International Journal of Climatology最新文献

{"title":"Changes in Wind Regimes Over Jammu and Kashmir and Ladakh Regions: A Climate Change Perspective","authors":"Saurabh Verma,&nbsp;Charu Singh","doi":"10.1002/joc.70034","DOIUrl":"https://doi.org/10.1002/joc.70034","url":null,"abstract":"<div>\u0000 \u0000 <p>We have examined the changes in surface wind speed patterns during two epochs (F21: 1979–1999- and L21: 2000–2020) to assess wind variability across time, aiming to enhance our understanding of shifts in wind energy potential across Jammu and Kashmir (J&amp;K) and Ladakh. Based on statistically robust Chi-square and K-S tests, it is noted that wind speeds at 10 and 100 m above ground level (AGL) have changed significantly during L21. Results indicate that the change in land use and land cover (LULC) may have impacted the trend of surface wind speed in association with 2 m temperature. The conversion of crop and forest land to woody savannas and further savannas and barren land to permanent snow and ice has decreased surface roughness and enhanced wind speed. The frequency distribution indicates a decrease in 10 m wind speed at a lower magnitude over all the locations, but an increase over Kargil is noted. Daily variation of wind speed at 10 and 100 m AGL revealed a significant increasing trend during daytime. Spatial differences between F21 and L21 have demonstrated that wind speed has increased by 0.2 (0.15) m s⁻¹ at 10 m and 0.5 (0.25) m s⁻¹ at 100 m during winter (summer) months, along with surface temperature over south-eastern Ladakh. By examining the monthly distribution of wind power density at specific locations, we identified that Daulat Beg Oldi, Rhongo and Chushul are the areas with notable wind energy power potential. The monthly variation suggests that winter months are more favourable for wind energy harvesting than summer months.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145228068","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":"Rainfall Variability in South America Modulated by the Central and Eastern Atlantic Niña Modes","authors":"Mary T. Kayano,&nbsp;Rita V. Andreoli,&nbsp;Leonardo Mamani,&nbsp;Wilmar L. Cerón,&nbsp;Itamara Parente Souza,&nbsp;Wallace Cevalho,&nbsp;Rodrigo A. F. Souza,&nbsp;Djanir Sales Moraes","doi":"10.1002/joc.70023","DOIUrl":"https://doi.org/10.1002/joc.70023","url":null,"abstract":"<div>\u0000 \u0000 <p>The present analysis examines the effects of the central Atlantic Niña (NCAN) and eastern Atlantic Niña (NEAN) modes on seasonal precipitation in South America (SA) and related atmospheric circulation during the 1951–2020 period. NCAN is the negative pole of broader Atlantic sea surface temperature (SST) modes: negative South Atlantic dipole (SAD) in all seasons, positive interhemispheric SST gradient (GRAD) in austral summer and autumn, and a weaker positive GRAD in winter. These modes modify the regional Hadley, intensifying the South American low-level jet in autumn, winter and spring. In all seasons, the NCAN mode modifies the regional Walker cell by positioning its descending branch in the central equatorial Atlantic. This branch may extend westward due to the coupling of the negative SST and positive pressure anomalies in the NCAN area (summer and spring) or the anomalous surface warming in the eastern tropical Pacific (winter). Precipitation anomalies feature a dipole between northern (positive values) and northeastern (negative values) SA in summer and autumn and in the other seasons, negative values in northern SA and localised positive values south of 20° S in winter and in the 10° S–25° S band in spring. The NEAN modes have limited influence on the regional atmospheric circulation during summer and spring. But during autumn (winter), the regional anomalous Walker and Hadley cells associated with a negative (positive) GRAD mode and a negative SAD mode modulate the precipitation variability through wind changes. The GRAD mode with reversed polarity from autumn to winter explains the near-reversed dipole precipitation anomaly patterns in tropical SA. The smallest (largest) differences in the seasonal precipitation anomalies between the NCAN and NEAN occur in winter (autumn). Since previous works did not distinguish the longitudinal position of the maximum SST anomalies, the present findings could be relevant for climate monitoring and modelling efforts.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145228067","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":"State of the UK Climate in 2024","authors":"Mike Kendon,&nbsp;Amy Doherty,&nbsp;Dan Hollis,&nbsp;Emily Carlisle,&nbsp;Stephen Packman,&nbsp;Svetlana Jevrejeva,&nbsp;Andrew Matthews,&nbsp;Joanne Williams,&nbsp;Judith Garforth,&nbsp;Tim Sparks","doi":"10.1002/joc.70010","DOIUrl":"10.1002/joc.70010","url":null,"abstract":"<p>This report provides a summary of the state of the UK's climate in 2024. It is one of a series of annual reports published in the <i>International Journal of Climatology</i> (IJC) since 2017. It provides the latest assessment of UK climate trends, variations, and extremes based on the most up to date observations and shows what has already happened to our climate.