Impact Area Research Articles

Spatial patterns of macrozoobenthos diversity on sewage-impacted intertidal rocky shores in Central Patagonia, Argentina

The effects of untreated wastewater and shore levels on zoobenthic diversity, species accumulation, and abundance-biomass relationships were studied on intertidal rocky shores of central Patagonia, Argentina. Winter samples (2015) from two sewage-impacted and two reference sites showed that pollution disrupted macrozoobenthic diversity and zonation. A total of 83 taxa were identified, with polychaetes (31 species), mollusks (22), and crustaceans (21) being the most diverse. Impacted sites had greater intra-environmental diversity heterogeneity and higher abundance at the lower midlittoral level, indicating a shift towards lower intertidal levels. Species richness was lower and evenness was higher in the polluted mid-littoral level. ABC curves in the stressed areas showed moderate disturbances with variability across shore zones, while non-polluted rocky shores typically exhibit a higher cumulative faunal biomass than abundance. In impacted areas, chronic habitat changes and disturbances to the mussel matrix by Perumytilus purpuratus are likely responsible for differences in diversity and abundance-biomass relationships.

Scientometric Insights into Rechargeable Solid-State Battery Developments

Solid-state batteries (SSBs) offer significant improvements in safety, energy density, and cycle life over conventional lithium-ion batteries, with promising applications in electric vehicles and grid storage due to their non-flammable electrolytes and high-capacity lithium metal anodes. However, challenges such as interfacial resistance, low ionic conductivity, and manufacturing scalability hinder their commercial viability. This study conducts a comprehensive scientometric analysis, examining 131 peer-reviewed SSB research articles from IEEE Xplore and Web of Science databases to identify key thematic areas and bibliometric patterns driving SSB advancements. Through a detailed analysis of thematic keywords and publication trends, this study uniquely identifies innovations in high-ionic-conductivity solid electrolytes and advanced cathode materials, providing actionable insights into the persistent challenges of interfacial engineering and scalable production, which are critical to SSB commercialization. The findings offer a roadmap for targeted research and strategic investments by researchers and industry stakeholders, addressing gaps in long-term stability, scalable production, and high-performance interface optimization that are currently hindering widespread SSB adoption. The study reveals key advances in electrolyte interface stability and ion transport mechanisms, identifying how solid-state electrolyte modifications and cathode coating methods improve charge cycling and reduce dendrite formation, particularly for high-energy-density applications. By mapping publication growth and clustering research themes, this study highlights high-impact areas such as cycling stability and ionic conductivity. The insights from this analysis guide researchers toward impactful areas, such as electrolyte optimization and scalable production, and provide industry leaders with strategies for accelerating SSB commercialization to extend electric vehicle range, enhance grid storage, and improve overall energy efficiency.

Quantitative risk assessment of road exposed to landslide: A novel framework combining numerical modeling and complex network theory

The quantitative analysis of the landslide risk posed to road networks is a challenging task owing to the uncertainty involved both in the potential landslide hazard and the road value. To address this challenge, this paper proposes a novel framework to assess the road risk in quantitative terms. The landslide hazard is assessed using the depth-integrated method with consideration of the landslide size probability and initial conditions. The potential direct losses associated with road disruption are determined by exposure analysis in a geographical information system. The indirect losses of the road caused by the landslide were analyzed through complex network theory with consideration to regional socioeconomic development and the time required for road restoration. The proposed framework was used to assess the road risk posed by the Chunchangba landslide, Xiaojin County, China. The results show that the volume size probability of landslides in the Xiaojin area could be assessed using the function PVL=1/1+3.583×10−5VL2×0.391. The depth-integrated method based hazards assessment results show the maximum impact area of the Chunchangba landslide reached 0.383 km2, and the landslide has a high probability of damaging the lower road and forming a barrier lake. The losses associated with road disruption caused by the landslide were estimated. The maximum direct losses reached 293,100 USD, while indirect losses reached 423,800 USD, which has the same importance as direct losses. The risk curve reveals that the maximum probability of the road risk associated with the Chunchangba landslide is 0.0175 %, 0.0189 %, 0.0190 %, and 0.0191 % for the time interval of 5, 10, 20, and 50 years, respectively, with losses of 0.177 million USD/year. The regional disaster mitigation strategy is analyzed based on quantitative risk analysis. The results show that a new 2.7 km road on the mountain opposite the Chunchangba landslide can reduce indirect losses by approximately 300 times. The findings of this study contribute to sustainable development and landslide risk management in mountainous areas.

