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Title: CALIBRATING 100 YEARS OF POLAR FACULAE MEASUREMENTS: IMPLICATIONS FOR THE EVOLUTION OF THE HELIOSPHERIC MAGNETIC FIELD

Abstract

Although the Sun's polar magnetic fields are thought to provide important clues for understanding the 11 year sunspot cycle, including the observed variations of its amplitude and period, the current database of high-quality polar field measurements spans relatively few sunspot cycles. In this paper, we address this deficiency by consolidating Mount Wilson Observatory polar faculae data from four data reduction campaigns, validating it through a comparison with facular data counted automatically from Michelson Doppler Imager (MDI) intensitygrams, and calibrating it against polar field measurements taken by the Wilcox Solar Observatory and average polar field and total polar flux calculated using MDI line-of-sight magnetograms. Our results show that the consolidated polar facular measurements are in excellent agreement with both polar field and polar flux estimates, making them an ideal proxy to study the evolution of the polar magnetic field. Additionally, we combine this database with sunspot area measurements to study the role of the polar magnetic flux in the evolution of the heliospheric magnetic field (HMF). We find that there is a strong correlation between HMF and polar flux at solar minimum and that, taken together, polar flux and sunspot area are better at explaining the evolution of the HMF duringmore » the last century than sunspot area alone.« less

Authors:
;  [1];  [2];  [3]
  1. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
  2. Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States)
  3. School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030 (United States)
Publication Date:
OSTI Identifier:
22039392
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 753; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COMPARATIVE EVALUATIONS; CORRELATIONS; FACULAE; MAGNETIC FIELDS; MAGNETIC FLUX; MAGNETISM; PLAGES; SUN; SUNSPOTS; SURFACES; VARIATIONS

Citation Formats

Munoz-Jaramillo, Andres, DeLuca, Edward E, Sheeley, Neil R, and Zhang, Jie. CALIBRATING 100 YEARS OF POLAR FACULAE MEASUREMENTS: IMPLICATIONS FOR THE EVOLUTION OF THE HELIOSPHERIC MAGNETIC FIELD. United States: N. p., 2012. Web. doi:10.1088/0004-637X/753/2/146.
Munoz-Jaramillo, Andres, DeLuca, Edward E, Sheeley, Neil R, & Zhang, Jie. CALIBRATING 100 YEARS OF POLAR FACULAE MEASUREMENTS: IMPLICATIONS FOR THE EVOLUTION OF THE HELIOSPHERIC MAGNETIC FIELD. United States. https://doi.org/10.1088/0004-637X/753/2/146
Munoz-Jaramillo, Andres, DeLuca, Edward E, Sheeley, Neil R, and Zhang, Jie. 2012. "CALIBRATING 100 YEARS OF POLAR FACULAE MEASUREMENTS: IMPLICATIONS FOR THE EVOLUTION OF THE HELIOSPHERIC MAGNETIC FIELD". United States. https://doi.org/10.1088/0004-637X/753/2/146.
@article{osti_22039392,
title = {CALIBRATING 100 YEARS OF POLAR FACULAE MEASUREMENTS: IMPLICATIONS FOR THE EVOLUTION OF THE HELIOSPHERIC MAGNETIC FIELD},
author = {Munoz-Jaramillo, Andres and DeLuca, Edward E and Sheeley, Neil R and Zhang, Jie},
abstractNote = {Although the Sun's polar magnetic fields are thought to provide important clues for understanding the 11 year sunspot cycle, including the observed variations of its amplitude and period, the current database of high-quality polar field measurements spans relatively few sunspot cycles. In this paper, we address this deficiency by consolidating Mount Wilson Observatory polar faculae data from four data reduction campaigns, validating it through a comparison with facular data counted automatically from Michelson Doppler Imager (MDI) intensitygrams, and calibrating it against polar field measurements taken by the Wilcox Solar Observatory and average polar field and total polar flux calculated using MDI line-of-sight magnetograms. Our results show that the consolidated polar facular measurements are in excellent agreement with both polar field and polar flux estimates, making them an ideal proxy to study the evolution of the polar magnetic field. Additionally, we combine this database with sunspot area measurements to study the role of the polar magnetic flux in the evolution of the heliospheric magnetic field (HMF). We find that there is a strong correlation between HMF and polar flux at solar minimum and that, taken together, polar flux and sunspot area are better at explaining the evolution of the HMF during the last century than sunspot area alone.},
doi = {10.1088/0004-637X/753/2/146},
url = {https://www.osti.gov/biblio/22039392}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 753,
place = {United States},
year = {Tue Jul 10 00:00:00 EDT 2012},
month = {Tue Jul 10 00:00:00 EDT 2012}
}