Anticorrelation between changes of Hα spectral line FWHM and Doppler velocities

From September the 25 th , 2012 through October 17, 18 and 19, 2012, new series of Hα spicule spectrograms for 7,500 km heights in the solar chromosphere were obtained by using a 53-cm large non-eclipsing coronagraph of Abastumani Astrophysical Observatory (Georgia). Spectrograms in Hα line were obtained in a second series of the spectrograph, where reversed dispersion equaled to 0.96 Å/mm. Doppler velocities and half-widths of 10 spicules were measured with the cadence of 4.5 sec and standard error equals to ±0.3 km/sec and 0.03 Å. Life times of almost all measured spicules were 12-16 min. Therefore, they resemble the type I spicules.To study and find periodical changes of Hα FWHM, we used the Lomb periodogram algorithm for unevenly distributed time series. We also processed Doppler velocities using the same algorithm for the same spicules in the same images. The confidence levels for our data equaled to 9.0 for 95% and 10.7 for 99% in power units. The periods are mostly above 2 min (> 180 sec). Most periods fall between 5-9 min (300-540 sec). In order to see the possible relations between the changes of Hα FWHM and Doppler velocities, we performed Low Pass FFT Filtering with different cut-off frequencies: 60 sec (0.016 Hz), 100 sec (0.01 Hz) and 200 sec (0.005 Hz). All 10 spicules show clearly anticorreleation properties, especially for the longest periodical changes.