Update from 2010 (standard operating procedure): protocol for the 2024 British Society of Gastroenterology Guidelines on colorectal surveillance in inflammatory bowel disease

IntroductionThe evolving landscape of inflammatory bowel disease (IBD) necessitates refining colonoscopic surveillance guidelines. This study outlines methodology adopted by the British Society of Gastroenterology (BSG) Guideline Development Group (GDG) for...

Extent of Benthic Habitat Disturbance by Offshore Infrastructure

The effects of the interaction between sandy, mobile, low-relief (sorted) bedforms and two sewage outfalls were investigated along the south shore of Long Island, NY. Sand bedforms at scales from ripples to ridges are common on continental shelves. In dynamic environments, these features can migrate 10s to 100s of meters per year, especially during storms. Beyond engineering considerations, little is known of the interaction between these mobile features and anthropogenic structures. Modification of bedform topography and sediment grain-size distribution can be expected to alter the species composition, abundance, and diversity of the benthic community. At the study site, the interaction increased the scour of modern fine- to medium-grained sediments extending out to a kilometer and uncovered coarser-grained late Pleistocene sediments. This alteration of the seafloor in turn resulted in changes in composition, higher abundance, and lower diversity in the species assemblage found in the impacted area. The most advantaged species was Pseudunciola obliquua, a sightless, tube-building, surface deposit-feeding amphipod that is known to prefer a dynamic coarse sand habitat. Overall, the ecological effects of artificial structures on a wave-dominated seabed with sorted bedforms have not been adequately assessed. In particular, and of great importance, is the pending large-scale development of wind farms off the East Coast of the U.S.

Development and Application of Small Object Visual Recognition Algorithm in Assisting Safety Management of Tower Cranes

This study presents a novel video-based risk assessment and safety management technique aimed at mitigating the risk of falling objects during tower crane lifting operations. The conventional YOLOv5 algorithm is prone to issues of missed and false detections, particularly when identifying small objects. To address these limitations, the algorithm is enhanced by incorporating an additional small object detection layer, implementing an attention mechanism, and modifying the loss function. The enhanced YOLOv5s model achieved precision and recall rates of 96.00%, with average precision (AP) values of 96.42% at an IoU of 0.5 and 62.02% across the range of IoU values from 0.5 to 0.95. These improvements significantly enhance the model’s capability to accurately detect crane hooks and personnel. Upon identifying the hook within a video frame, its actual height is calculated using an interpolation function derived from the hook’s dimensions. This calculation allows for the precise demarcation of the danger zone by determining the potential impact area of falling objects. The worker’s risk level is assessed using a refined method based on the statistical analysis of past accidents. If the risk level surpasses a predetermined safety threshold, the worker’s detection box is emphasized and flagged as a caution on the monitoring display.

Impact of pressure injuries on health-related quality of life: A systematic review.

