Forcings in GISS Climate Model

Orbital Forcing

Prior to CMIP5, orbital forcing was not used in transient simulations. In CMIP5, it was included based on calculations of Berger (1978) for both the historical runs and for the last millennium. Changes over recent centuries are small.

Orbital forcings from 850 to 2000 CE

Data for the eccentricity, obliquity and precession for the period 0 CE to 2100 CE can be downloaded here (Schmidt et al., 2011)


Please address inquiries about these data to Dr. Gavin Schmidt.


Berger, A.L., 1978: Long-term variations of daily insolation and Quaternary climatic changes. J. Atmos. Sci., 35, 2362–2367, doi:10.1175/1520-0469(1978)035<2362:LTVODI>2.0.CO;2.

Schmidt, G.A., J.H. Jungclaus, C.M. Ammann, E. Bard, P. Braconnot, T.J. Crowley, G. Delaygue, F. Joos, N.A. Krivova, R. Muscheler, B.L. Otto-Bliesner, J. Pongratz, D.T. Shindell, S.K. Solanki, F. Steinhilber, and L.E.A. Vieira, 2011: Climate forcing reconstructions for use in PMIP simulations of the last millennium (v1.0). Geosci. Model Dev., 4, 33-45, doi:10.5194/gmd-4-33-2011.

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This page was written by Dr. Gavin Schmidt.

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