Comparative Assessment of Solar and Geophysical Parameters During the Initial Six Years of Solar Cycles 24 and 25

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The analysis focuses on key solar and geophysical parameters, including sunspot numbers, halo coronal mass ejections (CMEs), solar radio flux at 10.7 cm (F10.7), and geomagnetic storms, to assess differences in solar behavior between the two cycles. Sunspot numbers varied between 0 and 139.1 in Solar Cycle 24, whereas they ranged from 0.2 to 216 during the corresponding period of Solar Cycle 25. Similarly, the F10.7 cm radio flux fluctuated between 65.7 and 153.5 s.f.u. during 2008–2013, and between 67.05 and 245.6 s.f.u. from 2019 to 2024, reflecting an overall increase in solar output. The study also includes an analysis of halo CMEs, with 192 events observed during Solar Cycle 24 and 227 during Solar Cycle 25, both characterized by an angular width of 360°. Geomagnetic activity was assessed using 104 events from Cycle 24 and 179 from Cycle 25, with Disturbance Storm Time (Dst) index values ranging from –50 to –350 nT. The results indicate a significant increase in solar activity during the early phase of Solar Cycle 25 compared to Solar Cycle 24. This suggests a more intense and dynamic space weather environment in the current solar cycle, which may have important implications for space weather forecasting and satellite operations. Solar Cycle F10.7 cm radio flux Sunspot Number Coronal Mass Ejection (CME) Geomagnetic Storm Solar indices Figures Figure 1 Figure 2 Figure 3 1. Introduction In the last few decades, effects of space weather (Singh et al. 2010 ) and solar activity (Loehle et al. 2010; Siingh et al. 2011 ) have garnered increasing attention due to their far-reaching implications for Earth's climate systems and technological infrastructure (Haigh 1996 ; Siingh et al. 2001). Here, space weather refers to the dynamic conditions in the near-Earth space environment, mostly controlled by solar phenomena such as solar flares, coronal mass ejections (CMEs), and high-speed solar wind streams (Singh et al. 2010 ). These events can disturb the Earth's magnetosphere and ionosphere (Fiedorov et al. 2021), leading to geomagnetic storms that affect satellite operations, radio communications, and navigation systems (Siingh et al. 2001; Nitta et al. 2021). Central to space weather is the study of solar activity, which mainly depends on the Sun’s magnetic field and its variation in both space and time, plasma emissions, and radiation output. Solar activity is identified through a temporary patchy darker region on the Sun’s outer surface called the photosphere. These darker regions are called sunspots, appearing darker due to their lower temperatures and associated with intense magnetic activity (Borrero and Ichimoto 2011 ; Livingston and Watson 2015 ). These sunspots serve as a proxy for broader solar phenomena, as they are often the sites of energetic solar flares and the origins of CMEs (Falco et al. 2019 ; Nitta et al. 2021). The solar cycle, also known as the sunspot cycle, is a quasi-periodic oscillation in solar magnetic activity, with an average duration of approximately 11 years (Friis-Christensen and Lassen 1991). It is characterized by the waxing and waning of sunspot numbers, transitioning between two key phases: the solar minimum, marked by minimal sunspot activity and relatively calm space weather conditions, and the solar maximum, during which sunspot numbers peak and the frequency of solar events increases significantly (Wilson 2006 ). The solar cycle profoundly influences space weather patterns and modulates the amount of solar irradiance received by Earth, which in turn affects atmospheric chemistry and climate variability (Friis-Christensen and Lassen 1991; Svalgaard and Cliver 2005 ). Solar Cycle 24, which officially concluded in 2018, has been extensively studied due to its unusually low levels of activity compared to previous cycles (De Jager and Duhau 2009 ; Agee et al. 2010 ; Russell et al. 2021; Singh et al. 2014 ). The solar minimum occurred around 2008–2009, characterized by an extended period of low sunspot counts and weak solar wind, while the solar maximum was observed around 2011 to 2013, marked by a modest peak in sunspot numbers and associated solar events. The subdued nature of Solar Cycle 24 has sparked interest in understanding long-term solar variability and its implications for future space weather forecasting and climate modeling. Solar Cycle 25, which began in December 2019 following a solar minimum that extended through much of 2018 and 2019, is currently ongoing and has garnered significant attention due to its stronger-than-expected rise in activity. Early forecasts predicted a cycle similar in strength to the relatively weak Solar Cycle 24, but recent observations have shown a more rapid increase in sunspot numbers and solar flare occurrences than initially anticipated (Pishkalo and Vasiljeva 2023 ; Aparicio et al. 2023 ). The F10.7 cm index, first introduced in 1947, has since become a key proxy for solar extreme ultraviolet (EUV) output and is widely used in modeling Earth's upper atmosphere, including thermospheric density and ionospheric variability (Tapping 2013 ). Its measurements, unaffected by terrestrial weather and taken daily from ground-based observatories, offer a consistent long-term record of solar activity. The F10.7 flux responds to enhanced magnetic activity, such as active regions and flares, and closely tracks changes in solar EUV radiation, making it invaluable for space weather forecasting and satellite drag estimation. Studies have demonstrated a particularly high correlation (R > 0.95) between the F10.7 index and sunspot number during periods of moderate to high solar activity, reinforcing its utility as a robust indicator across solar cycles (Dudok de Wit et al. 2014). Another significant solar phenomenon is the coronal mass ejection (CME), particularly halo CMEs, which appear to envelop the Sun in coronagraph images as they propagate toward Earth. Although halo CMEs account for only about 4% of all CMEs, they tend to be faster and more geoeffective. This distinction often reflects observational biases rather than intrinsic physical differences (Gopalswamy et al. 2010 ; Sugiura and Kamei 1991 ). Halo CMEs are typically Earth-directed. Hess and Zhang (2017) identified 70 such interplanetary CMEs during Solar Cycle 24 using in situ data from NASA’s ACE spacecraft. Their statistical analysis highlighted key properties, including source regions, geoeffectiveness, and associated flare strength. Notably, they observed a hemispheric shift in CME origins during Solar Cycle 24—from the northern hemisphere in the early cycle to the southern hemisphere after April 2012—mirroring the evolving solar magnetic asymmetry. Geomagnetic storms, which are major disruptions in the Earth’s magnetosphere, are driven by solar activity, including CMEs and high-speed solar wind streams. The Disturbance Storm Time (Dst) index measures geomagnetic activity, with different storm intensities categorized as moderate (− 50 to − 100 nT), strong (− 100 to − 200 nT), severe (− 200 to − 350 nT), and great (below − 350 nT) (Gonzalez et al. 1994 ; Kuznetsov et al. 1998 ). These storms are caused by interplanetary shock waves and solar wind disruptions (Cane et al. 1978). This study includes geomagnetic storm data from 2008 to 2013 and from 2019 to 2024. While past studies have examined individual aspects of solar activity (e.g., sunspots, CMEs, geomagnetic storms, F10.7 cm index) during specific solar cycles (Svalgaard and Cliver 2005 ; Hess and Zhang 2017; Maurya et al. 2018; Dudok de Wit et al. 2014), there is limited comparative analysis between Solar Cycles 24 and 25. To fill this gap, this paper presents a comparative analysis of solar and geomagnetic conditions during the first six years of Solar Cycle 24 (2008–2013) and the initial years of Solar Cycle 25 (2019–2024). Specifically, we compare the number of sunspots, the F10.7 cm index, and the occurrence of halo CMEs, including 227 cases observed between 2019 and 2024 and 177 cases observed between 2008 and 2013. Additionally, we examine 179 instances of geomagnetic storms that occurred between 2019 and 2024, compared to 104 instances recorded between 2008 and 2013. 