American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 221791 bytes)    Cited by

GEOPHYSICAL RESEARCH LETTERS, VOL. 29, NO. 23, 2107, doi:10.1029/2002GL015646, 2002

A new look at possible connections between solar activity, clouds and climate

J. E. Kristjánsson

Department of Geophysics, University of Oslo, Oslo, Norway


A. Staple

Department of Geophysics, University of Oslo, Oslo, Norway


J. Kristiansen

Department of Geophysics, University of Oslo, Oslo, Norway


E. Kaas

Danish Meteorological Institute, Copenhagen, Denmark


Abstract

We present a re-evaluation of the hypothesis of a coupling between galactic cosmic rays, clouds and climate. We have used two independent estimates of low cloud cover from the International Satellite Cloud Climatology Project, covering 16.5 years of data. The cloud cover data are used in conjunction with estimates of galactic cosmic ray flux and measurements of solar irradiance. It is found that solar irradiance correlates better and more consistently with low cloud cover than cosmic ray flux does. The correlations are considerably lower when multichannel retrievals during daytime are used than retrievals using IR-channels only. Due to large autocorrelations, the statistical significance of the results is marginal. A mechanism is suggested whereby solar irradiance variations are amplified by interacting with sea surface temperature (SST), and subsequently low cloud cover. The feasibility of such a mechanism is supported by negative correlations between SSTs and low cloud cover in subtropical regions.

Published 7 December 2002.

Index Terms: 1650 Global Change: Solar variability; 7536 Solar Physics, Astrophysics, and Astronomy: Solar activity cycle (2162); 3360 Meteorology and Atmospheric Dynamics: Remote sensing; 2104 Interplanetary Physics: Cosmic rays.

Read Full Article (file size: 221791 bytes)    Cited by

Citation: Kristjánsson, J. E., A. Staple, J. Kristiansen, and E. Kaas (2002), A new look at possible connections between solar activity, clouds and climate, Geophys. Res. Lett., 29(23), 2107, doi:10.1029/2002GL015646.