[gradsusr] Lapse Rates

[Jeff Duda]

Daniel,
I used arbitrary names for the height field. Use 'q file' to check to see
what the actual name is for the height field in your data (if it even
exists). Also, check for syntax errors. It looks like I missed a ')' at the
end of the command.

Jeff

On Fri, Nov 14, 2014 at 2:05 AM, Daniel Nairn <dannairn at gmail.com> wrote:

> Thanks Jeff, I wasn't convinced that my original formula was going to be
> that accurate.  I've updated my script, as you suggested, for the 700-500
> lapse rates however the images generated are now blank? The script
> completes without any errors. If I revert back to my original script then
> the images are produced as expected.
>
>
>
> On 13 November 2014 22:59, Jeff Duda <jeffduda319 at gmail.com> wrote:
>
>> It would be more accurate if you used the actual height fields at the
>> pressure levels instead of assuming a fixed height difference.  In other
>> words, try
>>
>> 'define LR75 = (tmpprs(lev=500)-tmpprs(lev=700)) /
>> (hgtprs(lev=500)-hgtprs(lev=700)'
>>
>> for 700-500 mb lapse rates. Note how I flipped the order of the
>> subtraction from your formula. You'll want to use delta_T = T_upper -
>> T_lower when computing lapse rates.
>>
>> 0-3 km lapse rates can be difficult if you only have isobaric fields.
>> There are scripts in the script library to interpolate isobaric fields to
>> constant height fields. If you don't need high accuracy, subbing in a
>> pressure level that is close to 3 km works. Depending on the time of year,
>> usually 700 mb is pretty close, but keep in mind that people usually use
>> 0-3 km ABOVE GROUND LEVEL lapse rates, so in areas of high elevation, 700
>> mb will be far less than 3 km above ground.
>>
>> Jeff Duda
>>
>> On Thu, Nov 13, 2014 at 3:53 PM, Daniel Nairn <dannairn at gmail.com> wrote:
>>
>>> Hi
>>>
>>> Could somebody please help verify my two GrAds scripts for displaying
>>> Lapse Rates? I have created two individual scripts, one for displaying
>>> 700-500mb lapse rates and the other for displaying 0-3km lapse rates, they
>>> are as follows:-
>>>
>>> 0-3 Script
>>> 'define temp = ((tmpprs(lev=1000)-tmpprs(lev=700))/2.5908)'
>>>
>>> 700-500 Script
>>> 'define temp = ((tmpprs(lev=700)-tmpprs(lev=500))/2.5908)'
>>>
>>> They work and seem to verify against other sources but they have been
>>> pieced together form many Google searches and I'm a little unsure if they
>>> are accurate/correct :-)
>>>
>>> Thank you
>>>
>>>
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>>>
>>
>>
>> --
>> Jeff Duda
>> Graduate research assistant
>> University of Oklahoma School of Meteorology
>> Center for Analysis and Prediction of Storms
>>
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>>
>
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-- 
Jeff Duda
Graduate research assistant
University of Oklahoma School of Meteorology
Center for Analysis and Prediction of Storms
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