View in EDS

Gravity Wave Influences on MSTID Climatology Over CONUS: WACCM‐X Year‐Long Simulation and GNSS Long‐Term Observation.

Saved in:
Bibliographic Details
Title: Gravity Wave Influences on MSTID Climatology Over CONUS: WACCM‐X Year‐Long Simulation and GNSS Long‐Term Observation.
Authors: Liu, Jing1 (AUTHOR) jingl90@mit.edu, Zhang, Shun‐Rong1 (AUTHOR), Liu, Hanli2 (AUTHOR), Coster, Anthea J.1 (AUTHOR), Erickson, Philip J.1 (AUTHOR)
Source: Journal of Geophysical Research. Space Physics. Jun2026, Vol. 131 Issue 6, p1-16. 16p.
Subject Terms: *Ionosphere, Gravity waves, Ionospheric disturbances, Global Positioning System, Atmospheric models
Geographic Terms: United States
Abstract: Medium‐Scale Traveling Ionospheric Disturbances (MSTIDs) are prominent wave‐like structures in the ionosphere, with complex generation mechanisms involving both atmospheric gravity waves (GWs) and electrodynamic instabilities such as the Perkins instability (PI). This study aims to understand the observed MSTID climatology, especially to clarify the impact of GWs on MSTID excitation and propagation over the continental United States (CONUS). Year‐long high‐resolution simulations from the latest version of the Whole Atmosphere Community Climate Model with thermosphere/ionosphere extension (WACCM‐X) are compared with GNSS‐based MSTID climatology deduced from the extensive Madrigal database. Our results indicate good consistency between the model and data in key features of MSTID climatology, including the diurnal and seasonal patterns of occurrence rate and propagation direction, particularly the dominant daytime southward/southeastward propagation. This highlights the fundamental influence of GWs, as these WACCM‐X waves are driven by GW forcing from below. However, some discrepancies exist, especially in the nighttime occurrence rates and propagation directions, which are partially due to limitations in the model's representation of GW sources, background winds, and other non‐GW regional factors. These nighttime MSTID climatological features over CONUS are inconsistent with the anticipated PI effects either (e.g., southwestward propagation) implying that the actual generation involves mixed processes where PI effects may not be dominant and GWs can still contribute. These findings advance our understanding of MSTID generation mechanisms and offer valuable insights for improving ionospheric modeling and forecasting. Plain Language Summary: We studied upper atmospheric medium‐scale wave‐like perturbations over the continental United States (CONUS) using WACCM‐X model simulations and Global Navigation Satellite System observations. By using computer simulations and satellite data, we examined when and how these waves appear. Our method allowed us to closely compare the model and observations. We found that the model does a good job of reproducing the main patterns seen in the observations, especially during the day, when the observed ionospheric waves mostly move southward or southeastward, matching what is simulated for changes in the neutral atmosphere. This suggests that changes in the neutral atmosphere are the main cause of these ionospheric waves in the United States. However, there are still a few differences, especially at night, likely because additional physical processes such as ionospheric electrodynamics and/or other wave sources are involved. The model does not fully capture the main characteristics of these waves at night, suggesting that the above additional processes need to be considered, although electrodynamic effects are less significant in CONUS than in some other regions. We also note that differences in Earth's magnetic field may affect the occurrence rate of the ionospheric waves. This work helps us better understand what generates these waves and can improve future predictions. Key Points: WACCM‐X simulations are employed to understand the gravity wave impact on observed MSTID climatology over CONUSGravity waves are identified as the main driver of MSTIDs, with WACCM‐X capturing key diurnal and seasonal patternsNighttime MSTIDs over CONUS likely result from mixed processes, including Perkins instability [ABSTRACT FROM AUTHOR]
Copyright of Journal of Geophysical Research. Space Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: GreenFILE
Description
Abstract:Medium‐Scale Traveling Ionospheric Disturbances (MSTIDs) are prominent wave‐like structures in the ionosphere, with complex generation mechanisms involving both atmospheric gravity waves (GWs) and electrodynamic instabilities such as the Perkins instability (PI). This study aims to understand the observed MSTID climatology, especially to clarify the impact of GWs on MSTID excitation and propagation over the continental United States (CONUS). Year‐long high‐resolution simulations from the latest version of the Whole Atmosphere Community Climate Model with thermosphere/ionosphere extension (WACCM‐X) are compared with GNSS‐based MSTID climatology deduced from the extensive Madrigal database. Our results indicate good consistency between the model and data in key features of MSTID climatology, including the diurnal and seasonal patterns of occurrence rate and propagation direction, particularly the dominant daytime southward/southeastward propagation. This highlights the fundamental influence of GWs, as these WACCM‐X waves are driven by GW forcing from below. However, some discrepancies exist, especially in the nighttime occurrence rates and propagation directions, which are partially due to limitations in the model's representation of GW sources, background winds, and other non‐GW regional factors. These nighttime MSTID climatological features over CONUS are inconsistent with the anticipated PI effects either (e.g., southwestward propagation) implying that the actual generation involves mixed processes where PI effects may not be dominant and GWs can still contribute. These findings advance our understanding of MSTID generation mechanisms and offer valuable insights for improving ionospheric modeling and forecasting. Plain Language Summary: We studied upper atmospheric medium‐scale wave‐like perturbations over the continental United States (CONUS) using WACCM‐X model simulations and Global Navigation Satellite System observations. By using computer simulations and satellite data, we examined when and how these waves appear. Our method allowed us to closely compare the model and observations. We found that the model does a good job of reproducing the main patterns seen in the observations, especially during the day, when the observed ionospheric waves mostly move southward or southeastward, matching what is simulated for changes in the neutral atmosphere. This suggests that changes in the neutral atmosphere are the main cause of these ionospheric waves in the United States. However, there are still a few differences, especially at night, likely because additional physical processes such as ionospheric electrodynamics and/or other wave sources are involved. The model does not fully capture the main characteristics of these waves at night, suggesting that the above additional processes need to be considered, although electrodynamic effects are less significant in CONUS than in some other regions. We also note that differences in Earth's magnetic field may affect the occurrence rate of the ionospheric waves. This work helps us better understand what generates these waves and can improve future predictions. Key Points: WACCM‐X simulations are employed to understand the gravity wave impact on observed MSTID climatology over CONUSGravity waves are identified as the main driver of MSTIDs, with WACCM‐X capturing key diurnal and seasonal patternsNighttime MSTIDs over CONUS likely result from mixed processes, including Perkins instability [ABSTRACT FROM AUTHOR]
ISSN:21699380
DOI:10.1029/2025JA034983