Analysis on Multi-Factor Synergistic Hazards Mechanism of Wet Micro-downburst: Multi-Source Data Fusion Analysis based on Passenger Ship Capsizing Accident in Qianxi Region, Guizhou on May 4<sup>th</sup>, 2025

Wu, Ankun; Guo, Xi; Yao, Dan; Du, Xiaoling; He, Dongpo; Li, Jue; Jin, Shisheng; Bai, Tienan

doi:10.5194/egusphere-2025-4293

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https://doi.org/10.5194/egusphere-2025-4293

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26 Sep 2025

| 26 Sep 2025

Status: this preprint is open for discussion and under review for Natural Hazards and Earth System Sciences (NHESS).

Analysis on Multi-Factor Synergistic Hazards Mechanism of Wet Micro-downburst: Multi-Source Data Fusion Analysis based on Passenger Ship Capsizing Accident in Qianxi Region, Guizhou on May 4^th, 2025

Ankun Wu, Xi Guo, Dan Yao, Xiaoling Du, Dongpo He, Jue Li, Shisheng Jin, and Tienan Bai

Abstract. To reveal the multi-factor synergistic hazards mechanism of downbursts, this study takes the passenger ship capsizing accident at Dongfeng Reservoir in Qianxi, Guizhou Province around 08:32 (UTC) on May 4, 2025 ("May 4" accident) as the research object, and utilizes the data of integrates radar, ground observation, lightning monitoring, video and on-site disaster trace data to systematically analyze the hazard process of wet microburst. A strong persistence intense radar echoes (≥60 dBZ) was observed over the incident area. At 08:29 (UTC), the core intense echoes broke through the zero-degree layer and rapidly descended from 6–8 km to 2–4 km, which synchronized with the strongest downdraft, accompanied by localized high differential reflectance at 2–4 km showed a local high value R > 2 dB) . After the intense echoes touched the ground, an explosive near-surface divergent flow field was triggered: wind speed surged from 0.8 m/s to 34.7 m/s within 6 minutes, temperature dropped by 14.9 °C in 10 minutes, and air pressure jumped by 5.4 hPa in 5 minutes, and cumulative rainfall reached 40.6 mm. Lightning activity was dominated by cloud flashes (85.1 %), with high-density areas coincided with convective paths. The phase transition of ice particles (indicated by ZDR) intensified downdrafts through "mass loading – cooling enhancement effect" feedback, which triggered wind direction reversal and the occurrence of hailfall. The distribution of disaster traces (directional lodging, quadrant-switching damage) spatial-temporal matched with the wind field evolution, which verifying the coupling disaster-causing mechanism of dynamic attenuation and microphysical transport.

Received: 02 Sep 2025 – Discussion started: 26 Sep 2025

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Ankun Wu, Xi Guo, Dan Yao, Xiaoling Du, Dongpo He, Jue Li, Shisheng Jin, and Tienan Bai

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RC1:
'Comment on egusphere-2025-4293', Anonymous Referee #1, 16 Oct 2025 reply
Summary: The paper presents valuable multi-source observations of a severe wet microburst, but readability suffers from long, nested sentences and mixed presentation of results and interpretation. The authors should either combine Results and Discussion, OR retain separate sections by limiting Results to data and moving interpretations to Discussion, ending with a clear take-home message on implications for severe convection warning and hazard mitigation.
Abstract
It could more explicitly state the scientific gap it addresses, e.g., limitations of prior single-source or coarse-resolution studies.

Multi-source datasets are mentioned, but the rationale for integrating radar, surface, lightning, video, and field data could be clarified; currently it reads as a list rather than showing how each contributes to understanding the mechanism.

Radar, surface, and lightning data are detailed, but the abstract does not clearly link them to downburst dynamics, microphysical processes, or resulting surface hazards.

A final statement about the broader implications or generalisability of the findings would strengthen the abstract for the journal audience, rather than focusing solely on the case study.

