International Journal of Climatology最新文献

{"title":"Has the Extent of Summer Monsoon Rainfall Activity Increased in Iran? A Long-Term Analysis of Trends and Connection With Monsoon Indices","authors":"Mohammad Rezaei,&nbsp;Farshad Pazhoh","doi":"10.1002/joc.8852","DOIUrl":"https://doi.org/10.1002/joc.8852","url":null,"abstract":"<div>\u0000 \u0000 <p>In the summer of 2022, Iran experienced severe flooding that caused extensive damage to infrastructure, agriculture, and residential areas. This event prompted an investigation into whether the frequency and extent of severe summer flooding in Iran have increased due to global warming. This study investigates long-term trends in Widespread Rainy Days (WRDs) in Iran during the summer season (June to September) and analyses their correlation with Indian summer monsoon indices, specifically the Convective Index (CI) and U-wind Index (UI). Reanalysis data, including precipitation, Sea Level Pressure (SLP), and Geopotential Height (GPH) from 1836 to 2015, were used for the analysis. WRDs in Iran were calculated for each year using the connected components labelling method. The results indicate a positive correlation between precipitation and WRDs with the CI, implying that an increase in Outgoing Longwave Radiation (OLR) in the Bay of Bengal leads to higher rainfall and more WRDs in Iran. Amongst all observed correlations, the highest correlation (<i>r</i> = 0.58) was found in southeastern Iran. On days with the highest CI values, negative anomalies in sea level pressure (SLP) and 850-hPa geopotential height (GPH) are observed. These anomalies, along with increased humidity advection, contribute to the occurrence of WRDs in Iran. Conversely, Iran's summer rainfall shows a negative correlation with the UI. On days with the highest UI values, no negative anomalies were observed in SLP and 850-hPa GPH, and reduced humidity advection resulted in the absence of WRDs in Iran. The study also reveals that the majority of WRDs occur in June, with the highest density observed in the southeast region of Iran. The Mann–Kendall test indicates a decrease in WRDs in Iran, particularly in June (<i>R</i>² = 17%) and September (<i>R</i>² = 24%). Whilst July and August also exhibit a decline, the trend is relatively weaker (<i>R</i>² = 2%). These findings demonstrate a statistically significant decline in WRDs over the 180-year period, contradicting the hypothesis of increased monsoon rains in Iran due to global warming.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315113","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":"Evaluating the Influence of Climate and Topography on Mount Kilimanjaro Vegetation: A Comparative Analysis Using MODIS NDVI and Weather Station Data (2000–2022)","authors":"Ehsan Khalefa,&nbsp;Nicholas Pepin,&nbsp;Richard Teeuw","doi":"10.1002/joc.8861","DOIUrl":"https://doi.org/10.1002/joc.8861","url":null,"abstract":"<p>Climatic and topographic factors are critical for influencing vegetation cover, especially in mountainous areas. This study investigates vegetation dynamics in the South-Western (SW) and North-Eastern (NE) zones of Kilimanjaro over the past two decades. We used the Moderate Resolution Imaging Spectroradiometer (MODIS) data, focusing on Normalised Differential Vegetation Index (NDVI) trends and their relationship with climatic and topographic factors. The NDVI dataset for 2000–2022 was combined with Digital Elevation Model (DEM) data and corresponding climatic and topographic indices across different elevation zones. Time series analysis shows positive NDVI trends in both zones, with the NE zone exhibiting more significant increases, particularly at lower elevations (665–1800 m), while the SW zone shows positive trends mainly at higher elevations (4000–5000 m). Climatic analysis reveals a complex relationship between NDVI, temperature, and humidity, with the NE zone showing more consistent correlations and the SW zone displaying more variability, especially in the montane forest zone. A Random Forest (RF) regression model highlights the differing importance of climatic and topographic factors: elevation and temperature are the most significant predictors of NDVI in the NE zone, while humidity is the key factor in the SW zone. Overall, these results highlight the differential impacts of climate and topography on vegetation dynamics in the NE and SW zones, reflecting the complex interplay of these factors in influencing vegetation health and distribution. Future work will involve studying the effects of vegetation cover changes and climate heterogeneities on water availability on the slopes of Kilimanjaro to support effective water resource management.