Pub Date : 2025-11-07DOI: 10.1016/j.jastp.2025.106675
Arbind Kumar Amar , Dr Ajay Giri , Dr Mani Kant Paswan
In solar thermal collector systems, inefficient heat transfer between the absorber plate and flowing air leads to reduced thermal performance. This study investigates the enhancement of heat transfer by introducing artificial roughness to the collector in the form of broken arc-shaped baffles on the absorber surface. A three-dimensional numerical model Computational Fluid Dynamics (CFD) is developed using ANSYS Fluent to simulate turbulent airflow and evaluate the thermal behaviour of a modified Solar Air Heater (SAH). The performance of the roughened collector was compared against a conventional smooth-plate design under varying heat flux conditions. The study further analyzed the influence of pitch ratio at a constant roughness height on heat transfer and pressure drop. The results show a significant improvement, with the modified collector achieving a thermal efficiency of 52.34 % under a 1000 W/m2 heat flux, which substantially outperforms the smooth collector. These findings demonstrate the effectiveness of artificial roughness in improving natural convection and overall thermal performance, offering a viable approach for enhancing solar energy utilization.
{"title":"CFD-based numerical analysis of thermal performance in solar thermal collector system with artificial roughness","authors":"Arbind Kumar Amar , Dr Ajay Giri , Dr Mani Kant Paswan","doi":"10.1016/j.jastp.2025.106675","DOIUrl":"10.1016/j.jastp.2025.106675","url":null,"abstract":"<div><div>In solar thermal collector systems, inefficient heat transfer between the absorber plate and flowing air leads to reduced thermal performance. This study investigates the enhancement of heat transfer by introducing artificial roughness to the collector in the form of broken arc-shaped baffles on the absorber surface. A three-dimensional numerical model Computational Fluid Dynamics (CFD) is developed using ANSYS Fluent to simulate turbulent airflow and evaluate the thermal behaviour of a modified Solar Air Heater (SAH). The performance of the roughened collector was compared against a conventional smooth-plate design under varying heat flux conditions. The study further analyzed the influence of pitch ratio at a constant roughness height on heat transfer and pressure drop. The results show a significant improvement, with the modified collector achieving a thermal efficiency of <strong>52.34 %</strong> under a 1000 W/m<sup>2</sup> heat flux, which substantially outperforms the smooth collector. These findings demonstrate the effectiveness of artificial roughness in improving natural convection and overall thermal performance, offering a viable approach for enhancing solar energy utilization.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106675"},"PeriodicalIF":1.9,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691509","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}
According to the generally accepted theory, the field of local active areas arises from the poloidal magnetic field. The field in the polar regions, which is measured directly by magnetographs, can be a proxy for the latter. It has been shown that the mean-field dynamo is undoubtedly the main mechanism that generates solar activity and the 11-year cycle. However, the magnetic flux generated in the dynamo, although it is the genetic basis of solar activity, still does not allow us to unambiguously connect the characteristics of the magnetic field with other indices of solar activity, including the best known indicator, the number of sunspots. Magnetic fields of active regions and spots are formed from the mean magnetic flux. Its most important properties are the threshold nature and the preservation of the full flux. This is why a completely reliable long-term SSN forecast is possible after the occurrence of an equatorial wave approximately 18 months before the maximum. The processes in leptocline play a decisive role in this case.