2. Data sources and solar activity parameters 2.1 Sunspot Number A sunspot is the darkest region on the sun's surface, with a powerful magnetic field that vanishes as the surrounding area becomes less bright. The variation of sunspot numbers for the years 2008–2013 and 2019–2024 is displayed in Fig. 1 . The Space Weather Prediction Centre's Solar Cycle Progression website, which can be found at Solar Cycle Development | NWS/NOAA Space Weather Prediction Centre, provided the data for sunspot numbers using link https://www.sidc.be/SILSO/datafiles . 2.2 Solar radio flux F10.7cm With a wavelength of 10.7 cm (corresponding to a frequency of 2800 MHz), the F10.7 cm index is a measurement of solar radio flux per unit frequency. This value is commonly presented in “solar flux units” (s.f.u.), where 1 s.f.u. = 10⁻²² W/m²/Hz. The F10.7 cm index, is a key proxy for solar extreme ultraviolet (EUV) radiation. The F10.7 cm index typically ranges from about 67 s.f.u. during quiet Sun conditions to over 300 s.f.u. during periods of high solar activity, such as strong solar flares. Measurements are taken three times daily, at 1700, 2000, and 2300 UTC. The F10.7 cm index provides valuable information about solar activity and also serves as an indicator of conditions in the lower solar corona. The data for the F10.7 cm index presented here was sourced from the Solar Cycle Progression page maintained by the NOAA / NWS Space Weather Prediction Center using link https://spaceweather.gc.ca/forecast-prevision/solar-solaire/solarflux/sx-5-en.php . Figure 2 illustrates the annual F10.7 cm index values for the periods 2008–2013 and 2019–2024. 2.3 Halo CMEs Large structures with magnetic and plasma fields that are ejected are referred to as coronal mass ejections, or CMEs, from the Sun into the heliosphere. CMEs that happen near the Since solar disk canters are probably going to have a direct effect on Earth, they could help forecast geomagnetic storms. Halo CMEs are a subset of front-side CMEs, characterized by The Sun being surrounded by a "halo" of high coronal emission (Loewe & Prölss, 1997 ). They appear to encircle and rapidly enlarge The observing coronagraph's occulting disk. Halo CMEs were frequently spotted by the Large Angle and Spectrometric Coronagraph (LASCO) of the Solar and Heliosphere Observatory (SOHO) mission (Dere et al., 1999 ). In this paper, we have only looked at 360◦ wide halo CMEs. The Halo CME data has been hosted on the website https://cdaw.gsfc.nasa.gov/CME_list/halo/halo.html . Table 1 Shows the number of halo CMEs observed in each year between 2008 and 2013, as well as 2019 and 2024. A comparison of the halo CMEs seen in 2008–2013 and 2019–2024 was displayed in Fig. 3. Table 1 Number of halo coronal mass ejections (CMEs) observed during the periods 2008–2013 (Solar Cycle 24) and 2019–2024 (Solar Cycle 25) The quantity of Halo CMEs Solar Cycle 24 (2008–2013) 2008 2009 2010 2011 2012 2013 1 1 11 41 84 55 Solar Cycle 25 (2019–2024) 2019 2020 2021 2022 2023 2024 1 4 16 44 81 101 2.4 Geomagnetic storm A geomagnetic storm occurs when the magnetic field and solar wind of Earth interact more intensely, disrupting the magnetosphere. High-speed solar wind streamers (HSS) and coronal mass ejections (CMEs) are its main energy sources. We used huge, severe, strong, and moderate storms in our investigation, and the information was sourced from the Geomagnetic Equatorial Dst Index Home Page, the website of the World Data Centre ( https://wdc.kugi.kyoto-u.ac.jp/ ). The storm events that were observed in 2008–2013 and 2019–2024 are listed year-by-year in Table 2 . The specifics of the variance in different storm caused by geomagnetic categories are displayed in Fig. 4 . Table 2 Number of geomagnetic storms categorized by intensity—moderate, strong, severe, and great—recorded during the periods 2008–2013 (Solar Cycle 24) and 2019–2024 (Solar Cycle 25). Year Moderate Strong Severe Great Solar Cycle 24 (2008–2013) 2008 03 Nil Nil Nil 2009 Nil Nil Nil Nil 2010 11 Nil Nil Nil 2011 29 03 Nil Nil 2012 25 07 Nil Nil 2013 24 02 Nil Nil Solar Cycle 25 (2019–2024) 2019 08 Nil Nil Nil 2020 06 Nil Nil Nil 2021 11 1 Nil Nil 2022 30 2 1 Nil 2023 40 10 1 Nil 2024 50 16 3 Nil 3. Results and Discussion Throughout its approximately 11-year Schwabe cycle, the Sun’s activity undergoes remarkable modulation. While the total solar irradiance (TSI) fluctuates modestly—around ± 0.1% peak-to-peak—the ultraviolet (UV) and X-ray bands show much larger variations. Specifically, spectral solar irradiance in the UV (e.g., 200–300 nm) can vary by 50–100% over a cycle, with Ly-α (121.6 nm) oscillating by tens of percent, and EUV (10–120 nm) by a factor of ~ 2× (Krivova et al. 2006 ). In contrast, X-ray irradiance—particularly the soft X-ray (0.1–0.8 nm) background measured by GOES—can change by 10–100 times between solar minimum and maximum (Bruevich and Yakunina 2019 ; Rycroft 2013 ). Analysis of the 11-year solar activity cycle using long-term sunspot records reveals a strong correlation between solar activity and geomagnetic phenomena, highlighting the critical dependence of geomagnetic research on solar variability (Siingh et al. 2011 ). Figure 1 displays the monthly variation in sunspot numbers. Specifically, Fig. 1 (a) illustrates the monthly fluctuation during the 2008–2013 period, representing the first half of Solar Cycle 24. During this time, the sunspot number varied from 0 to 139.1, encompassing both the solar minimum and maximum phases. The minimum phase occurred around 2008–2009, while the maximum was recorded between 2012 and 2013. Solar Cycle 25, which spans approximately from 2018 to 2024, also includes distinct solar minimum and maximum phases within this timeframe. As shown in Fig. 1 (b), the sunspot number during this cycle ranged from 0.2 to 216, with the highest peak observed in this period. The minimum phase of Solar Cycle 25 occurred around 2019–2021, followed by the maximum phase between 2022 and 2024. Based on the sunspot number data, it is reasonable to conclude that Solar Cycle 25 has exhibited higher overall solar activity compared to Solar Cycle 24. Bhowmik and Nandy ( 2018 ) and other dynamo-based models predicted that Cycle 25 would be stronger than Cycle 24, estimating peak sunspot numbers up to ~ 168 ± 16. Similarly, Bisoi et al. ( 2020 ), using heliospheric magnetic field data, also forecasted a stronger Cycle 25 compared to Cycle 24. The current results further confirm the findings of these previous works. The change in F10.7 cm, a widely used proxy for solar activity, is shown in Fig. 2 . Figures 2 (a) and 2(b) depict solar radio flux variations during the intervals 2008–2013 (Solar Cycle 24) and 2019–2024 (Solar Cycle 25), respectively. In 2008–2013, F10.7 ranged from 65.7 to 153.5 s.f.u., while in 2019–2024 it spanned 67 to 245 s.f.u. These findings confirm that Solar Cycle 25 exhibits significantly stronger peak radio flux than Cycle 24. This contrast aligns with prior studies: Tapping ( 2013 ) reported an average peak F10.7 of approximately 190 ± 35 s.f.u. across cycles since 1950, with the top 15 daily values averaging ~ 350 ± 12 s.f.u., and noted that Cycle 24 peaked at ~ 125 ± 20 s.f.u.