Potential analysis reveals changing number of climate states during the last 60 kyr 1School of Environmental Sciences, University of East Anglia, Norwich, UK
2College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
Received: 28 August 2009 – Published in Clim. Past Discuss.: 30 September 2009 Abstract. 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.
Revised: 06 January 2010 – Accepted: 10 February 2010 – Published: 17 February 2010
Citation: Livina, V. N., Kwasniok, F., and Lenton, T. M.: Potential analysis reveals changing number of climate states during the last 60 kyr, Clim. Past, 6, 77-82, doi:10.5194/cp-6-77-2010, 2010.