Energetic particle precipitation into the high-latitude ionosphere and the auroral electrojets: 3. Characteristics of electron precipitation into the morning sector auroral oval

1985 ◽  
Vol 90 (A8) ◽  
pp. 7495-7504 ◽  
Author(s):  
G. Rostoker ◽  
Y. Kamide ◽  
J. D. Winningham
Keyword(s):  
High Latitude ◽  
Energetic Particle ◽  
Auroral Oval ◽  
Electron Precipitation ◽  
Particle Precipitation ◽  
Morning Sector ◽  
High Latitude Ionosphere ◽  
Energetic Particle Precipitation

scholarly journals On the relationship of energetic particle precipitation and mesopause temperature

2021 ◽  
Vol 39 (5) ◽  
pp. 795-809
Author(s):  
Florine Enengl ◽  
Noora Partamies ◽  
Nickolay Ivchenko ◽  
Lisa Baddeley
Keyword(s):  
Temperature Change ◽  
Electron Density ◽  
Energetic Particle ◽  
Rotational Temperature ◽  
Electron Precipitation ◽  
Particle Precipitation ◽  
Vertical Temperature Profile ◽  
Mesopause Region ◽  
Energetic Particle Precipitation ◽  
Precipitation Events

Abstract. Energetic particle precipitation (EPP) has the potential to change the neutral atmospheric temperature in the mesopause region. However, recent results are inconsistent, leaving the mechanism and the actual effect still unresolved. In this study we have searched for electron precipitation events and investigated a possible correlation between D-region electron density enhancements and simultaneous neutral temperature changes. The rotational temperature of the excited hydroxyl (OH) molecules is retrieved from the infrared spectrum of the OH airglow. The electron density is monitored by the European Incoherent Scatter Scientific Association (EISCAT) Svalbard Radar. We use all available experiments from the International Polar Year (IPY) in 2007–2008 until February 2019. Particle precipitation events are characterized by rapid increases in electron density by a factor of 4 at an altitude range of 80–95 km, which overlaps with the nominal altitude of the infrared OH airglow layer. The OH airglow measurements and the electron density measurements are co-located. Six of the 10 analysed electron precipitation events are associated with a temperature decrease of 10–20 K. Four events were related to a temperature change of less than 10 K. We interpret the results in terms of the change in the chemical composition in the mesosphere. Due to EPP ionization the population of excited OH at the top of the airglow layer may decrease. As a consequence, the airglow peak height changes and the temperatures are probed at lower altitudes. The observed change in temperature thus depends on the behaviour of the vertical temperature profile within the airglow layer. This is in agreement with conclusions of earlier studies but is, for the first time, constructed from electron precipitation measurements as opposed to proxies. The EPP-related temperature change recovers very fast, typically within less than 60 min. We therefore further conclude that this type of EPP event reaching the mesopause region would only have a significant impact on the longer-term heat balance in the mesosphere if the lifetime of the precipitation was much longer than that of an EPP event (30–60 min) found in this study.

scholarly journals Exceptional middle latitude electron precipitation detected by balloon observations: implications for atmospheric composition

2021 ◽  
Author(s):  
Irina Mironova ◽  
Miriam Sinnhuber ◽  
Galina Bazilevskaya ◽  
Mark Clilverd ◽  
Bernd Funke ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Climate Model ◽  
High Energy ◽  
Energy Electron ◽  
Electron Precipitation ◽  
Atmospheric Composition ◽  
Precipitation Event ◽  
High Energy Electron ◽  
Particle Precipitation ◽  
Energetic Particle Precipitation

Abstract. Energetic particle precipitation leads to ionization in the Earth's atmosphere, initiating the formation of active chemical species which destroy ozone and have the potential to impact atmospheric composition and dynamics down to the troposphere. We report on one exceptionally strong high-energy electron precipitation event detected by balloon measurements in middle latitudes on 14 December 2009 with ionization rates locally comparable to strong solar proton events. This electron precipitation was likely caused by wave-particle interactions in the slot region between the inner and outer radiation belts, connected with still not well understood natural phenomena in the magnetosphere. Satellite observations of odd nitrogen and nitric acid are consistent with wide-spread electron precipitation into magnetic midlatitudes. Simulations with a 3D chemistry-climate model indicate almost complete destruction of ozone in the upper mesosphere over the region where high-energy electron precipitation occurred. Such an extraordinary type of energetic particle precipitation can have major implications for the atmosphere, and their frequency and strength should be carefully studied.

scholarly journals On the relationship of energetic particle precipitation and mesopause temperature

2020 ◽  
Author(s):  
Florine Enengl ◽  
Noora Partamies ◽  
Nickolay Ivchenko ◽  
Lisa Baddeley
Keyword(s):  
Temperature Change ◽  
Electron Density ◽  
Energetic Particle ◽  
Rotational Temperature ◽  
Atmospheric Temperature ◽  
Electron Precipitation ◽  
Particle Precipitation ◽  
International Polar Year ◽  
Energetic Particle Precipitation ◽  
Precipitation Events

