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20001009: PVOR

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  • Subject: 20001009: PVOR
  • Date: Tue, 10 Oct 2000 13:25:16 -0600
Pat,

$GEMPAKHOME/source/gemlib/dv/dvpvor.f:

C* DV_PVOR                                                              *
C*                                                                      *
C* This subroutine computes the potential vorticity in a layer from     *
C* scalar (thermal and pressure) and vector (wind) fields:              *
C*                                                                      *
C*     PVOR ( s, V ) = - GRAVTY * AVOR ( VLAV (V) ) * LDF ( CTA ) /     *
C*                  ( 100 * LDF ( PRES ) )                              *
C*                                                                      *
C*                  Where: 100 converts millibars to Pascals            *
C*                         CTA can be THTA, THTE, or THES               *
C*                                                                      *
C* PVOR works on a layer in THTA or PRES coordinates.  In the case of   *
C* PRES, the vorticity of the layer averaged wind is corrected by       *
C* the addition of ( k cross partial V w.r.t. CTA ) dot grad (CTA).     *
C* PVOR generates a scalar grid.

Steve Chiswell
Unidata User Support



>From: address@hidden
>Organization: UCAR/Unidata
>Keywords: 200010101815.e9AIFJ429846

>Steve:
>
>I guess what I'm asking is:  Is PVOR still formulated as the k hat component
>of the full equation?
>
>I was told that by using PVOR(THES,GEO) that this got me an EPV
>of the full 3-d form
>
>     EPV = -eta  dot  del(Theta_e)
>
>where eta is the total vorticity, and the del is a 3-d operator.
>
>Nowhere in my reading of the documentation does it say this.  
>
>Has there been a contribution, perhaps that does this?
>
>Thanks.
>
>Pat
>
>> 
>> >From: address@hidden
>> >Organization: UCAR/Unidata
>> >Keywords: 200010091702.e99H2b428162
>> 
>> >
>> >Hello.
>> >
>> >I am told that by using PVOR(THES, GEO) that this now yields a 3-d
>> >value for EPV.  Is this so?
>> >
>> >We are running GEMPAK5.4, patch level 14.
>> >
>> >Thanks.
>> >
>> >Pat
>> >-- 
>> >=======================================================================
>> >Dr. Patrick S. Market                           Phone: (573) 882 - 1496
>> >University of Missouri-Columbia                   Lab: (573) 882 - 6372
>> >Soil and Atmospheric Sciences                     Fax: (573) 884 - 5133
>> >203 Gentry Hall                    e-mail:  address@hidden
>> >Columbia, MO  65211              Web:  http://web.missouri.edu/~marketp
>> >=======================================================================
>> >
>> 
>> 
>> Patrick,
>> 
>> As defined in the GEMPAK User Guide under GPARM, PVOR() is a layer quantity.
>> If you are looking at a grid cross section in gdcross, then the layer 
>> quantities are computed automatically: 
>>  GVCORD   = pres
>>  GFUNC    = pvor(thes,geo)
>> 
>> If you are using a plan view such as with gdcntr, then glevel should
>> represent the layer over which you want the calculation to occur.
>> 
>> Steve Chiswell
>> ****************************************************************************
>> Unidata User Support                                    UCAR Unidata Program
>> (303)497-8644                                                  P.O. Box 3000
>> address@hidden                                   Boulder, CO 80307
>> ----------------------------------------------------------------------------
>> Unidata WWW Service                        http://www.unidata.ucar.edu/     
>> ****************************************************************************
>> 
>
>
>-- 
>=======================================================================
>Dr. Patrick S. Market                           Phone: (573) 882 - 1496
>University of Missouri-Columbia                   Lab: (573) 882 - 6372
>Soil and Atmospheric Sciences                     Fax: (573) 884 - 5133
>203 Gentry Hall                    e-mail:  address@hidden
>Columbia, MO  65211              Web:  http://web.missouri.edu/~marketp
>=======================================================================
>