Guhan V , A. Dharma Raju , Rama Krishna , K. Nagaratna
{"title":"Evaluating weather trends and forecasting with machine learning: Insights from maximum temperature, minimum temperature, and rainfall data in India","authors":"Guhan V , A. Dharma Raju , Rama Krishna , K. Nagaratna","doi":"10.1016/j.dynatmoce.2025.101562","DOIUrl":"10.1016/j.dynatmoce.2025.101562","url":null,"abstract":"<div><div>This research presents a comprehensive evaluation of meteorological trends using a combination of statistical and machine learning approaches, focusing on rainfall, minimum temperature (MinT), and maximum temperature (MaxT). The Mann-Kendall trend test and Sen’s slope estimator identified statistically significant upward trends in both MaxT (slope = 0.0154, p = 9.42E-06) and MinT (slope = 0.0190, p = 4.73E-07), indicating a consistent warming climate. Rainfall displayed a positive trend but was not statistically significant (p = 0.9516, slope = 4.07E-05), suggesting random variability rather than a sustained increase.Machine learning models were leveraged to enhance forecasting accuracy for these meteorological parameters. ARIMA exhibited the highest precision for MaxT and Rainfall (MAE = 3.0080, 0.1728; RMSE = 3.4967, 0.2916), while XGBoost demonstrated superior performance for MinT (MAE = 2.7726, RMSE = 3.8555). These findings highlight the critical need for climate adaptation measures, as rising temperatures could intensify heatwaves, escalate energy demands, and affect agricultural productivity.The study underscores the importance of integrating advanced forecasting techniques to support proactive climate resilience planning. By incorporating machine learning models with traditional statistical analyses, this research provides valuable insights into climate trends, aiding policymakers and researchers in formulating effective climate adaptation strategies.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101562"},"PeriodicalIF":1.9,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144146714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"New formulas for estimating initial dilution of buoyancy-dominated jets in a current","authors":"Galip Seckin , Cagatayhan Bekir Ersu , Irfan Macit","doi":"10.1016/j.dynatmoce.2025.101561","DOIUrl":"10.1016/j.dynatmoce.2025.101561","url":null,"abstract":"<div><div>For buoyancy-dominated effluents discharged into moving water, three distinct regions are recognized: the buoyancy-dominated near field (BDNF), the buoyancy-dominated far field (BDFF), and an intermediate transition region. Most existing initial dilution formulas—derived from empirical and field studies—focus on the BDNF and BDFF regions while neglecting the transition zone. In this study, two new semi-empirical equations were developed using field and experimental data: one for submerged discharges and another for minimum surface dilution. These equations were calibrated via nonlinear regression, offering a unified approach to effectively calculating initial dilution across both the BDNF and BDFF regions while also addressing the transition region’s dilution in a single step. The proposed formulas were further validated through comparison with an earlier semi-empirical model using the same dataset.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101561"},"PeriodicalIF":1.9,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144146715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 effects of climate change on the thermal stratification of the Gulf of Oman","authors":"Shirin Farkhani, Nasser Hadjizadeh Zaker","doi":"10.1016/j.dynatmoce.2025.101560","DOIUrl":"10.1016/j.dynatmoce.2025.101560","url":null,"abstract":"<div><div>Water temperature and thermal stratification have fundamental effects on marine environments, ecosystems, and water circulation patterns. Marine ecosystems are generally highly sensitive to thermal changes. Global warming can fundamentally alter oceanic temperature fields and thermal stratification(Cheng, 2019)(Cheng, 2019). Therefore, studying the effects of climate change on the thermal characteristics of the oceans and seas is vital. Using numerical modeling, and three Representative Concentration Pathway (RCP) scenarios, we studied the effects of global warming on the sea surface temperature and vertical thermal structure of the Gulf of Oman. Atmospheric data from the ERA5 and CORDEX models were used for recent past (1980–2000) and future (2080–2100) modeling, respectively. Results indicated that, in the future climate, the temperature across the upper 1000 m of the Gulf of Oman will increase. In summer, temperature increments in the surface mixed layer were estimated at + 1.9, + 2.5, and + 3.4°C for RCP 2.6, 4.5, and 8.5, respectively. Below the thermocline, the temperature increments were less than the ones in the surface mixed layer. In winter, future temperature increments in the surface mixed layer were + 1.2, + 1.6, and + 2°C for RCP 2.6, 4.5, and 8.5, respectively. The results indicated a stronger summer thermocline in the future with temperature gradients of 0.055, 0.057, and 0.06 °C/m in the RCP 2.6, 4.5, and 8.5, respectively, which could significantly reduce dissolved oxygen concentration in the lower layers. This study provides insights that can help develop adaptable strategies to manage and mitigate the harmful impacts of global warming on the Gulf of Oman.