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obj_anal_ic_Wrap

Iterative improvement objective analysis and returns meta data.

Available in version 5.2.0 and later.

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"

	function obj_anal_ic_Wrap (
		zlon   [*] : numeric,  
		zlat   [*] : numeric,  
		z          : numeric,  
		glon   [*] : numeric,  
		glat   [*] : numeric,  
		rscan  [*] : numeric,  
		option [1] : logical   
	)

Arguments

zlon
zlat

One-dimensional arrays containing the longitudes and latitudes associated with the z values. They must be the same length as the rightmost dimension of z.

z

An array, whose rightmost dimension is the same length as zlon and zlat, containing the values associated with the zlon and zlat coordinates. Missing values, indicated via z@_FillValue, may be present but will be ignored.

glon

A one-dimensional array of length M containing the longitude coordinates associated with the returned two-dimensional grid.

glat

A one-dimensional array of length N containing the latitude coordinates associated with the returned two-dimensional grid.

rscan

A one-dimensional array of length K specifying the successive radii of influence. The maximum size of rscan is 10. Typically, rscan contains one-to-four elements. Must be expressed in degrees of latitude and must be monotonically decreasing. eg: rscan = (/10, 5, 3/)

option

If option=False, this function will operate under default mode. If option=True, then this variable may have associated with it the attribute blend_wgt. This specifies how successive new estimates are 'blended'(local smoother) with previously derived estimates. These values must be 0.0 < blend_wgt < 1.0. A value of 1.0 means that the current interpolated value will be used. Otherwise:

      new_value(n) = blend_wgt(n)*current_estimate + (1-blend_wgt(n))*value(n-1)
The size of blend_wgt must be the same size as rscan.

Return value

If z is one dimensional,the return array be N x M; if multidimensional the return array will be K x N x M, where K represents the leftmost dimensions of z. It will be of type double if z is double, and float otherwise.

Description

This performs an iterative improvement type objective analysis using an input triplet set ( zlon, zlat, z). For each gridpoint, multiple passes of descending radii of influence are used to obtain better estimates.

Note: It is possible that some returned grid points could be _FillValue. If this is not desired, increase the radii of incluence.

See Also

obj_anal_ic, cssgrid, cssgrid_Wrap, natgrid, natgrid_Wrap, triple2grid, triple2grid2d

Examples

Example 1

Assume zlon, zlat and zVal are one-dimensional (1D) arrays; let lon and lat be 1D arrays specifying grid locations. Then:

   rscan = (/10, 5, 2/)
   grid = obj_anal_ic(zlon,zlat,zVal, lon,lat, rscan, False)

will use default behavior and return a 2D array of size N x M M.

Example 2

Let zVal be a two-dimensional array of size (T,KPTS). Let lon and lat be 1D arrays of lengths N and M specifying grid locations. Then:

   rscan = (/20, 12.5, 7.5/)
   grid = obj_anal_ic_Wrap(xlon,ylat,zVal, lon,lat, False)        ; grid(T,N,M)

will use default behavior and return a 3D array of size T x N x M.

Example 3

   rscan         = (/20, 10, 5/)
   opt           = True          
   opt@blend_wgt = (/1.0, 0.5, 0.25/)
   grid = obj_anal_ic_Wrap(xlon,ylat,zVal, lon,lat, opt)