span>
<br>
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<p><br>
</p>
<pre class="moz-signature" cols="72">--
Dr. Shrinivas Moorthi
Research Meteorologist
Global Climate and Weather Modeling Branch
Environmental Modeling Center / National Centers for Environmental Prediction
5830 University Research Court - (W/NP23), College Park MD 20740 USA
Tel:(301)683-3718</pre>
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