The investigators will continue using a Fabry-Perot interferometer for systematic studies of variability of faint exospheric hydrogen Balmer-alpha emission intensity due to solar and other natural influences. The instrument is called WHAM for Wisconsin H-Alpha Mapper, and is located at the Kitt Peak Observatory in Tucson, Arizona. The sun plays a major role in defining the base properties of the upper atmosphere. Its influence through heating and photochemistry must be understood to accurately characterize the upper atmosphere and to separate natural from possible anthropogenic signatures in this region. The observations made with WHAM will lead to improved understanding of natural variability in upper and middle atmospheric hydrogenous species, thereby facilitating more detailed predictions for their response to anthropogenic increases in greenhouse gases.
