Atmocosmics: A Geant 4 Code for Computing the Interaction of Cosmic Rays With the Earth's Atmosphere

Desorgher, L.; Flückiger, E. O.; Gurtner, M.; Möser, Michael; Bütikofer, R.

doi:10.1142/s0217751x05030132

Cited by 155 publications

(146 citation statements)

References 2 publications

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“…Accordingly, we use a full Monte Carlo model, CRAC:CRII (Usoskin and Kovaltsov, 2006;Usoskin et al, 2010), based on the CORSIKA Monte Carlo package. A similar result can be obtained with the PLANETOCOSMIC (Desorgher et al, 2005) based on the GEANT package. The agreement between the two models has been verified (Usoskin et al, 2009) to be within 10 %.…”

Section: Galactic Cosmic Rayssupporting

confidence: 81%

Solar forcing for CMIP6 (v3.2)

et al. 2017

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Abstract. This paper describes the recommended solar forcing dataset for CMIP6 and highlights changes with respect to CMIP5. The solar forcing is provided for radiative properties, namely total solar irradiance (TSI), solar spectral irradiance (SSI), and the F10.7 index as well as particle forcing, including geomagnetic indices Ap and Kp, and ionization rates to account for effects of solar protons, electrons, and galactic cosmic rays. This is the first time that a recommendation for solar-driven particle forcing has been provided for a CMIP exercise. The solar forcing datasets are provided at daily and monthly resolution separately for the CMIP6 preindustrial control, historical (1850CMIP6 preindustrial control, historical ( -2014, and future (2015-2300) simulations. For the preindustrial control simulation, both constant and time-varying solar forcing components are provided, with the latter including variability on 11-year and shorter timescales but no long-term changes. For the future, we provide a realistic scenario of what solar behavior could be, as well as an additional extreme Maunderminimum-like sensitivity scenario. This paper describes the forcing datasets and also provides detailed recommendations as to their implementation in current climate models.For the historical simulations, the TSI and SSI time series are defined as the average of two solar irradiance models that are adapted to CMIP6 needs: an empirical onePublished by Copernicus Publications on behalf of the European Geosciences Union. A new and lower TSI value is recommended: the contemporary solar-cycle average is now 1361.0 W m −2 . The slight negative trend in TSI over the three most recent solar cycles in the CMIP6 dataset leads to only a small global radiative forcing of −0.04 W m −2 . In the 200-400 nm wavelength range, which is important for ozone photochemistry, the CMIP6 solar forcing dataset shows a larger solar-cycle variability contribution to TSI than in CMIP5 (50 % compared to 35 %).We compare the climatic effects of the CMIP6 solar forcing dataset to its CMIP5 predecessor by using timeslice experiments of two chemistry-climate models and a reference radiative transfer model. The differences in the long-term mean SSI in the CMIP6 dataset, compared to CMIP5, impact on climatological stratospheric conditions (lower shortwave heating rates of −0.35 K day −1 at the stratopause), cooler stratospheric temperatures (−1.5 K in the upper stratosphere), lower ozone abundances in the lower stratosphere (−3 %), and higher ozone abundances (+1.5 % in the upper stratosphere and lower mesosphere). Between the maximum and minimum phases of the 11-year solar cycle, there is an increase in shortwave heating rates (+0.2 K day −1 at the stratopause), temperatures (∼ 1 K at the stratopause), and ozone (+2.5 % in the upper stratosphere) in the tropical upper stratosphere using the CMIP6 forcing dataset. This solar-cycle response is slightly larger, but not statistically significantly different from that for the CMIP5 forcing dataset.CMIP6 models wi...

