# Polar Jet Stream Fluctuations in an Energy Balance Model

## TL;DR

This study uses a simplified climate model to analyze how increased greenhouse gases affect the position of the jet stream, revealing initial poleward shifts followed by equatorward movement at higher forcing levels.

## Contribution

It introduces a novel cloud factor function in an energy balance model to simulate eddy-driven jet stream fluctuations under increased radiative forcing.

## Key findings

- Initial poleward shift of jet stream with increased forcing
- Jet stream location becomes quasi-periodic at higher forcing levels
- Mean jet stream position moves equatorward with stronger forcing

## Abstract

We investigate the effect of increased longwave radiative forcing (a proxy for increased greenhouse gas concentration) on the zonally averaged location of the eddy-driven jet stream 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 temperature gradients, to simulate the eddy-driven jet. An increase in longwave radiative forcing initially results in a poleward movement of the jet stream's mean latitude, but as the forcing increases, the location of the jet stream becomes quasi-periodic and its mean location moves equatorward.