| An Estimate of the Size and Shape of Sunspot Cycle 24 Based on its Early Cycle Behavior using the Hathaway-Wilson-Reichmann Shape-Fitting Function Contributor(s): Administration (Nasa), National Aeronaut (Author) |
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ISBN: ISBN-13: 9798672753768 Publisher: Independently Published OUR PRICE: $31.49 Product Type: Paperback Published: August 2020 * Not available - Not in print at this time * |
| Additional Information |
| BISAC Categories: - Science | Space Science |
| Physical Information: 0.07" H x 8.5" W x 11.02" (0.24 lbs) 36 pages |
| Descriptions, Reviews, Etc. |
| Publisher Description: On the basis of 12-month moving averages (12-mma) of monthly mean sunspot number (R), sunspot cycle 24 had its minimum amplitude (Rm = 1.7) in December 2008. At 12 mo past minimum, R measured 8.3, and at 18 mo past minimum, it measured 16.4. Thus far, the maximum month-to-month rate of rise in 12-mma values of monthly mean sunspot number (AR(t) max) has been 1.7, having occurred at elapsed times past minimum amplitude (t) of 14 and 15 mo. Compared to other sunspot cycles of the modern era, cycle 24's Rm and AR(t) max (as observed so far) are the smallest on record, suggesting that it likely will be a slow-rising, long-period sunspot cycle of below average maximum amplitude (RM). Supporting this view is the now observed relative strength of cycle 24's geomagnetic minimum amplitude as measured using the 12-mma value of the aa-geomagnetic index (aam = 8.4), which also is the smallest on record, having occurred at t equals 8 and 9 mo. From the method of Ohl (the inferred preferential association between RM and aam), one predicts RM = 55 +/- 17 (the ?1 se prediction interval) for cycle 24. Furthermore, from the Waldmeier effect (the inferred preferential association between the ascent duration (ASC) and RM) one predicts an ASC longer than 48 mo for cycle 24; hence, maximum amplitude occurrence should be after December 2012. Application of the Hathaway-Wilson-Reichmann shape-fitting function, using an RM = 70 and ASC = 56 mo, is found to adequately fit the early sunspot number growth of cycle 24. Wilson, Robert M. Marshall Space Flight Center NASA/TP-2011-216461, M-1310 SUNSPOTS; SUNSPOT CYCLE; SHAPE FUNCTIONS; GEOMAGNETISM; ASCENT; FITTING; SHAPES |