scholarly journals Evaluation of the UMASEP-10 Version 2 Tool for Predicting All >10 MeV SEP Events of Solar Cycles 22, 23 and 24

Universe ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 35
Author(s):  
Marlon Núñez
Keyword(s):  
Solar Energetic Particle ◽  
Probability Of Detection ◽  
Dual Model ◽  
Solar Cycles ◽  
Correlation Algorithm ◽  
Proton Fluxes ◽  
Model Scheme ◽  
Cycle 24 ◽  
Warning Time ◽  
Model Approach

The prediction of solar energetic particle (SEP) events may help to improve the mitigation of adverse effects on humans and technology in space. UMASEP (University of Málaga Solar particle Event Predictor) is an empirical model scheme that predicts SEP events. This scheme is based on a dual-model approach. The first model predicts well-connected events by using an improved lag-correlation algorithm for analyzing soft X-ray (SXR) and differential proton fluxes to estimate empirically the Sun–Earth magnetic connectivity. The second model predicts poorly connected events by analyzing the evolution of differential proton fluxes. This study presents the evaluation of UMASEP-10 version 2, a tool based on the aforementioned scheme for predicting all >10 MeV SEP events, including those without associated flare. The evaluation of this tool is presented in terms of the probability of detection (POD), false alarm ratio (FAR) and average warning time (AWT). The best performance was achieved for the solar cycle 24 (i.e., 2008–2019), obtaining a POD of 91.1% (41/45), a FAR of 12.8% (6/47) and an AWT of 2 h 46 min. These results show that UMASEP-10 version 2 obtains a high POD and low FAR mainly because it is able to detect true Sun–Earth magnetic connections.

scholarly journals SEQUENCE-BASED PREDICTION OF PROTEIN B-FACTORS WITH DUAL SUPERVIZED LEARNING MODELS

2010 ◽  
Vol 22 (05) ◽  
pp. 385-391
Author(s):  
Yu-Cheng Liu ◽  
Shien-Ching Hwang ◽  
Yu-Feng Huang ◽  
Win-Li Lin ◽  
Yen-Jen Oyang ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Prediction Accuracy ◽  
Active Sites ◽  
Pearson Correlation ◽  
Experimental Results ◽  
Structural Flexibility ◽  
Dual Model ◽  
Functional Sites ◽  
High Degree ◽  
Model Approach

The B-factor, which is also known as temperature factor or Debby–Waller factor, is an important structural flexibility index of the ground-state protein conformation. In particular, the B-factors associated with a segment of residues, reflect the local flexibility of the corresponding protein tertiary substructure. Recent studies have shown that, for certain families of proteins, there exists a high-degree of correlation between the B-factors and the protein functional sites, including antigenic regions, enzyme active sites, and nucleotide binding sites. This paper presents a sequence–based predictor of B-factors with a dual-model approach.  The design of the dual-model approach has been aimed at exploiting the bi-modal distribution of B-factors in order to achieve higher prediction accuracy. In this paper, the prediction accuracy is measured by Pearson correlation coefficient. Experimental results show that the dual-model predictor proposed in this article is capable of delivering superior correlation coefficient in comparison with two predictors reported in two latest papers.  Though experimental results show that the dual-model proposed in this paper really works more effectively than the conventional approach, it is of interest to continue investigating more advanced designs since there exists a strong correlation between B-factors and protein functional sites. In this respect, identifying additional physiochemical properties that are related to structural flexibility deserves a high-degree of attention.

scholarly journals Shock Connectivity and the Late Cycle 24 Solar Energetic Particle Events in July and September 2017

Space Weather ◽  
2018 ◽  
Vol 16 (5) ◽  
pp. 557-568 ◽  
Author(s):  
J. G. Luhmann ◽  
M. L. Mays ◽  
Yan Li ◽  
C. O. Lee ◽  
H. Bain ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Solar Energetic Particle ◽  
Solar Energetic Particle Events ◽  
Cycle 24

scholarly journals Solar Activity and Svalbard Temperatures

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Jan-Erik Solheim ◽  
Kjell Stordahl ◽  
Ole Humlum
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Winter Temperature ◽  
Positive Trend ◽  
Seasonal Temperature ◽  
Solar Cycles ◽  
Temperature Variations ◽  
Mean Temperature ◽  
Cent Level ◽  
Cycle 24

