The Acrim Data in the Context of Stellar Variability
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Reconstruction of Solar EUV Flux 1840-2014
Reconstruction of Solar Extreme Ultraviolet Flux 1740–2015 Leif Svalgaard1 ([email protected]) 1 Stanford University, Cypress Hall C13, W.W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA Abstract: Solar Extreme Ultraviolet (EUV) radiation creates the conducting E–layer of the ionosphere, mainly by photo ionization of molecular Oxygen. Solar heating of the ionosphere creates thermal winds which by dynamo action induce an electric field driving an electric current having a magnetic effect observable on the ground, as was discovered by G. Graham in 1722. The current rises and sets with the Sun and thus causes a readily observable diurnal variation of the geomagnetic field, allowing us the deduce the conductivity and thus the EUV flux as far back as reliable magnetic data reach. High– quality data go back to the ‘Magnetic Crusade’ of the 1830s and less reliable, but still usable, data are available for portions of the hundred years before that. J.R. Wolf and, independently, J.–A. Gautier discovered the dependence of the diurnal variation on solar activity, and today we understand and can invert that relationship to construct a reliable record of the EUV flux from the geomagnetic record. We compare that to the F10.7 flux and the sunspot number, and find that the reconstructed EUV flux reproduces the F10.7 flux with great accuracy. On the other hand, it appears that the Relative Sunspot Number as currently defined is beginning to no longer be a faithful representation of solar magnetic activity, at least as measured by the EUV and related indices. -
Effects of the Solar Cycles and Longer-Term
University of New Hampshire University of New Hampshire Scholars' Repository Doctoral Dissertations Student Scholarship Summer 2019 Effects of the Solar Cycles and Longer-Term Solar Variations: Modulation of Galactic Cosmic Radiation and Filtration of Neutral Atoms from the Local Interstellar Medium Fatemeh Rahmanifard University of New Hampshire, Durham Follow this and additional works at: https://scholars.unh.edu/dissertation Recommended Citation Rahmanifard, Fatemeh, "Effects of the Solar Cycles and Longer-Term Solar Variations: Modulation of Galactic Cosmic Radiation and Filtration of Neutral Atoms from the Local Interstellar Medium" (2019). Doctoral Dissertations. 2483. https://scholars.unh.edu/dissertation/2483 This Dissertation is brought to you for free and open access by the Student Scholarship at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. Effects of the Solar Cycles and Longer-Term Solar Variations: Modulation of Galactic Cosmic Radiation and Filtration of Neutral Atoms from the Local Interstellar Medium BY Fatemeh Rahmanifard B.Sc., Amirkabir University of Technology, 2007 M.Sc., Amirkabir University of Technology, 2011 THESIS Submitted to the University of New Hampshire in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Physics September, 2019 ALL RIGHTS RESERVED c Year My Name ii This thesis has been examined and approved in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physics by: Thesis Director, Dr. Nathan Schwadron, Presidential Chair, Norman S. and Anna Marie Waite Physics Professor Dr. -
Analysing the Spotless Days As Predictors of the Solar Activity From
Analysing the spotless days as predictors of the solar activity from the new sunspot number V.M.S. Carrasco1,2 • J.M. Vaquero3,4 • M.C. Gallego2,3 1 Centros de Estudios Energéticos y Radiofísicos, Badajoz, Spain 2 Departamento de Física, Universidad de Extremadura, Badajoz, Spain 3 Departamento de Física, Universidad de Extremadura, Mérida (Badajoz), Spain 4 Instituto Universitario de Investigación del Agua, Cambio Climático y Sostenibilidad (IACYS), Universidad de Extremadura, Badajoz, Spain Abstract. The use of the spotless days to predict the future solar activity is here revised based on the new version of the sunspot number index with a 24-month filter. Data from Solar Cycle (SC) 10 are considered because from this solar cycle the temporal coverage of the records is 100 %. The interrelationships of the timing characteristics of spotless days and their comparison with sunspot cycle parameters are explored, in some cases finding very strong correlations. Such is the case for the relationship between the minimum time between spotless days either side of a given solar maximum and the maximum time between spotless days either side in the previous solar minimum, with r = -0.91 and a p-value < 0.001. However, the predictions for SC 24 or 23 made by other authors in previous works using the spotless days as a predictor of solar activity are not good since it has not been fulfilled. Although there seems to be a pattern of strong correlation for some relationships between the parameters studied, prediction of future solar cycles from these parameters defined as functions of the spotless days should be made with caution because sometimes the estimated values are far from the observed 1 ones. -
What Can the Annual 10Be Solar Activity Reconstructions Tell Us About Historic Space Weather?
