International Journal of Climatology最新文献

{"title":"Improved Identification of Extreme Rainfall Events in the Himalayan Foothills Using an Observation-Based Ensemble Precipitation Dataset","authors":"Anagha Peringiyil,&nbsp;Manabendra Saharia","doi":"10.1002/joc.70412","DOIUrl":"https://doi.org/10.1002/joc.70412","url":null,"abstract":"<div>\u0000 \u0000 <p>Extreme rainfall events (EREs) like cloudbursts in the Indian Himalayas are not only unpredictable in location and timing but also catastrophic, often leading to severe flooding and landslides. Detecting them is challenging as they often occur in remote locations without gauge stations or radar coverage. The existing 0.25° station-based deterministic product from the Indian Meteorological Department (IMD) systematically undercaptures these storms over the north-western Himalayas. This study tests whether finer-scale, terrain-aware interpolation can improve ERE detectability without adding new stations. We evaluate the 0.1° Indian Precipitation Ensemble Dataset (IPED), developed using the same station network as the IMD dataset but with an improved interpolation technique, against three benchmark datasets: 0.25° IMD, the 0.1° IMERG satellite and the 0.12° IMDAA reanalysis dataset. Using state-specific 99.90th percentile thresholds, the IMD dataset detects only 2, IMERG detects 3, while IPED captures 6 out of 24 EREs. Replacing the regional threshold with district-specific 99.90th-percentile values improves detection, with IPED capturing 7 out of 24 events, compared to 3 by IMD and 5 by IMERG. This study demonstrates that the new ensemble-based precipitation dataset, combined with a district-specific 99.90th percentile threshold, significantly enhances cloudburst-like ERE detection compared to the other datasets, such as IMD 0.25°, IMERG 0.1° and IMDAA 0.12°. Hourly IMDAA fields corroborate that every IPED-identified event spans a broad spatial footprint and persists for many hours, underscoring its hydrologic significance. The results show that (i) ensemble-based interpolation alone can markedly improve ERE detection, and (ii) locally tuned thresholds are essential in a region where rainfall gradients are steep. The combination of IPED and district-specific thresholds offers a practical, operationally viable framework for pinpointing cloudburst-scale hazards in the Himalaya, outperforming widely used gauge, satellite, and reanalysis alternatives.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373098","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":"Spatiotemporal Variation in Precipitation Extremes in South Ethiopia Based on PERSIANN-CDR and Gauge Data and Their Impact on Regional Sorghum and Teff Yields","authors":"Takele Lugo Fukka,&nbsp;Kritika Kothari,&nbsp;Getahun Tamiru Geletu","doi":"10.1002/joc.70407","DOIUrl":"https://doi.org/10.1002/joc.70407","url":null,"abstract":"<div>\u0000 \u0000 <p>Extreme precipitation events affect crop production and threaten food security, particularly in regions that depend on rainfed agriculture. Recurrent droughts and flash floods in Ethiopia have severely affected the farmers' ability to grow crops to meet their dietary needs, necessitating food assistance during climate shocks. The present study aimed to assess the effects of climatic extremes on crop yields in South Ethiopia. Particularly, the objectives were to assess spatiotemporal variation in extreme precipitation indices in South Ethiopia and analyse the relation between the indices and sorghum and teff yields. Long-term (1990–2021) data from 18 gauge stations and gridded PERSIANN-CDR data were used to compute extreme precipitation indices, viz. Standardised Precipitation Index (SPI), Standardised Precipitation-Evapotranspiration Index (SPEI), annual precipitation (PRCPTOT), highest amount of rainfall over one and five days (Rx1d and Rx5d), cumulative dry days (CDD) and cumulative wet days (CWD). For SPI and SPEI, three seasons relevant for sorghum and teff production were considered: <i>Belg</i> season (MAM), JASO and JJASON. The relationship between precipitation indices and crop yields (2003–2021) was assessed through correlation and relative importance analysis. Drought events were identified during 1992, 1999, 2000, 2009, 2011–2012, and 2015 based on MAM; and 1990, 1993, 2002–2004, 2009–2010, and 2015–2016 based on JASO and JJASON months. The number of drought years matched for majority of the cases between PERSIANN-CDR and gauge data. The PERSIANN-CDR, however, underestimated the magnitude of rainfall (mean PRCTOT 1099 vs. 1200 and Rx1d 34 mm vs. 55 mm) compared to the gauge data. Among the precipitation indices, sorghum yield was influenced by SPI-MAM, CDD, Rx5d, and Rx1d; whereas teff yield was influenced by SPI-MAM and SPI-JASO. Crop yields had a negative correlation with SPI-MAM and a positive correlation with CDD, which could indicate a detrimental effect of wet or flooding conditions on crop yields, or the result of farmers' adaptation of re-planting short-season sorghum variety after a dry <i>Belg</i> season. The study recommends further investigation into the relation of <i>Belg</i> season rainfall with crop yields, preferably with crop yield data at a finer spatial resolution representing different agroclimatic zones. The role of adaptation strategies such as flood-based farming and late planting of short-season sorghum varieties may be further explored. The study provides new insights enhancing the understanding of the complex relationship between precipitation extremes and crop yields, which may help prioritise areas for further monitoring and targeted studies for climate-smart agriculture strategies.