Journal of Atmospheric and Solar-Terrestrial Physics最新文献

{"title":"Supervised land cover classification of the Indian Sundarbans mangrove forest using random forest and Landsat imagery","authors":"M. Kasiselvanathan,&nbsp;P. Sridevi","doi":"10.1016/j.jastp.2025.106663","DOIUrl":"10.1016/j.jastp.2025.106663","url":null,"abstract":"<div><div>Rapid population enhancement and economic development have significantly changed land use and land cover (LULC) in ecologically sensitive Sundarbans, the world's most fragile ecosystem. Accurate classification of LULC is important for environmental monitoring, resource management, and policy-making. In the present paper, the authors have employed a machine learning (ML) technique, Random Forest (RF), to classify land cover changes in the Sundarbans over two time periods: 2003, and 2023. Landsat-7 and Landsat-8 satellite imagery have been used for land cover (LC) analysis, followed by data pre-processing techniques including layer stacking, mosaicking, and spectral signature collection. Around 640 and 840 training samples have been used for classification, for the year 2003 and 2023 respectively with 30 % samples used for validation. The RF model utilized 500 trees (n-tree) and four variables at each split (m-try). The accuracy has been assessed with confusion matrices, and Kappa statistics showing an accuracy of 0.84 and 0.85 for the year 2003 and 2023 respectively. The result reveals an increase in sparse forest, open land, and sand bar, and decline in water bodies and dense forest. The reason may be due to anthropogenic activities and climate-induced factors such as rising sea levels and storm surges. The findings indicate Sundarbans ecosystem's susceptibility and the necessity of sustainable management techniques. This study indicates that future research should focus on longer time-series analysis, improved scalability, and cloud platform integration to improve. The research demonstrates that ML-based land cover classification can be a useful monitoring tool with high accuracy for environmental conservation.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106663"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324936","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":"How accurately can the ionosphere peak electron density be modeled?","authors":"P.G. Richards ,&nbsp;J.T. Emmert","doi":"10.1016/j.jastp.2025.106657","DOIUrl":"10.1016/j.jastp.2025.106657","url":null,"abstract":"<div><div>This study examines how well the ionosphere peak electron density can be simulated with the Field Line Interhemispheric Plasma (FLIP) model given the current knowledge of chemistry, solar EUV radiation, and thermosphere densities. The simulations were conducted at many mid-latitude ionosonde stations over a wide range of solar activity conditions to compare the different model results from the new NRLMSIS 2.0 thermosphere model (Emmert et al., 2020) with the older NRLMSISE-00 model (Picone et al., 2002). These FLIP model-data results may help isolate times and places for needed improvement to the thermosphere models. The NRLMSISE-00 version of the FLIP model (FLIP0) yields daytime peak F-region electron density (<em>N</em>_<em>m</em><em>F</em>₂) agreement well within the measurement and model errors at most stations in the Southern Hemisphere. In the Northern Hemisphere, there is good model-data agreement around the June solstice but significant differences in the American and European sectors. The NRLMSIS 2.0 version (FLIP2) produces slightly lower <em>N</em>_<em>m</em><em>F</em>₂ values overall than FLIP0, but it causes a significant overestimation in the Australian sector at the March equinox for high solar activity. Neither the FLIP0 nor FLIP2 model adequately captures the changes in <em>N</em>_<em>m</em><em>F</em>₂ due to enhanced magnetic activity, especially the greater variability near the equinoxes, that has been attributed to the orientation of the Earth's rotation axis with the solar wind. The data show that magnetic activity is more important than solar activity for determining changes in <em>N</em>_<em>m</em><em>F</em>₂ over a solar rotation period.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106657"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324934","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":"Scale-dependent coupling between galactic cosmic rays and trace gases revealed by multifractal analysis","authors":"D. Sierra-Porta","doi":"10.1016/j.jastp.2025.106661","DOIUrl":"10.1016/j.jastp.2025.106661","url":null,"abstract":"<div><div>Galactic cosmic rays (GCR) modulate atmospheric ionisation and may influence reactive greenhouse gases, yet linear correlations have proved inconclusive. We analyse 74<!--> <!