skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Modulation of Thermospheric Circulation by Lower‐Thermospheric Winter‐to‐Summer Circulation: The Atmosphere Gear Effect
Title: Modulation of Thermospheric Circulation by Lower‐Thermospheric Winter‐to‐Summer Circulation: The Atmosphere Gear Effect
This study investigates the impact of the lower‐thermospheric winter‐to‐summer circulation on the thermosphere's thermal structure and meridional circulation. Using NCAR TIE‐GCM, we compare simulations with and without the lower‐thermospheric circulation, finding that its inclusion enhances summer‐to‐winter thermospheric circulation by 40% in the summer hemisphere but decelerates it in the winter thermosphere. Meanwhile, vertical wind exhibits stronger upward motion ±30 degree latitude above 10e−6 hPa (174 km) when lower‐thermospheric circulation is incorporated. This dynamic coupling functions as an atmospheric “gear mechanism,” accelerating momentum and energy transfer to higher altitudes. Including lower‐thermospheric circulation improves agreement between the nudged run and NRLMSIS 2.1 in intra‐annual variability (IAV) of mass density. This suggests lower‐thermospheric circulation is a key factor in modulating IAV in the coupled thermosphere‐ionosphere system. This study reveals a new coupling mechanism between the lower atmosphere, thermosphere, and ionosphere, with significant implications for understanding upper‐atmospheric dynamics and improving space weather models.  more » « less
Award ID(s):
2409172
PAR ID:
10600907
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
American Geophysical Union
Date Published:
Journal Name:
Geophysical Research Letters
Volume:
52
Issue:
10
ISSN:
0094-8276
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. (, Zenodo)
    TIE-GCM model output used in the study “Modulation of Thermospheric Circulation by Lower-Thermospheric Winter-to-Summer Circulation: The Atmospheric Gear Effect” (Wang et al., 2025). This dataset includes key variables used to analyze the dynamic and thermodynamic coupling between the lower thermosphere and mesosphere. 
    more » « less
  2. ; ; ; ; ; ; (, Journal of Geophysical Research: Space Physics)
    Abstract Using theHighattitude Interferometer WIND observation balloon and Antarctic Jang Bogo station high latitude conjugate observations of the thermospheric winds we investigate the seasonal and hemispheric differences between the northern and southern hemispheres in June 2018. We found that the summer (northern) hemisphere dayside meridional winds have a double‐hump feature, whereas in the winter (southern) hemisphere the dayside meridional winds have a single hump feature. We attribute that to stronger summer, perhaps, northern hemisphere cusp heating. We also compared the observation with NCAR Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) model. The TIEGCM reproduced the double‐hump feature because of added cusp heating. The summer hemisphere has stronger anti‐sunward winds. This is the first time we have very high latitude conjugate thermospheric wind observations. 
    more » « less
  3. ; ; ; ; ; (, Journal of Geophysical Research: Space Physics)
    Recent evidence has revealed that strong coupling between the lower atmosphere and the thermosphere (100 km) occurs on intra‐seasonal (IS) timescales ( 30–90 days). The Madden‐Julian Oscillation (MJO), a key source of IS variability in tropical convection and circulation, influences the generation and propagation of atmospheric tides and is believed to be a significant driver of thermospheric IS oscillations (ISOs). However, limited satellite observations in the “thermospheric gap” (100–300 km) and challenges faced by numerical models in characterizing this region have hindered a comprehensive understanding of this connection. This study uses an Ionospheric Connection Explorer (ICON)‐adapted version of the Thermosphere Ionosphere Electrodynamics General Circulation Model, incorporating lower boundary tides from Michelson Interferometer for Global High‐resolution Thermospheric Imaging (MIGHTI) observations, to quantify the impact of the upward‐propagating tidal spectrum on thermospheric ISOs and elucidate connections to the MJO. Thermospheric zonal and diurnal mean zonal winds exhibit prominent ( 20 m/s) tidally driven ISOs throughout 2020–2021, largest at low latitudes near 110–150 km altitude. Correlation analyses confirm a robust connection between thermospheric ISOs, tides, and the MJO. Additionally, Hovmöller diagrams show eastward tidal propagation consistent with the MJO and concurrent Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) observations. This study demonstrates that vertically propagating tides play a crucial role in linking IS variability from the lower atmosphere to the thermosphere, with the MJO identified as a primary driver of this whole‐atmosphere teleconnection. Understanding these connections is vital for advancing our knowledge in space physics, particularly regarding the dynamics of the upper atmosphere and ionosphere 
    more » « less
  4. ; (, Journal of Geophysical Research: Space Physics)
    Abstract Effects of Hurricane Grace in August 2021 are studied in the thermosphere and ionosphere, using data from the COSMIC‐2, ICON, and GOLD satellites. Significant impacts on electron density, thermospheric winds, and temperature are observed after the onset of the hurricane, compared to the pre‐hurricane phase. Comparison of the observations during the hurricane with the ones during a non‐hurricane year clearly provides further evidence for substantial hurricane‐induced thermospheric and ionospheric changes. We reveal an enhancement in electron density during the hurricane's rapid intensification and pronounced changes in thermospheric winds. Additionally, the low‐latitude thermosphere exhibits considerable warming of up to 70 K around 150 km during this period. These changes highlight the long‐range vertical coupling mechanisms between hurricanes and the upper atmosphere, and provide valuable insights into the profound influence of meteorological events on upper atmospheric dynamics, emphasizing the need for further exploration. 
    more » « less
  5. ; (, Scientific Reports)
    Abstract Nitric oxide (NO) emission via 5.3 µm wavelength plays dominant role in regulating the thermospheric temperature due to thermostat nature. The response of NO 5.3 mm emission to the negative pressure impulse during November 06–09, 2010 is studied by using Sounding of Atmosphere by Broadband Emission Radiometry (SABER) observations onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite and model simulations. The TIMED/SABER satellite observations demonstrate a significant enhancement in the high latitude region. The Open Geospace General Circulation Model (OpenGGCM), Weimer model simulations and Active Magnetosphere and Planetary Electrodynamics Response Experiment measurements exhibit intensification and equatorward expansion of the field-aligned-currents (FACs) post-negative pressure impulse period due to the expansion of the dayside magnetosphere. The enhanced FACs drive precipitation of low energy particle flux and Joule heating rate affecting whole magnetosphere–ionosphere–thermosphere system. Our study based on electric fields and conductivity derived from the EISCAT Troms$${\o }$$ ø radar and TIEGCM simulation suggests that the enhanced Joule heating rate and the particle precipitations prompt the increase in NO cooling emission. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Text Encoded Conversion
  • XML
  • Save / Share this Record
  • Send to Email