The objective of this systematic review was to synthesise the evidence of the impact of pressure injuries (PIs) on the health-related quality of life (HRQoL) of adults aged 18 years and older. Electronic databases (Ovid Medline, Ovid Embase, CINAHL EBSCO, Scopus and Central Register of Controlled Trials) were searched for eligible studies published between January 2019 and April 2024. All identified articles were reviewed by two reviewers against the eligibility criteria. The risk of bias was assessed using the Mixed Methods Appraisal Tool and the Joanna Briggs Institute critical appraisal tool. Data were narratively synthesised due to methodological heterogeneity. Twenty-two studies (12 quantitative; 9 qualitative;1 mixed methods) met the inclusion criteria. The qualitative studies were grouped into four impact areas: symptoms, physical function, psychological well-being and social functioning. Five instruments were used to assess HRQoL and identified low scores in people with PIs, with the lowest scores mostly reported in physical functioning and role physical and emotional concepts. A complexity of factors influenced theHRQoL of people with PI. This review synthesised both quantitative and qualitative evidence indicating PI was associated with low HRQoL scores and negatively affected all aspects of HRQoL. This review emphasised the complexity of factors related to PI and its impact on HRQoL. Further emphasis on the impact of the complexity of factors on HRQoL of people with PI should be considered in future studies.

Earthquake risks assessment and urban vulnerability: Case of Nador city, northeast Morocco

This study introduces an innovative approach to assessing seismic risks and urban vulnerabilities in Nador, a coastal city in northeastern Morocco at the convergence of the African and Eurasian tectonic plates. By integrating advanced spatial datasets, including Landsat 8–9 OLI imagery, Digital Elevation Models (DEM), and seismic intensity metrics, the research develops a robust urban vulnerability index model. This model incorporates urban land cover dynamics, topography, and seismic activity to identify high-risk zones. The application of Landsat 8–9 OLI data enables precise monitoring of urban expansion and environmental changes, while DEM analysis reveals critical topographical factors, such as slope instability, contributing to landslide susceptibility. Seismic intensity metrics further enhance the model by quantifying earthquake risk based on historical event frequency and magnitude. The calculation based on higher density in urban areas, allowing for a more accurate representation of seismic vulnerability in densely populated areas. The modeling of seismic intensity reveals that the most susceptible impact area is located in the southern part of Nador, where approximately 50% of the urban surface covering 1780.5 hectares is at significant risk of earthquake disaster due to vulnerable geological formations, such as unconsolidated sediments. While the findings provide valuable insights into urban vulnerabilities, some uncertainties remain, particularly due to the reliance on historical seismic data and the resolution of spatial datasets, which may limit the precision of risk estimations in less densely populated areas. Additionally, future urban expansion and environmental changes could alter vulnerability patterns, underscoring the need for continuous monitoring and model refinement. Nonetheless, this research offers actionable recommendations for local policymakers to enhance urban planning, enforce earthquake-resistant building codes, and establish early warning systems. The methodology also contributes to the global discourse on urban resilience in seismically active regions, offering a transferable framework for assessing vulnerability in other coastal cities with similar tectonic risks.

Settlement Pattern Features in Mountainous Countries (on the Example of the Republic of Armenia)

Despite the current variety in settlement patterns, mountainous countries share certain similarities in features, characteristics, trends, and issues related to settlement patterns. This article discusses the geographical peculiarities of settlement patterns in mountainous countries using the Republic of Armenia (RA) as an example. It then differentiates the types of settlement pattern territorial units in the RA, considering several principles of geographical organization, such as altitudinal zonation, the impact areas of settlement system centers, and border positions. The analysis of settlement pattern features in mountainous countries, along with the identification of characteristics and typological zoning of settlement patterns, provides a necessary scientific basis for developing and implementing regional policies to regulate settlement patterns.