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373472","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":"Characterisation of Drought and Wet Events in the Paraíba do Sul River Basin—Brazil","authors":"Gildo Rafael de Almeida Santana,&nbsp;Eliane Barbosa Santos,&nbsp;Maria Gertrudes Alvarez Justi da Silva,&nbsp;Vicente de Paulo Santos de Oliveira,&nbsp;Jader Lugon Junior","doi":"10.1002/joc.70400","DOIUrl":"https://doi.org/10.1002/joc.70400","url":null,"abstract":"<p>In Brazil, the Paraíba do Sul River Basin, spanning São Paulo, Minas Gerais and Rio de Janeiro, has experienced extreme precipitation events that, whether through excesses or deficits, have generated significant socioeconomic impacts in this key industrial and demographic region. Thus, this study aimed to analyse and characterise the occurrence and spatiotemporal patterns of drought and wet events in the Paraíba do Sul River Basin, using the Standardised Precipitation Index (SPI) at both 3-month and 12-month time scales. Based on historical rainfall data from 87 pluviometric stations spanning the period from 1963 to 2024, the SPI enabled the identification of short- and long-term hydrological patterns. To detect statistically significant trends, the non-parametric Mann-Kendall statistical test was used. The magnitude of the trends was obtained using the Sen's slope estimator. SPI-12 identified severe droughts in 1963 and 2014, with annual deficits above 500 mm, and the most intense wet event in 1983, with surpluses over 650 mm. SPI-3 confirmed recurrent seasonal droughts in 2014 and showed that wet events are not limited to the rainy season. Trend analysis revealed statistically significant changes in accumulated precipitation at the 5% significance level, with marked decreases in municipalities of São Paulo and Rio de Janeiro, such as Cunha-SP (−278 mm/year/decade), Nova Friburgo-RJ (−154.7 mm/year/decade), and Caçapava-SP (−113.5 mm/year/decade). In contrast, notable increases were observed in Minas Gerais, including Carangola-MG (+104.4 mm/year/decade), Patrocínio do Muriaé-MG (+105.4 mm/year/decade), and Miradouro-MG (+124.6 mm/year/decade). These results underscore a spatially heterogeneous pattern, reinforcing the need for adaptive and region-specific water resource management strategies.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.70400","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373569","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":"Rainfall Dynamics in Sri Lanka Over Five Decades (1970–2023): Implications for Agricultural Adaptation to Climate Change","authors":"N. S. Abeysingha,&nbsp;S. D. Madurapperuma Arachchige,&nbsp;M. S. V. Pathirana,&nbsp;Ram L. Ray","doi":"10.1002/joc.70415","DOIUrl":"https://doi.org/10.1002/joc.70415","url":null,"abstract":"<div>\u0000 \u0000 <p>Climate change is affecting agricultural productivity and economic stability across many parts of the world, but small islands like Sri Lanka are more vulnerable to the effects of climate change. As a result, assessing recent rainfall dynamics is crucial for developing effective climate adaptation measures. This study analysed rainfall data from 44 meteorological stations across Sri Lanka's dry, wet and intermediate climatic zones spanning 54 years (1970–2023) to evaluate rainfall dynamics. The analysis employed multiple statistical methods, including the coefficient of variation (CV), Precipitation Concentration Index (PCI), Standardized Precipitation Index (SPI), Mann–Kendall (MK) test with Sen's slope estimator and innovative trend analysis (ITA). Results revealed increasing annual rainfall trends at 79.5% of stations, with 40% showing statistically significant increases (<i>p</i> &lt; 0.05), particularly pronounced in the eastern and south-eastern areas of the dry and intermediate zones. Rainfall variability ranged from 12.9% to 35.4%, with higher variability concentrated in northeastern, eastern and southern regions, while the western wet zone exhibited lower rainfall variability and more consistent precipitation patterns. SPI analysis showed that 70% of years experienced near-normal conditions, while extreme wet and dry events occurred in 2.67%–4.13% and 2.4%–3.5% of years, respectively. Seasonal analysis demonstrated contrasting trends between monsoon systems: the northeast monsoon-dominated Maha season showed increasing rainfall at 82%–91% of stations, with 30% exhibiting significant increases (<i>p</i> &lt; 0.05). In comparison, the Yala season displayed increasing trends at only 56% of stations. Notably, intermediate zone stations (Wellawaya, Nikaweratiya) recorded higher wet year frequencies, while traditionally wet zone areas (Awissawella) experienced increased dry conditions, suggesting potential shifts in the climate zone boundary. These findings provide critical insights into agricultural adaptation to climate change, emphasizing the need for zone-specific adaptation measures.