Circulation and Tides in a Cooler Upper Atmosphere: Dynamical Effects of CO2 Doubling. Issue 10 (21st May 2020)

• Record Type: Journal Article
• Authors: Liu, Huixin; Tao, Chihiro; Jin, Hidekatsu; Nakamoto, Yusuke
• Is Part Of: Geophysical research letters. Volume 47:Issue 10(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-05-21
• Subjects: thermosphere cooling -- thermosphere dynamics -- thermosphere tides -- ionosphere -- vertical coupling -- greenhouse gases; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2020GL087413
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Thermosphere cooling is a known effect of increasing CO2 in the atmosphere. In this study, we explore the changes of thermosphere circulation and tides in the cooled thermosphere via a doubled CO2 numerical experiment using the Ground‐to‐topside Atmosphere Ionosphere model for Aeronomy (GAIA). The results reveal three major features. (1) The thermosphere cools about 10 K more around solstices than equinoxes, more at the summer pole than the winter pole. (2) The meridional circulation shifts downward and strongly accelerates by 5–15 m s −1 . (3) The tidal activity experiences dramatic changes, with a 40–60% reduction in the semidiurnal tides (SW2) throughout the thermosphere but an 30–50% enhancement in diurnal tides (DW1) below 200 km altitude. The nonmigrating tide DE3 has only minor changes. These changes in temperature, meridional circulation, and tides are persistent features in all seasons and can profoundly affect the spatial distribution and diurnal cycles of the ionospheric responses to CO2 doubling via atmosphere composition and electrodynamics. Key Points: Thermosphere cooling is stronger around solstice than equinoxes The meridional circulation is accelerated by 5–15 m/s Semidiurnal tides are strongly reduced