[Met_help] Observation "Level"

[John Halley Gotway]

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
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> 
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