{"title":"Mean-field dynamo and forecasting of solar activity","authors":"Vladimir Obridko , Antonina Shibalova , Dmitry Sokoloff , Ilya Livshits","doi":"10.1016/j.jastp.2025.106673","DOIUrl":"10.1016/j.jastp.2025.106673","url":null,"abstract":"<div><div>According to the generally accepted theory, the field of local active areas arises from the poloidal magnetic field. The field in the polar regions, which is measured directly by magnetographs, can be a proxy for the latter. It has been shown that the mean-field dynamo is undoubtedly the main mechanism that generates solar activity and the 11-year cycle. However, the magnetic flux generated in the dynamo, although it is the genetic basis of solar activity, still does not allow us to unambiguously connect the characteristics of the magnetic field with other indices of solar activity, including the best known indicator, the number of sunspots. Magnetic fields of active regions and spots are formed from the mean magnetic flux. Its most important properties are the threshold nature and the preservation of the full flux. This is why a completely reliable long-term SSN forecast is possible after the occurrence of an equatorial wave approximately 18 months before the maximum. The processes in leptocline play a decisive role in this case.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106673"},"PeriodicalIF":1.9,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462746","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}
Pub Date : 2025-10-31DOI: 10.1016/j.jastp.2025.106671
Varuliantor Dear , Jiyo Harjosuwito , Annis Siradj Mardiani , Adi Purwono , Afrizal Bahar , Indah Susanti , Satrio Adi Priyambada , Rezy Pradipta
The ionospheric F-layer critical frequency (foF2) is a fundamental parameter for space weather services. Conventionally, foF2 is manually scaled from ionograms using the URSI UAG-23 handbook, which, while accurate, is time-consuming and operator-dependent. This study proposes a simple Quick-Scale (QS) method to rapidly derive daily foF2 values from Frequency-Time Intensity (FTI) plots. The QS method converts FTI images to numeric data using Direct Linear Transformation (DLT) and interactive boundary tracing via a user-friendly Hypertext Markup Language (HTML) tool. The method was tested using Pameungpeuk ionosonde data for year 2020 and validated by four volunteers—two experts and two non-experts. Evaluation shows that the QS method requires approximately 3–4 min per day to extract daily foF2 values, compared to about 24 min needed for URSI UAG-23 manual scaling of 96 ionograms per day. Deviations reached ±2.5 MHz with RMSE and MBE patterns reflecting daily and seasonal ionospheric variations. Correlation coefficients exceeding 0.96 indicate strong agreement with standard foF2 data regardless of operator experience. However, minor time shifts due to image rendering and re-digitization processes were observed, suggesting potential systematic bias for high-precision applications. Overall, the QS method is feasible as a quick-look tool for operational space weather services and can be further refined with bias correction modules to enhance accuracy and temporal precision.
{"title":"Rapid determination of daily ionospheric F-layer critical frequency value using a quick-scale method based on Frequency-Time-Intensity plots","authors":"Varuliantor Dear , Jiyo Harjosuwito , Annis Siradj Mardiani , Adi Purwono , Afrizal Bahar , Indah Susanti , Satrio Adi Priyambada , Rezy Pradipta","doi":"10.1016/j.jastp.2025.106671","DOIUrl":"10.1016/j.jastp.2025.106671","url":null,"abstract":"<div><div>The ionospheric F-layer critical frequency (foF2) is a fundamental parameter for space weather services. Conventionally, foF2 is manually scaled from ionograms using the URSI UAG-23 handbook, which, while accurate, is time-consuming and operator-dependent. This study proposes a simple Quick-Scale (QS) method to rapidly derive daily foF2 values from Frequency-Time Intensity (FTI) plots. The QS method converts FTI images to numeric data using Direct Linear Transformation (DLT) and interactive boundary tracing via a user-friendly Hypertext Markup Language (HTML) tool. The method was tested using Pameungpeuk ionosonde data for year 2020 and validated by four volunteers—two experts and two non-experts. Evaluation shows that the QS method requires approximately 3–4 min per day to extract daily foF2 values, compared to about 24 min needed for URSI UAG-23 manual scaling of 96 ionograms per day. Deviations reached ±2.5 MHz with RMSE and MBE patterns reflecting daily and seasonal ionospheric variations. Correlation coefficients exceeding 0.96 indicate strong agreement with standard foF2 data regardless of operator experience. However, minor time shifts due to image rendering and re-digitization processes were observed, suggesting potential systematic bias for high-precision applications. Overall, the QS method is feasible as a quick-look tool for operational space weather services and can be further refined with bias correction modules to enhance accuracy and temporal precision.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106671"},"PeriodicalIF":1.9,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417545","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}
Pub Date : 2025-10-30DOI: 10.1016/j.jastp.2025.106672
Andrei Moldavanov
A phenomenon of energy transfer in space through a natural energy infrastructure shaped by confinement of the parameters of energy exchange is considered. The infrastructure consists of two interconnected energy spectra intrinsically stemming from the suggested model of an open thermodynamic system. The spectra are based on innate limitation imposed on the efficiency of energy exchange (primary spectrum) and the net passing energy (secondary spectrum). In this context, the primary spectrum creates the quantitative basis for realization of solution in the points of equilibrium, whereas the secondary spectrum forms the guiding energy tubes (GET) for bidirectional transfer between the distant energy points. According to the discussing theory, the family of GETs may be taken as the pathways for energy transfer with the observable signatures of spontaneous shaping, folding, and invariancy. Fundamentally, the conducted simulation for the event of energy transfer in the magnetosphere reveals the existence of connections between GET and the well-known magnetic flux tube, with the major advantage of GET in the more universal character of the underlying theory.
