Journal of Atmospheric and Solar-Terrestrial Physics最新文献

{"title":"Development of Land Use Regression (LUR) models and high-resolution spatial mapping of criteria air pollutants: Leveraging Delhi's continuous air monitoring network and remote sensing data","authors":"Pratyush Agrawal ,&nbsp;Adithi R. Upadhya ,&nbsp;Srishti S ,&nbsp;Mahesh Kalshetty ,&nbsp;Padmavati Kulkarni ,&nbsp;Meenakshi Kushwaha ,&nbsp;V. Sreekanth","doi":"10.1016/j.jastp.2024.106385","DOIUrl":"10.1016/j.jastp.2024.106385","url":null,"abstract":"<div><div>High-resolution air pollution maps can help researchers and governments better characterize and mitigate pollution levels in a given region. Land Use Regression (LUR) modeling is a statistical approach capable of predicting pollution levels at a high spatial resolution. In this study, we used pollution data (for the calendar year 2019) from a dense (compared to other Indian regions) regulatory monitoring network in Delhi, India, to develop simple linear and interpretable LUR models for various criteria pollutants. The observed annual mean PM_2.5 and PM₁₀ over Delhi were found to be ∼110 μg m⁻³ and 220 μg m⁻³, respectively. The PM concentration levels were 2.5–4 times higher than the prescribed national ambient standards, while the gaseous criteria pollutants were found to be within the standards (over most of the study area). The performance of the developed LUR models ranged from poor to moderate levels (adjusted-R² values of the models were between 0.14 and 0.63). Land use and road-network related variables were found to be the most common predictors of the observed pollution levels. Moderately performing models (11 out of the developed 20) were then used to predict pollution levels at 50 m spatial intervals and to identify the most polluted districts. The advantages and limitations of using the existing regulatory network data for LUR development, and the other probable potential reasons responsible for the underperformance of the developed models are extensively discussed. To our knowledge, this is one of the few studies carried over Indian region to develop LUR models utilizing regulatory monitoring network data.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106385"},"PeriodicalIF":1.8,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698824","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":"Characterization of gravity wave events detected in the low ionosphere at the Brazilian Antarctic Station","authors":"Luís Tiago Medeiros Raunheitte ,&nbsp;Emilia Correia ,&nbsp;Jean Pierre Raulin ,&nbsp;José Valentin Bageston","doi":"10.1016/j.jastp.2024.106383","DOIUrl":"10.1016/j.jastp.2024.106383","url":null,"abstract":"<div><div>Here we present the characteristics of three distinct types of Gravity Wave (GW) events as detected in the low ionosphere using very low frequencies (VLF) radio measurements performed at the EACF, Brazilian Antarctic Station Comandante Ferraz (62° 5′ 6″ S, 58° 24′ 12″ W), on King George Island. GWs in the low ionosphere produce oscillations in the electron density, which can be detected as amplitude and phase fluctuations of the VLF signals. The properties of the GW events are obtained using Morlet's Wavelet analysis, which gives the period of the waves, and their occurrence time. The period and duration of the GW events obtained using the VLF technique presented good agreement with ones previously obtained from airglow observations from a co-located all-sky imager. The VLF detection of the mesospheric front showed the same morphology seen with the imager with four crests identified, and the wave activity presented similar period range (∼4–16 min) as observed by airglow (∼6 min) with a period peak of 14 min equal to the spectral analysis of the concurrent OH temperature data. The activity associated with the band event presented similar period of ∼10 min (imager observed 13 min), same duration of 4 h as well as peak intensity just before 05:00 UT. The ripple detection showed the same period of 8 min as the airglow observations and similar duration of around 25 min. By considering two distinct VLF paths it was also possible to analyze the direction and velocity of propagation for the mesospheric front event, which gives 96.0 (±4.8) ms⁻¹ in the East direction in agreement with the velocity of ∼92 ms⁻¹ in the Northeast direction obtained from the airglow observations.