[ncl-talk] RUC2-Analysis Data Incorrectly Interpolated to Surface

[Dennis Shea]

A key is  the 'level_type' attribute associated with the pressure variables
(PRES_). There are numerous PRES_ variables. In particular,

      float PRES_P0_L1_GLC0 ( ygrid_0, xgrid_0 )
         center :       US National Weather Service - NCEP (WMC)
         production_status :    Operational products
         long_name :    Pressure
         units :        Pa
         _FillValue :   1e+20
         coordinates :  gridlat_0 gridlon_0
         grid_type :    Lambert Conformal can be secant or tangent, conical
or bipolar
         parameter_discipline_and_category :    Meteorological products,
Mass
         parameter_template_discipline_category_number :        ( 0, 0, 3,
0 )
         level_type :   Ground or water surface
<*******************************************
         level :         0
         forecast_time :        0
         forecast_time_units :  hours
         initial_time : 06/05/2009 (12:00)

It is a guess that this is the surface pressure (psfc). All pressure levels
> psfc must be extrapolated. [ *Extrapolation is always dangerous!]

The 'ind' function can be used to get all 'valid' levels [ p<psfc ]. Try
attached.

Cheers


On Thu, Jan 28, 2016 at 11:47 AM, Michelle Serino <mmserino at tamu.edu> wrote:

> Good afternoon,
>
> I am plotting RUC2-Analysis data on a skew-T.  Because this is analysis
> data, it seems that the data are always interpolated to the 1000-mb
> surface, regardless of the chosen location.  For example, in a high
> elevation location like Denver, the data extend down to 1000 mb, which is
> unrealistic.  This creates incorrect surface values, which results in a
> very incorrect value of surface CAPE.
>
> I am wondering if, while still plotting on a skew-T, there is a way to
> specify the data that is plotted.  Or, if there is another, more realistic,
> way around this.  With a real sounding, I would not have this problem, so I
> am sure there is a way to fix this for the analysis data.  I have attached
> the script I am using, along with its plot and an observed sounding for the
> same location (Denver).  The direct link to the analysis data I am using is
> provided below.  I appreciate any help!
>
>
> https://www.dropbox.com/s/qpe96hmhh9hsi0h/ruc2anl_130_20090605_1200_000.grb2?dl=0
>
> Best regards,
>
> Michelle Serino
>
> Michelle Serino
> M.S. Candidate
> Texas A&M University
> Atmospheric Sciences Dept.
> Eller O&M, Suite 1017
> College Station, TX 77843
> (484) 769-0949
>
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