ROLE OF THE RADIATION
FACTOR IN GLOBAL CLIMATIC EVENTS
OF THE LATE HOLOCENE
© 2021 V.M. Fedorov1*, D.M. Frolov1, V.M.N. Velasco Herrera2, W.W.-H. Soon3, 4, R.G. Cionco5
1 Lomonosov Moscow State University, Geographical Faculty, Moscow, Russia
2 Instituto de Geofisica, Universidad Nacional Autónoma de México, Mexico, México
3.Harvard & Smithsonian Center for Astrophysics, Division of Solar, Stellar, and Planetary Sciences, Cambridge, USA
4 Institute of Earth Physics and Space Science, Sopron, Hungary
5 Universidad Tecnológica Nacional, Grupo de Estudios Ambientales, Buenos Aires, Argentina
*e-mail: fedorov.msu@mail.ru
Abstract. On the basis of the performed calculations of insolation and insolation characteristics, taking into account changes in solar activity, the causes of global climatic events in the late Holocene were determined. The main reasons for the Little Ice Age are the long and deep minimum of summer insolation and insolation seasonality in the northern hemisphere. The values of the minimums are fixed in the range of approximately 1400–1750. The depth of the minimum over the past 5000 years, taking into account the change in solar activity, is about 8.0 W/m2 for summer insolation and about 13.3 W / m2 for insolation seasonality in the northern hemisphere. The medieval climatic optimum is associated with the winter maximum of insolation contrast in the northern hemisphere, reflecting an increase in the meridional heat transfer in the winter half of the year from the equatorial region to the polar regions, as well as with a maximum of interhemispheric heat transfer. Increase in winter insolation contrast at maximum (1118) relative to 3000 BC is 28.4 W/m2. The difference between the hemispheric radiative heat transfer at the maximums (881, 940, and 976) increases by 5.0 W/m2, relative to 3000 BC.
A synchronicity was found between the extreme values of insolation characteristics (taking into account the change in solar activity) and global climatic events of the late Holocene. The role of the radiation factor in changes in the global climate in the sub-Holocene history of the Earth has been determined. The ratios of solar radiation variations of different physical nature in the total solar radiation flux and its characteristics (incoming radiation, insolation contrast, insolation seasonality of the Earth and hemispheres) have been determined.
On a millennial scale, variations associated with the activity of the Sun are weakly expressed against the background of more prolonged variations determined by the Earth’s orbital motion and the tilt of the axis of its rotation. However, on the scale of centuries, variations determined by solar activity become significant and make it possible to detail the extremes of insolation characteristics determined by changes in the parameters of the Earth’s orbital motion and the inclination of the axis of its rotation. That is, global events of the Late Holocene are associated with extremes of insolation characteristics, but the temporal structure of insolation extremes is determined by variations in solar activity. Variations associated with solar activity are not manifested in interhemispheric heat transfer. This is due to the fact that within half a year the variations associated with the activity of the Sun in the hemispheres are the same.
Thus, when reconstructing and predicting global climatic events, it is important to take into account not only variations in the incoming radiation, but also related changes in insolation characteristics (insolation contrast and insolation seasonality of the Earth and hemispheres), reflecting the mechanisms of heat transfer. IR reflects meridional heat transfer and is associated with a change in axis tilt and precession. Insolation seasonality of the Earth – reflects the intensity of interhemispheric heat transfer. The insolation seasonality of the hemisphere is an indicator of the intensity of heat transfer in the ocean-mainland system. The noted characteristics of insolation, reflecting the mechanisms of heat transfer, are not taken into account in the astronomical theory of climate. Taking into account insolation characteristics, reflecting not only variations in the arrival of solar radiation, but also variations in the mechanisms of heat transfer, can contribute to the further development of the astronomical theory of climate.
Keywords: insolation, insolation characteristics, heat exchange, solar activity, late Holocene, Little Ice Age, medieval climatic optimum.
About the authors
FEDOROV Valery Mikhaylovich – Lomonosov Moscow State University, Geographical Faculty. Russia, 119991, Moscow, Leninskie Gory, 1. E-mail: fedorov.msu@mail.ru
FROLOV Denis Maksimovich – Lomonosov Moscow State University, Geographical Faculty. Russia, 119991, Moscow, Leninskie Gory, 1. E-mail: denisfrolovm@mail.ru
VELASCO HERRERA Victor Manuel Naumovich – Instituto de Geofisica, Universidad Nacional Autonoma de México. Cludad Universitaria, Mexico, 04510, México. E-mail: vmv@igeofisica.unam.mx
SOON Willy W.-H. – Harvard & Smithsonian Center for Astrophysics, Division of Solar, Stellar, and Planetary Sciences. Cambridge, Garden street, 60, 02138, Massachusetts, USA; Institute of Earth Physics and Space Science. Sopron, 9400, Hungary. E-mail: wsoon@cfa.harvard.edu
CIONCO Rodolfo Gustavo – Universidad Tecnológica Nacional, Grupo de Estudios Ambientales. Colón 332, Barrio de San Nicolás, Buenos Aires, 2900, Argentina. E-mail: gcionco@frsn.utn.edu.ar
Cite this article as: Fedorov V.M., Frolov D.M., Velasco Herrera V.M.N., Soon W.W.-H., Cionco R.G. Role of the radiation factor in global climatic events of the Late Holocene, Geofizicheskie Protsessy i Biosfera (Geophysical Processes and Biosphere), 2021, vol. 20, no. 3, pp. 5–19 (in Russian). https://doi.org/10.21455/gpb2021.3-1
English version: Izvestiya, Atmospheric and Oceanic Physics, 2021, vol. 57, iss. 10. ISSN: 0001-4338 (Print), 1555-628X (Online). https://link.springer.com/journal/volumesAndIssues/11485