An Objective Baseline For Flare Prediction

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An Objective Baseline For Flare Prediction

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Author : Ronald T. Podsiadlo
language : en
Publisher:
Release Date : 1972

An Objective Baseline For Flare Prediction written by Ronald T. Podsiadlo and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1972 with Correlation (Statistics) categories.

The relationship between various measurable solar parameters and solar-flare occurrence is examined utilizing a comprehensive solar-geophysical data base containing a variety of objectively-correlated solar measurements. The sample covers the period from January 1955 through February 1968 and includes such parameters as solar flares, sunspots, magnetic fields of sunspots, calcium plages and 9.1 cm radio brightness temperatures. A statistical analysis was performed to determine the parameters most useful for the prediction of solar flares 24 hours in advance. Persistence was identified as the single most important flare predictor, with sunspot magnetic classification, 9.1 cm radio brightness temperature, plage brightness and sunspot area also selected as useful predictors. Objective flare probability prediction equations were developed that incorporate all useful predictors simultaneously. (Author).

An Objective Baseline For Flare Prediction

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Author : Ronald T. Podsiadlo
language : en
Publisher:
Release Date : 1972

An Objective Baseline For Flare Prediction written by Ronald T. Podsiadlo and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1972 with Correlation (Statistics) categories.

The relationship between various measurable solar parameters and solar-flare occurrence is examined utilizing a comprehensive solar-geophysical data base containing a variety of objectively-correlated solar measurements. The sample covers the period from January 1955 through February 1968 and includes such parameters as solar flares, sunspots, magnetic fields of sunspots, calcium plages and 9.1 cm radio brightness temperatures. A statistical analysis was performed to determine the parameters most useful for the prediction of solar flares 24 hours in advance. Persistence was identified as the single most important flare predictor, with sunspot magnetic classification, 9.1 cm radio brightness temperature, plage brightness and sunspot area also selected as useful predictors. Objective flare probability prediction equations were developed that incorporate all useful predictors simultaneously. (Author)

Environmental Research Papers

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Author :
language : en
Publisher:
Release Date : 1972

Environmental Research Papers written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1972 with Environmental geology categories.

Feature Selection Flaring Size And Time To Flare Prediction Using Support Vector Regression And Automated Prediction Of Flaring Behavior Based On Spatio Temporal Measures Using Hidden Markov Models

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Author : Amani M. Al-Ghraibah
language : en
Publisher:
Release Date : 2015

Feature Selection Flaring Size And Time To Flare Prediction Using Support Vector Regression And Automated Prediction Of Flaring Behavior Based On Spatio Temporal Measures Using Hidden Markov Models written by Amani M. Al-Ghraibah and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Solar flares categories.

Solar flares release stored magnetic energy in the form of radiation and can have significant detrimental effects on earth including damage to technological infrastructure. Recent work has considered methods to predict future flare activity on the basis of quantitative measures of the solar magnetic field. Accurate advanced warning of solar flare occurrence is an area of increasing concern and much research is ongoing in this area. Our previous work [11] utilized standard pattern recognition and classification techniques to determine (classify) whether a region is expected to flare within a predictive time window, using a Relevance Vector Machine (RVM) classification method. We extracted 38 features which describing the complexity of the photospheric magnetic field, the result classification metrics will provide the baseline against which we compare our new work. We find true positive rate (TPR) of 0.8, true negative rate (TNR) of 0.7, and true skill score (TSS) of 0.49. This dissertation proposes three basic topics; the first topic is an extension to our previous work [11], where we consider a feature selection method to determine an appropriate feature subset with cross validation classification based on a histogram analysis of selected features. Classification using the top five features resulting from this analysis yield better classification accuracies across a large unbalanced dataset. In particular, the feature subsets provide better discrimination of the many regions that flare where we find a TPR of 0.85, a TNR of 0.65 sightly lower than our previous work, and a TSS of 0.5 which has an improvement comparing with our previous work. In the second topic, we study the prediction of solar flare size and time-to-flare using support vector regression (SVR). When we consider flaring regions only, we find an average error in estimating flare size of approximately half a GOES class. When we additionally consider non-flaring regions, we find an increased average error of approximately 3/4 a GOES class. We also consider thresholding the regressed flare size for the experiment containing both flaring and non-flaring regions and find a TPR of 0.69 and a TNR of 0.86 for flare prediction, consistent with our previous studies of flare prediction using the same magnetic complexity features. The results for both of these size regression experiments are consistent across a wide range of predictive time windows, indicating that the magnetic complexity features may be persistent in appearance long before flare activity. This conjecture is supported by our larger error rates of some 40 hours in the time-to-flare regression problem. The magnetic complexity features considered here appear to have discriminative potential for flare size, but their persistence in time makes them less discriminative for the time-to-flare problem. We also study the prediction of solar flare size and time-to-flare using two temporal features, namely the [delta]- and [delta-delta-]features, the same average size and time-to-flare regression error are found when these temporal features are used in size and time-to-flare prediction. In the third topic, we study the temporal evolution of active region magnetic fields using Hidden Markov Models (HMMs) which is one of the efficient temporal analyses found in literature. We extracted 38 features which describing the complexity of the photospheric magnetic field. These features are converted into a sequence of symbols using k-nearest neighbor search method. We study many parameters before prediction; like the length of the training window W[subscript train] which denotes to the number of history images use to train the flare and non-flare HMMs, and number of hidden states Q. In training phase, the model parameters of the HMM of each category are optimized so as to best describe the training symbol sequences. In testing phase, we use the best flare and non-flare models to predict/classify active regions as a flaring or non-flaring region using a sliding window method. The best prediction result is found where the length of the history training images are 15 images (i.e., W[subscript train]= 15) and the length of the sliding testing window is less than or equal to W[subscript train], the best result give a TPR of 0.79 consistent with previous flare prediction work, TNR of 0.87 and TSS of 0.66, where both are higher than our previous flare prediction work. We find that the best number of hidden states which can describe the temporal evolution of the solar ARs is equal to five states, at the same time, a close resultant metrics are found using different number of states.

Scientific And Technical Aerospace Reports

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Author :
language : en
Publisher:
Release Date : 1994

Scientific And Technical Aerospace Reports written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994 with Aeronautics categories.

Nuclear Science Abstracts

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Author :
language : en
Publisher:
Release Date : 1974

Nuclear Science Abstracts written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1974 with Nuclear energy categories.

Solar Terrestrial Predictions Proceedings Solar Activity Predictions

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Author : Richard Frank Donnelly
language : en
Publisher:
Release Date : 1979

Solar Terrestrial Predictions Proceedings Solar Activity Predictions written by Richard Frank Donnelly and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1979 with Geophysics categories.

Solar Terrestrial Predictions Proceedings Prediction Group Reports

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Author : Richard Frank Donnelly
language : en
Publisher:
Release Date : 1979

Solar Terrestrial Predictions Proceedings Prediction Group Reports written by Richard Frank Donnelly and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1979 with Ionospheric forecasting categories.

Effect Of The Ionosphere On Space And Terrestrial Systems

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Author :
language : en
Publisher:
Release Date : 1978

Effect Of The Ionosphere On Space And Terrestrial Systems written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1978 with Artificial satellites categories.

Solar Terrestrial Predictions Proceedings

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Author : Richard Frank Donnelly
language : en
Publisher:
Release Date : 1979

Solar Terrestrial Predictions Proceedings written by Richard Frank Donnelly and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1979 with Cosmic physics categories.