Subsurface Weave Pattern Influences on Polymer Cold Spray Deposits onto Woven Fiber-Reinforced Composites

AbstractThe polymer cold spray (CS) process has recently been demonstrated as a promising coating and repair technique for fiber-reinforced polymer composites (FRPs). However, a noticeable variation in coating thickness (herein referred to as checkerboard pattern) often occurs in the initial pass of low-pressure CS deposition. The checkerboard pattern occurs due to the periodic variations in matrix thickness and volume above the subsurface fiber weave pattern. When the initial pass exhibits the so-called checkerboard pattern, the CS deposition for subsequent passes may be negatively affected in terms of deposition efficiency, porosity, adhesion, surface roughness, and thickness consistency. The present work compares results of both numerical simulations and experimental studies performed to reveal the governing mechanisms for and elimination of checkerboarding. Single particle impact numerical simulations are conducted to observe thermomechanical behavior of particles during CS impact on the FRP surface at different regions of the composite material. Complementary experimental CS studies of exemplar powders onto FRPs with various surface interlayer thicknesses are also presented and discussed. Experimental analyses of deposits include microstructural observations to compare against the simulations while also providing practical strategies for the elimination of checkerboarding effects. It is demonstrated that the thickness and volume of the matrix region underneath the impact area are the main contributing factors that govern the CS deposition variations on CFRP substrates. As such, increasing the surface epoxy layer thickness beyond a critical value can reduce the effect of substrate stiffness effects imposed by the subsurface fiber tows, thereby effectively eliminating the checkerboard patterns.

A Novel Method for Evaluating Earthquake Forecast Model Performance and Its Implications for Refining Seismic Likelihood Model

Summary Utilizing statistical tests to evaluate earthquake forecasting models is crucial to improve forecasting strategies for seismic hazard assessment. We develop a novel evaluation method for alarm-based earthquake forecast, taking into account the magnitude of seismic energy and the impact area of earthquakes, instead of using solely seismic event number and epicenter locations in conventional approaches. First, we derive a scale-law of Seismic Area by statistically analyzing coseismal maps of past M ≥ 7.0 earthquakes. Second, we proportionally allocate Seismic Moment to surrounding cells based on corresponding seismic area within each cell (SASM-test). Compared to the Molchan test which is conventionally applied for models that forecast the epicenter location, our proposed SASM-test can be applied to the evaluation of forecasting models that focus on the whole earthquake rupture (source area). Third, we apply the SASM-test method to the time-independent probabilistic earthquake forecasting model for the southeastern Tibetan Plateau (RELM-TibetSE) and compare it with other evaluation methods. The retrospective testing shows that the SASM-test demonstrate relatively higher sensitivity, enabling to detect subtle differences between similar models that conventional methods may overlook. Additionally, retrospective test results indicate that: (a) Earthquake forecasting models using GNSS data performed better in forecasting the ‘source area’ than the ‘epicenter location’; (b) Forecasting models based on principal strain rate outperformed the models based on maximum shear strain rate in forecasting both the epicenter location and the source area; (c) Incorporating spatially varying seismogenic layer thickness and rigidity into seismic forecasting models could improve their ability to forecast the ‘source area’ compared to using uniform seismogenic layer properties. The newly proposed SASM-test method can provide a more sensitive and comprehensive approach for the evaluation of earthquake forecasting models, contributing to the refinement of seismic hazard assessments.

The security implications of using feminist methodologies to study gender-based violence in Yemen.

This paper examines the political and security implications of gender-based violence (GBV) research in Yemen during the period (2019-2023). As various radical groups are gaining power over Yemeni land, radical views toward women and gender equity and equality shape the experiences of GBV survivors, practitioners, and researchers in the North of Yemen. Policing Houthi ideologies in Yemen have curtailed GBV research and subjected feminist research to myriad risks. If this situation continues, experiences of women and girls in Yemen will not be captured by research. Their stories and needs will not be captured by humanitarian and peace-building actors. Findings of this study are based on primary data from key informant interviews with 25 GBV researchers actively engaged in Yemen. Sampling followed the snowballing technique. The findings examine political and security power dynamics after the Houthi radical group took control in the north of Yemen, and implications on GBV research design. Anti-feminist ideologies coupled with extreme security measures have impacted quality of GBV study methodologies as well as researchers' safety and mobility. Donors of previously established GBV programs and research were harassed to change research topics or lose permission to speak to local communities or collect data from aid beneficiaries. Researchers who do not follow new rules of engagement with the community are detained, harassed and their devices and databases are confiscated. Terms like "gender" and "GBV" are not deemed acceptable as these are western concepts that do not align with new community values. The findings highlight the need to use conflict-sensitivity and Do No Harm principles in settings where GBV work is scrutinized. It also challenges the orthodox definition of "GBV evidence" and explores the ethical implications of the use of alternative means to collecting data. Findings also provide insight into valuable alternative methodologies that allow local and national researchers to continue studying GBV in conflict impacted areas without exposing themselves to actual or perceived risk. The paper proposes concrete approaches that can mitigate political and security risk on both researchers and GBV survivors.