Abstract. Energetic Particle Precipitation (EPP) has the potential to change the neutral atmospheric temperature at the mesopause region. Recent results, however, are inconsistent leaving the mechanism and the actual effect still unresolved. Here we have searched for electron precipitation events and investigated a possible correlation between D region electron density enhancements and simultaneous neutral temperature changes. The rotational temperature of the exited hydroxyl (OH) molecules is retrieved from the spectrum of the OH airglow. The electron density is monitored by the EISCAT Svalbard radar from the International Polar Year (IPY) in 2007–2008, when the EISCAT Svalbard radar was run continuously, until February 2019. Particle precipitation events are characterized by rapid increases in electron density by a factor of 4 at an altitude range of 80–95 km, which overlaps with the nominal altitude of the OH airglow layer. The OH airglow measurements and the electron density measurements are co-located. Most of our 8 electron precipitation events are associated with a temperature decrease of 10–50 K. Only one event was related to temperature change less than 10 K. We interpret the results in terms of the change in the chemical composition in the mesosphere. Due to EPP ionisation the population of excited OH at the top of the airglow layer decreases. As a consequence, the airglow peak height changes and the temperatures are probed at lower altitudes, providing inconsistent temperature responses. This is in agreement with conclusions of earlier studies, but is, for the first time, constructed from electron precipitation measurements as opposed proxies. The EPP related temperature change recovers very fast, typically within 30 minutes. We therefore further conclude that this type of particle precipitation events would only have a significant impact on the longer-term heat balance in the mesosphere if the lifetime of the precipitation was much longer than that of a typical EPP event found in this study.

scholarly journals A Statistical study of the Doppler spectral width of high-latitude ionospheric F-region echoes recorded with SuperDARN coherent HF radars

2002 ◽  
Vol 20 (11) ◽  
pp. 1769-1781 ◽  
Author(s):  
J.-P. Villain ◽  
R. André ◽  
M. Pinnock ◽  
R. A. Greenwald ◽  
C. Hanuise
Keyword(s):  
High Latitude ◽  
Statistical Study ◽  
Spectral Width ◽  
Auroral Oval ◽  
F Region ◽  
Radar Network ◽  
Period 2 ◽  
Time Period ◽  
High Latitude Ionosphere ◽  
Data Points

Abstract. The HF radars of the Super Dual Auroral Radar Network (SuperDARN) provide measurements of the E × B drift of ionospheric plasma over extended regions of the high-latitude ionosphere. We have conducted a statistical study of the associated Doppler spectral width of ionospheric F-region echoes. The study has been conducted with all available radars from the Northern Hemisphere for 2 specific periods of time. Period 1 corresponds to the winter months of 1994, while period 2 covers October 1996 to March 1997. The distributions of data points and average spectral width are presented as a function of Magnetic Latitude and Magnetic Local Time. The databases are very consistent and exhibit the same features. The most stringent features are: a region of very high spectral width, collocated with the ionospheric LLBL/cusp/mantle region; an oval shaped region of high spectral width, whose equator-ward boundary matches the poleward limit of the Holzworth and Meng auroral oval. A simulation has been conducted to evaluate the geometrical and instrumental effects on the spectral width. It shows that these effects cannot account for the observed spectral features. It is then concluded that these specific spectral width characteristics are the signature of ionospheric/magnetospheric coupling phenomena.Key words. Ionosphere (auroral ionosphere; ionosphere-magnetosphere interactions; ionospheric irregularities)

scholarly journals Impact of energetic particle precipitation on stratospheric polar constituents: an assessment using MIPAS data monitoring and assimilation

2009 ◽  
Vol 9 (5) ◽  
pp. 22459-22504
Author(s):  
A. Robichaud ◽  
R. Ménard ◽  
S. Chabrillat ◽  
J. de Grandpré ◽  
Y. J. Rochon ◽  
...  
Keyword(s):  
Gas Phase ◽  
Energetic Particle ◽  
Solar Proton ◽  
Significant Loss ◽  
Proton Event ◽  
Particle Precipitation ◽  
Gas Phase Chemistry ◽  
Energetic Particle Precipitation ◽  
Phase Chemistry ◽  
Assimilation System

Abstract. In 2003, strong geomagnetic events occurred which produced massive amounts of energetic particles penetrating the top of the atmospheric polar region, significantly perturbing its chemical state down to the middle stratosphere. These events and their effects are generally left unaccounted for in current models of stratospheric chemistry and large differences between observations and models are then noted. In this study, we use a coupled 3-D stratospheric dynamical-chemical model and assimilation system to ingest MIPAS temperature and chemical observations. The goal is to gain further understanding and to evaluate the impacts of EPP (energetic particle precipitation) on stratospheric polar chemistry. Moreover, we investigate the feasibility of assimilating valid "outlier" observations associated with such events. We focus our analysis on OmF (Observation minus Forecast) residuals as they filter out phenomena well reproduced by the model (such as gas phase chemistry, transport, diurnal and seasonal cycles) thus revealing a clear trace of the EPP. Inspection of OmF statistics in both the passive (without chemical assimilation) and active (with chemical assimilation) cases altogether provides a powerful diagnostic tool to assess the model and assimilation system. We also show that passive OmF can permit a satisfactory evaluation of the ozone partial column loss due to EPP effects. Results suggest a small but significant loss of 5–6 DU (Dobson Units) during an EPP-IE (EPP indirect effects) event in the Antarctic winter of 2003, and about only 1 DU for the SPE (solar proton event) of October/November 2003. Despite large differences between the model and MIPAS chemical observations (NO2, HNO3, CH4 and O3), we demonstrate that a careful assimilation of these constituents with only gas phase chemistry included in the model (i.e. no provision for EPP impacts) and with relaxed quality control nearly eliminated the short-term bias and significantly reduced the standard deviation error below 1 hPa.

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