Simple energy balance model resolving the seasons and the continents - Application to the astronomical theory of the ice ages

• Main Authors: North, G. R., Short, D. A., Mengel, J. G.
• Format: Other/Unknown Material
• Language: unknown
• Published: 1983
• Subjects: 46; Ice cap
• Online Access: http://ntrs.nasa.gov/search.jsp?R=19830061623

An analysis is undertaken of the properties of a one-level seasonal energy balance climate model having explicit, two-dimensional land-sea geography, where land and sea surfaces are strictly distinguished by the local thermal inertia employed and transport is governed by a smooth, latitude-dependent diffusion mechanism. Solutions of the seasonal cycle for the cases of both ice feedback exclusion and inclusion yield good agreements with real data, using minimal turning of the adjustable parameters. Discontinuous icecap growth is noted for both a solar constant that is lower by a few percent and a change of orbital elements to favor cool Northern Hemisphere summers. This discontinuous sensitivity is discussed in the context of the Milankovitch theory of the ice ages, and the associated branch structure is shown to be analogous to the 'small ice cap' instability of simpler models.