Effects on personal and cultural wellbeing of attending free community outreach concerts given by a professional orchestra

Despite hundreds of investigations into the benefits of arts engagement for health and wellbeing, much of what we know comes from research in clinical settings, and little is understood about the positive effects of attending live musical performances. As many professional orchestras have begun re-examining their purpose and mission statements, they also seek ways to measure their impact beyond ticket sales and donations in hopes of highlighting positive effects on concertgoers and their community. The purpose of this study was to explore the impacts of a free community outreach concert series provided by a professional orchestra on individual and community wellbeing in a large city in the United States. The researchers conducted semi-structured interviews, paired interviews, and a focus group with 18 participants between the ages of 18 and 77 years. Abductive analysis allowed us to consider emerging themes and pre-existing theories of wellbeing concurrently. The results showed three primary areas of impact on concert attendees’ wellbeing: emotional, social, and cultural. Concert attendance fostered positive emotional states and reduced negative emotions, led to personal feelings of connection with the orchestra and across the community, and contributed to personal- and local-cultural wellbeing. In addition to reinforcing much of the prior scholarship on the effects on wellbeing of arts participation, particularly in the emotional and social domains, the results highlight new possible connections between community outreach programs and increased cultural wellbeing.

Physically based probabilistic prediction of regional rainfall-induced shallow landslides: from initiation to runout analysis

ABSTRACT In this study, a physically based method is proposed to estimate the exceedance probability of the intensity measure of the regional rainfall-induced shallow landslides. This method consists of a digital elevation model, an initiation model, a runout model and a probabilistic analysis model. In the suggested method, a study area is discretised into a grid of cells, and the stability of each cell can be evaluated through the initiation model. Then, the runout behaviour of the unstable cells can be simulated by the runout model. Finally, the exceedance probability of the intensity measures of each cell can be estimated through Monte Carlo simulation considering the uncertainties in the initiation model and runout model. The proposed method is applied to analyse the rainfall-induced landslides in a study area in the southwest of China, which can provide a reasonably accurate prediction of the impact zones of the landslides. The suggested method provides a useful tool to probabilistically predict the impacted area of the rainfall-induced landslides at a regional scale.

Improvement of Coal Mining-Induced Subsidence-Affected (MISA) Zone Irregular Boundary Delineation by MT-InSAR Techniques, UAV Photogrammetry, and Field Investigation