Introduction
The first paragraph is redundant and should be rephrased for clarity. Downbursts should be introduced as destructive convective phenomena with a summary of Fujita’s (1976) definition and classification (microburst vs. macroburst; wet vs. dry).

The aviation-specific definition at 100 m AGL is too detailed for the general introduction and could be shortened or moved later. If necessary, the significance and hazards should be explained clearly for aviation, maritime, and public safety, with representative incidents illustrating their destructive potential.

The classification of “microbursts (4m–4km) and microbursts (4–40km)” should be corrected to microbursts and macrobursts.

The research gap is not clear, i.e., current limitations in detection and analysis (radar, single-station data) should be highlighted.

Introducing the “May 4, 2025, accident” provides strong motivation, but the transition from background to research gap and case study is not smooth and should be clarified.

Examples such as the “Tragic Sinking of the Eastern Star” are important but are introduced abruptly and need smoother integration.

The final paragraph should condense the study aim into a single clear statement, e.g., investigating formation, evolution, and disaster-causing processes of the wet micro-downburst using multi-source data.

Phrases like “strong convective winds wet micro-downbursts through field observations” are grammatically incorrect and should be reworded for clarity. Also, typos such as “capsized of four passenger ships” should be corrected to “capsizing of four passenger ships.”

Numerical statements like radar echo intensity or precipitation thresholds should clarify whether they are general criteria or specific to this event.

Data description/ Weather conditions
Some sentences are long and dense. Example, line 77: “Data within 3 hours before and after the event were selected, with a focus on extracting 1-minute resolution of wind speed/direction, air temperature, pressure, and rainfall data from the ‘Tianqing’ Big Data Meteorological Cloud Platform…” could be split for clarity.

Were the measurements instantaneous or averaged values? Were gusts recorded differently from winds?

Figure references should be consistently numbered and integrated smoothly into the text.

Results
Combine Results and Discussion or move interpretations from Results to a separate Discussion.

4.1 Evolution characteristics of weather radar detection
Stay in Results:
Cite Figure 3 in the main text.

Radar echo evolution (dual-core -> crescent) and timing of downdraft (Figures 3 & 4).

REF, ZDR, VEL profiles, vertical descent of strong echo cores.

Move to Discussion / could be strengthened with additional content:
The link between dual-core to crescent-shaped echo evolution and downburst triggering could be emphasised more clearly.

Explicit quantification of the descent rate of strong echo cores to connect microphysical processes to surface wind observations.

Mechanistic explanation connecting ice-phase particle melting (high ZDR) and enhanced downdraft momentum could cite quantitative estimates of mass loading or evaporative cooling.

4.2 Evolution characteristics of wind, temperature, and air pressure at surface automatic stations
Stay in Results:
Cite figure 5 in the main text.

Surface wind speed and direction changes, temperature drops, precipitation accumulation, and air pressure changes (Figure 5).

Move to Discussion / could be strengthened with additional content:
Comparative assessment of spatial variation between R7676 and R7657 in terms of wind speed amplification by terrain.

Explicitly linking temperature drop magnitude and timing to downdraft momentum for quantitative correlation.

4.3 Lightning activity characteristics
Cite figure 6 in the main text.
4.4 Verification of disaster-causing process via video surveillance and on-site disaster traces
Stay in Results:
Cite figure 8 in the main text.

Temporal progression of downdraft in video surveillance, wind direction changes, hail, wave heights, and disaster damage observations (Figures 7 and 8).

Move to Discussion / could be strengthened with additional content:
Quantifying the correspondence between observed surface wind speeds and damage intensity in each zone.

Adding commentary on wind vector magnitudes or rotational components inferred from damage patterns.

Linking microphysical processes to surface impacts.

Discussion
This section is too short for Discussion. Either keep this only as a Conclusion paragraph or move the contents from the Results here.

Check grammar throughout the paper.

