[ncl-talk] Problem with calculation of wet bulb temperature

[Barry Lynn]

Bill:

Thanks.

For the moment, I just limited the pressure to below a value that seems to
work.  No one (here) cares about the Wet Bulb Temperature over the Dead Sea.

Still, it would be nice to have it work as is, so I should take a look.

Barry

On Tue, Aug 28, 2018 at 8:09 PM Bill Ladwig <ladwig at ucar.edu> wrote:

> Hi Barry,
>
> Modifying the table isn't easy, but if you like to live dangerously, I can
> show you where the file is.
>
> When NCL is installed, the file is installed here:
>
> $NCARG_ROOT/lib/ncarg/data/asc/psadilookup.dat
>
>
> For the source code, it is located here:
>
> {NCL_SOURCE_ROOT}/ni/src/examples/data/asc/psadilookup.dat
>
>
> There is a brief description at the top of the file that explains how to
> read the data in Fortran, but it should give you some idea of how you might
> modify the values. As long as you keep the dimensions the same (e.g. 150 x
> 150), then you can probably shift the table in to your region of interest.
> The table is read in when the wetbulb and CAPE algorithms are run, so you
> shouldn't have to change anything but the table.  You probably want to make
> a copy of this file and store it somewhere else before modifying the values.
>
> Unfortunately, I don't think we have the original code that generated the
> table, so you're probably on your own implementing the algorithm from
> Bolton. But, it might be buried in the RIP source code somewhere, which is
> where the algorithm originally came from.
>
> Hope this helps,
>
> Bill
>
>
> On Tue, Aug 28, 2018 at 5:39 AM Barry Lynn <barry.h.lynn at gmail.com> wrote:
>
>> Hi:
>>
>> I live in an area t aht has locations 200 to 400 m below sea-level.
>>
>> When calling:
>>
>> twb = wrf_wetbulb(p,t,qv)
>>
>>
>> I get this error:
>>
>>
>> Outside of lookup table bounds. prs,thte=   1100.3168750000000        347.73405695443734
>>
>>
>>
>> So, is it possible to expand the lookup table or to return the closest
>> value?
>>
>>
>> Thanks Barry
>>
>>
>>
>>
>> --
>> Barry H. Lynn, Ph.D
>> Senior Associate Scientist, Lecturer,
>> The Institute of the Earth Science,
>> The Hebrew University of Jerusalem,
>> Givat Ram, Jerusalem 91904, Israel
>> Tel: 972 547 231 170
>> Fax: (972)-25662581
>>
>> C.E.O, Weather It Is, LTD
>> Weather and Climate Focus
>> http://weather-it-is.com
>> Jerusalem, Israel
>> Local: 02 930 9525
>> Cell: 054 7 231 170
>> Int-IS: x972 2 930 9525
>>
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>

-- 
Barry H. Lynn, Ph.D
Senior Associate Scientist, Lecturer,
The Institute of the Earth Science,
The Hebrew University of Jerusalem,
Givat Ram, Jerusalem 91904, Israel
Tel: 972 547 231 170
Fax: (972)-25662581

C.E.O, Weather It Is, LTD
Weather and Climate Focus
http://weather-it-is.com
Jerusalem, Israel
Local: 02 930 9525
Cell: 054 7 231 170
Int-IS: x972 2 930 9525
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