Coal mining-induced ground subsidence is a severe hazard that can damage property, infrastructure, and the environment in the vicinity when the deformation is not negligible. The boundary of a mining-induced subsidence-affected zone refers to the area beyond which the ground subsidence is less concerned. Accurately measuring mining-induced ground deformation is essential for delineating the irregular boundary of the impacted area. This study employs multitemporal interferometric synthetic aperture radar (MT-InSAR) techniques, including differential InSAR (DInSAR), InSAR stacking, and interferometric point target analysis (IPTA), to analyze coal mine subsidence and delineate the boundaries of the mining-impacted zones. DInSAR accurately reconstructs, locates, and detects the trend in mining-induced subsidence and correlates well with documented mining operations. The InSAR stacking method maps the spatial variation of the ground’s average line-of-sight (LOS) velocity over the mining area, delineating the boundary of the impacted zone. IPTA analysis combining multilook and single-pixel phases achieves millimeter-level surface measurement above tunnel alignments and measures unevenly distributed deformation fields. This study considers an average of 4 cm per year of surface deformation in the LOS direction as the subsidence threshold value for delineating the boundary of the mining-induced subsidence-affected (MISA) zone during the active coal mining stage. Interestingly, there are twin transportation tunnels near the mining area. The twin tunnels completed before the coal mining activities started were functioning well, but damage was observed after the mining began. Our study reveals the tunnels are located within the InSAR-derived MISA zone, although the tunnels approach the MISA boundary. As direct signs of subsidence, ground fissures have been identified near the tunnels via field investigations and UAV photogrammetry. Furthermore, the derived distribution of ground fissures validates and verifies InSAR measurements. The integrated approach of MT-InSAR, UVA photogrammetry, and field investigation developed in this study can be applied to delineate the irregular boundary of the MISA zone and study the accumulating effects of mining-induced subsidence on the performance of infrastructure in areas proximate to coal mining activities.

Investigation of thunderstorm characteristics with severe lightning events over NE region of India

Abstract. The north eastern region (NER) of India is among the hotspot regions for thunderstorm events leading to substantial loss of lives and properties every year. A reliable thunderstorm early warning system can prevent these losses. As these events are highly dynamic, prediction becomes equally challenging. Diagnostic studies of such events could provide more understanding of lightning and storms over a region which could then be used as input for the prediction of such events. Improving the efficiency of the prediction of associated meteorological parameters could improve the prediction of thunderstorm. In this study, two thunderstorm events have been identified with high lightning flash counts, using observations from the INSAT-3D satellite and lightning detection sensors. These observations revealed that one of the events was caused by a cloud system that originated elsewhere and travelled over the area of impact while the other event was an isolated convective system that occurred over a small region. The characteristic features of thunderstorms, like vertical wind velocity, cloud ice water content, relative humidity, cloud fraction and radar reflectivity, etc. were simulated using the WRF model. These simulations were validated with the ERA-5 reanalysis data and observations from Radar and satellite data. Validation results suggest that the WRF model could predict these features associated with thunderstorm events quite reliably. The study helped to improve the severe weather warning over NER of India and the stakeholders are trained on effective utilization of such warning.

Evaluating the effects of drafting formations on athletes' heat dynamics and performance via coupled CFD and thermoregulation model

Research indicates that drafting enhance performance across various sports. Current studies concentrate on drafting impact on reducing drag, with limited research on thermoregulation and sweating. This article explores how drafting formations affect the athlete's microenvironment using CFD and thermoregulation model. This study investigates how drafting influences heat production, dissipation, and sweating while maintaining consistent core and skin temperature, considering the impact of drag reduction on mechanical work. The average hc during race walking alone is the highest at 37.34, followed by double formations 1, 2, and 3, which are 36.34, 36, and 34.74 respectively. This represents a decrease of 2.7 %, 3.6 %, and 7 %. These reductions can be attributed to the lower Reynolds number and turbulent diffusion coefficient observed in the mainstream. Compared to race walking alone, in double formations with varying distances, core athlete experienced increased sweating heat dissipation by 0.23 %, 0.24 %, 0.28 %, and skin blood flow by 0.31 %, 0.39 %, 0.65 %. Additionally, the pelvis is identified as the most impacted area. However, reduced drag leads to less metabolic heat production, resulting in decreased sweating and skin blood flow. Compared to race walking alone, the sweating heat dissipation is reduced by 3.44 %, 4.71 %, and 6.72 % in double formations at varying distances, while skin blood flow is reduced by 3.16 %, 4.38 %, and 6.39 %. These changes positively impact performance. Additionally, the drag reduction rate is inversely correlated with the percentage difference in skin blood flow and sweating heat dissipation, with negative correlation coefficients of 0.116 and 0.119, respectively. Therefore, this article emphasizes how drafting reduces sweating and skin blood flow, highlights the importance of thermoregulation, and offers valuable guidance for training and hydration strategy.