{"title":"Quantization of natural energy pathways in space","authors":"Andrei Moldavanov","doi":"10.1016/j.jastp.2025.106672","DOIUrl":"10.1016/j.jastp.2025.106672","url":null,"abstract":"<div><div>A phenomenon of energy transfer in space through a natural energy infrastructure shaped by confinement of the parameters of energy exchange is considered. The infrastructure consists of two interconnected energy spectra intrinsically stemming from the suggested model of an open thermodynamic system. The spectra are based on innate limitation imposed on the efficiency of energy exchange (primary spectrum) and the net passing energy (secondary spectrum). In this context, the primary spectrum creates the quantitative basis for realization of solution in the points of equilibrium, whereas the secondary spectrum forms the guiding energy tubes (<em>GET</em>) for bidirectional transfer between the distant energy points. According to the discussing theory, the family of <em>GETs</em> may be taken as the pathways for energy transfer with the observable signatures of spontaneous shaping, folding, and invariancy. Fundamentally, the conducted simulation for the event of energy transfer in the magnetosphere reveals the existence of connections between <em>GET</em> and the well-known magnetic flux tube, with the major advantage of <em>GET</em> in the more universal character of the underlying theory.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106672"},"PeriodicalIF":1.9,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462744","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}
Pub Date : 2025-10-29DOI: 10.1016/j.jastp.2025.106674
Alexander Oreshko
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.
研究表明，M.L. Shmatov和K.D. Stephan的文章（Journal of Atmospheric and Solar-Terrestrial Physics, 242(2023) 105,995）包含了许多未经证实和错误的关于实验室球状闪电产生的说法（Oreshko, 2015, 2019; 2021）。Shmatov和Stephan解释了Oreshko的球形对称闪电，由带电粒子组成，以高速运动，作为气体动力学的“发光空气区域”。研究还表明，实验室球形闪电在其起源区域的高速度是由于它在强烈的横向电磁波场中运动而产生的，借助这种电磁波场产生了球形闪电。球型闪电产生区的行电磁波作为一个多级加速器作用于球型闪电粒子。Shmatov和Stephan的假设和结论与实际物理实验的结果及其正确的理论依据完全矛盾。
{"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":"2025-10-29","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}
Pub Date : 2025-10-26DOI: 10.1016/j.jastp.2025.106670
Farahnaz Fazel-Rastgar , S.H. Mthembu
This study investigates a significant cooling event in eastern South Africa that occurred on September 21, 2024. On this day, an unusually strong cold front, linked to either a low-pressure system or a disturbed south polar vortex, brought exceptionally cold air from the southern latitudes into southern Africa. The event is associated with possible sudden stratospheric warmings, which generate warm stratospheric anomalies in the polar vortex region and can influence midlatitude weather. By analyzing the vertical temperature structure during the coldest period, this work explores lower stratosphere–surface thermal coupling. The findings show that temperatures in the lower stratosphere at 10 hPa increased by 2–6 K, while tropopause temperatures rose by about 1.5–10.5 K in eastern South Africa. Meanwhile, the cold mid-tropospheric layer shifted from its usual position around 30–90 gpm down to the surface, leading to the formation of a midlatitude temperature minimum. At the surface, temperatures in the study region dropped by as much as 10 K in the coldest areas compared to normal values. Furthermore, the positive correlation between total ozone and lower stratospheric temperature suggests that extremely high ozone levels over the midlatitudes indicate a warm stratospheric anomaly and possible downward thermal forcing. The snowstorm was intensified by a significant influx of moisture from the Indian Ocean, likely linked to an atmospheric river or a converging weather system. Moisture carried through a narrow corridor of concentrated transport fueled the storm, making the event more severe. Finally, the synoptic evolution showed a cold front and cut-off low moving northward, displacing a deep low-pressure system. The study also highlights the formation of a pressure dipole, with a strong anticyclonic anomaly over South Africa and a cyclonic anomaly over the high latitudes. This pattern drove the intrusion of cold air from the south, advected by ridging anticyclones.
