A Caltech Library Service

Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?

Love, Jeffrey J. and Mursula, Kalevi and Tsai, Victor C. and Perkins, David M. (2011) Are secular correlations between sunspots, geomagnetic activity, and global temperature significant? Geophysical Research Letters, 38 (21). Art. No. L21703. ISSN 0094-8276. doi:10.1029/2011GL049380.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


Recent studies have led to speculation that solar-terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross-correlations between sunspot number, geomagnetic activity, and global surface temperature for the years 1868–2008, solar cycles 11–23. The data contain substantial autocorrelation and nonstationarity, properties that are incompatible with standard measures of cross-correlational significance, but which can be largely removed by averaging over solar cycles and first-difference detrending. Treated data show an expected statistically-significant correlation between sunspot number and geomagnetic activity, Pearson p < 10^(−4), but correlations between global temperature and sunspot number (geomagnetic activity) are not significant, p = 0.9954, (p = 0.8171). In other words, straightforward analysis does not support widely-cited suggestions that these data record a prominent role for solar-terrestrial interaction in global climate change. With respect to the sunspot-number, geomagnetic-activity, and global-temperature data, three alternative hypotheses remain difficult to reject: (1) the role of solar-terrestrial interaction in recent climate change is contained wholly in long-term trends and not in any shorter-term secular variation, or, (2) an anthropogenic signal is hiding correlation between solar-terrestrial variables and global temperature, or, (3) the null hypothesis, recent climate change has not been influenced by solar-terrestrial interaction.

Item Type:Article
Related URLs:
URLURL TypeDescription
Tsai, Victor C.0000-0003-1809-6672
Additional Information:© 2011 by the American Geophysical Union. Received 19 August 2011; accepted 12 October 2011; published 11 November 2011. We thank E. W. Cliver, V. Courtillot, C. A. Finn, J. L. Gannon, J. W. Godt, E. J. Rigler, and an anonymous reviewer for reviewing a draft manuscript. K. Mursula acknowledges financial support from the Academy of Finland, projects 128189 and 131350. [17] The Editor thanks two anonymous reviewers for their assistance in evaluating this paper.
Group:Seismological Laboratory
Funding AgencyGrant Number
Academy of Finland128189
Academy of Finland131350
Subject Keywords:climate change; correlation; geomagnetism; hypothesis testing; magnetic storms; sunspots
Issue or Number:21
Record Number:CaltechAUTHORS:20111213-144757573
Persistent URL:
Official Citation:Love, J. J., K. Mursula, V. C. Tsai, and D. M. Perkins (2011), Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?, Geophys. Res. Lett., 38, L21703, doi:10.1029/2011GL049380.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:28458
Deposited By: Ruth Sustaita
Deposited On:14 Dec 2011 15:41
Last Modified:09 Nov 2021 16:57

Repository Staff Only: item control page