International Journal of Climatology最新文献

{"title":"The Examination of an Improved Analogue Method for Gridded Temperature Variation Reconstruction","authors":"Xuezhen Zhang,&nbsp;Xiaoyue Yan,&nbsp;Maowei Wu,&nbsp;Jingyun Zheng","doi":"10.1002/joc.8755","DOIUrl":"https://doi.org/10.1002/joc.8755","url":null,"abstract":"<div>\u0000 \u0000 <p>The analogue method (AM) is an approach for climate field reconstruction through combining proxy data and modelling data. This study improved the quantitative method of analogue pattern through considering the spatial distribution non-uniformity of proxy data (i.e., <i>k</i>\u0000 _{\u0000 <i>p</i>\u0000} term) and temperature changes capturing ability of proxy data (<i>v</i>\u0000 _{\u0000 <i>p</i>\u0000} term). Meanwhile, this study carries out pseudo-proxy experiments on temperature variations in the eastern Central Asia-East Asia region from 1902 to 1992 to examine the feasibility of the improved AM. The reconstruction results derived from improved AM match well with the instrumental data in terms of the temporal–spatial characteristics of temperature variation, with a correlations coefficient (<i>r</i>) of 0.5 (<i>p</i> &lt; 0.05) for the mean annual temperature (MAT) series, which is higher than that from original AM. The accuracy of the reconstruction results derived from improved AM is primarily depending on the ability of proxy data to capture temperature variations, and is secondly depending on the quantity of available proxy data. In the case of 75 pseudo-proxy maintaining the exactly same distribution with available proxy data but prescribed explaining variances of 100%, 66%, and 33%, there are respectively correlations of <i>r</i> = 0.54, 0.51, and 0.44 (<i>p</i> &lt; 0.05) between reconstructed and instrumental MAT series. When dealing with real proxies, whose explaining variances range from 4% to 24%, the correlation decreases to <i>r</i> = 0.28 (<i>p</i> &lt; 0.05). For a prescribed explaining variance of 100%, corresponding to 75, 37, and 5 proxies, the correlations are <i>r</i> = 0.54, 0.50, and 0.35 (<i>p</i> &lt; 0.05) respectively. These findings demonstrate the potential value of improved AM on the gridded temperature variation reconstruction and highlight the importance of proxy data quality.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749661","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":"Quantifying Multi-Day Precipitation Extremes and Their Linkages With Atmospheric Moisture Flux Over India","authors":"T. H. Gaspar,&nbsp;R. M. Trigo,&nbsp;A. M. Ramos,&nbsp;A. S. Raghuvanshi,&nbsp;A. Russo,&nbsp;P. M. M. Soares,&nbsp;T. M. Ferreira,&nbsp;A. Agarwal","doi":"10.1002/joc.8751","DOIUrl":"https://doi.org/10.1002/joc.8751","url":null,"abstract":"<p>The Indian subcontinent is dominated by a very pronounced summer monsoon season from June to September and a less intense autumn monsoon, both posing major challenges to the densely populated regions, namely through flash floods and landslides. Moreover, the spatial patterns and temporal extent of extreme precipitation events are not uniform across India, with event's durations varying across regions and multiple triggering factors. Here, we make use of a high-resolution daily precipitation dataset covering the entire Indian territory, from 1951 to 2022, to analyse multi-day precipitation extremes and their linkages with regional atmospheric moisture fluxes. We consider 10 sub-regions of India, characterised by different climatic regimes and apply an objective ranking of extreme precipitation events, across various time scales, ranging from 1 to 10 days. Obtained results confirm that the method accurately detects and ranks the most extreme precipitation events in each region, providing information on the daily evolution of the magnitude (and spatial extent affected) of high precipitation values in each region. Moreover, results show that top rank events can be associated with different types of storms affecting the four main coastal regions of India. In particular, some top rank events can be critically linked to long duration events (e.g., 10 days) that can be missed in ranks for shorter duration (e.g., 1–3 days) periods, thus stressing the need to employ multi-day precipitation extremes ranking. Finally, an in-depth analysis of the large-scale atmospheric circulation and moisture transport is presented for the top 10-day events influencing the four coastal regions of India. Results show low pressure systems, which persist over multiple days and play a critical role in linking IVT to MDPEs across the Indian subcontinent. Overall, we are confident that our findings are valuable in advancing disaster risk reduction strategies, optimising water resource management practices, and formulating climate change adaptation strategies specifically tailored for the Indian subcontinent.