Reply
Citation: https://doi.org/10.5194/egusphere-2025-4293-RC1
- AC1: 'Reply on RC1', ankun wu, 23 Oct 2025 reply
  
  Thank you very much for your thorough review and valuable constructive comments on our preprint [EGUSPHERE-2025-4293]. We highly appreciate your insightful suggestions, which have provided important guidance for improving the quality and rigor of our manuscript.
  
  We have carefully read and fully acknowledged all the comments raised, covering structural optimization, content refinement, readability improvement, and grammatical standardization. Specifically, we note the key suggestions including: adjusting the structure of Results and Discussion to clarify the boundary between data presentation and interpretation; supplementing the scientific gap and multi-source data integration rationale in the abstract and introduction; optimizing the logical flow of the introduction and correcting definition/classification errors; splitting long sentences to enhance readability; and expanding the discussion section to highlight practical implications for hazard warning and mitigation.
  
  At present, we are systematically organizing the revision plan based on your comments. We will carefully deliberate on each suggestion during the manuscript revision process, conduct targeted adjustments (such as structural optimization, content supplementation, language polishing, and error correction), and ensure that the revised manuscript fully reflects your valuable insights while maintaining the scientific integrity of the research.
  
  We will submit the revised manuscript and a detailed point-by-point response as soon as possible. Once again, we sincerely thank the editors and reviewers for your time and professional guidance!
  
  Reply
  
  Citation: https://doi.org/10.5194/egusphere-2025-4293-AC1
RC2:
'Comment on egusphere-2025-4293', Anonymous Referee #2, 12 Nov 2025 reply

Overall Assessment: The manuscript presents a detailed multi-source data fusion analysis of a wet micro-downburst event that caused a passenger ship capsizing in Guizhou, China. The topic is important for improving the understanding of localized severe convective phenomena and their hazards. The study combines radar, surface, lightning, and video data — offering a rare and valuable integrated analysis.
However, the paper suffers from issues related to language clarity, structure, figure readability, and scientific interpretation depth. The physical mechanisms are well addressed but sometimes repetitive. Strengthening the discussion, scientific context, and comparative analysis with past cases would make the paper more impactful.

Abstract

1. The abstract is too detailed and technical, with numerical values that distract the reader from the main conclusions. It reads more like part of the “Results” section. I suggest rewriting the Abstract to emphasize the research question, data fusion novelty, and main findings, while keeping numbers minimal.

2. The abstract lacks a clear statement of novelty — what is new beyond earlier case studies such as the “Eastern Star” or previous Guizhou events. There should be a clear linkage between the event analysis and broader implications (e.g., warning systems, hazard prediction, or risk management).

3. Replace terms like “verifying the coupling disaster-causing mechanism of dynamic attenuation and microphysical transport” with simpler phrasing for better readability.

4. Improve grammar and sentence structure for flow.

Introduction

1. The introduction provides a good historical overview of downburst studies but lacks a clear research gap statement. Specify what is missing in current literature that this paper addresses (e.g., lack of integrated radar-lightning-video analysis for inland water disasters).

2. The link between ship disasters and meteorological mechanisms should be strengthened — currently it shifts abruptly between meteorology and maritime context.

3. Revise for smoother flow. The introduction has long paragraphs, mixes definition, examples, and motivation.

4. 4-40 km downbursts are also referred to as microbursts, please correct the typo error.

5. First two paragraphs of Introduction include repetitive explanation of downbursts, please revise to avoid repetition.

Results

Section 4.1: The radar analysis is comprehensive, but much of the text is descriptive rather than interpretative. It would strengthen the section to emphasize how radar features (REF, ZDR, VEL) jointly reveal the physical evolution of the micro-downburst.

Section 4.2: (i) Some statements, such as “typical extremely strong wind characteristics,” are qualitative. Consider including standard thresholds or reference criteria from prior downburst studies to support such claims.

(ii) The paragraph describing the lag between wind direction reversal and temperature change could be made more analytical — for instance, quantifying the time offset between dynamic and thermal responses.

