Modelling cosmic radiation events in the tree-ring radiocarbon record

Abstract

Annually resolved measurements of the radiocarbon content in tree-rings have revealed rare sharp rises in carbon-14 production. These ‘Miyake events’ are likely produced by rare increases in cosmic radiation from the Sun or other energetic astrophysical sources. The radiocarbon produced is not only circulated through the Earth’s atmosphere and oceans, but also absorbed by the biosphere and locked in the annual growth rings of trees. To interpret high-resolution tree-ring radiocarbon measurements therefore necessitates modelling the entire global carbon cycle. Here, we introduce ‘ ticktack ’ ( https://github.com/SharmaLlama/ticktack/ ), the first open-source Python package that connects box models of the carbon cycle with modern Bayesian inference tools. We use this to analyse all public annual 14 C tree data, and infer posterior parameters for all six known Miyake events. They do not show a consistent relationship to the solar cycle, and several display extended durations that challenge either astrophysical or geophysical models.

Absolute dating of the European Neolithic using the 5259 BC rapid 14C excursion

“…The year-to-year increase in Δ 14 C presented in the Results section was calculated as a difference between the values in 5260 BC and 5259 BC (sensu Miyake et al 19 ). For a detailed discussion on the magnitude and 14 C production during the 5259 BC Miyake event see 22 and 109 .…”

ticktack: A Python package for carbon box modelling

“…We employ an object-oriented framework, with classes for • Box and Flow, a lightweight interface for specifying reservoirs and the flows between them, which can be compiled to a • CarbonBoxModel, which stores these metadata and whose main method run solves the CBM ODE for an arbitrary production function and time steps using diffrax; • SingleFitter, which stores a single tree's ΔC 14 data and a CarbonBoxModel as attributes, and can sample their log-likelihood using emcee; • MultiFitter, which takes a list of SingleFitter objects and provides a similar interface to their joint log-likelihood. We have applied this in our team's accompanying science paper (Zhang et al, 2022) to systematically analyse all extant public data on the six known Miyake events, finding no relationship to the solar cycle, and hints of a nonzero duration in several of the events. Moreover we hope that our toolkit will be adopted more widely in the radiocarbon community, and encourage other developers to contribute to the ongoing development of this open-source code base.…”

Jeomanyetik Firtinalar, Gözlemevleri Ve Ülkemizde Jeomanyetik Kp İndisinin Hesaplanmasi

“…Bu fırtınalardan kaynaklanan taçküre kütle atımları enerjisi yüksek parçacıkları ivmelendirebilir ve bu parçacıklar da Dünya'nın atmosferinde radyokarbon oluşumuna neden olur. Güneş fırtınaları radyokarbon etkisinden başlayarak pek çok farklı alanda etkilere sahiptir (Zhang, 2022). Güneş aktivitesinin maksimum olduğu dönemde Güneş fırtınaları ve taçküre kütle atımlarının da yoğunluğu artar.…”