—substantially lower than the historical mean (Chin et al. 2011; Pesnel 2020). Conversely, our observed 245 s.f.u. peak during Cycle 25 falls well within the expected range, marking a return toward higher solar activity levels. Moreover, comparative analyses of early-cycle behavior demonstrate that Cycle 24's F10.7 levels (65–190 s.f.u. during 2008–2013) were below those of Cycle 23 (65–283 s.f.u. during 1996–2001) (Singh and Tonk 2014 ). This further underscores the relative weakness of Cycle 24 compared to its predecessors. In contrast, the elevated and sustained F10.7 values in Cycle 25 signify a clear resurgence in solar activity. Additionally, Qian and Mursula ( 2025 ) highlighted that while F10.7 remains a useful long-term proxy, recent saturation effects may cause slight overestimation of thermospheric energy input; nonetheless, F10.7 continues to serve as a robust indicator during solar maxima. Figure 2 also marks the timing of solar minima and maxima based on the observed F10.7 flux, clearly illustrating that Solar Cycle 25's peak is both higher and broader compared to Cycle 24. Table 1 presents the number of halo CMEs observed annually between 2008–2013 and 2019–2024. Figure 3 illustrates the variation in the occurrence of halo CMEs (with angular width = 360°) during these two time periods. A total of 192 halo CMEs were recorded from 2008 to 2013, whereas 227 were observed between 2019 and 2024. This increase in halo CME events suggests heightened solar activity during the latter period. This trend aligns with broader statistical patterns. Gopalswamy et al. ( 2015 ) found that Cycle 24, despite a ~ 40% decline in sunspot number compared to Cycle 23, exhibited a similar or slightly higher abundance of halo CMEs—attributed to anomalous CME expansion under weakened heliospheric pressure. Dagnew et al. ( 2020 ), focusing on Cycles 23 and 24, also reported a 44% higher halo CME rate per sunspot in Cycle 24. These studies suggest that reduced ambient pressure allowed more CMEs to achieve full halo status without necessarily increasing eruption energy or speed. Early evidence from Cycle 25 supports this emerging pattern. Gopalswamy et al. ( 2024 ) noted that Cycle 25’s halo CME occurrence—normalized by sunspot number—remains comparable to Cycle 24, both exceeding Cycle 23 levels. They concluded that Cycle 25 mirrors or modestly surpasses Cycle 24 in halo frequency, once again tied to the low solar wind pressure conditions. Therefore, not only do our observations (192 vs. 227 halo CMEs) reflect elevated solar activity in Cycle 25, but they also corroborate peer-reviewed analyses attributing this increase to both intrinsic cycle strength and ambient heliospheric conditions. The larger halo CME count in 2019–2024 thus substantiates the conclusion that Solar Cycle 25 represents a renewed phase of enhanced eruptive activity following the subdued Cycle 24. Table 2 presents the number of geomagnetic storms categorized by intensity—moderate, strong, severe, and great—recorded annually between 2008–2013 (Solar Cycle 24) and 2019–2024 (Solar Cycle 25). During 2008–2013, a total of 92 moderate storms and 12 strong storms were observed, with no severe or great storms reported. In contrast, from 2019 to 2024, geomagnetic activity intensified: 145 moderate storms, 29 strong storms, and 5 severe storms were recorded. Notably, no geomagnetic storms occurred in 2019, which corresponds with the solar minimum at the start of Cycle 25. Figure 4 illustrates the distribution of geomagnetic storm categories across the two periods. As shown in Fig. 4 (a), there was a significant increase in powerful geomagnetic storms (strong and severe) during 2019–2024, compared to Fig. 4 (b), which depicts the relatively quiet period of 2008–2013. The presence of five severe storms in Solar Cycle 25, and none in Cycle 24, further reinforces the observed difference in solar and geomagnetic activity levels between the two cycles. This increase in geomagnetic storm activity correlates with the higher frequency of halo CMEs during 2019–2024. Previous studies have established a strong connection between halo CMEs and intense geomagnetic storms (Gopalswamy et al. 2007 ), as halo CMEs—especially Earth-directed ones—are often responsible for severe space weather events. Therefore, the lower number of halo CMEs recorded between 2008–2013 likely contributed to the reduced geomagnetic activity in that period. Taken together with the data presented in Fig. 2 , these findings support the conclusion that Solar Cycle 24 exhibited significantly lower solar and geomagnetic activity compared to Solar Cycle 25. This difference is consistent with recent studies suggesting that the ambient heliospheric conditions and CME characteristics in Cycle 25 are more conducive to triggering geoeffective events (Kilpua et al. 2017 ; Gopalswamy et al. 2024 ). 4. Summary and Conclusions This study presents a comprehensive comparative analysis of five key solar and geomagnetic parameters: sunspot number, F10.7 cm radio flux index, halo coronal mass ejections (CMEs), and geomagnetic storm frequency and intensity during the early and peak phases of Solar Cycles 24 and 25. While prior studies have explored these variables as case study for individual parameters for individual cycles, a direct comparison between Cycles 24 and 25 has remained relatively unexplored. This work addresses that gap by evaluating the first six years of Solar Cycle 24 (2008–2013) alongside the corresponding period of Solar Cycle 25 (2019–2024). The key findings of this comparative analysis are summarized as follows: Monthly sunspot numbers ranged from 0.2 to 216 during Solar Cycle 25 and from 0 to 139.1 during Solar Cycle 24. The greater maximum and broader distribution in Cycle 25 suggest enhanced solar magnetic activity relative to Cycle 24. Both solar cycles began with anomalously quiet conditions, as evidenced by the near absence of sunspots during 2008–2009 and 2019–2020. Such deep and prolonged minima have not been observed in nearly a century, emphasizing the unusual onset of both cycles. The solar radio flux F10.7 cm index ranged from 65.7 to 153.5 s.f.u. in Cycle 24, compared to 67 to 245 s.f.u. in Cycle 25. This substantial increase in peak values during Cycle 25 indicates stronger emissions from active solar regions, consistent with heightened solar EUV and X-ray output. A total of 192 halo CMEs was reported between 2008 and 2013, while 227 events occurred from 2019 to 2024. The increase in Earth-directed CME events further supports the conclusion of greater eruptive activity during Cycle 25. From 2019 to 2024, 179 geomagnetic storms were observed, including 145 moderate, 29 strong, and 5 severe events. This contrasts with 104 storms in Cycle 24 (92 moderate, 12 strong), confirming enhanced geomagnetic disturbances during Cycle 25, likely driven by more frequent and energetic CMEs. Overall, these results demonstrate that Solar Cycle 25 has so far exhibited stronger and more sustained solar and geomagnetic activity than Solar Cycle 24. This has significant implications for space weather forecasting and the understanding of long-term solar variability. Future work should focus on extending this comparison through the declining phase of Cycle 25 and examining associated impacts on the near-Earth space environment. Declarations The authors declare no competing interests. Author Contribution AK analyzed various data and wrote the initial draft. DB helped analyze F10.7 flux data. The AKM conceptualized the idea, supervised the analysis, and modified the draft. UP helped write, review, and edit the manuscript. Acknowledgements: AKM thanks to Anusandhan National Research Foundation (ANRF), New Delhi, India for the CORE research grant (CRG/2021/001322) which supported this work Data Availability The datasets generated and analyzed during the current study are available from the corresponding websites: https://www.sidc.be/SILSO/datafiles; https://spaceweather.gc.ca/forecast-prevision/solar-solaire/solarflux/sx-5-en.php; https://cdaw.gsfc.nasa.gov/CME_list/halo/halo.html; https://wdc.kugi.kyoto-u.ac.jp/ References Agee, E. 