Solar activity affects space weather and many space-borne and ground-based high-technological systems. Knowing the solar activity level in advance is important for modern humans’ lives. Among the many methods proposed to date for the prediction of the strength of the next solar cycle, the most in demand are the numerous precursor methods focused on a single chosen parameter at a given time as the dominant indicator of future solar activity. Here, we used the amplitude of the previous cycle as a precursor. A significant positive correlation was found between the amplitudes of the odd-numbered and the next even-numbered cycles. The correlation coefficient was equal to 0.57 when the pair of cycles 7-8 was not taken into account. Using the obtained regression equation for maxima of odd- even cycles and the amplitude of the current Solar Cycle 25 (160.8 in October 2024), we estimated the strength of the next Solar Cycle 26. Solar Cycle 26 is predicted to have an amplitude of 142.2 ± 52.7. This means that it will be higher than Solar Cycle 24 and lower than Solar Cycle 25. Using this predicted amplitude of Solar Cycle 26 and regression equation for maxima of even-odd cycles we can also estimate the amplitude of Solar Cycle 27 to be equal to 188.4±67.4. Solar activity will grow in the next decades and no grand solar minimum like Dalton or Maunder minimum is expected.

The objective of this paper is to reproduce and predict the series of solar cycle amplitudes using a simple time-series model that takes into account the variable time scale of the Gleissberg oscillation and the absence of clear evidence for odd–even alternation prior to Solar Cycle 9 (SC9). It is demonstrated that the Gleissberg oscillation can be quite satisfactorily modelled as a sinusoidal variation of constant amplitude with a period increasing linearly with time. Subtracting this model from the actual cycle amplitudes, a clear even–odd alternating pattern is discerned in the time series of the residuals since SC9. For this period of time, the mean value of the residuals for odd-numbered cycles is shown to exceed the value for even-numbered cycles by more than 4σ, providing the clearest evidence yet for a persistent odd–even–odd alternation in cycle amplitudes. Random deviations from these means are less than half the standard deviation of the raw cycle amplitude time series for the same period, which allows the use of these regularities for solar cycle prediction with substantially better confidence than the simple climatological average. Predicted cycle amplitudes are found to be robust against the addition or omission of some data points from the input set, and the method correctly hindcasts SC23 and SC24. The potential physical background of the regularities is also discussed. Our predictions for the amplitudes of SC25, SC26, and SC27 are 155.8±20.7, 96.9±25.1 and 140.8±20.7, respectively. This suggests that the amplitude of SC26 will be even lower than that of SC24, making it the weakest cycle since the Dalton Minimum.

ABSTRACTThe results of radiocarbon variation studies observed in annual tree rings from the NW Pacific (USA Northwest) (Stuiver and Braziunas 1993) and Europe (England, Brehm et al. 2021; Slovakia, Povinec 1977, 1987) are reviewed with the aim of better understanding the 11-year radiocarbon cycle and possible impacts of solar proton events on 14C levels in the atmosphere and biosphere. The average Δ14C amplitude in tree rings for the period of 1798–1944 was 1.3 ± 0.3‰, the average periodicity was 11 ± 1 years, and the average time shift between the sunspot numbers and Δ14C records was 3 ± 1 years. A new solar activity minimum (Gleissberg minimum, 1878–1933) has been identified in the Δ14C data sets from the NW Pacific and England, showing Δ14C excess of 7‰, comparable to the Dalton minimum (1797–1823). No significant changes in Δ14C levels were identified that could be associated with solar proton events during 1800–1950.

