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dim_avg_wgt_Wrap

Computes the weighted average of a variable's rightmost dimension at all other dimensions and retains metadata.

Available in version 4.2.0.a034 and later.

Prototype

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

	function dim_avg_wgt_Wrap (
		x       : numeric,  
		w   [*] : numeric,  
		opt [1] : integer   
	)

	return_val  :  float or double

Arguments

x

A variable of numeric type and any dimensionality. Missing values are indicated by the _FillValue attribute.

w

A one dimensional of weights. The length must the same as the right dimension of x.

opt

A scalar: (a) opt=0 means compute the weighted average only if all values are not missing; (b) opt=1 means compute the weighted mean of all non-missing values; (c) opt>1 means to return the mean only if the number of non-missing values is greater-than or equal to opt.

Return value

The output will be double if x is double, and float otherwise.

The output dimensionality is the same as the first n-2 dimensions of the input variable. That is, the dimension rank of the input variable will be reduced by one.

Description

Computes the weighted average of all elements of the n-1th (rightmost) dimension for each index of the dimensions 0...n-2 and retains metadata. A wrapper function.

Use dim_avg_wgt_n_Wrap if you want to specify which dimension to do the average across.

See Also

dim_avg_wgt, dim_avg_wgt_n_Wrap, avg, dim_median, dim_stddev, dim_num, dim_product, dim_rmsd, dim_rmvmean, dim_rmvmed, dim_standardize, dim_stat4, dim_stddev, dim_sum, dim_variance

Examples

Example 1

Let z(12,nlat,mlon) contain monthly means and with named dimensions "time", "lat" and "lon", respectively. Compute the weighted annual mean at each lat/lon point. Use dimension reordering to make time the rightmost dimension. 

    wgt = (/0.08493151, 0.076712325, 0.08493151, 0.08219178 \ ; same size as dimension "lev" 
           ,0.08493151, 0.08219178 , 0.08493151, 0.08493151 \
           ,0.08219178, 0.08493151 , 0.08219178, 0.08493151 /)                            
 
    zAnn = dim_avg_wgt_Wrap( z(lat|:,lon|:,time|:), wgt, 0 )    ; ==> zAnn(lat,lon)

    zAnn = dim_avg_wgt_n_Wrap( z, wgt, 0, 0 )    ; no reordering needed
All attributes and, if present, latitude and longitude coordinate variables are retained.

Note: in V5.1.1, you will be able to use dim_avg_wgt_n_Wrap to avoid having to reorder your data.

Example 2

Let T(time,lev,lat,lon). Compute the weighted vertical average total at each time/lat/lon point. Use dimension reordering to make level the rightmost dimension. 

    delp = (/50,50,100,100,100,50,25,10/)  ; same size as dimension "time"

    Tavg = dim_avg_wgt_Wrap( T(time|:,lat|:,lon|:,lev|:), wgt, 0 )    ; ==> Tavg(time,lat,lon) 

    Tavg = dim_avg_wgt_n_Wrap( T, wgt, 0, 1 )                         ; no reordering needed