[Met_help] [rt.rap.ucar.edu #41771] History for Gridded Observations Question (UNCLASSIFIED)

[RAL HelpDesk {for John Halley Gotway}]

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  Initial Request
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Classification: UNCLASSIFIED
Caveats: NONE

I'm looking for sources of gridded observations to be used for Grid-Stat and
MODE and propose some experiments to validate a possible source I have access
to here at ARL.

Please read over the attached document which explains what we are looking for
and the experiments.

The attached slides summarize the experiments and are referenced in the
document.

We would appreciate your feedback on the experiments.

Thanks.

R/
John

Mr John W. Raby, Meteorologist
U.S. Army Research Laboratory
White Sands Missile Range, NM 88002
(575) 678-2004 DSN 258-2004
FAX (575) 678-1230 DSN 258-1230
Email: john.raby at us.army.mil

Please begin using the email address within this signature
block for all future correspondence.  The current @arl.army.mil
address will be decommissioned in upcoming months.

"When you can measure what you are speaking about and express it in numbers,
you know something about it, but when you cannot measure it, when you cannot
express it in number, your knowledge is of a meagre and unsatisfactory
kind". - Lord Kelvin



Classification: UNCLASSIFIED
Caveats: NONE




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  Complete Ticket History
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Subject: Re: [rt.rap.ucar.edu #41771] Gridded Observations Question (UNCLASSIFIED)
From: John Halley Gotway
Time: Wed Oct 27 14:35:31 2010

John,

I read through the documents you sent.  Based on what I read, I see
two questions in here:

(1) Have we used the NWS RTMA data in our work?
(2) How should you design an experiment to determine if using the WRF-
N Analysis as a pseudo-observation field is reasonable to do?

The answer to your first question is no.  To my knowledge, we have not
used the RTMA in any of our evaluation exercises.  However, I went
hunting around and found a link for the current day's data here:
   ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndgd/GT.rtma/AR.conus
The data on this site is GRIB2 format, which MET does not support
*yet*.  So I retrieved one of the GRIB2 files and converted it to
GRIB1 using the "cnvgrib" utility.  I see that the RTMA data is
defined over CONUS on a 2.5km grid which would meet your resolution
criteria.  It looks like the RTMA fields include 2-meter temperature
and temperature dewpoint, not relative humidity.

Regarding your second question, my inclination would be to pursue
Robert Dumais' approach of withholding 1/3 of the observations from
the data assimilation and using them for the verification.  Now
I'm not a statistician, so I can't offer much advice on this
experimental design other than to say I've generally seen that type of
approach done in the past.  But I'm sure there are a lot of other
details/decisions regarding how best to design the experiment.  I've
copied Tressa on this message so she can weigh in with any advice she
might have.

As for how to proceed, it is of course, up to you.  It seems to me
that using the WRE-N analysis and/or the RTMA are reasonable
alternatives.

Hope that helps.

John

On 10/27/2010 10:43 AM, RAL HelpDesk {for Raby, John} wrote:
>
> Wed Oct 27 10:43:50 2010: Request 41771 was acted upon.
> Transaction: Ticket created by john.raby at us.army.mil
>        Queue: met_help
>      Subject: Gridded Observations Question (UNCLASSIFIED)
>        Owner: Nobody
>   Requestors: john.raby at us.army.mil
>       Status: new
>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=41771 >
>
>
> Classification: UNCLASSIFIED
> Caveats: NONE
>
> I'm looking for sources of gridded observations to be used for Grid-
Stat and
> MODE and propose some experiments to validate a possible source I
have access
> to here at ARL.
>
> Please read over the attached document which explains what we are
looking for
> and the experiments.
>
> The attached slides summarize the experiments and are referenced in
the
> document.
>
> We would appreciate your feedback on the experiments.
>
> Thanks.
>
> R/
> John
>
> Mr John W. Raby, Meteorologist
> U.S. Army Research Laboratory
> White Sands Missile Range, NM 88002
> (575) 678-2004 DSN 258-2004
> FAX (575) 678-1230 DSN 258-1230
> Email: john.raby at us.army.mil
>
> Please begin using the email address within this signature
> block for all future correspondence.  The current @arl.army.mil
> address will be decommissioned in upcoming months.
>
> "When you can measure what you are speaking about and express it in
numbers,
> you know something about it, but when you cannot measure it, when
you cannot
> express it in number, your knowledge is of a meagre and
unsatisfactory
> kind". - Lord Kelvin
>
>
>
> Classification: UNCLASSIFIED
> Caveats: NONE
>
>
>

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