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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