10/31/2023
By Lynne Schaufenbil
Committee: Timothy Cook, Supriya Chakrabarti, and Peter Bender
Title: Airglow as seen by LITES
Abstract: The ionosphere is a dynamic and inhomogeneous region of plasma which can absorb, emit, and scatter radio wave signals located between 80-1000 km in the Earth’s atmosphere. As a result, radio-communication systems, wireless computer networks, global positioning system, and other similarly designed forms of communication suffer most of their errors due to interactions with the ionosphere, making it a particularly important subject of study. Analysis of airglow provides such insight into properties of the ionosphere. During daytime (dayglow), the Sun’s photons ionize the molecules in the upper atmosphere which creates the plasma of the ionosphere; then, during nighttime (nightglow), the same ions undergo a recombination process by colliding with free electrons. In this environment, Airglow data is collected by the Limb-Imaging Ionospheric and Thermospheric Extreme-Ultraviolet Spectrograph Limb-Imaging Ionospheric and Thermospheric Extreme-Ultraviolet Spectro- graph (LITES). LITES is a high-throughput, single optical element spectrograph which im- ages one-dimensional altitude profiles of the ionosphere and thermosphere above the limb of the Earth. Airglow data from LITES is used to generate intensity time-series of various spectral lines associated with specific ions including singly ionized oxygen (834 Å), hydro- gen (1216 Å), and neutral oxygen (1304 Å and 1356 Å). This thesis focuses on determining the accuracy and reliability of LITES data by means of a comparative analysis using two essential parameter combinations: latitude-longitude and time-AST. Latitude-longitude plots demonstrated the instrument’s ability to accurately capture significant atmospheric features like the South Atlantic Anomaly (SAA) and equatorial arcs. The time-AST plots provided insights into each spectral line’s behavior throughout orbits and daily cycles, revealing dis- tinct data gap patterns, a diurnal peak line intensity variation linked to the International Space Station (ISS)’s orbital precession, and unique behaviors for each spectral feature, enriching our understanding of ionospheric and Thermospheric dynamics.