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373276","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":"Spatial and Temporal Dynamics of Drought, Heatwave and Compound Extremes in Saudi Arabia From 1984 to 2023: A Comprehensive Analysis","authors":"Mohammad Kamruzzaman","doi":"10.1002/joc.70404","DOIUrl":"https://doi.org/10.1002/joc.70404","url":null,"abstract":"<div>\u0000 \u0000 <p>Climate extremes are intensifying in arid regions, yet comprehensive assessments of compound drought–heatwave (CDHW) events remain limited in the Arabian Peninsula. This study presents the first station-based analysis of drought, heatwave and CDHW dynamics across Saudi Arabia over four decades (1984–2023), using daily observations from 23 meteorological stations. We identified droughts using the Effective Drought Index (EDI ≤ −1.0), defined heatwaves as ≥ 3 consecutive days exceeding the 90th percentile of daily maximum temperature and classified CDHW events when both conditions co-occurred. Trends were assessed using the modified Mann–Kendall test, with spatial patterns mapped via inverse distance weighting interpolation. Results reveal contrasting trends among event types. Mean annual drought duration reached 189.6 days in northern and central regions, with a non-significant national trend of +0.67 days year⁻¹ (<i>p</i> = 0.148). Heatwaves intensified significantly at +0.56 days year⁻¹ (+5.6 days decade⁻¹; <i>p</i> &lt; 0.001), with 74% of stations showing upward trends. Compound events also increased at +0.08 days year⁻¹ (+0.8 days decade⁻¹; <i>p</i> = 0.031), with 2019 recording the most severe conditions (&gt; 11 mean days). Decadal analysis shows drought intensification peaked during 2004–2013 (mean + 41.38% relative to 1984–1993 baseline), while heatwave increases were strongest during 2014–2023 (mean + 16.52%). Probability density analysis indicates a shift towards longer-duration extremes in recent decades, with maximum observed durations of 125 days for droughts, 50 days for heatwaves and 15 days for CDHW events. These findings demonstrate robust intensification of heatwaves and compound extremes, with central and northern regions experiencing the greatest vulnerability. The escalating frequency and severity of compound events underscore the need for enhanced monitoring systems and targeted adaptation strategies aligned with Saudi Vision 2030 climate resilience objectives.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373389","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":"Integration of SEBAL-Derived Evapotranspiration With Climate Change Projections to Assess Basin-Scale Water Resources and Crops Yield","authors":"Omidreza Mikaeili,&nbsp;Mojtaba Shourian","doi":"10.1002/joc.70398","DOIUrl":"https://doi.org/10.1002/joc.70398","url":null,"abstract":"<div>\u0000 \u0000 <p>Assessing the combined impacts of climate change on basin hydrology and crop production is essential for designing robust adaptation strategies in data-scarce arid regions. The Maroon Basin in southwestern Iran is a major agricultural zone affected by climate change and groundwater depletion. In this study, remote-sensing-based evapotranspiration (ET) derived from the Surface Energy Balance Algorithm for Land (SEBAL) was integrated with a deep-learning Long Short-Term Memory (LSTM) model and the SWAT hydrological–crop model to assess future water and yield responses under CMIP6 climate scenarios. SEBAL was applied to Landsat imagery to estimate spatially distributed ET for the historical period, and these estimates were used to train an LSTM model driven by daily minimum/maximum air temperature and precipitation. Bias-corrected CMIP6 projections under SSP1–2.6 and SSP5–8.5 were then used to generate daily ET scenarios for 2025–2070, which, together with the adjusted climate inputs, forced SWAT to simulate runoff and crop yields under future conditions. CMIP6 projections indicate substantial warming under both SSPs and seasonally varying changes in precipitation relative to the 1990–2014 baseline. SWAT simulations suggest mean annual runoff decreases by about 18%–22% and yields of three representative crops (alfalfa, wheat and apple) decline by up to ~40%–50%, with larger reductions under SSP5–8.5. Using SEBAL/LSTM-based ET instead of the default SWAT PET preserves the negative direction of change but yields systematically smaller magnitudes of runoff and yield reductions, indicating that improved ET representation moderates—but does not eliminate—adverse climate-change impacts. Yield results should be interpreted as scenario-based, internally consistent model responses (crop parameters were not tuned to local yield statistics). Additional uncertainty stems from the single GCM selection, the bias-correction approach, and the LSTM-based ET emulation. Nevertheless, the proposed SEBAL–LSTM–SWAT framework provides a practical approach for assessing the direction and relative magnitude of climate-change impacts on water availability and agricultural production in data-scarce, groundwater-stressed basins.