Year: 2025
Type: article
Abstract: This study investigates the relative importance of lower atmospheric versus in situ forcing in driving migrating and nonmigrating diurnal and semidiurnal tides in the thermosphere, as well as the impact of solar and geomagnetic activity on these tides. Our focus is the “thermospheric gap” region 110–250 km, where few observations are available but the tidal spectrum is known to change dramatically. We employ the Hough Mode Extension (HME) fitting approach to the Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere‐ionosphere eXtension (SD‐WACCM‐X) to separate upward‐propagating tides originating from tropospheric and stratospheric sources from those generated in situ within the thermosphere and calculate their ratio to quantify their relative importance. To assess the extent to which the solar and geomagnetic activity impact these thermospheric tides, we compare SD‐WACCM‐X simulations with control simulations in which geomagnetic (Kp) and solar (F10.7) activity are held at lower fixed values. Focusing on the year 2014, a period characterized by elevated solar and geomagnetic variability, we analyze how these external drivers modify tidal amplitudes as a function of latitude and season. The model simulations are validated by comparison with independent neutral density tide observations from the CHAllenging Minisatellite Payload data at approximately 390 km altitude from 2002 to 2004 (F10.7 = 140 sfu). The results highlight the critical role of both thermospheric and lower atmospheric forcings in shaping tidal dynamics, which has implications for forthcoming satellite missions targeting the space weather of the ionosphere‐thermosphere system and improving space operations in the very low Earth orbit.
DOI: 10.1029/2025ja034254
Institution: Clemson University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,070
Awards: G3384445572, G4506539387, G482102745, CAREER: Integrated Studies of Polar Wave and Magnetosphere-Ionosphere-Thermosphere Couplings from New Observations and Whole Atmosphere Modeling, Collaborative Research: CEDAR--Short Wave Infrared Imaging of the Meinel 0-0 Auroral and the Metastable Helium 1083 nm Airglow Emissions for Auroral Physics and Aeronomy Studies, Collaborative Research: ANSWERS: Impacts of Atmospheric Waves and Geomagnetic Disturbances on Quiet-time and Storm-time Space Weather
OpenAlex ID: W4413163111