Re: Spaghetti Plots of 564dm

From: Adam Phillips <asphilli_at_nyahnyahspammersnyahnyah>
Date: Mon, 22 Jun 2009 14:29:42 -0600

Hi Bruce,

Lunde, Bruce N CIV NAVOCEANO, NP1 wrote:
> Hello,
> I am looking at
> the the example "tigge_2.ncl"
> I had a few basic questions of what it is doing.
> (I am trying to make a spaghetti plot from a set of
> separate netcdf files.)
> In your example, all of the ensemble data (for all levels)
> is contained in one grib file.

You can use addfiles
to read in all your files at once if desired.

> You load all the data, then pull out one level (one
> pressure level at 500hPa) for all the ensemble
> members.
> You then find the contour of the 564dm reading.
> 1) Is this correct ?

Yes. In the mres resource list the resource cnLevels is set to 564. So
NCL is told to only draw the 564dm contour.

> 2) Could you refresh me on what the "564dm" refers to ?

I'm not sure whether TIGGE geopotential height data is distributed in
units of geopotential meters or simply meters. (Divide geopotential
meters by gravity to get meters.) I'll assume the former. The 564dm
contour refers to where the 500hPa pressure surface is 564 geopotential
dekameters above sea level. I see that a comment in example 2 refers to
it as decimeters. That is incorrect, it should say dekameters.
Best regards,

> Thanks, Bruce
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Adam Phillips			   
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Received on Mon Jun 22 2009 - 14:29:42 MDT

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