{"title":"Unprecedented abnormal cold weather with snowfall in eastern Southern Africa associated with a disturbed stratospheric south polar vortex: 21 September 2024 storm","authors":"Farahnaz Fazel-Rastgar , S.H. Mthembu","doi":"10.1016/j.jastp.2025.106670","DOIUrl":"10.1016/j.jastp.2025.106670","url":null,"abstract":"<div><div>This study investigates a significant cooling event in eastern South Africa that occurred on September 21, 2024. On this day, an unusually strong cold front, linked to either a low-pressure system or a disturbed south polar vortex, brought exceptionally cold air from the southern latitudes into southern Africa. The event is associated with possible sudden stratospheric warmings, which generate warm stratospheric anomalies in the polar vortex region and can influence midlatitude weather. By analyzing the vertical temperature structure during the coldest period, this work explores lower stratosphere–surface thermal coupling. The findings show that temperatures in the lower stratosphere at 10 hPa increased by 2–6 K, while tropopause temperatures rose by about 1.5–10.5 K in eastern South Africa. Meanwhile, the cold mid-tropospheric layer shifted from its usual position around 30–90 gpm down to the surface, leading to the formation of a midlatitude temperature minimum. At the surface, temperatures in the study region dropped by as much as 10 K in the coldest areas compared to normal values. Furthermore, the positive correlation between total ozone and lower stratospheric temperature suggests that extremely high ozone levels over the midlatitudes indicate a warm stratospheric anomaly and possible downward thermal forcing. The snowstorm was intensified by a significant influx of moisture from the Indian Ocean, likely linked to an atmospheric river or a converging weather system. Moisture carried through a narrow corridor of concentrated transport fueled the storm, making the event more severe. Finally, the synoptic evolution showed a cold front and cut-off low moving northward, displacing a deep low-pressure system. The study also highlights the formation of a pressure dipole, with a strong anticyclonic anomaly over South Africa and a cyclonic anomaly over the high latitudes. This pattern drove the intrusion of cold air from the south, advected by ridging anticyclones.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106670"},"PeriodicalIF":1.9,"publicationDate":"2025-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417544","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}
Pub Date : 2025-10-25DOI: 10.1016/j.jastp.2025.106666
Xiangshun Meng , Yong Wang , Yunlong Zhang , Chengwu Yang , Chen Chang , Haozhe Chi , Yanping Liu
Global climate change has intensified extreme precipitation events, highlighting the urgent need for high-precision short-term rainfall forecasts to ensure railway transportation safety. However, existing meteorological monitoring remains limited by sparse station distribution, observational blind spots, and data inaccuracies. Global reanalysis datasets are hindered by low spatial resolution and precipitation underestimation, while numerical weather prediction models, typically with spatial resolutions exceeding 10 km, cannot satisfy the kilometer-scale disaster prevention demands along railway corridors. To address these limitations, we propose an “FFT–LSTM + post-processing correction” framework, which combines Fast Fourier Transform (FFT) and Long Short-Term Memory (LSTM) networks to extract nonlinear temporal characteristics of precipitation evolution from multivariate meteorological variables. The model further refines precipitation predictions through post-processing correction methods, including Simple Linear Regression (SLR), enhanced Piecewise Linear (PL), and Quantile Mapping (QM). FFT is initially employed to identify the best common period (143 h) among the inputs, guiding the optimal LSTM input window length. Subsequently, tailored correction strategies are applied according to rainfall intensity levels to improve prediction accuracy. Validation based on Meiyu-season data from four representative stations along the Guangzhou–Zhanjiang railway confirms that the proposed approach significantly enhances prediction skill. In hourly predictions, the Probability of Detection (POD) for moderate, heavy, and torrential rainfall reaches 0.562, 0.625, and 0.500, respectively; the Critical Success Index (CSI) for torrential rainfall peaks at 1.0, and the False Alarm Rate (FAR) is reduced to 0.000—indicating substantial gains over baseline models such as ARIMA and XGBoost (CSI <0.08). This study effectively integrates deep learning and statistical correction techniques to overcome key limitations of reanalysis data, providing high-precision support for short-term precipitation forecasting along railways and thereby supporting meteorological disaster mitigation and transportation safety decision-making.