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Menvielle (Eds.), IAGA Bulletin , 40. ISGI Publ. Off., Saint. Maur-des-Fosses, France. Svalgaard, L., & Cliver, E. W. (2005). The Role of the Solar Cycle in Space Weather. Solar Physics , 227(1–2), 125–140. https://doi.org/10.1007/s11207-005-0851-9 Tapping, K. F. (2013). The 10.7 cm solar radio flux (F10.7). Space Weather , 11(7), 394–406. https://doi.org/10.1002/swe.20064 Wilson, R. M. (2006). Long-term Variability in the Length of the Solar Cycle. Astrophysical Journal , 132, 1058–1070. Zhelavskaya, I. L., & Bakhmetyeva, T. S. (2021). Space weather consequences during solar cycle maxima: The role of F10.7 in ionospheric and thermospheric variations. Advances in Space Research , 68(9), 2974–2986. https://doi.org/10.1016/j.asr.2021.07.034 Qian, L., & Mursula, K. (2025). Evaluating F10.7 and F30 radio fluxes as long-term solar proxies of energy deposition in the thermosphere. Annales Geophysicae , 43, 175–182. https://doi.org/10.5194/angeo-43-175-2025 Bisoi, S. K., Janardhan, P., & Ananthakrishnan, S. (2020). Another Mini Solar Maximum in the Offing: A Prediction for the Amplitude of Solar Cycle 25. Journal of Geophysical Research: Space Physics , 125(7). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6996698","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":478076272,"identity":"e1744df2-40cb-4f9e-a073-23b6f19f29b3","order_by":0,"name":"Angel Kujur","email":"","orcid":"","institution":"Babasaheb Bhimrao Ambedkar University","correspondingAuthor":false,"prefix":"","firstName":"Angel","middleName":"","lastName":"Kujur","suffix":""},{"id":478076274,"identity":"4c6907ea-ecae-4c3c-b0b1-bb8ce2665f8f","order_by":1,"name":"Dayanand Bhaskar","email":"","orcid":"","institution":"Babasaheb Bhimrao Ambedkar University","correspondingAuthor":false,"prefix":"","firstName":"Dayanand","middleName":"","lastName":"Bhaskar","suffix":""},{"id":478076275,"identity":"26b25940-7782-4802-ad4c-93daa5d010b4","order_by":2,"name":"Uma Pandey","email":"","orcid":"","institution":"Indian Institute of Technology","correspondingAuthor":false,"prefix":"","firstName":"Uma","middleName":"","lastName":"Pandey","suffix":""},{"id":478076277,"identity":"eb7656b9-39ea-4c49-9a3b-51abe75fa722","order_by":3,"name":"Ajeet Kumar Maurya","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2klEQVRIiWNgGAWjYFCCAyBCgoeBvQFIG1gQqeUASAsPSK+BBEkWJYBJwqr5Gw8ffPyBwUJGPvL51Q0/CiQY+Nu7E/BqkThwLNkA5DDD2zllN3uADpM4c3YDAUedMZMAa5mdk3aDB6jFQCIXvxb5A+e//wBrmXkm7eYfYrQYHDjDBg4xeQn2Y7eJssXwwDFjiTMGEjwGPDlst2WADIJ+kbtx+OGHioo6e/n2489uvvljI8ff3kvA+0C/A50HciGPAYjPg185CPA3QGj5BvYHhFWPglEwCkbBiAQA9OdIgNkz5UAAAAAASUVORK5CYII=","orcid":"","institution":"Babasaheb Bhimrao Ambedkar University","correspondingAuthor":true,"prefix":"","firstName":"Ajeet","middleName":"Kumar","lastName":"Maurya","suffix":""}],"badges":[],"createdAt":"2025-06-28 09:08:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6996698/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6996698/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":85858708,"identity":"b9f029f2-b65f-48bd-8b35-bc6a766a25f4","added_by":"auto","created_at":"2025-07-02 11:56:44","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":46077,"visible":true,"origin":"","legend":"\u003cp\u003eAverage monthly variations in Sunspot Number observed during the early phases of two solar cycles: (a) Solar Cycle 24 (2008–2013) and (b) Solar Cycle 25 (2019–2024).\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6996698/v1/5136a6636a8c6672294cc68c.jpg"},{"id":85858706,"identity":"df48adf1-b9b2-4cc8-a750-0faa6cf4c8a9","added_by":"auto","created_at":"2025-07-02 11:56:44","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":46565,"visible":true,"origin":"","legend":"\u003cp\u003eVariations in solar radio flux (F10.7 cm) observed during the initial phases of two solar cycles: (a) Solar Cycle 24 (2008–2013) and (b) Solar Cycle 25 (2019–2024).\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6996698/v1/f7cb11c058c4ef68ac390f08.jpg"},{"id":85858707,"identity":"f16f1364-e334-4202-82f4-11dbce8229f1","added_by":"auto","created_at":"2025-07-02 11:56:44","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":32714,"visible":true,"origin":"","legend":"\u003cp\u003eNumber of halo coronal mass ejections (CMEs) observed during the early phases of Solar Cycle 24 and Solar Cycle 25: (a) 2008–2013 and (b) 2019–2024.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6996698/v1/afa92d8fb700c6b7be2b3d32.jpg"},{"id":90416275,"identity":"ce8cc328-031a-4e42-adce-caa760b2e04b","added_by":"auto","created_at":"2025-09-02 13:17:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":664981,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6996698/v1/42276d09-6474-448e-aa16-5d6bb8ea34e8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparative Assessment of Solar and Geophysical Parameters During the Initial Six Years of Solar Cycles 24 and 25","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eIn the last few decades, effects of space weather (Singh et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2010\u003c/span\u003e) and solar activity (Loehle et al. 2010; Siingh et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) have garnered increasing attention due to their far-reaching implications for Earth's climate systems and technological infrastructure (Haigh \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Siingh et al. 2001). Here, space weather refers to the dynamic conditions in the near-Earth space environment, mostly controlled by solar phenomena such as solar flares, coronal mass ejections (CMEs), and high-speed solar wind streams (Singh et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). These events can disturb the Earth's magnetosphere and ionosphere (Fiedorov et al. 2021), leading to geomagnetic storms that affect satellite operations, radio communications, and navigation systems (Siingh et al. 2001; Nitta et al. 2021).\u003c/p\u003e \u003cp\u003eCentral to space weather is the study of solar activity, which mainly depends on the Sun\u0026rsquo;s magnetic field and its variation in both space and time, plasma emissions, and radiation output. Solar activity is identified through a temporary patchy darker region on the Sun\u0026rsquo;s outer surface called the photosphere. These darker regions are called sunspots, appearing darker due to their lower temperatures and associated with intense magnetic activity (Borrero and Ichimoto \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Livingston and Watson \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). These sunspots serve as a proxy for broader solar phenomena, as they are often the sites of energetic solar flares and the origins of CMEs (Falco et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Nitta et al. 2021).