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• Investigate a novel TrFBWM to yield the TrF criteria weights. • Develop the TrFZSG to rank the alternatives. • Propose a TrF-BWM-ZSG by fusinging the BWM and ZSG. This paper investigates a hybrid emergency decision-making (EDM) method called TrF-BWM-ZSG by combining the BWM (best-worst method) and ZSG (zero-sum game) in trapezoidal fuzzy (TrF) environment. Firstly, this paper defines the entropy and similarity for trapezoidal fuzzy numbers (TrFNs). Based on the entropy and similarity measures, a bi-objective programming model is constructed to distribute the weights for experts. Then, based on the multiplicative consistent trapezoidal fuzzy reference comparisons (TrFRCs), a novel TrFBWM is investigated to yield the TrF criteria weights. This novel TrFBWM highlights two innovations: (i) A crisp goal programming weight-determining model is constructed by using the multiplicative consistent TrFRCs; (ii) A reasonable consistency ratio is defined, in which the consistency index is determined according to the consistent transitivity of TrFRCs. Afterwards, the TrFZSG is developed to achieve the alternatives' ranking order by extending the classical ZSG into TrF environment. Lastly, the availability of the TrF-BWM-ZSG is corroborated through a real EDM case of Henan rainstorm disaster. The advantages of the TrF-BWM-ZSG are manifested by several valuable comparisons. Some desirable results derived by the TrF-BWM-ZSG are received: (i) The optimal alternative selected by the proposed TrF-BWM-ZSG suits the actual rescue situation; (ii) The proposed TrF-BWM-ZSG owns high generality since TrFN can reduce to crisp number, interval and triangular fuzzy number; (iii) The developed novel TrFBWM is helpful to preserve more inherent information of TrFNs. [ABSTRACT FROM AUTHOR]

• The extent of flooding in China is greater than in any other country. • Nearly 66% of China's landmass is submerged by flooding. • Financial toll of flooding accounts for approximately 1.42% of the annual GDP. • Various forms of climatic change contribute to flooding. The extent of flooding in China is more significant than in any other country. Our research reveals that approximately 66 % of China's landmass is submerged by flooding, affecting about 50 % of the population. Furthermore, the financial toll of flooding now accounts for approximately 1.42 % of the annual gross domestic product (GDP), which is almost 40 times higher than the corresponding figure for the United States. We have observed that Zhengzhou city in Henan province, which faced a devastating flood in 2021, received a significant amount of rainfall, specifically a total of 552.5 mm within a 24-hour period. The floods in Henan province in 2021 caused considerable damage, including impacting nearly 15 million people, resulting in almost 400 deaths, damaging over 10,000 square kilometers of agricultural land, causing almost $19 billion in economic losses, and leading to the collapse of over 35,000 households and damage to various properties. In a similar manner, the significant flooding that occurred in southern China in 2020 impacted approximately 7.1 million individuals across eight provinces and resulted in 54 fatalities, the collapse of 6,700 houses, and incurred a direct economic loss of US$3.33 billion. We found that rainstorms have significantly increased to 10 % in the last 60 years in China. In this paper, we delved into exploring the existing published articles, reports, and government and authoritative legal texts to analyze the causes and impacts of flooding in China's flood-prone regions and potential mitigation strategies to reduce the repercussions of distressing flood events. We believe this study will help policymakers by providing new insights while formulating policy to reduce the loss caused by high-level flooding. [ABSTRACT FROM AUTHOR]

By using the observation data of four DSG5-type disdrometers, four automatic weather stations and two dual-polarization Doppler weather radars, this paper analyzes the characteristics of raindrop size distributions (DSDs) and their integral parameters during the severe precipitation in Henan Province, China, specially focusing on the extremely severe rainstorm on the 20 July 2021 in Zhengzhou City. The results show that: (1) In line with most of the severe precipitation in northern China, the July 2021 extreme precipitation were dominated by small raindrops, but medium-sized raindrops with diameter D in 2–4 mm contributed 61.28% to the rain rate R during the time period of extremely severe rainfall at Zhengzhou (ZZ) station, and the raindrops with D > 4 mm contributed 53.74% to the radar reflectivity factor Z. (2) Quantitative evaluation of the gamma model of DSD for different values of R is carried out, and the fitting effect of the gamma model is better for the raindrop spectrum with a single peak structure. However, this method cannot reflect the double-peak structure when R is large. (3) Some differences have been found in the Z - R relationship between Z and R among the four stations (GY, XM, XY, and ZZ). The maximum value of fitting coefficient a appears at the ZZ station, which is close to the a values in the Meiyu season in eastern China. For the other three stations, the a values are comparable to those of typhoons in the western Pacific, but the fitting coefficient b values are less different. (4) The average vertical profiles of dual-polarization radar parameters reveal the microphysical characteristics of the extremely severe rainstorm, that is, there were active ice-phase and warm-rain microphysical processes in the convective system of the extremely severe rainfall, of which the warm-rain process was more dominant. • The DSDs and microphysical characteristics at four weather stations of Zhengzhou City during the 20 July 2021 extremely heavy rainfall period were discussed. • There were three stations with diameter-controlled raindrop size distribution characteristic, only one station was controlled by both number concentration and diameter, the scatter pairs of parameters lg N w - D m of DSDs recorded of ZZ station indicate maritime-like convection. • Quantitative evaluation of the gamma model of DSDs for different rain rate was conducted. The fitting effect of the gamma model is better for the DSD with a single peak structure, while the method cannot reflect the double-peak structure when rain rate is large during the heavy rainfall period. • During the extreme rainfall period, there are active ice-phase and warm-rain microphysical processes in the convection system, and the warm-rain process is dominant. [ABSTRACT FROM AUTHOR]