Comparison Of Long-term Trend Of Solar Radius With Sunspot Activity And Flare Index
Abstract
Results are presented from a study of solar radius measurements taken with the solar astrolabe at the TUBITAK National Observatory (TUG) over seven years, 2001-2007. The data series with standard deviation of 0.35 arcsec shows the long-term variational trend with 0.04 arcsec/year. On the other hand, the data series of solar radius are compared with the data of sunspot activity and H-alpha flare index for the same period. Over the seven year trend, we have found significant linear anti-correlations between the solar radius and other indicators such as sunspot numbers, sunspot areas, and H-alpha flare index. While the solar radius displays the strongest anti-correlation (-0.7676) with sunspot numbers, it shows a significant anti-correlation of -0.6365 with sunspot areas. But, the anti-correlation between the solar radius and H-alpha flare index is found to be -0.4975, slightly lower than others. In addition, we computed Hurst exponent of the data sets ranging between 0.7214 and 0.7996, exhibiting the persistent behavior for the long term trend. In the light of the strong correlations with high significance, we may suggest that there are a causal relationship between the solar radius and solar time series such as sunspot activity and H-alpha flare index.
Subject
solar radius
oscillation
sunspot activity
flare index
calern-observatory astrolabe
diameter measurements
ccd astrolabe
cycle dependence
apparent radius
hurst analysis
disk sextant
sun
persistence
irradiance
güneş yarıçapı
salınım
güneş lekesi aktivitesi
parlama indeks
calern-gözlemevi usturlap
çap ölçümleri
ccd usturlap
döngüsü bağımlılığı
belirgin yarıçapı
hurst analizi
Disk sekstant
Güneş
sebat
parlama
oscillation
sunspot activity
flare index
calern-observatory astrolabe
diameter measurements
ccd astrolabe
cycle dependence
apparent radius
hurst analysis
disk sextant
sun
persistence
irradiance
güneş yarıçapı
salınım
güneş lekesi aktivitesi
parlama indeks
calern-gözlemevi usturlap
çap ölçümleri
ccd usturlap
döngüsü bağımlılığı
belirgin yarıçapı
hurst analizi
Disk sekstant
Güneş
sebat
parlama
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