[Met_help] Observation "Level"

Wed Feb 3 12:29:58 MST 2010

Jackie,

Here are a few more questions...

(1) What are the forecast levels that will be used?  Are they pressure levels, like 800mb?  Or are they vertical levels above ground, like 10, 20, 30, 40, 50, 60 meters above ground?

(2) What is the level information for the observations?  It sounds like they're at particular meters above ground level.  Correct?

(3) How would you like those observations levels to be matched to the forecast levels?  For example, suppose you have forecasts of 50 and 60 meters above ground level and an observed value at 57
meters.  Would you want to compare that to the forecast value at 60 meters, or would you want to perform vertical interpolation between the forecasts at 50 and 60 meters?

The answers to those questions will help guide how we could support this.  We've been meaning to enhance our support for verifying at different vertical levels for a while.  And this may prove to be a
good opportunity to do so.

Thanks,
John

jackie.miller at vaisala.com wrote:
> Hi John,
> 
>  
> 
> To answer your questions:
> 
> *         We will be verifying forecasts for variables at multiple
> levels within the PBL.
> 
> *         Observations are from a range of levels.
> 
>  
> 
> Unfortunately those answers aren't associated with the quick-fix you
> described...(the observation and forecast levels don't match). I will be
> interested to hear what is possible!
> 
>  
> 
> Thanks for your help,
> 
> Jackie  
> 
>  
> 
>  
> 
> Jackie Miller
> 
> Meteorologist
> 
> Vaisala Inc.
> 
>  
> 
> Phone +1 303 885 3251 
> 
> Mobile +1 303 885 3251
> 
> www.vaisala.com
> 
>  
> 
> This electronic message contains a communication which is strictly
> confidential and intended solely for the addressee(s).  Any
> non-addressee is prohibited from reading, disseminating, distributing,
> or copying the communication contained herein.  If you are in possession
> of the communication in error, please immediately notify the sender via
> an electronic response and destroy the original communication.  Thank
> you.
> 
>  
> 
> U.S. Export Restrictions & Disclaimer:  Export of any technical
> information contained in this email and/or its attachments is subject to
> the export control laws and regulations of the U.S. Government and may
> require a valid license or written approval prior to export. 
> 
>  
> 
> -----Original Message-----
> From: John Halley Gotway [mailto:johnhg at ucar.edu] 
> Sent: Wednesday, February 03, 2010 10:32 AM
> To: Miller Jackie JCM
> Cc: met_help at ucar.edu
> Subject: Re: [Met_help] Observation "Level"
> 
>  
> 
> Jackie,
> 
>  
> 
> Thanks for filling out the registration form.  Since you work for
> Vaisala, I assume you'd like to use MET to verify forecasts for wind
> farms.  And you'd like to use observations at 10, 30, and 60m on
> 
> the towers?  Is that correct?
> 
>  
> 
> The logic in the Point-Stat tool (as released in METv2.0) is not
> currently robust enough to do the type of matching you'd like to
> perform.  We had limited the verification of vertical levels to
> 
> 2-meter temperature and 10-meter winds.  However, I think it may only
> take a few lines of code in one of the source file to do what you'd like
> to do.  But I need to ask you a few questions first...
> 
>  
> 
> - What are the level values for the forecasts you're trying to verify?
> Do you have wind forecasts for explicitly 10, 30, and 60 meters above
> ground level?
> 
> - Do you have observations at and want to verify at single levels (10,
> 30, and 60) or a range of levels?  For example, do you ever have
> observations at 58m or 62m, or are they always at 60?
> 
>  
> 
> If the answer is that you have forecasts at single levels (10, 30, and
> 60) and your observations are at those same levels, it should be a very
> easy fix to handle that.  And in that case, I'd have you
> 
> encode your observations as follows:
> 
> - Set "level" to the height of the observation 10, 30, or 60m.
> 
> - Set the message type to ADPSFC.
> 
>  
> 
> The routine we'll need to modify is "add_obs" in the file
> METv2.0/lib/vx_met_util/met_stats.cc.
> 
>  
> 
> And let me suggest that you retrieve the latest set of patches for
> METv2.0, if you haven't already done so:
> 
> http://www.dtcenter.org/met/users/support/known_issues/METv2.0/index.php
> 
> Just follow the instructions at the top of the page to get all of the
> patches.
> 
>  
> 
> Please tell me the answers to those questions, and we can figure out how
> to proceed.
> 
>  
> 
> Thanks,
> 
> John
> 
>  
> 
> jackie.miller at vaisala.com wrote:
> 
>> I am creating ASCII observation files to use with the ASCII2NC tool.
> In
> 
>> the documentation, the ASCII Point Observation Format includes a field
> 
>> called "level" that is "pressure level in hPa or accumulation interval
> 
>> in hours for the observation type".  What is the best way to determine
> 
>> this pressure level?   And does this value vary depending on the
> height
> 
>> of the observation in addition to the elevation? (e.g. will
> measurements
> 
>> taken at 60m, 30m, and 10m on the same tower have different "Level"
> 
>> values?)
> 
> 
>>  
> 
> 
>> Thank you for your help,
> 
> 
>> Jackie
> 
> 
>>  
> 
> 
>> Jackie Miller
> 
>> Meteorologist
> 
> 
>> Vaisala Inc.
> 
> 
>> Phone +1 303 885 3251 
> 
>> Mobile +1 303 885 3251
> 
>> www.vaisala.com
> 
> <https://exchange.ou.edu/owa/redir.aspx?C=b302bd7f7cb24f099b2eb70ba1b9bf
> 
> 5f&URL=https%3a%2f%2fwebmail.vaisala.com%2fexchweb%2fbin%2fredir.asp%3fU
> 
>> RL%3dhttp%3a%2f%2fwww.vaisala.com> 
> 
> 
>>  
> 
> 
>> This electronic message contains a communication which is strictly
> 
>> confidential and intended solely for the addressee(s).  Any
> 
>> non-addressee is prohibited from reading, disseminating, distributing,
> 
>> or copying the communication contained herein.  If you are in
> possession
> 
>> of the communication in error, please immediately notify the sender
> via
> 
>> an electronic response and destroy the original communication.  Thank
> 
>> you.
> 
> 
>>  
> 
> 
>> U.S. Export Restrictions & Disclaimer:  Export of any technical
> 
>> information contained in this email and/or its attachments is subject
> to
> 
>> the export control laws and regulations of the U.S. Government and may
> 
>> require a valid license or written approval prior to export. 
> 
> 
>>  
> 
> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
> 
>> _______________________________________________
> 
>> Met_help mailing list
> 
>> Met_help at mailman.ucar.edu
> 
>> http://mailman.ucar.edu/mailman/listinfo/met_help
> 
> 