Defining Radiation Belt Enhancement Events Based on Probability Distributions

Abstract We present a methodology to define moderate, strong, and intense space weather events based on probability distributions. We have illustrated this methodology using a long‐duration, uniform data set of 1.8–3.5 MeV electron fluxes from multiple LANL geosynchronous satellite instruments, but...

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Main Authors: Geoffrey D. Reeves, Elizabeth M. Vandegriff, Jonathan T. Niehof, Steven K. Morley, Gregory S. Cunningham, Michael G. Henderson, Brian A. Larsen
Format: Article
Language:English
Published: Wiley 2020-08-01
Series:Space Weather
Subjects:
Online Access:https://doi.org/10.1029/2020SW002528
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author Geoffrey D. Reeves
Elizabeth M. Vandegriff
Jonathan T. Niehof
Steven K. Morley
Gregory S. Cunningham
Michael G. Henderson
Brian A. Larsen
author_facet Geoffrey D. Reeves
Elizabeth M. Vandegriff
Jonathan T. Niehof
Steven K. Morley
Gregory S. Cunningham
Michael G. Henderson
Brian A. Larsen
author_sort Geoffrey D. Reeves
collection DOAJ
description Abstract We present a methodology to define moderate, strong, and intense space weather events based on probability distributions. We have illustrated this methodology using a long‐duration, uniform data set of 1.8–3.5 MeV electron fluxes from multiple LANL geosynchronous satellite instruments, but a strength of this methodology is that it can be applied uniformly to heterogeneous data sets. It allows quantitative comparison of data sets with different energies, units, orbits, and so forth. The methodology identifies a range of times, “events,” using variable flux thresholds to determine average event occurrence in arbitrary 11‐year intervals (“cycles”). We define moderate, strong, and intense events as those that occur 100, 10, and 1 time per cycle and identify the flux thresholds that produce those occurrence frequencies. The methodology does not depend on any ancillary data set (e.g., solar wind or geomagnetic conditions). We show event probabilities using GOES > 2 MeV fluxes and compare them against event probabilities using LANL 1.8–3.5 MeV fluxes. We present some examples of how the methodology picks out moderate, strong, and intense events and how those events are distributed in time: 1989 through 2018, which includes the declining phases of solar cycles 22, 23, and 24. We also provide an illustrative comparison of moderate and strong events identified in the geosynchronous data with Van Allen Probes observations across all L‐shells. We also provide a catalog of start and stop times of moderate, strong, and intense events that can be used for future studies.
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spelling doaj-art-ea38bca7b4924e14ae2dff62a75eb9ae2025-01-14T16:27:11ZengWileySpace Weather1542-73902020-08-01188n/an/a10.1029/2020SW002528Defining Radiation Belt Enhancement Events Based on Probability DistributionsGeoffrey D. Reeves0Elizabeth M. Vandegriff1Jonathan T. Niehof2Steven K. Morley3Gregory S. Cunningham4Michael G. Henderson5Brian A. Larsen6Space Science and Applications Group Los Alamos National Laboratory Los Alamos NM USAThe New Mexico Consortium Los Alamos NM USAInstitute for the Study of Earth, Oceans, and Space University of New Hampshire Durham NH USASpace Science and Applications Group Los Alamos National Laboratory Los Alamos NM USASpace Science and Applications Group Los Alamos National Laboratory Los Alamos NM USASpace Science and Applications Group Los Alamos National Laboratory Los Alamos NM USASpace Science and Applications Group Los Alamos National Laboratory Los Alamos NM USAAbstract We present a methodology to define moderate, strong, and intense space weather events based on probability distributions. We have illustrated this methodology using a long‐duration, uniform data set of 1.8–3.5 MeV electron fluxes from multiple LANL geosynchronous satellite instruments, but a strength of this methodology is that it can be applied uniformly to heterogeneous data sets. It allows quantitative comparison of data sets with different energies, units, orbits, and so forth. The methodology identifies a range of times, “events,” using variable flux thresholds to determine average event occurrence in arbitrary 11‐year intervals (“cycles”). We define moderate, strong, and intense events as those that occur 100, 10, and 1 time per cycle and identify the flux thresholds that produce those occurrence frequencies. The methodology does not depend on any ancillary data set (e.g., solar wind or geomagnetic conditions). We show event probabilities using GOES > 2 MeV fluxes and compare them against event probabilities using LANL 1.8–3.5 MeV fluxes. We present some examples of how the methodology picks out moderate, strong, and intense events and how those events are distributed in time: 1989 through 2018, which includes the declining phases of solar cycles 22, 23, and 24. We also provide an illustrative comparison of moderate and strong events identified in the geosynchronous data with Van Allen Probes observations across all L‐shells. We also provide a catalog of start and stop times of moderate, strong, and intense events that can be used for future studies.https://doi.org/10.1029/2020SW002528radiation beltsmethodsgeosynchronousenergetic particleshazardssolar cycle
spellingShingle Geoffrey D. Reeves
Elizabeth M. Vandegriff
Jonathan T. Niehof
Steven K. Morley
Gregory S. Cunningham
Michael G. Henderson
Brian A. Larsen
Defining Radiation Belt Enhancement Events Based on Probability Distributions
Space Weather
radiation belts
methods
geosynchronous
energetic particles
hazards
solar cycle
title Defining Radiation Belt Enhancement Events Based on Probability Distributions
title_full Defining Radiation Belt Enhancement Events Based on Probability Distributions
title_fullStr Defining Radiation Belt Enhancement Events Based on Probability Distributions
title_full_unstemmed Defining Radiation Belt Enhancement Events Based on Probability Distributions
title_short Defining Radiation Belt Enhancement Events Based on Probability Distributions
title_sort defining radiation belt enhancement events based on probability distributions
topic radiation belts
methods
geosynchronous
energetic particles
hazards
solar cycle
url https://doi.org/10.1029/2020SW002528
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