The solar activity by wavelet-based multifractal analysis

Analysis of the monthly mean interannual variations of the total ozone (Total Ozone Mapping Spectrometer (TOMS, TOMS‐Meteor 3)), surface air temperature (National Centres for Environmental Prediction and Atmospheric Research (NCEP/NCAR) reanalysis) and their relations is conducted by means of the singular value decomposition (SVD) for each month December–March 1979–1994. It is shown that the total ozone increase (decrease) occurs almost over those geographical regions where cooling (warming) is observed both on the interannual and longer time‐scales Strong non‐local correlations were indicated between the total ozone changes over England in January and surface temperature variations in western Siberia, southern European Russia and the Azores in February. Similar relations occur for the total ozone (February) and surface temperature (March) changes. These results can be used for the empirical extended‐range forecasts of the anomalously cold winters in Europe and Russia using the total ozone data. Possible mechanisms for this non‐local linkage and its relation to the Arctic Oscillation are discussed.

This study systematically investigates the complicated link between solar activity indicators, specifically sunspot numbers (SSN) and solar radio flux (F10.7), and the occurrence of geomagnetic storms during Solar Cycles 24 and 25. The primary objective is to quantify the influence of these solar parameters on Earth's magnetospheric disturbances. The methodology involved a detailed analysis of 231 peak Disturbance Storm Time (Dst) events (P), 214 initial phase (P-I) geomagnetic storm events, and 201 recovery phase(P-R) geomagnetic storm events, all identified by a Dst threshold of ≤ -50 nT, covering the period from January 2008 to June 2024. Statistical analysis, primarily through the calculation of Pearson correlation coefficients, revealed robust positive correlations. Peak Dst events exhibited correlation coefficients of 0.67 with sunspot numbers and 0.72 with solar radio flux. Similarly, geomagnetic storm events during the initial phase showed strong positive correlations with sunspot numbers (r = 0.69) and solar radio flux (r = 0.73). A comparable positive correlation was also observed during the recovery phase, with coefficients of 0.69 for sunspots and 0.73 for solar radio flux. A particularly striking finding was the exceptionally high correlation of 0.98 between the yearly average sunspot number and yearly average solar radio flux, underscoring the profound interconnectedness of these two solar parameters. These findings highlight the significant predictive potential of sunspot numbers and solar radio flux in forecasting geomagnetic storm activity. The consistent strength of these correlations across different storm phases suggests that solar activity levels exert a sustained influence throughout the entire evolution of a geomagnetic disturbance, not merely its onset. Furthermore, the comparative analysis of Solar Cycle 24, which was historically weak, and the rapidly rising Solar Cycle 25 offers important clues about the evolving character of solar magnetic variability and its implications for space weather dynamics. The observed resurgence of activity in Cycle 25 implies a heightened likelihood of geo-effective space weather events compared to the preceding cycle.

The main aim of the present study is to investigate further the association between total ozone (TOZ) and the 11 year solar cycle (SC) during the period 1979–2010, by employing satellite observations of TOZ made by Nimbus‐7, Meteor‐3, Earth Probe Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) instrumentation. A statistically significant correlation between the annual mean TOZ over both hemispheres and sunspot number (SN) is found. On the contrary, focusing on the January and February mean monthly TOZ fluctuations from the equator to the high latitudes of the Northern Hemisphere, no association between TOZ and SN is derived. This is attributed to the existence of the quasi‐biennial‐oscillation (QBO) and the El Niño‐Southern oscillation (ENSO) in the TOZ time series. The latter oscillation is herewith expressed by the recently introduced Ozone ENSO Index (OEI). However, when considering the TOZ zonal means centred at 17.5 and 27.5°N during the east phase years of the QBO in the equatorial zonal wind at 50 hPa, a statistically significant correlation between TOZ and SN is revealed. It is an indication that the quasi‐periodic fluctuations (i.e. QBO, ENSO) strongly contaminate the relationship between TOZ and solar activity. Plausible mechanisms are discussed, exploring the momentum flux (MF) measurements between 45 and 75°N, in the periods of increased dynamical variability. The findings obtained point to the conclusion that the 11 year solar cycle response in TOZ is caused by dynamical changes which are caused by solar activity. These are of crucial importance because solar radiation is a major driving force of the climate system. Copyright © 2012 Royal Meteorological Society

