[Wrf-users] Confused about model height

[sparling at umbc.edu]

Also,if you do a line plot of elevation vs lat (or lon) and overplot the
geopotential height of the lowest model level and you can see that it
follows the topography.
Cheers,

Lynn

> Hello John,
>
> Geopotential heights are always given as height above sea level (I think
> the definition is more rigorous than this, but the effects of the
> non-spherical earth and non-uniform gravitiational fields are second-order
> effects). Otherwise, if height fields were computed as the height above
> the ground level, height fields would be distorted by the pattern of
> surface topography, and could not be used for calculating geostrophic
> winds, for example.
>
> Best regards,
>
> Eric L. Altshuler
> Assistant Research Scientist
> Center for Ocean-Land-Atmosphere Studies
> 4041 Powder Mill Road, Suite 302
> Calverton, MD 20705-3106
> USA
>
> E-mail: ela at cola.iges.org
> Phone: (301) 902-1257
> Fax: (301) 595-9793
>
> ----- Original Message -----
> From: "John Krasting" <krasting at envsci.rutgers.edu>
> To: wrf-users at ucar.edu, "WRF Help" <wrfhelp at ucar.edu>
> Sent: Tuesday, March 10, 2009 3:01:14 PM GMT -05:00 US/Canada Eastern
> Subject: [Wrf-users] Confused about model height
>
> Hi Users -
>
> Just want to confirm exactly how height is calculated using ARWpost.
>
> Is this the height above ground level or above sea level?  I'm
> assuming that since WRF is using a terrain-following hydrostatic
> coordinate, that these values are above ground level.
>
>
> Thanks,
> John
>
> -----------------------------
>
> more module_calc_height.f90
> !! Diagnostics: Height
>
> MODULE module_calc_height
>
>   CONTAINS
>   SUBROUTINE calc_height(SCR, cname, cdesc, cunits)
>
>   USE constants_module
>   USE module_model_basics
>
>   !Arguments
>   real, pointer, dimension(:,:,:)       :: SCR
>   character (len=128)                   :: cname, cdesc, cunits
>
>
>   SCR      = ( (PH+PHB) / G ) / 1000.
>   cname    = "height"
>   cdesc    = "Model height"
>   cunits   = "KM"
>
>   END SUBROUTINE calc_height
>
> END MODULE module_calc_height
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>



^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Lynn Sparling			sparling at umbc.edu
Associate Professor		PH:   410-455-6231
Department of Physics		FAX: 410-455-1072
University of Maryland, Baltimore County
1000 Hilltop Circle
Baltimore, MD 21250

"One can measure to test the ruler." -Wittgenstein