Energetic electron precipitation into the middle atmosphere—Constructing the loss cone fluxes from MEPED POES

Tyssøy, Hilde Nesse; Sandanger, Marit Irene; Ødegaard, L. K. Glesnes; Stadsnes, J.; Aasnes, A.; Zawedde, Annet Eva

doi:10.1002/2016ja022752

Cited by 63 publications

(141 citation statements)

References 47 publications

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“…However, precise measurements of the electron precipitation characteristics are not easy to make [e.g., Rodger et al , ; Nesse Tyssøy et al ., ; Crew et al , ]. There are three main techniques that are used: satellite detectors, high‐altitude balloon‐lofted platforms, and ground‐based instrumentation.…”

Section: Introductionmentioning

confidence: 99%

Investigating energetic electron precipitation through combining ground‐based and balloon observations

et al. 2017

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A detailed comparison is undertaken of the energetic electron spectra and fluxes of two precipitation events that were observed in 18/19 January 2013. A novel but powerful technique of combining simultaneous ground‐based subionospheric radio wave data and riometer absorption measurements with X‐ray fluxes from a Balloon Array for Relativistic Radiation‐belt Electron Losses (BARREL) balloon is used for the first time as an example of the analysis procedure. The two precipitation events are observed by all three instruments, and the relative timing is used to provide information/insight into the spatial extent and evolution of the precipitation regions. The two regions were found to be moving westward with drift periods of 5–11 h and with longitudinal dimensions of ~20° and ~70° (1.5–3.5 h of magnetic local time). The electron precipitation spectra during the events can be best represented by a peaked energy spectrum, with the peak in flux occurring at ~1–1.2 MeV. This suggests that the radiation belt loss mechanism occurring is an energy‐selective process, rather than one that precipitates the ambient trapped population. The motion, size, and energy spectra of the patches are consistent with electromagnetic ion cyclotron‐induced electron precipitation driven by injected 10–100 keV protons. Radio wave modeling calculations applying the balloon‐based fluxes were used for the first time and successfully reproduced the ground‐based subionospheric radio wave and riometer observations, thus finding strong agreement between the observations and the BARREL measurements.

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Section: Introductionmentioning

confidence: 99%

Investigating energetic electron precipitation through combining ground‐based and balloon observations

et al. 2017

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“…The two MEPED electron solid‐state detectors monitor the intensity of electrons in three nominal energy bands: >30, >100, and >300 keV (Evans & Greer, ), whose known data challenges have been catered for using the new analysis toolbox described by Nesse Tyssøy et al (). In this toolbox, the proton fluxes are corrected for degradation due to radiation damage by applying correction factors derived by Sandanger et al () and Ødegaard et al ().…”

Section: Datamentioning

confidence: 99%

“…Since the geometric factor for the electron detectors varies with energy, Ødegaard et al () calculated new optimized geometric factors and the associated new energy thresholds for the electron channels are >43, >114, >292, and >757 keV. The fourth electron channel is derived from relativistic electron contamination of the p6 channel of the proton telescope detectors as described by Nesse Tyssøy et al ().…”

Section: Datamentioning

confidence: 99%

“…If there is strong pitch angle diffusion and an isotropic distribution of the particles, the 0° and 90° telescopes give a realistic estimate of the precipitating particle fluxes. Otherwise the 0° and 90° telescopes will either underestimate or overestimate the flux of the precipitating particles, respectively, with decreasing fluxes toward the center of the loss cone (Nesse Tyssøy et al, ; Rodger et al, , ). Therefore, a complete bounce loss cone flux is constructed for each of the new electron energy channels (Ødegaard et al, ), using measurements from both the 0° and 90° telescopes in conjunction with electron pitch angle distribution theory as described by Nesse Tyssøy et al ().…”

