scholarly journals The Predictive Capabilities of the Auroral Electrojet Index for Medium Energy Electron Precipitation

2021 ◽  
Vol 8 ◽  
Author(s):  
H. Nesse Tyssøy ◽  
N. Partamies ◽  
E. M. Babu ◽  
C. Smith-Johnsen ◽  
J. A. Salice
Keyword(s):  
Decadal Variability ◽  
Particle Interaction ◽  
Energetic Electron ◽  
High Energy ◽  
Energy Electron ◽  
Electron Precipitation ◽  
Medium Energy ◽  
Ae Index ◽  
High Energy Tail ◽  
Potential Link

The chemical imprint of the energetic electron precipitation on the atmosphere is now acknowledged as a part of the natural forcing of the climate system. It has, however, been questioned to which degree current proxies are able to quantify the medium energy electron (MEE) (≳30 keV) precipitation and the associated daily and decadal variability. It is particularly challenging to model the high energy tail (≳300 keV) of MEE, both in terms of the intensity as well as the timing. This study explores the predictive capabilities of the AE index for the MEE precipitation. MEE measurements from the NOAA/POES over a full solar cycle from 2004 to 2014 are applied. We combine observations from the MEPED 0° and 90° detectors together with theory of pitch angle diffusion by wave-particle interaction to estimate the precipitating fluxes. To explore the energy dependent time scales, each of the MEPED energy channels, > 43, >114, and >292 keV are evaluated independently. While there is a strong correlation between the daily resolved AE index and >43 keV fluxes, it is a poor predictor for the >292 keV fluxes. We create new AE based MEE proxies by accumulating the AE activity over multiple days, including terms counting for the associated lifetimes. The results indicate that AE based proxies can predict at least 70% of the observed MEE precipitation variance at all energies. The potential link between the AE index, substorms and the MEE precipitation is discussed.

scholarly journals Simulated seasonal impact on middle atmospheric ozone from high-energy electron precipitation related to pulsating aurorae

2021 ◽  
Vol 39 (5) ◽  
pp. 883-897
Author(s):  
Pekka T. Verronen ◽  
Antti Kero ◽  
Noora Partamies ◽  
Monika E. Szeląg ◽  
Shin-Ichiro Oyama ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Energetic Electron ◽  
Solar Energetic Particle ◽  
High Energy ◽  
Energy Electron ◽  
Electron Precipitation ◽  
Research Station ◽  
High Energy Electron

Abstract. Recent simulation studies have provided evidence that a pulsating aurora (PsA) associated with high-energy electron precipitation is having a clear local impact on ozone chemistry in the polar middle mesosphere. However, it is not clear if the PsA is frequent enough to cause longer-term effects of measurable magnitude. There is also an open question of the relative contribution of PsA-related energetic electron precipitation (PsA EEP) to the total atmospheric forcing by solar energetic particle precipitation (EPP). Here we investigate the PsA-EEP impact on stratospheric and mesospheric odd hydrogen, odd nitrogen, and ozone concentrations. We make use of the Whole Atmosphere Community Climate Model and recent understanding on PsA frequency, latitudinal and magnetic local time extent, and energy-flux spectra. Analysing an 18-month time period covering all seasons, we particularly look at PsA-EEP impacts at two polar observation stations located at opposite hemispheres: Tromsø in the Northern Hemisphere (NH) and Halley Research Station in the Southern Hemisphere (SH). We find that PsA EEP can have a measurable impact on ozone concentration above 30 km altitude, with ozone depletion by up to 8 % seen in winter periods due to PsA-EEP-driven NOx enhancement. We also find that direct mesospheric NOx production by high-energy electrons (E> 100 keV) accounts for about half of the PsA-EEP-driven upper stratospheric ozone depletion. A larger PsA-EEP impact is seen in the SH where the background dynamical variability is weaker than in the NH. Clearly indicated from our results, consideration of polar vortex dynamics is required to understand PsA-EEP impacts seen at ground observation stations, especially in the NH. We conclude that PsA-EEP has the potential to make an important contribution to the total EPP forcing; thus, it should be considered in atmospheric and climate simulations.

scholarly journals Strong localized variations of the low-altitude energetic electron fluxes in the evening sector near the plasmapause

