Browsing Bergen Open Research Archive by Author "Smith-Johnsen, Christine"
Now showing items 1-14 of 14
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Determining Latitudinal Extent of Energetic Electron Precipitation Using MEPED On-Board NOAA/POES
Babu, Eldho Midhun; Tyssøy, Hilde Nesse; Smith-Johnsen, Christine; Maliniemi, Ville Aleksi; Salice, Josephine Alessandra; Millan, R.M.; Richardson, I.G. (Journal article; Peer reviewed, 2022)Energetic Electron Precipitation (EEP) from the plasma sheet and the radiation belts ionizes the polar lower thermosphere and mesosphere. EEP increases the production of NOx and HOx, which will catalytically destroy ozone, ... -
Direct and indirect electron precipitation effect on nitric oxide in the polar middle atmosphere, using a full-range energy spectrum
Smith-Johnsen, Christine; Tyssøy, Hilde Nesse; Hendrickx, Koen; Orsolini, Yvan; Kishore Kumar, Grandhi; Ødegaard, Linn-Kristine Glesnes; Sandanger, Marit Irene; Stordal, Frode; Megner, Linda (Peer reviewed; Journal article, 2017)In April 2010, a coronal mass ejection and a corotating interaction region on the Sun resulted in an energetic electron precipitation event in the Earth’s atmosphere. We investigate direct and indirect nitric oxide (NO) ... -
The Direct Effect of Medium Energy Electron Precipitation on Mesospheric Dynamics During a Sudden Stratospheric Warming Event in 2010
Zuniga Lopez, Hector Daniel; Tyssøy, Hilde Nesse; Smith-Johnsen, Christine; Maliniemi, Ville Aleksi (Journal article; Peer reviewed, 2022)Medium energy electron (MEE) (30–1,000 keV) precipitation enhances the production of nitric (NOx) and hydrogen oxides (HOx) throughout the mesosphere, which can destroy ozone (O3) in catalytic reactions. The dynamical ... -
Effects of enhanced downwelling of NOx on Antarctic upper-stratospheric ozone in the 21st century
Maliniemi, Ville Aleksi; Tyssøy, Hilde Nesse; Smith-Johnsen, Christine; Arsenovic, Pavle; Marsh, Daniel R. (Journal article; Peer reviewed, 2021)Ozone is expected to fully recover from the chlorofluorocarbon (CFC) era by the end of the 21st century. Furthermore, because of anthropogenic climate change, a cooler stratosphere decelerates ozone loss reactions and is ... -
Exploring the Predictability of the High-Energy Tail of MEE Precipitation Based on Solar Wind Properties
Salice, Josephine Alessandra; Nesse, Hilde; Babu, Eldho Midhun; Smith-Johnsen, Christine; Richardson, Ian (Journal article; Peer reviewed, 2023)Medium Energy Electron (MEE) precipitation (≳30 keV) ionizes the mesosphere and initiates chemical reactions, which ultimately can reduce mesospheric and stratospheric ozone. Currently, there are considerable differences ... -
HEPPA III Intercomparison Experiment on Electron Precipitation Impacts: 1. Estimated Ionization Rates During a Geomagnetic Active Period in April 2010
Tyssøy, Hilde Nesse; Sinnhuber, M.; Asikainen, T.; Bender, Stefan; Clilverd, M.A.; Funke, B.; van de Kamp, M.; Pettit, J.M.; Randall, C.E.; Reddmann, T.; Rodger, C.J.; Rozanov, E.; Smith-Johnsen, Christine; Sukhodolov, T.; Verronen, P.T.; Wissing, J.M.; Yakovchuk, O. (Journal article; Peer reviewed, 2022)Precipitating auroral and radiation belt electrons are considered an important part of the natural forcing of the climate system. Recent studies suggest that this forcing is underestimated in current chemistryclimate models. ... -
Heppa III Intercomparison Experiment on Electron Precipitation Impacts: 2. Model-Measurement Intercomparison of Nitric Oxide (NO) During a Geomagnetic Storm in April 2010
