The Paleochrono-1.1 probabilistic model to derive a common age model for several paleoclimatic sites using absolute and relative dating constraints
Year: 2024
Type: article
Abstract: . Past climate and environmental changes can be reconstructed using paleoclimate archives such as ice cores, lake and marine sediment cores, speleothems, tree rings and corals. The dating of these natural archives is crucial for deciphering the temporal sequence of events and rates of change during past climate changes. It is also essential to provide quantified estimates of the absolute and relative errors associated with the inferred chronologies. However, this task is complex since it involves combining different dating approaches at different paleoclimatic sites and often on different types of archives. Here we present Paleochrono-1.1, a new probabilistic model to derive a common and optimised chronology for several paleoclimatic sites with potentially different types of archives. Paleochrono-1.1 is based on the inversion of an archiving model: a varying deposition rate (also named growth rate, sedimentation rate or accumulation rate) and also, for ice cores, a lock-in-depth of air (since, in the absence of significant surface melt, the air is trapped in the ice at about 50–120 m below the surface) and a thinning function (since glacier ice undergoes flow). Paleochrono-1.1 integrates several types of chronological information: prior knowledge of the archiving process, independently dated horizons, depth intervals of known duration, undated stratigraphic links between records, and, for ice cores, Δdepth observations (depth differences between events recorded synchronously in the gas and solid phases of a certain core). The optimization is formulated as a least-squares problem, assuming that all probability densities are near-Gaussian and that the model is nearly linear in the vicinity of the best solution. Paleochrono-1.1 is the successor of IceChrono, which produces common and optimized chronologies for ice-cores. Paleochrono1.1 outperforms IceChrono in terms of computational efficiency, ease of use, and accuracy. We demonstrate the ability of Paleochrono-1.1 in a new ice-core–speleothem dating experiment, which combines the Antarctic Ice Core Chronology 2023 dating experiment, based on records from five polar ice cores, with data from two speleothems dated using uranium/thorium radiometric techniques from Hulu Cave (China). We analyse the performance of Paleochrono-1.1 in terms of computing time and memory usage in various dating experiments. Paleochrono-1.1 is freely available under the MIT open-source license.
Source: Geoscientific model development
Institutions: Institut polytechnique de Grenoble, Centre National de la Recherche Scientifique, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Institut des Géosciences de l'Environnement, Institut de Recherche pour le Développement, Université Grenoble Alpes, Université de Versailles Saint-Quentin-en-Yvelines, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Laboratoire des Sciences du Climat et de l'Environnement, Oregon State University, Monash University, The University of Melbourne, National Institute of Polar Research, Research Organization of Information and Systems, British Antarctic Survey, University of Copenhagen
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $1,725
Awards: Collaborative Research: The Timing and Spatial Expression of the Bipolar Seesaw in Antarctica from Synchronized Ice Cores, G159773988, G1690891631, Beyond EPICA - Oldest Ice, G2392386789, Beyond EPICA Oldest Ice Core: 1,5 Myr of greenhouse gas – climate feedbacks, G3010527862, 南極ドームふじ氷床コアの精密年代決定で解く氷期サイクルの根本要因, G4098071017, G434337789, G5078105200, G5447028118, G5528339242, マルチスケール宇宙線生成核種分析より紐解く地質時代の宇宙・地球現象と環境変動, Towards Beyond EPICA, Characterisation & Dynamics of Past Warm Climates, Inter-Hemispheric Climate Teleconnections in response to Massive Iceberg Discharge in the North Atlantic, 最終間氷期の南極は本当に現在より6度も暖かったのか？氷床コアデータの逆解析で解く
OpenAlex ID: W4405208094