Download or read book An Objective Baseline for Flare Prediction written by Ronald T. Podsiadlo and published by . This book was released on 1972 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).
Download or read book An Objective Baseline for Flare Prediction written by Ronald T. Podsiadlo and published by . This book was released on 1972 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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)
Download or read book Environmental Research Papers written by and published by . This book was released on 1972 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1974 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar terrestrial Predictions Proceedings Prediction group reports written by Richard Frank Donnelly and published by . This book was released on 1979 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar terrestrial Predictions Proceedings Solar activity predictions written by Richard Frank Donnelly and published by . This book was released on 1979 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar terrestrial Predictions Proceedings written by Richard Frank Donnelly and published by . This book was released on 1979 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 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 published by . This book was released on 2015 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Effect of the Ionosphere on Space and Terrestrial Systems written by and published by . This book was released on 1978 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Flare Prediction written by C. Sawyer and published by . This book was released on 1986 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study looked at observational and theoretical studies of flare physics, at quests for flare precursors, and at mathematical models for combining masses of predictive information. We also looked at the worldwide effort to gather and share timely data and combine it with knowledge and experience to forecast solar flares and their effects. Topics include: Long-lived, large-scale magnetic and velocity fields; Magnetic-energy buildup in an active region; Flare initiation; Flare precursors -- Filament activation, Preflare brightening, Magnetic shear, and Emerging and cancelling magnetic flux; Quantitative prediction; Operational solar flare prediction; Forecast evaluation.
Download or read book Solar activity reports written by Richard Frank Donnelly and published by . This book was released on 1979 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Flare Prediction written by Sawyer C. and published by . This book was released on with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Report on Research at AFCRL written by Air Force Cambridge Research Laboratories (U.S.) and published by . This book was released on 1972 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sixth Conference on Probability and Statistics in Atmospheric Sciences of the American Meteorological Society October 9 12 1979 Banff Alta Canada written by and published by . This book was released on 1979 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Index written by and published by . This book was released on 1972 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography with Abstracts of AFCRL Publications from 1 July to 30 September 1972 written by Air Force Cambridge Research Laboratories (U.S.) and published by . This book was released on 1972 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: This bibliography lists all AFCRL in-house reports, journal articles, and contractor reports issued during the reporting period. The DD Form 1473 (Document Control Data - R & D) for each publication is included. In Part I, the 1473's for in-house reports are arranged numerically by the series in which they were issued: in Part II, the 1473's for journal articles are arranged alphabetically by author; in Part III, the 1473's for contractor reports are arranged alphabetically by corporate author. For cross-reference purposes, an index is included, listing the publications numerically by the AFCRL document number.
