ASSESSING RADIATION EXPOSURE INSIDE THE EARTH’S ATMOSPHERE

2020 ◽  
Vol 190 (4) ◽  
pp. 427-436
Author(s):  
Anastasia Tezari ◽  
Pavlos Paschalis ◽  
Helen Mavromichalaki ◽  
Pantelis Karaiskos ◽  
Norma Crosby ◽  
...  
Keyword(s):  
Situational Awareness ◽  
European Space Agency ◽  
Software Application ◽  
Dose Rates ◽  
Earth’S Atmosphere ◽  
Service Centre ◽  
Space Agency ◽  
Earth's Atmosphere ◽  
New Feature

Abstract The study of the particle showers created inside the Earth’s atmosphere due to interactions of cosmic rays of solar and galactic origin is of great importance for the determination of the radiation impact on technological and biological systems. DYASTIMA is a Geant4-based software application that simulates the evolution of secondary particle cascades inside the atmosphere of Earth. DYASTIMA-R is a new feature especially created for assessing the exposure of flight-personnel and frequent flyers to cosmic radiation by performing calculations of radiobiological quantities, such as dose and equivalent dose rates for several air-flight scenarios. In this work, the validation of DYASTIMA/DYASTIMA-R, according to internationally accepted ICRP and ICRU standards, is discussed. Initial results for radiobiological quantities for several air-flight scenarios are also included. The results for specific scenarios calculated by DYASTIMA/DYASTIMA-R are provided as a federated product through the European Space Agency Space Situational Awareness Space Weather Service Centre Network.

scholarly journals Cosmic radiation exposure of aviators for solar cycles 23 and 24

2021 ◽  
pp. 109-113
Author(s):  
Pavlos Paschalis ◽  
Anastasia Tezari ◽  
Helen Mavromichalaki ◽  
Pantelis Karaiskos ◽  
Norma Crosby ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Situational Awareness ◽  
European Space Agency ◽  
Cosmic Ray ◽  
Solar Cycles ◽  
Cosmic Ray Intensity ◽  
Software Application ◽  
Dose Rates ◽  
Space Agency ◽  
Ambient Dose Equivalent

Assessing the radiation exposure of aviators and frequent flyers requires the study of the cosmic ray showers inside the Earth’s atmosphere. DYASTIMA / DYASTIMA-R is a Geant4 based software application, implemented by the Athens Cosmic Ray Group which allows the study of the evolving secondary particles cascades inside the atmosphere, as well as radiation dosimetry calculations (ambient dose equivalent rate) at different atmosphe - ric altitudes, geographic coordinates and magnetic cut-off rigidity. Results for various scenarios, as calculated by DYASTIMA/DYASTIMA-R, are provided as a federated product through the European Space Agency Space Situational Awareness of the Space Radiation Service Centre Network, while the DYASTIMA software is provi- ded through the Athens Neutron Monitor Station (A.Ne.Mo.S.) portal. Initial results for the assessment of the radiation exposure during the last Solar Cycles 23 and 24 are presented in this work, covering the most usual flying altitudes. The results indicate the dependence of the dose rate on the magnetic cut-off rigidity threshold, with higher dose rates at high geographic latitudes, as well as the anti-correlation of cosmic ray intensity with the solar activity, as higher dose rates are observed during solar minimum conditions.

scholarly journals ESA’s Gaia mission: a billion stars with a billion pixels

Photoniques ◽  
2019 ◽  
pp. 38-43
Author(s):  
Jos De Bruijne ◽  
Matthias Erdmann
Keyword(s):  
European Space Agency ◽  
Earth’S Atmosphere ◽  
Space Agency ◽  
Hipparcos Catalogue ◽  
Celestial Bodies ◽  
Earth's Atmosphere ◽  
Astrometric Data

Astrometry is the astronomical discipline of measuring the positions, and changes therein, of celestial bodies. Accurate astrometry from the ground is limited by the blurring effects induced by the Earth’s atmosphere. Since decades, Europe has been at the forefront of making astrometric measurements from space. The European Space Agency (ESA) launched the first satellite dedicated to astrometry, named Hipparcos, in 1989, culminating in the release of the Hipparcos Catalogue containing astrometric data for 117 955 stars in 1997. Since mid 2014, Hipparcos’ successor, Gaia, has been collecting astrometric data, with a 100 times improved precision, for 10 000 times as many stars.

scholarly journals Daedalus: A Low-Flying Spacecraft for the Exploration of the Lower Thermosphere - Ionosphere

2019 ◽  
Author(s):  
Theodoros E. Sarris ◽  
Elsayed R. Talaat ◽  
Minna Palmroth ◽  
Iannis Dandouras ◽  
Errico Armandillo ◽  
...  
Keyword(s):  
Lower Thermosphere ◽  
European Space Agency ◽  
Upper Atmosphere ◽  
Mission Design ◽  
Earth’S Atmosphere ◽  
Ion Drift ◽  
Space Agency ◽  
Electric And Magnetic Fields ◽  
Precipitation Estimates ◽  
Earth's Atmosphere

Abstract. The Daedalus mission has been proposed to the European Space Agency (ESA) in response to the call for ideas for the Earth Observation programme's 10th Earth Explorer. It was selected in 2018 as one of three candidates for a Phase-0 feasibility study. The goal of the mission is to quantify the key electrodynamic processes that determine the structure and composition of the upper atmosphere, the gateway between the Earth’s atmosphere and space. An innovative preliminary mission design allows Daedalus to access electrodynamics processes down to altitudes of 150 km and below. Daedalus will perform in-situ measurements of plasma density and temperature, ion drift, neutral density and wind, ion and neutral composition, electric and magnetic fields and precipitating particles. These measurements will unambiguously quantify the amount of energy deposited in the upper atmosphere during active and quiet geomagnetic times via Joule heating and energetic particle precipitation, estimates of which currently vary by orders of magnitude between models. An innovation of the Daedalus preliminary mission concept is that it includes the release of sub-satellites at low altitudes: combined with the main spacecraft, these sub-satellites will provide multi-point measurements throughout the Lower Thermosphere-Ionosphere region, down to altitudes below 120 km, in the heart of the most under-explored region in the Earth's atmosphere. This paper describes Daedalus as originally proposed to ESA.