Section 4.3: (i) The dominance of cloud flashes (85%) is noted but not physically explained. Please discuss why cloud-to-ground lightning is suppressed in cold pool environments and how that indicates microburst maturity.

(ii) Discuss the potential predictive role of lightning data — can such lightning characteristics be used in operational downburst detection or warning?

Section 4.4: (i) Clarify how the transition from northwesterly to southeasterly winds was inferred from visual cues — e.g., which camera angle or scene element was used as reference.

(ii) The timestamps from cameras (e.g., 08:18–08:40) should be explicitly cross-referenced with radar and surface observations to confirm temporal consistency.

Figures

1. Numerous figures are not referred to in the main manuscript. Please ensure that all figures are appropriately cited and discussed within the text to enhance clarity and coherence.

2. Please provide a detailed caption of Figure 3 which highlights the difference between 6 panels of the Figure.

Minor Comments:

Grammatical errors are found throughout the manuscript. Please carefully proofread the text for verb–tense consistency and sentence structure (e.g., “it has a complex formation mechanisms” → “it has complex formation mechanisms”).

Line 315: Correct spelling of “vedio” to “video.”

Define all observational variables and abbreviations upon first use (e.g., REF, ZDR, VEL, CG, RCS, etc.) and maintain consistency thereafter.

Line 200: Replace “however, .....” with “However, both....” for proper sentence initiation.

Line 40–45: Reorganize sentence for clarity; replace “which may, lead to loss of course control or even capsize” with “which may lead to loss of course control or even capsizing.”

Line 115–120: Replace “was lifed” with “was lifted.”

Ensure consistent formatting of references — use uniform punctuation, year placement, and DOI formatting (some have inconsistent spacing).

Reply

Citation: https://doi.org/10.5194/egusphere-2025-4293-RC2
- AC2: 'Reply on RC2', ankun wu, 16 Nov 2025 reply
  
  Thank you sincerely for your meticulous review and valuable insights on our preprint EGUSPHERE-2025-4293. We greatly appreciate your recognition of the study’s topic importance and the value of multi-source data fusion analysis, as well as your constructive suggestions targeting language clarity, structure optimization, scientific interpretation, and figure presentation. These comments are crucial for enhancing the manuscript’s quality and impact, and we have fully acknowledged each point.
  
  We note the key suggestions raised, including: refining the abstract to emphasize research questions, novelty, and broader implications while simplifying technical details; clarifying the research gap and strengthening the logical link between maritime disasters and meteorological mechanisms in the introduction; enhancing the analytical depth of the results section (e.g., quantifying key processes, explaining physical mechanisms of lightning characteristics); ensuring all figures are cited and their captions detailed; correcting typos, grammatical errors, and standardizing abbreviations and reference formatting.
  
  Reply
  
  Citation: https://doi.org/10.5194/egusphere-2025-4293-AC2

Ankun Wu, Xi Guo, Dan Yao, Xiaoling Du, Dongpo He, Jue Li, Shisheng Jin, and Tienan Bai

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Short summary

Wet microbursts threaten ships; mechanisms unclear from limited data. To address we studied 2025 Guizhou reservoir accident (four ships capsized) with radar weather stations lightning monitors videos damage surveys. Dense rainclouds descended suddenly near water triggering >34 m/s divergent winds capsizing ships. 14.9 °C temp drop sharp pressure rise intra-cloud lightning; on-site traces (directional tree lodging bidirectional building damage) confirmed divergent winds.


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Analysis on Multi-Factor Synergistic Hazards Mechanism of Wet Micro-downburst: Multi-Source Data Fusion Analysis based on Passenger Ship Capsizing Accident in Qianxi Region, Guizhou on May 4th, 2025

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Analysis on Multi-Factor Synergistic Hazards Mechanism of Wet Micro-downburst: Multi-Source Data Fusion Analysis based on Passenger Ship Capsizing Accident in Qianxi Region, Guizhou on May 4^th, 2025