Perform a localized multitaper spectral analysis using arbitrary windows derived from a mask.
Usage
call SHMultiTaperMaskSE (mtse, sd, cilm, lmax, tapers, lmaxt, k, taper_wt, norm, csphase, exitstatus)
Parameters
mtse: output, real(dp), dimension (lmax-lmaxt+1)- The localized multitaper power spectrum estimate.
sd: output, real(dp), dimension (lmax-lmaxt+1)- The standard error of the localized multitaper power spectral estimates.
cilm: input, real(dp), dimension (2,lmax+1,lmax+1)- The spherical harmonic coefficients of the function to be localized.
lmax: input, integer(int32)- The spherical harmonic bandwidth of
cilm. tapers: input, real(dp), dimension ((lmaxt+1)**2,k)- An array of the
kwindowing functions, arranged in columns, obtained from a call toSHReturnTapersMap. The spherical harmonic coefficients are packed according to the conventions inSHCilmToVector. lmaxt: input, integer(int32)- The spherical harmonic bandwidth of the windowing functions in the array
tapers. k: input, integer(int32)- The number of tapers to be utilized in performing the multitaper spectral analysis.
taper_wt: input, optional, real(dp), dimension (k)- The weights used in calculating the multitaper spectral estimates and standard error. Optimal values of the weights (for a known global power spectrum) can be obtained from the routine
SHMTVarOpt. norm: input, optional, integer(int32), default = 1- 1 (default) = 4-pi (geodesy) normalized harmonics; 2 = Schmidt semi-normalized harmonics; 3 = unnormalized harmonics; 4 = orthonormal harmonics.
csphase: input, optional, integer(int32), default = 1- 1 (default) = do not apply the Condon-Shortley phase factor to the associated Legendre functions; -1 = append the Condon-Shortley phase factor of (-1)^m to the associated Legendre functions.
exitstatus: output, optional, integer(int32)- If present, instead of executing a STOP when an error is encountered, the variable exitstatus will be returned describing the error. 0 = No errors; 1 = Improper dimensions of input array; 2 = Improper bounds for input variable; 3 = Error allocating memory; 4 = File IO error.
Description
SHMultiTaperMaskSE will perform a localized multitaper spectral analysis of an input function expressed in spherical harmonics using an arbitrary set of windows derived from a mask. The maximum degree of the localized multitaper cross-power spectrum estimate is lmax-lmaxt. The matrix tapers contains the spherical harmonic coefficients of the windows and can be obtained by a call to SHReturnTapersMap. The coefficients of each window are stored in a single column, ordered according to the conventions used in SHCilmToVector.
If the optional array taper_wt is specified, these weights will be used in calculating a weighted average of the individual k tapered estimates mtse and the corresponding standard error of the estimates sd. If not present, the weights will all be assumed to be equal. When taper_wt is not specified, the mutltitaper spectral estimate for a given degree will be calculated as the average obtained from the k individual tapered estimates. The standard error of the multitaper estimate at degree l is simply the population standard deviation, S = sqrt(sum (Si - mtse)^2 / (k-1)), divided by sqrt(k). See Wieczorek and Simons (2007) for the relevant expressions when weighted estimates are used.
The employed spherical harmonic normalization and Condon-Shortley phase convention can be set by the optional arguments norm and csphase; if not set, the default is to use geodesy 4-pi normalized harmonics that exclude the Condon-Shortley phase of (-1)^m.
References
Wieczorek, M. A. and F. J. Simons, Minimum-variance multitaper spectral estimation on the sphere, J. Fourier Anal. Appl., 13, doi:10.1007/s00041-006-6904-1, 665-692, 2007.
See also
shmultitapermaskcse, shreturntapersmap, shcilmtovector
Edit me