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8861","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144646744","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":"Characterising Cold-Dry and Cold-Wet Compound Events in the United Kingdom","authors":"Kanzis L. Mattu,&nbsp;Christopher J. White,&nbsp;Hannah Bloomfield,&nbsp;Joanne Robbins","doi":"10.1002/joc.8859","DOIUrl":"https://doi.org/10.1002/joc.8859","url":null,"abstract":"<p>Compound cold extreme weather events—co-occurring multivariate events—have been defined as either cold-dry (CD) or cold-wet (CW) depending on the absence or presence of heavy precipitation. Both event types induce varying levels of social and economic impacts across multiple sectors such as health, transport and energy depending on which type of event is experienced. In this study, we characterise these CD and CW events in the United Kingdom (UK) using a location-specific percentile approach and assess their relationship with a set of 30 UK-specific weather patterns to determine the event drivers. The results show that there are up to 14 CD days per winter season in the west of the study region compared to 4–8 CD days in the east. The inverse is shown for CW with 0–1 days per winter season in the west and 2–3 days in the east. CD events are predominantly driven by anticyclonic weather patterns (which are classified in the negative North Atlantic Oscillation regime), and CW days are driven by cyclonic weather patterns. This study provides evidence that a location-specific approach alongside weather pattern analysis could be adopted as a tool for impact-based forecasting at a medium-range lead time to forecast CD and CW events.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8859","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144646975","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":"Observational Characterisation of Fog Events Over the Main Argentine Airports","authors":"Melina Sol Yabra,&nbsp;Ramón de Elía,&nbsp;Luciano Vidal,&nbsp;Matilde Nicolini","doi":"10.1002/joc.8858","DOIUrl":"https://doi.org/10.1002/joc.8858","url":null,"abstract":"<div>\u0000 \u0000 <p>This study characterises fog events across 13 major airports in Argentina from 2000 to 2019, providing insights into their occurrence and impact on aviation. Using the complete surface synoptic observations (SYNOP) database from the National Meteorological Service of Argentina, this research improves upon previous studies that relied on incomplete meteorological aerodrome report (METAR) datasets. The analysis evaluated various criteria to identify fog events, accounting for their duration, intermittency, and aviation impact. Key findings reveal significant regional variability in fog characteristics, influenced by diverse latitudes, topographies, and environmental conditions. Metrics such as monthly occurrence, onset and dissipation times, duration, and visibility median and minimum were analysed. An extreme event identification criterion highlighted aviation-disruptive fog events, comprising 7%–20% of cases. As a critical issue for flight operations, airports prone to persistent fog events over consecutive days were also identified, showing undiscovered fog's behaviour that wasn't addressed in previous analysis. All results were associated with theoretical behaviours linked to physical mechanisms influencing fog formation and dissipation. These findings provide valuable tools for improving fog forecasting in Argentina and underscore the need for further research into the physical processes governing fog's life cycle to enhance aviation safety and operational efficiency.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144646948","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":"Copula-Based Approach to Nonstationary Bivariate Frequency Analysis of Short-Duration Precipitation Extremes in Huaihe River Basin, China","authors":"Huanyu Yang,&nbsp;Pengcheng Xu,&nbsp;Dong Wang,&nbsp;Vijay P. Singh,&nbsp;Zhilang Zhang,&nbsp;Miao Lu","doi":"10.1002/joc.8855","DOIUrl":"https://doi.org/10.1002/joc.8855","url":null,"abstract":"<div>\u0000 \u0000 <p>The risk of extreme rainfall events has increased due to climate change, necessitating the risk assessment of extreme rainfall events under a nonstationary framework. Since short-duration extreme rainfall events are more sensitive to environmental changes, and the current research on the risk of continuous short-duration extreme rainfall events is insufficient, this study presents a methodological framework for assessing the risk of short-duration rainfall extremes using a nonstationary model across the Huaihe River Basin in China from 1963 to 2015. The methodology includes the following components: (1) A quantile-based approach was used to identify the short-duration extreme rainfall events. (2) The risk of short-duration extreme rainfall events caused by climate change was calculated using nonstationary bivariate models and compared with those from stationary models. (3) The design values corresponding to the most-likely design event at different average annual reliability (AAR) were calculated based on copula models. The results illustrated that the intensity of rainfall duration and total rainfall of short-duration extreme rainfall events in most stations increased significantly after 2000. The width of the 90% confidence interval for the design values estimated based on AAR increased under both nonstationary marginal distributions and nonstationary copula models, indicating that the calculation of the design values will be affected in both scenarios. Therefore, it is necessary to use nonstationary bivariate models to assess the risk of short-duration extreme rainfall events under climate change. Overall, this study provides a systematic framework for conducting nonstationary risk assessments of short-duration extreme rainfall events.