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SABER Observation of Storm‐Time Hemispheric Asymmetry in Nitric Oxide Radiative Emission
Author(s) -
Bag Tikemani,
Li Zheng,
Rout Diptiranjan
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028849
Subject(s) - thermosphere , atmospheric sciences , geomagnetic storm , ionosphere , equinox , radiative transfer , storm , zonal and meridional , mesosphere , atmosphere (unit) , asymmetry , environmental science , physics , earth's magnetic field , climatology , geophysics , stratosphere , geology , meteorology , quantum mechanics , magnetic field
The nitric oxide (NO) 5.3 μm radiative emission is the dominating and most efficient cooling agent in the thermosphere above 100 km. The NO 5.3 μm radiative cooling is an important parameter, particularly during geomagnetic storm events, to quantify the energy budget within the magnetosphere‐ionosphere‐thermosphere system. We utilize the TIMED (Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics)/SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) observations of NO radiative cooling to investigate the storm‐time hemispheric asymmetry during 2002–2018. The auxiliary parameters such as NO density, atomic oxygen density, thermospheric temperature, and the meridional wind are obtained from the TIEGCM (Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model) simulations. We analyze the events that occurred close to (or during) the equinox periods to get rid of the effect of seasonal asymmetry. The TIEGCM‐simulated NO density and meridional wind show hemispheric asymmetry during geomagnetic storm event. Almost no hemispheric variation in TIEGCM‐atomic oxygen and ‐thermospheric temperature is noticeable. The SABER‐observed and the TIEGCM‐simulated radiative flux exhibits higher values in the northern and southern hemispheres, respectively, during the events close to (or during) March and September equinox. Our analysis shows that the storm‐time meridional wind could play an important role resulting in the hemispheric asymmetry by changing the density and temperature.