Re: sea level pressure functions pslec and pslhor

Sorry for the delay.

These 'sea level pressure functions' were amongst the 1st
functions included in NCL. The fortran codes were taken directly from a
model post-processor that ran only on NCAR's Cray computers.
They were developed for the CCM [now CAM] hybrid model because,
at that time, the models did not produce a sea level pressure variable.
Use with data sets not from the CCM/CAM models should be done with
caution because users would have to mimic model fields.

[1] pslec: The documentation has been substantially changed.
            See the Example
http://www.ncl.ucar.edu/Document/Functions/Built-in/pslec.shtml

[2] pslhor: The documentation has been substantially changed.
            See the Example
http://www.ncl.ucar.edu/Document/Functions/Built-in/pslhor.shtml

Good luck

On 2/11/14, 1:01 PM, Andy Show wrote:
> Dear NCL users,
>
> I want to calculate the sea level pressure and find three NCL
> functions: pslec, pslhor and pslhyp.
> I have some confusion about the first two pslec and pslhor.
> 1) According to the manual, the argument ps in pslec is a two-dimensional
> array.* S*o, pslec can only be used at one time step, if
> t(time,lev,lat,lon) is a 4-D arry.
> 2) The argument pres in pslec is different from that in pslhor. if pres in
> pslec is the pressure at the lowest vertical level, how is the vertical
> pressure of argument t specified in pslec?
>
> Thank you.
>
> -------------------------------------------------------------------------------------------------------------------------------------------
> *pslec*
>
> *Computes sea level pressure using the ECMWF formulation.*
> *Prototype*
>
> * function pslec (*
> * t : numeric, *
> * phis [*][*] : numeric, *
> * ps [*][*] : numeric, *
> * pres : numeric *
> * )*
>
> * return_val [dimsizes(ps)] : numeric*
> *Arguments*
>
> *t*
> *A multi-dimensional array or scalar value equal to the temperature in K.*
>
> *phis*
> *A two-dimensional array equal to the surface geopotential in m^2/s^2. The
> rightmost two dimensions must be lat and lon.*
>
> *ps*
> *A two-dimensional array equal to the surface pressure in Pa. Must be the
> same size as phis.*
>
> *pres*
> *A multi-dimensional array or scalar value equal to the pressure in Pa.
> Should correspond to the lowest vertical level. Must be at least two
> dimensions. The rightmost two dimensions must be lat and lon.*
> *======================================================================*
> *pslhor*
> *Computes sea level pressure using the ECMWF formulation and Trenberth's
> horizontal correction.*
>
> *Prototype*
>
> * function pslhor (*
> * z : numeric, *
> * t : numeric, *
> * phis [*][*] : numeric, *
> * ps : numeric, *
> * pres : numeric, *
> * lats : numeric *
> * )*
>
> * return_val : numeric*
> *Arguments*
>
> *z*
> *A multi-dimensional array equal to the geopotential height. Must be at
> least three dimensions. The rightmost three dimensions must be level, lat
> and lon. The level dimension must be ordered bottom-to-top.*
>
> *t*
> *A multi-dimensional array equal to the temperature in K. Must be the same
> size as z.*
>
> *phis*
> *A two-dimensional array equal to the surface geopotential in m^2/s^2. The
> rightmost two dimensions must be lat and lon.*
>
> *pres*
> *A multi-dimensional array or scalar value equal to the pressure in Pa.
> Must be the same size as z.*
>
> *ps*
> *A multi-dimensional array equal to the surface pressure in Pa. The
> rightmost three dimensions must be the same size as z.*
>
> *lats*
> *A one-dimensional array equal to latitudes.*
>
> -----------------------------------------------------------------------------------------------------------------------------------
>
>
>
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Received on Thu Feb 27 08:25:05 2014