"In this proposal we apply to bring Dr. Annika Seppälä to the British Antarctic Survey for a two year IEF, following the award of her PhD at the Finnish Meteorological Institute in October 2007. The aim of the work outlined in this proposal is to follow the effects of energetic particle precipitation into the upper atmosphere, flowing down through the stratosphere, until one can quantify the effect on tropospheric climate, and determine the signature of the forcing in observed climate variability. We do this as part of the ongoing study of non-anthropogenic forcing effects on the Earth’s climate system. The advantage of this proposal is in the match between the scientific objectives identified in this proposal, and the interdisciplinary research undertaken in the host organisation (BAS). Each topic area has an active, internationally renowned group at BAS that will be working closely with the fellow. The influence of solar forcing on the atmosphere is still poorly understood. This is in part due to the multiple mechanisms that link solar output to the Earth’s climate system. In the recent IPCC report most of the estimates of solar forcing were made using models driven by total solar irradiance. However, state-of-the-art research indicates that solar UV and energetic particle precipitation effects are significant in the stratosphere, and thus influencing the global circulation patterns of the Earth. In this project we will use the highest quality polar nighttime observations available of energetic particle forcing of the atmosphere as a result of the descent of nitric oxide into the stratosphere, to answer the questions about the influence of particle precipitation on global circulation patterns. We will bring to bear state-of-the-art models of ionospheric chemistry to interpret the satellite observations and integrate the results with highly regarded reanalysis data, chemistry-transport model, and coupled chemistry-climate model."