International Journal of Climatology最新文献

{"title":"Impact of the CMIP6 Model Resolution on the Future Behaviour of Wind-Driven Wave Climate for the North Indian Ocean","authors":"Athira Krishnan,&nbsp;S. Neetu","doi":"10.1002/joc.8842","DOIUrl":"https://doi.org/10.1002/joc.8842","url":null,"abstract":"<div>\u0000 \u0000 <p>We investigate the past and future variations in wind-driven wave climate over the North Indian Ocean (NIO) region utilising three climate models involved in the High-Resolution Model Intercomparison Project (HighResMIP) within the Coupled Model Intercomparison Project Phase 6 (CMIP6). We analyse the impact of horizontal grid resolution on the accuracy of reproducing past and future changes in wave climate. Wave climate simulated by Global Climate Model (GCM)-forced Wave Watch III (WWIII) simulation outputs from the historical (hist-1950) and future (highres-future) experiments are employed to depict the multi-resolution portrayal of wave climate and to assess any systematic differences arising from resolution enhancements. Compared with ERA5, the GCM with 50 km resolution simulates stronger waves. The pattern of underestimation and overestimation from ERA5 becomes more pronounced in both extent and magnitude as the GCM resolution decreases to 100 km and 250 km. These coarse-resolution models also exhibit deficiencies in representing inter-annual and inter-seasonal variability, particularly in regions impacted by Tropical Cyclones (TCs) such as the Southeastern Bay of Bengal (BoB), Andaman Sea, Southeastern Arabian Sea (AS), offshore of Western India and so forth. This study highlights the critical issue of relying on climate model data without adequately considering their coarse resolutions or inherent biases compared to observational data. In contrast to the historical wave climate, future projections suggest a decrease in 50-year return values (RV50) over the eastern regions and an increase in the western regions of the AS. Specifically, a 1-m rise in RV50 is projected for the Northwestern AS regions. According to the 50 km model simulation, significant changes in annual mean and maximum Significant Wave Height (SWH) and wind speed are observed in the Eastern AS and Southern BoB, where maximum wave heights are projected to decrease. In contrast, increased wave activity is anticipated in the future for the Northwestern AS and Western AS.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315398","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 Changes of Universal Thermal Climate Index (UTCI) Estimated From Weather Stations and Gradient-Boosted Decision Trees Throughout Japan","authors":"Ryoga Hiroki,&nbsp;Alvin C. G. Varquez,&nbsp;Do Ngoc Khanh,&nbsp;Ryza Rynazal,&nbsp;Florent Renard,&nbsp;Lucille Alonso,&nbsp;Manabu Kanda","doi":"10.1002/joc.8843","DOIUrl":"https://doi.org/10.1002/joc.8843","url":null,"abstract":"<p>Evaluating long-term changes in thermal comfort can be useful for considering measures against thermal-related health risks. In this study, spatio-temporal changes in thermal comfort, using the Universal Thermal Climate Index (UTCI), were calculated from observations at 140 weather stations across Japan for the 1980–2020 period. To derive the mean radiant temperature (MRT) values not readily measured at the stations but required in the estimation of UTCI, a machine-learning model (XGBoost) was developed. The model uses the station observations, coarse-resolution radiation data from the ERA-5 reanalyses dataset, and available globe temperature measurements as predictors. The trend of UTCI throughout Japan in summer was found to be significantly positive. Meanwhile, negative trends were found in stations located in northern areas during the winter. This suggests that not only heat stress risks but also cold stress risks should be given careful attention in colder regions. Lastly, a comparison of the estimated UTCI with prefecture-level daily summertime heat-stroke data reveals that the UTCI threshold above which heat-stroke cases rise drastically varies distinctly between warm and cold regions, with the latter having a lower threshold. These findings could contribute to the estimation of risks attributable to climate change and to better planning of climate-change-resilient cities.