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106383"},"PeriodicalIF":1.8,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651724","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 assessment of empirical random forest family's model in simulating future streamflow in different basin of Sarawak, Malaysia","authors":"Zulfaqar Sa’adi ,&nbsp;Shamsuddin Shahid ,&nbsp;Mohammed Sanusi Shiru ,&nbsp;Kamal Ahmed ,&nbsp;Mahiuddin Alamgir ,&nbsp;Mohamad Rajab Houmsi ,&nbsp;Lama Nasrallah Houmsi","doi":"10.1016/j.jastp.2024.106381","DOIUrl":"10.1016/j.jastp.2024.106381","url":null,"abstract":"<div><div>In Sarawak, a region highly vulnerable to climate change, the translation of climate-induced changes in rainfall to river flow is non-linear, presenting a challenge for water resource managers. This research investigates the impact of climate change on hydrological processes in Sarawak, Malaysia, with a specific focus on assessing future spatiotemporal variations in streamflow. The families of Random Forest (RF) empirical models based on data mining techniques were compared and utilized to develop a continuous hydrologic model. Then, by incorporating rainfall and evapotranspiration future projection prepared based on RF past performance statistical downscaling, the top performing RF empirical hydrological model was used for future streamflow projection. The results showed that despite an expected increase in rainfall, the RFR (Random Forest by Randomization) empirical hydrological model demonstrated a potential decrease in river runoff due to heightened evapotranspiration demands associated with rising temperatures. The examination of climate-induced alterations in both rainfall and evapotranspiration patterns revealed a consistent decrease in river discharges during the early to middle period across Sarawak, followed by a shift towards an increasing trend by the end of the 21st century. The central region along the Rajang basin exhibited a prevailing decrease in river discharge, with contrasting patterns in the last part of the century. The northern region displayed diverse trends, with some basins experiencing decreases in river runoff despite augmented rainfall, emphasizing the heterogeneity in response. By employing empirical models, and projecting future scenarios, the study contributes to a better understanding of climate change impacts on hydrology in the region, essential for effective water resource management and environmental conservation.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106381"},"PeriodicalIF":1.8,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587214","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":"Air-sea interactions and Bay of Bengal basin wide variability with respect to long tracked cyclone ‘Viyaru’","authors":"Gopi Krishna Podapati ,&nbsp;Pushpalatha Tadivalasa ,&nbsp;Sreenivas Pentakota ,&nbsp;Dandi A. Ramu ,&nbsp;Sagar V. Gade","doi":"10.1016/j.jastp.2024.106382","DOIUrl":"10.1016/j.jastp.2024.106382","url":null,"abstract":"<div><div>The Bay of Bengal (BoB) is a potentially active region for the formation of the Tropical Cyclones (TCs) and accounts for about 6% of the global annual total number of tropical storms. These TCs occur during the pre-monsoon (March–May) and post-monsoon (October–November) seasons over the BoB. Among all the pre-monsoon cyclones that occurred from 1993 to 2019, we have identified that the “Viyaru” is a typical one originated in the southern BoB, propagated approximately through the middle of the bay, and made landfall over the northern BoB. The cyclonic storm Viyaru caused a basin-scale sea surface cooling of 0.35 °C by increasing the mixed layer depth by 3.5 m over the Bay of Bengal. An analysis of mixed layer heat budget terms infers that reduced short wave radiation and increased latent heat fluxes as the key factors responsible for basin-wide cooling associated with the Viyaru cyclone. We have also found that the enhanced entrainment processes even after the dissipation of the Viyaru cyclone had resulted in a post-cyclone basin-wide cooling tendency over the Bay of Bengal. The present study exemplifies the role of a pre-monsoon cyclone (Viyaru) in impacting the Bay of Bengal basin-scale variability of surface Physical Oceanographic variables and associated processes.