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Re: 20030528: IDV questions - pressure grid from other grid
- Subject: Re: 20030528: IDV questions - pressure grid from other grid
- Date: Fri, 06 Jun 2003 10:35:47 -0600
Charlie,
> 1. I'm doing a calculation of kinetic energy using
> the u and v wind fields from the ETA model,
> but I need to calculate the air density and for that I need
> the temperature which is no problem but also the pressure.
> Is there any way to access pressure value of an isobaric
> surface to include it as a variable in the calculation?
use this Jython method.
def extractPressureFromNWPGrid(fieldimpl):
"""get pressure coordinate grid from a VisAD FieldImpl
(a time series of one or more FlatFields);
user must be sure input is a suitable FlatField. """
#import methods from ucar code
from ucar.unidata.data.grid.DerivedGridFactory import *
#import FlatField and FieldImpl class from visad code
from visad.FlatField import *
from visad.FieldImpl import *
# get the first grid from the FieldImpl
ff = fieldimpl.getSample(0)
return DerivedGridFactory.createPressureGridFromDomain(ff)
The input grid "fieldimpl" can be any model output grid from
say Eta or RUC that has the grid x-y-pressure structure you are using.
It could be the same grid you get temperature from.
Stu
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