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101560"},"PeriodicalIF":1.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Improving significant wave height prediction via temporal data imputation","authors":"Jia Si , Jie Wang , Yingjun Deng","doi":"10.1016/j.dynatmoce.2025.101549","DOIUrl":"10.1016/j.dynatmoce.2025.101549","url":null,"abstract":"<div><div>Accurate prediction of significant wave height (SWH) is crucial for a wide range of marine and coastal applications. However, achieving an accurate data-driven prediction of SWH requires effective multivariate time series modeling. Furthermore, missing values appear frequently in the raw data and influence the accuracy of the prediction. In this study, we propose a novel diffusion-based approach for continuous-time modeling and temporal imputation of multivariate time series. By learning the temporal correlations and interdependencies among variables in the buoy’s data, the imputation of missing data is conducted to enhance the SWH prediction. Experiments are performed using buoy data from the National Data Buoy Center of USA to validate the effectiveness of temporal imputation and the use of multivariate data. The experimental results, compared with baseline methods and univariate predictions, highlight the advantage of Conditional Score-Based Diffusion Models (CSDI) in capturing temporal correlations and its effectiveness in improving short-term predictions of SWH. CSDI improves imputation by 7%–30% over existing imputation methods on popular performance metrics. Compared to univariate data, the better SWH prediction results on multivariate data confirm that temporal data imputation is beneficial for prediction.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101549"},"PeriodicalIF":1.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Formation mechanism of overshooting convection in the southwest vortex circulation under the influence of mesoscale gravity wave","authors":"Yizhou Xu , Guoping Li , Xiaoyu Zhang , Yuanchang Dong , Xin Xie","doi":"10.1016/j.dynatmoce.2025.101559","DOIUrl":"10.1016/j.dynatmoce.2025.101559","url":null,"abstract":"<div><div>Using ERA5 reanalysis data, GPM satellite precipitation products, and radar mosaic combination reflectivity (RMCR) data, the formation mechanism of overshooting convection (OC) in the southwest vortex (SWV) circulation under the influence of mesoscale gravity wave (MGW) on 18 Jul 2022 was analyzed on synoptic dynamics to deepen the understanding of the correlation characteristics between the SWV and the MGW, and then to explore the formation mechanism of OC in the Sichuan Basin (SCB). Results showed that the undulating terrain and stable atmospheric stratification generated the MGW. The adjustment of the SWV circulation caused the strong water vapor flux convergence at 850 hPa in the early stage of OC. The change of divergence field caused by MGW promoted the eastward development of the updraft in the SWV circulation, and the SWV center tilted to the southeast. The ascending center separated by the SWV merged horizontally with the updraft phase of MGW, and the merged ascending airflow connected vertically to the ascending center in the upper troposphere. The water vapor convergence and heating center in the upper troposphere and the horizontal wind momentum transporting upward led to OC. The strengthening of the negative vertical vorticity phase of MGW and the movement of dry cold air mass led to the northwestward propagation of negative vertical vorticity, thus forming the difference in the vertical distribution of vertical vorticity, which was negative in the upper and positive in the lower. The stable updraft phase of the MGW and the dry cold air mass propagation cooled the lower atmosphere and increased the convective available potential energy (CAPE). The adjustment of the internal circulation of the SWV extended the range of convective instability from the ground to 600 hPa, which was also conducive to the formation of OC.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101559"},"PeriodicalIF":1.9,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sergei I. Badulin , Andrey G. Kostianoy , Sergey A. Lebedev , Alexander P. Popov