Section: Datamentioning

confidence: 99%

“…By applying a new analysis technique on measurements from the Medium Energy Proton and Electron Detector (MEPED) on the National Oceanic and Atmospheric Administration (NOAA) Polar Orbiting Environmental Satellites (POES), an estimate of the flux of precipitating electrons is obtained by measurements from both the 0° and 90° telescopes (Nesse Tyssøy et al, ; Ødegaard et al, ). An estimate of the flux of precipitating protons is obtained by combining measurements from the MEPED 0° telescope and the omnidirectional detectors (0–60°) (Nesse Tyssøy et al, ; Nesse Tyssøy & Stadsnes, ).…”

Section: Introductionmentioning

confidence: 99%

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The Impact of Energetic Particle Precipitation on Mesospheric OH – Variability of the Sources and the Background Atmosphere

et al. 2018

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Using a new analysis technique, we estimate the precipitating particle fluxes measured by the Medium Energy Proton and Electron Detector on the National Oceanic and Atmospheric Administration Polar Orbiting Environmental Satellites. These fluxes are used to quantify the direct impact of energetic particle precipitation (EPP) on mesospheric hydroxyl (OH) measured from the Aura satellite during 2005–2009 in the Northern Hemisphere, covering the declining and minimum phase of solar cycle 23. Using multiple linear regression of nighttime OH volume mixing ratio with temperature, geopotential height, water vapor (H2O) volume mixing ratio, Lyman‐alpha (Ly‐α) radiation, and particle energy deposition, we account for the background variability and hence the EPP impact independent of season and other short‐term variability. We investigate the relative importance of solar proton events, energetic electron precipitation and the background to OH variability. The background dominates over EPP above 70‐km altitude. Below 70 km, EPP dominates. The maximum EPP contribution is 44% and 34% in the geographic and corrected geomagnetic (CGM) settings respectively at 67 km. Protons dominate over electrons at mesospheric altitudes with maximum contributions of 43% and 32% at 67 km in the geographic and CGM settings, respectively. In a CGM setting, the electrons contribution is comparable to that of protons above 70 km, with a maximum contribution of 11% at 75 km. Since the period investigated is during relatively low solar activity, these results represent a lower estimate of the general EPP contribution to OH variability.

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A model providing long‐term data sets of energetic electron precipitation during geomagnetic storms

et al. 2016

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The influence of solar variability on the polar atmosphere and climate due to energetic electron precipitation (EEP) has remained an open question largely due to lack of a long-term EEP forcing data set that could be used in chemistry-climate models. Motivated by this, we have developed a model for 30-1000 keV radiation belt driven EEP. The model is based on precipitation data from low Earth orbiting POES satellites in the period 2002-2012 and empirically described plasmasphere structure, which are both scaled to a geomagnetic index. This geomagnetic index is the only input of the model and can be either Dst or Ap. Because of this, the model can be used to calculate the energy-flux spectrum of precipitating electrons from 1957 (Dst) or 1932 (Ap) onward, with a time resolution of 1 day. Results from the model compare well with EEP observations over the period of 2002-2012. Using the model avoids the challenges found in measured data sets concerning proton contamination. As demonstrated, the model results can be used to produce the first ever >80 year long atmospheric ionization rate data set for radiation belt EEP. The impact of precipitation in this energy range is mainly seen at altitudes 70-110 km. The ionization rate data set, which is available for the scientific community, will enable simulations of EEP impacts on the atmosphere and climate with realistic EEP variability. Due to limitations in this first version of the model, the results most likely represent an underestimation of the total EEP effect.

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Energetic electron precipitation into the middle atmosphere—Constructing the loss cone fluxes from MEPED POES

Cited by 63 publications

References 47 publications

Investigating energetic electron precipitation through combining ground‐based and balloon observations

Investigating energetic electron precipitation through combining ground‐based and balloon observations

The Impact of Energetic Particle Precipitation on Mesospheric OH – Variability of the Sources and the Background Atmosphere

A model providing long‐term data sets of energetic electron precipitation during geomagnetic storms

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