International Journal of Climatology最新文献

{"title":"Forced Response in the Mean State and Interannual Variability of the Indian Summer Monsoon in Future Projections","authors":"K. Nithya,&nbsp;S. Aneesh,&nbsp;S. Sijikumar","doi":"10.1002/joc.70449","DOIUrl":"https://doi.org/10.1002/joc.70449","url":null,"abstract":"<div>\u0000 \u0000 <p>The Indian summer monsoon (ISM) is a complex system that plays a crucial role in the climate of South Asia. The Community Earth System Model 2-Large Ensemble (CESM2-LE) simulations are used to explore the forced response in the mean state and interannual variability of the ISM in future projections. Simulations during historical periods (1980–2009) show that the model could fairly reproduce the mean state and interannual variability of the ISM in terms of excess and deficient rainfall years and its association with strengthening and weakening of monsoon circulation. It is noticed that though the low-level monsoon jet shows a weakening during deficient monsoon years, it has more eastward extension, up to the western Pacific Ocean, compared to excess monsoon years. In simulations for future periods, the rainfall pattern shows an overall enhancement in the near future (2030–2059) and far future (2070–2099) periods. However, both the low-level jet and tropical easterly jet stream are weaker in future periods than that of the historical period. The future projections also exhibit stronger interannual variability, with wetter excess rainfall years and drier deficient years than corresponding historical years. Moreover, the likelihood of deficient years occurring in the future periods may increase with more dry conditions over southern peninsular India. Since the hundred ensemble mean suppresses most of the natural variabilities, changes that exist in the projected mean values are mainly due to the induced forcing (SSP3-7.0) in the model. The difference between with and without ENSO cases in the interannual variability shows that ENSO amplifies the variability in future projections, particularly in deficient rainfall years. Thus, the results obtained from the CESM2-LE simulations are crucial for developing more effective strategies for managing and policy-making efforts aimed at mitigating the impacts of monsoon variability in a warming world.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862216","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":"A Revisit of the Relative Niño3.4 Index","authors":"Wei Tan,&nbsp;Zeng-Zhen Hu,&nbsp;Yunyun Liu,&nbsp;Nathaniel C. Johnson","doi":"10.1002/joc.70468","DOIUrl":"https://doi.org/10.1002/joc.70468","url":null,"abstract":"<div>\u0000 \u0000 <p>The status of the El Niño–Southern Oscillation (ENSO), the primary source of seasonal climate predictability, is often represented by an index that measures sea surface temperature anomaly (SSTA) in the east-central tropical Pacific, known as the Niño3.4 index. To better isolate ENSO timescale variations and physics, a relative Niño3.4 (rNiño3.4) index has been proposed as the Niño3.4 index departure from the global tropical mean SSTA. However, due to this subtraction, the rNiño3.4 index requires a potentially cumbersome variance adjustment to maintain consistent thresholds for defining ENSO events. Moreover, because the tropical mean SSTA is partially linked to ENSO, we could argue that the ENSO-related component of the tropical mean SSTA should not be removed when defining the rNiño3.4 index. Here, we propose a “revised rNiño3.4” (rrNiño3.4) index, defined as the Niño3.4 index departure from the ENSO-unrelated global tropical mean SSTA. An advantage of the rrNiño3.4 index is that it does not require variance adjustment, making it a physically rational alternative to the ENSO index. The connections to global precipitation and to equatorial Pacific recharge/discharge processes are generally comparable across the Niño3.4, rNiño3.4, and rrNiño3.4 indices. Furthermore, the cooling trends in the rNiño3.4 and rrNiño3.4 indices since 2010 are in line with the enlarged zonal SSTA gradients across the tropical Pacific and a La Niña-like pattern. Thus, from this perspective, both the rNiño3.4 and rrNiño3.4 indices reflect the coupled anomalies between the tropical Pacific atmosphere and ocean on the seasonal-to-interannual and interdecadal timescales.