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8843","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315400","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":"Widespread Multi-Year Droughts in Italy: Identification and Causes of Development","authors":"Salvatore Pascale,&nbsp;Francesco Ragone","doi":"10.1002/joc.8827","DOIUrl":"https://doi.org/10.1002/joc.8827","url":null,"abstract":"<p>Multi-year droughts pose a significant threat to the security of water resources, putting stress on the resilience of hydrological, ecological and socioeconomic systems. Motivated by the recent multi-year drought that affected Southwestern Europe and Italy from 2021 to 2023, here we utilise two indices—the Standardised Precipitation Evapotranspiration Index (SPEI) and the Standardised Precipitation Index (SPI)—to quantify the temporal evolution of the percentage of Italian territory experiencing drought conditions in the period 1901–2023 and to identify Widespread Multi-Year Drought (WMYD) events, defined as multi-year droughts affecting at least 30% of Italy. Seven WMYD events are identified using two different precipitation datasets: 1921–1922, 1942–1944, 1945–1946, 2006–2008, 2011–2013, 2017–2018 and 2021–2023. Correlation analysis between the time series of Italian drought areas and atmospheric circulation indicates that the onset and spread of droughts in Italy are related to specific phases of the winter North Atlantic Oscillation (NAO), the Scandinavian Pattern (SCAND), East Atlantic/Western Russia (EAWR) pattern and the summer East Atlantic (EA) and East Atlantic/Western Russia (EAWR) patterns. Event-based analysis of these drought episodes reveals a variety of atmospheric patterns and combinations of the four teleconnection modes that contribute to persistently dry conditions in Italy during both winter and summer. This study offers new insights into the identification and understanding of the meteorological drivers of Italian WMYD events and serves as a first step toward a better understanding of the impacts of anthropogenic climate change on them.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8827","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315399","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":"Evaluation of Clouds in the Conformal Cubic Atmospheric Model Using the CFMIP Observation Simulator Package","authors":"S. C. H. Truong,&nbsp;M. Thatcher","doi":"10.1002/joc.8846","DOIUrl":"https://doi.org/10.1002/joc.8846","url":null,"abstract":"<p>Cloud amounts and cloud phases reproduced from single-moment (SM) and double-moment (DM) microphysics schemes within Conformal Cubic Atmospheric Model (CCAM) at 105 km resolution are evaluated against CALIPSO-GOCCP and CloudSat observations using the CFMIP Observation Simulator Package (COSP). Both schemes demonstrate skill in reproducing liquid and ice clouds. However, a persistent deficiency in mid- and high-level liquid clouds remains, contributing to an underestimation of total cloud cover, particularly in the tropics. A comparison between the SM and DM schemes highlights two key improvements. First, DM-CCAM exhibits better agreement with observed low-level cloud fractions exceeding 60% in the eastern subtropical oceans. Second, it provides a more accurate representation of ice cloud amounts from 30° toward the poles. Further investigation into the vertical structure of clouds over the Tropical Warm Pool, Southeast Pacific Subtropical Stratocumulus region, and Southern Ocean reveals systematic biases in both CCAM simulations. Notably, the model tends to overproduce optically thick clouds while underrepresenting optically thin clouds in the upper troposphere. Additionally, the model simulates a higher occurrence of drizzle and light rain, along with a lower frequency of non-precipitating clouds in the lower troposphere. Future work will explore the impact of increased horizontal resolution (e.g., 4 km) on cloud characteristics within the CORDEX-Australasia domain, which could provide further insights into model performance and inform refinements.