{"title":"The Caspian Sea as a full-scale experimental facility supported by altimetry measurements of wind-driven waves","authors":"Sergei I. Badulin , Andrey G. Kostianoy , Sergey A. Lebedev , Alexander P. Popov","doi":"10.1016/j.dynatmoce.2025.101554","DOIUrl":"10.1016/j.dynatmoce.2025.101554","url":null,"abstract":"<div><div>The Caspian Sea is the largest inland water body. Strong and stable winds regularly occur along its longest stretch of more than 1000 km from the Volga Lowland in Russia to the Iranian coast. During these events, wind speeds can exceed 20 m/s and significant wave heights 5 m. These wind directions often align with the tracks of satellite altimeters that have been monitoring the sea state since September 1992. This makes the Caspian Sea an ideal location replicating idealized conditions for the growth of wind-driven waves, and supported by a high-precision network of satellite altimeters.</div><div>The shape of the coastline and prevalent wind directions allowed us to view the sea as a full-scale wind-wave research facility. In situ measurements and observations of sea state in this area are scarce and inaccurate while the altimetry tracks provide a ready-to-use high-quality measurement network. We analyze data of satellite missions Jason-3 for years 2016-2022 and CFOSAT (Chinese-French Oceanography SATellite) for 2019-2023 to assess the potential of the full-scale experimental facility. These missions provide valuable data showcasing the Caspian Sea as a realistic model for the World Ocean with minimal contaminating effects of swell, tides and currents. This makes the “clean cases” of the Caspian Sea particularly valuable both as a reference for understanding general wave physics and for regional studies on sea wave dynamics.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101554"},"PeriodicalIF":1.9,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143936014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Monsoon dynamics and future projections in the Himalaya: Insights into sea surface temperature, sea level pressure relationships, and future flood risks","authors":"Mayank Shekhar , Pushpendra Pandey , Shaktiman Singh , Anupam Sharma","doi":"10.1016/j.dynatmoce.2025.101558","DOIUrl":"10.1016/j.dynatmoce.2025.101558","url":null,"abstract":"<div><div>The Himalaya influences the fundamental features of the Indian Summer Monsoon (ISM) circulation across South Asia. Reliable predictions of ISM dynamics require an improved understanding of the relationship with the El Niño–Southern Oscillation (ENSO)–sea surface temperature (SST) and Sea Level Pressure (SLP) relationships in the Niño region. To address this, we conducted a detailed analysis of teleconnections, correlations, regime shifts, periodicity, and return periods of monsoons over the Karakoram Himalaya (KH), Western Himalaya (WH), Central Himalaya (CH), and Eastern Himalaya (EH) using gridded precipitation, ENSO-SST, and SLP data across the Niño 4, 3.4, and 3 regions. Additionally, we examined Coupled Model Intercomparison Project phase 5 (CMIP5) projections considering evolving relationships. The findings show that the monsoons over the CH, WH, EH, and KH have stronger, moderate, weaker, and weakest spatial correlations, respectively, with the SST of Niño regions. Notably, the SST anomalies for the Niño regions 4 and 3.4 reveal distinct regime shift for the years 1977 C.E. and 1990 C.E., however, Niño regions 3 and 1 + 2, do not exhibit any such shift. The SST anomalies for the Niño 3.4 and Niño 4 from 1977 to 2019 C.E., and 1990–2019 C.E., were 0.087°C and 0.060°C, respectively, indicating systematic warming of the sea surface. This warming trend is further linked to projections from CMIP5 RCP 4.5 and RCP 8.5, which suggest that the EH region may experience significant flooding during the monsoon months by 2100 due to high and extreme precipitation.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101558"},"PeriodicalIF":1.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparative drought analysis in Amasya and Merzifon with ZSI, PNI and NDI under transitional climatic conditions","authors":"Utku Zeybekoglu","doi":"10.1016/j.dynatmoce.2025.101556","DOIUrl":"10.1016/j.dynatmoce.2025.101556","url":null,"abstract":"<div><div>Drought is a recurring global problem characterised by multiple climatological and hydrological parameters, causing significant damage to both the natural environment and life. The onset of a drought is characterised by a meteorological drought, which is defined as a decrease in precipitation. The present study investigates the meteorological drought experienced by Amasya and Merzifon, which are located within the transition zone between the Black Sea and continental climates in Türkiye. The drought analysis utilised the ZSI, the PNI and the NDI which is a metric employed to quantify drought. Furthermore, the temporal trends of precipitation, temperature and drought values were investigated using Mann-Kendall, Spearman's Rho and Innovative Trend Analysis. The Drought Indices (DIs) identified significant dry years in 1964–1966, 1974–1975, 1981–1982, 1984, 1986, 1989–1990, 1994, 1999, 2001–2003, 2006–2007, 2011, 2013–2015, and 2017–2021. The assessment revealed that the ZSI, the PNI and NDI performed similarly in terms of identifying drought. The trend analysis results indicate a rising trend in precipitation and temperatures. While ZSI and PNI show an increasing trend, NDI also tends to decrease due to the effect of temperature. The results of both the drought and trend analyses suggest that temperature plays a more influential role in the regional climate compared to other meteorological parameters.The findings reveal the historical development of droughts in the region and their effects on the region's environment with different drought indices. The findings herein have the potential to provide a scientific foundation for the management of local drought conditions. It is posited that by implementing preventative measures and formulating suitable strategies, the likelihood of significant drought-related problems can be substantially mitigated.