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862441","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":"Subseasonal Predictability of Weekly Rainfall and Rainy Season Onset Over East Africa","authors":"Emmah Mwangi,&nbsp;Gibbon Innocent T. Masukwedza,&nbsp;Dominic Kniveton,&nbsp;Martin C. Todd","doi":"10.1002/joc.70460","DOIUrl":"https://doi.org/10.1002/joc.70460","url":null,"abstract":"<p>Forecasts on subseasonal (SS) timescales have become increasingly vital in bridging the gap between medium-range weather and long-range seasonal forecasts. The East African region is a ‘sweetspot’ for SS predictability, offering strong potential for these forecasts to inform critical agricultural decisions, such as determining the optimal planting times based on the onset of the rainy season. However, knowledge of rainy season onset predictability at this timescale is currently limited. In this paper, we evaluate the predictability of weekly rainfall and rainy season onset over East Africa (EA) at SS timescales in the ECMWF extended range forecast model. The results show that weekly rainfall forecasts have strong predictive skill up to 4 weeks ahead, with the ‘long rains’ March–May (MAM) season having higher skill than the ‘short rains’ October–December (OND). The latest ECMWF model cycle (C48) shows improvements in skill over the previous versions. Subsetting SS weekly forecasts by MJO phases does not produce markedly different results, suggesting that other drivers play a stronger role in shaping SS predictability. SS forecasts of onset dates have notable skill at 2–3 weeks' lead time, with high correlation and ‘hit rates’ (HRs) for forecasts of anomalously early and late-onset years. However, mean absolute errors in onset date forecasts remain high, typically ~6–12 days. This underscores the challenges of predicting specific onset dates and the need for less stringent metrics, such as broader onset ‘windows’. Broader onset windows improve forecast accuracy, though a ±3-day window achieves HRs &lt; 0.5. Analysis of case study seasons of anomalous onset illustrates the operational value of SS onset forecasts in informing agricultural decisions. The study highlights the potential of integrating SS forecasts into a seamless seasonal-to-subseasonal (S2S) framework to support agricultural decision-making and resilience through a ‘Ready-Set-Go’ system. It also reinforces the need to enhance co-production with agricultural stakeholders in determining and evaluating appropriate onset metrics for actionable information to take advantage of the high SS predictability.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.70460","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862476","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":"Spatial and Temporal Variability of Extreme Precipitation Events in the Northwestern Himalayan Region: A Comprehensive Analysis of Trends and Extremes","authors":"Anurag Satpathi,&nbsp; Abhilash,&nbsp;Sameera Qayoom,&nbsp;Neha Chand,&nbsp;Chinmaya Kumar Sahu,&nbsp;Latief Ahmad,&nbsp;Billel Touati,&nbsp;Ali Salem,&nbsp;Mohamed A. Mattar","doi":"10.1002/joc.70461","DOIUrl":"https://doi.org/10.1002/joc.70461","url":null,"abstract":"<div>\u0000 \u0000 <p>Understanding the spatial and temporal dynamics of extreme precipitation is critical for assessing hydroclimatic risks in mountainous regions. This study investigates long-term trends and variability of extreme precipitation across the northwestern Himalayas, encompassing Jammu &amp; Kashmir and Ladakh, using high-resolution CHIRPS data validated against station observations and a suite of ETCCDI (Expert Team on Climate Change Detection and Indices). The results reveal a pronounced hydroclimatic contrast between the two regions. Jammu &amp; Kashmir, particularly the Kashmir Valley and Pir Panjal range, exhibits increasing seasonal and annual precipitation along with a significant rise in rainy days, indicating a shift toward more frequent moderate-intensity rainfall. In contrast, Ladakh shows predominantly neutral to declining precipitation trends, accompanied by a marked increase in consecutive dry days and a declining contribution of extreme precipitation events, reflecting intensifying aridity. Extreme precipitation indices (Rx1day, Rx5day, R95pTOT, R99pTOT) display largely decreasing or spatially inconsistent trends across the region, suggesting a transition toward a precipitation regime dominated by frequency rather than intensity. These findings highlight growing hydroclimatic divergence, underscoring the need for enhanced flood preparedness in wetter regions and strengthened water conservation strategies in arid high-altitude areas.