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106382"},"PeriodicalIF":1.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572801","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":"Observation of sporadic E layer altitude partially modulated by the Traveling Ionospheric Disturbances at high latitudes over Zhongshan station","authors":"Alicreance Hiyadutuje ,&nbsp;Michael J. Kosch ,&nbsp;John Bosco Habarulema ,&nbsp;Xiangcai Chen ,&nbsp;Judy A.E. Stephenson ,&nbsp;Tshimangadzo Merline Matamba ,&nbsp;Mpho Tshisaphungo","doi":"10.1016/j.jastp.2024.106377","DOIUrl":"10.1016/j.jastp.2024.106377","url":null,"abstract":"<div><div>At Zhongshan (69° S, 76° E) Antarctica we investigate the sporadic <span><math><mi>E</mi></math></span> (<span><math><mrow><mi>E</mi><mi>s</mi></mrow></math></span>)-layer virtual height modulation, observed by an ionosonde, during the passage of the Medium-Scale Traveling Ionospheric Disturbances (MSTIDs), observed by a SuperDARN radar. Two events were identified, on 04 October 2011 at 07:00 - 12:00 UT and 29 February 2012 at 00:00 - 04:00 UT with periods of <span><math><mo>∼</mo></math></span>15.0 and <span><math><mo>∼</mo></math></span>12.0 min, respectively. The magnitude of average height modulation of the <span><math><mrow><mi>E</mi><mi>s</mi></mrow></math></span>-layer was <span><math><mo>∼</mo></math></span>3.7 to <span><math><mo>∼</mo></math></span>17.1 and <span><math><mo>∼</mo></math></span>0.5 to <span><math><mo>∼</mo></math></span>7.3 km, respectively, with the same periods as the MSTIDs. Ray tracing during the events shows that the likely MSTID propagation was up to <span><math><mo>∼</mo></math></span>300 km in the ionospheric <span><math><mi>F</mi></math></span>-region. The computed ion vertical drift velocity using SuperDARN radar and magnetometer data, and <span><math><mrow><mi>E</mi><mi>s</mi></mrow></math></span>-layer altitude modulation observed by the ionosonde have moderate to strong positive correlation of 0.71 ± 0.22 and 0.51 ± 0.16, respectively. We show that the MSTIDs polarization electric field, which is mapped down from the <span><math><mi>F</mi></math></span>-region along the near-vertical magnetic field, moderately contributes to the modulation of the <span><math><mrow><mi>E</mi><mi>s</mi></mrow></math></span> layer altitude via the <span><math><mrow><mi>E</mi><mo>×</mo><mi>B</mi></mrow></math></span> drift mechanism.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106377"},"PeriodicalIF":1.8,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553349","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":"PAOFCDN: A novel method for predictive analysis of solar irradiance","authors":"Sana Mujeeb","doi":"10.1016/j.jastp.2024.106376","DOIUrl":"10.1016/j.jastp.2024.106376","url":null,"abstract":"<div><div>Solar photovoltaic power is the most feasible Renewable Energy Source (RES) for Pakistan, due to ample sunlight availability throughout the year. Since solar photovoltaic power is primarily dependent on solar irradiance, forecasting of solar irradiance is essential for reliable, secure and effective incorporation of solar photovoltaic power in power systems. Considering the importance of solar irradiance forecasting, in this study, predictive analysis of Islamabad’s solar irradiance is performed by using a novel proposed model named as Pelican Algorithm-based Optimized Fully-Connected Deep Network (PAOFCDN). The initial weights of Fully-Connected Deep Network (FCDN) are optimized through an effective optimization technique known as Pelican optimization. The accuracy of the optimized network PAOFCDN is enhanced many fold as compared to the FCDN network trained with randomly initialized weights. The inherent issue of poor generalization in FCDN is also resolved by optimization. The superior performance of PAOFCDN is evident from its comparative evaluation with existing benchmark methods, i.e., Long Short-Term Memory (LSTM), Support Vector Regression (SVR), Least Square Boosting (LSBoost) and standard FCDN. PAOFCDN achieves the least Normalized Root Mean Square Error (NRMSE) of 0.0503 as compared to 0.1179 of LSTM, 0.1256 of FCDN, and 0.2992 of SVR and LSBoost. The proposed model is applied to three real-world solar irradiance datasets having different resolutions of 10-minutes, hourly and daily. This study took the initiative of performing predictions on three datasets having multiple resolutions in perspective of south asia.