International Journal of Climatology最新文献

{"title":"Aerosol–Climate Interaction in the South Asian Region: A Focused Exploration of the Impacts of Ozone, Black Carbon, Optical Properties and Radiative Forcing in a Region of Significant Climate Change Dynamics","authors":"Kazi Rakib Uddin,&nbsp;Shahid Uz Zaman,&nbsp;Krishnakant B. Budhavant,&nbsp;Abdus Salam","doi":"10.1002/joc.8800","DOIUrl":"https://doi.org/10.1002/joc.8800","url":null,"abstract":"<div>\u0000 \u0000 <p>In South Asia, our understanding of atmospheric aerosols and their optical properties is limited, posing a challenge to comprehending climate change dynamics. This study characterises aerosol optical properties, radiative properties, black carbon (BC) and ozone (O₃) at seven South Asian locations, including Nam Co (Tibetan Plateau, TP), Dhaka, Bhola (Bangladesh), and Hanimaadhoo, Kashidhoo, Male' and Gan (Maldives). The study utilises columnar aerosol data from the Aerosol Robotic Network (AERONET) and reanalysis data from Modern-Era Retrospective Analysis for Research and Applications (MERRA-2) from 2001 to 2020. Notably, during the winter, the highest Aerosol optical depth (AOD) levels were observed in Dhaka (1.0 ± 0.5) and Bhola (0.8 ± 0.4) among these seven locations. BC concentrations in Dhaka ranged from 2.1 to 2.8 μg m⁻³, while Bhola recorded concentrations between 1.4 and 2.1 μg m⁻³. O₃ levels across Maldives sites remained consistent, with values ranging between 314 and 345 dobson units (DU), surpassing those in Bangladesh and TP. The analysis shows a significant difference in the rate at which the atmosphere heats (HR) up due to aerosols. Higher heating rates were observed over Kashidhoo during the post-monsoon and winter seasons, while lower values were seen during the pre-monsoon and monsoon seasons, compared with Hanimaadhoo and Male'. It is important to note that Bangladesh had higher HR values than the Maldives. This study helps us better understand the impact of atmospheric aerosols on South Asia's climate and the different seasonal patterns.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improvements in the Seasonal Prediction of the Mid-Summer Drought Based on the North American Multimodel Ensemble","authors":"David Maximiliano Zermeño-Díaz,&nbsp;Pallav Ray","doi":"10.1002/joc.8798","DOIUrl":"https://doi.org/10.1002/joc.8798","url":null,"abstract":"<p>Skillful prediction of the Mid-Summer Drought (MSD) is important for various socioeconomic sectors in southern Mexico, Central America and the Caribbean. However, operational forecasting errors of the MSD have rarely been evaluated systematically. In this study, we address this research gap by examining operational forecasts of the MSD derived from the North American Multimodel Ensemble (NMME; 1991–2020). We assess these forecasts before and after applying a Model Output Statistics (MOS) scheme based on Canonical Correlation Analysis (CCA). Before applying MOS, only a couple of forecasts exhibited a bimodal signal between July and September, but none of them reproduced the particular signals of the MSD; they generally suffered from two main errors: excessively weak precipitation during the June–September season (particularly in June) and a weak peak in July instead of a relative minimum. While the root cause of these errors can be associated with warm sea surface temperature (SST) bias in the tropical eastern Pacific and cold SST bias in the Gulf of Mexico, Caribbean Sea and northwestern tropical Atlantic, their immediate cause is an erroneous evolution of the eastern Pacific Intertropical Convergence Zone (ITCZ). During June and September, the eastern Pacific ITCZ remains too far south near the equator, while in July and August it expands and intensifies but stays too close to the coasts of southern Mexico and Central America, failing to migrate westward. After applying MOS, the forecasts showed high skill scores during the onset of the MSD (July and August) but not in the months before and after (June and September). As revealed by the CCA analysis, this improved skill is due to the MOS-corrected forecasts' improved representation of a key relationship: drier MSD episodes are associated with a stronger westward SST gradient between the eastern tropical Pacific Ocean and the Caribbean Sea. Models that adequately capture this relationship exhibit reduced uncertainty in forecasting MSD intensity. This finding can provide a valuable pathway to mitigate uncertainties in projecting future changes in MSD intensity under different climate change scenarios.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8798","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of the Pacific Decadal Oscillation and El Nino-Southern Oscillation on Regional Precipitation Concentration","authors":"Yinhong Kang,&nbsp;Tiefeng Ni,&nbsp;Shuai He,&nbsp;Zihua Cao,&nbsp;Guixiong Wu,&nbsp;Jianghao Tong,&nbsp;Zhaokai Ye","doi":"10.1002/joc.8789","DOIUrl":"https://doi.org/10.1002/joc.8789","url":null,"abstract":"<div>\u0000 \u0000 <p>Exploring the regional precipitation concentration index (PCI) provides profound insights into the distribution patterns of rainfall within a specific area. This study utilised daily precipitation data from Sichuan Province to investigate the spatiotemporal variations of PCI on annual and seasonal scales, as well as its potential relationships with the Pacific Decadal Oscillation (PDO) and El Niño-Southern Oscillation (ENSO). A modified Mann-Kendall