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862207","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":"Winter Extreme Precipitation Over the Western Tibetan Plateau: Circulation Patterns and Underlying Mechanisms","authors":"Zhexing Tan,&nbsp;Ji Ma,&nbsp;Huixin Li,&nbsp;Zhongshi Zhang,&nbsp;Yong Liu","doi":"10.1002/joc.70466","DOIUrl":"https://doi.org/10.1002/joc.70466","url":null,"abstract":"<div>\u0000 \u0000 <p>Winter precipitation over the western Tibetan Plateau (TP) is critical for water security and agriculture in the Indian subcontinent and is largely delivered through extreme events associated with Western disturbances (WDs)—eastward-propagating, synoptic-scale troughs embedded in the subtropical westerly jet. However, the weather regimes conducive to regional extreme precipitation events (REPEs) over this region remain poorly understood. In this study, we use a self-organising map (SOM) to categorise the weather regimes associated with REPEs into three types. The first regime is characterised by a southwest–northeast cyclone–anticyclone dipole, which favours increased precipitation over both the Pamir Plateau and the southern Himalayan slopes. The second regime features a dominant anticyclone over the TP, producing a zonally extended precipitation belt from northern Pakistan to the Hindu Kush. The third regime is associated with intensified cyclonic circulation to the west of the TP, leading to intense precipitation along the southern Himalayas. Moreover, all REPEs are accompanied by at least one WD; however, the genesis and trajectories of WDs vary across regimes, governed by wave energy propagation and subtropical jet variations linked to the evolution of precursor circulations. Further analysis indicates that REPEs over the western TP are closely related to ENSO, the MJO and the NAO. Although these teleconnection patterns operate across multiple time scales and can modulate WD dynamics and moisture supply, none exerts dominant control over any single weather regime. Our study provides new insights into the mechanisms driving extreme precipitation and holds potential for improving the forecasting of REPEs over the western TP.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862208","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":"Research on Cloud Water Resources in the Bayinbuluke Alpine Basin: Climatic Characteristics and Development Potential","authors":"Miao Cai,&nbsp;Junjie Zhao,&nbsp;Jianjun Ou,&nbsp;Jie Yu,&nbsp;Gang Li,&nbsp;YuQuan Zhou","doi":"10.1002/joc.70445","DOIUrl":"https://doi.org/10.1002/joc.70445","url":null,"abstract":"<div>\u0000 \u0000 <p>Under the context of global climate change exacerbating water resource crises in arid and semi-arid mountainous regions, the scientific assessment and development of cloud water resources (CWR) are of great significance for regional water security and ecological safety. Based on a high-resolution CWR diagnostic dataset of China from 2000 to 2024, this study quantitatively evaluates the spatiotemporal distribution and development potential of CWR in the Bayinbuluke alpine basin (BAB)—a typical arid zone in Central Asia. The main findings are as follows: (1) Over the past 25 years, the average annual total hydrometeor mass (cloud water) in this region were about 56.89 billion tons (equivalent to a water depth of ~86.4 mm per unit area), of which about 17.32 billion tons (~239.5 mm) formed surface precipitation. The precipitation efficiency of hydrometeors was about 30.5%, with a slow renewal cycle of ~10.8 h; (2) The average annual aerial CWR (i.e., total hydrometeors minus precipitation) in the mountainous area was about 39.56 billion tons, showing significant seasonal variations—most abundant in summer, followed by spring, and least in winter, consistent with the seasonal distribution of precipitation; (3) Considering the demand and technical methods for cloud water resource development, and after excluding days without precipitation and days with heavy precipitation, the developable potential of CWR is estimated to account for 32.8%–50.5% of the total, that is, ~12.98–19.98 billion tons per year (about 179.4–276.2 mm/year). The study recommends implementing regular cold-cloud seeding (rain/snow enhancement) operations from May to October each year to improve the effective utilization of CWR. This research provides a scientific basis for water resource management in the BAB and serves as a reference for CWR development in similar arid and semi-arid regions globally.