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106376"},"PeriodicalIF":1.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698823","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":"On the low-latitude ionospheric irregularities under geomagnetically active and quiet conditions using NavIC observables: A spectral analysis approach","authors":"Sumanjit Chakraborty ,&nbsp;Abhirup Datta","doi":"10.1016/j.jastp.2024.106369","DOIUrl":"10.1016/j.jastp.2024.106369","url":null,"abstract":"<div><div>Ionospheric irregularities and associated scintillations under geomagnetically active/quiet conditions have detrimental effects on the reliability and performance of space- and ground-based navigation satellite systems, especially over the low-latitude region. The current work investigates the low-latitude ionospheric irregularities using the phase screen theory and the corresponding temporal Power Spectral Density (PSD) analysis to present an estimate of the outer irregularity scale sizes over these locations. The study uses simultaneous L5 signal C/N<span><math><msub><mrow></mrow><mrow><mi>o</mi></mrow></msub></math></span> observations of NavIC (a set of GEO and GSO navigation satellite systems) near the northern crest of EIA (Indore: 22.52<span><math><msup><mrow></mrow><mrow><mo>∘</mo></mrow></msup></math></span>N, 75.92<span><math><msup><mrow></mrow><mrow><mo>∘</mo></mrow></msup></math></span>E, dip: 32.23<span><math><msup><mrow></mrow><mrow><mo>∘</mo></mrow></msup></math></span>N) and in between the crest and the dip equator (Hyderabad: 17.42<span><math><msup><mrow></mrow><mrow><mo>∘</mo></mrow></msup></math></span>N, 78.55<span><math><msup><mrow></mrow><mrow><mo>∘</mo></mrow></msup></math></span>E, dip: 21.69<span><math><msup><mrow></mrow><mrow><mo>∘</mo></mrow></msup></math></span>N). The study period (2017–2018) covers disturbed and quiet-time conditions in the declining phase of the solar cycle 24. The PSD analysis brings forward the presence of irregularities, of the order of a few hundred meters during weak-to-moderate and quiet-time conditions and up to a few km during the strong event, over both locations. The ROTI values validate the presence of such structures in the Indian region. Furthermore, only for the strong event, a time delay of scintillation occurrence over Indore, with values of 36 min and 50 min for NavIC satellites (PRNs) 5 and 6, respectively, from scintillation occurrence at Hyderabad is observed, suggesting a poleward evolution of irregularity structures. Further observations show a westward propagation of these structures on this day. This study brings forward the advantage of utilizing continuous data from the GEO and GSO satellite systems in understanding the evolution and propagation of the ionospheric irregularities over the low-latitude region.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106369"},"PeriodicalIF":1.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531338","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 aerosols on atmospheric electrification over East and West Africa","authors":"B. Mmame ,&nbsp;C. Ngongondo","doi":"10.1016/j.jastp.2024.106375","DOIUrl":"10.1016/j.jastp.2024.106375","url":null,"abstract":"<div><div>Studies have shown that atmospheric aerosols can modify cloud microphysics. The influence of atmospheric aerosols on mechanisms that lead to generation of lightning is very complex and not fully understood. Recent studies have also revealed that, west Africa has high concentration of atmospheric aerosols due to localized wind which diverge from Sahara desert to this area. This study investigates the impact of atmospheric aerosols on lightning flash rate over east and west Africa by utilizing aerosol optical depth (AOD) from Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis data, convective available potential energy (CAPE), potential temperature, surface relative humidity, clouds and lightning flash rate. Pearson correlation and partial correlation have been applied between lightning flash rate and AOD, humidity, clouds, CAPE as well as potential temperature. Quantitative results show that there is a strong positive correlation (<span><math><mo>∼</mo></math></span>0.75) between lightning flash rate and aerosols under low concentration of aerosols (AOD <span><math><mo>≤</mo></math></span> 0.6) due to aerosol microphysics effect. In the presence of high aerosol concentration (AOD <span><math><mo>&gt;</mo></math></span> 0.6), the correlation coefficient between lightning flash rate and aerosols is somehow weak (<span><math><mo>∼</mo></math></span>0.45) due to decrease in the number of ice particles as well as radiation effect of aerosols. However, the correlation coefficient between lightning flash rate and CAPE, clouds and potential temperature are all positive under both high and low concentration of atmospheric aerosols.