A SIMPLE CONCEPTUAL MODEL TO INTERPRET THE 100,000 YEARS DYNAMICS OF PALEO-CLIMATE RECORDS

BALENZUELA, PABLO; QUIROGA-LOMBARD, CLAUDIO SEBASTIÁN; BRAUN HOLGER; CHIALVO, DANTE R

San Pablo, Brasil

Conferencia; Dynamics Days South America 2010; 2010

INPE – National Institute for Space Research

A global perspective of the climate records from the North Atlantic region for the last ice age suggests that tem- perature variations are the result of the switching between two stable states (a warm and a cold one) with different dy- namical regimes, being the quasi-periodicity of about 1470 years during the interval 12 − 50 kyr BP one of those dynam- ical regimes. The hypothesis underlying the present work is that the existence of a driving force composed by the near De Vries/Suess and Gleissberg cycles (with phases and rel- ative amplitudes obtained from a 14C spectral analysis) plus a Gaussian noise (representing the multiples degrees of free- dom that we do not take explicitly account for) control the transitions between both states. If so, this simple scheme should explain the main features of temperature variations for the whole ice age and the effects of the solar forcing should be noticeable also during the Holocene when DO events were absent. To test this hypothesis we propose a new conceptual model based on the key assumptions of the CLIMBER-2 and the information obtained after having analyzed two climate records, the GISP2 δ18O and 14C measurements from tree rings. These records are commonly used as proxies for tem- perature and solar activity, despite the fact that it is known that 14C can be affected by a number of processes, including exchange between the atmosphere and the ocean, variations in geomagnetic fields, and changes in vegetation, among oth- ers.