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315336","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":"Climate Change Hotspots for Türkiye","authors":"Nazan An,&nbsp;M. Tufan Turp,&nbsp;Elif Bayindir,&nbsp;Yagmur Akverdi,&nbsp;Zeynep Nur Mirza,&nbsp;M. Levent Kurnaz","doi":"10.1002/joc.8825","DOIUrl":"https://doi.org/10.1002/joc.8825","url":null,"abstract":"<div>\u0000 \u0000 <p>Depending on various indicators, climate change may affect each region globally at varying risk levels. Therefore, identifying the ‘hotspots’ most likely to be affected by climate change in the future is a crucial step in ensuring those areas rapidly adapt to it. The study estimated the Standard Euclidean Distance (SED) for identifying hotspots of Türkiye using high-resolution climate projection data (10 × 10 km) and examined regional vulnerability in the long-term future over a 75-year period (2024–2099). The projections were made using RegCM4.4 driven by MPI-ESM-MR under the optimistic (RCP4.5) and pessimistic (RCP8.5) scenarios. The findings indicate that the hotspot regions in Türkiye are Southeastern Anatolia, Eastern Anatolia and the Mediterranean for RCP4.5, and Southeastern Anatolia, Eastern Anatolia, the Mediterranean and Central Anatolia for RCP8.5. The most critical indicators, however, are temperature-related indicators (i.e., Mean Air Temperature, Hot Seasons and Temperature Variability). Based on the findings, it is necessary to take preventive measures, particularly in highly vulnerable regions, to minimise potential damage. Additionally, multi-model ensemble studies should be applied to reduce the uncertainties and model-related variability, as well as to provide robust evidence of climate change.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256120","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":"Intraseasonal Oscillations and Hydroclimate of Northern South America, Central America and Mexico","authors":"Alejandro Builes-Jaramillo,&nbsp;Johanna Yepes,&nbsp;Hernán D. Salas,&nbsp;Juan M. Bedoya-Soto,&nbsp;Paris Rivera,&nbsp;Juliana Valencia,&nbsp;Alejandra M. Carmona","doi":"10.1002/joc.8848","DOIUrl":"https://doi.org/10.1002/joc.8848","url":null,"abstract":"<div>\u0000 \u0000 <p>We examine the influence of intraseasonal variability (10–90 days) on hydroclimatic variables across Northern South America, Central America and Mexico. This variability is driven by planetary and tropical oscillations, including Kelvin waves, Tropical Easterly Waves, Mixed Rossby-Gravity Waves and the Madden–Julian oscillation, all of which display distinct signals in the wavenumber–frequency power spectra. Our findings reveal that intraseasonal variability accounts for 10%–35% of the total variance, depending on the specific location, with Kelvin waves being the largest contributors to the outgoing longwave radiation variance in the study region. Additionally, we observed positive and negative precipitation anomalies across the region associated with each oscillatory process, which can be linked to anomalies in moisture transport and convection within the atmospheric column. The Madden–Julian oscillation contributes 10%–12% of precipitation over continental areas, while Tropical Easterly Waves and Mixed Rossby-Gravity waves account for approximately 40% of the precipitation over the continent. These findings offer new insights into the spatial and temporal patterns within the region. A deeper understanding, diagnosis and prediction of this timescale are crucial for economic sectors such as agriculture, energy generation, risk management and water resources.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315049","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":"Risk Assessment of Extreme Precipitation in Northwest Iran in the Light of Changing Climate","authors":"Poya Fakour,&nbsp;Zbigniew Ustrnul,&nbsp;Agnieszka Wypych","doi":"10.1002/joc.8854","DOIUrl":"https://doi.org/10.1002/joc.8854","url":null,"abstract":"<p>The objective of this study is to conduct a regional risk analysis based on extreme precipitation trends at annual and seasonal time scales. It evaluates the trends of precipitation extremes over the Northwest of Iran, covering 600,000 km². ECMWF-ERA5 reanalysis precipitation data with a relatively high spatial resolution of 0.25° × 0.25° and daily temporal resolution are used for the long-term historical period from 1941 to 2020. The provided risk assessments are based on the integration of the special distribution of trends for 10 selected extreme precipitation indices (EPIs), which were assessed with a non-parametric Mann–Kendall test at the significance level of <i>α</i> = 0.05. Additionally, the difference in precipitation for the recent climate reference period (1991–2020) was compared to a subperiod 1941–1970, pursuing to distinguish shifts in precipitation patterns. The findings have found a meaningful increase in the frequency of daily heavy precipitation events over the explored period, specifically in the few latter decades. The trends reveal primarily positive patterns, with many being statistically significant. Furthermore, in some regions, total rainfall has increased by nearly 25% over the past three decades. The highest number of events occurs during the winter (DJF) followed