Work

Equinox Transitions of Thermosphere O/N2 and Meridional Circulation in the Northern Hemisphere as Observed by NASA's GOLD and ICON Missions

Year: 2024

Type: article

Abstract: Leveraging the unique perspective enabled by Global‐scale Observations of the Limb and Disk, we examined the characteristics of equinox transitions in the thermospheric column integrated ratio of atomic oxygen to molecular nitrogen (O/N2) in the Northern Hemisphere. We found that the timing of the O/N2 equinox transition from winter to summer or vice versa exhibits a progression with latitude, particularly, near spring equinox. The O/N2 equinox transition is far slower during spring compared to fall, leading to a remarkable seasonal asymmetry. Ionospheric Connection Explorer observed a prominent asymmetry in the summer‐to‐winter circulation in the middle to upper thermosphere, implying that the inter‐hemispheric circulation plays a crucial role in the O/N2 equinox transition. Additionally, since the wave‐driven meridional circulation in the lower thermosphere displays a seasonal asymmetry between the northward‐to‐southward and southward‐to‐northward transitions, we would anticipate that the O/N2 equinox transition is also influenced by the lower atmospheric forcing.

Source: Geophysical Research Letters

DOI: 10.1029/2024gl111810

Authors: Q. Gan, L. Qian, N. M. Pedatella, R. W. Eastes

Institutions: University of Colorado Boulder, Laboratory for Atmospheric and Space Physics, NSF National Center for Atmospheric Research, NSF NCAR High Altitude Observatory

Language: English

Topic: Ionosphere and magnetosphere dynamics

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $2,900