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101556"},"PeriodicalIF":1.9,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Revisiting the differential impacts of Eastern‐Pacific and Central‐Pacific El Niño on late autumn to winter precipitation over South China","authors":"Lanyu Jia, Yongqing Guo","doi":"10.1016/j.dynatmoce.2025.101557","DOIUrl":"10.1016/j.dynatmoce.2025.101557","url":null,"abstract":"<div><div>Although intensive studies examined the precipitation anomalies in China during the Eastern-Pacific (EP) and Central-Pacific (CP) El Niño, the impact of the CP El Niño event on winter precipitation in South China remains controversial. Besides, precipitation in South China peaks from late autumn to winter (November, December, and January, NDJ) during the winter half-year. These motivate us to revisit NDJ precipitation anomalies in South China during the EP and CP El Niño events. Results show that significantly increased precipitation is observed during both types of El Niño events. However, the spatial patterns and intensities of the precipitation anomalies differ. During the EP El Niño event, large positive precipitation anomalies appear throughout South China. In contrast, during the CP El Niño event, much smaller precipitation anomalies occur primarily in the southwest-to-northeast inland region of South China. These differences originate from the varying locations and intensities of warm sea surface temperature (SST) anomalies in the equatorial Pacific related to El Niño. The SST anomalies during the CP El Niño are located farther west and weaker than during the EP El Niño. A pair of an anomalous anticyclone east of or over the Philippine Islands and an anomalous cyclone northeast of South China connect these SST anomalies to precipitation in South China. We demonstrate that the correlations between CP El Niño and NDJ precipitation anomalies in South China vary remarkably across different periods. This may explain the source of controversy regarding the impact of the CP El Niño on precipitation in South China.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101557"},"PeriodicalIF":1.9,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sea surface temperature and marine heatwave variability in interconnected basins: The Black-Marmara-Aegean Seas","authors":"Şehriban Saçu , Olgay Şen , Tarkan Erdik , İzzet Öztürk","doi":"10.1016/j.dynatmoce.2025.101555","DOIUrl":"10.1016/j.dynatmoce.2025.101555","url":null,"abstract":"<div><div>Sea surface temperature (SST) is a crucial parameter affecting marine ecosystems and has risen dramatically in recent decades due to climate change. This warming has led to an increase in the frequency and intensity of marine heatwave (MHW) events, prolonged periods of extreme SSTs, which have severe ecological consequences. This study investigates the spatiotemporal variability of SST and MHW characteristics across the interconnected Black, Marmara, and Aegean Seas using satellite-derived daily SST data from 1982 to 2021. Our findings indicate a significant SST increase across all three basins, with the most pronounced warming observed in the Black Sea, followed by the Marmara Sea. SST trends reach 0.8 °C/decade in the eastern Black Sea and 0.3 °C/decade in the Aegean Sea. Since the 2000s, SST warming has accelerated, with the long-term spatial mean trend of 0.57 °C/decade increasing to 0.68 °C/decade. This warming trend has driven a sharp increase in MHW frequency and duration, particularly in the last decade. The highest trend in MHW frequency is observed in the Marmara Sea, with an increase of 1.56 events/decade which further intensified after the 2000s. Beyond long-term trends, MHWs exhibit interannual variability, which correlates with the Eastern Atlantic (EA) and Eastern Atlantic/Western Russia (EAWR) climate indices. Given the rising frequency and duration of MHW events, we also examined mucilage outbreaks in the Marmara Sea during 2007 and 2021. Our analysis suggests that mucilage blooms correspond to years with intense and prolonged MHW events, highlighting MHWs as a potential driver of mucilage formation.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"110 ","pages":"Article 101555"},"PeriodicalIF":1.9,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}