by the spring (MAM) season. Nevertheless, looking at the monthly timescale, March records the highest number of extreme precipitation events. The strongest positive trend in intensity and frequency is associated with the autumn season (SON), particularly October and November in this region. Moreover, the highest number of grid points with notable positive trends is observed during autumn on the seasonal timescale and in November on the monthly timescale. Whilst the results of the annual survey show that 56.5% of the region is at risk of extreme precipitation, this percentage grows to 80.3% on the seasonal scale (SON), which highlights the areas with a higher probability of the occurrence of extreme precipitation events. Overall, the combined results of the EPIs trends indicate a significant shift towards more intense and frequent precipitation on interannual scales. Notably, most of this region can be classified as a susceptible area to extreme precipitation events and therefore at a high probability of flash floods, especially during the autumn season.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8854","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315050","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":"Drought to Flood to Drought: A Review of Definitions of Precipitation Whiplash Events, What Causes Them and Their Impacts Over the Continental United States","authors":"Esther Mullens,&nbsp;Johanna Engström","doi":"10.1002/joc.8850","DOIUrl":"https://doi.org/10.1002/joc.8850","url":null,"abstract":"<p>Precipitation whiplash, the rapid shift from drought to flooding, or vice versa, exacerbates the impact of both extremes compared to if they were to occur separately. The recognition of these types of events is relatively recent, and event precursors, driving meteorology and impacts are poorly understood. In response to this, this review summarises the current state of science of precipitation whiplash events in the United States, analysing event definitions, driving meteorology, impacts and the spatial distribution of the studies. Definitions vary considerably in temporal extent, from the transition between wet and dry conditions happening in less than a week to over a year. The climatological drivers and meteorological conditions creating precipitation whiplash events show significant diversity as well, both due to the varying event definitions and also due to the different geographical settings and range of scales of the studies. A wide range of definitions, drivers and impacts are described here, allowing researchers to better understand the phenomenon that is precipitation whiplash while also creating a foundation for future studies to delve deeper into the topic.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8850","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315052","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":"Reconciling Different Views on the Onset of Boreal Summer Monsoon: The Example of Thailand","authors":"Vincent Moron,&nbsp;Chalump Oonariya,&nbsp;Chaowat Siwapornchai,&nbsp;John L. McBride","doi":"10.1002/joc.8862","DOIUrl":"https://doi.org/10.1002/joc.8862","url":null,"abstract":"<p>The onset of the rainy season in monsoonal climates is a critical stage of the crop calendar, and its real-time monitoring, forecast and understanding are fundamental tasks for either end-users, stakeholders and experts in climatology. Onset may be ideally defined as a sharp switch between opposite winds in lower and upper troposphere and/or a sudden increase of rainfall, nearly synchronous over a sufficiently large scale. Thailand is an excellent field to illustrate the different facets of the onset. We used the daily rainfall over a network of 75 stations (1981–2021) and upper- and lower-level winds to define local- to country-scale onsets. Some significant pre-monsoon rainfall occurred 1–4 weeks in the mean before the clear settlement of the monsoon circulation occurring usually in mid-May. These pre-monsoon rainfall are not systematically purely local and may sometimes start sustained rainfall or be interrupted by a long dry spell, especially over Central Thailand. The use of a criterion of post-onset dry spell allows us to filter out some of the ‘false’ onsets, i.e., when the initial 3-day wet spell receiving at least 30 mm is followed by a 14-day dry spell in the following 30 days. This definition optimises the amount of interannual covariance amongst the rain gauges but is clearly not optimal for the end-users, because 30 days are needed to declare the onset at local scale and even more at the province to country scale. An operational solution discards the dry spell criteria over a reduced set of only five stations located on the windward southern Peninsula. Such definition is similar to the ‘Monsoon over Kerala’ for the Indian monsoon, and this onset occurs around 9 April in mean, and its interannual variations are highly correlated (<i>r</i> = 0.72) with the spatially averaged local onsets over mainland Thailand &gt; 11° N.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 9","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8862","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144646900","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}