\u003c/p\u003e \u003cp\u003eThe solar cycle, also known as the sunspot cycle, is a quasi-periodic oscillation in solar magnetic activity, with an average duration of approximately 11 years (Friis-Christensen and Lassen 1991). It is characterized by the waxing and waning of sunspot numbers, transitioning between two key phases: the solar minimum, marked by minimal sunspot activity and relatively calm space weather conditions, and the solar maximum, during which sunspot numbers peak and the frequency of solar events increases significantly (Wilson \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). The solar cycle profoundly influences space weather patterns and modulates the amount of solar irradiance received by Earth, which in turn affects atmospheric chemistry and climate variability (Friis-Christensen and Lassen 1991; Svalgaard and Cliver \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2005\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSolar Cycle 24, which officially concluded in 2018, has been extensively studied due to its unusually low levels of activity compared to previous cycles (De Jager and Duhau \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Agee et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Russell et al. 2021; Singh et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). The solar minimum occurred around 2008\u0026ndash;2009, characterized by an extended period of low sunspot counts and weak solar wind, while the solar maximum was observed around 2011 to 2013, marked by a modest peak in sunspot numbers and associated solar events. The subdued nature of Solar Cycle 24 has sparked interest in understanding long-term solar variability and its implications for future space weather forecasting and climate modeling. Solar Cycle 25, which began in December 2019 following a solar minimum that extended through much of 2018 and 2019, is currently ongoing and has garnered significant attention due to its stronger-than-expected rise in activity. Early forecasts predicted a cycle similar in strength to the relatively weak Solar Cycle 24, but recent observations have shown a more rapid increase in sunspot numbers and solar flare occurrences than initially anticipated (Pishkalo and Vasiljeva \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Aparicio et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe F10.7 cm index, first introduced in 1947, has since become a key proxy for solar extreme ultraviolet (EUV) output and is widely used in modeling Earth's upper atmosphere, including thermospheric density and ionospheric variability (Tapping \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Its measurements, unaffected by terrestrial weather and taken daily from ground-based observatories, offer a consistent long-term record of solar activity. The F10.7 flux responds to enhanced magnetic activity, such as active regions and flares, and closely tracks changes in solar EUV radiation, making it invaluable for space weather forecasting and satellite drag estimation. Studies have demonstrated a particularly high correlation (R\u0026thinsp;\u0026gt;\u0026thinsp;0.95) between the F10.7 index and sunspot number during periods of moderate to high solar activity, reinforcing its utility as a robust indicator across solar cycles (Dudok de Wit et al. 2014).\u003c/p\u003e \u003cp\u003eAnother significant solar phenomenon is the coronal mass ejection (CME), particularly halo CMEs, which appear to envelop the Sun in coronagraph images as they propagate toward Earth. Although halo CMEs account for only about 4% of all CMEs, they tend to be faster and more geoeffective. This distinction often reflects observational biases rather than intrinsic physical differences (Gopalswamy et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Sugiura and Kamei \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e1991\u003c/span\u003e). Halo CMEs are typically Earth-directed. Hess and Zhang (2017) identified 70 such interplanetary CMEs during Solar Cycle 24 using in situ data from NASA\u0026rsquo;s ACE spacecraft. Their statistical analysis highlighted key properties, including source regions, geoeffectiveness, and associated flare strength. Notably, they observed a hemispheric shift in CME origins during Solar Cycle 24\u0026mdash;from the northern hemisphere in the early cycle to the southern hemisphere after April 2012\u0026mdash;mirroring the evolving solar magnetic asymmetry.\u003c/p\u003e \u003cp\u003eGeomagnetic storms, which are major disruptions in the Earth\u0026rsquo;s magnetosphere, are driven by solar activity, including CMEs and high-speed solar wind streams. The Disturbance Storm Time (Dst) index measures geomagnetic activity, with different storm intensities categorized as moderate (\u0026minus;\u0026thinsp;50 to \u0026minus;\u0026thinsp;100 nT), strong (\u0026minus;\u0026thinsp;100 to \u0026minus;\u0026thinsp;200 nT), severe (\u0026minus;\u0026thinsp;200 to \u0026minus;\u0026thinsp;350 nT), and great (below \u0026minus;\u0026thinsp;350 nT) (Gonzalez et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Kuznetsov et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). These storms are caused by interplanetary shock waves and solar wind disruptions (Cane et al. 1978). This study includes geomagnetic storm data from 2008 to 2013 and from 2019 to 2024.\u003c/p\u003e \u003cp\u003eWhile past studies have examined individual aspects of solar activity (e.g., sunspots, CMEs, geomagnetic storms, F10.7 cm index) during specific solar cycles (Svalgaard and Cliver \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Hess and Zhang 2017; Maurya et al. 2018; Dudok de Wit et al. 2014), there is limited comparative analysis between Solar Cycles 24 and 25. To fill this gap, this paper presents a comparative analysis of solar and geomagnetic conditions during the first six years of Solar Cycle 24 (2008\u0026ndash;2013) and the initial years of Solar Cycle 25 (2019\u0026ndash;2024). Specifically, we compare the number of sunspots, the F10.7 cm index, and the occurrence of halo CMEs, including 227 cases observed between 2019 and 2024 and 177 cases observed between 2008 and 2013. Additionally, we examine 179 instances of geomagnetic storms that occurred between 2019 and 2024, compared to 104 instances recorded between 2008 and 2013.\u003c/p\u003e"},{"header":"2. Data sources and solar activity parameters","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.1 Sunspot Number\u003c/h2\u003e\n \u003cp\u003eA sunspot is the darkest region on the sun\u0026apos;s surface, with a powerful magnetic field that vanishes as the surrounding area becomes less bright. The variation of sunspot numbers for the years 2008\u0026ndash;2013 and 2019\u0026ndash;2024 is displayed in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. The Space Weather Prediction Centre\u0026apos;s Solar Cycle Progression website, which can be found at Solar Cycle Development | NWS/NOAA Space Weather Prediction Centre, provided the data for sunspot numbers using link \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.sidc.be/SILSO/datafiles\u003c/span\u003e\u003c/span\u003e.