scholarly journals Predictability of the 12-month Running Averaged Sunspot Number in the Presence of an 8-month Quasi-periodicity on a Solar Cycle

1990 ◽  
Vol 43 (1) ◽  
pp. 107
Author(s):  
PK Pasricha ◽  
S Aggarwal ◽  
BM Reddy ◽  
V Baskakov ◽  
OP Kolomitsev
Keyword(s):  
Solar Cycle ◽  
Sunspot Number ◽  
Statistical Significance ◽  
Sunspot Cycle ◽  
Decay Phase ◽  
Sunspot Data ◽  
One Year

The method of McNish and Lincoln (1949) for the prediction of the 12-month running averaged sunspot number R12 is supposed to generate useful estimates of R12 for periods up to one year ahead. However, it has been noted that for prediction periods beyond about 8 months, the variance of the prediction of R12 (a~12) approaches the variance of the� 'average' solar cycle. Moreover, the variance a~12 for prediction periods greater than about 8 months is also of the order of the variance (a~l) of the observed monthly-mean sunspot data RI. Since the observed sunspot data RI is used to estimate R12, the variance of RI may be used to attach statistical significance to the predictions of R12. Thus, the sunspot number RI2 cannot be usefully predicted more than 8 months ahead, because the variance of the prediction becomes too large (Le. a~12 ~ a~l). However, a quasi-periodicity of about 8 months in RI is observed during the decay phase of solar cycle 21. It is shown in this paper that the variance a~l ought to be doubled in the presence of the 8-month quasi-periodicity of the sunspot cycle. Further, by taking account of this quasi-periodicity, it is possible to make useful predictions of RI2 up to a year (and more) ahead. An application of the RI2 predictions is in forecasting the ionospheric F2 layer critical frequencies a few months ahead.

scholarly journals Overlapping Magnetic Activity Cycles and the Sunspot Number: Forecasting Sunspot Cycle 25 Amplitude

Solar Physics ◽  
2020 ◽  
Vol 295 (12) ◽  
Author(s):  
Scott W. McIntosh ◽  
Sandra Chapman ◽  
Robert J. Leamon ◽  
Ricky Egeland ◽  
Nicholas W. Watkins
Keyword(s):  
Solar Cycle ◽  
Sunspot Number ◽  
Sunspot Cycle ◽  
Periodic Variation ◽  
Magnetic Activity ◽  
The Sun ◽  
Magnetic Cycle ◽  
Hilbert Transforms ◽  
Observational Astronomy ◽  
Activity Cycles

AbstractThe Sun exhibits a well-observed modulation in the number of spots on its disk over a period of about 11 years. From the dawn of modern observational astronomy, sunspots have presented a challenge to understanding—their quasi-periodic variation in number, first noted 175 years ago, has stimulated community-wide interest to this day. A large number of techniques are able to explain the temporal landmarks, (geometric) shape, and amplitude of sunspot “cycles,” however, forecasting these features accurately in advance remains elusive. Recent observationally-motivated studies have illustrated a relationship between the Sun’s 22-year (Hale) magnetic cycle and the production of the sunspot cycle landmarks and patterns, but not the amplitude of the sunspot cycle. Using (discrete) Hilbert transforms on more than 270 years of (monthly) sunspot numbers we robustly identify the so-called “termination” events that mark the end of the previous 11-yr sunspot cycle, the enhancement/acceleration of the present cycle, and the end of 22-yr magnetic activity cycles. Using these we extract a relationship between the temporal spacing of terminators and the magnitude of sunspot cycles. Given this relationship and our prediction of a terminator event in 2020, we deduce that sunspot Solar Cycle 25 could have a magnitude that rivals the top few since records began. This outcome would be in stark contrast to the community consensus estimate of sunspot Solar Cycle 25 magnitude.

scholarly journals Prediction of solar activity cycles by assimilating sunspot data into a dynamo model

2009 ◽  
Vol 5 (S264) ◽  
pp. 202-209 ◽  
Author(s):  
Irina N. Kitiashvili ◽  
Alexander G. Kosovichev
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Solar Cycle ◽  
Sunspot Number ◽  
Magnetic Activity ◽  
Magnetic Helicity ◽  
Dynamo Model ◽  
Solar Cycles ◽  
Sunspot Data ◽  
Cycle 24