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8846","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315401","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":"Improved Trend Analysis With EOFs and Application to Warming of Polar Regions","authors":"Ewan T. Phillips,&nbsp;Holger Kantz","doi":"10.1002/joc.8823","DOIUrl":"https://doi.org/10.1002/joc.8823","url":null,"abstract":"<p>Given the complexity of climate systems, trends are generally expected to have both global and local features. The use of Empirical Orthogonal Function (EOF) analysis to decompose these different trends has been brought into question. In this paper we show that for land regions of the order of size of most countries the first Principal Component (PC) obtained by EOF analysis in fact captures the entire trend of the time series. We demonstrate a simple linear relation relating the amount of variance described by PCs and the size of the system. We provide a novel normalisation and ordering of the PCs, and show that this provides important insight for larger more complex regions where several PCs are added. We apply this framework along with a recently introduced method to deal with long range correlations to the study of warming trends in the polar regions between 1979 and 2023. We find a significant Arctic warming trend of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mfenced>\u0000 <mrow>\u0000 <mn>0.71</mn>\u0000 <mspace></mspace>\u0000 <mo>±</mo>\u0000 <mspace></mspace>\u0000 <mn>0.26</mn>\u0000 </mrow>\u0000 </mfenced>\u0000 </mrow>\u0000 </semantics></math> K/dec. In the case of Antarctica we find insignificant trends both for West Antarctica and East Antarctica (including ice sheets) of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mfenced>\u0000 <mrow>\u0000 <mn>0.09</mn>\u0000 <mspace></mspace>\u0000 <mo>±</mo>\u0000 <mspace></mspace>\u0000 <mn>0.13</mn>\u0000 </mrow>\u0000 </mfenced>\u0000 </mrow>\u0000 </semantics></math> K/dec. and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mfenced>\u0000 <mrow>\u0000 <mn>0.08</mn>\u0000 <mspace></mspace>\u0000 <mo>±</mo>\u0000 <mspace></mspace>\u0000 <mn>0.17</mn>\u0000 </mrow>\u0000 </mfenced>\u0000 </mrow>\u0000 </semantics></math> K/dec. respectively.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 7","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8823","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256609","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":"A Decadal Decrease in May Precipitation Over Yunnan, China After 2009 and Its Associated Atmospheric Circulation","authors":"Ji Ma,&nbsp;Ruowen Yang,&nbsp;Wen Chen,&nbsp;Peng Hu,&nbsp;Shu Gui,&nbsp;Zizhen Dong,&nbsp;Yuchi Zhang","doi":"10.1002/joc.8847","DOIUrl":"https://doi.org/10.1002/joc.8847","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, the authors identify a decadal decrease in May precipitation over Yunnan, China, after 2009. Based on observed data from meteorological stations, the area-average precipitation in May over Yunnan has decreased from 135 mm during the period 1999–2008 to 83 mm during the period 2009–2019. The decline in precipitation is particularly pronounced in the southwestern and central regions of Yunnan, where it exceeds 100 mm. The moisture budget analysis indicates that the dynamical component of the vertical moisture advection, which is generated by the anomalous descending motion, is the largest contributor to the precipitation decrease after 2009 over Yunnan, followed by the thermodynamic component of the horizontal moisture advection. Further analysis suggests that the regional descending motion and low-level divergence may be attributable to the combined influence of Eurasian wave trains associated with the anomalous North Atlantic SST pattern and warm SST anomalies in the tropical western Indian Ocean (TWIO). On the one hand, the subtropical branch of the Eurasian wave train induces upper-level convergence anomalies over the upper Lancang–Mekong basin, which facilitates the local descending motion and low-level divergent circulation. On the other hand, the Indian Ocean has experienced a remarkable warming around 2009, particularly over the tropical western Indian Ocean. As a result, an anomalous vertical circulation is observed, with ascending motion over the TWIO and descending motion over Yunnan and neighbouring regions. These findings may provide further insight into the dynamic processes behind the observed precipitation decrease and the occurrence of frequent droughts over Yunnan in recent years.