Chapter 2
GLOBAL ATMOSPHERIC EVOLUTION
Impact of Anthropogenic Activities
MODELING PALEOCLIMATIC CHANGES USING A
FEEDBACK ENERGETIC SYSTEM. PREDICTION OF
MEAN ICE GLOBAL VARIATIONS.
Paul ALLE
C.R.P.G - C.N.R.S, 15 rue Notre Dame des Pauvres, BP 20, 54501
Vandoeuvre-les-Nancy Cedex, France.
ABSTRACT
It has been noted that several distinct ice ages existed during the past million
years. Among other things, the marine sediment 8 18 0 record, interpreted as the
variation through time of the ice mass, indirectly confirms the Milankovitch
hypothesis that orbital variation governs climatic changes, and leads to a great
number of sophisticated models. A simplified feedback model for the global
variations in time of ice volume, mean surface temperature and atmospheric
carbon dioxide concentration is constructed. The transfer function of the system
came from our differential equation system solved by using Laplace and Ztransform techniques. The system must conserve energy, the input being the
incident solar energy and the output the energy radiated by the earth. The
atmosphere and surface of the earth are assumed to be a fast responding climatic
system, while the ocean and ice shell have a slower response. The difference in the
time constants of the main reservoirs explains the phase shift between the input
and the output of the system and its transient behaviour. As a hypothesis the
glaciers have a non linear response. This simplified approach makes possible
C. Bardinet et al. (eds.), Geosciences and Water Resources: Environmental Data Modeling
© Springer-Verlag Berlin Heidelberg 1997
GLOBAL ATMOSPHERIC EVOLUTION
Impact of Anthropogenic Activities
MODELING PALEOCLIMATIC CHANGES USING A
FEEDBACK ENERGETIC SYSTEM. PREDICTION OF
MEAN ICE GLOBAL VARIATIONS.
Paul ALLE
C.R.P.G - C.N.R.S, 15 rue Notre Dame des Pauvres, BP 20, 54501
Vandoeuvre-les-Nancy Cedex, France.
ABSTRACT
It has been noted that several distinct ice ages existed during the past million
years. Among other things, the marine sediment 8 18 0 record, interpreted as the
variation through time of the ice mass, indirectly confirms the Milankovitch
hypothesis that orbital variation governs climatic changes, and leads to a great
number of sophisticated models. A simplified feedback model for the global
variations in time of ice volume, mean surface temperature and atmospheric
carbon dioxide concentration is constructed. The transfer function of the system
came from our differential equation system solved by using Laplace and Ztransform techniques. The system must conserve energy, the input being the
incident solar energy and the output the energy radiated by the earth. The
atmosphere and surface of the earth are assumed to be a fast responding climatic
system, while the ocean and ice shell have a slower response. The difference in the
time constants of the main reservoirs explains the phase shift between the input
and the output of the system and its transient behaviour. As a hypothesis the
glaciers have a non linear response. This simplified approach makes possible
C. Bardinet et al. (eds.), Geosciences and Water Resources: Environmental Data Modeling
© Springer-Verlag Berlin Heidelberg 1997