AbstractSolar activity is a determining factor for space climate of the Solar system. Thus, predicting the magnetic activity of the Sun is very important. However, our incomplete knowledge about the dynamo processes of generation and transport of magnetic fields inside Sun does not allow us to make an accurate forecast. For predicting the solar cycle properties use the Ensemble Kalman Filter (EnKF) to assimilate the sunspot data into a simple dynamo model. This method takes into account uncertainties of both the dynamo model and the observed sunspot number series. The method has been tested by calculating predictions of the past cycles using the observed annual sunspot numbers only until the start of these cycles, and showed a reasonable agreement between the predicted and actual data. After this, we have calculated a prediction for the upcoming solar cycle 24, and found that it will be approximately 30% weaker than the previous one, confirming some previous expectations. In addition, we have investigated the properties of the dynamo model during the solar minima, and their relationship to the strength of the following solar cycles. The results show that prior the weak cycles, 20 and 23, and the upcoming cycle, 24, the vector-potential of the poloidal component of magnetic field and the magnetic helicity substantial decrease. The decrease of the poloidal field corresponds to the well-known correlation between the polar magnetic field strength at the minimum and the sunspot number at the maximum. However, the correlation between the magnetic helicity and the future cycle strength is new, and should be further investigated.

Cyclic Evolution of Sunspots: Gleaning New Results from Old Data

2000 ◽  
Vol 179 ◽  
pp. 163-165
Author(s):  
S. K. Solanki ◽  
M. Fligge ◽  
P. Pulkkinen ◽  
P. Hoyng
Keyword(s):  
Sunspot Number ◽  
Sunspot Cycle ◽  
Preliminary Results ◽  
Butterfly Diagram

AbstractThe records of sunspot number, sunspot areas and sunspot locations gathered over the centuries by various observatories are reanalysed with the aim of finding as yet undiscovered connections between the different parameters of the sunspot cycle and the butterfly diagram. Preliminary results of such interrelationships are presented.

Regression Analysis of Sunspot Numbers for the Solar Cycle 24 in Comparison to Previous Three Cycles

2014 ◽  
Vol 4 (2) ◽  
pp. 477-483
Author(s):  
Debojyoti Halder
Keyword(s):  
Regression Analysis ◽  
Solar Cycle ◽  
Sunspot Number ◽  
The Sun ◽  
Sunspot Numbers ◽  
Solar Cycle 24 ◽  
Current Cycle ◽  
Cycle 24

Sunspots are temporary phenomena on the photosphere of the Sun which appear visibly as dark spots compared to surrounding regions. Sunspot populations usually rise fast but fall more slowly when observed for any particular solar cycle. The sunspot numbers for the current cycle 24 and the previous three cycles have been plotted for duration of first four years for each of them. It appears that the value of peak sunspot number for solar cycle 24 is smaller than the three preceding cycles. When regression analysis is made it exhibits a trend of slow rising phase of the cycle 24 compared to previous three cycles. Our analysis further shows that cycle 24 is approaching to a longer-period but with smaller occurrences of sunspot number.

Mid-term Periodicities in Solar Radio Emission Corresponding to Sunspot Number During Solar Cycle 23

Solar Physics ◽  
2021 ◽  
Vol 296 (3) ◽  
Author(s):  
Mahender Aroori ◽  
Panditi Vemareddy ◽  
Partha Chowdhury ◽  
Ganji Yellaiah
Keyword(s):  
Solar Cycle ◽  
Radio Emission ◽  
Sunspot Number ◽  
Solar Radio ◽  
Solar Radio Emission ◽  
Solar Cycle 23

GAIT SPEED AND HANDGRIP STRENGTH AS PREDICTORS OF INCIDENT DISABILITY IN MEXICAN OLDER ADULTS

2014 ◽  
pp. 1-4
Author(s):  
T. LOPEZ-TEROS ◽  
L.M. GUTIERREZ-ROBLEDO ◽  
M.U. PEREZ-ZEPEDA
Keyword(s):  
Older Adults ◽  
Gait Speed ◽  
Daily Living ◽  
Handgrip Strength ◽  
Statistical Significance ◽  
Adverse Outcomes ◽  
Community Dwelling ◽  
Performance Tests ◽  
One Year

