Logo PIK

Potsdam Institute for Climate Impact Research (PIK) – Group Development of advanced time series analysis techniques

The Potsdam Institute is a non-university research institute primarily concerned with questions about the causes and effects of climate change and with developing policy options to mitigate climate risks. It was founded in 1992 and is a member of the Leibniz Association.

The group “Development of advanced time series analysis techniques ↗” of the department “Complex Systems ↗” is involved in the research at Bleßberg Cave. Here, together with the partners, the age models for the stalagmites are calculated and complex statistical evaluations of the palaeoclimate data are carried out.

Contact

Dr. Norbert Marwan ↗

Web site

https://www.pik-potsdam.de/ ↗

Publications

Marwan, Norbert; Kraemer, Kai Hauke; Wiesner, Karolin; Breitenbach, Sebastian F. M.; Leonhardt, Jens

Recurrence based entropies Presentation

07.05.2019, (Fourth International Conference on Recent Advances in Nonlinear Mechanics, Łódz (Poland)).

Abstract | BibTeX

Marwan, Norbert; Kraemer, Kai Hauke; Wiesner, Karolin; Breitenbach, Sebastian F. M.; Leonhardt, Jens

Recurrence based entropies Inproceedings

Geophysical Research Abstracts, pp. EGU2019-2817, 2019.

Abstract | Links | BibTeX

Breitenbach, Sebastian F. M.; Plessen, Birgit; Waltgenbach, Sarah; Tjallingii, Rik; Leonhardt, Jens; Jochum, Klaus-Peter; Meyer, Hanno; Goswami, Bedartha; Marwan, Norbert; Scholz, Denis

Holocene interaction of maritime and continental climate in Central Europe: New speleothem evidence from Central Germany Journal Article

Global and Planetary Change, 176 , pp. 144–161, 2019.

Abstract | Links | BibTeX

Breitenbach, Sebastian F. M.; Plessen, Birgit; Waltgenbach, Sarah; Tjallingii, Rik; Leonhardt, Jens; Jochum, Klaus-Peter; Meyer, Hanno; Marwan, Norbert; Scholz, Denis

Tracing past shifts of the boundary between maritime and continental climate over Central Europe Inproceedings

Geophysical Research Abstracts, pp. EGU2018-9046, 2018.

Abstract | Links | BibTeX

Breitenbach, Sebastian F. M.; Plessen, Birgit; Wenz, Sarah; Leonhardt, Jens; Tjallingii, Rik; Scholz, Denis; Jochum, Klaus-Peter; Marwan, Norbert

A multi-proxy reconstruction of Holocene climate change from Blessberg Cave, Germany Inproceedings

Geophysical Research Abstracts, pp. EGU2016-14213, 2016.

Abstract | Links | BibTeX

Marwan, Norbert; Breitenbach, Sebastian F. M.; Plessen, Birgit; Scholz, Denis; Leonhardt, Jens

Recurrence properties as signatures for abrupt climate change Inproceedings

Geophysical Research Abstracts, pp. EGU2014-8893, 2014.

Abstract | Links | BibTeX

Novel methods for studying palaeoclimate dynamics

Marwan, Norbert; Kraemer, Kai Hauke; Wiesner, Karolin; Breitenbach, Sebastian F. M.; Leonhardt, Jens

Recurrence based entropies Presentation

07.05.2019, (Fourth International Conference on Recent Advances in Nonlinear Mechanics, Łódz (Poland)).

Abstract | BibTeX

Marwan, Norbert; Kraemer, Kai Hauke; Wiesner, Karolin; Breitenbach, Sebastian F. M.; Leonhardt, Jens

Recurrence based entropies Inproceedings

Geophysical Research Abstracts, pp. EGU2019-2817, 2019.

Abstract | Links | BibTeX

At PIK, among other things, new methods are being developed that, on the one hand, can be used to investigate new aspects in palaeoclimate data, but on the other hand can also cope with the difficulties usually associated with palaeoclimate analyses – such as gaps in data series, uncertainties in the dating, or irregularities in the data sampling. Although this is basic research, it is also immediately applied to interesting questions.

In this example, a method was developed to determine the regularity of certain recurring pattern in the data. The technical terms here are “recurrence” and “entropy” (a measure of disorder). Methods that look for recurring patterns are used in various disciplines, not only in the geosciences, but also in medicine, mechanical engineering, finance, and so on. Besides finding abrupt changes, they are also used for comparing different data sets or for classification (e.g. for machine learning).