\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 S1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.70010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144615410","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 Changes in Precipitation and Streamflow in Five Major Peninsular Malaysia River Basins","authors":"Mahmud Shafayet Zamil,&nbsp;Zed Zulkafli,&nbsp;Mohd. Shahrizal Ab Razak,&nbsp;Mou Leong Tan,&nbsp;Zulkifli Yusop","doi":"10.1002/joc.70033","DOIUrl":"https://doi.org/10.1002/joc.70033","url":null,"abstract":"<div>\u0000 \u0000 <p>Despite increasing evidence of the hydrological impacts of climate change, gaps persist in our understanding of the intricate precipitation and streamflow dynamics. Our research investigates the temporal and spatial relationships between precipitation and streamflow for five Malaysian river basins in a 50-year period (1973–2022). Our analysis shows shifts in precipitation time series from 1992 onward and streamflow time series from 1983 onward. The Peninsula's western region experienced significant increases in the annual mean daily precipitation, while positive trends in annual maximum precipitation were identified in only select stations in 3 out of 5 basins. Seasonally, the Perak River Basin demonstrated an evident increase in precipitation during the North-East Monsoon (NEM) that was not reflected in any significant trends in streamflow. Similarly, the Pahang River Basin exhibited positive precipitation trends during both the NEM and Southwest Monsoon (SWM), yet no significant trends were observed in streamflow categories. The Klang River Basin indicated positive precipitation trends in the NEM and SWM that were also reflected in increasing trends in streamflow. Kelantan and Johor River Basins, on the other hand, showed negative trends in streamflow. The trends and shifts in precipitation and streamflow might be ascribed to multiple factors, including regional climate variability, dam operation, mining and land use changes. These findings are of considerable significance in enhancing our understanding of the hydrometeorological dynamics in the region.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145228064","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 Subtropical and Arctic Influences on the Record-Breaking Early Summer Rainfall Over North China in 2022","authors":"Xingxing Li,&nbsp;Jianqi Sun,&nbsp;Shui Yu,&nbsp;Zixuan Zeng","doi":"10.1002/joc.70029","DOIUrl":"https://doi.org/10.1002/joc.70029","url":null,"abstract":"<div>\u0000 \u0000 <p>In June–July 2022, North China experienced unprecedented rainfall in the last 75 years, resulting in flood disasters and economic damage. This study examines the related influence factors and physical mechanisms driving North China's anomalous precipitation in June–July 2022. Results show that the simultaneous diabatic heating over northwestern India associated with the local record-breaking precipitation induces an upper-level anticyclonic anomaly over Northeast Asia via exciting the circumglobal teleconnection pattern, which favours intensified upward motion and more precipitation over North China. In addition, the extreme Arctic warming, especially in the Barents-Kara Sea, in June–July 2022 excites a southeastward-propagated Rossby wave train, leading to low-level cyclonic and upper-level anticyclonic anomalies over the Lake Baikal–Ural Mountains regions and Northeast Asia respectively. The anticyclonic (cyclonic) anomalies drive the local divergence anomalies (southerly wind) in the upper (lower) troposphere of North China, favouring more precipitation over there. The numerical simulation based on a linear baroclinic model could reproduce the above-mentioned physical processes.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145228224","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":"Interdecadal Change of the Interannual Relationship Between Autumn North Atlantic Horseshoe Sea Surface Temperature Anomaly Pattern and Winter Temperature Over Northeast China","authors":"Yuchen Shao,&nbsp;Zhongxian Li,&nbsp;Botao Zhou,&nbsp;Yuanyuan Jiang","doi":"10.1002/joc.70032","DOIUrl":"https://doi.org/10.1002/joc.70032","url":null,"abstract":"<div>\u0000 \u0000 <p>This study investigates the interdecadal change of the relationship between the interannual variation of autumn sea surface temperature (SST) anomalies in the North Atlantic and winter surface air temperature (SAT) anomalies over Northeast China (NEC) during 1961–2020. The analysis reveals that the first empirical orthogonal function (EOF) mode of autumn North Atlantic SST anomalies is the North Atlantic horseshoe (NAH) pattern. The connection between the autumn NAH SST anomaly pattern and winter SAT anomalies over NEC has experienced an interdecadal shift around 1990. It is weak during 1961–1989 (P1), whereas it is strong during 