1998 ◽  
Vol 16 (1) ◽  
pp. 25-33 ◽  
Author(s):  
E. E. Titova ◽  
T. A. Yahnina ◽  
A. G. Yahnin ◽  
B. B. Gvozdevsky ◽  
A. A. Lyubchich ◽  
...  
Keyword(s):  
Sharp Increase ◽  
Electron Flux ◽  
Particle Interaction ◽  
Energetic Electron ◽  
Recovery Phase ◽  
Electron Precipitation ◽  
Statistical Characteristics ◽  
Evening Sector ◽  
Proton Precipitation ◽  
Low Altitude

Abstract. Specific type of energetic electron precipitation accompanied by a sharp increase in trapped energetic electron flux are found in the data obtained from low-altitude NOAA satellites. These strongly localized variations of the trapped and precipitated energetic electron flux have been observed in the evening sector near the plasmapause during recovery phase of magnetic storms. Statistical characteristics of these structures as well as the results of comparison with proton precipitation are described. We demonstrate the spatial coincidence of localized electron precipitation with cold plasma gradient and whistler wave intensification measured on board the DE-1 and Aureol-3 satellites. A simultaneous localized sharp increase in both trapped and precipitating electron flux could be a result of significant pitch-angle isotropization of drifting electrons due to their interaction via cyclotron instability with the region of sharp increase in background plasma density.Key words. Ionosphere (particle precipitation; wave-particle interaction) Magnetospheric Physics (plasmasphere)

scholarly journals Pc5 modulation of high energy electron precipitation: particle interaction regions and scattering efficiency

2005 ◽  
Vol 23 (5) ◽  
pp. 1533-1542 ◽  
Author(s):  
E. Spanswick ◽  
E. Donovan ◽  
G. Baker
Keyword(s):  
Field Line ◽  
Electron Flux ◽  
High Energy ◽  
Energy Electron ◽  
Electron Precipitation ◽  
Necessary Condition ◽  
High Energy Electron ◽  
Magnetic Pulsation ◽  
Field Line Resonances ◽  
Morning Sector

Abstract. Using the NORSTAR riometer and CANOPUS magnetometer arrays we have investigated the modulation of high energy electron precipitation by ULF waves in the Pc5 frequency band. We conducted two separate studies of Pc5 activity in the riometers. The first is an independent survey of three riometer stations in the Churchill line (one at each sub-auroral, auroral, and typical polar cap boundary latitudes) in which we identified all riometer Pc5-band pulsations over 11 years. All had a corresponding magnetometer pulsation implying that a magnetic pulsation, is a necessary condition for a riometer pulsation (in the Pc5 Band). We find seasonal and latitude dependencies in the occurrence of riometer pulsations. By a factor of two, there are more riometer pulsations occurring in the fall-winter than the spring-summer. At higher latitudes there is a tendency towards noon pulsations during the spring-summer, suggesting that the criteria for riometer pulsations is affected by the dipole tilt. Our second study was based on the previous magnetometer study of Baker et al. (2003). Using the database of Pc5 activity from that study we were able to select the riometer Pc5 pulsations which adhere to the strict Pc5 definition in the magnetometer. We find that roughly 95% of the riometer pulsations occurred in the morning sector compared to 70% in the magnetometer. Given a magnetometer pulsation at Gillam in the morning sector, there is a 70% chance of there being a corresponding riometer pulsation. The morning sector probabilities at Rankin (geomagnetic (PACE) latitude 74°) and Pinawa (61°) are 3% and 5%, respectively. These statistics suggest there is a localized region in the pre-noon magnetosphere where Pc5 band ULF activity can modulate high energy electron precipitation. We also find that riometer pulsations display a Kp selection towards mid (i.e. 3–4) activity levels which mimics the product of the Kp dependence of high-energy electron fluxes on the dawn side (from CRRES) and all magnetic Pc5 activity. A superposed epoch analysis revealed that the elevated electron flux needed to produce a riometer pulsation is most likely provided by substorm injections on the nightside. We also find that the amplitude of modulated precipitation correlates well with the product of the background absorption and the magnetic pulsation amplitude, again leading to the idea that a riometer pulsation needs both favorable magnetospheric electron flux conditions and large enough magnetic Pc5 wave activity. We further separate our pulsations into field line resonances (FLRs), and non-field line resonances (non-FLRs), as identified in the Baker et al. (2003) survey. We find that FLRs are more efficient at modulating particle precipitation, and non-FLRs display an amplitude cutoff below which they do not interact with the high energy electron population. We conclude that the high energy electron precipitation associated with Pc5 pulsations is caused by pitch angle scattering (diffusion) rather than parallel acceleration. We suggest two future studies that are natural extensions of this one. Keywords. Energetic Particles/Precipitating; Wave-Particle Interactions; Auroral Phenomena

