The effects of the big storm events in the first half of 2015 on the  radiation belts observed by EPT/PROBA-V

Pierrard, Viviane; Rosson, Graciela Lopez

doi:10.5194/angeo-34-75-2016

Cited by 24 publications

(32 citation statements)

References 32 publications

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“…The peak ozone anomaly occurs in August around 3 hPa, reaching ∼ 15 %. Our results agree with the results from previous modelling studies (Reddmann et al, 2010;Rozanov et al, 2012;Sinnhuber et al, 2018) and observations (Damiani et al, 2016;Fytterer et al, 2015).…”

Section: O 3 Anomaly Propagationsupporting

confidence: 93%

Reactive nitrogen (NOy) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

et al. 2019

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Abstract. Energetic particle precipitation (EPP) affects the chemistry of the polar middle atmosphere by producing reactive nitrogen (NOy) and hydrogen (HOx) species, which then catalytically destroy ozone. Recently, there have been major advances in constraining these particle impacts through a parametrization of NOy based on high-quality observations. Here we investigate the effects of low (auroral) and middle (radiation belt) energy range electrons, separately and in combination, on reactive nitrogen and hydrogen species as well as on ozone during Southern Hemisphere winters from 2002 to 2010 using the SOCOL3-MPIOM chemistry-climate model. Our results show that, in the absence of solar proton events, low-energy electrons produce the majority of NOy in the polar mesosphere and stratosphere. In the polar vortex, NOy subsides and affects ozone at lower altitudes, down to 10 hPa. Comparing a year with high electron precipitation with a quiescent period, we found large ozone depletion in the mesosphere; as the anomaly propagates downward, 15 % less ozone is found in the stratosphere during winter, which is confirmed by satellite observations. Only with both low- and middle-energy electrons does our model reproduce the observed stratospheric ozone anomaly.

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Section: O 3 Anomaly Propagationsupporting

confidence: 93%

Reactive nitrogen (NOy) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

et al. 2019

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“…While a further dedicated investigation should be undertaken, many of the shock-sheath structures discussed here have been studied recently for their strong effects on radiation belt electrons (for example, 1 and 8 October 2012 [Baker et al, 2013;Turner et al, 2014]; Hudson et al, 2014], 17 March 2013 [Boyd et al, 2014], 12 September 2014 [Alves et al, 2016], 17 March 2015 [Pierrard and Lopez Rosson, 2016;Li et al, 2016], and 22-25 June 2015 [Baker et al, 2016]). We have found that one of the conditions that makes shock-sheath structures geoeffective is a relatively steady southward B z upstream of the shock due to a preceding transient or preexisting southward IMF in the solar wind.…”

Section: Discussionmentioning

confidence: 99%

Factors affecting the geoeffectiveness of shocks and sheaths at 1 AU

et al. 2016

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We identify all fast‐mode forward shocks, whose sheath regions resulted in a moderate (56 cases) or intense (38 cases) geomagnetic storm during 18.5 years from January 1997 to June 2015. We study their main properties, interplanetary causes, and geoeffects. We find that half (49/94) such shocks are associated with interacting coronal mass ejections (CMEs), as they are either shocks propagating into a preceding CME (35 cases) or a shock propagating into the sheath region of a preceding shock (14 cases). About half (22/45) of the shocks driven by isolated transients and which have geoeffective sheaths compress preexisting southward Bz. Most of the remaining sheaths appear to have planar structures with southward magnetic fields, including some with planar structures consistent with field line draping ahead of the magnetic ejecta. A typical (median) geoeffective shock‐sheath structure drives a geomagnetic storm with peak Dst of −88 nT pushes the subsolar magnetopause location to 6.3 RE, i.e., below geosynchronous orbit and is associated with substorms with a peak AL index of −1350 nT. There are some important differences between sheaths associated with CME‐CME interaction (stronger storms) and those associated with isolated CMEs (stronger compression of the magnetosphere). We detail six case studies of different types of geoeffective shock‐sheaths, as well as two events for which there was no geomagnetic storm but other magnetospheric effects. Finally, we discuss our results in terms of space weather forecasting and potential effects on Earth's radiation belts.

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“…Such storms are characterized first by a dropout during the main phase, generally followed by a flux increase in the outer belt and injections in the slot region. Some injections even reach the inner belt during several storms, mainly during the more severe ones appearing in 2015 (Pierrard & Lopez Rosson, ) but also in 2016 and 2017.…”

Section: Time Variations In Ept Observationsmentioning

confidence: 99%

Dynamics of Megaelectron Volt Electrons Observed in the Inner Belt by PROBA‐V/EPT

2019

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Using the observations of the EPT (Energetic Particle Telescope) onboard the satellite PROBA-V, we study the dynamics of inner and outer belt electrons from 500 keV to 8 MeV during quiet periods and geomagnetic storms. This high time-resolution (2-s) spectrometer operating at the altitude of 820 km on a low polar orbit is providing continuously valuable electrons fluxes for already 5 years. We emphasize especially that some megaeleactron volt electrons are observed in low quantities in the inner belt, even during periods when they are not observed by Van Allen Probes. We show that they are not due to proton contamination but to clear injections of particles from the outer belt during strong geomagnetic storms of March and June 2015, and September 2017. Electrons with lower energy are injected also during less strong storms and the L shell of the electron flux peak in the outer belt shifts inward with a high dependence on the electron energy. With the new high-resolution EPT instrument, we can study the dynamics of relativistic electrons, including megaelectron volt electrons in the inner radiation belt, revealing how and when such electrons are injected into the inner belt and how long they reside there before being scattered into the Earth's atmosphere or lost by other mechanisms.Plain Language Summary New high resolution EPT/PROBA-V measurements of the electrons fluxes allow us to better understand the dynamics of the electrons in the inner and outer radiation belts. EPT put in perspective the VAP discovery that the expected population of MeV electrons in the inner belt was "missing" and that previous studies suggesting a long-lived, relatively static inner radiation belts likely misidentified penetrating protons as inner belt electrons. Some MeV electrons are observed by EPT in the inner belt, but in very low quantity. This observation of EPT cannot be due to proton contamination since injections associated to geomagnetic storms are clearly identified. The new capability of EPT to well discriminate the particle species and energy ranges led to new discoveries concerning their source and loss mechanisms regarding the dynamics in this region.

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The effects of the big storm events in the first half of 2015 on the radiation belts observed by EPT/PROBA-V

Cited by 24 publications

References 32 publications

Reactive nitrogen (NO<sub><i>y</i></sub>) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

Reactive nitrogen (NO<sub><i>y</i></sub>) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

Factors affecting the geoeffectiveness of shocks and sheaths at 1 AU

Dynamics of Megaelectron Volt Electrons Observed in the Inner Belt by PROBA‐V/EPT

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The effects of the big storm events in the first half of 2015 on the radiation belts observed by EPT/PROBA-V

Cited by 24 publications

References 32 publications

Reactive nitrogen (NO&lt;sub&gt;&lt;i&gt;y&lt;/i&gt;&lt;/sub&gt;) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

Reactive nitrogen (NO&lt;sub&gt;&lt;i&gt;y&lt;/i&gt;&lt;/sub&gt;) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

Factors affecting the geoeffectiveness of shocks and sheaths at 1 AU

Dynamics of Megaelectron Volt Electrons Observed in the Inner Belt by PROBA‐V/EPT

Contact Info

Product

Resources

About

Reactive nitrogen (NO<sub><i>y</i></sub>) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

Reactive nitrogen (NO<sub><i>y</i></sub>) and ozone responses to energetic electron precipitation during Southern Hemisphere winter