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>

scholarly journals HEPPA III intercomparison experiment on electron precipitation impacts:  Estimated ionization rates during a geomagnetic active period in April 2010

2021 ◽  
Author(s):  
Hilde Nesse Tyssøy ◽  
Miriam Sinnhuber ◽  
Timo Asikainen ◽  
Stefan Bender ◽  
Mark A. Clilverd ◽  
...  
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Ionization Rate ◽  
Data Sets ◽  
Active Period ◽  
Medium Energy ◽  
Model Driven ◽  
Wide Range ◽  
Order Of Magnitude ◽  
Ionization Rates

<p>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 chemistry-climate models. The HEPPA III intercomparison experiment is a collective effort to address this point. Here, eight different estimates of medium energy electron (MEE) (>30 keV) ionization rates are assessed during a geomagnetic active period in April 2010.  The objective is to understand the potential uncertainty related to the MEE energy input. The ionization rates are all based on the Medium Energy Proton and Electron Detector (MEPED) on board the NOAA/POES and EUMETSAT/MetOp spacecraft series. However, different data handling, ionization rate calculations, and background atmospheres result in a wide range of mesospheric electron ionization rates. Although the eight data sets agree well in terms of the temporal variability, they differ by about an order of magnitude in ionization rate strength both during geomagnetic quiet and disturbed periods. The largest spread is found in the aftermath of the geomagnetic activity.  Furthermore, governed by different energy limits, the atmospheric penetration depth varies, and some differences related to latitudinal coverage are also evident. The mesospheric NO densities simulated with the Whole Atmospheric Community Climate Model driven by highest and lowest ionization rates differ by more than a factor of eight. In a follow-up study, the atmospheric responses are simulated in four chemistry-climate models and compared to satellite observations, considering both the model structure and the ionization forcing.</p>

Sir William Ian Axford. 2 January 1933 — 13 March 2010

2013 ◽  
Vol 59 ◽  
pp. 5-31 ◽  
Author(s):  
William Allan
Keyword(s):  
Solar Wind ◽  
New Zealand ◽  
Solar System ◽  
Cosmic Ray ◽  
Space Physics ◽  
Max Planck ◽  
Cornell University ◽  
Wide Range ◽  
Defence Research ◽  
The University

William Ian Axford was born and educated in New Zealand, receiving his ME and MSc degrees from Canterbury College of the University of New Zealand in 1956. He completed his PhD at Manchester University in 1960 and spent the following year at Cambridge University before moving to the Defence Research Board of Canada. From 1963 to 1974 he held professorships at Cornell University and the University of California at San Diego. From 1974 to 2001 he directed the Max Planck Institute for Aeronomy in Germany, with two three-year periods of leave in New Zealand in 1982–85 and 1992–95. Ian Axford was one of the greatest plasma physicists of the space age. He made fundamental contributions to a wide range of topics in the fields of space physics and astrophysics, including the dynamics of the Earth’s magnetosphere, the magnetic field reconnection process, the Sun’s atmosphere and the formation and evolution of the solar wind, the interaction of the solar wind with the interstellar medium and with comets, cosmic ray propagation and modulation in the Solar System, the acceleration of cosmic rays in supernova shocks, and the use of robotic spacecraft in the exploration of the Solar System. Ian was also a remarkable science administrator, completely restructuring the Max Planck Institute for Aeronomy and transforming it into one of the world’s leading space and atmospheric research institutes. He was a great advocate of international collaboration in science, and reinvigorated several flagging institutions such as the European Geophysical Society and the International Council of Scientific Unions Committee on Space Research.

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 Impact of middle range energy electron precipitations on polar winter ozone losses

2019 ◽  
Vol 127 ◽  
pp. 01005
Author(s):  
Kseniia Golubenko ◽  
Irina Mironova ◽  
Eugene Rozanov
Keyword(s):  
Coupled Model ◽  
Energy Electron ◽  
Atmospheric Response ◽  
Ion Chemistry ◽  
Polar Night ◽  
Middle Range ◽  
Intercomparison Project ◽  
Odd Nitrogen ◽  
Convective Model ◽  
Ionization Rates

In this paper we present the study of polar winter atmospheric response to middle range energy electron precipitations. We analse the variability of the odd nitrogen group NOx, hydrogen group HOx in the polar wonter atmosphere and estimate the ozone (O3) depletion caused by the middle range energy electron precipitations. For the study we exploit 1-D radiative-convective model with interactive neutral and ion chemistry. Ionization rates induced by middle-energy electrons were taken from the CMIP6 (Coupled Model Intercomparison Project Phase 6) solar forcing dataset. The atmospheric response to ionization rates induced by middleenergy electrons during polar night consists of increase of mesospheric HOx by 0.1-0.4 ppbv and NOx by 10-90 ppbv driving ozone losses up to 5% over zonal band of about 750 NH.

scholarly journals Promoting Independent Language Learning Cross-Campus at the University of Leeds through a Self-Access Area

2013 ◽  
pp. 367-371
Author(s):  
Carolin Schneider
Keyword(s):  
Language Learning ◽  
Language Learners ◽  
Full Range ◽  
The Self ◽  
Human Interaction ◽  
Wide Range ◽  
Language Courses ◽  
Library Catalogue ◽  
Online Library ◽  
The University

The Language Centre at the University of Leeds concentrates on the full range of language training and preparation courses, both for pre-sessional and for current university students. These courses relate both to the learning of English and of foreign languages. The Self-Access Area constitutes the Language Centre’s resource library for language learning materials and supports learners on Language Centre and other modern language courses, as well as independent language learners from across the university. Catering for approximately 11,000 users, the Self-Access Area opens, on average, for 46 hours per week, with evening and Saturday opening times during term time and exam weeks. Among the services that the Self-Access Area provides are a wide range of language learning resources in print and various audiovisual formats, induction tours, an up-to-date online library catalogue and a social media presence. As part of the Language Centre, the Self-Access Area team is connected with staff and students across the university. The service also offers a range of opportunities which encourage human interaction both amongst language learners and between learners and specialists. It also acts as a flexible social and study space.