Sinnhuber, M.; Tyssøy, Hilde Nesse; Asikainen, T.; Bender, Stefan; Funke, B.; Hendrickx, K.; Pettit, J.M.; Reddmann, T.; Rozanov, E.; Schmidt, H.; Smith-Johnsen, Christine; Sukhodolov, T.; Szeląg, M.E.; van de Kamp, de; Verronen, P.T.; Wissing, J.M.; Yakovchuk, O.S. (Journal article; Peer reviewed, 2022)Precipitating auroral and radiation belt electrons are considered to play an important part in the natural forcing of the middle atmosphere with a possible impact on the climate system. Recent studies suggest that this ... -
Mesospheric nitric acid enhancements during energetic electron precipitation events simulated by WACCM‐D
Orsolini, Yvan; Smith-Johnsen, Christine; Marsh, Daniel R.; Stordal, Frode; Rodger, Craig J.; Verronen, Pekka T.; Clilverd, Mark A. (Peer reviewed; Journal article, 2018-07)While observed mesospheric polar nitric acid enhancements have been attributed to energetic particle precipitation through ion cluster chemistry in the past, this phenomenon is not reproduced in current whole‐atmosphere ... -
Mesospheric Nitric Oxide Transport in WACCM
Smith-Johnsen, Christine; Marsh, Daniel Robert; Smith, Anne K.; Tyssøy, Hilde Nesse; Maliniemi, Ville Aleksi (Journal article; Peer reviewed, 2022)Energetic particle precipitation (EPP) causes ionization of the main constituents of the Earth's atmosphere which leads to the production of nitric oxide (NO) throughout the polar mesosphere and lower thermosphere (MLT). ... -
Nitric Oxide Response to the April 2010 Electron Precipitation Event: Using WACCM and WACCM‐D With and Without Medium‐Energy Electrons
Smith-Johnsen, Christine; Marsh, Daniel R.; Orsolini, Yvan; Tyssøy, Hilde Nesse; Hendrickx, Koen; Sandanger, Marit Irene J.; Ødegaard, Linn-Kristine Glesnes; Stordal, Frode (Peer reviewed; Journal article, 2018-06-07)Energetic electrons from the magnetosphere deposit their energy in the atmosphere and lead to production of nitric oxide (NO) in the mesosphere and lower thermosphere. We study the atmospheric NO response to a geomagnetic ... -
Observations of Electron Precipitation During Pulsating Aurora and Its Chemical Impact
Kebede, Fasil Tesema; Partamies, Noora; Tyssøy, Hilde Nesse; Kero, Antti; Smith-Johnsen, Christine (Journal article; Peer reviewed, 2020)Pulsating auroras (PsAs) are low‐intensity diffuse aurora, which switch on and off with a quasiperiodic oscillation period from a few seconds to ∼10 s. They are predominantly observed after magnetic midnight, during the ... -
The Predictive Capabilities of the Auroral Electrojet Index for Medium Energy Electron Precipitation
Tyssøy, Hilde Nesse; Partamies, Noora; Babu, Eldho Midhun; Smith-Johnsen, Christine; Salice, Josephine Alessandra (Journal article; Peer reviewed, 2021)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 ... -
Production and transport mechanisms of NO in the polar upper mesosphere and lower thermosphere in observations and models
Hendrickx, Koen; Megner, Linda; Marsh, Daniel R.; Smith-Johnsen, Christine (Peer reviewed; Journal article, 2018-06-28)A reservoir of nitric oxide (NO) in the lower thermosphere efficiently cools the atmosphere after periods of enhanced geomagnetic activity. Transport from this reservoir to the stratosphere within the winter polar vortex ... -
Will Climate Change Impact Polar NOx Produced by Energetic Particle Precipitation?
Maliniemi, Ville Aleksi; Marsh, Daniel R.; Tyssøy, Hilde Nesse; Smith-Johnsen, Christine (Journal article; Peer reviewed, 2020)Energetic electron precipitation (EEP) is an important source of polar nitrogen oxides (NOx) in the upper atmosphere. During winter, mesospheric NOx has a long chemical lifetime and is transported to the stratosphere by ...