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8751","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749997","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":"Increasingly Seasonal Jet Stream Raises Risk of Co-Occurring Flooding and Extreme Wind in Great Britain","authors":"John K. Hillier,&nbsp;Hannah C. Bloomfield,&nbsp;Colin Manning,&nbsp;Freya Garry,&nbsp;Len Shaffrey,&nbsp;Paul Bates,&nbsp;Dhirendra Kumar","doi":"10.1002/joc.8763","DOIUrl":"https://doi.org/10.1002/joc.8763","url":null,"abstract":"<p>Insurers and risk managers for critical infrastructure such as transport or power networks typically do not account for flooding and extreme winds happening at the same time in their quantitative risk assessments. We explore this potentially critical underestimation of risk from these co-occurring hazards through studying events using the regional 12 km resolution UK Climate Projections for a 1981–1999 baseline and projections of 2061–2079 (RCP8.5). We create a new wintertime (October–March) set of 3427 wind events to match an existing set of fluvial flow extremes and design innovative multi-event e<i>pisodes</i> (Δ<i>t</i> of 1–180 days long) that reflect how periods of adverse weather affect society (e.g., through damage). We show that the probability of co-occurring wind-flow episodes in Great Britain (GB) is underestimated 2–4 times if events are assumed independent. Significantly, this underestimation is greater both as severity increases and episode length reduces, highlighting the importance of considering risk from closely consecutive storms (Δ<i>t</i> ~ 3 days) and the most severe storms. In the future (2061–2079), joint wind-flow extremes are twice as likely as during 1981–1999. Statistical modelling demonstrates that changes may significantly exceed thermodynamic expectations of higher river flows in a wetter future climate. The largest co-occurrence increases happen in mid-winter (DJF) with changes in the North Atlantic jet stream an important driver; we find the jet is strengthened and squeezed into a southward-shifted latitude window (45°–50° N) giving typical future conditions that match instances of high flows and joint extremes impacting GB today. This strongly implies that the large-scale driving conditions (e.g., jet stream state) for a multi-impact ‘perfect storm’ will vary by country; understanding regional drivers of weather hazards over climate timescales is vital to inform risk mitigation and planning (e.g., diversification and mutual aid across Europe).</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8763","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749998","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":"Controls of Climate and Catchment Behaviour on Runoff Response Across Large-Scale Sample","authors":"Yang Mingjuan,&nbsp;Gong Zhanlong,&nbsp;Pang Tao","doi":"10.1002/joc.8760","DOIUrl":"https://doi.org/10.1002/joc.8760","url":null,"abstract":"<div>\u0000 \u0000 <p>Recent research has extensively examined the response of runoff to climate change. However, the physical mechanisms underlying runoff responses in changing climate conditions remain poorly understood. To address this gap, this study uses measured streamflow and meteorological data from the public GAGES-II database to investigate the physical controls influencing runoff responses to climate and catchment behaviour across more than 1000 catchments in the contiguous United States. Eighteen flow signatures and 56 indicators related to catchment attributes were analysed and grouped using a hierarchical clustering method, resulting in the classification of the 1000+ catchments into ten clusters, each with distinct characteristics. Within each cluster, we explored the patterns of runoff response, focusing on runoff changes and sensitivity for each flow signature and catchment attribute. Our findings indicate that flow signatures such as runoff ratio, annual runoff, and the 95th percentile runoff significantly affect total runoff changes. Evapotranspiration displays a trade-off relationship with overall runoff changes but shows a synergistic relationship with Richard Baker's rapid runoff. Furthermore, the runoff changes driven by catchment attributes align with the total changes, suggesting that catchment behaviour predominantly influences runoff generation processes. Climate factors tend to exert greater influence in arid and semi-arid catchments.