Storms from the Sun The Emerging Science of Space Weather (2002) / Chapter Skim
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10. Seasons of the Sun
10. Seasons of the Sun
Pages 153-170
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From page 153... ...
by what causes the rise ant! fall of solar activity.
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It appears that odd-numbered solar cycles tend to be somewhat more intense than even-numbered cycles. And in the past 100 years, solar activity seems to be intensifying compared to the previous century.
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coronal mass ejections are much more common at solar maximum, coronal holes ant! the damaging high-speec!
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of scientists who were charger! with making the best scientific guess at the magnitude of the current solar maximum.
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169, the highest number of the current solar cycle. Living up to the title of "solar maximum," July 2000 brought the Bastille Day storm, a monstrous space weather event that killer!
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Ever since space weather researchers began their media campaign to educate the public about solar maximum, people have been questioning scientists ant! marking their calendars for the day or month of solar maximum.
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the "probability for severe geomagnetic storms will be the greatest cluring an extended period lasting from 1999 through 2005." Even if the Sun floes not follow a scientist's scheclule, even if the storms from the Sun cluring cycle 23 are no worse than any in the past, the current solar maximum ant! the next one in 2011 are expecter!
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Intrigued by the observations and conjectures from eighteenthcentury astronomer William Herschel and nineteenth-century schoolteacher-turned-astronomer Gustav Sporer, Maunder began investigating a phenomenon he would one day call "the prolonged sunspot minimum." Sporer and Herschel both noted that suni6; spots seemed to disappear from the astronomical records for nearly 70 years in the late seventeenth and early eighteenth centuries. As the superintendent of the solar division of Britain's Royal Greenwich Observatory in the 1880s and 1890s, E
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Provokes! by stories that University of Chicago space physicist Gene Parker toicl him about Mauncler, Eclcly reviewocl the turn-of-the-century papers.
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structures of the solar wind can be seen extending for some distance as the Moon blocks the ciazzling clisk of the Sun. Yet at a time when sky watchers wouic!
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. When the Sun is more active, fewer cosmic rays make it into Earth's atmosphere, producing less Ci4; when solar activity is low, cosmic rays flow unimpeclec!
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The Maunder Minimum coincided with a cooling period in many parts of the Earth, and in the 300 years since then, solar activity has steadily increased at the same time as global mean temperatures have increased. But many of the scientists who run computer models of the atmosphere do not seem to have room for the Sun, or at least for one that varies.
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seem that all the spots on the Sun wouic! clim the light a bit, in fact the Sun is brighter cluring solar maximum because there are more bright active regions.
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Observations from UARS show that the additional high-energy radiation at solar maximum increases the amount of ozone in the upper atmosphere by at least 1 or 2 percent. The increase in ozone warms the upper atmosphere, and this warm air affects wind patterns from the stratosphere all the way down to the troposphere (the lower layer of the atmosphere near the surface)
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sunspot minimum such as the Maunder Minimumthe IMF wouic! likely be very weak, allowing more cosmic rays to reach Earth ant!
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Harry van Loon of the National Center for Atmospheric Research have workocl together to show that a known 10- to 12-year oscillation in the stratosphere of the northern ant! southern hemispheres matches up fairly well with the four solar cycles since 1958.
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John Butler of Irelancl's Armagh Observatory fount! that global temperatures seem to fluctuate in synch with the solar cycles.
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Even the most devout Sun-climate researchers acknowledge that it is irresponsible ant! at ocicis with the basic physics of the greenhouse effect to say that inclustrial emissions of carbon clioxicle ant!
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