-->328 hourly observations (2016–2024) of pressure-corrected neutron-monitor counts and co-located CH<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> and O<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> mixing ratios from the high-alpine Jungfraujoch station using Multifractal Detrended Fluctuation Analysis (MFDFA) and its bivariate extension (MFDCCA). Cosmic rays exhibit a narrow, quasi-monofractal singularity spectrum (<span><math><mrow><mi>Δ</mi><msub><mrow><mi>α</mi></mrow><mrow><mtext>full</mtext></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>43</mn></mrow></math></span>), consistent with heliospheric modulation as a single dominant driver, whereas O<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> and CH<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> display progressively broader spectra (<span><math><mrow><mi>Δ</mi><mi>α</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>78</mn></mrow></math></span> and 0.84). Cross-Hurst exponents exceed unity for small-to-moderate fluctuations, indicating super-persistent joint variability on 1–7 d (O<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>) and 7–30 d (CH<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>) horizons—time-scales compatible with HO<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>/NO<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span> chemistry triggered by GCR ionisation. Quadratic fits to the cross-singularity spectra yield half-maximum widths of 0.39 (CH<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>–GCR) and <span><math><mrow><mo>&lt;</mo><mn>0</mn><mo>.</mo><mn>33</mn></mrow></math></span> (O<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>–GCR), quantifying a broader amplitude hierarchy for methane. Extreme gas anomalies, by contrast, show weak cross persistence, implicating dynamical intrusions rather than ionisation. Multifractal metrics thus expose a scale-selective GCR imprint masked in Pearson and Spearman statistics and suggest that incorporating GCR flux as a multiscale covariate could improve sub-monthly O<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>/CH<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> predictions. The approach provides a transferable framework for disentangling cosmic-ray forcing from chemical and dynamical controls in other trace-gas records.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106661"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145359170","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":"Directional characteristics of low-level jet over the Arabian Sea and its impact on monsoon precipitation over the Western Ghats","authors":"Xinming Zhang ,&nbsp;M.V. Subrahmanyam ,&nbsp;Zhou Le ,&nbsp;Dongxiao Wang","doi":"10.1016/j.jastp.2025.106665","DOIUrl":"10.1016/j.jastp.2025.106665","url":null,"abstract":"<div><div>Previous studies have conducted a comprehensive examination of the impact of wind speed on monsoon precipitation; however, the significance of wind direction remains largely unexplored. This analysis utilizes ERA-5 reanalysis data to quantitatively investigate the directional characteristics of the Arabian Sea low-level jet (LLJ) over the last four decades. It applies wind angle metrics to evaluate the LLJ's direction and its influence on monsoon precipitation over the Western Ghats (WG), with a larger angle signifying that the LLJ is more aligned with the southerly wind. At 925 hPa, the LLJ exhibits a greater wind angle than at 850 hPa, showing an upward trend. This finding suggests a northerly movement of the LLJ, potentially associated with the Pacific Decadal Oscillation. Statistical analysis reveals that a larger LLJ angle is associated with heightened precipitation on the northern windward slopes of the WG, and precipitation decreases in the southern regions, suggesting the influence of the LLJ's directional changes on precipitation patterns. The results offer valuable perspectives for enhancing monsoon predictions and deepening our scientific comprehension of the relationship between the LLJ and precipitation.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106665"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145359095","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 influence of the ionospheric electric potential on outgoing longwave radiation in the troposphere during the May 11, 2024 geomagnetic superstorm","authors":"A.A. Karakhanyan,&nbsp;S.I. Molodykh","doi":"10.1016/j.jastp.2025.106658","DOIUrl":"10.1016/j.jastp.2025.106658","url":null,"abstract":"<div><div>Meteorological records show an increase in the intensity and frequency of hazardous weather phenomena on the planet. Solar activity is one of the climate-forming factors and, along with carbon dioxide, can influence the Earth's climate. The indirect mechanism of solar activity influence on the climate system is discussed. The ionospheric electric potential (EP), caused by changes in the solar wind and interplanetary magnetic field, plays an important role in this mechanism. Our investigation