On Short-Term Periodicity Of The Solar Radius Measurements
Abstract
The aim of the present study is to investigate the short-term periodicity in the solar radius measurements and to compare with the short periods in sunspot numbers, sunspot areas and flare index data. The spectral analysis of data sets covering a time interval from 26 February 2000 to 26 October 2007 during Solar Cycle 23 were made by using the Date Compensated Discrete Fourier Transform (DCDFT). The power spectrum of solar radius data corrected for the seeing effect gives an evident peak at 25.7 days with the amplitude of 0.034 arcsec, which is slightly different from the peaks of 26.2 and 26.7 days produced by sunspot numbers and sunspot areas data, respectively. Besides, the main peak of 25.7 days detected in the power spectrum of solar radius data is in agreement with the period of 25.5 days, suggested to be the fundamental period of the Sun by Bai and Sturrock (in Nature 350, 141, 1991).
Subject
solar radius
sunspot activity
flare index
short periodicities
calern-observatory astrolabe
diameter measurements
ccd astrolabe
flare index
time-series
spectral-analysis
disk sextant
solar-cycle-23
variability
constancy
güneş yarıçapı
güneş lekesi aktivitesi
parlama indeks
calern-gözlemevi usturlap
çap ölçümleri
ccd usturlap
parlama indeks
Zaman serisi
spektral analiz
Disk sekstant
Güneş döngüsü-23
değişkenlik
sabitlik
sunspot activity
flare index
short periodicities
calern-observatory astrolabe
diameter measurements
ccd astrolabe
flare index
time-series
spectral-analysis
disk sextant
solar-cycle-23
variability
constancy
güneş yarıçapı
güneş lekesi aktivitesi
parlama indeks
calern-gözlemevi usturlap
çap ölçümleri
ccd usturlap
parlama indeks
Zaman serisi
spektral analiz
Disk sekstant
Güneş döngüsü-23
değişkenlik
sabitlik
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