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373537","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":"The Hydroclimate Paradox of the Indian Summer Monsoon Projections: Dual Amplification of Deficit and Excess Rainfall in CMIP6 Models","authors":"Akshay Kulkarni,&nbsp;P. V. S. Raju,&nbsp;Raghavendra Ashrit,&nbsp;Archana Sagalgile","doi":"10.1002/joc.70401","DOIUrl":"https://doi.org/10.1002/joc.70401","url":null,"abstract":"<div>\u0000 \u0000 <p>The Indian summer monsoon (ISM) governs the hydrological and agricultural foundation of South Asia, yet its response to anthropogenic warming remains uncertain and regionally diverse. Here we assess projected mean rainfall, variability and categorised monsoon extremes using six skill-selected CMIP6 models (BCC-CSM2-MR, CMCC-CM2-SR5, FIO-ESM-2-0, MCM-UA-1-0, MIROC6, TaiESM1) evaluated against the high-resolution IMD 0.25° dataset. Analyses are performed for the seasonal (JJAS) and monthly (June–September) scales under four Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5). Century long observed records reveal a quasi-stationary all-India mean monsoon rainfall, accompanied by a marked increase in interannual variability consistent with progressive amplification of hydroclimatic extremes. The CMIP6 multi-model ensemble (MME) reproduces this behaviour and projects a further 20%–35% rise in variability by the late 21st century. The coefficient of variation strengthens by 0.04–0.06 under high-emission scenarios, with statistically significant regime shifts detected around 2040–2060. Enhanced seasonality is evident, with June and September exhibiting pronounced drying (≈−2<i>σ</i>) and July–August showing intensified wet excursions (≥ +3<i>σ</i>). Categorical analyses indicate a 40%–60% increase in moderate and extreme excess monsoon years and a 20%–30% rise in deficit years, while event intensities strengthen to +4<i>σ</i> (wet) and –3<i>σ</i> (dry). These concurrent amplifications of surplus and deficit rainfall define a hydroclimatic paradox: simultaneous amplification of mean rainfall and interannual variability, leading to heightened probabilities of both surplus and deficit extremes. The findings directly tangled with the reduced seasonal predictability and challenges for reservoir management and crop planning, as evidenced by projected increases in extreme excess years and intensified deficits. The warming climate is reorganising the ISM towards a high-variance regime, challenging water security and adaptation planning across a region that depends critically on its seasonal rainfall predictability.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373295","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":"Polish Agriculture in the Face of Climate Change: Better or Worse?","authors":"Małgorzata Szwed,&nbsp;Małgorzata Holka","doi":"10.1002/joc.70387","DOIUrl":"https://doi.org/10.1002/joc.70387","url":null,"abstract":"<div>\u0000 \u0000 <p>The growing season is the period when weather conditions (e.g., precipitation, temperature, wind, etc.) support plant growth and development, thereby enabling agricultural production in a given region. This study examines the impact of climate change on agricultural conditions and production in Poland between 1961 and 2020, using data from 47 meteorological stations. The research period was divided into two parts: the baseline period (1961–1990) and the warming phase (1991–2020), the latter characterised by more rapid global warming. The paper analyses the characteristics of the growing season as well as unfavourable and extreme meteorological events occurring at different stages of plant development, including frost, prolonged or heavy rainfall, and atmospheric drought. The results indicate a significant increase in mean temperatures throughout the study period, which contributed to an extension of the growing season and of its specific stages, i.e., periods of intensive growth and ripening by 6, 10, and 14 days, respectively. However, the analysis of adverse meteorological characteristics/events during these phases generally reveals ‘no significant changes’ in their frequency or intensity. Summer drought remains the most critical threat to plant development and agricultural production. Although no increase in precipitation-free periods was observed during the ripening stage, rising temperatures accelerated evaporation and plant transpiration, thereby intensifying drought conditions and increasing associated risk.