studies the possibility of using EP as an indicator of solar activity to analyze the outgoing longwave radiation (OLR) response during an individual powerful geomagnetic disturbance, such as the May 11, 2024 geomagnetic superstorm. The EP contrast averaged for the latitudes region above 60° N correlates well with high-, mid-, and low-latitude geomagnetic indices. Unlike geomagnetic indices, the spatial distribution of the EP enables us to analyze the spatial structure of OLR's response to disturbances. Changes in EP have been shown to lead to a decrease in OLR. However, the contribution of meteorological variability on time scales of less than one month must be considered for individual powerful magnetic storms. The EP can therefore be used as new indicator of solar activity to solve the solar-tropospheric problem.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106658"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324923","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":"Enhanced estimation of seasonal irradiance patterns: The adapted time synchronous average method","authors":"Mohammed Telidjane ,&nbsp;Benaoumeur Bakhti","doi":"10.1016/j.jastp.2025.106620","DOIUrl":"10.1016/j.jastp.2025.106620","url":null,"abstract":"<div><div>Accurately separating the cyclic pattern from background noise in irradiance data is critical for various applications, including monitoring photovoltaic panels. However, seasonality, evident as amplitude modulation in the irradiance waveform, poses a significant challenge to existing methods like Time Synchronous Averaging (TSA) and Cepstral Editing (CE). These methods struggle to effectively remove the influence of seasonality on the estimated cyclic pattern. This work proposes a novel method called the Adapted Time Synchronous Average (ATSA) to address these limitations. The new approach is inspired by the application of cyclostationary tools used in mechanical signals of rotating machinery. ATSA employs a three-step approach: signal normalization to mitigate seasonality, TSA estimation using the normalized data, and adaptive filtering for signal reconstruction. Our analysis demonstrates that ATSA outperforms TSA and CE in separating the cyclic pattern from the stochastic noise component in irradiance data.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106620"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097851","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":"Pre-seismic ionospheric disturbances (PIDs) associated With 2021 Mw 7.5 Northern Peru earthquake: GNSS and ground uplift observations","authors":"Oluwasegun M. Adebayo ,&nbsp;Esfhan A. Kherani ,&nbsp;Alexandre A. Pimenta ,&nbsp;Babatunde Rabiu","doi":"10.1016/j.jastp.2025.106644","DOIUrl":"10.1016/j.jastp.2025.106644","url":null,"abstract":"<div><div>Predicting natural disasters such as earthquakes remains a major challenge in geosciences, with critical implications for early warning systems and disaster risk reduction. Among various precursory signals, ionospheric anomalies have gained increasing attention as potential indicators of impending seismic events. In this study, we examine pre-seismic ionospheric disturbances (PIDs) associated with the Mw 7.5 Northern Peru earthquake on November 28, 2021, using Global Navigation Satellite System (GNSS) Total Electron Content (TEC) and ground vertical velocity data. Significant sequential negative TEC anomalies were observed up to two hours prior to the mainshock, with multiple disturbances recorded by several GNSS receivers. The amplitudes of these disturbances increased as the earthquake approached, suggesting a progressive ionospheric response to the buildup of tectonic stress. Spectral analysis using the Short-Time Fourier Transform revealed center frequencies between 3.63 mHz and 4.80 mHz — within the acoustic/infrasonic range — indicating that such waves, possibly generated by foreshocks, may be responsible for these PIDs. To rule out other sources of TEC anomalies, we examined the TEC data for the previous day along the same trajectories and found no similar disturbances. Furthermore, geomagnetic conditions were quiet during the period, as indicated by Kp and Dst indexes two days before and after the earthquake. These findings contribute to the understanding of seismo-ionospheric coupling and highlight the potential role of ionospheric monitoring as a complementary approach to conventional seismic methods in earthquake early warning systems.