Saturday, January 19th 2013, 11:53 AM EST
Fig. 2. Variations of external factors: (top panel) solar activity (SSN) and the C9-index of geomagnetic activity (dimensionless index); (bottom panel) variations of DVIGlobal (dimensionless index) and the aerosol backscattering coefficients () at wavelength 694.3 nm. The solid vertical lines indicate the dates of intensive volcanic eruptions (Volcanic Explosive Index (VEI) ≥ 5.0) for 1880–1991.
A paper published today in the Journal of Atmospheric and Solar-Terrestrial Physics finds a significant influence of solar activity upon Earth temperature during the second half of the 20th century.
The authors find surface temperature linked to the 11-year solar cycle, and also influenced by the timing of volcanic eruptions. Once again, the claim by climate alarmists that small variations in solar activity cannot control temperature or climate has been debunked by observations.
Abstract
In this paper we analyze the geographical distribution of the climate response to external forcing (solar, volcanic and geomagnetic) on the periods of 11 and 22 years. As a climate characteristic we use the data of the air-surface temperature (regional data sets).
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The analysis is performed by the wavelet phase/coherence technique which is applied to the solar (sunspot numbers), volcanic (Dust Veil Index), geomagnetic (C9-index) activities and the temperature data on interannual timescales for the common time interval covering most of the 20th century. Besides, we analyze the statistics of the temperature response to the solar and geomagnetic factors on the periods of 11 and 22 years for different geographical sectors.
In particular, we find the existence of a combined forcing of solar and volcanic activity on the Earth temperature on the 11-year period in the second half of the 20th century over the globe, whereas a set of stations (mostly in North Atlantic) shows a coherence between solar activity and the Earth temperature on the 11-year periodicity even in absence of the combined effect; it was found that the maximal number of stations demonstrating statistically significant amplitudes of wavelet spectra corresponds to the wavelet cross coherence between geomagnetic activity and the Earth air-surface temperature on the periods about 22 years during the time interval without intensive volcanic eruptions capable to change significantly the level of DVIGlobal.
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