Re: [noaaport] Question about lifted index product

• To: Gary Lucas <gwlucas@xxxxxxxxxxxxx>
• Subject: Re: [noaaport] Question about lifted index product
• From: Mike Zuranski <zuranski@xxxxxxxxxxxxxxx>
• Date: Tue, 26 Sep 2017 13:07:38 -0500

Hi Gary,

As you stated, LI is a difference product so it's expected to have
both positive and negative values.  Because TempC = TempK - 273.15,
the difference between the parcel temperature and the environment
temperature will be the same in Celsius or kelvin.  Since kelvin is
the SI base unit for temperature, I believe that's why it's the unit
for the LI product here.  But since it's a difference product, you
don't need to do any conversion, you can just plot it can call it
Celsius.

Hope this helps,

-Mike

======================
Mike Zuranski
Meteorology Support Analyst
College of DuPage - Nexlab
Weather.cod.edu
======================


On Tue, Sep 26, 2017 at 12:50 PM, Gary Lucas <gwlucas@xxxxxxxxxxxxx> wrote:
> I’m looking at some of the new GOES-16 derived products being distributed
> via NOAAport and I have a question.   Looking at the ABI L2+ Derived
> Stability Indices: Lifted Index products, I am seeing the temperatures given
> with units=”K”  (Kelvin), but some of the data values are in the negative
> range.
>
>
>
> Because lifted index is given as a temperature difference, I believe that
> the units field of the data is being incorrectly populated and should
> probably be “C”.   Is anyone else seeing this?
>
>
>
> Is there somebody I can contact about this issue?
>
>
>
> Gary
>
>
>
> Here’s the dump from the raw data.
>
>
>
>
>
> target0.sectorizedCMI = (ucar.nc2.Variable) short LI(y=100, x=100);
>
>   :_FillValue = -1S; // short
>
>   :long_name = "ABI L2+ Derived Stability Indices: Lifted Index";
>
>   :standard_name =
> "temperature_difference_between_ambient_air_and_air_lifted_adiabatically_from_the_surface";
>
>   :_Unsigned = "true";
>
>   :valid_range = 0S, -6S; // short
>
>   :scale_factor = 7.6301E-4f; // float
>
>   :add_offset = -10.0f; // float
>
>   :units = "K";
>
>   :resolution = "y: 0.000280 rad x: 0.000280 rad";
>
>   :coordinates = "latitude retrieval_local_zenith_angle
> quantitative_local_zenith_angle solar_zenith_angle t y x
> final_air_pressure";
>
>   :grid_mapping = "goes_imager_projection";
>
>   :cell_methods = "latitude: point (good quality pixel produced)
> retrieval_local_zenith_angle: point (good or degraded quality pixel
> produced) quantitative_local_zenith_angle: point (good quality pixel
> produced) solar_zenith_angle: point (good quality pixel produced) t: point
> area: point";
>
>   :ancillary_variables = "DQF_Overall DQF_Retrieval DQF_SkinTemp";
>
>   :_ChunkSizes = 100, 100; // int
>
>
>
> Gary W. Lucas, Senior Software Engineer
>
> Sonalysts, Inc.
>
> 215 Parkway North
>
> Waterford, CT 06385
>
> (860) 326-3682
>
> 41-22-12.35 N / 72-10-07.54 W  (USNG/MGRS:  18T YL 36787 83711)
>
>
>
>
>
>
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• References:
  • [noaaport] Question about lifted index product
    • From: Gary Lucas