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106644"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221899","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":"Impact of climatic factors on volume aerosol size distribution over Northern India","authors":"Nabin Sharma ,&nbsp;Sishir Dahal ,&nbsp;Sunil Kumar Chaurasiya ,&nbsp;Sarvan Kumar ,&nbsp;Kalpana Patel","doi":"10.1016/j.jastp.2025.106633","DOIUrl":"10.1016/j.jastp.2025.106633","url":null,"abstract":"<div><div>The correlation between climatic factors and the volume aerosol size distribution (V-ASD), which was extracted from AERONET data for 5 years at five monitoring sites throughout Northern India, has been investigated. Fine-mode aerosols (&lt;0.58 μm) showed negative correlations with rainfall (RF) and relative humidity (RH), where RH enhances hygroscopic growth, making particles more prone to removal by precipitation scavenging. Depending on the station, the correlation between Wind Speed (WS) and V-ASD varied. The pre-monsoon period was marked by greater WS and Boundary Layer Height, which improved aerosol dispersion and mixing, but the monsoon period (June–September) regularly raised RF and RH, according to seasonal changes. At most sites, coarse-mode aerosols (&gt;0.58 μm) showed a positive correlation with temperature, whereas fine-mode particles showed negative correlations with both temperature and relative humidity. Coarse particle development was greatly impacted by temperature-driven processes, especially at Gandhi College and Kanpur. These results demonstrate the intricate relationships that exist in North India between regional climatic factors and aerosol size distributions.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106633"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156487","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":"Answers to “Questions regarding alleged laboratory creation of ball lightning” from the standpoint of plasma physics and electrodynamics","authors":"Alexander Oreshko","doi":"10.1016/j.jastp.2025.106674","DOIUrl":"10.1016/j.jastp.2025.106674","url":null,"abstract":"<div><div>It is shown that the article by M.L. Shmatov's and K.D. Stephan's (Journal of Atmospheric and Solar-Terrestrial Physics, 242 (2023) 105,995) contains a number of unsubstantiated and erroneous claims on the produced in the laboratory ball lightning (Oreshko, 2015, 2019; 2021). Shmatov and Stephan interpreted Oreshko's spherically symmetric ball lightnings, consisting of charged particles and moving at high velocity, as gas-dynamic “regions of light-emitting air”. It is also shown that the high velocity of laboratory ball lightning in the region of its origin is achieved due to the fact that it moves in the field of an intense transverse electromagnetic wave with the help of which the generation of ball lightning occurred. The traveling electromagnetic wave in the region of ball lightning generation acts on its particles as a multi-stage accelerator. The assumptions and conclusions of Shmatov and Stephan completely contradict the results of real physical experiments and their correct theoretical substantiation.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106674"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462745","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":"Identification and distribution of wet and dry season in the 70 most populated cities in India","authors":"Sumanta Dandapath ,&nbsp;Abhijit Patil ,&nbsp;Dhanashri Suresh Shinde ,&nbsp;Praveen Kumar Pathak","doi":"10.1016/j.jastp.2025.106649","DOIUrl":"10.1016/j.jastp.2025.106649","url":null,"abstract":"<div><div>In this paper, for the first time, we have attempted to identify the length and distribution of the wet and dry season of the 70 most populated cities in India based on the relative intra-annual distribution of rainfall observed during the last three decades (1991–2020). The wet season in the cities under investigation is rather continuous and usually lasts for 4–8 months. The distribution of the wet months however indicates significant variation, particularly for the cities located in the southern and northern periphery of the country. The cities located in the remaining areas even though have been receiving rainfall primarily during the Indian Summer Monsoon (ISM), the length of the wet season however varies among them. The present study also highlights that the average length of the wet season in India is not always four months; instead, it is a little over 5 months long in general. The length and distribution of the dry season also indicate that most cities receive a very negligible amount of rainfall for more than five months. The average amount of rainfall received by the cities during their respective dry season (4.1 %) is about 22 times lower than the average amount of rainfall received during their respective wet season (90.2 %). Noticeable variation in the amount of annual rainfall, length of dry and wet season, and amount of rainfall received in their respective wet and dry season among cities within each of the four homogeneous regions is also a significant finding of the present work.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106649"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221941","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}