1990–2020 (P2). Further analysis suggests this change is related to the difference in the persistence of the NAH SST anomaly pattern. During P1, the NAH SST anomalies decay rapidly. There are negative–positive–negative geopotential height anomalies around the Western Europe–Ural Mountains–Northeast Asia, resulting in negative SAT anomalies over NEC. In contrast, during P2, the SST anomalies maintain from autumn to winter. The North Atlantic SST anomalies during P2 exert positive–negative–positive geopotential height anomalies around the Davis Strait–Ural Mountains–Northeast Asia, leading to significantly positive SAT anomalies over NEC. The NCAR CAM5.3 simulation results indicate differences in atmospheric circulation over Eurasia, especially Northeast Asia, under different SST forcings during the two periods. The simulation results are basically consistent with the observations.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227989","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":"Evaluation of Machine Learning Models to Improve Daily Precipitation Estimations From Orbital Remote Sensing and Reanalysis Data","authors":"Emerson da Silva Freitas,&nbsp;Victor Hugo Rabelo Coelho,&nbsp;Guillaume Francis Bertrand,&nbsp;Filipe Carvalho Lemos,&nbsp;Cristiano das Neves Almeida","doi":"10.1002/joc.70036","DOIUrl":"https://doi.org/10.1002/joc.70036","url":null,"abstract":"<p>This study focuses on the evolution of the monthly IMERG (Integrated Multi-satellitE Retrievals for GPM) BraMaL (Brazilian Machine Learning) product, the so-called IMERG BraMaL-M, to produce accurate daily precipitation estimations in Brazil (IMERG BraMaL-D) without dependence on ground-based local or regional data. IMERG BraMaL-D uses the satellite-based precipitation product IMERG Early Run and 53 re-analysis variables from MERRA-2 (Global Modelling and Assimilation Office) as inputs for calibration. To achieve the main goal, we evaluated the performance of single (SML), double (DML) and multiple (MML) machine learning methods, using combinations of 6 regression and 8 classification models. The evaluation showed that the K-nearest neighbours (KNN) and the random forest (RF) were the best regression and classification models, respectively. The MML method, combining 5 regression models, was chosen to produce the IMERG BraMaL-D product because it performed statistically better when compared with the observed data from 3227 rain gauges. Compared with the original calibrated product of IMERG (i.e., the Final Run) and three other global satellite-based precipitation products (i.e., PERSIANN-CDR, MSWEP and CHIRPS), IMERG BraMaL-D statistically presented a better performance for almost all analyses. For instance, IMERG BraMaL-D exhibited a KGE (Kling-Gupta Efficiency) of 0.70 for daily estimations, against values ranging from 0.05 (PERSSIANN-DCR) to 0.66 (IMERG Final Run) for the other analysed global products. The monthly accumulated estimations of IMERG BraMaL-D also presented better performance, with smaller data dispersion and KGE rising from 0.86 to 0.95 when compared with IMERG BraMaL-M. Like IMERG BraMaL-M, the main advantages of the IMERG BraMaL-D product are the non-dependency on ground-based datasets after the model's calibration, the improvement of precipitation estimations where the satellite-based products usually underestimate the rain gauge data, and the faster availability to the end-users.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://rmets.onlinelibrary.wiley.com/doi/epdf/10.1002/joc.70036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227988","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":"Summer Thermal Comfort Zoning Studies of Mainland China Based on the Comprehensive Heat Index","authors":"Yingfeng Guo,&nbsp;Zhifeng Wu,&nbsp;Zihao Zheng,&nbsp;Xiaojun Huang,&nbsp;Zhongwen Hu","doi":"10.1002/joc.70035","DOIUrl":"https://doi.org/10.1002/joc.70035","url":null,"abstract":"<div>\u0000 \u0000 <p>With global warming, a better understanding of the summer thermal environment is crucial. Distinct from land surface temperature, which is the most widely noticed and employed parameter of the summer thermal environment, we constructed the Summer Comprehensive Heat Index using six common heat indices (outdoor apparent temperature, heat index, Humidex, modified discomfort index, net effective temperature, and simplified wet-bulb global temperature) through principal component analysis, analysing its spatial distribution and temporal trends (2003–2020) at 10 km grid and county scales across mainland China. Employing Automatic Regionalisation with Initial Seed Location, Regionalisation with Dynamically Constrained Agglomerative Clustering and Partitioning, and Spatial Kluster Analysis by Tree Edge Removal regionalisation methods with spatially constrained and classical statistical approaches, a two-tier geographical division of summer thermal comfort zones was conducted. Results indicate severe thermal stress in Southern China and the Bohai Rim regions, while regions such as the marginal region of the Tibetan Plateau, Inner Mongolia Plateau, and Yungui Plateau offer high thermal comfort, suitable for ‘sunbird’ tourism. Conversely, the Bohai Rim and lower Yangtze regions exhibit extreme heat stress with intensifying warming trends, calling for urgent adaptation. The study highlights regional thermal heterogeneity, providing insights for localised tourism planning and climate resilience strategies.