J. Space Weather Space Clim. 2018, 8, A23 © L. Barnard et al., Published by EDP Sciences 2018 https://doi.org/10.1051/swsc/2018014 Available online at: www.swsc-journal.org RESEARCH ARTICLE What can the annual 10Be solar activity reconstructions tell us about historic space weather? Luke Barnard1,*, Ken G. McCracken2, Mat J. Owens1 and Mike Lockwood1 1 Department of Meteorology, University of Reading, Reading, UK 2 100 Mt. Jellore Lane, Woodlands, 2575, Australia Received 11 August 2017 / Accepted 20 February 2018 Abstract – Context: Cosmogenic isotopes provide useful estimates of past solar magnetic activity, constraining past space climate with reasonable uncertainty. Much less is known about past space weather conditions. Recent advances in the analysis of 10Be by McCracken & Beer (2015, Sol Phys 290: 305–3069) (MB15) suggest that annually resolved 10Be can be significantly affected by solar energetic particle (SEP) fluxes. This poses a problem, and presents an opportunity, as the accurate quantification of past solar magnetic activity requires the SEP effects to be determined and isolated, whilst doing so might provide a valuable record of past SEP fluxes. Aims: We compare the MB15 reconstruction of the heliospheric magnetic field (HMF), with two independent estimates of the HMF derived from sunspot records and geomagnetic variability. We aim to quantify the differences between the HMF reconstructions, and speculate on the origin of these differences. We test whether the differences between the reconstructions appear to depend on known significant space weather events. Methods: We analyse the distributions of the differences between the HMF reconstructions. We consider how the differences vary as a function of solar cycle phase, and, using a Kolmogorov-Smirnov test, we compare the distributions under the two conditions of whether or not large space weather events were known to have occurred. -
Arxiv:2105.11448V2 [Astro-Ph.SR] 25 May 2021 1 INTRODUCTION
Research in Astron. Astrophys. Vol.0 (20xx) No.0, 000–000 Research in http://www.raa-journal.org http://www.iop.org/journals/raa Astronomy and (LATEX: main.tex; printed on May 26, 2021; 0:23) Astrophysics Spotless days and geomagnetic index as the predictors of solar cycle 25 Dipali S. Burud1;9, Rajmal Jain2, Arun K. Awasthi3;4, Sneha Chaudhari9, Sushanta C. Tripathy5, N. Gopalswamy6, Pramod Chamadia7, Subhash C. Kaushik8 and Rajiv Vhatkar1 1 Department of Physics, Shivaji University, Kolhapur, India 2 Physical Research Laboratory, Navrangpura, 380009 Ahmedabad; [email protected] 3 CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026, China 4 CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Beijing 100101, China 5 National Solar Observatory, 3665 Discovery Drive, Boulder, CO 80303, United States 6 Goddard Space Flight Centre, NASA, Washington, USA 7 Department of Physics, Govt. P. G. College, Satna, M. P., India, 8 Department of Physics, Govt. PG Autonomous College, Datiya, M. P, India 9 Sh. M. M. Patel Institute of Sciences and Research, Kadi Sarva Vishwavidyalaya, Gandhinagar, India Received 20xx month day; accepted 20xx month day Abstract We study the sunspot activity in relation to spotless days (SLDs) during the descending phase of solar cycle 11–24 to predict the amplitude of sunspot cycle 25. For this purpose, in addition to SLD, we also use the geomagnetic activity (aa index) during the descending phase of a given cycle. A very strong correlation of the SLD (R=0:68) and aa index (R=0:86) during the descending phase of a given cycle with the maximum amplitude of next solar cycle has been estimated.The empirical relationship led us to deduce the amplitude of cycle 25 to be 99.13± 14.97 and 104.23± 17.35 using SLD and aa index, respectively as predictors.Both the predictors provide comparable amplitude for solar cycle 25 and reveal that the solar cycle 25 will be weaker than cycle 24. -
The Role of the Sun in Climate Change
The Role of the Sun in Climate Change Douglas V. Hoyt Kenneth H. Schatten Oxford University Press The ROLE of the SUN in CLIMATE CHANGE THE SUN ON JULY 6, 1979. FROM W. J. LIVINGSTON. The ROLE of the SUN in CLIMATE CHANGE Douglas V Hoyt Kenneth H. Schatten New York Oxford • Oxford University Press 1997 Oxford University Press Oxford New York Athens Auckland Bangkok Bogota Bombay Buenos Aires Calcutta Cape Town Dar es Salaam Delhi Florence Hong Kong Istanbul Karachi Kuala Lumpur Madras Madrid Melbourne Mexico City Nairobi Paris Singapore Taipei Tokyo Toronto and associated companies in Berlin Ibadan Copyright © 1997 by Oxford University Press, Inc. Published by Oxford University Press, Inc., 198 Madison Avenue, New York, New York 10016 Oxford is a registered trademark of Oxford University Press All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. Library of Congress Cataloging-in-Publication Data Hoyt, Douglas V. The role of the sun in climate change / Douglas V. Hoyt, Kenneth H. Schalten. p. cm. Includes bibliographical references and index. 1SBN 0-19-509413-1; ISBN 0-19-509414-X (pbk.) 1. Solar activity. 2. Climatic changes. I. Schatten, Kenneth H. II. Title. QC883.2.S6H69 1997 551.6—dc20 96-10848 987654321 Printed in the United States of America on acid-free paper Acknowledgments We would like to thank Tom Bryant, Richard A. Goldberg, and O. R. White for reviewing a draft of this book.