Long-term Solar Activity Studies using Microwave Imaging Observations and Prediction for Cycle 25

Abstract

We use microwave imaging observations from the Nobeyama Radioheliograph at 17 GHz for long-term studies of solar activity. In particular, we use the polar and low-latitude brightness temperatures as proxies to the polar magnetic field and the active-regions, respectively. We also use the location of prominence eruptions as a proxy to the filament locations as a function of time. We show that the polar microwave brightness temperature is highly correlated with the polar magnetic field strength and the fast solar wind speed. We also show that the polar microwave brightness at one cycle is correlated with the low latitude brightness with a lag of about half a solar cycle. We use this correlation to predict the strength of the solar cycle: the smoothed sunspot numbers in the southern and northern hemispheres can be predicted as 89 and 59, respectively. These values indicate that cycle 25 will not be too different from cycle 24 in its strength. We also combined the rush to the pole data from Nobeyama prominences with historical data going back to 1860 to study the north-south asymmetry of sign reversal at solar poles. We find that the reversal asymmetry has a quasi-periodicity of 3-5 cycles.

21 pages, 10 figures, 1 table, accepted for publication on April 07, 2018 in Journal of Atmospheric and Solar-Terrestrial Physics

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Cited by in corpus (18)

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• Long-term Variations in Solar Activity: Predictions for Amplitude and North--South Asymmetry of Solar Cycle 25
• Effect of the Weakened Heliosphere in Solar Cycle 24 on the Properties of Coronal Mass Ejections
• Another Mini Solar Maximum in the Offing: A Prediction for the Amplitude of Solar Cycle 25
• Collective Study of Polar Crown Filaments in the Past Four Solar Cycles
• Effect of morphological asymmetry between leading and following sunspots on the prediction of solar cycle activity
• Solar Activity and Space Weather
• North-South Asymmetry in Solar Activity and Solar Cycle Prediction, V: Prediction for the North-South Asymmetry in the Amplitude of Solar Cycle 25
• Spotless days and geomagnetic index as the predictors of solar cycle 25
• A new tool for predicting the solar cycle: Correlation between flux transport at the equator and the poles
• Occurrence rate of radio-loud and halo CMEs in solar cycle 25: Prediction using their correlation with sunspot numbers
• Comparative Study of Microwave Polar Brightening, Coronal Holes, and Solar Wind Over the Solar Poles
• Solar cycle activity: an early prediction for cycle #25
• Coronal mass ejections as a new indicator of the active Sun
• Solar Cycle Prediction: Challenges, Progress, and Future Perspectives