Characteristics of solar proton events associated with ground level enhancements

The global neutron monitor network has been successfully used over several decades to study cosmic ray variations and fluxes of energetic solar particles. Nowadays, it is used also for space weather purposes, e.g. alerts and assessment of the exposure to radiation. Here, we present the current status of the global neutron monitor network. We discuss the ability of the global neutron monitor network to study solar energetic particles, specifically during large ground level enhancements. We demonstrate as an example, the derived solar proton characteristics during ground level enhancements GLE #5 and the resulting effective dose over the globe at a typical commercial jet flight altitude of 40 kft (≈12,200 m) above sea level. We present a plan for improvement of space weather services and applications of the global neutron monitor network, specifically for studies related to solar energetic particles, namely an extension of the existing network with several new monitors. We discuss the ability of the optimized global neutron monitor network to study various populations of solar energetic particles and to provide reliable space weather services.

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

Space Weather ◽

10.1002/2017sw001743 ◽

2018 ◽

Vol 16 (3) ◽

pp. 245-260 ◽

Cited By ~ 4

Author(s):

Jing He ◽

Juan V. Rodriguez

Keyword(s):

Ground Level ◽

Solar Proton ◽

Solar Proton Events

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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-7715-2011 ◽

2011 ◽

Vol 11 (3) ◽

pp. 7715-7755 ◽

Cited By ~ 1

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.

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Statistical analysis of solar proton events

Annales Geophysicae ◽

10.5194/angeo-22-2255-2004 ◽

2004 ◽

Vol 22 (6) ◽

pp. 2255-2271 ◽

Cited By ~ 38

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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The Cosmic Ray Solar Flare Increase of 16 February 1984

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000017690 ◽

1984 ◽

Vol 5 (4) ◽

pp. 593-594

Author(s):

A. G. Fenton ◽

K. B. Fenton ◽

J. E. Humble

Keyword(s):

Solar Activity ◽

Solar Cycle ◽

Solar Flare ◽

Cosmic Ray ◽

Ground Level ◽

Solar Proton ◽

Solar Proton Events

Six solar proton events have been observed by ground level cosmic ray detectors so far during solar cycle 21, a little less than one per year. All of these have been much smaller than the giant events observed in solar cycle 19. As with many other aspects of solar activity, the reason for the differences from cycle to cycle remain unknown.

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