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[IDV #OFJ-761065]: ECMWF model levels

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  • Subject: [IDV #OFJ-761065]: ECMWF model levels
  • Date: Thu, 20 Dec 2007 08:27:42 -0700
Hi HP-

> I note that IDV now can display correctly grib-coded fields at ECMWF
> model levels (thanks!). Unfortunately, At ECMWF model level only
> specific humidity can be retrieved as WV variable, i.e. no Sounding Data
> display is derived. Questions:
> 
> 1. Has somebody implemented conversion from specific to relative humidty
> resp. dew-point temperature?

Not that I know of.  You could post the question to idvusers and
see if anyone there has worked on it.  Otherwise, I'll put it on
the "TODO" list.

> 2. In absence of the required relative humidity or dew-point would it
> still be possible to introduce the display of T-windsoundings only using
> the model levels as linear scale (ECMWF levels are numbered 0-91 from
> top to bottom!).

This would be difficult at present.  The whole sounding control
needs major revamping, and is very specific to having data on
pressure levels.

> 3. Even better for soundings would be to replace the level scale with
> pressure. How would one access the level variable in a Jython module?

What is the relation of pressure to model level? Is it location
dependent or just a lookup table?

Doing the replacement in Jython would be a bit cumbersome and since
there are CoordinateSystems involved, you'd need a low level 
understanding of the VisAD data structure to create the new
domain.  It even makes my head hurt.

Don


Ticket Details
===================
Ticket ID: OFJ-761065
Department: Support IDV
Priority: Normal
Status: Open