{"title":"Research on hourly precipitation prediction along railways based on ERA5 reanalysis and post-processing correction","authors":"Xiangshun Meng , Yong Wang , Yunlong Zhang , Chengwu Yang , Chen Chang , Haozhe Chi , Yanping Liu","doi":"10.1016/j.jastp.2025.106666","DOIUrl":"10.1016/j.jastp.2025.106666","url":null,"abstract":"<div><div>Global climate change has intensified extreme precipitation events, highlighting the urgent need for high-precision short-term rainfall forecasts to ensure railway transportation safety. However, existing meteorological monitoring remains limited by sparse station distribution, observational blind spots, and data inaccuracies. Global reanalysis datasets are hindered by low spatial resolution and precipitation underestimation, while numerical weather prediction models, typically with spatial resolutions exceeding 10 km, cannot satisfy the kilometer-scale disaster prevention demands along railway corridors. To address these limitations, we propose an “FFT–LSTM + post-processing correction” framework, which combines Fast Fourier Transform (FFT) and Long Short-Term Memory (LSTM) networks to extract nonlinear temporal characteristics of precipitation evolution from multivariate meteorological variables. The model further refines precipitation predictions through post-processing correction methods, including Simple Linear Regression (SLR), enhanced Piecewise Linear (PL), and Quantile Mapping (QM). FFT is initially employed to identify the best common period (143 h) among the inputs, guiding the optimal LSTM input window length. Subsequently, tailored correction strategies are applied according to rainfall intensity levels to improve prediction accuracy. Validation based on Meiyu-season data from four representative stations along the Guangzhou–Zhanjiang railway confirms that the proposed approach significantly enhances prediction skill. In hourly predictions, the Probability of Detection (POD) for moderate, heavy, and torrential rainfall reaches 0.562, 0.625, and 0.500, respectively; the Critical Success Index (CSI) for torrential rainfall peaks at 1.0, and the False Alarm Rate (FAR) is reduced to 0.000—indicating substantial gains over baseline models such as ARIMA and XGBoost (CSI <0.08). This study effectively integrates deep learning and statistical correction techniques to overcome key limitations of reanalysis data, providing high-precision support for short-term precipitation forecasting along railways and thereby supporting meteorological disaster mitigation and transportation safety decision-making.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106666"},"PeriodicalIF":1.9,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417622","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}
Pub Date : 2025-10-25DOI: 10.1016/j.jastp.2025.106667
Maghrabi A
This study employs Lomb periodogram analysis to investigate the spectral characteristics of atmospheric gases (NH3, O3, NOx, NO1, NO2, NMHC), solar radio flux (F10.7), and cosmic rays (CR) in Riyadh from 1999 to 2007. Significant periodicities ranging from 10 days to 1.6 years were identified, with prominent cycles for gases at 454–584 days, 291–293 days, 215 days, 155–171 days, 113 days, 97 days, 39 days, 15–17 days, and 10 days; for F10.7 at 467 days, 255 days, 172 days, and 17 days; and for CR at 489 days, 273 days, 140 days, and 32 days. The 215-day semi-annual and 39-day synoptic cycles, prevalent across multiple gases, alongside the 155–171-day cycle strongly linked to F10.7 and CR, highlight robust seasonal, synoptic, and heliospheric influences. Cross-spectral analyses, along with zero-order and partial correlation analyses, were conducted and confirmed that, while variations in atmospheric gases are subject to terrestrial factors such as meteorological conditions (temperature, humidity, wind), extraterrestrial factors, including solar activity and CR, play a significant role in their variations, with common periodicities validating these influences. Solar activity enhances NOx and NMHC photochemistry, while CR ionization significantly affects O3 and reduces NOx. These extraterrestrial impacts, which warrant further investigation, are critically modulated by meteorological factors. These findings are vital for addressing Riyadh's environmental challenges, supporting sustainable urban development, and enhancing understanding of extraterrestrial influences on climate, atmospheric processes, and environmental sciences.
