Polar faculae - 1906-1990
The numbers of faculae at the sun's poles have been estimated from white-light images obtained at the Mount Wilson Observatory during 1970-1990 and have been combined with previous measurements extending back to 1906 when the observations began. The combined measurements now span four complete...
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1991
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ftnasantrs:oai:casi.ntrs.nasa.gov:19910055391 2023-05-15T18:22:35+02:00 Polar faculae - 1906-1990 Sheeley, N. R., Jr. Unclassified, Unlimited, Publicly available Jun 10, 1991 http://ntrs.nasa.gov/search.jsp?R=19910055391 unknown http://ntrs.nasa.gov/search.jsp?R=19910055391 Accession ID: 91A40014 Copyright Other Sources 92 Astrophysical Journal, Part 1; 374; 386-389 1991 ftnasantrs 2012-02-15T19:02:33Z The numbers of faculae at the sun's poles have been estimated from white-light images obtained at the Mount Wilson Observatory during 1970-1990 and have been combined with previous measurements extending back to 1906 when the observations began. The combined measurements now span four complete 22 year cycles and show the following: (1) the numbers of north and south polar faculae were about 50 percent larger around sunspot minimum in 1986 than in 1976, but were still smaller than some of the very large numbers that occurred near sunspot minima in earlier cycles; (2) in 1974, the number of south polar faculae exhibited a short-lived increase which coincided with the arrival of a surge of trailing-polarity flux at the pole, suggesting that similar poleward surges may have been responsible for previously unexplained bursts of faculae such as the one that occurred at the south pole in 1959; and (3) the numbers of polar faculae have been highly correlated with the Wilcox Solar Observatory polar field strengths since these magnetic measurements began in 1976. Other/Unknown Material South pole NASA Technical Reports Server (NTRS) Mount Wilson ENVELOPE(176.250,176.250,-70.583,-70.583) South Pole Wilcox ENVELOPE(-66.933,-66.933,-67.949,-67.949) |
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Open Polar |
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NASA Technical Reports Server (NTRS) |
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ftnasantrs |
language |
unknown |
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92 |
spellingShingle |
92 Sheeley, N. R., Jr. Polar faculae - 1906-1990 |
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92 |
description |
The numbers of faculae at the sun's poles have been estimated from white-light images obtained at the Mount Wilson Observatory during 1970-1990 and have been combined with previous measurements extending back to 1906 when the observations began. The combined measurements now span four complete 22 year cycles and show the following: (1) the numbers of north and south polar faculae were about 50 percent larger around sunspot minimum in 1986 than in 1976, but were still smaller than some of the very large numbers that occurred near sunspot minima in earlier cycles; (2) in 1974, the number of south polar faculae exhibited a short-lived increase which coincided with the arrival of a surge of trailing-polarity flux at the pole, suggesting that similar poleward surges may have been responsible for previously unexplained bursts of faculae such as the one that occurred at the south pole in 1959; and (3) the numbers of polar faculae have been highly correlated with the Wilcox Solar Observatory polar field strengths since these magnetic measurements began in 1976. |
format |
Other/Unknown Material |
author |
Sheeley, N. R., Jr. |
author_facet |
Sheeley, N. R., Jr. |
author_sort |
Sheeley, N. R., Jr. |
title |
Polar faculae - 1906-1990 |
title_short |
Polar faculae - 1906-1990 |
title_full |
Polar faculae - 1906-1990 |
title_fullStr |
Polar faculae - 1906-1990 |
title_full_unstemmed |
Polar faculae - 1906-1990 |
title_sort |
polar faculae - 1906-1990 |
publishDate |
1991 |
url |
http://ntrs.nasa.gov/search.jsp?R=19910055391 |
op_coverage |
Unclassified, Unlimited, Publicly available |
long_lat |
ENVELOPE(176.250,176.250,-70.583,-70.583) ENVELOPE(-66.933,-66.933,-67.949,-67.949) |
geographic |
Mount Wilson South Pole Wilcox |
geographic_facet |
Mount Wilson South Pole Wilcox |
genre |
South pole |
genre_facet |
South pole |
op_source |
Other Sources |
op_relation |
http://ntrs.nasa.gov/search.jsp?R=19910055391 Accession ID: 91A40014 |
op_rights |
Copyright |
_version_ |
1766202001307205632 |