scholarly journals Daedalus: a low-flying spacecraft for in situ exploration of the lower thermosphere–ionosphere

2020 ◽  
Vol 9 (1) ◽  
pp. 153-191 ◽  
Author(s):  
Theodoros E. Sarris ◽  
Elsayed R. Talaat ◽  
Minna Palmroth ◽  
Iannis Dandouras ◽  
Errico Armandillo ◽  
...  
Keyword(s):  
Lower Thermosphere ◽  
European Space Agency ◽  
Upper Atmosphere ◽  
Mission Design ◽  
Earth’S Atmosphere ◽  
Space Agency ◽  
Observation Methods ◽  
Precipitation Estimates ◽  
Earth's Atmosphere

Abstract. The Daedalus mission has been proposed to the European Space Agency (ESA) in response to the call for ideas for the Earth Observation program's 10th Earth Explorer. It was selected in 2018 as one of three candidates for a phase-0 feasibility study. The goal of the mission is to quantify the key electrodynamic processes that determine the structure and composition of the upper atmosphere, the gateway between the Earth's atmosphere and space. An innovative preliminary mission design allows Daedalus to access electrodynamics processes down to altitudes of 150 km and below. Daedalus will perform in situ measurements of plasma density and temperature, ion drift, neutral density and wind, ion and neutral composition, electric and magnetic fields, and precipitating particles. These measurements will unambiguously quantify the amount of energy deposited in the upper atmosphere during active and quiet geomagnetic times via Joule heating and energetic particle precipitation, estimates of which currently vary by orders of magnitude between models and observation methods. An innovation of the Daedalus preliminary mission concept is that it includes the release of subsatellites at low altitudes: combined with the main spacecraft, these subsatellites will provide multipoint measurements throughout the lower thermosphere–ionosphere (LTI) region, down to altitudes below 120 km, in the heart of the most under-explored region in the Earth's atmosphere. This paper describes Daedalus as originally proposed to the ESA.

scholarly journals Observations of the Leonids in Central Asia

1998 ◽  
Vol 11 (2) ◽  
pp. 1022-1022
Author(s):  
P.B. Babadzhanov
Keyword(s):  
Central Asia ◽  
Density Range ◽  
Dust Grains ◽  
Earth’S Atmosphere ◽  
Earth's Atmosphere

Observations in Central Asia in 1965-1966 by both photographic and radar methods allowed a determination of the radiants and orbits of Leonids (Babadzhanov and Getman 1970). Photographs showed that meteoroids undergo quasi-continuous fragmentation (QCF) in the Earth’s atmosphere. Taking account of QCF, the density of the Leonid meteoroids were found to lie between 1 and Agcm-3 the average being 2gcm-3 (Babadzhanov 1994), in agreement with the density range of between 0.2 and 6gcm-3 given by Maas et al (1990) for dust grains from comet P/1 Halley, with values below 0.6 being rare. Further, the icy grains have a density of about 1gcm-3 while silicate grains have a mean density 2.5 times higher.

Remote sensing of snow and atmosphere properties using Ocean and Land Colour Instrument on board Copernicus Sentinel-3 mission

2020 ◽  
Author(s):  
Alexander Kokhanovsky ◽  
Jason Box ◽  
Baptiste Vandecrux ◽  
Michael Kern
Keyword(s):  
Remote Sensing ◽  
Atmospheric Correction ◽  
European Space Agency ◽  
Satellite Observations ◽  
Snow Properties ◽  
Retrieval Technique ◽  
Space Agency ◽  
Correction Technique ◽  
Cloud Screening

<p><span>In this work we propose a simple technique to derive snow and atmosphere properties from satellite top-of-atmosphere spectral reflectance observations using asymptotic radiative transfer theory valid for the case of weakly absorbing and optically thick media. The following snow properties are derived and analyzed: ice grain size, snow specific surface area, snow pollution load, snow spectral and broadband albedo. The developed retrieval technique includes both atmospheric correction and cloud screening routines and is based on Ocean and Land Colour Instrument (OLCI) measurements on board Sentinel-3A, B. The spectral aerosol optical thickness, total ozone and water vapour column are derived fitting the measured and simulated OLCI-registered spectral reflectances at 21 OLCI channels.</span></p><p><span>The derived results are validated using ground - based observations. It follows that satellite observations can be used to study time series of spectral and broadband albedo over Greenland. The deviations of satellite and ground observations are due to problems with cloud screening over snow and also due to different spatial scale of satellite and ground observations (Kokhanovsky et al., 2020).</span></p><p>Acknowledgements</p><p>The work has been supported by the European Space Agency in the framework of ESRIN contract No. 4000118926/16/I-NB ‘Scientific Exploitation of Operational Missions (SEOM) Sentinel-3 Snow (Sentinel-3 for Science, Land Study 1: Snow’) and ESRIN contract 4000125043 – ESA/AO/1-9101/17/I-NB EO science for society ‘Pre-operational Sentinel-3 snow and ice products’.</p><p><span>References</span></p><p>Kokhanovsky, A.A., et al. (2020), The determination of snow albedo from satellite observations using fast atmospheric correction technique, Remote Sensing, 12 (2), 234,  https://doi.org/10.3390/rs12020234.</p>

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