Potential analysis reveals changing number of climate states during the last 60 kyr

• Published in: Climate of the Past
• Main Authors: Livina, VN, Kwasniok, F, Lenton, TM
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2010
• Subjects: Greenland; ice core
• Online Access: https://ueaeprints.uea.ac.uk/id/eprint/20357/; https://doi.org/10.5194/cp-6-77-2010

We develop and apply a new statistical method of potential analysis for detecting the number of states of a geophysical system, from its recorded time series. Estimation of the degree of a polynomial potential allows us to derive the number of potential wells in a system. The method correctly detects changes in the number of wells in artificial data. In ice-core proxy records of Greenland paleotemperature, a reduction in the number of climate states from two to one is detected sometime prior to the last glacial maximum (LGM), 23-19 kyr BP. This result is also found in analysis of Greenland Ca data. The bifurcation can be interpreted as loss of stability of the warm interstadial state of the Dansgaard-Oeschger (DO) events. The proposed method can be applied to a wide range of geophysical time series exhibiting bifurcations.