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.2 Solar radio flux F10.7cm\u003c/h2\u003e\n \u003cp\u003eWith a wavelength of 10.7 cm (corresponding to a frequency of 2800 MHz), the F10.7 cm index is a measurement of solar radio flux per unit frequency. This value is commonly presented in \u0026ldquo;solar flux units\u0026rdquo; (s.f.u.), where 1 s.f.u. = 10⁻\u0026sup2;\u0026sup2; W/m\u0026sup2;/Hz. The F10.7 cm index, is a key proxy for solar extreme ultraviolet (EUV) radiation. The F10.7 cm index typically ranges from about 67 s.f.u. during quiet Sun conditions to over 300 s.f.u. during periods of high solar activity, such as strong solar flares. Measurements are taken three times daily, at 1700, 2000, and 2300 UTC. The F10.7 cm index provides valuable information about solar activity and also serves as an indicator of conditions in the lower solar corona.\u003c/p\u003e\n \u003cp\u003eThe data for the F10.7 cm index presented here was sourced from the Solar Cycle Progression page maintained by the NOAA / NWS Space Weather Prediction Center using link \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://spaceweather.gc.ca/forecast-prevision/solar-solaire/solarflux/sx-5-en.php\u003c/span\u003e\u003c/span\u003e. Figure \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e illustrates the annual F10.7 cm index values for the periods 2008\u0026ndash;2013 and 2019\u0026ndash;2024.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e2.3 Halo CMEs\u003c/h2\u003e\n \u003cp\u003eLarge structures with magnetic and plasma fields that are ejected are referred to as coronal mass ejections, or CMEs, from the Sun into the heliosphere. CMEs that happen near the Since solar disk canters are probably going to have a direct effect on Earth, they could help forecast geomagnetic storms. Halo CMEs are a subset of front-side CMEs, characterized by The Sun being surrounded by a \u0026quot;halo\u0026quot; of high coronal emission (Loewe \u0026amp; Pr\u0026ouml;lss, \u003cspan class=\"CitationRef\"\u003e1997\u003c/span\u003e). They appear to encircle and rapidly enlarge The observing coronagraph\u0026apos;s occulting disk. Halo CMEs were frequently spotted by the Large Angle and Spectrometric Coronagraph (LASCO) of the Solar and Heliosphere Observatory (SOHO) mission (Dere et al., \u003cspan class=\"CitationRef\"\u003e1999\u003c/span\u003e). In this paper, we have only looked at 360◦ wide halo CMEs. The Halo CME data has been hosted on the website \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://cdaw.gsfc.nasa.gov/CME_list/halo/halo.html\u003c/span\u003e\u003c/span\u003e. Table\u0026nbsp;1 Shows the number of halo CMEs observed in each year between 2008 and 2013, as well as 2019 and 2024. A comparison of the halo CMEs seen in 2008\u0026ndash;2013 and 2019\u0026ndash;2024 was displayed in Fig.\u0026nbsp;3.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eTable 1\u0026nbsp;\u003c/strong\u003eNumber of halo coronal mass ejections (CMEs) observed during the periods 2008\u0026ndash;2013 (Solar Cycle 24) and 2019\u0026ndash;2024 (Solar Cycle 25)\u003c/p\u003e\n \u003cp\u003eThe quantity of Halo CMEs\u003c/p\u003e\n \u003cp\u003eSolar Cycle 24 (2008\u0026ndash;2013)\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable id=\"Taba\" border=\"1\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2008\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2009\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2010\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2011\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2012\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2013\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e84\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eSolar Cycle 25 (2019\u0026ndash;2024)\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003ctable id=\"Tabb\" border=\"1\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2019\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2020\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2021\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2022\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2023\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2024\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e101\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003e2.4 Geomagnetic storm\u003c/h2\u003e\n \u003cp\u003eA geomagnetic storm occurs when the magnetic field and solar wind of Earth interact more intensely, disrupting the magnetosphere. High-speed solar wind streamers (HSS) and coronal mass ejections (CMEs) are its main energy sources. We used huge, severe, strong, and moderate storms in our investigation, and the information was sourced from the Geomagnetic Equatorial Dst Index Home Page, the website of the World Data Centre (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://wdc.kugi.kyoto-u.ac.jp/\u003c/span\u003e\u003c/span\u003e). The storm events that were observed in 2008\u0026ndash;2013 and 2019\u0026ndash;2024 are listed year-by-year in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. The specifics of the variance in different storm caused by geomagnetic categories are displayed in Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eNumber of geomagnetic storms categorized by intensity\u0026mdash;moderate, strong, severe, and great\u0026mdash;recorded during the periods 2008\u0026ndash;2013 (Solar Cycle 24) and 2019\u0026ndash;2024 (Solar Cycle 25).\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eYear\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eModerate\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eStrong\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSevere\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eGreat\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"6\"\u003e\n \u003cp\u003eSolar Cycle 24 (2008\u0026ndash;2013)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2008\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2009\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2010\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2011\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2012\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2013\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"6\"\u003e\n \u003cp\u003eSolar Cycle 25 (2019\u0026ndash;2024)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2019\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2020\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2021\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2022\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2023\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2024\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNil\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cp\u003eThroughout its approximately 11-year Schwabe cycle, the Sun\u0026rsquo;s activity undergoes remarkable modulation. While the total solar irradiance (TSI) fluctuates modestly\u0026mdash;around \u0026plusmn;\u0026thinsp;0.1% peak-to-peak\u0026mdash;the ultraviolet (UV) and X-ray bands show much larger variations. Specifically, spectral solar irradiance in the UV (e.g., 200\u0026ndash;300 nm) can vary by 50\u0026ndash;100% over a cycle, with Ly-α (121.6 nm) oscillating by tens of percent, and EUV (10\u0026ndash;120 nm) by a factor of ~\u0026thinsp;2\u0026times; (Krivova et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). In contrast, X-ray irradiance\u0026mdash;particularly the soft X-ray (0.1\u0026ndash;0.8 nm) background measured by GOES\u0026mdash;can change by 10\u0026ndash;100 times between solar minimum and maximum (Bruevich and Yakunina \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Rycroft \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Analysis of the 11-year solar activity cycle using long-term sunspot records reveals a strong correlation between solar activity and geomagnetic phenomena, highlighting the critical dependence of geomagnetic research on solar variability (Siingh et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2011\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e displays the monthly variation in sunspot numbers. Specifically, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(a) illustrates the monthly fluctuation during the 2008\u0026ndash;2013 period, representing the first half of Solar Cycle 24. During this time, the sunspot number varied from 0 to 139.1, encompassing both the solar minimum and maximum phases. The minimum phase occurred around 2008\u0026ndash;2009, while the maximum was recorded between 2012 and 2013. Solar Cycle 25, which spans approximately from 2018 to 2024, also includes distinct solar minimum and maximum phases within this timeframe. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(b), the sunspot number during this cycle ranged from 0.2 to 216, with the highest peak observed in this period. The minimum phase of Solar Cycle 25 occurred around 2019\u0026ndash;2021, followed by the maximum phase between 2022 and 2024.\u003c/p\u003e \u003cp\u003eBased on the sunspot number data, it is reasonable to conclude that Solar Cycle 25 has exhibited higher overall solar activity compared to Solar Cycle 24. Bhowmik and Nandy (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) and other dynamo-based models predicted that Cycle 25 would be stronger than Cycle 24, estimating peak sunspot numbers up to ~\u0026thinsp;168\u0026thinsp;\u0026plusmn;\u0026thinsp;16. Similarly, Bisoi et al. (\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), using heliospheric magnetic field data, also forecasted a stronger Cycle 25 compared to Cycle 24. The current results further confirm the findings of these previous works.\u003c/p\u003e \u003cp\u003eThe change in F10.7 cm, a widely used proxy for solar activity, is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Figures\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(a) and 2(b) depict solar radio flux variations during the intervals 2008\u0026ndash;2013 (Solar Cycle 24) and 2019\u0026ndash;2024 (Solar Cycle 25), respectively. In 2008\u0026ndash;2013, F10.7 ranged from 65.7 to 153.5 s.f.u., while in 2019\u0026ndash;2024 it spanned 67 to 245 s.f.u. These findings confirm that Solar Cycle 25 exhibits significantly stronger peak radio flux than Cycle 24. This contrast aligns with prior studies: Tapping (\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) reported an average peak F10.7 of approximately 190\u0026thinsp;\u0026plusmn;\u0026thinsp;35 s.f.u. across cycles since 1950, with the top 15 daily values averaging\u0026thinsp;~\u0026thinsp;350\u0026thinsp;\u0026plusmn;\u0026thinsp;12 s.f.u., and noted that Cycle 24 peaked at ~\u0026thinsp;125\u0026thinsp;\u0026plusmn;\u0026thinsp;20 s.f.u.\u0026mdash;substantially lower than the historical mean (Chin et al. 2011; Pesnel 2020). Conversely, our observed 245 s.f.u. peak during Cycle 25 falls well within the expected range, marking a return toward higher solar activity levels. Moreover, comparative analyses of early-cycle behavior demonstrate that Cycle 24's F10.7 levels (65\u0026ndash;190 s.f.u. during 2008\u0026ndash;2013) were below those of Cycle 23 (65\u0026ndash;283 s.f.u. during 1996\u0026ndash;2001) (Singh and Tonk \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). This further underscores the relative weakness of Cycle 24 compared to its predecessors. In contrast, the elevated and sustained F10.7 values in Cycle 25 signify a clear resurgence in solar activity.\u003c/p\u003e \u003cp\u003eAdditionally, Qian and Mursula (\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) highlighted that while F10.7 remains a useful long-term proxy, recent saturation effects may cause slight overestimation of thermospheric energy input; nonetheless, F10.7 continues to serve as a robust indicator during solar maxima. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e also marks the timing of solar minima and maxima based on the observed F10.7 flux, clearly illustrating that Solar Cycle 25's peak is both higher and broader compared to Cycle 24.\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;1 presents the number of halo CMEs observed annually between 2008\u0026ndash;2013 and 2019\u0026ndash;2024. Figure\u0026nbsp;3 illustrates the variation in the occurrence of halo CMEs (with angular width\u0026thinsp;=\u0026thinsp;360\u0026deg;) during these two time periods. A total of 192 halo CMEs were recorded from 2008 to 2013, whereas 227 were observed between 2019 and 2024. This increase in halo CME events suggests heightened solar activity during the latter period. This trend aligns with broader statistical patterns. Gopalswamy et al. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) found that Cycle 24, despite a\u0026thinsp;~\u0026thinsp;40% decline in sunspot number compared to Cycle 23, exhibited a similar or slightly higher abundance of halo CMEs\u0026mdash;attributed to anomalous CME expansion under weakened heliospheric pressure. Dagnew et al. (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), focusing on Cycles 23 and 24, also reported a 44% higher halo CME rate per sunspot in Cycle 24. These studies suggest that reduced ambient pressure allowed more CMEs to achieve full halo status without necessarily increasing eruption energy or speed. Early evidence from Cycle 25 supports this emerging pattern. Gopalswamy et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) noted that Cycle 25\u0026rsquo;s halo CME occurrence\u0026mdash;normalized by sunspot number\u0026mdash;remains comparable to Cycle 24, both exceeding Cycle 23 levels. They concluded that Cycle 25 mirrors or modestly surpasses Cycle 24 in halo frequency, once again tied to the low solar wind pressure conditions.\u003c/p\u003e \u003cp\u003eTherefore, not only do our observations (192 vs. 227 halo CMEs) reflect elevated solar activity in Cycle 25, but they also corroborate peer-reviewed analyses attributing this increase to both intrinsic cycle strength and ambient heliospheric conditions. The larger halo CME count in 2019\u0026ndash;2024 thus substantiates the conclusion that Solar Cycle 25 represents a renewed phase of enhanced eruptive activity following the subdued Cycle 24.\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents the number of geomagnetic storms categorized by intensity\u0026mdash;moderate, strong, severe, and great\u0026mdash;recorded annually between 2008\u0026ndash;2013 (Solar Cycle 24) and 2019\u0026ndash;2024 (Solar Cycle 25). During 2008\u0026ndash;2013, a total of 92 moderate storms and 12 strong storms were observed, with no severe or great storms reported. In contrast, from 2019 to 2024, geomagnetic activity intensified: 145 moderate storms, 29 strong storms, and 5 severe storms were recorded. Notably, no geomagnetic storms occurred in 2019, which corresponds with the solar minimum at the start of Cycle 25.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e illustrates the distribution of geomagnetic storm categories across the two periods. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a), there was a significant increase in powerful geomagnetic storms (strong and severe) during 2019\u0026ndash;2024, compared to Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b), which depicts the relatively quiet period of 2008\u0026ndash;2013. The presence of five severe storms in Solar Cycle 25, and none in Cycle 24, further reinforces the observed difference in solar and geomagnetic activity levels between the two cycles. This increase in geomagnetic storm activity correlates with the higher frequency of halo CMEs during 2019\u0026ndash;2024. Previous studies have established a strong connection between halo CMEs and intense geomagnetic storms (Gopalswamy et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), as halo CMEs\u0026mdash;especially Earth-directed ones\u0026mdash;are often responsible for severe space weather events. Therefore, the lower number of halo CMEs recorded between 2008\u0026ndash;2013 likely contributed to the reduced geomagnetic activity in that period.