Physical performance tests are associated with different adverse outcomes in older people. Theobjective of this study was to test the association between handgrip strength and gait speed with incidentdisability in community-dwelling, well-functioning, Mexican older adults (age ≥70 years). Incident disability wasdefined as the onset of any difficulty in basic or instrumental activities of daily living. Of a total of 133participants, 52.6% (n=70) experienced incident disability during one year of follow-up. Significant associationsof handgrip strength (odds ratio [OR] 0.96, 95% confidence interval [95%CI] 0.93-0.99) and gait speed (OR0.27, 95%CI 0.07-0.99) with incident disability were reported. The inclusion of covariates in the models reducedthe statistical significance of the associations without substantially modifying the magnitude of them. Handgripstrength and gait speed are independently associated with incident disability in Mexican older adults.

scholarly journals Studies on mosquitoes (Diptera: Culicidae) and anthropic environment: 1- Parity of blood seeking Anopheles (Kerteszia) in South-Eastern Brazil

1993 ◽  
Vol 27 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Oswaldo Paulo Forattini ◽  
Iná Kakitani ◽  
Eduardo Massad ◽  
Almério de Castro Gomes
Keyword(s):  
Statistical Significance ◽  
Abundant Species ◽  
Common Pattern ◽  
Host Seeking ◽  
Eastern Brazil ◽  
High Statistical Significance ◽  
Age Grading ◽  
One Year ◽  
Anopheles Cruzii ◽  
Indoor And Outdoor

Populations of Anopheles (Kerteszia) were sampled fortnightly over a one-year period (August 1991 to July 1992) at Ribeira Valley, S. Paulo State, Brazil. Indoor and outdoor collections were made on human bait at evening crepuscular period. The Polovodova technique for age grading was applied to 3,501 females of Anopheles cruzii and to 416 females of An. bellator. That sample represented 34.4% of the total number of mosquitoes collected. The most abundant species found was An. cruzii. However, An. bellator showed an endophagy that was almost three times greater than that of An. cruzii. The overall parous rate was 25.4% and uniparity was practically dominant one. A proportion of 26.9% of An. cruzii and 12.0% of An. bellator were found to be uniparous. Only three outdoor females of the former species (0.1%) showed biparity. Parity of An. cruzii was higher in females caught outdoors than in those caught indoors. Nevertheless, 497 nulliparous females examined (417 cruzii and 80 bellator) had ovaries that had advanced to Christophers and Mer stages III to V. These results imply that these females had already practised hematophagy. Relating these results to those from the parous females, a high statistical significance was found, leading to the conclusion that gonothophic discordance is a common pattern among these anophelines. Further, these results obtained with human bait catches strongly suggest that nearly 38.0% of these host-seeking females had already taken at least one previous blood-meal. So it is possible that enough time could thus be available for the plasmodian development in the vectors.

scholarly journals Seasonal, Diurnal, and Solar-Cycle Variations of Electron Density at Two West Africa Equatorial Ionization Anomaly Stations

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Frédéric Ouattara ◽  
Doua Allain Gnabahou ◽  
Christine Amory Mazaudier
Keyword(s):  
Solar Cycle ◽  
West Africa ◽  
Ultraviolet Radiation ◽  
Correlation Coefficient ◽  
Sunspot Number ◽  
Extreme Ultraviolet ◽  
Cycle Phase ◽  
Significant Variability ◽  
Equatorial Ionization Anomaly ◽  
Significant Difference

We analyse the variability of foF2 at two West Africa equatorial ionization anomaly stations (Ouagadougou and Dakar) during three solar cycles (from cycle 20 to cycle 22), that is, from 1966 to 1998 for Ouagadougou and from 1971 to 1997 for Dakar. We examine the effect of the changing levels of solar extreme ultraviolet radiation with sunspot number. The study shows high correlation between foF2 and sunspot number (Rz). The correlation coefficient decreases from cycle 20 to cycle 21 at both stations. From cycle 21 to cycle 22 it decreases at Ouagadougou station and increases at Dakar station. The best correlation coefficient, 0.990, is obtained for Dakar station during solar cycle 22. The seasonal variation displays equinoctial peaks that are asymmetric between March and September. The percentage deviations of monthly average data from one solar cycle to another display variability with respect to solar cycle phase and show solar ultraviolet radiation variability with solar cycle phase. The diurnal variation shows a noon bite out with a predominant late-afternoon peak except during the maximum phase of the solar cycle. The diurnal Ouagadougou station foF2 data do not show a significant difference between the increasing and decreasing cycle phases, while Dakar station data do show it, particularly for cycle 21. The percentage deviations of diurnal variations from solar-minimum conditions show more ionosphere during solar cycle 21 at both stations for all three of the other phases of the solar cycle. There is no significant variability of ionosphere during increasing and decreasing solar cycle phases at Ouagadougou station, but at Dakar station there is a significant variability of ionosphere during these two solar-cycle phases.

