A new dataset of Mesoscale Convective Complexes (MCC) derived from FY-2G satellite data

Xu, Ke; Zhao, Shuyun; Ma, Xinyu; Shu, Jianchuan; Wang, Wuke; Deng, Qimin; Babar, Zaheer Ahmad

doi:10.5194/essd-2025-652

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https://doi.org/10.5194/essd-2025-652

Preprints

19 Jan 2026

| 19 Jan 2026

Status: this preprint is currently under review for the journal ESSD.

A new dataset of Mesoscale Convective Complexes (MCC) derived from FY-2G satellite data

Ke Xu, Shuyun Zhao, Xinyu Ma, Jianchuan Shu, Wuke Wang, Qimin Deng, and Zaheer Ahmad Babar

Abstract. Mesoscale Convective Complexes (MCCs) are major convective weather systems occurring in midlatitude regions, typically associated with significant weather phenomena such as heavy rainfall, thunderstorms, strong winds, and hail. Based on the cloud-top temperature (CTT) data of the FY-2G satellite, and through multi-threshold screening combined with morphological analysis, an automated algorithm for MCC identification and tracking was developed. The algorithm is then applied to generate an hourly dataset of MCC variables over mainland China from June 2015 to December 2024. The dataset encompasses variables describing the spatial extent of the cold-core region (CTT < -52 °C) of MCCs, the minimum cloud-top temperature within the cold cloud shields, and the geographic coordinates (longitude and latitude) of the centroids of the cold cloud shields. This work also conducts a preliminary analysis of the spatial and temporal distribution characteristics of MCCs over mainland China based on the dataset. Results indicate that MCCs occur more frequently in Southwest China than in other regions of the country, and over 70 % of MCC events occur in summer both in Southwest China and mainland China. Moreover, MCC frequency in Southwest China exhibits significant interannual variability.

Received: 30 Oct 2025 – Discussion started: 19 Jan 2026

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Ke Xu, Shuyun Zhao, Xinyu Ma, Jianchuan Shu, Wuke Wang, Qimin Deng, and Zaheer Ahmad Babar

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RC1:
'Comment on essd-2025-652', Anonymous Referee #1, 07 Feb 2026 reply
Main comments:
This work developed an automated algorithm for mesoscale convective complex (MCC) identification and tracking, and then composed a long-term dataset of MCC variables over mainland China, based on the FY-2G cloud-top temperature data. MCC is an important type of convective system, often bringing about persistent heavy rain and secondary geologic disasters. Thus, this work has the potential in promoting the monitoring and research on the occurrence of MCC, and helping in disaster alleviation over the region. In general, the algorithm is described clearly, the manuscript is well-organized, and the dataset can be actually downloaded. However, there are some places (see specific comments) that need to be revised before it can be accepted for publication.
Specific comments:
At line 37, I think the authors mean “their variation” instead of “their formation”, as the Southern Oscillation, the Madden-Julian Oscillation are not short-term signals.

In lines 46-49, the sentence should be re-arranged to make its means more clear.

At line 80, the sentence begins with “Through multispectral sensing in the visible, infrared, and water-vapor bands, “ is not completed. It seems the latter part of the sentence is missed out.

In lines 80-83: “The satellite’s longitude has been relocated twice: initially at 99.5°E prior to June 1, 2015, ...” can be modified to be more concise. And I don’t understand whether the operational scan cycle is 30 or 60 minutes, or somewhere in the between.

Remove the “measurements” in line 85.

At line 89, what does the “nominal” mean?

At line 96, “reveal” -> “reveals”. And in line 104, “where” -> “with”

The sentence in lines 105-108 needs to be re-arranged. For example, what is the link between “ecc criterion is relaxed from ≥0.7 to ≥0.6 when the cold-cloud shield reaches its maximum extent” and “enabling capturing the full MCC lifecycle”?

At line 110, it is described that “all above morphological and area criteria are satisfied continuously for at least 6 hours”. However, in line 107, is seems that ecc ≥0.6 is only required when the cold-cloud shield reaches maximum extent. Can the authors re-check and clarify these two places?

The caption of Table 1, remove the “the”. And in the table, when a criterion is not used in either Maddox (1980) or this study, probably you can just use “~” instead of “null” or “Not specified”.

At line 124, “0.1°grid” -> “0.1°×0.1°grid”, and “optimizing” -> “to optimize”.

At line 150, “lenient parameter” -> “permissive threshold”, “formative stages” -> “early stages”

The caption of Figure 2 (line 162), I think area ≥ 4×10⁴km²is not applied in the subplot of b, or it will be repetitive with the subplot of c. By the way, Figure 2 has not been cited anywhere in the text.

At line 182, “the” -> “The”. And the citation of Fig. 4 should be put here instead of line 188.

The discussions in the two paragraphs of page 9 is a little puzzle for readers. For example, does the seasonally-filtered data mean winter-excluded data; and the unfiltered national data mean data of all seasons? Probably the authors can modify these two paragraphs to make them more clearly. And by the way, please don’t use “green and pink curves” or “black curve” to describe a scientific story.

The caption of Figure 5, “Area Probability Distribution Curve” -> “Probability distribution function of MCC areal extent. And the description of the three lines in the figure can be more concise.

At line 216, what does the “legitimate climatic signals” mean here. I think here is still about MCC, right? Climatic signals are too ambiguous.

At line 217, the “atmospheric divergence” is not precise here to express seasonal variation in weather pattern.

The caption of Figure 6, “cluster area” is not precise. Here each marker represents an MCC event, right? Then the marker size must represent the areal extent of the MCC event at some time point, mustn’t it?

At line 243, “demarcated in Fig. 6” can not been found in the Figure 6.

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Citation: https://doi.org/10.5194/essd-2025-652-RC1

Ke Xu, Shuyun Zhao, Xinyu Ma, Jianchuan Shu, Wuke Wang, Qimin Deng, and Zaheer Ahmad Babar

Data sets

A new dataset of MCC derived from FY-2G satellite data Ke Xu https://doi.org/10.5281/zenodo.17349888

Ke Xu, Shuyun Zhao, Xinyu Ma, Jianchuan Shu, Wuke Wang, Qimin Deng, and Zaheer Ahmad Babar

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Short summary

We developed an automated method using satellite data to create a decade-long record of major storm systems over China. Our results identify southwestern China as the country's primary storm hotspot and link year-to-year frequency changes to Pacific Ocean climate patterns. This new dataset is a vital resource for improving weather forecasts and climate research.


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