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862298","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":"A Global Overview of Lightning Near Tall Structures","authors":"Lucía Pini,&nbsp;Daiana M. Baissac,&nbsp;M. Gabriela Nicora,&nbsp;Ehsan Mansouri,&nbsp;Marcos Rubinstein,&nbsp;Farhad Rachidi,&nbsp;Raúl D’Elía","doi":"10.1002/joc.70450","DOIUrl":"https://doi.org/10.1002/joc.70450","url":null,"abstract":"<div>\u0000 \u0000 <p>This study examines lightning activity from 2012 to 2023 around tall structures situated across diverse geographic settings based on data from the World Wide Lightning Location Network (WWLLN), with the aim of providing a global perspective on lightning incidence in their vicinity. Lightning stroke density was calculated within a 2 km radius of each structure and compared with that in a surrounding annular region extending from 2 to 10 km, enabling the identification of potential local enhancements in lightning activity. The results reveal diverse behaviours among the analysed sites. Increased lightning density near the structures is more likely to be observed under a specific combination of factors, primarily high effective heights (greater than 350 m) and low background lightning activity (around 0.6 strokes km⁻² year⁻¹). Under these conditions, local enhancements in lightning density become more evident. Taking advantage of the global coverage of WWLLN data, this study provides a consistent framework for identifying general trends in lightning incidence near tall structures on a worldwide scale.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862350","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":"Behaviours of Extreme Sunshine Duration Events in Eastern China","authors":"Qiuting Wang,&nbsp;Sijia Wu,&nbsp;Zhaoliang Zeng,&nbsp;Manqing Shi,&nbsp;Ming Luo","doi":"10.1002/joc.70459","DOIUrl":"https://doi.org/10.1002/joc.70459","url":null,"abstract":"<div>\u0000 \u0000 <p>Extreme sunshine duration events (ESDEs) are characterized by anomalously long sunshine and intense solar radiation. ESDEs severely threaten ecosystem functions and human health by disrupting photosynthesis and elevating skin cancer risks, but how these events occur and evolve remains largely unclear. Here, we present an investigation of the synoptic behaviours and driving mechanisms of ESDEs by taking eastern China as an example, using a homogenized daily dataset. We identify four ESDE hotspots featured by persistent anticyclonic and high-pressure anomalies, which promote clear, dry, and stable atmospheric conditions. In the Middle Yangtze River valley, ESDEs are associated with a northward extension of the high-pressure system, which strengthens subsidence and suppresses moisture. In the hotspots of Central and North China, a midlatitude wave train linked to a blocking extension of high-pressure ridge from the northwest parts and a high-pressure centre over the Sea of Japan is identified. Meanwhile, Central China is also modulated by persistent near-surface anticyclonic conditions before and during the ESDEs, creating hotter and drier atmospheric columns. In comparison, ESDEs in Northeast China are mainly controlled by the joint influence of the Northeast Asian thermal high and the high-pressure system over Mongolia. Understanding the synoptic behaviours and mechanisms of ESDEs advances our knowledge of such weather hazards to better mitigate their detrimental effects.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862386","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 Reference Evapotranspiration (ETo) Calculation Methods and Quantifying Climate-Driven Change in Irrigation Demand Across Nepal's Terai","authors":"Umesh Kumar Sujakhu,&nbsp;Rajesh Khatakho,&nbsp;Naresh Suwal,&nbsp;Ayush Poudel","doi":"10.1002/joc.70455","DOIUrl":"https://doi.org/10.1002/joc.70455","url":null,"abstract":"<p>Global food security faces growing pressure from population growth and climate change. Improving water productivity requires optimizing irrigation through accurate reference evapotranspiration (ETo) estimates, yet selecting reliable ETo methods remains difficult in data-scarce Nepal. This study evaluates ETo in the Terai region of Nepal using data from 14 meteorological stations over a historical period (1989–2014) using nine empirical and physically based methods. Coupled Model Intercomparison Project Phase 6 (CMIP6) Global Climate Models (GCMs) data for temperature and precipitation under Shared Socioeconomic Pathways (SSP) SSP245 and SSP585 scenarios were used after downscaling and bias