Ultraviolet Occultations: An Essential Technique for Bridging the Thermospheric Gap
In this seminar, I present recent scientific findings using far and extreme ultraviolet (FUV and EUV) solar and stellar occultations and make the case that this seemingly overlooked technique has the potential to address a number of questions of upmost importance to the heliophysics community. Solar and stellar ultraviolet occultations provide a capability essential for advancing our understanding of the thermosphere and its coupling with the ionosphere and lower atmosphere. Advances over the past decade have demonstrated the power of occultations for measuring gravity waves and tides over large altitude ranges and across atmospheric domains. Additionally, occultation instruments measure neutral density in the thermosphere directly using technology that is readily miniaturized, making them ideal candidates for space weather monitoring sensors. Recent advances in thermospheric science demonstrated with “bonus-science” solar occultation measurements (made by instruments intended to study the Sun) have led NASA to fund the Occultation Wave Limb Sounder (OWLS), the first satellite instrument designed for solar occultations of the thermosphere. Future missions for studying the thermosphere should include instruments specifically designed for occultations to maximize the quality of science measurements.
Dr. Ed Thiemann is a research scientist at LASP focusing on extreme ultraviolet instrumentation for solar irradiance and solar occultations. His PhD work focused on solar irradiance modeling using the Extreme Ultraviolet Monitor onboard the MAVEN mission, which has been studying Mars’s upper atmosphere and space environment since 2014. After defending his PhD in 2016, his research began to focus on using the solar extreme ultraviolet spectrum to probe planetary upper atmospheres and he has created new datasets of thermospheric density at Earth and Mars using solar EUV photometers. Currently, he is developing additional datasets of Earth’s thermosphere and exosphere using instruments intended for studying the Sun, and instrumentation for the next generation of upper atmosphere measurements. His current NASA flight instrument responsibilities include being the PI of the Occultation Wave Limb Sounder (OWLS) instrument and the Deputy PI of the MAVEN EUV Monitor (EUVM).