{"title":"Spectral analyses of short-to medium-term gas cycles in Riyadh: Environmental and cosmic drivers","authors":"Maghrabi A","doi":"10.1016/j.jastp.2025.106667","DOIUrl":"10.1016/j.jastp.2025.106667","url":null,"abstract":"<div><div>This study employs Lomb periodogram analysis to investigate the spectral characteristics of atmospheric gases (NH<sub>3</sub>, O<sub>3</sub>, NOx, NO<sub>1</sub>, NO<sub>2</sub>, NMHC), solar radio flux (F10.7), and cosmic rays (CR) in Riyadh from 1999 to 2007. Significant periodicities ranging from 10 days to 1.6 years were identified, with prominent cycles for gases at 454–584 days, 291–293 days, 215 days, 155–171 days, 113 days, 97 days, 39 days, 15–17 days, and 10 days; for F10.7 at 467 days, 255 days, 172 days, and 17 days; and for CR at 489 days, 273 days, 140 days, and 32 days. The 215-day semi-annual and 39-day synoptic cycles, prevalent across multiple gases, alongside the 155–171-day cycle strongly linked to F10.7 and CR, highlight robust seasonal, synoptic, and heliospheric influences. Cross-spectral analyses, along with zero-order and partial correlation analyses, were conducted and confirmed that, while variations in atmospheric gases are subject to terrestrial factors such as meteorological conditions (temperature, humidity, wind), extraterrestrial factors, including solar activity and CR, play a significant role in their variations, with common periodicities validating these influences. Solar activity enhances NOx and NMHC photochemistry, while CR ionization significantly affects O<sub>3</sub> and reduces NOx. These extraterrestrial impacts, which warrant further investigation, are critically modulated by meteorological factors. These findings are vital for addressing Riyadh's environmental challenges, supporting sustainable urban development, and enhancing understanding of extraterrestrial influences on climate, atmospheric processes, and environmental sciences.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106667"},"PeriodicalIF":1.9,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417618","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}
Pub Date : 2025-10-24DOI: 10.1016/j.jastp.2025.106669
Xu Zhang , Chang Liu , Yixin Liu , Xumei Yuan
Ozone (O3) pollution in China is an increasingly serious problem and Tianjin experiences O3 pollution as its predominant air quality challenge. An analysis of data from 2018 to 2022 indicated that the level of O3 pollution in Tianjin showed a trend of first decreasing and then increasing. The monthly distribution of O3 concentration and the number of O3 exceeding the standard day in Tianjin showed a single peak trend in June. Based on the ground meteorological data and air quality data in Tianjin from 2018 to 2022, the study developed a time-phased generalized additive model (GAM) of meteorological factors (temperature, relative humidity, sunshine duration, pressure, precipitation and wind speed) in Tianjin to analyze their specific effects on O3 concentration. The results showed that the GAM had a high quality and effectively captured the complex nonlinear relationship between O3 and meteorological factors. Seasonal differences were identified in the relationship between O3 concentration and different meteorological factors in Tianjin. Notably, temperature was the dominant meteorological factor affecting O3 concentration change in Tianjin. The interaction of high temperature and medium relative humidity was highly correlated with O3 concentration in Tianjin in summer. The research results are helpful to clarify the influence of meteorological conditions in different seasons on O3 concentration change in Tianjin. It is of great significance for the accurate prediction of O3 pollution and the formulation of pollution prevention and control policies according to local conditions.
{"title":"An analysis of the impacts of meteorological factors on ozone concentration using generalized additive model in Tianjin, China","authors":"Xu Zhang , Chang Liu , Yixin Liu , Xumei Yuan","doi":"10.1016/j.jastp.2025.106669","DOIUrl":"10.1016/j.jastp.2025.106669","url":null,"abstract":"<div><div>Ozone (O<sub>3</sub>) pollution in China is an increasingly serious problem and Tianjin experiences O<sub>3</sub> pollution as its predominant air quality challenge. An analysis of data from 2018 to 2022 indicated that the level of O<sub>3</sub> pollution in Tianjin showed a trend of first decreasing and then increasing. The monthly distribution of O<sub>3</sub> concentration and the number of O<sub>3</sub> exceeding the standard day in Tianjin showed a single peak trend in June. Based on the ground meteorological data and air quality data in Tianjin from 2018 to 2022, the study developed a time-phased generalized additive model (GAM) of meteorological factors (temperature, relative humidity, sunshine duration, pressure, precipitation and wind speed) in Tianjin to analyze their specific effects on O<sub>3</sub> concentration. The results showed that the GAM had a high quality and effectively captured the complex nonlinear relationship between O<sub>3</sub> and meteorological factors. Seasonal differences were identified in the relationship between O<sub>3</sub> concentration and different meteorological factors in Tianjin. Notably, temperature was the dominant meteorological factor affecting O<sub>3</sub> concentration change in Tianjin. The interaction of high temperature and medium relative humidity was highly correlated with O<sub>3</sub> concentration in Tianjin in summer. The research results are helpful to clarify the influence of meteorological conditions in different seasons on O<sub>3</sub> concentration change in Tianjin. It is of great significance for the accurate prediction of O<sub>3</sub> pollution and the formulation of pollution prevention and control policies according to local conditions.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106669"},"PeriodicalIF":1.9,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417621","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}
