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mjo_cross_segment

Calculate space-time cross spectrum for a single time segment.

Prototype

	function mjo_cross_segment (
		x [*][*][*] : numeric,  
		y [*][*][*] : numeric,  
		opt     [1] : integer   
	)

	return_val  :

Arguments

x
y

Three dimensional variable arrays which nominally are dimensioned: (time,lat,lon).
The longitudes should be global while the latitudes should only span the south-north region of interest. The size of the 'time' dimension should be the size of the desired segment length. EG: for daily mean data, the size of the time dimension is typically 96, 128, 256, etc.

opt

Currently, not used. Set to 0.

Return value

The return variable will be a three-dimensional array (16,wavenumber,frequency) containing the 16 cross spectral quantities associated with the specific time segment.

         ( 0,:,:)  -  symmetric power spectrum of x
         ( 1,:,:)  -  asymmetric power spectrum of x
         ( 2,:,:)  -  symmetric power spectrum of y
         ( 3,:,:)  -  asymmetric power spectrum of y
         ( 4,:,:)  -  symmetric cospectrum 
         ( 5,:,:)  -  asymmetric cospectrum 
         ( 6,:,:)  -  symmetric quadrature spectrum 
         ( 7,:,:)  -  asymmetric quadrature spectrum 
         ( 8,:,:)  -  symmetric coherence-squared spectrum 
         ( 9,:,:)  -  asymmetric coherence-squared spectrum 
         (10,:,:)  -  symmetric phase spectrum 
         (11,:,:)  -  asymmetric phase spectrum 
         (12,:,:)  -  symmetric component-1 phase spectrum 
         (13,:,:)  -  asymmetric component-1 phase spectrum 
         (14,:,:)  -  symmetric component-2 phase spectrum 
         (15,:,:)  -  asymmetric component-2 phase spectrum

The coordinate frequencies span 0.0 to 0.5. The coordinate wavenumbers span -M/2 to M/2 where M is the number of longitudes.

Description

See the Level 2 diagnostics description titled MULTI-SCALE INTERACTIONS at the US-CLIVAR MJO diagnostics website

Examples