\n Aims. The study aims to find a relationship between the rotation of the small bright coronal structures (SBCS) described by the solar rotation parameters and indices of solar activity on monthly and yearly temporal scales.\n Methods. We analyse precise measurements of the solar differential rotation determined by tracing SBCS in SOHO-EIT images and compare the derived solar rotation parameters with the status of solar activity in the period 1998 − 2006. Full-disc solar images obtained with the Extreme ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO) were used to analyse solar differential rotation determined by tracing SBCS. An automatic method to identify and track the SBCS in EIT full-disc images with a six hour cadence is applied. We performed a statistical analysis of the monthly and yearly values of solar sidereal rotation velocity parameters A and B (corresponding to the equatorial rotation velocity and the gradient of the solar differential rotation, respectively) as a function of various solar activity indices.\n Results. The dependence of the solar rotation on the phase of the solar cycle was found. It is clearly visible for the solar rotation parameter A, whilst the results are not conclusive for parameter B. The relationship between the solar rotation and activity, expressed by the monthly relative sunspot number, the smoothed monthly relative sunspot number, the yearly relative sunspot number, and the interdiurnal variability (IDV) index was investigated. The statistically significant correlation was found for the solar rotation parameter A, whilst a very low and insignificant correlation was obtained for the rotation parameter B. \n Conclusions. During the maximum of the solar cycle 23 and just after it, the equatorial solar rotation velocity was lower than in other phases of the cycle, when there was less activity. This is consistent with other observational findings, obtained by different tracers and methods.\n

Abstract. The short- and long-term variability of the surface spectral solar ultraviolet (UV) irradiance is investigated across Italy using high-quality ground-based measurements from three locations: Aosta (45.7∘ N, 7.4∘ E, 570 m a.s.l.), Rome (41.9∘ N, 12.5∘ E, 15 75 m a.s.l.), and Lampedusa (35.5∘ N, 12.6∘ E, 50 m a.s.l.). The three sites are characterized by different environmental conditions and represent almost the full latitudinal extent of the Italian territory. Data of two periods were analysed: 2006–2020 (all sites) and 1996–2020 (Rome only). The main objective of this study is to quantify the effect of the geopotential height (GPH) at 250 hPa on total ozone, and spectral irradiance at 307.5 and 324 nm. We first show that monthly anomalies in GPH, total ozone, and spectral irradiances are correlated amongst the three sites, suggesting that Italy is often affected by the same synoptical weather systems. We further find statistically significant anticorrelations between GPH and monthly anomalies in total ozone for all stations and months. Conversely, we identify positive correlations between GPH and monthly anomalies in spectral irradiance at 307.5 nm for most months. The influence of GPH on short-term variability also hold for long-term trends. For example, long-term changes in total ozone over the period 2006–2020 were associated with changes in GPH for all stations. This suggests that observed negative trends in total ozone were mainly driven by changes in lower-stratospheric ozone as upper-stratospheric ozone was increasing over this period. For several months of the year, positive trends in UV irradiance were observed, and we found that these trends were predominantly caused by changes in clouds and/or aerosols instead of total ozone. For the longer period of 1996–2020, a statistically significant annualized decrease in total ozone of ∼ 0.1 % per year was identified for Rome and could subsequently be attributed to decreasing lower-stratospheric ozone. While positive trends in spectral irradiance at 307.5 nm were observed for several months of this extended period, the negative trend in total ozone did not lead to a positive trend in the spectral irradiance at 307.5 nm in the deseasonalized data. Our study provides evidence that dynamical processes taking place in the troposphere lead to significant variability in total ozone and surface solar UV irradiance.

