scholarly journals Spectral Analyses and Radiation Exposures from Several Ground-Level Enhancement (GLE) Solar Proton Events: A Comparison of Methodologies

2011 ◽  
Author(s):  
William Atwell ◽  
Allan Tylka ◽  
William Dietrich ◽  
Francis Badavi ◽  
Kristina Rojdev
Keyword(s):  
Ground Level ◽  
Solar Proton ◽  
Ground Level Enhancement ◽  
Spectral Analyses ◽  
Solar Proton Events

scholarly journals Northern Hemisphere atmospheric influence of the solar proton events and ground level enhancement in January 2005

2011 ◽  
Vol 11 (3) ◽  
pp. 7715-7755 ◽  
Author(s):  
C. H. Jackman ◽  
D. R. Marsh ◽  
F. M. Vitt ◽  
R. G. Roble ◽  
C. E. Randall ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Atmospheric Chemistry ◽  
Reasonable Agreement ◽  
Climate Model ◽  
Michelson Interferometer ◽  
Ground Level ◽  
Solar Proton ◽  
Ground Level Enhancement ◽  
Time Period ◽  
Solar Proton Events

Abstract. Solar eruptions in early 2005 led to a substantial barrage of charged particles on the Earth's atmosphere during the 16–21 January period. Proton fluxes were greatly increased during these several days and led to the production of HOx (H, OH, HO2) and NOx (N, NO, NO2), which then caused the destruction of ozone. We focus on the Northern polar region, where satellite measurements and simulations with the Whole Atmosphere Community Climate Model (WACCM3) showed large enhancements in mesospheric HOx and NOx constituents, and associated ozone reductions, due to these solar proton events (SPEs). The WACCM3 simulations show enhanced short-lived OH throughout the mesosphere in the 60–82.5° N latitude band due to the SPEs for most days in the 16–21 January 2005 period, in reasonable agreement with the Aura Microwave Limb Sounder (MLS) measurements. Mesospheric HO2 is also predicted to be increased by the SPEs, however, the modeled HO2 results are somewhat larger than the MLS measurements. These HOx enhancements led to huge predicted and MLS-measured ozone decreases of greater than 40% throughout most of the northern polar mesosphere during the SPE period. Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) measurements of hydrogen peroxide (H2O2) show increases throughout the stratosphere with highest enhancements of about 60 pptv in the lowermost mesosphere over the 16–18 January 2005 period due to the solar protons. WACCM3 predictions indicate H2O2 enhancements over the same time period of more than twice that amount. Measurements of nitric acid (HNO3) by both MLS and MIPAS show an increase of about 1 ppbv above background levels in the upper stratosphere during 16–29 January 2005. WACCM3 simulations show only minuscule HNO3 changes in the upper stratosphere during this time period. Polar mesospheric enhancements of NOx are computed to be greater than 50 ppbv during the SPE period due to the small loss rates during winter. Computed NOx increases, which were statistically significant at the 95% level, lasted about a month past the SPEs. The SCISAT-1 Atmospheric Chemistry Experiment Fourier Transform Spectrometer NOx measurements and MIPAS NO2 measurements for the polar Northern Hemisphere are in reasonable agreement with these predictions. An extremely large ground level enhancement (GLE) occurred during the SPE period on 20 January 2005. We find that protons of energies 300 to 20 000 MeV, not normally included in our computations, led to enhanced lower stratospheric odd nitrogen concentrations of less than 0.1% as a result of this GLE.

scholarly journals Northern Hemisphere atmospheric influence of the solar proton events and ground level enhancement in January 2005

2011 ◽  
Vol 11 (13) ◽  
pp. 6153-6166 ◽  
Author(s):  
C. H. Jackman ◽  
D. R. Marsh ◽  
F. M. Vitt ◽  
R. G. Roble ◽  
C. E. Randall ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Atmospheric Chemistry ◽  
Climate Model ◽  
Michelson Interferometer ◽  
Ground Level ◽  
Solar Proton ◽  
Ground Level Enhancement ◽  
Time Period ◽  
Nitrogen Concentrations ◽  
Solar Proton Events