To reconstruct naturally and anthropogenically induced environmental change in SE Europe since the Little Ice Age, we have examined five partially varved sediment cores from coastal Lake Vouliagmeni, Greece. Our reconstructions are based on a multi-proxy approach including microfacies analysis, X-ray fluorescence core scanning, radionuclide dating (210Pb, 137Cs, and 241Am), and palynological analysis (pollen, spores, and dinoflagellate cysts). A 131 -cm-long composite record that encompasses the past c. 300 years reveals 181 varves of endogenic and mixed clastic-biogenic types. The formation of these varves was controlled by seasonal variability in clastic input and primary productivity. The non-varved intervals consist of homogenous lake sediments and turbidite deposits. Based on a chronology developed through radionuclide dating, varve counting and exclusion of turbidites from the sequence, we have compared our proxy data with meteorological data and historical records of earthquakes and human activities. Our results suggest that the surroundings of Lake Vouliagmeni experienced relatively wet conditions during the late solar Maunder Minimum (1645–1715 AD) and relatively dry conditions during the Dalton Minimum (1790–1830 AD), which highlights the hydroclimatic heterogeneity in SE Europe during the Little Ice Age. The evaluation of historical documentation suggests that the majority of the turbidites is related to lake-slope instabilities following earthquake shocks. Human impact on Lake Vouliagmeni includes (i) a change in aquatic biota following the artificial connection of the lake to the sea at c. 1880 AD, and (ii) expansion of agricultural areas and reduction of natural forests around the lake due to population growth over the past 300 years.

Estimation of the Average Values of the Wolf Numbers of Cycles of the Dalton Minimum Based on the Characteristics of Reliable Cycles of a Series

ABSTRACT French astronomer Honoré Flaugergues compiled astronomical observations in a series of handwritten notebooks for 1782–1830, which are preserved at Paris Observatory. We reviewed these manuscripts and encoded the records that contain sunspot measurements into a numerical table for further analysis. All measurements are timings, and we found three types of measurements, allowing the reconstruction of heliographic coordinates. In the first case, the Sun and sunspots cross vertical and horizontal wires; in the second case, one vertical and two mirror-symmetric oblique wires; and in the third case, a rhombus-shaped set of wires. Additionally, timings of two solar eclipses also provided a few sunspot coordinates. As a result, we present the time–latitude (butterfly) diagram of the reconstructed sunspot coordinates, which covers the period of the Dalton Minimum and confirms consistency with those of Derfflinger and Prantner. We identify four solar cycles in this diagram and discuss the observed peculiarities as well as the data reliability.

The wavelet analysis was used to study the spectral composition of the sunspot numbers SN during1700–2021. In addition to the dominant 11-year component, two powerful components of the Gleissbergcycle can be traced in the spectrum: before 1880, a branch with a period of ~60 years; from 1850 a branch of~115 years is found. It is found that the series of lengths and amplitudes of the solar cycle as a whole areinversely related (correlation coefficient k = –0.5–0.63). The interval between the series at which the maximumanticorrelation is reached depends on time. In the 18th and early 19th centuries, the lag was equal toone cycle, in the 19th century it was two cycles, and from 1950 to our time the lag decreased to 2 years. Quasiperiodicstructures, which are typical for long periods of low solar activity, have been identified. Such a spectralfeature in ~1800 (Dalton minimum) was caused by the influence of the 60-year branch, while the onethat has been forming since the beginning of the 21st century is due to the weaker influence of the circa-centenarybranch. Therefore, it should be expected that the next solar cycles will be higher and shorter thanduring the period of the Dalton minimum. It has been shown that solar cycle length variations for the last321 years can be described within the framework of the model, which is an 11-year oscillation that is subjectto frequency modulation by the branches of the Gleisberg cycle (60 and 115 years) with time-varying influencesof the modulator

The source material for the number of Wolf numbers is both archival records of disparate observationsand regular observatory observations. Many researchers rely on a series of Wolf numbers, includingrestored data of archival records, although the properties and characteristics of the restored and reliable partsof the series differ significantly. The parameters of the restored part itself are also contradictory. Naturally,matching the properties of the reconstructed and reliable series will smooth the contradictions and expandthe array of more reliable data. Taking the relationship between the characteristics of significant cycles intoaccount, options for group correction of the average values of cycles I–IX are presented. Since local dataresiduals play a lesser role when comparing extended fragments, by relying on the integral estimates of thesefragments (without detailing the conditions for their formation) we obtained more weighted interval estimates.The parameters of intervals (groups of cycles) of a reliable series serve as the basis for correction.

Variability of solar periodicities in southern African baobab δ 13 C data during the Wolf, Spörer, Maunder and Dalton minima

Solar cycle 25 amplitude prediction based on sunspot number increase rate

On a centennial timescale, solar activity oscillates quasi-periodically and also tends to occasionally get into a low-activity period. The Dalton Minimum (circa 1790s–1820s) was one of such low-activity periods that had been captured in telescopic sunspot observations. However, it has been challenging to analyse the Dalton Minimum, as contemporary source records remained mostly unpublished and almost inaccessible to the scientific community. Recent studies have established reliable datasets for sunspot group number, sunspot number, and sunspot positions. This study further analyzes independent Silesian sunspot observations from 1800 to 1827 in a manuscript from the Library of Wrocław University (Ms AKC.1985/15) and complements it with the metadata for the observer: Karl Christian Reinhold von Lindener. We identified 547 days of sunspot observations in these records and derived the sunspot group number, individual sunspot number, and sunspot positions between 1800 and 1827. The results of this study have significantly revised von Lindener’s sunspot group number, which was previously known for only 517 days in scientific databases, and removed contamination from general descriptions. Using our results, we extended investigations into individual sunspot counts and derived their positions. In our analysis, we locate von Lindener’s sunspot positions in both solar hemispheres and contrast the Dalton Minimum with the Maunder Minimum, adding further independent credits to the previous results for Derfflinger’s and Prantner’s datasets. Sunspot positions are also slightly biased towards the northern solar hemisphere in early Solar Cycle 6 (1812–1813). The high-latitude sunspot positions indicate the onset of Solar Cycle 7 as early as June 1822.

A prediction of the amplitude of the 25th cycle of solar activity is proposed based on the analysis of data on 24 previous solar cycles, which relate to the statistical relationship between the rate of increase in the number of sunspots in the phase of the growth curve and the amplitude of the cycle. It turned out that the forecasting result depends on which section of the growth curve is taken as the basis for forecasting, as well as whether all 24 cycles are taken into account, or only the odd ones. The prediction result is also affected by the initial assumption about monotonicity or non-monotonicity of the growth phase. A comparison of the rates of sunspot growth in different parts of the growth phase of different cycles shows that the current cycle #25 does not show early signs of non monotonic growth similar to those observed in the 24th cycle. It was concluded that, most likely, the maximum smoothed number of sunspots in the 25th cycle W max (25) should be equal to 185 ± 18 units in the new system, which corresponds to the average power of the solar cycle, with the implementation of the Hnievyshev-Ohl rule. However, if cycle #25 will still have a non-monotonic curve of the growth phase, similar to such a curve in the previous cycle #24, then W max (25) » 130. With such parameters of this cycle, there are no signs of approaching the deep minimum of the age cycle in the middle 21st century. This does not exclude the fact that this deep age minimum can occur suddenly and sharply immediately after the 25th cycle, as was the case, for example, in the Dalton minimum.

Abstract. The early 19th century was the coldest period over the past 500 years, when strong tropical volcanic events and a solar minimum coincided. The 1809 unidentified eruption and the 1815 Tambora eruption happened consecutively during the Dalton minimum of solar irradiance; however, the relative role of the two forcing (volcano and solar) agents is still unclear. In this study, we examine the responses from a set of early 19th century simulations with combined and separated volcanic and solar forcing agents, as suggested in the protocol for the past1000 experiment of the Paleoclimate Modelling Intercomparison Project – Phase 4 (PMIP4). From 20-member ensemble simulations with the Max Planck Institute Earth system model (MPI-ESM1.2-LR), we find that the volcano- and solar-induced surface cooling is additive in the global mean/large scale, regardless of combining or separating the forcing agents. The two solar reconstructions (SATIRE (Spectral and Total Irradiance REconstruction-Millennia model) and PMOD (Physikalisch-Meteorologisches Observatorium Davos)) contribute to a cooling before and after 1815 of ∼0.05 and ∼0.15 K monthly average near-surface air cooling, respectively, indicating a limited solar contribution to the early 19th century cold period. The volcanic events provide the main cooling contributions, inducing a surface cooling that peaks at ∼0.82 K for the 1809 event and ∼1.35 K for Tambora. After the Tambora eruption, the temperature in most regions increases toward climatology largely within 5 years, along with the reduction of volcanic forcing. In the northern extratropical oceans, the temperature increases slowly at a constant rate until 1830, which is related to the reduction of seasonality and the concurrent changes in Arctic sea-ice extent. The albedo feedback of Arctic sea ice is found to be the main contributor to the Arctic amplification of the cooling signal. Several non-additive responses to solar and volcanic forcing happen on regional scales. In the atmosphere, the stratospheric polar vortex tends to strengthen when combining both volcano and solar forcing, even though the two forcing agents separately induce opposite-sign changes in stratospheric temperatures and zonal winds. In the ocean, when combining the two forcings, additional surface cold water propagates to the northern extratropics from the additional solar cooling in the tropics, which results in regional cooling along the propagation. Overall, this study not only quantifies the surface responses from combinations of the volcano and solar forcing, but also highlights the components that cannot be simply added from the responses of the individual forcing agents, indicating that a relatively small forcing agent (such as solar in early 19th century) can impact the response from the large forcing (such as the 1815 Tambora eruption) when considering regional climates.

Abstract Solar eclipses have been recorded throughout history and across various ethnic groups. Their records have benefitted scientific discussions on multiple topics. These astronomical spectacles have also been recorded in the Japanese archipelago, but little has been known of the historical observations in the northern end: Hokkaido Island (known as Ezo Island until 1869). Here, we analysed three such early eclipse accounts from Hokkaido Island, both philologically and astronomically. We first analysed Tokunai Mogami's eclipse account written in 1786 January, which has been associated with the earliest eclipse record in Hokkaido Island. Our analysis showed that this eclipse was a deep partial solar eclipse outside the annular totality path of a hybrid eclipse, whereas it had previously been associated with an annular solar eclipse. This eclipse was also witnessed in the Ryukyu Kingdom, probably as a deep partial eclipse. We also located eclipse sketches in Kan’ichiro Mozume's diary and confirmed the local visibility of the annular eclipse in Otaru in 1872 June. We further analysed John Batchelor's eclipse folklore and identified the reported eclipse with a total solar eclipse in 1824 June. This folklore reported “tongues of fire and lightning” from the side of the “black dead sun.” This description is morphologically consistent with that of solar coronal streamers around the solar minima. This eclipse is chronologically located around the minimum of Solar Cycles 6/7 and contrasts the Dalton Minimum with the Maunder Minimum, for which coronal streamers were reportedly missing, according to visual observations.

Fire history and its forcing in Northeastern Asia boreal forests

Abstract The Dalton minimum is considered to be one of the unique solar activity periods that have been captured in direct sunspot observations since 1610. Specifically, the solar magnetic field in this period is of great interest. Derfflinger and Prantner’s sunspot observations of 1802–1824 and 1800–1844 are the most important references for this period. To understand the solar magnetic activity in the Dalton minimum, it is important to estimate the latitude/longitude distribution of the sunspots and the sunspot areas for that duration. In this study, we analyze Derfflinger and Prantner’s sunspot drawings to determine the sunspot parameters, particularly the sunspot area. We find that the sunspot areas obtained from Derfflinger’s drawings are overemphasized by a factor of eight relative to those derived from modern observations. We also analyze Prantner’s sunspot drawings to validate our analysis of Derfflinger’s drawings. Further, we generate solar magnetograms from Derfflinger’s sunspot drawings using a deep-learning model based on conditional generative adversarial networks. Our analysis of these sunspot areas will provide important information for restoring the magnetograms during the Dalton minimum.

Despite global and local evidence of significant precipitation changes since the Little Ice Age (LIA), their impact upon lake hydrology and surrounding vegetation has yet to be investigated in NW Anatolia. Moreover, the LIA, as a trigger to the social/political recession of the Ottoman Empire in the 17th century is expected to have these impacts. To address this important gap, we studied three cores from Lake Sünnet, a landslide-dammed high altitude lake with extreme sedimentation rates, by using a wide range of proxies including lithology, stable isotopes of O and C, diatoms, pollen, and ostracods. The LIA timespan of AD 1510–1750 is represented by poorly preserved diatom flora and scarce ostracod fauna that collectively suggest very shallow aquatic conditions. The period AD 1640–1710 within the LIA is standing out with higher Abies and total herb pollen percentages that denotes considerably cooler conditions. During and soon after this cold and dry period precisely overlapping the Maunder Minimum, the currently deep Lake Sülüklü in close vicinity was a dry lowland where tall trees were growing. Progressive warming/lake level rise in Lake Sünnet after the AD 1750s is suggested based on a continuous diatom record with increasing planktonic share, increase in diverse and warm demanding arboreal cover, and a positive shift in δ18O of the lake muds. Following the relatively dry/cold period of AD 1800–1850 (Dalton Minimum) when the lake level was stationary and Artemisia cover became the most expanded of the whole record, a relatively warmer climate has dominated the area until the end of the 20th century.

Changes in the Indian Summer Monsoon during the past 600 years: A high-resolution record from the Anshupa Lake, Upper Mahanadi Delta, Core Monsoon Zone of India

The current controversy over the cause of increasing global temperatures since the middle of the 20th century comes from the IPCC First Assessment Report issued in 1990. The report states rising carbon dioxide (CO2) warms the air, thereby holding more of the significant warming gas, water vapor. This additional water vapor feeds back to amplify the warming by CO2. The IPCC has continually promoted this concept in its reports since 1990. Up-to-date science proves the IPCC concept is faulty. Scientists discovered that when the Sun's energy output changes, it impacts the Earth's temperature, and it does this cyclically. Current, reliable evidence shows the Earth has just come through a warm period. It is now in the early stages of cooling that might be similar to the Dalton Minimum and last for three or four decades. Average temperatures can drop by up to 1.5oC and increase the rate of crop failures that have already started. It won't be easy to maintain the benefits of the recent warm phase of the Sun during the upcoming solar minimum.

The concept of "Gleisberg cycle" arose from the analysis of a small amount of data for a series of Wolf numbers (WSN), which are characterized by varying degrees of reliability and with the key role of cycles 5-7 of the Dalton minimum. Back in the thirties of the last century, when analyzing the first 16 cycles was done, Gleisberg noted the frequency of their maximums in seven to eight cycles, and later gave an updated value of the period - about 80 years. In the works done over the past 60 years, this period is evaluated within 80 - 110 years. A number of researchers allocate a specific value for the Gleisberg cycle period equals to 88 years. Since different authors analyzed a series of Wolf numbers of different lengths, it makes sense to investigate the influence of the length of the series itself on this period. The paper analyzes the long-period components of WSN versions v1 and v2. The connection between the period and the length of the series is found through the sine approximation of the corresponding fragments. An increase in the sine period from 82 to 110 years (for v1) was obtained with an increase in the length of the series from 18 to 24 cycles and the conditions for the local manifestation of the 88-year harmonic. The initial periodicity of the maximums of seven to eight cycles is transformed into ten to eleven cycles. The WSN series includes recovered data from 1749 to 1849 and further on, regular observation data - reliable data. The dependence of the period on the length of the series, that is, on the share of reliable data, is associated with the inconsistency of the characteristics of the reconstructed and reliable series and casts doubt on the existence of the Gleisberg cycle or “secular” harmonic in the WSN readings in the 1749-2015 interval. changes in the land cover by temporal analysis.