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vintp2p_ecmwf

Interpolates data at multidimensional pressure levels to constant pressure coordinates and uses an ECMWF formulation to extrapolate values below ground.

Prototype

	function vintp2p_ecmwf (
		datai      : numeric,  
		presi      : numeric,  
		plevo  [*] : numeric,  
		psfc       : numeric,  
		intyp  [1] : integer,  
		ii     [1] : integer,  
		kxtrp  [1] : logical,  
		varflg [1] : integer,  
		tbot       : numeric,  
		phis       : numeric   
	)

	return_val  :  numeric

Arguments

datai

An array of at most *five* dimensions. The order of the dimensions is specific. The three right-most dimensions must be level,lat,lon [e.g. TS(time,lev,lat,lon) or TS(case,time,lev,lat,lon)]. The order of the level dimension must be top-to-bottom.

presi

An array with the same dimensions as datai containing the pressures [hPa] at each grid point. The order of the level dimension must be top-to-bottom.

plevo

A one-dimensional array of output pressure levels in mb.

psfc

A multi-dimensional array of surface pressures in Pa. Must have the same dimension sizes as the corresponding dimensions of datai.

intyp

Scalar integer value equal to the interpolation type 1 - LINEAR, 2 - LOG, 3 - LOG LOG

ii

Not used at this time. Set to 1.

kxtrp

Logical. False = no extrapolation when the pressure level is outside of the range of psfc.

varflg

A scalar integer indicating which variable to interpolate: 1 = temperature, -1 = geopotential height, 0 = all others.

tbot

A multi-dimensional array the same sizes as psfc equal to temperature at the lowest (i.e, closest to the surface) level. While this is used only if varflg=-1 (ie, geopotential height), it must still be provided for all cases.

phis

A multi-dimensional array of surface geopotential (m^2/sec) in which the rightmost two dimensions are the same as psfc.

Return value

A multi-dimensional array of the same size as datai except that the level coordinate has been replaced by plevo. The function automatically copies the metadata from datai to return_val.

The type of the output data will be double only if psfc and datai are of type double. Otherwise, the return type will be float.

See Also

vinth2p, vinth2p_ecmwf

Examples

Example 1

  fccm = addfile ("dummy.nc" , "r")  
  PSFC = f->PS
  P0mb = 0.01*f->P0
  PHIS = f->PHIS                       ; surface geopotential [2D]

  PRESI= f->PRESI                   
  T    = f->T                          ; temperature at pressure levels
  Z    = f->Z3                         ; geo hgt at hybrid levels
  U    = f->U                          ; zonal wind
  
  tbot = T(:,nlev-1,:,:)               ; bot temp level [clarity]
 
  nlev = dimsizes(hyam)                ; number of vertical levels
                                       ; specify levels to be interpolated
  lev_p   = (/ 850., 700., 500., 300., 200. /)
  lev_p!0         = "lev_p"            ; variable and dimension name the same
  lev_p&lev_p     = lev_p              ; create coordinate variable
  lev_p@long_name = "pressure"         ; attach some attributes
  lev_p@units     = "hPa"
  lev_p@positive  = "down"
  
  intyp = 1                             ; 1=linear, 2=log, 3=log-log
  kxtrp = True                          ; True=extrapolate
  
  varflg = 1                           ; temperature is variable
  Tp     = vintp2p_ecmwf(T, PRESI,lev_p,PSFC,intyp,P0mb, \
                 1,kxtrp,varflg,tbot,PHIS)
  varflg = -1                          ; geo pot hgt is variable [tbot is used]
  Zp     = vintp2p_ecmwf(Z, PRESI, lev_p ,PSFC, intyp, P0mb, \
                 1,kxtrp,varflg,tbot,PHIS)
  varflg = 0                           ; not T or Z
  Up     = vintp2p_ecmwf(U,PRESI,lev_p,PSFC,intyp,P0mb,\
                 1,kxtrp,varflg,tbot,PHIS)