Pub Date : 2025-10-24DOI: 10.1016/j.jastp.2025.106668
Ting Zhou , Hui Hu , Pan Wang , Mi Zhang , Haoqi Wen , Dan Liu , Wei Liu
Grasping the local ozone pollution characteristics and associated meteorological factors is of great significance for scientific support for ozone (O3) pollution prevention. O3 concentrations and related meteorological data from 2020 to 2022 Yichang City, Hubei were analyzed for exploring the spatiotemporal distribution of O3 concentrations and the impact of associated meteorological factors. The results revealed that O3 pollution in Yichang from 2020 to 2022 exhibited a clear trend of the increasing pollution severity and frequency. High incidences of ozone pollution was between May and September (mainly in summer), but high concentrations of precursors (NO2 and TVOCs) appeared from November to January (mainly in winter), highlighting the decisive role of meteorological conditions in the ozone formation. Moreover, the diurnal variation of O3 concentrations displayed a typical single peak distribution pattern, with hourly O3 concentration (ρ(O3)) peaking at 15:00–16:00, suggesting that ρ(O3) in Yichang was primarily influenced by local emissions. In addition, the sustained high ρ(O3) on exceedance days were related to the local topography and ρ(O3) along the river were strongly influenced by river-land breezes. The difference of meteorological factors between O3 exceedance and non-exceedance days indicated that temperature and relative humidity had more pronounced impacts on ρ(O3). Specifically, 89.6 % of ρ(O3) exceedances occurred under meteorological conditions with temperature ≥25 °C and relative humidity between 25 % and 75 %, with wind speeds consistently below 5 m/s. It was recommended that environmental management departments should deploy related emission control measures in advance when the above meteorological conditions were forecasted, while fully considering the influence of the topography and river-land breeze on pollutant transports to optimize control strategies and coordinated prevention measures.
{"title":"Analysis of ozone pollution characteristics and meteorological factors in Yichang City, Hubei","authors":"Ting Zhou , Hui Hu , Pan Wang , Mi Zhang , Haoqi Wen , Dan Liu , Wei Liu","doi":"10.1016/j.jastp.2025.106668","DOIUrl":"10.1016/j.jastp.2025.106668","url":null,"abstract":"<div><div>Grasping the local ozone pollution characteristics and associated meteorological factors is of great significance for scientific support for ozone (O<sub>3</sub>) pollution prevention. O<sub>3</sub> concentrations and related meteorological data from 2020 to 2022 Yichang City, Hubei were analyzed for exploring the spatiotemporal distribution of O<sub>3</sub> concentrations and the impact of associated meteorological factors. The results revealed that O<sub>3</sub> pollution in Yichang from 2020 to 2022 exhibited a clear trend of the increasing pollution severity and frequency. High incidences of ozone pollution was between May and September (mainly in summer), but high concentrations of precursors (NO<sub>2</sub> and TVOCs) appeared from November to January (mainly in winter), highlighting the decisive role of meteorological conditions in the ozone formation. Moreover, the diurnal variation of O<sub>3</sub> concentrations displayed a typical single peak distribution pattern, with hourly O<sub>3</sub> concentration (ρ(O<sub>3</sub>)) peaking at 15:00–16:00, suggesting that ρ(O<sub>3</sub>) in Yichang was primarily influenced by local emissions. In addition, the sustained high ρ(O<sub>3</sub>) on exceedance days were related to the local topography and ρ(O<sub>3</sub>) along the river were strongly influenced by river-land breezes. The difference of meteorological factors between O<sub>3</sub> exceedance and non-exceedance days indicated that temperature and relative humidity had more pronounced impacts on ρ(O<sub>3</sub>). Specifically, 89.6 % of ρ(O<sub>3</sub>) exceedances occurred under meteorological conditions with temperature ≥25 °C and relative humidity between 25 % and 75 %, with wind speeds consistently below 5 m/s. It was recommended that environmental management departments should deploy related emission control measures in advance when the above meteorological conditions were forecasted, while fully considering the influence of the topography and river-land breeze on pollutant transports to optimize control strategies and coordinated prevention measures.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"277 ","pages":"Article 106668"},"PeriodicalIF":1.9,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145516884","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}
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