Cycle 24 November 2011 Update

November Cycle 24 monthly sunspot count was nearly 100, which is by far the most active period since the cycle began.    The same goes for the F 10.7 Radio Flux that racked up a value of about 155.  But of these numbers are well below those of Cycle 23 at its peak.  Cycle 23 peak sunspot count was 170 and its F10.7 was about 235.   See the  November NOAA/SWPC charts below:


Solar Activity/Geomagnetism

The Ap index is a good proxy for overall solar activity. For two months it has declined.  We are seeing Cycle 24 peaks in F10.7, and sunspots simultaneously with this drop in Ap.  It may mean that the spots and F10.7 may soon be trending downward as well.

If you  are interested,  the following is a brief explanation of the various ways geomagnetism is expressed.

The magnetic activity indices K, Kp and ap are designed to measure the variations in the geomagnetic field that arise from current systems caused by regular solar radiation changes. Other irregular current systems produce magnetic field changes caused by the interaction of the solar wind with the magnetosphere, by the magnetosphere itself, by the interactions between the magnetosphere and ionosphere, and by the ionosphere itself.

The planetary 3-hour range index Kp is the mean K-index from 13 geomagnetic observatories.  The scale is 0 to 9 expressed in thirds of a unit, 5-  is 4 2/3, 5 is 5 and 5+ is 5 1/3.  This planetary index is designed to measure particle radiation by its magnetic effects.  The 3-hourly ap (equivalent range) index is derive from the Kp index as follows:

Kp = 0o   0+   1-   1o   1+   2-   2o   2+   3-   3o   3+   4-   4o   4+

ap =  0     2     3      4     5     6     7       9    12   15    18     22   27   32

Kp = 5-    5o    5+   6-   6o    6+    7-     7o     7+     8-     8o     8+    9-     9o

ap = 39   48   56    67   80   94   111  132    154   179   207  236  300  400

Now one more derivation to get to the Ap index.   The  Ap index is defined as the earliest occurring maximum 24-hour value  obtained by computing an 8-point running average of successive 3-hour ap indices during a geomagnetic storm event.


2 responses to “Cycle 24 November 2011 Update

  1. I’m looking for the latest butterfly graph. The latest I can find is

    Thanks for the other data and analysis.

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