vmp Month Power (Amplitude) Spectrum

The power spectra is produced with a non-power-of-2 FFT from the time series.

Dimensionally, frequency is along the x-axis, the y-axis contains the order of spherical harmonic, m, from -l to l, and the z-axis contains the power [*,*,1]. The FITS header keyword, CD1_1, gives the conversion factor (microHz/pixels) for the x-axis.

Steps involved: 
1. Calculate the power spectra of a GONG time series image with pseries. 
   lpar pseries 
        input = "@ts"           List of input Time-Series images
       output = "@ps"           List of output Power-spectrum images
 (type_output = "gong")         Output data type (fft|power|gong|rotcor)
         (pad = "none")         Zero padding (none|1st|2nd)
      (debias = yes)            Debias time series prior to FFT
 (use_gapfill = yes)            Used gap-filled data?
    (do_phase = no)             Output phase spectra
      (window = "none")         Window (bartlett|hamming|hanning|parzen|welch|n
     (verbose = yes)            Verbose output
                 
   output 
        mrvmpYYMMDDd[000-200] 
 
   sample FITS header output: 
        GHIST110= 'Task PSERIES (96/06/26 17:51:13, V93.2.31)' 
        GHIST111= 'input=mrvmt960412d235.imh,type_output=gong,window=none,use_gapfi'  
        GHIST112= 'll=yes  ' 
 
   Starting with GONG month 36, rotation-corrected, m-averaged, l-nu spectra were
   generated from separate m-nu power spectra, created by pseries using the 
   type_output="rotcor" option. 
 
2. Write the power spectra to a DSDS tape. 
        tape1 (0<=l<=200)    4.09Gbytes
   Starting with GONG month 36, these products were no longer archived to a 
   DSDS tape. Month l-nu spectra are still produced.

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