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315414","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":"European Climatology of Day-to-Day Surface Air Temperature Difference in Multiple Data Sets","authors":"Radan Huth,&nbsp;Tomáš Krauskopf","doi":"10.1002/joc.8839","DOIUrl":"https://doi.org/10.1002/joc.8839","url":null,"abstract":"<p>Substantial progress has been made in analyses of climate means and extremes, while much less has been done in understanding short-term (intraseasonal and synoptic-scale) variability. One particular aspect of short-term atmospheric variability is day-to-day temperature difference (DTD). Large DTDs negatively affect human health and also impact animals and plants, hence constituting one of the many weather-related risks to society. The main objectives of this study are to provide the climatology of statistical characteristics (distribution width, skewness and kurtosis) of DTD in Europe and compare DTD climatologies between five data sets (station observations, ECA&amp;D; gridded observations, E-OBS; and reanalyses, NCEP/NCAR, JRA-55 and 20CR). DTD is largest in winter and smallest in summer; it tends to grow from the coast towards inland. Skewness is mostly negative in summer, whereas positive skewness prevails in winter with the exception of the British Isles and southeastern Europe. DTD distributions are leptokurtic (i.e., having kurtosis higher than Gaussian), with lower values of kurtosis prevailing in western Europe. Comparisons among data sets reveal their specific deficiencies, such as the existence of outlying unrealistic temperature values in station data that were not detected by quality check, the underestimation of the magnitude of DTD, particularly by the 20CR reanalysis, and overestimated skewness in the British Isles in winter by the reanalyses. The data set differing most from the others is the 20CR reanalysis, which exhibits substantial biases in skewness and kurtosis over large parts of Europe. On the other hand, the reanalysis most consistent with observations is JRA-55.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8839","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315415","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":"The Skill of Extended-Range ERPAS and GloSea5 Models in Capturing Extratropical–Tropical Interactions During the North Indian Summer Monsoon","authors":"Mahesh Kalshetti,&nbsp;Rajib Chattopadhyay,&nbsp;Andrew G. Turner,&nbsp;R. Phani,&nbsp;Susmitha Joseph,&nbsp;A. K. Sahai","doi":"10.1002/joc.8834","DOIUrl":"https://doi.org/10.1002/joc.8834","url":null,"abstract":"<div>\u0000 \u0000 <p>The transient eddies in the atmosphere are short-lived, moving disturbances prominent over mid-latitude. Transient eddy transport enables the exchange of mass, energy, and moisture between extratropical and tropical regions. Based on observations, about 40% of the rain that falls in northern India during the summer monsoons is influenced by transient eddy heat and momentum fluxes. During these rainfall cases, the four-stage cycle of transient eddy heat and a momentum feedback process exists. Global-scale circulation anomalies are generated due to their forcing on the mean flow. This impact of transient eddies on mean flow is referred to as eddy–eddy feedback, commencing in around 22 days. On a daily scale, the enhancement of rainfall over the Western Ghats and north-western India is linked with upper tropospheric poleward transient eddy heat flux transport and equatorward transient eddy momentum flux transport. On a quasi-biweekly scale, however, the transport direction reverses. Additionally, this rainfall pattern is governed by the meridional passage of monsoon intraseasonal oscillation phases (MISO, tropical mode) and the zonal passage of wave number 7–8 patterns (Rossby wave, extratropical mode). Interactions of tropical–extratropical modes are associated with this eddy –eddy feedback that drives the hemispheric upper-tropospheric circulation patterns. This includes wave generation, propagation, and the dissipation of waves away from the source region. The hindcast skill analysis of subseasonal to seasonal scale models, namely Extended Range Prediction Application to Society (ERPAS) and Global Seasonal Forecast version 5 (GloSea5), shows that the models can predict northern Indian rainfall associated with eddy–mean flow interactions at 1-week lead times. After a week, the skill of both models diminishes under the influence of transient eddy transport. The monsoon circulation is more consistent and predictable in both models when transient eddies are absent. A theoretical understanding of the dynamical feedback of upper-tropospheric transient eddies is crucial for improving rainfall prediction.