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106375"},"PeriodicalIF":1.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531339","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":"Changes in turbulent processes caused by atmospheric gravity waves from troposphere","authors":"Liudmyla Kozak ,&nbsp;Istvan Ballai ,&nbsp;Viktor Fedun ,&nbsp;Elena A. Kronberg ,&nbsp;Aljona Bloecker ,&nbsp;Bohdan Petrenko","doi":"10.1016/j.jastp.2024.106364","DOIUrl":"10.1016/j.jastp.2024.106364","url":null,"abstract":"<div><div>We have determined that changes in temperature and wind speed recorded in the Earth‘s upper atmosphere above tropospheric sources (hurricanes) can be explained by the propagation of atmospheric gravity waves (AGW). We carried out modeling of the propagation of AGW with a period of 65 min and <span><math><mrow><msub><mrow><mi>k</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>=</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math></span> m⁻¹ using multi-layer methods in a non-homogeneous, non-isothermal atmosphere, taking into account viscosity and thermal conductivity. We obtained that disturbances in the horizontal component of the velocity are five times greater than the increase in the vertical component of the velocity, and temperature changes can reach 30 K. We should note that the disturbances of temperature and pressure as a result of AGW spreading are superimposed onto the usual view of changes of pressure and temperature with the altitude and reach the maximum amplitude in the range from 90 to 100 km. The obtained changes in the temperature of the upper atmosphere and the velocity with height as a result of the presence of AGW made it possible to estimate the values of the coefficients of turbulent viscosity and thermal conductivity in the upper atmosphere of the Earth above tropospheric energy sources. Intensification of turbulent processes was recorded in the range of altitudes from 75 to 100 km.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106364"},"PeriodicalIF":1.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537214","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":"Dynamical complexity and multifractal analysis of geomagnetic activities at high temporal scales over three solar cycles","authors":"Samuel Ogunjo ,&nbsp;Joshua Akinsusi ,&nbsp;Babatunde Rabiu ,&nbsp;Ibiyinka Fuwape","doi":"10.1016/j.jastp.2024.106380","DOIUrl":"10.1016/j.jastp.2024.106380","url":null,"abstract":"<div><div>Activities in geospace occur at different time scales. Understanding geomagnetic activity at high temporal scales will give insight into fast dynamics in geospace. This study aims to investigate dynamical complexities in geomagnetic activities at a high temporal scale across three solar cycles. Geomagnetic activities, as represented by 5-min SYM-H data, were considered in this study over three solar cycles (22–24) from 1986 to 2019. Chaos analysis using sample entropy, Lyapunov exponent, and correlation dimension indicates that the geomagnetic activities are driven by intrinsic complex and chaotic processes. Positive Lyapunov exponent values between 0.13 and 0.18, 0.15–0.18, and 0.16–0.19 were obtained for solar cycles 22, 23, and 24 respectively. Furthermore, geomagnetic activities were also found to have multifractal structures driven by high fractal exponents with fine structures. A positive relationship was obtained between the annual mean values of SYM-H and the degree of complexity. It is concluded that geomagnetic activities have a short prediction horizon.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"265 ","pages":"Article 106380"},"PeriodicalIF":1.8,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531337","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}