The Impact of Cruise Product Consumption Phases on Cruise Passenger Spending in a Non-Overnight Stay Port: Implications for Destination Managers

The level of expenditure by cruise passengers in the various cities visited during their journey is a crucial variable for the key stakeholders involved in this industry. Promoting higher spending by cruise passengers in non-overnight stay ports is a challenge led by the destination manager. This study aims to shed light on the effect that different phases in the cruise passenger’s travel cycle have on their propensity to spend during their stay. Our case focuses on the city of A Coruña, a non-overnight stay port on Europe’s Atlantic arc routes, where the average spending per cruise passenger during their visit is quite low. The analysis considers the impact of passenger profiles and the cruise product consumption phases on the average spending per passenger. From a methodological perspective, we have applied logistic regression. The results indicate that the profile of the cruise passenger, variables related to the onboard journey, and the experience of the city are the factors with the greatest potential to increase cruise passenger spending during their visit to the city. This has allowed the areas of greatest impact and where actions should be focused to be identified for both the destination manager and key stakeholders.

Damage Characterization of GFRP Hollow Ribbed Emergency Pipes Subjected to Low-Velocity Impact by Experimental and Numerical Analysis.

This paper investigates the low-velocity impact response and damage behavior of glass fiber reinforced polymer (GFRP) hollow ribbed emergency pipes of our design under different impact heights. Drop hammer impact tests with impact velocities of 8.41 m/s, 8.97 m/s, and 9.50 m/s were conducted using an impact platform. A progressive damage model for low-velocity impact was developed using Abaqus/Explicit finite element software. The model used the three-dimensional Hashin damage initiation criteria and a damage evolution model based on the equivalent strain method to simulate the initiation and evolution of intralaminar damage in the pipe ring. A cohesive zone model (CZM) based on a bilinear traction-separation law was used to simulate delamination. The results show that the pipe rings experienced fiber or matrix fractures and delamination damage during the impact process. Additionally, the pipe ring specimens underwent bending vibrations under the impact load, leading to fluctuating contact forces at all three impact heights. Analysis of the simulation results reveals that the primary damage modes in the GFRP hollow ribbed emergency pipe are fiber tension damage, matrix tension damage, and fiber compression damage, with delamination occurring mainly in the impact area and the interface area on both sides of the rib.

China is suffering from fewer but more severe drought to flood abrupt alternation events

Drought to flood abrupt alternation (DFAA) events, as a special category of compound extreme events that suddenly shift from drought to flood conditions, have significantly greater impacts than individual drought or flood events. In this paper, we have utilized a multifactorial drought index and flood index to identify daily DFAA events occurring in mainland China and in major impact areas during the period 1961–2022. Based on drought and flood index, we have used entropy weighting method to measure the intensity of DFAA events. Our findings indicate that China's DFAA events primarily occur in the hotspots of Huang-Huai-Hai River Basin, the middle and lower Yangtze River Basin, the southeastern coastal area, and the southwestern part of the country. The most frequent and intense DFAA events occur from June to September, with varying subseasonal patterns in the frequency and intensity of events in each hotspot. The frequency of DFAA events in mainland China shows a significant decreasing trend declining at a rate of 0.25 per year in year-round. While DFAA events occurring in the warm season tend to decrease more significantly compared to the year-round at a rate of 0.26 per year. However, the intensity of DFAA events is increasing with a rate of 0.1 per decade in both the year-round and warm season. The evolution of DFAA events and their direct causes varies non-uniformly across regions and months. Subseasonally, frequency and intensity trends diverged monthly across regions, notably with the Huang-Huai-Hai Basin and southeast coast experiencing a July decline in frequency but a surge in intensity. Our research deepens the understanding of changes in DFAA events and provides practical reference for preventing and mitigating drought-to-flood disasters in mainland China.