Polar Jet Stream Fluctuations in an Energy Balance Model

We investigate the effect of increased greenhouse gas concentrations on the zonally averaged extent of the polar cell in a latitude dependent, two-layer Energy Balance Model. The model includes separate terms for atmospheric and surface albedos, and takes into account reflections of shortwave radiation between the surface and atmospheric layers. We introduce the notion of a cloud factor function, which depends on the surface temperature gradient, to simulate the cell structure of Earth's global atmospheric circulation. A simulation of moderately increased greenhouse gas concentrations results in a poleward movement of the polar cell, while larger concentrations drive it toward the equator but obscure its boundary, suggesting large fluctuations in the jet stream.