Characterisation of Dansgaard-Oeschger events in palaeoclimate time series using the Matrix Profile

• Main Authors: Barbosa, Susana, Silva, Maria, Eduarda, Rousseau, Denis-Didier
• Other Authors: Institute for Systems and Computer Engineering, Technology and Science Porto (INESC TEC), Lamont-Doherty Earth Observatory (LDEO), Columbia University New York, Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Université de Montpellier (UM), European Commission, Horizon 2020 Framework Programme, European Project: grant no. 820970,TiPES
• Format: Report
• Language: English
• Published: HAL CCSD 2024
• Subjects: Abrupt transitions; Millennial climate variability; matrix profile approach; Dansgaard-Oeschger events; Greenland ice core; delta18O and Ca2+ time series; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Greenland; ice core
• Online Access: https://hal.science/hal-04587624; https://hal.science/hal-04587624/document; https://hal.science/hal-04587624/file/npg-2024-13.pdf; https://doi.org/10.5194/npg-2024-13

Palaeoclimate time series, reflecting the state of Earth’s climate in the distant past, display occasionally very large and rapid shifts, evidencing abrupt climate variability. The identification and characterisation of these abrupt transitions in palaeoclimate records is of particular interest as it allows the understanding of millennial climate variability and the identification of potential tipping points in the context 5 of current climate change. Methods that are able to characterise these events in an objective and automatic way, in a single time series or across two proxy records, are therefore of particular interest. In our study the matrix profile approach is used to describe Dansgaard-Oeschger (DO) events, abrupt warmings detected in Greenland ice core, and Northern Hemisphere marine and continental records. The results indicate that canonical events DO-19 and DO-20, occurring at around 72 and 76 ka, are the most similar events over the past 110,000 years. These transitions are characterised by matching 10 transitions corresponding to events DO-1, DO-8 and DO-12. These transitions are abrupt, resulting in a rapid shift to warmer conditions, followed by a gradual return to cold conditions. The joint analysis of the _18 O and Ca2+ time series indicates that the transition corresponding to the DO-19 event is the most similar event across the two time series.