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 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 Pre-Seismic Irregularities during the 2020 Samos (Greece) Earthquake (M = 6.9) as Investigated from Multi-Parameter Approach by Ground and Space-Based Techniques

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1059
Author(s):  
Sudipta Sasmal ◽  
Swati Chowdhury ◽  
Subrata Kundu ◽  
Dimitrios Z. Politis ◽  
Stelios M. Potirakis ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Potential Energy ◽  
Electron Density ◽  
Energetic Particle ◽  
Radiation Belt ◽  
Significant Enhancement ◽  
Electron Content ◽  
Particle Precipitation ◽  
Total Electron ◽  
Energetic Particle Precipitation

We present a comprehensive analysis of pre-seismic anomalies as computed from the ground and space-based techniques during the recent Samos earthquake in Greece on 30 October 2020, with a magnitude M = 6.9. We proceed with a multi-parametric approach where pre-seismic irregularities are investigated in the stratosphere, ionosphere, and magnetosphere. We use the convenient methods of acoustics and electromagnetic channels of the Lithosphere–Atmosphere–Ionosphere-Coupling (LAIC) mechanism by investigating the Atmospheric Gravity Wave (AGW), magnetic field, electron density, Total Electron Content (TEC), and the energetic particle precipitation in the inner radiation belt. We incorporate two ground-based IGS GPS stations DYNG (Greece) and IZMI (Turkey) for computing the TEC and observed a significant enhancement in daily TEC variation around one week before the earthquake. For the space-based observation, we use multiple parameters as recorded from Low Earth Orbit (LEO) satellites. For the AGW, we use the SABER/TIMED satellite data and compute the potential energy of stratospheric AGW by using the atmospheric temperature profile. It is found that the maximum potential energy of such AGW is observed around six days before the earthquake. Similar AGW is also observed by the method of wavelet analysis in the fluctuation in TEC values. We observe significant energetic particle precipitation in the inner radiation belt over the earthquake epicenter due to the conventional concept of an ionospheric-magnetospheric coupling mechanism by using an NOAA satellite. We first eliminate the particle count rate (CR) due to possible geomagnetic storms and South Atlantic Anomaly (SAA) by the proper choice of magnetic field B values. After the removal of the statistical background CRs, we observe a significant enhancement of CR four and ten days before the mainshock. We use Swarm satellite outcomes to check the magnetic field and electron density profile over a region of earthquake preparation. We observe a significant enhancement in electron density one day before the earthquake. The parameters studied here show an overall pre-seismic anomaly from a duration of ten days to one day before the earthquake.

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 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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