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315413","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 Impact of Tropical Sea Surface Temperature on the Arctic Stratospheric Polar Vortex Trend","authors":"Cuijuan Sui,&nbsp;Alexey Yu Karpechko,&nbsp;Lejiang Yu,&nbsp;Licheng Feng,&nbsp;Shan Liu","doi":"10.1002/joc.8833","DOIUrl":"https://doi.org/10.1002/joc.8833","url":null,"abstract":"<div>\u0000 \u0000 <p>The changes in the Arctic stratospheric polar vortex are influenced by various factors and exert impacts on both the weather and climate of the troposphere and the surface. In this study, we analysed the trends of the stratospheric polar vortex using the self-organising map (SOM) method. There is a decreasing trend in the occurrence of strong polar vortices, while there is an increasing trend in the occurrence of weak polar vortices. The analysis revealed that nine nodes (3 × 3) of SOMs can explain approximately one-third (the trend contribution ratio is 33.4%) of the significant increase in the geopotential height field, in which two nodes (Nodes 3 and 7) amount to approximately three-quarters (25.23%) of the total contribution (33.4%). Significantly positive sea surface temperature (SST) anomalies in the tropical western Pacific and the southwestern Pacific Ocean associated with Node 3 enhanced convective activity in these areas, resulting in negative Rossby wave sources (RWS) and divergent winds, triggering a Rossby wave train. This wave train generates positive geopotential height anomalies over the Arctic Ocean in the stratosphere, which helps weaken the Arctic polar vortex. A wave train excited by suppressed convective activity in the tropical West Pacific and South China Sea related to Node 7 propagates northeastward along a similar path to middle and high latitudes. However, this wave train induces geopotential height anomalies opposite in sign over the Arctic Ocean, which favours the strengthening of the polar vortex. The EP flux in the high-latitude lower stratosphere associated with the two above wave trains can explain the Arctic polar vortex anomalies. Our results show that the influence of SST in the warm pool region on the stratospheric polar vortex is greater than in other ocean regions.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315126","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":"Cruel Summer (and Autumn): Humid Heat Trends, Extremes, and Mechanisms in the Southeast United States","authors":"Shawn M. Milrad,&nbsp;Kelsey E. Ennis,&nbsp;Desiree A. Knight,&nbsp;Kathie D. Dello,&nbsp;Lily Raye,&nbsp;Kyle R. Wodzicki","doi":"10.1002/joc.8837","DOIUrl":"https://doi.org/10.1002/joc.8837","url":null,"abstract":"<div>\u0000 \u0000 <p>Humid heat has increased in frequency, intensity and duration in many locations across the globe, particularly those with warm and moist climates like much of the Southeast United States. This study employs an established wet bulb globe temperature (WBGT) estimation formula and high-resolution reanalysis data to develop a custom gridded WBGT dataset for the Southeast. Subsequently, summer and autumn WBGT (humid heat) trends and extremes are elucidated for 1950–2023. Results complement and correspond well to recent station-based work as well as gridded trends in the Universal Thermal Comfort Index (UTCI). Overall, trends in average and extreme (90th percentile) WBGT are larger and more widely statistically significant at night and during summer. Autumn WBGT increases are largest and most significant in the Florida Peninsula and near the Gulf Coast, where the heat content of the adjacent water peaks in September. Furthermore, there are large increases in the frequency and duration of summer night-time extremes; regions near the Gulf and in Florida are experiencing nearly three additional extreme summer nights per decade, and extreme events are approximately one night longer per decade. A quantification of WBGT components shows that moisture (dewpoint) increases exceed temperature increases and are the largest contributors to WBGT across most of the Southeast, except in parts of the Appalachian and Piedmont regions where temperature changes dominate. Wind speed and solar radiation changes are quite small across the Southeast and are at best minor contributors to WBGT trends. Results support previous literature that moisture changes are most responsible for humid heat trends in warm and moist climates.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 8","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315137","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}