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pres_sigma

Calculates the pressure at specified sigma levels.

Prototype

	function pres_sigma (
		sigma [*] : numeric,  
		ps        : numeric   
	)

	return_val  :  numeric

Arguments

sigma

A one-dimensional array equal to the sigma levels (length nsigma).

ps

At least a two-dimensional array equal to the surface pressure. The rightmost two dimensions must be latitude x longitude (nlat x nlon).

Return value

A multi-dimensional array of dimensions N x nsigma x nlat x nlon where N represents all but the rightmost two dimensions of ps. The return type will be double if ps is double, and float otherwise.

Description

Calculates the pressure at specified sigma levels.

Examples

Example 1

Assume ps is a two-dimensional array of with dimensions lat,lon. pSigma will be a as a three-dimensional array with dimensions level, lat, and lon. The size of the level dimension is the same size as sigma.

 
  pSigma = pres_sigma (sigma, ps)   ; pSigma(klvl,nlat,mlon)
Example 2

Assume ps is a three-dimensional array with dimensions time,lat,lon. pSigma will be a four-dimensional array with dimensions time, level, lat, and lon. The size of the level dimension is the same size as sigma.

  pSigma = pres_sigma (sigma, ps)   ; pSigma(ntim,klvl,nlat,mlon)
Example 3

The same as example 1, but calculated in a loop (this method is not recommended because loops are inefficient):

  do nt=0,ntim-1
    p = pres_sigma (sigma, psfc(nt,:,:))   ; ==> p(lev,lat,lon)
       :
       :
  end do