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227991","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 Framework for Quantifying the Robustness and Uncertainty of Drought Projections","authors":"Shaobo Zhang,&nbsp;Zuhao Zhou,&nbsp;Yuqing Zhang,&nbsp;Peiyi Peng,&nbsp;Chongyu Xu","doi":"10.1002/joc.70019","DOIUrl":"https://doi.org/10.1002/joc.70019","url":null,"abstract":"<div>\u0000 \u0000 <p>Drought may be exacerbated by global warming, but drought projections are largely inconsistent. The existing frameworks cannot adequately quantify the robustness and uncertainty of drought projections. Therefore, this study proposes a framework to solve this problem and verifies it in the Chinese Mainland. This framework consists of three main components: (1) the meteorological drought in the 21st century is projected using an impact propagation modelling chain; (2) the robustness of drought projections is quantified using Identical Trend Percentage (ITP) and Signal-to-Noise Ratio (SNR); (3) the uncertainty of drought projections is investigated using improved multi-way analysis of variance. The study reveals that this framework can include more uncertainty sources, investigate the propagation patterns of uncertainty components and quantify the robustness of drought projections. The results show that drought projections are not robust. Specifically, the mean ITP ranges from 49% to 69%, indicating that nearly half of the projections display trends opposite to those of the mean values. In addition, the mean SNR of drought projections ranges between −0.36 and 0.15, with an absolute value far from 1.0. The dominant uncertainty source is the choice of drought index, of which the mean relative contribution ranges between 47% and 61%. When propagating along with the impact propagation modelling chain, the relative importance among existing uncertainty sources usually remains stable if no new physical quantities are joining in. If the relative importance among the existing uncertainty sources for one particular quantity is different from that for the other quantity, the relative importance among the existing uncertainty sources may be adjusted when the two quantities are pooled together by the newly joined processes. Excluding unreasonable drought indices generally reduces the uncertainty and improves the robustness of drought projections; however, it is insufficient to derive robust drought projections.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227990","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":"Peak Date of Precipitation Dominates Peak Greenness Timing of Temperate Grassland","authors":"Wenrui Bai,&nbsp;Huanjiong Wang,&nbsp;Quansheng Ge","doi":"10.1002/joc.70027","DOIUrl":"https://doi.org/10.1002/joc.70027","url":null,"abstract":"<div>\u0000 \u0000 <p>Peak greenness timing (PGT), indicating the timings of seasonal peak canopy structure, plays a key role in the terrestrial ecosystem carbon cycle. We assumed that the peak dates of climatic factors would have a greater impact on PGT than preseason climates because the potential maximum gross primary productivity would only be achieved when PGT matches seasonal peak resource availability. To test this hypothesis, we selected the Mongolian grassland as the study area and extracted the PGT using the MODIS EVI dataset. We simultaneously identified the peak dates of temperature, precipitation and radiation from the ERA5-land dataset. Subsequently, we compared the performance of two multiple linear regression models with peak dates of climatic factors or preseason climates as independent variables to simulate PGT. Finally, we compared the standardised regression coefficients of independent variables for each pixel to identify the dominant factor of PGT in different regions. The results showed that the regression model based on peak dates of climatic factors could explain more interannual variance of PGT in 71.0% of the study area than the model based on preseason climates. Although the dominant factor controlling PGT varied across regions with different background climates, the peak date of precipitation (PDP) was identified as the dominant factor in nearly half of the study area, followed by temperature and radiation. The explanatory power of PDP on PGT was stronger in more arid regions. Our research provides new insights into the drivers of PGT in temperate grasslands and enhances our understanding of how plant phenology adapts to seasonal climate variations.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227976","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}