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Statistical Structure of Nighttime O 2 Aurora From SABER and Its Dependence on Geomagnetic and Solar Activities in Winter
Author(s) -
Gao Hong,
Xu Jiyao,
Chen GuangMing,
Zhu Yajun,
Liu Weijun,
Wang Chi
Publication year - 2020
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028302
Subject(s) - airglow , intensity (physics) , emission intensity , earth's magnetic field , atmospheric sciences , thermosphere , depth sounding , volume (thermodynamics) , atmosphere (unit) , physics , solar wind , ionosphere , geophysics , meteorology , optics , plasma , geology , magnetic field , luminescence , oceanography , quantum mechanics
O 2 aurora is one kind of important molecular aurorae that is not fully understood yet. It is hard to be investigated due to the contamination by nightglow. In this work, we studied O 2 aurora based on the observations of O 2 emission at 1.27 μm from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument during the nighttime over 18 years. The horizontal structure of O 2 auroral zone is given for the first time, and the vertical profile of O 2 auroral volume emission rate is obtained after removing O 2 nightglow contamination. The O 2 auroral intensity and the peak height and peak volume emission rate of the vertical profile averaged over the O 2 auroral zone are studied in detail. For Kp Levels 1–5, the O 2 auroral peak height varies between 104 and 112 km and is negatively correlated with the auroral intensity and peak volume emission rate. The O 2 auroral intensity varies between 0.14 and 5.97 kR, and the peak volume emission rate varies between 0.97 × 10 2 and 41.01 × 10 2 photons cm −3 s −1 . Furthermore, the dependences of the O 2 aurora on geomagnetic and solar activities are analyzed. The O 2 auroral intensity and peak volume emission rate exponentially increases with increasing Kp index, whereas the peak height decreases with increasing Kp index. The O 2 auroral intensity and peak volume emission rate under solar minimum condition are larger than those under solar maximum condition. The peak height under solar minimum condition is lower than that under solar maximum condition.