The longterm evolution of the Sun's activity is of crucial interest, when trying to understand both recent and historical climatic changes. On timescales beyond the direct observation through sunspots, one has to rely on records of cosmogenic radionuclides, such as 14C and 10Be. These radionuclides can be found, for example, in tree rings and ice cores. Their production rates are modulated by solar activity, but also by the Earth's magnetic field, and thus contain an entangled signal of their evolution.
We constructed a joint statistical model of solar activity and the global geomagnetic field, accounting for a possible bi-modality in solar modulation, due to the occurrence of grand solar minima. Inversion of 10Be data from Greenland (GRIP) and Antarctica (EDML), 14C data from IntCal20 and global thermoremanent magnetic data from GEOMAGIA provides no convincing evidence for longterm solar variability over the Holocene, apart from possible clustering of grand solar minima. Additionally, the radionuclide records do not provide strong constraints on the time-averaged symmetry of the global geomagnetic field, due to a lack of calibration and lack of magnetic data from the southern hemisphere.
How to cite:
Schanner, M. A., Nilsson, A., and Muscheler, R.: Thermoremanent magnetic, 10Be and 14C data provide no convincing evidence for longterm solar variability in the Holocene, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10115, https://doi.org/10.5194/egusphere-egu25-10115, 2025.
Share
Please decide on your access
Please use the buttons below to download the supplementary material or to visit the external website where the presentation is linked. Regarding the external link, please note that Copernicus Meetings cannot accept any liability for the content and the website you will visit.
You are going to open an external link to the presentation as indicated by the authors. Copernicus Meetings cannot accept any liability for the content and the website you will visit.