Abstract. Solar eruptions in early 2005 led to a substantial barrage of charged particles on the Earth's atmosphere during the 16–21 January period. Proton fluxes were greatly increased during these several days and led to the production of HOx (H, OH, HO2) and NOx (N, NO, NO2), which then caused the destruction of ozone. We focus on the Northern polar region, where satellite measurements and simulations with the Whole Atmosphere Community Climate Model (WACCM3) showed large enhancements in mesospheric HOx and NOx constituents, and associated ozone reductions, due to these solar proton events (SPEs). The WACCM3 simulations show enhanced short-lived OH and HO2 concentrations throughout the mesosphere in the 60–82.5° N latitude band due to the SPEs for most days in the 16–21 January 2005 period, somewhat higher in abundance than those observed by the Aura Microwave Limb Sounder (MLS). These HOx enhancements led to huge predicted and MLS-measured ozone decreases of greater than 40 % throughout most of the northern polar mesosphere during the SPE period. Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) measurements of hydrogen peroxide (H2O2) show increases throughout the stratosphere with highest enhancements of about 60 pptv in the lowermost mesosphere over the 16–18 January 2005 period due to the solar protons. WACCM3 predictions indicate H2O2 enhancements over the same time period of about three times that amount. Measurements of nitric acid (HNO3) by both MLS and MIPAS show an increase of about 1 ppbv above background levels in the upper stratosphere during 16–29 January 2005. WACCM3 simulations show only minuscule HNO3 increases (<0.05 ppbv) in the upper stratosphere during this time period. Polar mesospheric enhancements of NOx are computed to be greater than 50 ppbv during the SPE period due to the small loss rates during winter. Computed NOx increases, which were statistically significant at the 95 % level, lasted about a month past the SPEs. The SCISAT-1 Atmospheric Chemistry Experiment Fourier Transform Spectrometer NOx measurements and MIPAS NO2 measurements for the polar Northern Hemisphere are in reasonable agreement with these predictions. An extremely large ground level enhancement (GLE) occurred during the SPE period on 20 January 2005. We find that protons of energies 300 to 20 000 MeV, associated with this GLE, led to very small enhanced lower stratospheric odd nitrogen concentrations of less than 0.1 % and ozone decreases of less than 0.01 %.

scholarly journals Ionization effect of solar particle GLE events in low and middle atmosphere

2010 ◽  
Vol 10 (12) ◽  
pp. 30381-30404 ◽  
Author(s):  
I. G. Usoskin ◽  
G. A. Kovaltsov ◽  
I. A. Mironova ◽  
A. J. Tylka ◽  
W. F. Dietrich
Keyword(s):  
Middle Atmosphere ◽  
Ground Level ◽  
Solar Proton ◽  
Energy Spectra ◽  
Wide Energy Range ◽  
Ground Level Enhancement ◽  
Direct Ionization ◽  
Ionization Effect ◽  
The World ◽  
Wide Energy

Abstract. Using a new reconstruction of the solar proton energy spectra for Ground Level Enhancement (GLE) events, based on fits to measurements from ground-based and satellite-borne instruments covering a wide energy range, we quantitatively evaluate the possible ionization effects in the low and middle atmosphere for 58 out of the 66 GLE events recorded by the world-wide neutron monitor network since 1956. The ionization computations are based on the numerical 3-D CRAC:CRII model. A table of the ionization effect caused by the GLE events at different atmospheric heights is provided. It is shown that the direct ionization effect is negligible or even negative, due to the accompanying Forbush decreases, in all low- and mid-latitude regions. The ionization effect is important only in the polar atmosphere, where it can be dramatic in the middle and upper atmosphere (above 30 km) during major GLE events.

THE GROUND-LEVEL ENHANCEMENT OF 2012 MAY 17: DERIVATION OF SOLAR PROTON EVENT PROPERTIES THROUGH THE APPLICATION OF THE NMBANGLE PPOLA MODEL

2014 ◽  
Vol 785 (2) ◽  
pp. 160 ◽  
Author(s):  
Christina Plainaki ◽  
Helen Mavromichalaki ◽  
Monica Laurenza ◽  
Maria Gerontidou ◽  
Anastasios Kanellakopoulos ◽  
...  
Keyword(s):  
Ground Level ◽  
Solar Proton ◽  
Solar Proton Event ◽  
Proton Event ◽  
Ground Level Enhancement

scholarly journals Ionization effect of solar particle GLE events in low and middle atmosphere

