Radio Imaging Observations of Solar Activity Cycle and Its Anomaly

Details Radio Imaging Observations of Solar Activity Cycle and Its Anomaly Radio Imaging Observations of Solar Activity Cycle and Its Anomaly

Dec 2011

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufmsh33a2035s&link_type=abstract

American Geophysical Union, Fall Meeting 2011, abstract #SH33A-2035

Astronomy and Astrophysics

Astrophysics

[7534] Solar Physics, Astrophysics, And Astronomy / Radio Emissions, [7536] Solar Physics, Astrophysics, And Astronomy / Solar Activity Cycle

Scientific paper

The 24th solar activity cycle has started and relative sunspot numbers are increasing. However, their rate of increase is rather slow compared to previous cycles. Active region sizes are small, lifetime is short, and big (X-class) flares are rare so far. We study this anomalous situation using data from Nobeyama Radioheliograph (NoRH). Radio imaging observations have been done by NoRH since 1992. Nearly 20 years of daily radio images of the Sun at 17 GHz are used to synthesize a radio butterfly diagram. Due to stable operation of the instrument and a robust calibration method, uniform datasets are available covering the whole period of observation. The radio butterfly diagram shows bright features corresponding to active region belts and their migration toward low latitude as the solar cycle progresses. In the present solar activity cycle (24), increase of radio brightness is delayed and slow. There are also bright features around both poles (polar brightening). Their brightness show solar cycle dependence but peaks around solar minimum. Comparison between the last minimum and the previous one shows decrease of its brightness. This corresponds to weakening of polar magnetic field activity between them. In the northern pole, polar brightening is already weakened in 2011, which means it is close to solar maximum in the northern hemisphere. Southern pole does not show such feature yet. Slow rise of activity in active region belt, weakening of polar activity during the minimum, and large north-south asymmetry in polar activity imply that global solar activity and its synchronization are weakening.

Affiliated with

Also associated with

No associations

Rating

Radio Imaging Observations of Solar Activity Cycle and Its Anomaly does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Radio Imaging Observations of Solar Activity Cycle and Its Anomaly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radio Imaging Observations of Solar Activity Cycle and Its Anomaly will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-878877