scholarly journals Composition of raw milk from conventional and organic dairy farming

2016 ◽  
Vol 32 (2) ◽  
pp. 133-143 ◽  
Author(s):  
Denis Kucevic ◽  
Snezana Trivunovic ◽  
Vladan Bogdanovic ◽  
Ksenija Cobanovic ◽  
Dobrila Jankovic ◽  
...  
Keyword(s):  
Statistical Significance ◽  
Raw Milk ◽  
Farming System ◽  
Dairy Farming ◽  
Milk Samples ◽  
High Statistical Significance ◽  
Significant Difference ◽  
Organic Dairy ◽  
One Year ◽  
The Impact

Possible differences between composition of raw milk due to dairy farming system (organic vs conventional) as well as seasonal variations were investigated. The samples were analysed during one year. A total of 6.782 samples of raw milk were collected (4.496 from organic farming). Dairy farms were located in the northern part of Republic of Serbia (Province of Vojvodina). The principle of analysis of raw milk samples was in accordance with the methodology by midinfrared spectrometry and flow cytometry. The fixed effect of system of farming and season (winter, spring, summer and fall) have shown a high statistical significance (P < 0.01) on all examined milk parameters except fat, total solids and somatic cell count, where the impact was slightly lower (P < 0.05). Significant difference wasn't found in number of bacterial colonies (P > 0.05). Composition of milk is also affected by a number of other factors, therefore it is recommended to involve factors such as nutrition of dairy cows, breed and farm management.

scholarly journals Serum Procalcitonin and C Reactive Protein in as early markers neonatal sepsis- A prospective study

2020 ◽  
Vol 8 (2) ◽  
pp. 73-77
Keyword(s):  
Blood Culture ◽  
Prospective Study ◽  
Gestational Age ◽  
Neonatal Sepsis ◽  
Statistical Significance ◽  
Developed Countries ◽  
Early Onset Sepsis ◽  
The Developed Countries ◽  
One Year ◽  
A Prospective Study

Neonatal sepsis is one of the commonest causes of morbidity and mortality in neonates in India compared to the developed countries. Aim: To evaluate the Procalcitonin level this is an early marker in the diagnosis of neonatal sepsis and to assess the suitability of this test in the diagnosis of early-onset sepsis. Method: The prospective study was conducted in the Neonatal Division of Department of Pediatrics, Prathima Institute of Medical Sciences over a period of one year. The blood samples from 100 babies meeting the inclusion and exclusion criteria constituted the material for study. Result: Among the n=100 cases n=39 were procalcitonin positive, compared with gestational age 10 (43.5%) cases were positive with a gestation of <37 weeks and 24 (31.2%) cases positive of cases >37 weeks and there was no statistical significance concerning gestational age the association of material characteristics with procalcitonin positive and CRP positive levels. Blood culture was positive in n=9 (9%) of babies with (90% CI, 5.3-14.9) and negative in n=91 (91%) of babies with (90% CI, 85.2-94.7). Conclusion: A positive blood culture is the only definitive and gold standard for confirming a case of sepsis. Since the culture and sensitivity test requires a minimum period of 48 hours which is a precious time in deciding on the treatment of sepsis in the newborn. Rapid diagnosis by using Procalcitonin and CRP gives a reasonable degree of accuracy in diagnosing neonatal sepsis and will also guide antibiotic therapy. Procalcitonin in comparison with CRP has better sensitivity and hence can detect most cases of neonatal sepsis and better negative predictive value.

Sign in / Sign up

Export Citation Format

Share Document