NASA Revises Cycle 24 Sunspot Prediction.


David Hathaway, NASA solar cycle expert, has a revised forecast for Solar Cycle 24 Sunspot number and Maximum timing.  In May 2012, he forecast the smoothed sunspot number maximum at 60 and the timing of the maximum as the spring of 2013.  His January 2013 Cycle 24  revised forecast is for 69 spots and maximum in the Fall of 2013.  He adds:
“ We are currently over four years into Cycle 24. The current predicted and observed size makes this the smallest sunspot cycle since Cycle 14 which had a maximum of 64.2 in February of 1906.”  
 jan13hathawayssn_predict
       Hathaway’s  NASA Revised January 2013 Sunspot Number Prediction
 
I defer to Hathaway, of course, but the month of December 2012 seems to be in opposition to his latest forecast. Note that the following charts are by NOAA/SWPC.(Click on charts to improve clarity.)
 dec12sunspot
The F10.7 cm flux number also took a header. For reference, Hathaway’s description of F10.7 is as follows:
“Another indicator of the level of solar activity is the flux of radio emission from the Sun at a wavelength of 10.7 cm (2.8 GHz frequency). This flux has been measured daily since 1947. It is an important indicator of solar activity because it tends to follow the changes in the solar ultraviolet that influence the Earth’s upper atmosphere and ionosphere. Many models of the upper atmosphere use the 10.7 cm flux (F10.7) as input to determine atmospheric densities and satellite drag. F10.7 has been shown to follow the sunspot number quite closely and similar prediction techniques can be used.”
 dec12f10
The geomagnetic field that is a proxy for solar activity and it also dropped.
dec12Ap
The knowledge the experts have regarding the Sun is advancing quickly, but the forces that motivate the changes are not nearly as well understood. So, we can but wait and see what the Sun will actually do.
cbdakota
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