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Paper: Middle Atmosphere Response to Large SEP Events: September 2005 Event
Volume: 484, Outstanding Problems in Heliophysics: From Coronal Heating to the Edge of the Heliosphere
Page: 216
Authors: Verkhoglyadova, O. P.; Wang, S,
Abstract: Solar proton events (SPEs) have been shown to affect chemical balance of the middle atmosphere (from 60 to 90 km in altitude). Solar protons of energies above 10 MeV penetrate deep into the atmosphere temporarily inducing production of chemically active odd hydrogen species (HOx, primarily OH and HO2) which in turn causes ozone (O3) destruction. Latitudinal extend of HOx signature is dependent on the geomagnetic cut-off latitude and changes due to geomagnetic conditions, especially during geomagnetic storms. The Microwave Limb Sounder (MLS) launched onboard Aura satellite in 2004 provides daily simultaneous measurements of HOx, O3 and related parameters such as H2O and temperature on a global scale during both day and night. This is the first time that global measurements of odd hydrogen species are made on a daily basis. We will present an example of a large solar energetic particle (SEP) event of September 2005 and corresponding middle atmospheric signatures. We will demonstrate enhancements in nighttime odd hydrogen density (up to 500%) and decreases in nighttime ozone density (∼ 50%) concomitant with the SEP event. We advocate a study of how different types of SEP events affect composition and dynamics of the middle atmosphere in different latitude and altitude ranges.
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