Mesospheric ozone destruction by high-energy electron precipitation associated with pulsating aurora

2016 ◽  
Vol 121 (19) ◽  
pp. 11,852-11,861 ◽  
Author(s):  
Esa Turunen ◽  
Antti Kero ◽  
Pekka T. Verronen ◽  
Yoshizumi Miyoshi ◽  
Shin-Ichiro Oyama ◽  
...  
Keyword(s):  
High Energy ◽  
Energy Electron ◽  
Electron Precipitation ◽  
High Energy Electron ◽  
Ozone Destruction ◽  
Mesospheric Ozone

Mesospheric ionization rates due to Medium Energy Electron Precipitation – an overview

2020 ◽  
Author(s):  
Hilde Nesse Tyssøy ◽  
Miriam Sinnhuber ◽  
Timo Asikainen ◽  
Max van de Kamp ◽  
Joshua Pettit ◽  
...  
Keyword(s):  
Full Range ◽  
Energetic Electron ◽  
Coupled Model ◽  
Space Physics ◽  
Energy Electron ◽  
Medium Energy ◽  
Loss Cone ◽  
Wide Range ◽  
The University ◽  
Ionization Rates

<p>Quantifying the ionization rates due to medium energy electron (MEE) precipitation into the mesosphere has long been an outstanding question. It is the key to understand the total effect of particle precipitation on the atmosphere. The first MEE ionization rate was provided by the Atmospheric Ionization Module Osnabrück (AIMOS) in 2009. It applies electron measurements by the 0<sup>o</sup> electron detector on the MEPED instrument on board the NOAA/POES satellites together with geomagnetic indices. Since then several other efforts to estimate the MEE precipitation and associated ionization rates has been made taking account e.g. of cross contamination by low-energy protons; Full Range Energy Electron Spectra (FRES) and ISSI-19. Recently, a parameterization based on the same electron data, scaled by the geomagnetic index Ap, has been included in the solar-driven particle forcing in the recommendation for Coupled Model Intercomparison Project 6 (CMIP6). Another parameterization aiming to resolve substorm activity applies the SML index, AISstorm. Further, three different methods to construct the total bounce loss cone fluxes based on both MEPED detectors has been suggested by the University of Colorado, University of Oulo, and the University of Bergen. In total, the space physics community offers a wide range of mesospheric ionization rates to be used in studies of the subsequent chemical-dynamical impact of the atmosphere, which are all based on the MEPED electron measurement.</p><p>Here we present a review of eight different estimates of energetic electron fluxes and the ionization rates during an event in April 2010. The objective of this comparison is to understand the potential uncertainty related to the MEE energy input in order to assess its subsequent impact on the atmosphere. We find that although the different parameterizations agree well in terms of the temporal variability, they differ by orders of magnitude in ionization strength both during geomagnetic quiet and disturbed periods and show some inconsistency in terms of latitudinal coverage.</p>

Effects of the 11-year Solar Cycle including Medium-Energy Electron Precipitation in WACCM decadal climate predictions

2020 ◽  
Author(s):  
Sigmund Guttu ◽  
Yvan Orsolini ◽  
Frode Stordal ◽  
Odd Helge Otterå ◽  
Thomas Toniazzo ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Solar Maximum ◽  
Energetic Electron ◽  
Atmospheric Model ◽  
High Energy ◽  
Ocean Model ◽  
Electron Precipitation ◽  
Atmospheric Variability ◽  
Data Set ◽  
The North

