| The statistical relationship between the smoothed curve for solar cycle
length and northern hemisphere land mean temperature has been a source of
investigation in the question of whether and how much the Sun influences
climate variations. The relationship was widely discussed following the
1991 paper by Friis-Christensen and Lassen and was updated in 2000 by
Thejll and Lassen. Data for one more solar cycle has now accumulated, and
the relationship is again reviewed and discussed. We derive and show
the updated SCL and mean temperature curves. The relationship between the
two is analysed using standard statistical methods. Additional climate
forcing factors are introduced to improve the fit. Changes in the
historical part of the mean temperature curve has occurred which modifies
the previously seen relationship, and this is discussed. |