2011 ◽  
Vol 11 (5) ◽  
pp. 1979-1988 ◽  
Author(s):  
I. G. Usoskin ◽  
G. A. Kovaltsov ◽  
I. A. Mironova ◽  
A. J. Tylka ◽  
W. F. Dietrich
Keyword(s):  
Middle Atmosphere ◽  
Ground Level ◽  
Solar Proton ◽  
Energy Spectra ◽  
Wide Energy Range ◽  
Ground Level Enhancement ◽  
Direct Ionization ◽  
Ionization Effect ◽  
The World ◽  
Wide Energy

Abstract. Using a new reconstruction of the solar proton energy spectra for Ground Level Enhancement (GLE) events, based on fits to measurements from ground-based and satellite-borne instruments covering a wide energy range, we quantitatively evaluate the possible ionization effects in the low and middle atmosphere for 58 out of the 66 GLE events recorded by the world-wide neutron monitor network since 1956. The ionization computations are based on the numerical 3D CRAC:CRII model. A table of the ionization effect caused by the GLE events at different atmospheric heights is provided. It is shown that the direct ionization effect is negligible or even negative, due to the accompanying Forbush decreases, in all low- and mid-latitude regions. The ionization effect is important only in the polar atmosphere, where it can be dramatic in the middle and upper atmosphere (above 30 km) during major GLE events.

scholarly journals Radiation dose of aircrews during a solar proton event without ground-level enhancement

2015 ◽  
Vol 33 (1) ◽  
pp. 75-78 ◽  
Author(s):  
R. Kataoka ◽  
Y. Nakagawa ◽  
T. Sato
Keyword(s):  
Radiation Dose ◽  
Solar Energetic Particle ◽  
Ground Level ◽  
Solar Proton ◽  
Significant Enhancement ◽  
Radiation Hazard ◽  
Proton Event ◽  
Ground Level Enhancement ◽  
Air Shower ◽  
Open Question

Abstract. A significant enhancement of radiation doses is expected for aircrews during ground-level enhancement (GLE) events, while the possible radiation hazard remains an open question during non-GLE solar energetic particle (SEP) events. Using a new air-shower simulation driven by the proton flux data obtained from GOES satellites, we show the possibility of significant enhancement of the effective dose rate of up to 4.5 μSv h−1 at a conventional flight altitude of 12 km during the largest SEP event that did not cause a GLE. As a result, a new GOES-driven model is proposed to give an estimate of the contribution from the isotropic component of the radiation dose in the stratosphere during non-GLE SEP events.

Onsets of Solar Proton Events in Satellite and Ground Level Observations: A Comparison

Space Weather ◽  
2018 ◽  
Vol 16 (3) ◽  
pp. 245-260 ◽  
Author(s):  
Jing He ◽  
Juan V. Rodriguez
Keyword(s):  
Ground Level ◽  
Solar Proton ◽  
Solar Proton Events

scholarly journals Statistical analysis of solar proton events

2004 ◽  
Vol 22 (6) ◽  
pp. 2255-2271 ◽  
Author(s):  
V. Kurt ◽  
A. Belov ◽  
H. Mavromichalaki ◽  
M. Gerontidou
Keyword(s):  
Statistical Analysis ◽  
Weather Prediction ◽  
Ground Level ◽  
Solar Proton ◽  
Longitudinal Distribution ◽  
Solar Cycles ◽  
Data Set ◽  
Time Period ◽  
Solar Proton Events

Abstract. A new catalogue of 253 solar proton events (SPEs) with energy >10MeV and peak intensity >10 protons/cm2.s.sr (pfu) at the Earth's orbit for three complete 11-year solar cycles (1970-2002) is given. A statistical analysis of this data set of SPEs and their associated flares that occurred during this time period is presented. It is outlined that 231 of these proton events are flare related and only 22 of them are not associated with Ha flares. It is also noteworthy that 42 of these events are registered as Ground Level Enhancements (GLEs) in neutron monitors. The longitudinal distribution of the associated flares shows that a great number of these events are connected with west flares. This analysis enables one to understand the long-term dependence of the SPEs and the related flare characteristics on the solar cycle which are useful for space weather prediction.

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