<p> There is an ongoing discussion whether the lagged surface impact of the 11-year solar cycle, which peaks 2-4 years after solar maximum, may be contributed by the North Atlantic Oscillation (NAO) coupling to the ocean. Several studies have suggested that this atmosphere-ocean feedback is involving annual re-emergence of anomalous ocean temperatures stored below the mixed layer. Energetic Electron precipitation effects also lag the solar maximum by a few years, peaking in the declining phase of the solar cycle. While recent studies have incorporated the stratospheric UV radiation component of the solar forcing, the importance of the effect from precipitating medium-to-high energy electrons (MEE), which are able to significantly disturb the stratospheric chemical composition, is not fully addressed, partly due to lack of realistic forcing in current Earth System Models. In this study, we use the high-top atmospheric model WACCM coupled to the MICOM ocean model and adopt a state-of-the-art MEE forcing data set. Results will be presented from two decadal ensemble experiments with solar cycle induced forcings, one with UV and one with UV and MEE. The anomalous forcing from MEE precipitation is studied in relation to patterns of Northern Hemispheric atmospheric variability modes.</p>

scholarly journals Longitudinal hotspots in the mesospheric OH variations due to energetic electron precipitation

2014 ◽  
Vol 14 (2) ◽  
pp. 1095-1105 ◽  
Author(s):  
M. E. Andersson ◽  
P. T. Verronen ◽  
C. J. Rodger ◽  
M. A. Clilverd ◽  
S. Wang
Keyword(s):  
Geomagnetic Activity ◽  
Function Analysis ◽  
Energetic Electron ◽  
High Energy ◽  
Electron Precipitation ◽  
Data Sets ◽  
Activity Levels ◽  
Atmospheric Conditions ◽  
Longitudinal Response ◽  
High Energy Electrons

Abstract. Using Microwave Limb Sounder (MLS/Aura) and Medium Energy Proton and Electron Detector (MEPED/POES) observations between 2005–2009, we study the longitudinal response of nighttime mesospheric OH to radiation belt electron precipitation. Our analysis concentrates on geomagnetic latitudes from 55–72° N/S and altitudes between 70 and 78 km. The aim of this study is to better assess the spatial distribution of electron forcing, which is important for more accurate modelling of its atmospheric and climate effects. In the Southern Hemisphere, OH data show a hotspot, i.e. area of higher values, at longitudes between 150° W–30° E, i.e. poleward of the Southern Atlantic Magnetic Anomaly (SAMA) region. In the Northern Hemisphere, energetic electron precipitation-induced OH variations are more equally distributed with longitude. This longitudinal behaviour of OH can also be identified using Empirical Orthogonal Function analysis, and is found to be similar to that of MEPED-measured electron fluxes. The main difference is in the SAMA region, where MEPED appears to measure very large electron fluxes while MLS observations show no enhancement of OH. This indicates that in the SAMA region the MEPED observations are not related to precipitating electrons, at least not at energies >100 keV, but rather to instrument contamination. Analysis of selected OH data sets for periods of different geomagnetic activity levels shows that the longitudinal OH hotspot south of the SAMA (the Antarctic Peninsula region) is partly caused by strong, regional electron forcing, although atmospheric conditions also seem to play a role. Also, a weak signature of this OH hotspot is seen during periods of generally low geomagnetic activity, which suggests that there is a steady drizzle of high-energy electrons affecting the atmosphere, due to the Earth's magnetic field being weaker in this region.

scholarly journals Pi2-pulsations observed in energetic electron precipitation and magnetic field in association with a substorm surge

2004 ◽  
Vol 22 (6) ◽  
pp. 2097-2105 ◽  
Author(s):  
A. Åsnes ◽  
J. Stadsnes ◽  
J. Bjordal ◽  
N. Østgaard ◽  
D. L. Detrick ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Particle Interaction ◽  
Energetic Electron ◽  
Global Scale ◽  
Electron Precipitation ◽  
High Temporal Resolution ◽  
Expansion Phase ◽  
Multiple Observations ◽  
Pi2 Pulsations ◽  
Polar Satellite

Abstract. For a substorm 24 July 1998 PIXIE observes the onset and expansion during a perigee pass of the Polar satellite. This gives an opportunity to follow the evolution of the onset and expansion phase, almost on a global scale with relatively high temporal resolution. The substorm is presented with multiple observations throughout the magnetosphere. Following the onset of the substorm we observe a localised region of modulated energetic electron fluxes following the passage of the westward travelling surge in the pre-midnight region. We count at least six clear pulses with a period of approximately one minute. Concurrent magnetic ground measurements show similar characteristics, almost simultaneously with the pulses in precipitation. We propose several possible mechanism for the pulsations, amongst them the theory of modulated wave particle interaction first proposed by coroniti70.

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