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749487","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":"Comparing Surface Mass Balance and Surface Temperatures From Regional Climate Models and Reanalyses to Observations Over the Antarctic Ice Sheet","authors":"Xiaofeng Wang,&nbsp;Peter L. Langen,&nbsp;Rongxing Li,&nbsp;Gang Qiao,&nbsp;Xiaopeng Fan,&nbsp;Yinke Dou,&nbsp;Xiangbin Cui","doi":"10.1002/joc.8767","DOIUrl":"https://doi.org/10.1002/joc.8767","url":null,"abstract":"<p>This article assesses the performance of surface mass balance (SMB) and surface temperature products from seven climate models (ERA5, MERRA2, HIRHAM5_ERA-Interim, HIRHAM5_ERA5, MARv3.11, RACMO2.3p1 and RACMO2.3p2) to be used as inputs to firn densification models (FDMs), crucial for the whole Antarctic mass balance estimation. The evaluation compiles and utilises a new dataset combining existing observations with 184 stake SMB measurements in the Vostok region and two SMB radar transects in Blåskimen Island and Nivlisen Ice Shelf, significantly enhancing the AntSMB dataset. For temperatures at 10 m (T10), 992 observations are included, offering vastly improved spatial coverage. Compared with multi-year SMB observations, RACMO2.3p1 and ERA5 align closely with observed SMB over the inland and the whole Antarctic, with ERA5 exhibiting superior alignment in coastal areas. However, in terms of temporal SMB variations, ERA5, RACMO2.3p2 and HIRHAM5_ERA-Interim demonstrate the best consistency with observed SMB, with ERA5 excelling in regression slope comparisons. In our surface temperature evaluation, RACMO2.3p2 and ERA5 have a minimal mean bias from T10 over the whole Antarctic. RACMO2.3p2 performs well with few occurrences of deviations beyond ±3°C in coastal areas, while RACMO2.3p2 and HIRHAM5_ERA5 are both close to T10 in inland areas. In inter-model SMB comparisons, ERA5, HIRHAM5_Interim, HIRHAM5_ERA5, RACMO2.3p1 and RACMO2.3p2 exhibit similar deviations from the multi-model mean (MMM), while MARv3.11 and MERRA2 show larger deviations in some coastal areas. For surface temperature, MARv3.11 and ERA5 display larger deviations from the MMM in some coastal areas where ERA5 actually matches the observations well, illustrating that MMM should not be taken to represent the true climate conditions. In conclusion, ERA5 demonstrates the best overall consistency with SMB and T10 observations compared with the other models.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8767","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749358","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":"Detection of the Relationship Between the Inverse Variations of Sea Ice in the Okhotsk–Bering Sea During Spring and the 11-Year Solar Cycle","authors":"Shuting Luo,&nbsp;Liang Zhao,&nbsp;Xinyong Shen,&nbsp;Jingsong Wang,&nbsp;Ji Wang,&nbsp;Weiguo Zong","doi":"10.1002/joc.8766","DOIUrl":"https://doi.org/10.1002/joc.8766","url":null,"abstract":"<div>\u0000 \u0000 <p>The 11-year solar cycle is a stable external forcing factor for the Earth system. However, its influence on decadal climate variability, including sea ice, remains uncertain. This study statistically analyses spring sea ice concentration (SIC) and annual sunspot numbers (SSNs) from 1960 to 2021, revealing a significant inverse correlation between the 11-year solar activity cycle and spring sea ice variability in the Okhotsk Sea and Bering Sea. During solar maximum years, sea ice increases in the Okhotsk Sea while decreasing in the eastern Bering Sea. Further analysis shows that the spring sea ice concentration difference (SICD) index correlates closely with the preceding winter Pacific Meridional Mode (PMM) modulated by the 11-year solar cycle. This suggests that solar activity may influence east–west sea ice variability in the North Pacific during spring through its impact on the winter PMM. Atmospheric circulation and numerical simulation results indicate that during high-solar-activity years in winter, changes in stratospheric ozone concentration lead to variations in stratospheric temperatures. This strengthens zonal westerlies in the subtropical stratosphere and troposphere. The propagation of planetary waves from the stratosphere to the mid- and high-latitude troposphere converges over the Bering Sea, creating an easterly anomaly. This convergence stimulates a high pressure and a low pressure to its south, forming a pattern resembling the PMM in the North Pacific during winter. The sea surface temperature (SST) anomalies linked to the winter PMM persist into spring, influencing sea ice at high latitudes in the North Pacific and causing the observed inverse sea ice changes in the Okhotsk and Bering Seas. This study highlights the significant modulating effect of solar activity on sea ice variability, offering insights for understanding Arctic climate change and predicting sea ice changes.