correction to develop a multi-model ensemble for near (2027–2051), mid (2052–2076), and far-future (2077–2100) periods. Using these projections, ETo, crop water requirement (CWR), and irrigation water requirements (IWR) were estimated and compared with historical conditions. Among the evaluated models, the Turc (TU) model consistently outperformed the other models, confirming its robustness for ETo estimation. Climate projections indicate increased winter precipitation, particularly under the SSP585 far-future scenario, alongside rising maximum and minimum temperatures across all scenarios, with stronger warming during winter than the monsoon season. The highest ETo occurred from April to June, and overall ETo is projected to increase under both scenarios, with a pronounced rise (40.7%) in January under SSP585, while slight monsoon-season declines (0.2%–2.3%) are projected under SSP245. CWR peaks during July–September, with the highest values observed in July. Notable increases in CWR are projected in July under SSP585 mid- and far-future scenarios and during winter across all scenarios. IWR exhibits strong seasonality, peaking in the monsoon months, with most stations showing moderate annual increases (5%–14%), although some stations experience substantial declines (13%–36%). Overall, the results highlight strong spatial heterogeneity in future irrigation demand, emphasizing the need for region-specific, climate-resilient water management strategies across the Terai.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.70455","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862396","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":"Evolution of Climate Extremes Over the Indian Subcontinent Using a Revised CEI","authors":"Thota Mohan,&nbsp;M. Rajeevan,&nbsp;Smrutishree Lenka,&nbsp;Kondapalli Niranjan Kumar,&nbsp;P. Rohini,&nbsp;O. P. Sreejith","doi":"10.1002/joc.70467","DOIUrl":"https://doi.org/10.1002/joc.70467","url":null,"abstract":"<div>\u0000 \u0000 <p>Employing observed gridded daily rainfall and temperature datasets for 1971–2022, we developed a revised <i>India Climate Extremes Index</i> (<i>IndCEI</i>) to assess long-term variability in climate extremes across the country. The <i>IndCEI</i> modifies the original CEI framework by integrating seven indicators particularly relevant to the Indian climate system: maximum temperature (<i>T</i>\u0000 _max), minimum temperature (<i>T</i>\u0000 _min), consecutive dry days (CDD), heavy precipitation events, the Standardised Precipitation–Evaporation Index (SPEI), Heat Index (HI), and Excess Heat Factor (EHF). Results reveal robust and widespread warming signals over India, with significant increases in <i>T</i>\u0000 _max extremes across all four homogeneous regions. Northwestern India (NWI) emerges as the principal hotspot, exhibiting the strongest positive trends in <i>T</i>\u0000 _max, HI, and EHF—indicative of intensifying heat stress and more frequent heatwaves. South Peninsular India (SPI) also shows marked increases in drought-related extremes (SPEI, CDD). In contrast, Northeast India (NEI) displays heightened short-duration heavy rainfall events alongside increasing drought episodes, signalling greater hydroclimatic variability. East-Central India (ECI), the core monsoon zone, presents weaker or inconsistent trends, likely reflecting the influence of monsoon variability and embedded low-pressure systems. Spatial analyses indicate that both <i>T</i>\u0000 _max and <i>T</i>\u0000 _min extremes have expanded beyond localised pockets, while drought and HI extremes have intensified and spread inland from coastal areas-creating new hotspots in central and eastern India. At the all-India scale, IndCEI exhibits a statistically significant increasing trend (~0.36% of area per decade), driven primarily by rising heat stress and drought indicators. Overall, the findings highlight a growing risk of climate extremes, particularly heat, drought, and rainfall across India. The results underscore pronounced regional contrasts: western and southern India are increasingly dominated by heat-related stress, while Northeastern India faces rainfall-driven extremes. These expanding hotspots of climate stressors call for region-specific adaptation strategies, particularly addressing heat in NWI, drought in SPI, and rainfall variability in NEI.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"46 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862390","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}