test was employed to identify significant trends in the PCI. Furthermore, this study examined the relationships between the daily concentration index (CID) and the monthly concentration index (CIM), along with their spatiotemporal characteristics. The remote potential relationships between PCI and ENSO/PDO were analysed using cross wavelet transform and correlation test. The results indicate that: (1) A significant positive correlation exists between CID and CIM in the central Sichuan basin (CB) region, while this correlation is not significant in other regions. (2) There is a non-significant decreasing trend in precipitation concentration across Sichuan Province, primarily observed in spring. (3) The spatial and temporal distribution of PCI in Sichuan Province becomes increasingly variable and irregular with decreasing longitude and increasing elevation. (4) The negative impact of ENSO and PDO on annual PCI and autumn PCI significantly diminish from east to west. In summer, the potential negative impact of PDO on Seasonal precipitation concentration index (SPCI) significantly decreases from north to south. This study provides key information to reveal the variations and potential influences of meteorological and hydrological processes in Sichuan Province.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climatological Analysis of Variability in Snow Cover Features Across Iran During 1981–2022","authors":"Marzieh Sadeghi,&nbsp;Hossein Asakereh,&nbsp;Mohammad Darand","doi":"10.1002/joc.8780","DOIUrl":"https://doi.org/10.1002/joc.8780","url":null,"abstract":"<div>\u0000 \u0000 <p>The present study aimed to conduct a climatological analysis of snow cover variability in Iran using daily snow cover data collected from meteorological stations between 1 January 1981, and 31 December 2022. Stations were selected based on the criterion of having at least one day of snowfall over 1 cm in depth during the study period. The analysis focused on nine key indices: First snow cover day (FSC), last snow cover day (LSC), snow cover duration (SCD), mean duration of continuous snow cover (SCDmean), maximum duration of continuous snow cover (SCDmax), snow-free days (SFD), snow spell duration index (SSDI), number of snow cover events (NSC) and depth of snow cover (DSC). The temporal analysis revealed substantial variability in the FSC, ranging from October 10th in regions above 2000 m in the northwest to January 30th along the Iranian coast of the Caspian Sea. The LSC also varied from January 20 to April 20 in the low-elevation regions of the Zagros in the south to April 20 in the Alborz in the North. Moreover, the SCD was over 160 days a year in the Alborz mountain in the north. Spatial analysis indicated a significant correlation between snow cover indices and elevation, longitude and latitude in Iran's mountainous regions. Results indicated a notable increase in FSC in most parts of the country, alongside a decreasing trend in LSC. On average, FSC advanced by 2 days per decade towards winter, while LSC shifted approximately −0.82 days per decade towards winter. Additionally, SCD, NSC, DSC and SSDI exhibited decreasing trends while SFD increased.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trends and Variability of Temperatures in the Eastern Province of Rwanda","authors":"Michel Rwema,&nbsp;Bonfils Safari,&nbsp;Marko Laine,&nbsp;Mouhamadou Bamba Sylla,&nbsp;Lassi Roininen","doi":"10.1002/joc.8793","DOIUrl":"https://doi.org/10.1002/joc.8793","url":null,"abstract":"<p>This study investigates air temperature trends and variability over the Eastern Province of Rwanda and its derived near-homogeneous zones for 1983–2021. Near-homogeneous zones are obtained using the K-means clustering method to classify annual long-term means of rainfall and minimum, maximum and mean temperatures from 570 grid cells in the Eastern Province. Changes in monthly, seasonal and annual minimum, maximum, and mean temperatures are computed with a 95% confidence interval using a dynamic linear state-space model. This model effectively captures temporal patterns by linking hidden states that evolve over time to observed measurements while accounting for random fluctuations. Additionally, temporal variability is assessed using standard deviation. In Eastern Rwanda, annual minimum and mean temperatures have risen to 2.95°C (confidence interval: [1.64–4.45]) and 1.87°C (confidence interval: [0.61–3.19]), respectively. A significant increase in seasonal minimum temperature is observed in all seasons, the June–July–August season presenting the highest value of 3.37 [1.75–4.81]°C. The seasonal mean and the annual maximum temperature have not significantly changed. Minimum temperature displays notable nonlinearity in its time-varying trends, remaining relatively stable during 1990–2010 before experiencing a pronounced warming trend thereafter. Over the three identified zones (1. Northwestern, 2. Central and 3. Southeastern), a significant increase in seasonal and annual minimum temperature is observed in the Northwestern and Southeastern zones. The highest increases are in the Northwestern zone, June–July–August season having 4.07 [2.26–6.08]°C. The seasonal and annual minimum, maximum and mean temperatures vary relatively little, with a standard deviation of less than 1°C in all zones. The seasonal and annual minimum and mean temperature increase over the Northwestern zone is dominant over the Eastern Province. This study identifies climate change vulnerable areas in Eastern Rwanda, offering vital insights to guide policy and decision-makers in supporting affected communities while enhancing resilience and informing future climate research.