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749403","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":"Dynamics of Surface Chlorophyll and the Asymmetric Response of the High Productive Zone in the Peruvian Sea: Effects of El Niño and La Niña","authors":"Dante Espinoza-Morriberón,&nbsp;Rodrigo Mogollón,&nbsp;Oswaldo Velasquez,&nbsp;Guisela Yabar,&nbsp;Manuel Villena,&nbsp;Jorge Tam","doi":"10.1002/joc.8764","DOIUrl":"https://doi.org/10.1002/joc.8764","url":null,"abstract":"<div>\u0000 \u0000 <p>This study analyzes over 26 years of satellite data to explore the seasonal and interannual variability of surface chlorophyll-a from September 1997 to March 2024, focusing on the impacts of the El Niño-Southern Oscillation (ENSO). We investigate how these phases affect the High Productivity Zone (HPZ) during two seasonal periods: The Warm Season (December to April) and the Cold Season (June to September). From an ENSO-neutral perspective, the HPZ is more extensive and exhibits higher chlorophyll concentrations during the Warm Season. Conversely, in the Cold Season, low chlorophyll concentrations are found and the area of the HPZ is reduced by 88,000 km². Under El Niño conditions, chlorophyll-a concentrations decrease consistently along the near-offshore region, but a counter-intuitive increase is observed within the 25 km from shore. La Niña phase enhances chlorophyll in the near-offshore region while reducing it in the very nearshore waters. This study further highlights the asymmetric response of various physical drivers (such as upwelling strength and light) to different ENSO phases. This finding underscores the intricate interplay between ENSO and marine productivity, where the response can vary seasonally. These findings underscore a spatially complex response of the Peruvian coastal productivity to ENSO phases. Understanding these dynamics is vital for predicting future shifts in coastal productivity and for developing adaptive management strategies to mitigate the impacts of climate variability on marine resources.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749786","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":"Characterising Local Flood-Inducing Heavy Rainfall Through Daily Weather Types and Large-Scale Climatic Patterns: Aotearoa New Zealand Study Case","authors":"Andrea Pozo,&nbsp;Matthew Wilson,&nbsp;Marwan Katurji,&nbsp;Laura Cagigal,&nbsp;Fernando J. Méndez,&nbsp;Emily Lane","doi":"10.1002/joc.8762","DOIUrl":"https://doi.org/10.1002/joc.8762","url":null,"abstract":"<p>Flooding is the most frequent natural hazard in Aotearoa New Zealand and the second most costly after earthquakes. It will change in frequency and intensity, becoming more extreme as climate change impacts are realised. The main inundation driver is heavy rainfall. In this study, flood-inducing heavy rainfall is characterised locally by applying synoptic climatological techniques, using the study case of Aotearoa New Zealand. Extending on previous work in the field, a new set of 49 daily weather types (DWTs) is proposed for New Zealand, based on mean sea level pressure (MLSP) and 500 hPa geopotential height (500GH) (predictor variables). The role of the DWTs, the large-scale climatic patterns (LSCPs) known to influence rainfall variability, and the wind conditions (as an additional explanatory variable since they play an essential role in the development of these events) as heavy rainfall and flooding (predictand variables) drivers is investigated using the Wairewa catchment (Little River, Canterbury) as the study site. Heavy rainfall is represented through its temporal and spatial features, based on two rainfall datasets (a rain gauge and a gridded product obtained by the Weather Research and Forecasting (WRF) numerical model). Useful relationships are found between the predictor and the predictand variables. Also, the predictor variables' temporal variability (interannual and intra-annual variability, seasonality) plays a key role, translating to the temporal variability of heavy rainfall and flooding. The proposed synoptic climatological approach provides qualitative and quantitative value, displaying the range of weather and climatic configurations leading to different types of storms and flooding and helping in their identification and understanding.</p>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/joc.8762","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749973","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":"Precipitation Structure and Convective Intensity Over South-East South Asia During Active and Break Spells of the Indian Summer Monsoon Using TRMM, GPM, Megha-Tropiques Satellites and Reanalysis Data","authors":"Shailendra Kumar","doi":"10.1002/joc.8758","DOIUrl":"https://doi.org/10.1002/joc.8758","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, we investigated the precipitation structure (PS) and convective intensity (CI) of precipitation features (PFs) using the multiple sensors onboard on TRMM and GPM for active and break spells (ACT and BRK-Ss) during Indian summer monsoon seasons (1999-2021). Microwave-based observations showed that during ACT-Ss, a higher frequency of PFs is observed over the Himalayan Foothills and northern western Ghats (WGs). Eastern Himalaya Foothills (EHFs), southern India, the Indian Equatorial Ocean, and the Arabian Sea (AS) have a higher frequency of PFs during BRK-Ss. The major differences in PS during ACT and BRK-Ss are observed over WGs and southern-western Himalayan Foothills (S-WHFs). Infrared-based measurements showed that the Bay of Bengal (BOB) and S-WHFs have the deepest Cumulonimbus clouds (minimum brightness temperature) during both ACT and BRK-Ss, but the numbers over BOB are twice as high compared with S-WHFs. S-WHFs have the strongest CI (40 dBZ radar reflectivity has the highest altitude) and precipitation tops (20 dBZ radar reflectivity has the highest altitude) during ACT-Ss. WGs and the Indo-Gangetic Plain (IGP) consist of intense and larger PFs during the BRK-Ss. PFs with the highest horizontal extension, and, which are contributing to higher surface rainfall observed over north-central India and BOB during ACT Ss, but during BRK-Ss, they shifted to EHFs and the Burma-Myanmar coast. Lightning activity is higher at S-WHFs and EHFs during ACT-Ss but shifted at the eastern longitudes of EHFs and southern India during BRK-Ss. Relative humidity (RH) profiles are used to investigate the moist and dry atmospheric conditions during ACT and BRK-Ss. Megha-Tropiques-based sounders showed a higher fraction of RH vertical profiles above mid-troposphere (above 500 hPa) over BOB and S-WHFs during ACT-Ss. WGs and IGP have a higher fraction of RH vertical profiles above the mid-troposphere during BRK-Ss. The balance between RH and vertical velocity is critical in deciding the PS and CI over the selected areas during ACT and BRK-Ss. An updraft with higher RH is observed over BOB, IGP, Central-India, and S-WHF during ACT-Ss. The opposite characteristics are observed over WGs, and a higher RH with a higher updraft is observed during BRK-Ss. The RH-vertical velocity joint histogram shows a broad spectrum width during ACT-Ss compared with BRK-Ss. It shows that even the lower RH can be lifted at higher altitudes due to updraft during the ACT-Ss compared with BRK-Ss. A separate analysis of TRMM and GPM shows that in the last decade, there has been an increase in the deep convective systems during the BRK-Ss, especially over the WGs and Southern India, the Tropical Ocean, and must be investigated in the future.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749971","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 Leading Circulation Patterns of Meiyu Onset in the Yangtze–Huaihe River Valley and Its Relationship With the North Atlantic Sea Surface Temperature Anomalies","authors":"Haoran Yin,&nbsp;Suxiang Yao,&nbsp;Tianle Sun","doi":"10.1002/joc.8769","DOIUrl":"https://doi.org/10.1002/joc.8769","url":null,"abstract":"<div>\u0000 \u0000 <p>The Meiyu rainfall anomaly is closely associated with the early or late onset of Meiyu, and accurately predicting its onset is crucial for disaster prevention and mitigation. This study examines the diverse circulation patterns governing the Meiyu onset in the Yangtze–Huaihe River Valley and elucidates its underlying mechanism through statistical diagnosis and numerical simulation. The findings indicate that over the recent 31 years, three distinct circulation patterns of the Meiyu onset (referred to as MO-I, MO-II and MO-III) with different blocking situations in mid-high latitude are observed. The Rossby wave trains connect the weather systems in the mid-high latitude and subtropical regions, leading to the coevolution of the Western Pacific Subtropical High (WPSH), the South Asian High (SAH), the East Asian Subtropical Westerly Jet (EASWJ) and the Ural blocking pattern. Furtherly, the sea surface temperature (SST) anomalies in the North Atlantic prior to the Meiyu onset can stimulate the key Rossby wave trains that pass through the Ural Mountains and connect with the East Asian subtropical zone. In MO-I, a dipole SST pattern characterised by positive anomalies in southeast Greenland and negative anomalies in the mid-latitude West Atlantic induces negative geopotential anomalies over the Ural Mountains. Concurrently, the WPSH and the SAH exhibit weakened intensities compared to their climatological states, resulting in a delayed onset date relative to the other two types. Conversely, SST anomalies of MO-III exhibit an opposite pattern to MO-I, and the concurrent intensified Ural Blocking High, WPSH and SAH facilitate the earliest Meiyu onset. For MO-II, an antiphase distribution of SST anomalies in the mid-latitude West Atlantic and southern Iceland stimulates two wave trains along the polar front jet and the EASWJ, producing a circulation similar to the climatological state of the Meiyu onset. This research can serve as a foundation for Meiyu prediction and monitoring.</p>\u0000 </div>","PeriodicalId":13779,"journal":{"name":"International Journal of Climatology","volume":"45 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749890","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}