TEM study of boron additions to cobalt aluminide

1988 ◽  
Vol 46 ◽  
pp. 546-547
Author(s):  
Gerald B. Feldewerth
Keyword(s):  
High Temperature ◽  
Turbine Engines ◽  
Major Drawback ◽  
University Of Missouri ◽  
Specific Strength ◽  
Aerospace Applications ◽  
Wide Range ◽  
Ordered Alloys ◽  
The University ◽  
Very High

In recent years an increasing emphasis has been placed on the study of high temperature intermetallic compounds for possible aerospace applications. One group of interest is the B2 aiuminides. This group of intermetaliics has a very high melting temperature, good high temperature, and excellent specific strength. These qualities make it a candidate for applications such as turbine engines. The B2 aiuminides exist over a wide range of compositions and also have a large solubility for third element substitutional additions, which may allow alloying additions to overcome their major drawback, their brittle nature.One B2 aluminide currently being studied is cobalt aluminide. Optical microscopy of CoAl alloys produced at the University of Missouri-Rolla showed a dramatic decrease in the grain size which affects the yield strength and flow stress of long range ordered alloys, and a change in the grain shape with the addition of 0.5 % boron.

Biodiversity in Vegetation and Ecosystems»: symposium on the occasion of the retirement of Prof. Dr. Fred J.A. Daniels (Munster, Germany, July 11, 2008)

2008 ◽  
pp. 123-124
Author(s):  
N. V. Matveyeva
Keyword(s):  
Wide Range ◽  
65Th Anniversary ◽  
The University

July 2008 in Münster (Germany) hosted a Symposium on the occasion of the 65th anniversary of Professor of the University of this city, Fred Daniels (Frederikus Josephus Alphonsus Daniëls). The title of this Symposium «Biodiversity in Vegetation and Ecosystems» reflected the wide range of interests of the celebrant.

Tassos Papacostas and Maria Parani (eds.), Discipuli dona ferentes. Glimpses of Byzantium in Honour of Marlia Mundell Mango. Β υζ ά ν τ ι ο ς. Studies in Byzantine History and Civilization 11. Turnhout: Brepols Publishers, 2017. XXX, 486, 111 b/w figures.

Mediaevistik ◽  
2020 ◽  
Vol 32 (1) ◽  
pp. 333-337
Author(s):  
Natalia Teteriatnikov
Keyword(s):  
Late Antiquity ◽  
Oxford University ◽  
Present Volume ◽  
Wide Range ◽  
Byzantine Period ◽  
The University ◽  
Vast Territory ◽  
Byzantine History

The present volume is a tribute to Marlia Mango on the occasion of her retirement from the University service of Kings College, Oxford University. All essays, written by her students, offer the result of their research and express a profound gratitude to their teacher. The essays tackle a wide range of subjects covering a vast territory from Constantinople to its periphery as well as Italy. Chronologically diverse, research materials span from late antiquity to the late Byzantine period.

The Major Transitions in Evolution

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Full Range ◽  
Evolution Of Cooperation ◽  
Major Transitions ◽  
Insect Societies ◽  
Wide Range ◽  
Major Transition ◽  
Life Itself ◽  
History Of ◽  
Emergence Of Cooperation ◽  
Multicellular Organisms

Over the history of life there have been several major changes in the way genetic information is organized and transmitted from one generation to the next. These transitions include the origin of life itself, the first eukaryotic cells, reproduction by sexual means, the appearance of multicellular plants and animals, the emergence of cooperation and of animal societies, and the unique language ability of humans. This ambitious book provides the first unified discussion of the full range of these transitions. The authors highlight the similarities between different transitions--between the union of replicating molecules to form chromosomes and of cells to form multicellular organisms, for example--and show how understanding one transition sheds light on others. They trace a common theme throughout the history of evolution: after a major transition some entities lose the ability to replicate independently, becoming able to reproduce only as part of a larger whole. The authors investigate this pattern and why selection between entities at a lower level does not disrupt selection at more complex levels. Their explanation encompasses a compelling theory of the evolution of cooperation at all levels of complexity. Engagingly written and filled with numerous illustrations, this book can be read with enjoyment by anyone with an undergraduate training in biology. It is ideal for advanced discussion groups on evolution and includes accessible discussions of a wide range of topics, from molecular biology and linguistics to insect societies.

Oxford Studies in Medieval Philosophy Volume 7

2019 ◽  
Keyword(s):  
Late Antiquity ◽  
Full Range ◽  
Current Work ◽  
Medieval Philosophy ◽  
Original Essays ◽  
Wide Range ◽  
Extended Review

Oxford Studies in Medieval Philosophy annually collects the best current work in the field of medieval philosophy. The various volumes print original essays, reviews, critical discussions, and editions of texts. The aim is to contribute to an understanding of the full range of themes and problems in all aspects of the field, from late antiquity into the Renaissance, and extending over the Jewish, Islamic, and Christian traditions. Volume 6 includes work on a wide range of topics, including Davlat Dadikhuda on Avicenna, Christopher Martin on Abelard’s ontology, Jeremy Skrzypek and Gloria Frost on Aquinas’s ontology, Jean‐Luc Solère on instrumental causality, Peter John Hartman on Durand of St.‐Pourçain, and Kamil Majcherek on Chatton’s rejection of final causality. The volume also includes an extended review of Thomas Williams of a new book on Aquinas’s ethics by Colleen McCluskey.

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