\u003c/p\u003e \u003cp\u003eTaken together with the data presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, these findings support the conclusion that Solar Cycle 24 exhibited significantly lower solar and geomagnetic activity compared to Solar Cycle 25. This difference is consistent with recent studies suggesting that the ambient heliospheric conditions and CME characteristics in Cycle 25 are more conducive to triggering geoeffective events (Kilpua et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Gopalswamy et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e"},{"header":"4. Summary and Conclusions","content":"\u003cp\u003eThis study presents a comprehensive comparative analysis of five key solar and geomagnetic parameters: sunspot number, F10.7 cm radio flux index, halo coronal mass ejections (CMEs), and geomagnetic storm frequency and intensity during the early and peak phases of Solar Cycles 24 and 25. While prior studies have explored these variables as case study for individual parameters for individual cycles, a direct comparison between Cycles 24 and 25 has remained relatively unexplored. This work addresses that gap by evaluating the first six years of Solar Cycle 24 (2008\u0026ndash;2013) alongside the corresponding period of Solar Cycle 25 (2019\u0026ndash;2024).\u003c/p\u003e \u003cp\u003eThe key findings of this comparative analysis are summarized as follows:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eMonthly sunspot numbers ranged from 0.2 to 216 during Solar Cycle 25 and from 0 to 139.1 during Solar Cycle 24. The greater maximum and broader distribution in Cycle 25 suggest enhanced solar magnetic activity relative to Cycle 24.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eBoth solar cycles began with anomalously quiet conditions, as evidenced by the near absence of sunspots during 2008\u0026ndash;2009 and 2019\u0026ndash;2020. Such deep and prolonged minima have not been observed in nearly a century, emphasizing the unusual onset of both cycles.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eThe solar radio flux F10.7 cm index ranged from 65.7 to 153.5 s.f.u. in Cycle 24, compared to 67 to 245 s.f.u. in Cycle 25. This substantial increase in peak values during Cycle 25 indicates stronger emissions from active solar regions, consistent with heightened solar EUV and X-ray output.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eA total of 192 halo CMEs was reported between 2008 and 2013, while 227 events occurred from 2019 to 2024. The increase in Earth-directed CME events further supports the conclusion of greater eruptive activity during Cycle 25.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eFrom 2019 to 2024, 179 geomagnetic storms were observed, including 145 moderate, 29 strong, and 5 severe events. This contrasts with 104 storms in Cycle 24 (92 moderate, 12 strong), confirming enhanced geomagnetic disturbances during Cycle 25, likely driven by more frequent and energetic CMEs.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eOverall, these results demonstrate that Solar Cycle 25 has so far exhibited stronger and more sustained solar and geomagnetic activity than Solar Cycle 24. This has significant implications for space weather forecasting and the understanding of long-term solar variability. Future work should focus on extending this comparison through the declining phase of Cycle 25 and examining associated impacts on the near-Earth space environment.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAK analyzed various data and wrote the initial draft. DB helped analyze F10.7 flux data. The AKM conceptualized the idea, supervised the analysis, and modified the draft. UP helped write, review, and edit the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements:\u003c/h2\u003e \u003cp\u003eAKM thanks to Anusandhan National Research Foundation (ANRF), New Delhi, India for the CORE research grant (CRG/2021/001322) which supported this work\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets generated and analyzed during the current study are available from the corresponding websites: https://www.sidc.be/SILSO/datafiles; https://spaceweather.gc.ca/forecast-prevision/solar-solaire/solarflux/sx-5-en.php; https://cdaw.gsfc.nasa.gov/CME_list/halo/halo.html; https://wdc.kugi.kyoto-u.ac.jp/\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAgee, E. M., Cornett, E., \u0026amp; Gleason, K. (2010). 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Another Mini Solar Maximum in the Offing: A Prediction for the Amplitude of Solar Cycle 25. \u003cem\u003eJournal of Geophysical Research: Space Physics\u003c/em\u003e, 125(7).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Solar Cycle, F10.7 cm radio flux, Sunspot Number, Coronal Mass Ejection (CME), Geomagnetic Storm, Solar indices","lastPublishedDoi":"10.21203/rs.3.rs-6996698/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6996698/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study presents a comparative analysis of solar activity during the first six years of Solar Cycles 24 (2008–2013) and 25 (2019–2024). The analysis focuses on key solar and geophysical parameters, including sunspot numbers, halo coronal mass ejections (CMEs), solar radio flux at 10.7 cm (F10.7), and geomagnetic storms, to assess differences in solar behavior between the two cycles. Sunspot numbers varied between 0 and 139.1 in Solar Cycle 24, whereas they ranged from 0.2 to 216 during the corresponding period of Solar Cycle 25. Similarly, the F10.7 cm radio flux fluctuated between 65.7 and 153.5 s.f.u. during 2008–2013, and between 67.05 and 245.6 s.f.u. from 2019 to 2024, reflecting an overall increase in solar output. The study also includes an analysis of halo CMEs, with 192 events observed during Solar Cycle 24 and 227 during Solar Cycle 25, both characterized by an angular width of 360°. Geomagnetic activity was assessed using 104 events from Cycle 24 and 179 from Cycle 25, with Disturbance Storm Time (Dst) index values ranging from –50 to –350 nT. The results indicate a significant increase in solar activity during the early phase of Solar Cycle 25 compared to Solar Cycle 24. This suggests a more intense and dynamic space weather environment in the current solar cycle, which may have important implications for space weather forecasting and satellite operations.\u003c/p\u003e","manuscriptTitle":"Comparative Assessment of Solar and Geophysical Parameters During the Initial Six Years of Solar Cycles 24 and 25","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-02 11:56:39","doi":"10.21203/rs.3.rs-6996698/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2c719044-c1cf-4941-919d-e5617d9410ce","owner":[],"postedDate":"July 2nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-02T13:08:55+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-02 11:56:39","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6996698","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6996698","identity":"rs-6996698","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}