On the Variation of Column $O/Ntextsubscript{2} $ in the upper atmosphere using Principal Component Analysis in 2-dimensional images Journal Article uri icon

Overview

abstract

  • Day-to-day variability in thermospheric composition is driven by solar,; geomagnetic and meteorological drivers. The ratio of the column density; of atomic oxygen and molecular nitrogen; (O/Ntextsubscript{2}) is a useful parameter for; quantifying this variability that has been shown to exhibit close; correspondence to F-region electron density, total electron content and; upper atmospheric transport. Therefore, understanding the variability in; O/Ntextsubscript{2} gives an insight into the; geophysical variability of other relevant ionospheric and thermospheric; parameters. The relative contributions of these drivers for; thermospheric variability is not well known. Here we report a new; analysis of the variability in O/Ntextsubscript{2} to; identify the sources of variability in a 55-day time period. Principal; Component Analysis (PCA) was performed on thermospheric; O/Ntextsubscript{2} column density ratio from days 81; to 135 of 2020 from NASA’s Global-scale Observations of the Limb and; Disk (GOLD) mission. We find that geomagnetic activity is the major; source of variability in O/Ntextsubscript{2} column; density ratio, followed by solar-driven transport and meteorological; driving from the lower atmosphere. The first component (PC1) showed a; strong correlation to Kp index and IMF, and geomagnetic storm effects; are seen in the wavelet analysis of PC1’s weights. The fifth component; (PC5) showed a strong quasi-6-day oscillation(Q6DO). The higher; explained variance ratio of PC1 suggests a stronger effect of; geomagnetic activity relative to meteorological forcing from planetary; scale waves. The methodology of the present study also demonstrates how; PCA can be used to isolate and rank different sources of variability in; other IT parameters.

publication date

  • September 27, 2022

has restriction

  • hybrid

Date in CU Experts

  • September 30, 2022 7:51 AM

Full Author List

  • Goel D; Wu Y-JJ; Harding BJ; Triplett C; Immel TJ; Chihoko C; England SL

author count

  • 7

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