The newly developed method was applied to the carbon isotopeIsotop Chemische Elemente können aus verschieden aufgebauten Atomen gebildet sein. Die Anzahl Protonen im Atomkern ist zwar dabei gleich, aber die Anzahl der Neutronen kann variieren. Man spricht dann von Isotopen, deren Massen kleine, aber messbare Unterschiede aufweisen. Der Atomkern des Sauerstoffs besteht z. B. aus 8 Protonen und in der Regel aus 8 Neutronen. Es gibt aber auch Sauerstoff, dessen Kerne aus 8 Protonen und 9 oder 10 Neutronen bestehen (neben selteneren, instabilen Sauerstoffisotopen). Um das zu kennzeichnen, gibt man zusätzlich zum chemischen Symbol noch die Massenzahl (Summe aus Protonen und Neutronen) an, also 16O, 17O oder 18O. Die unterschiedlichen Isotope verhalten sich zwar chemisch identisch, physikalisch aber - aufgrund ihres unterschiedlichen Gewichtes - leicht unterschiedlich. Damit stellen sie äusserst wertvolle Marker dar, die uns wichtige Hinweise zur Änderung des Klimas, der Umgebungsvegetation, Bodenaktivität und vielem mehr geben. data from BB-1 and BB-3 (for this purpose, the data from both stalagmites were combined into one long data series using a special procedure). Interestingly, there are regular differences during the influence of the maritime climate (Atlantic influence) and during the influence of the continental climate. During the Atlantic influence, the climate seems to have changed more regularly than during the dominant continental climate (this may be related to the regular change of cold events in the North Atlantic, so-called “Bond events”, or to the North Atlantic Oscillation). This could be used to extend our knowledge about the migration of the climate zone boundary, as known for the last 4,000 years (see Climate Zone Shift in central Europe), further into the past. Whenever the new measure indicates that there were more regular climate dynamics, the climate zone boundary was further east of the Bleßberg Cave.

Abrupt Climate Change

Marwan, Norbert; Breitenbach, Sebastian F. M.; Plessen, Birgit; Scholz, Denis; Leonhardt, Jens

Recurrence properties as signatures for abrupt climate change Inproceedings

Geophysical Research Abstracts, pp. EGU2014-8893, 2014.

Abstract | Links | BibTeX

Among other things, new methods are being developed at PIK that, on the one hand, investigate new aspects in palaeoclimate data, but also cope with the difficulties usually associated with palaeoclimate analyses – such as gaps in the data, age uncertainties, or irregularities in the data sampling. While this is basic research, it is also immediately applied to interesting research questions.

One focus is the development and application of methods that specifically investigate recurring patterns. These methods are very successful for finding abrupt changes, but also for comparing different data sets, e.g., to detect mutual influences.

In one of our first analyses of the three stalagmites BB-1 to BB-3, we had looked at the oxygen isotopes of BB-1 with recurrence based methods. Thereby we had explicitly considered dating uncertainties. Due to the dating uncertainties there are small shifts of the time series along the x-axis. Therefore, within the uncertainties, different realizations of the course of the measured oxygen isotopes are possible.

Sauerstoffisotope von BB-1
Oxygen isotopes of BB-1. Due to the dating uncertainties, there are several possibilities when changes in this climate archive happened. The stalagmite grew from about 6,000 years ago to about 400 years ago.

The recurrence patterns are examined with a special analysis tool, the so-called “recurrence plot”. This can be used to plot times when similar states have occurred. The patterns seen in such a recurrence plot have a deeper meaning and can be further analyzed and quantified to find changes in the dynamics of the underlying process.

Recurrence plot der Sauerstoffisotope von BB-1
Recurrence plot of one realization of the measured oxygen isotopes in BB-1.

The numerical analysis of recurrence plots yields various results that shed light on different aspects of climate dynamics. Two such results are briefly presented here: on the one hand, the complexity of climate variability (“transitivityTransitivity Ein Maß aus der Netzwerktheorie, welches quantifiziert, wie stark sich Zustände zu kleinen Gruppen zusammenfinden.”) and, on the other hand, how well such a climate signal would be predictable (“determinismDeterminism Ein Maß aus der Wiederkehr-Analyse, welches beschreibt, wie gut sich die Veränderung eines Systems vorhersagen läßt.”). Both results show a general tendency towards greater complexity and lower predictability for younger ages. However, they also show short-lived increases to better predictability for certain time points, namely about 4,200, 2,800, and 1,400 years ago. It was precisely at these times that short-lived and rapid glaciations occurred in the North Atlantic, the so-called “Bond events.” Moreover, there are variations in the complexity of the climate signal (“transitivity”), but these variations are within the range of uncertainty (confidence interval), so we cannot really interpret them.

Recurrence quantification der Sauerstoffisotope von BB-1
Quantitative analysis of recurrence patterns in oxygen isotopeIsotop Chemische Elemente können aus verschieden aufgebauten Atomen gebildet sein. Die Anzahl Protonen im Atomkern ist zwar dabei gleich, aber die Anzahl der Neutronen kann variieren. Man spricht dann von Isotopen, deren Massen kleine, aber messbare Unterschiede aufweisen. Der Atomkern des Sauerstoffs besteht z. B. aus 8 Protonen und in der Regel aus 8 Neutronen. Es gibt aber auch Sauerstoff, dessen Kerne aus 8 Protonen und 9 oder 10 Neutronen bestehen (neben selteneren, instabilen Sauerstoffisotopen). Um das zu kennzeichnen, gibt man zusätzlich zum chemischen Symbol noch die Massenzahl (Summe aus Protonen und Neutronen) an, also 16O, 17O oder 18O. Die unterschiedlichen Isotope verhalten sich zwar chemisch identisch, physikalisch aber - aufgrund ihres unterschiedlichen Gewichtes - leicht unterschiedlich. Damit stellen sie äusserst wertvolle Marker dar, die uns wichtige Hinweise zur Änderung des Klimas, der Umgebungsvegetation, Bodenaktivität und vielem mehr geben. measurements of BB-1.