Solar-type periodicities in the climate variability of Northern Fennoscandia during the last three centuries: Real influence of solar activity or natural instability in the climate system

Abstract

Fifteen proxy records of summer temperature in Fennoscandia, Northern Europe and in Yamal and Taymir Peninsulas (Western Siberia) were analyzed for the AD 1700–2000 period. Century-long (70–100 year) and quasi bi-decadal periodicities were found from proxy records representing different parts of Fennoscandia. Decadal variation was revealed in a smaller number of records. Statistically significant correlations were revealed between the timescale-dependent components of temperature variability and solar cycles of Schwabe (~11 year), Hale (~22 year), and Gleissberg (сentury-long) as recorded in solar activity data. Combining the results from our correlation analysis with the evidence of solar-climatic linkages over the Northern Fennoscandia obtained over the past 20 years suggest that there are two possible explanations for the obtained solar-proxy relations: (a) the Sun’s activity actually influences the climate variability in Northern Fennoscandia and in some regions of the Northern Hemisphere albeit the mechanism of such solar-climatic linkages are yet to be detailed; (b) the revealed solar-type periodicities result from natural instability of climate system and, in such a case, the correlations may appear purely by chance. Multiple lines of evidence support the first assumption but we note that the second one cannot be yet rejected. Guidelines for further research to elucidate this question are proposed including the Fisher’s combined probability test in the presence of solar signal in multiple proxy records.

Challenges in the Detection and Attribution of Northern Hemisphere Surface Temperature Trends Since 1850

“…Moreover, our analysis also explicitly assumes that there is a direct linear relationship between ST and each of the forcings. However, many studies have suggested that the relationship between solar activity and ST is subtler and more complex than a simple linear relationship to TSI (Roy 2014;Kilifarska 2015;Sfică et al 2018;Svensmark et al 2021;Stefani 2021;Ogurtsov et al 2022;Scafetta 2023;Kumar et al 2023). Similarly, concerns have been raised over the modeled climate response to volcanic forcings, e.g., Lindzen & Giannitsis (1998), Chylek et al (2020), Khaykin et al (2022).…”

Revealing Coupled Periodicities in Sunspot Time Series Using Bispectrum—An Inverse Problem

“…The studies by Vinay Kumar et al [16] as well as by Maxim Ogurtsov et al [17] and Potrzeba-Macrina and Zurbenko [18] highlight the future challenges and research directions, emphasizing how regional-scale atmospheric circulation can aid in understanding solarinduced climate variability. Furthermore, Wei Lu et al [19] conducted a study to explore the potential connection between the summer temperature distribution over Eurasian land and solar activity, while Thomas and Abraham [20] focused on investigating the periodicities of rainfall over Kerala, India, and sunspot numbers, and explored the possible associations between these factors.…”

“…(b). Since (1,1) is the position of dc, the coupling edge is present at coordinates(5,17), i.e., for coupled frequencies 4 and 16. The created 20th harmonic does not present any footprint in the region of the bispectrum, which is enclosed in the red line.…”