Calibrating the Sunspot Number Using "the Magnetic Needle"

Details Calibrating the Sunspot Number Using "the Magnetic Needle" Calibrating the Sunspot Number Using "the Magnetic Needle"

May 2007

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007agusmsh54b..02s&link_type=abstract

American Geophysical Union, Spring Meeting 2007, abstract #SH54B-02

Other

1555 Time Variations: Diurnal To Decadal, 1739 Solar/Planetary Relationships, 2439 Ionospheric Irregularities, 7534 Radio Emissions, 7536 Solar Activity Cycle (2162)

Scientific paper

The 400-year long sunspot series is our primary direct record of Space Climate. Two series exist: the Zurich (now: International) series compiled by Wolf and successors, and the Group series by Hoyt and Schatten. The two series agree well back to ~1875, but before that the Group SSNs are systematically lower than the Wolf SSN. Wolf (and others) noticed that the amplitude, rD, of the daily variation of the Declination of the geomagnetic field varied with the sunspot number, R, and proposed a linear relationship: rD = a + bR. In fact, he used this relationship to calibrate the sunspot number for times before his own observations started (1849). Later researchers were less enthusiastic about this procedure. We re-examine Wolf's relationship using the range of the East component measured in force units [nT], rY, instead. This range is directly related to the intensity of the ionospheric SR currents, which in turn depends on the conductivity of the ionosphere. Solar FUV radiation creates and maintains the ionosphere, therefore the rY range (corrected for the secular decrease of the Earth's main field) is a proxy of the FUV. We show that this proxy reproduces the F10.7 radio flux and the International sunspot number with a correlation coefficient of 0.985, and recalibrate the sunspot number back to 1841 [Geomagnetic data exists that may allow such recalibration back to the 1740s]. The main conclusion is that there does not seem to be any secular increase in solar activity over the last 165 years: cycles 11 and 10 were as active as the most recent cycles 22 and 23.

Affiliated with

Also associated with

No associations

Rating

Calibrating the Sunspot Number Using "the Magnetic Needle" 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 Calibrating the Sunspot Number Using "the Magnetic Needle", we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Calibrating the Sunspot Number Using "the Magnetic Needle" will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1038911