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8793","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-Term Variability of Fog in Poland","authors":"Olga Zawadzka-Manko,&nbsp;Krzysztof M. Markowicz","doi":"10.1002/joc.8784","DOIUrl":"https://doi.org/10.1002/joc.8784","url":null,"abstract":"<div>\u0000 \u0000 <p>Fog phenomena are frequent natural hazards, sensitive to meteorological parameters, with significant impacts on visibility and transportation that may evolve under ongoing climate change. This study analyzes the spatial transformation and trends in fog properties in Poland from 1973 to 2020. The research utilises synoptic measurements from IMGW-PIB, the Integrated Surface Database, and long-term emissions data from the Peking University repository. To evaluate the influence of various factors on fog properties, a Random Forest Regressor model was employed. Results indicate regional variation in fog frequency, with higher occurrences (69–77 days/year) at certain stations (Zielona-Góra, Chojnice, Kielce) and lower frequencies in coastal areas (below 40 days/year). The duration of fog events ranges from 3.7 to 6.1 h/day, with visibility between 380 and 590 m. Trends in fog days shifted from a decline of 8.4 days/decade before 1990 to 4.4 days/decade afterwards. While central and northern Poland experienced a reduction in fog days pre-1990, an increase was observed in the southern regions. Post-1990, fog duration decreased significantly (−0.45 h/decade). Meteorological factors were found to influence fog occurrence strongly. Days with low wind speeds (&lt; 3 m/s) showed a moderate correlation (0.47) with annual fog days, while mountainous regions and elevation had strong positive correlations (0.91 and 0.84, respectively). High humidity (100%) correlated moderately (0.42), whereas temperature exhibited a negative correlation (−0.78). The Random Forest model effectively predicted fog days, achieving an <i>R</i>² score of 0.64 for stations outside mountainous regions and 0.95 when including all stations, with minimal changes in the root mean square error (12 to 12.5 days/year).</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Catalogue and Analysis of Extraordinary Precipitation Events in the Spanish Mainland, 1916–2022","authors":"José Carlos Gonzalez-Hidalgo,&nbsp;Santiago Beguería,&nbsp;Dhais Peña-Angulo,&nbsp;Víctor Trullenque Blanco","doi":"10.1002/joc.8785","DOIUrl":"https://doi.org/10.1002/joc.8785","url":null,"abstract":"<p>Catalogues of past hazardous events are essential for understanding their magnitude, frequency, geographical distribution and underlying mechanisms. Such compilations provide critical data for identifying patterns, improving predictive models, and enhancing preparedness, thereby contributing to the mitigation of future risks and facilitating effective adaptation to climate-related hazards. In this article, we present the first comprehensive catalogue of extraordinary precipitation over the Spanish mainland, spanning more than a century. This work provides valuable insights into spatial and temporal patterns of these events. We compiled monthly maxima of daily precipitation (Rx1day) exceeding 100 and 200 mm by combining the documentary collections of the AEMET National Climate Data Bank (1916–2022) with newly digitised data from the Annual Summaries of Observation Books (1916–1950). As a result, this dataset represents the most extensive and detailed collection of extraordinary precipitation events in the region. It includes 19,184 monthly maxima records above 100 mm from 4325 observatories, occurring across 4814 days (events). Additionally, there are 1130 records exceeding 200 mm, grouped into 530 days and recorded in 664 observatories. As anticipated, extraordinary rainfalls were most frequent in autumn, while summer recorded the lowest number of events. These events occurred across nearly all regions, although a higher concentration were observed near coastlines. This is particularly the case of records and events over 200 mm, which concentrated along the Mediterranean arc. We identified five spatial patterns that correspond with specific weather types. Beyond atmospheric circulation, the topography played a critical role in determining the spatial extension of extraordinary precipitations. The newly digitised dataset is available at https://digital.csic.es/handle/10261/354840, accompanied by a collection of maps of daily events. Raw data from the AEMET's National Climate Data Bank are subject to a licenced agreement.