Impact of solar and geomagnetic activities on total column ozone in China

In this study the short- and long-term variability of the surface spectral solar ultraviolet (UV) irradiance are investigated over Italy using high quality ground based measurements from three sites located at quite different environmental conditions, and covering the full latitudinal extent of the Italian territory: Aosta (45.7° N, 7.4° E, 570 m a.s.l.), Rome (41.9° N, 12.5° E, 75 m a.s.l.), and Lampedusa (35.5° N, 12.6° E, 50 m a.s.l.). The variability of the irradiances at 307.5 nm, 324 nm, and of the ratio between the 307.5 nm and the 324 nm irradiances were investigated with respect to the corresponding variability in total ozone and the geopotential height at 250 hPa (GPH). The study was performed for two periods: 2006–2020 for all stations, and 1996–2020 only for Rome. A statistically significant correlation between the GPH and total ozone monthly anomalies was found for all stations and all seasons of the year. A corresponding statistically significant correlation was also found in most cases between the GPH and the 307.5 nm irradiance monthly anomalies. The correlation between GPH anomalies at different sites was statistically significant, possibly explaining the strong and significant correlation between the total ozone monthly anomalies at the three sites. A statistically significant decrease of total ozone, of ~0.1 %/year was found for Rome for the period 1996–2020, which however did not induce increasing trends in irradiance at 307.5 nm (neither increasing trends in the ratio between the 307.5 nm and the 324 nm irradiances) at SZA = 67°. Further analyses revealed positive trends in the ratio and the 307.5 nm irradiance at smaller solar zenith angles (SZA), which can be attributed to the fact that total ozone decrease is driven by a decrease in the lower stratosphere while upper stratospheric ozone increases, and the effect of changes of upper stratospheric ozone becoming disproportionately larger for increasing SZA. It was also showed that long-term changes in total ozone follow changes in GPH, which is an additional indication that negative trends in total ozone are mainly driven by changes in lower stratospheric ozone. An anti-correlation between the GPH long-term changes and total ozone was also evident for all stations in 2006–2020. Positive trends in UV irradiance for this latter period which were possibly driven by changes in clouds and/or aerosols were found for Rome and Aosta. This study clearly points out the significance of dynamical processes which take place in the troposphere for the variability of total ozone and surface solar UV irradiance.

Abstract. We present the first spatial analysis of "fingerprints" of the El Niño/Southern Oscillation (ENSO) and atmospheric aerosol load after major volcanic eruptions (El Chichón and Mt. Pinatubo) in extreme low and high (termed ELOs and EHOs, respectively) and mean values of total ozone for the northern and southern mid-latitudes (defined as the region between 30° and 60° north and south, respectively). Significant influence on ozone extremes was found for the warm ENSO phase in both hemispheres during spring, especially towards low latitudes, indicating the enhanced ozone transport from the tropics to the extra-tropics. Further, the results confirm findings of recent work on the connection between the ENSO phase and the strength and extent of the southern ozone "collar". For the volcanic eruptions the analysis confirms findings of earlier studies for the northern mid-latitudes and gives new insights for the Southern Hemisphere. The results provide evidence that the negative effect of the eruption of El Chichón might be partly compensated by a strong warm ENSO phase in 1982–1983 at southern mid-latitudes. The strong west-east gradient in the coefficient estimates for the Mt. Pinatubo eruption and the analysis of the relationship between the AAO and ENSO phase, the extent and the position of the southern ozone "collar" and the polar vortex structure provide clear evidence for a dynamical "masking" of the volcanic signal at southern mid-latitudes. The paper also analyses the contribution of atmospheric dynamics and chemistry to long-term total ozone changes. Here, quite heterogeneous results have been found on spatial scales. In general the results show that EESC and the 11-yr solar cycle can be identified as major contributors to long-term ozone changes. However, a strong contribution of dynamical features (El Niño/Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Antarctic Oscillation (AAO), Quasi-Biennial Oscillation (QBO)) to ozone variability and trends is found at a regional level. For the QBO (at 30 and 50 hPa), strong influence on total ozone variability and trends is found over large parts of the northern and southern mid-latitudes, especially towards equatorial latitudes. Strong influence of ENSO is found over the Northern and Southern Pacific, Central Europe and central southern mid-latitudes. For the NAO, strong influence on column ozone is found over Labrador/Greenland, the Eastern United States, the Euro-Atlantic Sector, and Central Europe. For the NAO's southern counterpart, the AAO, strong influence on ozone variability and long-term changes is found at lower southern mid-latitudes, including the southern parts of South America and the Antarctic Peninsula, and central southern mid-latitudes.

Solar activities have obvious effects on earth＇s climate. Many scientists have studied the relationship between solar activities and climate change, and a lot of papers have been published in this field. The relative sunspot numbers is an important factor in the research of solar activities. Wavelet transform is a fine method to analyze time serials periods. By using different data, the periods are different. In the past time, many scholars had analyzed solar activities by others statistical methods, found that changes of solar activity have periods of 5-6 years, 11 years, 22 years, 80-100 years, and so on. The periods are so disunity that they can＇t be better used to forecast change trend of solar activities. In this paper, being applied to analysis of solar activities, the wavelet transform method was introduced to analyze periods change, and found some meaningful results. The relative sunspot numbers change with periods of 10.7 year and 101 year. The 10.7 year period is remarkable, and it＇s amplitude varies with time. In 1935 to 2000, the amplitude of 10.7 year period are especially distinct. The solar activities exist strong or weak phases. Abrupt change occurred in 1950 year, and solar activities became stronger since 1950. It is predicled that the solar activity will be weaker in the near future.

This article is an update of a study (Tapping and Valdes in Solar Phys. 272, 337, 2011) made in the early part of Cycle 24 using an intercomparison of various solar activity indices (including sunspot number and the 10.7 cm solar radio flux), in which it was concluded that a change in the relationship between photospheric and chromospheric/coronal activity took place just after the maximum of Cycle 23 and continued into Cycle 24. Precursors (short-term variations) were detected in Cycles 21 and 22. Since then the sunspot number index data have been substantially revised. This study is intended to be an update of the earlier study and to assess the impact of the revision of the sunspot number data upon those conclusions. This study compares original and revised sunspot number, total sunspot area, and 10.7 cm solar radio flux. The conclusion is that the transient changes in Cycles 21 and 22, and the more substantial change in Cycle 23, remain evident. Cycle 24 shows indications that the deviation was probably another short-term one.

The starting times of mass spontaneous social movements have been compared with temporal changes in solar activity (Wolf numbers) and in the Aa index of geomagnetic activity. It is shown that relatively high values of solar and, hence, geomagnetic activity are typical (on average) of a set of years when social cataclysms began. In addition, the relationship between social activity and geomagnetic activity is expressed somewhat more strongly than with solar activity. Heliogeomagnetic activity itself is not, however, the cause of social conflicts, as is evidenced by the weakness of the statistical relationship and the fact that the time intervals of an extremely large number of social conflicts (the decades of the 1800s, 1910s, and 1990s) occur during periods of a reduced mean level of solar and geomagnetic activity. From an averaged statistical model of the solar-geomagnetic influence on social activity and the current status and forecast of the 24th solar cycle, we can assume that heliogeomagnetic factors will contribute to an increased level of sociopolitical activity at least until the end of 2014 and, possibly, a little longer.

Hysteresis, time lag, and relation between solar activity and cosmic rays during solar cycle 24

Variability of sunspot cycle QBO and total ozone over high altitude western Himalayan regions

A global three-dimensional chemical transport model is being developed for forecasting total ozone. The model includes detailed stratospheric chemistry and transport and couples with a dynamical module of the Meteorological Research Institute/Japan Meteorological Agency 1998 (MRI/JMA98) general circulation model, which can yield realistic atmospheric fields through a meteorological assimilation system. Its predictability on total ozone is investigated for up to 4 weeks from 1997 to 2000. Global root-mean-square errors (rmses) of a control run are approximately 10 DU (3% of total ozone) throughout a year; the control run results are used as initial values for hindcast experiments. Rmses of the hindcast experiments globally range from 10 to 30 DU. The anomaly correlation between the 5-day forecasts and satellite measurements is approximately 0.6 throughout a year in the mid- and high latitudes of both the Northern and Southern Hemispheres. Thus, the model has potential for utilization on total ozone forecasts up to 5 days. In the northern mid- and high latitudes, the model produces better total ozone forecasts than the persistence up to 2 weeks, indicating that the deterministic limit of the total ozone forecasts is durationally comparable to that of weather forecasts. Good correlations between changes in total ozone and 100-hPa geopotential height reveal that the predictability of the dynamical field in the lower stratosphere critically affects the predictability of total ozone.

Relationship between sunspot number and seasonal rainfall over Kerala using wavelet analysis