Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (57) (Citation History)
· Refereed Citations to the Article
· Reads History
·
· Translate This Page
Title:
Evolution of the 155 day periodicity in sunspot areas during solar cycles 12 to 21
Authors:
Lean, Judith
Affiliation:
AA(U.S. Navy, E. O. Hulburt Center for Space Research, Washington, DC)
Publication:
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 363, Nov. 10, 1990, p. 718-727. (ApJ Homepage)
Publication Date:
11/1990
Category:
Solar Physics
Origin:
STI
NASA/STI Keywords:
SOLAR CYCLES, SUNSPOTS, EVOLUTION (DEVELOPMENT), H ALPHA LINE, SOLAR FLARES, TIME SERIES ANALYSIS
DOI:
10.1086/169378
Bibliographic Code:
1990ApJ...363..718L

Abstract

Sunspot area data during solar cycles 12-21 are examined with both periodogram and evolutionary spectral analysis techniques for evidence of a periodicity near 155 days. This periodicity is found to be present only during epochs of maxium activity, when it modulates the sunspot areas by as much as 15-20 percent of the amplitude of the 11 yr cycle. The 155 day periodicity typically occurs in episodes of from 1 to 3 yr, with sequential episodes often in opposite solar hemispheres; the strengths of these episodes appear to track the general level of solar activity. Comparing the phases of sinusoids fitted to the sunspot area data within individual solar cycles provides evidence for coherency within + or - 8 days of a period at 155 days between solar cycles 19, 20, and 21. However, within any one episode the actual period of the 155 day cycle may drift from 130 to 185 days.

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences


More Article Retrieval Options

HELP for Article Retrieval
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
  New!

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints