scholarly journals Holocene vegetation patterns in southern Lithuania indicate astronomical forcing on the millennial and centennial time scales

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrej Spiridonov ◽  
Lauras Balakauskas ◽  
Robertas Stankevič ◽  
Gražyna Kluczynska ◽  
Laura Gedminienė ◽  
...  
Keyword(s):  
Solar Activity ◽  
Time Scales ◽  
Outer Space ◽  
Time Interval ◽  
Solar Cycles ◽  
Periodic Patterns ◽  
Physical Forcing ◽  
Compositional Diversity ◽  
Diversity Estimates

Abstract The Earth’s biota originated and developed to its current complex state through interacting with multilevel physical forcing of our planet’s climate and near and outer space phenomena. In the present study, we focus on the time scale of hundreds to thousands of years in the most recent time interval – the Holocene. Using a pollen paleocommunity dataset from southern Lithuania (Čepkeliai bog) and applying spectral analysis techniques, we tested this record for the presence of statistically significant cyclicities, which can be observed in past solar activity. The time series of non-metric multidimensional scaling (NMDS) scores, which in our case are assumed to reflect temperature variations, and Tsallis entropy-related community compositional diversity estimates q* revealed the presence of cycles on several time scales. The most consistent periodicities are characterized by periods lasting between 201 and 240 years, which is very close to the DeVries solar cycles (208 years). A shorter-term periodicity of 176 years was detected in the NMDS scores that can be putatively linked to the subharmonics of the Gleissberg solar cycle. In addition, periodicities of ≈3,760 and ≈1,880 years were found in both parameters. These periodic patterns could be explained either as originating as a harmonic nonlinear response to precession forcing, or as resulting from the long-term solar activity quasicycles that were reported in previous studies of solar activity proxies.

scholarly journals Grand minima of solar activity during the last millennia

2011 ◽  
Vol 7 (S286) ◽  
pp. 372-382 ◽  
Author(s):  
Ilya G. Usoskin ◽  
Sami K. Solanki ◽  
Gennady A. Kovaltsov
Keyword(s):  
Solar Activity ◽  
Historical Record ◽  
Moderate Activity ◽  
Solar Cycles ◽  
Cosmogenic Isotope ◽  
Cyclic Variations ◽  
Grand Maximum ◽  
Grand Minima ◽  
Stellar Dynamo

AbstractIn this review we discuss the occurrence and statistical properties of Grand minima based on the available data covering the last millennia. In particular, we consider the historical record of sunspot numbers covering the last 400 years as well as records of cosmogenic isotopes in natural terrestrial archives, used to reconstruct solar activity for up to the last 11.5 millennia, i.e. throughout the Holocene. Using a reconstruction of solar activity from cosmogenic isotope data, we analyze statistics of the occurrence of Grand minima. We find that: the Sun spends about most of the time at moderate activity, 1/6 in a Grand minimum and some time also in a Grand maximum state; Occurrence of Grand minima is not a result of long-term cyclic variations but is defined by stochastic/chaotic processes; There is a tendency for Grand minima to cluster with the recurrence rate of roughly 2000-3000 years, with a weak ≈210-yr periodicity existing within the clusters. Grand minima occur of two different types: shorter than 100 years (Maunder-type) and long ≈150 years (Spörer-type). It is also discussed that solar cycles (most possibly not sunspots cycle) could exist during the Grand minima, perhaps with stretched length and asymmetric sunspot latitudinal distribution.These results set new observational constraints on long-term solar and stellar dynamo models.

scholarly journals Long-term variations of the mesospheric wind field at mid-latitudes

2007 ◽  
Vol 25 (8) ◽  
pp. 1779-1790 ◽  
Author(s):  
D. Keuer ◽  
P. Hoffmann ◽  
W. Singer ◽  
J. Bremer
Keyword(s):  
Solar Activity ◽  
Wind Field ◽  
Meridional Wind ◽  
Time Interval ◽  
Wind Component ◽  
Model Calculations ◽  
Measuring Techniques ◽  
Long Term Trends ◽  
Solar Influence

Abstract. Continuous MF radar observations at the station Juliusruh (54.6° N; 13.4° E) have been analysed for the time interval between 1990 and 2005, to obtain information about solar activity-induced variations, as well as long-term trends in the mesospheric wind field. Using monthly median values of the zonal and the meridional prevailing wind components, as well as of the amplitude of the semidiurnal tide, regression analyses have been carried out with a dependence on solar activity and time. The solar activity causes a significant amplification of the zonal winds during summer (increasing easterly winds) and winter (increasing westerly winds). The meridional wind component is positively correlated with the solar activity during summer but during winter the correlation is very small and non significant. Also, the solar influence upon the amplitude of the semidiurnal tidal component is relatively small (in dependence on height partly positive and partly negative) and mostly non-significant. The derived trends in the zonal wind component during summer are below an altitude of about 83 km negative and above this height positive. During the winter months the trends are nearly opposite compared with the trends in summer (transition height near 86 km). The trends in the meridional wind components are below about 85 km positive in summer (significant) and near zero (nonsignificant) in winter; above this height during both seasons negative trends have been detected. The trends in the semidiurnal tidal amplitude are at all heights positive, but only partly significant. The detected trends and solar cycle dependencies are compared with other experimental results and model calculations. There is no full agreement between the different results, probably caused by different measuring techniques and evaluation methods used. Also, different heights and observation periods investigated may contribute to the detected differences.

High solar activity predictions through an artificial neural network

2017 ◽  
Vol 28 (06) ◽  
pp. 1750075 ◽  
Author(s):  
M. G. Orozco-Del-Castillo ◽  
J. C. Ortiz-Alemán ◽  
C. Couder-Castañeda ◽  
J. J. Hernández-Gómez ◽  
A. Solís-Santomé
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Solar Activity ◽  
Outer Space ◽  
High Energy ◽  
High Solar Activity ◽  
Solar Cycles ◽  
The Neural Network ◽  
Space Electronics ◽  
Artificial Neural

The effects of high-energy particles coming from the Sun on human health as well as in the integrity of outer space electronics make the prediction of periods of high solar activity (HSA) a task of significant importance. Since periodicities in solar indexes have been identified, long-term predictions can be achieved. In this paper, we present a method based on an artificial neural network to find a pattern in some harmonics which represent such periodicities. We used data from 1973 to 2010 to train the neural network, and different historical data for its validation. We also used the neural network along with a statistical analysis of its performance with known data to predict periods of HSA with different confidence intervals according to the three-sigma rule associated with solar cycles 24–26, which we found to occur before 2040.

Periodic Variation of the North-South Asymmetry of Solar Activity Phenomena

2000 ◽  
Vol 179 ◽  
pp. 173-176
Author(s):  
V. K. Verma
Keyword(s):  
Solar Activity ◽  
Periodic Variation ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
Sunspot Data ◽  
Flare Index ◽  
North And South ◽  
South Asymmetry

AbstractWe report here a study of various solar activity phenomena occurring in both north and south hemispheres of the Sun during solar cycles 8–23. In the study we have used sunspot data for the period 1832–1976, flare index data for the period 1936–1993, Hα flare data 1993–1998 and solar active prominences data for the period 1957–1998. Earlier Verma reported long-term cyclic period in N-S asymmetry and also that the N-S asymmetry of solar activity phenomena during solar cycles 21, 22, 23 and 24 will be south dominated and the N-S asymmetry will shift to north hemisphere in solar cycle 25. The present study shows that the N-S asymmetry during solar cycles 22 and 23 are southern dominated as suggested by Verma.

Nonlinear Prediction of Solar Cycle 25

2018 ◽  
Vol 13 (S340) ◽  
pp. 321-322
Author(s):  
Volkan Sarp ◽  
Ali Kılçık
Keyword(s):  
Solar Activity ◽  
Sunspot Number ◽  
Prediction Method ◽  
Solar Cycles ◽  
Nonlinear Prediction ◽  
Cycle 24 ◽  
And Performance ◽  
Prediction Approach ◽  
Good Agreement

AbstractSolar activity is a chaotic process and there are various approximations to forecast its long term and short term variations. But there is no prediction method that predicts the solar activity exactly. In this study, a nonlinear prediction approach was applied to international sunspot numbers and performance of predictions was tested for the last 5 solar cycles. These predictions are in good agreement with observed values of the tested solar cycles. According to these results, end of cycle 24 is expected at February, 2020 with 7.7 smoothed monthly mean sunspot number and maximum of cyle 25 is expected at May, 2024 with 119.6 smoothed monthly mean sunspot number.

Irradiance Observations of the Sun

1994 ◽  
Vol 143 ◽  
pp. 28-36 ◽  
Author(s):  
Claus Fröhlich
Keyword(s):  
Solar Activity ◽  
Time Scales ◽  
Solar Maximum ◽  
Activity Cycle ◽  
Total Solar Irradiance ◽  
The Sun ◽  
Direct Influence ◽  
Magnetic Network ◽  
Over Time

Measurements of the total solar irradiance during the last 14 years from satellites show variations over time scales from minutes to years and decades. The most important variance is in the range from days to several months and is related to the photospheric features of solar activity: decreasing the irradiance during the appearance of sunspots, and increasing it by faculae and the bright magnetic network. Long-term modulation by the 11-year activity cycle is observed conclusively with the irradiance being higher during solar maximum. The accuracy of the determined variability and its interpretation in terms of manifestations of activity related features on the photosphere is discussed. Besides the direct influence of the spots, faculae and magnetic network more profound changes in the thermal transport seem to influence the behaviour of the solar photospheric radiation on the solar cycle and longer time scales.

A Study of Long-Term Solar Activity at 37 GHz

2012 ◽  
Vol 21 (3) ◽  
Author(s):  
J. Kallunki ◽  
N. Lavonen ◽  
E. Järvelä ◽  
M. Uunila
Keyword(s):  
Solar Activity ◽  
Solar Radio ◽  
Data Series ◽  
Public Knowledge ◽  
Solar Cycles ◽  
Data Set ◽  
Radio Observatory ◽  
The Public ◽  
Radio Map

AbstractIn this paper we investigate the solar activity at the radio frequency (37 GHz) using an extensive data series (solar radio maps) from the Metsähovi Radio Observatory. This paper aims to present this unique solar radio map collection to the public knowledge. The data set covers the years from 1978 to 2011 (solar cycles 21–24). We investigate the long-term solar activity on the ground of the distribution of solar radio brightenings and the differential rotation of the Sun.

scholarly journals Long-term dynamics of OH * temperatures over central Europe: trends and solar correlations

2016 ◽  
Vol 16 (23) ◽  
pp. 15033-15047 ◽  
Author(s):  
Christoph Kalicinsky ◽  
Peter Knieling ◽  
Ralf Koppmann ◽  
Dirk Offermann ◽  
Wolfgang Steinbrecht ◽  
...  
Keyword(s):  
Time Series ◽  
Solar Activity ◽  
Solar Radio ◽  
Linear Trend ◽  
Temperature Time Series ◽  
Time Interval ◽  
Radio Flux ◽  
Solar Radio Flux ◽  
Temperature Time

Abstract. We present the analysis of annual average OH* temperatures in the mesopause region derived from measurements of the Ground-based Infrared P-branch Spectrometer (GRIPS) at Wuppertal (51° N, 7° E) in the time interval 1988 to 2015. The new study uses a temperature time series which is 7 years longer than that used for the latest analysis regarding the long-term dynamics. This additional observation time leads to a change in characterisation of the observed long-term dynamics. We perform a multiple linear regression using the solar radio flux F10.7 cm (11-year cycle of solar activity) and time to describe the temperature evolution. The analysis leads to a linear trend of (−0.089 ± 0.055) K year−1 and a sensitivity to the solar activity of (4.2 ± 0.9) K (100 SFU)−1 (r2 of fit 0.6). However, one linear trend in combination with the 11-year solar cycle is not sufficient to explain all observed long-term dynamics. In fact, we find a clear trend break in the temperature time series in the middle of 2008. Before this break point there is an explicit negative linear trend of (−0.24 ± 0.07) K year−1, and after 2008 the linear trend turns positive with a value of (0.64 ± 0.33) K year−1. This apparent trend break can also be described using a long periodic oscillation. One possibility is to use the 22-year solar cycle that describes the reversal of the solar magnetic field (Hale cycle). A multiple linear regression using the solar radio flux and the solar polar magnetic field as parameters leads to the regression coefficients Csolar = (5.0 ± 0.7) K (100 SFU)−1 and Chale = (1.8 ±  0.5) K (100 µT)−1 (r2 = 0.71). The second way of describing the OH* temperature time series is to use the solar radio flux and an oscillation. A least-square fit leads to a sensitivity to the solar activity of (4.1 ± 0.8) K (100 SFU)−1, a period P  =  (24.8 ± 3.3) years, and an amplitude Csin  =  (1.95 ± 0.44) K of the oscillation (r2 = 0.78). The most important finding here is that using this description an additional linear trend is no longer needed. Moreover, with the knowledge of this 25-year oscillation the linear trends derived in this and in a former study of the Wuppertal data series can be reproduced by just fitting a line to the corresponding part (time interval) of the oscillation. This actually means that, depending on the analysed time interval, completely different linear trends with respect to magnitude and sign can be observed. This fact is of essential importance for any comparison between different observations and model simulations.

scholarly journals Long-term correlations in solar proxies and solar wind parameters

2021 ◽  
Author(s):  
Luca Giovannelli ◽  
Raffaele Reda ◽  
Tommaso Alberti ◽  
Francesco Berrilli ◽  
Matteo Cantoresi ◽  
...  
Keyword(s):  
Solar Wind ◽  
Time Lag ◽  
Magnetic Activity ◽  
Time Shift ◽  
Time Interval ◽  
Solar Cycles ◽  
K Index ◽  
The Earth ◽  
Solar Wind Parameters

<p>The long-term behaviour of the Solar wind and its impact on the Earth are of paramount importance to understand the framework of the strong transient perturbations (CMEs, SIRs). Solar variability related to its magnetic activity can be quantified by using synthetic indices (e.g. sunspots number) or physical ones (e.g. chromospheric proxies). In order to connect the long-term solar activity variations to solar wind properties, we use Ca II K index and solar wind OMNI data in the time interval between 1965 and 2019, which almost entirely cover the last 5 solar cycles. A time lag in the correlation between the parameters is found. This time shift seems to show a temporal evolution over the different solar cycles.</p><div> </div>

scholarly journals Solar modulation of flood frequency in Central Europe during spring and summer on inter-annual to millennial time-scales

2015 ◽  
Vol 11 (5) ◽  
pp. 4833-4850 ◽  
Author(s):  
M. Czymzik ◽  
R. Muscheler ◽  
A. Brauer
Keyword(s):  
Solar Activity ◽  
Central Europe ◽  
Time Scales ◽  
Decadal Variability ◽  
Empirical Support ◽  
Flood Frequency ◽  
Solar Modulation ◽  
Solar Cycles ◽  
Discharge Data ◽  
Discharge Record

Abstract. Solar influences on climate variability are one of the most controversially discussed topics in climate research. We analyze solar forcing of flood frequency in Central Europe on inter-annual to millennial time-scales using daily discharge data of River Ammer (southern Germany) back to AD 1926 and revisiting the 5500 year flood layer time-series from varved sediments of the downstream Lake Ammersee. Flood frequency in the discharge record is significantly correlated to changes in solar activity during solar cycles 16–23 (r = −0.47, p < 0.0001, n = 73). Flood layer frequency (n = 1501) in the sediment record depicts distinct multi-decadal variability and significant correlations to 10Be fluxes from a Greenland ice core (r = 0.45, p < 0.0001) and 14C production rates (r =0.36, p < 0.0001), proxy records of solar activity. Flood frequency is higher when solar activity is reduced. These correlations between flood frequency and solar activity might provide empirical support for the solar top-down mechanism expected to modify the mid-latitude storm tracks over Europe by model studies. A lag of flood frequency responses in the Ammer discharge record to changes in solar activity of about one to three years could be explained by a modelled ocean–atmosphere feedback delaying the atmospheric reaction to solar activity variations up to a few years.

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