the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 18 Aug 2026
Impact of Super Typhoon Yagi on Earth’s Atmosphere: from Troposphere to Thermosphere/Ionosphere
Abstract. Typhoons can generate gravity waves that transport energy and momentum from the lower atmosphere to the upper atmosphere, but the spectral characteristics and vertical coupling pathways of these disturbances remain incompletely understood. We investigate the atmospheric response to Super Typhoon Yagi (2024) by a Mesosphere-Stratosphere-Troposphere (MST) radar, two BeiDou Navigation Satellite System (BDS) receivers, and ERA5 reanalysis data. Great wind disturbances were observed in the troposphere and lower stratosphere by the MST radar, as Yagi passed approximately 188 km south of it. Gravity-wave activity was strongest between 5–12 km altitude and was dominated by periods of 0.6–5 h, with the maximum absolute momentum flux reaching 1.98 m2 s-2. ERA5 temperature perturbations revealed concentric wave structures centered near the typhoon eye, with amplitudes increasing from approximately 0.7 K at 20 km to more than 2 K at 50 km altitude. In mesosphere and lower thermosphere, enhanced and mutually consistent oscillations in the zonal, meridional, and vertical winds appeared on 7 Sept., with a dominant period near 2.0 h. Nearly simultaneous disturbances with a dominant period of approximately 2.1 h were detected in the total electron content of two BDS receivers. These observations provide evidence of typhoon-related disturbances extending from troposphere to thermosphere/ionosphere.
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Status: open (until 14 Oct 2026)
- RC1: 'Comment on egusphere-2026-4680', Ravindra Pratap Singh, 11 Sep 2026 reply
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RC2: 'Comment on egusphere-2026-4680', Anonymous Referee #2, 12 Sep 2026
reply
Peer Review of “Impact of Super Typhoon Yagi on Earth’s Atmosphere: from Troposphere to Thermosphere/Ionosphere”
Overall recommendation: Major Revision
This manuscript presents an interesting multi-instrument observational study of the atmospheric response to Super Typhoon Yagi (2024), combining three-dimensional wind observations from the CLAIR MST radar, ERA5 temperature fields, and BDS/GNSS TEC measurements.
The observational opportunity is valuable. In particular, the ability of CLAIR to provide three-dimensional wind observations in both the lower atmosphere and MLT region during the passage of a strong typhoon is potentially an important contribution. The identification of approximately 2 h oscillations in all three wind components in the MLT region on 7 September, together with approximately 2.1 h oscillations in two geographically separated TEC measurements, is intriguing. The manuscript also makes a useful attempt to connect observations at different atmospheric heights.
The authors report strong lower-atmospheric disturbances, with the largest gravity-wave activity occurring approximately between 5–12 km and a maximum absolute momentum flux of 1.98 m² s⁻². They then identify wave activity in the 0.6–4.5 h range in the troposphere and lower stratosphere, approximately 2 h activity in the MLT region, and approximately 2.1 h TEC oscillations.
However, the central scientific conclusion is stronger than what the present analysis appears to demonstrate.
In particular, I am not yet convinced that the manuscript has demonstrated vertical propagation of the same gravity-wave disturbance from Yagi into the MLT and subsequently into the ionosphere. The observations demonstrate temporal associations that are consistent with such a scenario, but establishing the propagation pathway and causality requires additional analysis and/or substantially more cautious interpretation.
I believe the paper could become a valuable contribution if the authors strengthen the spectral methodology, quantify significance and uncertainty, and appropriately distinguish between evidence consistent with vertical coupling and demonstration of vertical coupling.
Major Comments
- The central claim of vertical coupling is not sufficiently demonstrated
The manuscript essentially constructs the following chain:
Typhoon → tropospheric GW activity → stratospheric GW activity → MLT ~2 h wave → ionospheric ~2.1 h TEC disturbance.
The individual observations are interesting, but the manuscript currently does not establish that these are necessarily the same propagating wave.
For example, the tropospheric/stratospheric analysis identifies disturbances over approximately 0.6–4.5 h, whereas the MLT disturbance is concentrated near ~2 h and the TEC disturbance near ~2.1 h. The authors interpret the narrowing of the spectrum with altitude as evidence of progressive filtering.
That is physically plausible, but stronger argument would be to show the correlation in other characteristics like:
- horizontal propagation information;
- background wind information (cross-spectral analysis, see Lu et al. (2005));
- consistency of horizontal wavelength/direction;
- or comparison with a gravity-wave propagation model.
At present, the manuscript mainly establishes spectral similarity and temporal coincidence.
I therefore recommend changing statements such as:
“We track the spectrum variations of the typhoon associated GWs from troposphere to thermosphere/ionosphere”
and
“The GWs with a dominant period of 2 h that ultimately reach ionospheric heights”
to more cautious formulations unless additional propagation evidence can be provided.
- The signal-processing procedure may substantially influence the reported wave spectrum
The authors apply several sequential processing operations, including:
- sliding-window denoising;
- running-mean removal;
- Butterworth band-pass filtering;
- interpolation;
- additional running averaging;
- LOESS detrending;
- thresholding;
- wavelet analysis.
For example, for the troposphere/stratosphere, a 25-point running mean is removed before applying the 0.6–5 h band-pass filter.
The radar temporal resolution is 15 min. Therefore:
25 points × 15 min = 375 min = 6.25 h.
Consequently, the preprocessing itself contains a characteristic timescale that is close to—and actually longer than—the upper limit of the subsequent 0.6–5 h analysis band.
This does not automatically invalidate the result, but the authors need to demonstrate that the preprocessing does not artificially enhance, suppress, or reshape the 0.6–5 h spectrum.
I strongly recommend showing:
- the original time series;
- the background component;
- the residual after background removal;
- the result after band-pass filtering;
- the wavelet spectrum.
The authors should also provide the exact Butterworth filter order and implementation details, including whether the filter is applied forward/backward and how the boundaries are handled.
This is particularly important because the paper's main physical conclusion depends heavily on the spectral evolution with altitude.
Minor Comments
- The conclusion contains: “These observations will deep our understanding…” This should be: “These observations will deepen our understanding…”
- In Figure 2 the F10.7 and Kp information is useful, but the authors should explicitly discuss whether the observed ionospheric period could be affected by background solar/geomagnetic variability.
- In Figure 10 the raw TEC, detrended TEC, thresholded TEC, and final residual would be much more informative than showing only the processed product.
Strengths of the Manuscript
- Excellent observational opportunity
- Multi-instrument approach
- Three-dimensional wind observations
- The MLT result is genuinely interesting
Citation: https://doi.org/10.5194/egusphere-2026-4680-RC2
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Please find the attached PDF file for my comments.