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How Many Floods Have Occurred in China in the Past Decade? A Perspective From Social Media.

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Title: How Many Floods Have Occurred in China in the Past Decade? A Perspective From Social Media.
Authors: Shen, D., Gu, H., Chen, W., Zhang, C., Xiao, S., Zhang, S.
Source: Earth's Future; Apr2025, Vol. 13 Issue 4, p1-27, 27p
Subject Terms: SOCIAL media, DETECTION algorithms, CLIMATE change, CITIES & towns, RESEARCH personnel
Abstract: Global climate change has led to frequent and widespread flood disasters in China. Traditional flood disaster investigations mainly focus on major flood events, and small‐scale flood events are often overlooked. This study utilized the Sina Weibo social media platform to detect flood events in 370 cities in China from 2012 to 2023. We downloaded 73.52 million Weibo posts and developed a two‐step flood detection algorithm. In the first step, the algorithm initially identifies 956 flood events based on changes in posting frequency. In the second step, an LDA topic model is used to detect topics for these flood events and automatically filter out false events, resulting in 729 flood events. Verification of these events confirmed that 629 of the 729 were real flood events, achieving a detection accuracy of 86.28%. In the end, after excluding all false flood events and reinstating the mistakenly removed real ones, we obtained a total of 674 verified flood events. Among these 370 cities, 194 cities experienced flood disasters, accounting for 52.43% of the total. Additionally, we compared our findings with online news reports, as well as the flood data sets from the GDACS and EM‐DAT. We found that our study had a high detection rate for urban waterlogging events. However, there were cases of missed detection for flash floods and small watershed flood disasters. Nevertheless, this study represents the most comprehensive publicly available detection of flood events in China to date, which is of great significance for the government's flood management and decision‐making. Plain Language Summary: Climate change has led to a significant increase in extreme precipitation events in China, resulting in a rise in flood disasters across the country. However, our understanding of the frequency and distribution of flood events in China remains limited due to the lack of an effective monitoring and reporting mechanism. To address this gap, researchers from Central China Normal University analyzed data from the Sina Weibo to detect flood events in 370 cities in China between 2012 and 2023. They identified a total of 674 flood events from 73.52 million Weibo posts, indicating that over half of Chinese cities (52.43%) have experienced flood events in the past decade. The majority of these cities are located in the eastern and central regions of China, with 12 cities reporting 10 or more flood events. Specifically, Xi'an, Chengdu, Tianjin, and Chongqing have been the hardest hit, with the highest number of flood events. The northwest region of China, which has lower precipitation and population density, has seen fewer flood events. This study provides valuable insights into the current flood situation in Chinese cities, highlighting the need for effective monitoring and reporting mechanisms to mitigate the impact of climate change on flood disasters. Key Points: This study utilized the Sina Weibo platform to detect flood events in 370 cities in China from 2012 to 202352.43% of cities have experienced flood events, among which Xi'an, Chengdu, Tianjin, and Chongqing have had the most occurrencesThe detected and validated 674 flood events are mainly distributed in eastern and central China [ABSTRACT FROM AUTHOR]
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Database: Complementary Index
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Abstract:Global climate change has led to frequent and widespread flood disasters in China. Traditional flood disaster investigations mainly focus on major flood events, and small‐scale flood events are often overlooked. This study utilized the Sina Weibo social media platform to detect flood events in 370 cities in China from 2012 to 2023. We downloaded 73.52 million Weibo posts and developed a two‐step flood detection algorithm. In the first step, the algorithm initially identifies 956 flood events based on changes in posting frequency. In the second step, an LDA topic model is used to detect topics for these flood events and automatically filter out false events, resulting in 729 flood events. Verification of these events confirmed that 629 of the 729 were real flood events, achieving a detection accuracy of 86.28%. In the end, after excluding all false flood events and reinstating the mistakenly removed real ones, we obtained a total of 674 verified flood events. Among these 370 cities, 194 cities experienced flood disasters, accounting for 52.43% of the total. Additionally, we compared our findings with online news reports, as well as the flood data sets from the GDACS and EM‐DAT. We found that our study had a high detection rate for urban waterlogging events. However, there were cases of missed detection for flash floods and small watershed flood disasters. Nevertheless, this study represents the most comprehensive publicly available detection of flood events in China to date, which is of great significance for the government's flood management and decision‐making. Plain Language Summary: Climate change has led to a significant increase in extreme precipitation events in China, resulting in a rise in flood disasters across the country. However, our understanding of the frequency and distribution of flood events in China remains limited due to the lack of an effective monitoring and reporting mechanism. To address this gap, researchers from Central China Normal University analyzed data from the Sina Weibo to detect flood events in 370 cities in China between 2012 and 2023. They identified a total of 674 flood events from 73.52 million Weibo posts, indicating that over half of Chinese cities (52.43%) have experienced flood events in the past decade. The majority of these cities are located in the eastern and central regions of China, with 12 cities reporting 10 or more flood events. Specifically, Xi'an, Chengdu, Tianjin, and Chongqing have been the hardest hit, with the highest number of flood events. The northwest region of China, which has lower precipitation and population density, has seen fewer flood events. This study provides valuable insights into the current flood situation in Chinese cities, highlighting the need for effective monitoring and reporting mechanisms to mitigate the impact of climate change on flood disasters. Key Points: This study utilized the Sina Weibo platform to detect flood events in 370 cities in China from 2012 to 202352.43% of cities have experienced flood events, among which Xi'an, Chengdu, Tianjin, and Chongqing have had the most occurrencesThe detected and validated 674 flood events are mainly distributed in eastern and central China [ABSTRACT FROM AUTHOR]
ISSN:23284277
DOI:10.1029/2024EF004775