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8785","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controls of Climate and Catchment Behaviour on Runoff Response Across Large-Scale Sample","authors":"Yang Mingjuan,&nbsp;Gong Zhanlong,&nbsp;Pang Tao","doi":"10.1002/joc.8760","DOIUrl":"https://doi.org/10.1002/joc.8760","url":null,"abstract":"<div>\u0000 \u0000 <p>Recent research has extensively examined the response of runoff to climate change. However, the physical mechanisms underlying runoff responses in changing climate conditions remain poorly understood. To address this gap, this study uses measured streamflow and meteorological data from the public GAGES-II database to investigate the physical controls influencing runoff responses to climate and catchment behaviour across more than 1000 catchments in the contiguous United States. Eighteen flow signatures and 56 indicators related to catchment attributes were analysed and grouped using a hierarchical clustering method, resulting in the classification of the 1000+ catchments into ten clusters, each with distinct characteristics. Within each cluster, we explored the patterns of runoff response, focusing on runoff changes and sensitivity for each flow signature and catchment attribute. Our findings indicate that flow signatures such as runoff ratio, annual runoff, and the 95th percentile runoff significantly affect total runoff changes. Evapotranspiration displays a trade-off relationship with overall runoff changes but shows a synergistic relationship with Richard Baker's rapid runoff. Furthermore, the runoff changes driven by catchment attributes align with the total changes, suggesting that catchment behaviour predominantly influences runoff generation processes. Climate factors tend to exert greater influence in arid and semi-arid catchments.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced Influence of April Snow Cover Over the Eastern Tibetan Plateau on the Variability of West China Autumn Rain After 2000","authors":"Junyu Wang,&nbsp;Botao Zhou,&nbsp;Hua Li","doi":"10.1002/joc.8788","DOIUrl":"https://doi.org/10.1002/joc.8788","url":null,"abstract":"<div>\u0000 \u0000 <p><b>“</b>West China Autumn Rain” (WCAR), which represents the second peak in local precipitation following the summer, frequently causes floods and related secondary disasters, posing significant challenges to the sustainable development of economy and society. As such, a better understanding of the variability in WCAR is crucial for disaster prevention and mitigation. This study, based on the observed precipitation and reanalysis data, addresses the relationship of the WCAR variability with the April snow cover over the eastern Tibetan Plateau from 1981 to 2021, and highlights a notable shift from an insignificant to a significant correlation after 2000. During 2000–2021, the distinctive dipole pattern of the eastern Tibetan Plateau snow cover (TPSC) in April—characterised by negative anomalies in the south and positive anomalies in the north—corresponds with an intensification of the South Asian High (SAH) in the subsequent autumn. This, in turn, induces a northward shift of the East Asian jet (EAJ) and a westward displacement of the western Pacific subtropical high (WPSH), concurrent with an enhancement of moisture transport into West China, providing favourable dynamic and moisture conditions for the increase in WCAR. The warming of soil temperatures in April over the southeastern Tibetan Plateau, driven by increased shortwave radiation and propagating into autumn, is hypothesized to bridge the lagged influence of snow cover on the above atmospheric circulations. In contrast, during 1981–1999, due to decreased interannual variability of snow cover, the April TPSC shows no substantial effect on the WCAR-related atmospheric circulations, hence weakening its connection with the WCAR variability.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revising Flood Return Periods by Accounting for the Co-Occurrence Between Floods and Their Potential Drivers","authors":"Kanneganti Bhargav Kumar,&nbsp;Rajarshi Das Bhowmik,&nbsp;Pradeep P. Mujumdar","doi":"10.1002/joc.8783","DOIUrl":"https://doi.org/10.1002/joc.8783","url":null,"abstract":"<div>\u0000 \u0000 <p>The return period of floods can be influenced by the extreme values of their potential drivers, which may vary among catchments. Understanding the risk and the associated changes in return periods due to these extreme values of drivers is therefore of interest in flood hydrology. In this study, floods are considered as compound events resulting from a combination of non-independent factors. The return periods of these events are estimated using joint distribution functions, accounting for the dependence of flood peaks and their potential drivers in two distinct catchments: (i) an inland catchment-Warunji Catchment, Krishna basin, India, and (ii) a coastal catchment-Usk catchment, United Kingdom (UK). The annual maximum (AM) rainfall, soil moisture and storm surge are considered as potential drivers of floods and their variations in time of occurrence are calculated to understand co-occurrence patterns. The pairwise co-occurrence frequency and dependence are estimated, and joint distribution is calculated with the survival copula distribution function. The results indicate that AM values of the variables tend to co-occur within a short time window, signifying that the flood risk changes with the extreme values of drivers. The maximum values of the AM series of drivers are observed in the same year as the largest flood in the series. The joint return periods of flood events show significant variations from their univariate estimates in both catchments, which have different flood-generating mechanisms. This work re-emphasises the findings in recent literature that the traditional univariate risk assessment methods based only on flood peak information may substantially underestimate/overestimate the risk of floods by neglecting the effects of their potential drivers and that a multivariate viewpoint is imperative for assessing the risk of floods.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}