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latRegWgt

Generates [sin(lat+dlat/2)-sin(lat-dlat/2)] weights for equally spaced (regular) global grids that will sum to 2.0.

Available in version 5.1.0 and later.

Prototype

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

	function latRegWgt (
		lat   [*] : numeric,  
		nType [1] : string,   
		opt   [1] : integer   
	)

	return_val [*] :  float

Arguments

lat

Latitudes of global grid [degrees].

nType

Type of variable to be returned [float or double].

opt

Not used. Set to 0.

Return value

A one-dimensional array of same size as lat.

Description

Generates [sin(lat+dlat/2)-sin(lat-dlat/2)] for global grids. The weights will sum to 2.

See Also

latGauWgt, NormCosWgtGlobe, latGau, latGlobeF, latGlobeFo, lonGlobeF, lonGlobeFo, gaus

Examples

The following require that contributed.ncl be loaded prior to invoking the function. 

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

Example 1

Consider a variable lat that spans 87.5S to 87.5N [5 deg spacing]. 

  wgt  = latRegWgt(lat, "double", 0)

  printVarSummary(wgt)
  print(lat+"    "+wgt)
  print("sum(wgt)="+sum(wgt))
The output looks like: 
Variable: wgt
Type: double
Total Size: 288 bytes
            36 values
Number of Dimensions: 1
Dimensions and sizes:   [lat | 36]
Coordinates:
            lat: [-87.5..87.5]
Number Of Attributes: 1
  long_name :   latitude weight

=======
         lat      wgt
(0)     -87.5   0.0038053
(1)     -82.5   0.0113869
(2)     -77.5   0.0188819
[snip]
(16)     -7.5   0.0864924
(17)     -2.5   0.0871557
(18)      2.5   0.0871557
(19)      7.5   0.0864924
[snip]
(33)     77.5   0.0188819
(34)     82.5   0.0113869
(35)     87.5   0.0038053
=======
(0)     sum(wgt)=2
Example 2

Consider a variable lat that spans 90S to 90N [5 deg spacing]. 

  wgt  = latRegWgt(lat, "float", 0)

  printVarSummary(wgt)
  print(lat+"    "+wgt)
  print("sum(wgt)="+sum(wgt))
The edited output looks like: 
Variable: wgt
Type: float
Number of Dimensions: 1
Dimensions and sizes:   [lat | 37]
Coordinates:
            lat: [-90.0..90.0]
Number Of Attributes: 1
  long_name :   latitude weight

=======
         lat      wgt
(0)     -90   0.000951778
(1)     -85   0.00760336
(2)     -80   0.0151489
[snip]
(16)    -10   0.0859134
(17)     -5   0.0869068
(18)      0   0.0872388
(19)      5   0.0869068
(20)     10   0.0859134
[snip]
(34)     80   0.0151489
(35)     85   0.00760336
(36)     90   0.000951778
=======
(0)     sum(wgt)=2