image: In spring, southeastward propagating events are scarce at Dandong due to strong eastward background winds, while Lhasa exhibits similar directional constraints. During summer, both stations are dominated by northeastward propagating AGWs, influenced by southwestward wind fields. Autumn shows divergent source mechanisms: events at Dandong primarily originate from wind shear, whereas Lhasa's waves are triggered by convective weather, with source locations determining propagation trends. Winter features predominant southwestward propagation at Dandong under eastward wind influence, while Lhasa's southeastward trend may result from secondary wave generation, requiring further investigation.
Credit: Beijing Zhongke Journal Publising Co. Ltd.
This research was led by Prof. Chang Lai and collaborators from the National Space Science Center. The team analyzed 979,743 airglow images from the Chinese Meridian Project, identifying 519 AGW events—317 at Dandong and 202 at Lhasa—using a machine learning-based detection model.
The study revealed contrasts in AGW characteristics between the two sites. At Dandong, waves exhibited longer horizontal wavelengths (35–50 km), periods of 14–20 minutes, and higher relative intensities (0.4–0.6%). In contrast, AGWs at Lhasa had shorter wavelengths (10–30 km), faster propagation speeds (40–100 m/s), and lower intensities (0.1–0.3%).
Seasonal occurrence rates also differed significantly. Dandong experienced peaks in both summer and winter, while Lhasa showed only a winter peak. "The absence of a summer peak at Lhasa is likely due to fewer convective weather events," Chang Lai says.
Propagation directions were strongly influenced by wind-field filtering effects. In summer, northeastward waves dominated at both sites. In winter, Dandong saw predominantly southwestward propagation, whereas Lhasa’s waves shifted southeastward—a trend potentially linked to secondary wave generation.
Backward ray-tracing analysis traced 63% of Dandong’s events to tropospheric sources (below 13 km), compared to only 20% at Lhasa. Convection and wind shear were identified as primary triggers.
See the article:
Comparative Study Reveals Seasonal Characters of Atmospheric Gravity Waves in Dandong and Lhasa
http://doi.org/10.26464/epp2026002
Journal
Earth and Planetary Physics
Article Title
Comparison of atmospheric gravity wave event statistics between Dandong and Lhasa
Article Publication Date
10-Jan-2026