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148269334","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":"Long-Term Variability and Spatial Differentiation of the Frost-Free Period in Iceland","authors":"Katarzyna Piotrowicz,&nbsp;Katarzyna Szyga-Pluta,&nbsp;Alicja Szklarczyk,&nbsp;Ewa Przedpełska-Wąsowicz","doi":"10.1002/joc.70389","DOIUrl":"https://doi.org/10.1002/joc.70389","url":null,"abstract":"<p>Climate change in subarctic regions leads to significant transformations in thermal conditions; however, the long-term variability of the frost-free season (FFS)—and consequently, the growing period—remains poorly documented in Iceland. This study systematically addresses this gap by analysing data from 1951 to 2024. The main objective was to determine the spatial differentiation and long-term trends of FFS. The analysis included the start, end and duration of FFS, as well as the number of days and sums of minimum temperatures below and above 0°C during May–September, based on daily ERA5 reanalysis data (ECMWF/C3S). Trends were calculated using linear regression and their significance assessed with the Mann–Kendall test. Based on six thermal indicators, areas of Iceland characterised by different degrees of change in thermal conditions were identified. Opposing trends in the start (earlier) and end (later) of FFS have led to its systematic lengthening—on average by 5.9 days per decade, with maxima reaching 21.8 days per decade. The highest rates of change were observed in periglacial regions, particularly around Vatnajökull, where the FFS lengthened markedly and frost days (Tmin &lt; 0°C) decreased. Over large glaciers, a distinct type of warming was noted—reflected not in higher Tmin &gt; 0°C, but in rising cumulative Tmin &lt; 0°C values. Spatial classification showed the greatest changes in central Iceland, especially around Vatnajökull, Drangajökull and the Hornstrandir Peninsula, and the smallest in western and coastal regions. The lengthening of the FFS may have significant implications for agriculture, biodiversity and phenology.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.70389","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148269143","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":"Twenty-First Century Projections and Trends of JJAS Rainfall Over the Greater Horn of Africa Under CMIP6 Shared Socioeconomic Pathways Scenarios","authors":"Wogayehu Legese Jima,&nbsp;Gizaw Mengistu Tsidu,&nbsp;Titike Kassa Bahaga","doi":"10.1002/joc.70390","DOIUrl":"https://doi.org/10.1002/joc.70390","url":null,"abstract":"<div>\u0000 \u0000 <p>Understanding future changes in seasonal rainfall over the Greater Horn of Africa (GHA) is critical, given the region's heavy reliance on June–September (JJAS) precipitation for agriculture, water resources and livelihoods. This study examines projected changes in June–September (JJAS) rainfall over the GHA using Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations under three Shared Socioeconomic Pathways (SSP126, SSP245 and SSP585). Projections are derived from CMIP and ScenarioMIP experiments using six top-performing models (CESM2, CESM2-WACCM, EC-Earth3, GFDL-ESM4, HadGEM3-GC31-MM and MPI-ESM1-2-HR), selected based on their skill in reproducing historical JJAS rainfall. Changes are assessed for the near-term (2021–2040), mid-term (2041–2060) and long-term (2081–2100) relative to the 1995–2014 baseline. The analysis focuses on key JJAS rainfall-dependent regions, including the Ethiopian Highlands and western GHA sub-regions and examines both trend behaviour and spatial patterns of projected precipitation change. Results indicate a general tendency toward increased JJAS rainfall across parts of the GHA under the high-emission SSP585 scenario, with half of the models and the multimodel ensemble (MME) showing significant wetting, although projections exhibit pronounced spatial heterogeneity and inter-model variability. In contrast, SSP126 and SSP245 exhibit weak and spatially inconsistent trends, with no uniform regional signal in the MME. Regions that climatologically receive little JJAS rainfall are projected to experience a change in rainfall of up to ~40% across all future periods, although the direction and magnitude of these changes vary among models and emission scenarios. Regional discrepancies among models remain substantial, especially over the Ethiopian Highlands and Sudan region, reflecting the complex influence of large-scale circulation dynamics, regional climate drivers and topographic effects. Projected rainfall changes are dynamically consistent with simulated modifications in subtropical high-pressure systems, low-level moisture transport, upper-tropospheric circulation and tropical sea surface temperature warming. While increased rainfall may enhance water availability in some areas, localized drying and increased variability imply persistent climate risks. These findings highlight a strong scenario dependence of future JJAS rainfall over the GHA and underscore the need for improved regional climate modelling to support adaptation planning, water resource management and climate resilience across the GHA.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148268970","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}