Energy Balance Models Incorporating Transport of Thermal and Latent Energy

• Published in: Journal of the atmospheric sciences 1984-02, Vol.41 (3), p.414-421
• Main Author: Flannery, Brian P.
• Format: Article
• Language: English
• ISSN: 0022-4928; 1520-0469
• DOI: 10.1175/1520-0469(1984)041<0414:ebmito>2.0.co;2

Standard latitudinally resolved energy balance models describe conservation of energy on a sphere subject to solar heating, cooling by IR radiation, and diffusive redistribution of energy according to a Fourier-type heat flow with flux proportional to the gradient of temperature. The model determines the distribution of temperature with latitude T(x). The author considers a similar model, the two-phase model, in which transport of both thermal energy of air and latent heat associated with water vapor are incorporated. The two-phase model is used to calculate climate change, i.e., Delta T(x), as a function of varying insolation and changing concentration of atmospheric CO sub(2) under the assumption that relative humidity does not change. The results are compared with calculations from standard energy balance models and general circulation models. The distribution of warming with latitude for doubled atmospheric CO sub(2) found with the two-phase model agrees far better with the pattern of warming found in GCM studies than do results found with the standard model. In particular, the two-phase model, like the GCM, shows greater warming at the poles than at the Equator. In the two-phase model, polar amplification can be explained in terms of a temperature-dependent effective diffusion coefficient that increases with warming. Amplification of warming toward the poles occurs in the two-phase model because the ability of the system to transport heat increases as the system warms.