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[Datastream #MZN-388937]: lightning data, td9603

Hi Nancy,

re:
> We started ingesting lightning data from the LDM feed.  The data will be
> used for research purposes only).

What is the upstream feeder for your LIGHTNING data?

re:
> After decoding, we seem to be getting
> some bad amplitude values.
> 
> The date, lat and long, the two flags and the multiplicity seem to be fine.
> 
> The amplitude goes from about -650 to about +650, but according to the
> documentation Should go from about -254 to +254.

Which documentation indicates that the range should be -254 - 254?  Can I assume
that you are referring to documents from Vaisala?

re:
> We are using:
> 
> kiloamp = int (signl/10.0) / 150.0 ) *30 to decode amplitude   (values +/- 
> 650)
> deciseconds= int (nsec / 100.0)
> 
> to decode microsec to nanosec  (values, 0-90 by 10)
> 
> Does this look correct?

The meaning of the comment "150 NLDN measures ~= 30 kAmps" has never been
very clear to me/us.  In our "documentation" for NLDN data:

http://www.unidata.ucar.edu/data/lightning/nldn.html

I interpret 'sgnl' as an "NLDN measure".  Dividing this number
by 150 would, if this interpretation is correct, give the number
of 30 kAmps.

If you divide the range of values that you report above (-650 - 650)
by 30 (i.e., undo the product you introduce in your formula), and
multiply by 10 (i.e., not divide the "measure" by 10), your range
becomes -216 - 216 which falls in the range specified in Vaisala
documentation.

We will have to contact folks at UAlbany to get their "expert"
interpretation of the meaning of "150 NLDN measures ~= 30 kAmps"
(this is straight out of inline source code documentation).

re:

Sorry we can't be more definitive!

Cheers,

Tom
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Ticket Details
===================
Ticket ID: MZN-388937
Department: Support Datastream
Priority: Normal
Status: Closed