The long temperature series at Svalbard (Longyearbyen) show large variations and a positive trend since its start in 1912. During this period solar activity has increased, as indicated by shorter solar cycles. The temperature at Svalbard is negatively correlated with the length of the solar cycle. The strongest negative correlation is found with lags 10–12 years. The relations between the length of a solar cycle and the mean temperature in the following cycle are used to model Svalbard annual mean temperature and seasonal temperature variations. Residuals from the annual and winter models show no autocorrelations on the 5 per cent level, which indicates that no additional parameters are needed to explain the temperature variations with 95 per cent significance. These models show that 60 per cent of the annual and winter temperature variations are explained by solar activity. For the spring, summer, and fall temperatures autocorrelations in the residuals exist, and additional variables may contribute to the variations. These models can be applied as forecasting models. We predict an annual mean temperature decrease for Svalbard of °C from solar cycle 23 to solar cycle 24 (2009–20) and a decrease in the winter temperature of °C.

scholarly journals Super-active regions in solar cycle 24

2015 ◽  
Vol 11 (S320) ◽  
pp. 309-314 ◽  
Author(s):  
Anqin Chen ◽  
Jingxiu Wang
Keyword(s):  
Solar Cycle ◽  
Active Regions ◽  
Total Solar Irradiance ◽  
Flare Activity ◽  
Solar Cycles ◽  
Solar Cycle 24 ◽  
Satisfactory Account ◽  
Current Cycle ◽  
Flare Index ◽  
Cycle 24

AbstractComparing with solar cycles 21-23, the level of solar activity in the current cycle is very low. So far, there have been only five SARs and 45 X class flares. The monthly smoothed total solar irradiance decreased sharply by 0.09% from the maximum of cycle 23 to the minima between cycles 23 and 24. In this contribution, we present new studies on SARs in Cycle 24. The SARs in the current cycle have relatively smaller flare index (Iflare) and composite vector field index (Icom) comparing with the SARs in cycles 22 and 23. There is a clearly linear relationship between Iflare and Icom. The emphasis of this contribution is put on the similarity and different behaviors of vector magnetic fields of the SARs in the current solar cycle and the previous ones. We try to get a satisfactory account for the general characteristics and relatively lower level of solar flare activity in Cycle 24.

Solar flares, CMEs and solar energetic particle events during solar cycle 24

2018 ◽  
Vol 61 (2) ◽  
pp. 777-785 ◽  
Author(s):  
Bimal Pande ◽  
Seema Pande ◽  
Ramesh Chandra ◽  
Mahesh Chandra Mathpal
Keyword(s):  
Solar Cycle ◽  
Solar Flares ◽  
Energetic Particle ◽  
Solar Energetic Particle ◽  
Solar Energetic Particle Events ◽  
Solar Cycle 24 ◽  
Cycle 24

Solar energetic particle events during the rise phases of solar cycles 23 and 24

2013 ◽  
Vol 52 (12) ◽  
pp. 2102-2111 ◽  
Author(s):  
R. Chandra ◽  
N. Gopalswamy ◽  
P. Mäkelä ◽  
H. Xie ◽  
S. Yashiro ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Solar Energetic Particle ◽  
Solar Cycles ◽  
Solar Energetic Particle Events

scholarly journals Photospheric activity of the Sun with VIRGO and GOLF

2017 ◽  
Vol 608 ◽  
pp. A87 ◽  
Author(s):  
D. Salabert ◽  
R. A. García ◽  
A. Jiménez ◽  
L. Bertello ◽  
E. Corsaro ◽  
...  
Keyword(s):  
Solar Activity ◽  
Radial Velocity ◽  
Wavelength Dependence ◽  
Solar Photosphere ◽  
The Sun ◽  
Solar Cycles ◽  
Quasi Biennial Oscillation ◽  
Photometric Observations ◽  
Cycle 24 ◽  
Biennial Oscillation

We study the variability of solar activity using new photospheric proxies originally developed for the analysis of stellar magnetism with the CoRoT and Kepler photometric observations. These proxies were obtained by tracking the temporal modulations in the observations associated with the spots and magnetic features as the Sun rotates. We analyzed 21 yr of observations, spanning solar cycles 23 and 24, collected by the space-based photometric VIRGO and radial velocity GOLF instruments on board the SoHO satellite. We then calculated the photospheric activity proxy Sph is for each of the three VIRGO photometers and the associated Svel proxy from the radial velocity GOLF observations. Comparisons with several standard solar activity proxies sensitive to different layers of the Sun demonstrate that these new activity proxies, Sph and Svel, provide a new manner to monitor solar activity. We show that both the long- and short-term magnetic variabilities respectively associated with the 11-yr cycle and the quasi-biennial oscillation are well monitored, and that the magnetic field interaction between the subsurface, photosphere, and chromosphere of the Sun was modified between Cycle 24 and Cycle 23. Furthermore, the photometric proxies show a wavelength dependence of the response function of the solar photosphere among the three channels of the VIRGO photometers, providing inputs for the study of the stellar magnetism of Sun-like stars.

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