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Section: Galactic Cosmic Rayssupporting

confidence: 81%

Solar forcing for CMIP6 (v3.2)

et al. 2017

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“…For the computation of NM cut-off rigidity and asymptotic cones we used the MAGNETOCOSMICS code (Desorgher et al, 2005). We employed a combination of the geomagnetic model IGRF (epoch, 2015) (Macmillan et al, 2003) as the internal field and the Tsyganenko 89 model (Tsyganenko, 1989) for the external field.…”

Section: General Description Of the Methodsmentioning

confidence: 99%

Assessment of spectral and angular characteristics of sub-GLE events using the global neutron monitor network

Mishev

Poluianov

Usoskin

2017

J. Space Weather Space Clim.

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-New recently installed high-altitude polar neutron monitors (NMs) have made the worldwide NM network more sensitive to strong solar energetic particle (SEP) events, registered at ground level, namely ground-level enhancement (GLE) events. The DOMC/B and South Pole NMs in addition to marginal cut-off rigidity also possess lower atmospheric cut-off compared to the sea level. As a result, the two high-altitude polar NM stations are able to detect lower energy SEP events, which most likely would not be registered by the other (near sea level) NMs. Here, we consider several candidates for such type of events called sub-GLEs. Using the worldwide NM database (NMDB) records and an optimization procedure combined with simulation of the global NM network response, we assess the spectral and angular characteristics of sub-GLE particles. With the estimated spectral characteristics as an input, we evaluate the effective dose rate in polar and sub-polar regions at typical commercial flight altitude. Hence, we demonstrate that the global NM network is a useful tool to estimate important space weather effects, e.g., the aircrew exposure due to cosmic rays of galactic and/or solar origins.

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“…The PLANETOCOSMICS code (http://cosray.unibe.ch/ ∼laurent/planetocosmics) is a Geant4 application originally designed to compute the electromagnetic and hadronic interaction of energetic particles (<1 TeV) with the Earth, Mars and Mercury, taking the respective planetary atmosphere, magnetic field, and soil into account (Desorgher et al 2005;Bütikofer et al 2008). The code was developed so that the implementation of new atmospheric and magnetic field models, as well as the extension to other planetary environments, is rather simple.…”

Section: The Planetocosmics Modelmentioning

confidence: 99%

Ionization processes in the atmosphere of Titan

Gronoff¹,

Lilensten²,

Desorgher

et al. 2009

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Context. The Cassini probe regularly passes in the vicinity of Titan, revealing new insights into particle precipitation thanks to the electron and proton spectrometer. Moreover, the Huygens probe has revealed an ionized layer at 65 km induced by cosmic rays. The impact of these different particles on the chemistry of Titan is probably very strong. Aims. In this article, we compute the whole ionization in the atmosphere of Titan: from the cosmic rays near the ground to the EUV in the upper atmosphere. The meteoritic layer is not taken into account. Methods. We used the transTitan model to compute the electron and EUV impact, and the planetocosmics code to compute the influence of protons and oxygen ions. We coupled the two models to study the influence of the secondary electrons obtained by planetocosmics through the transTitan code. The resulting model improves the accuracy of the calculation through the transport of electrons in the atmosphere. Results. The whole ionization is computed and studied in details. During the day, the cosmic ray ionization peak is as strong as the UV-EUV one. Electrons and protons are very important depending the precipitation conditions. Protons can create a layer at 500 km, while electrons tend to ionize near 800 km. The oxygen ion impact is near 900 km. The results shows few differences to precedent models for the nightside T5 fly-by of Cassini, and can highlight the sources of the different ion layers detected by radio measurements. Conclusions. The new model successfully computes the ion production in the atmosphere of Titan. For the first time, a full electron and ion profile has been computed from 0 to 1600 km, which compares qualitatively with measurements. This result can be used by chemical models.

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Atmocosmics: A Geant 4 Code for Computing the Interaction of Cosmic Rays With the Earth's Atmosphere

Cited by 155 publications

References 2 publications

Solar forcing for CMIP6 (v3.2)

Solar forcing for CMIP6 (v3.2)

Assessment of spectral and angular characteristics of sub-GLE events using the global neutron monitor network

Ionization processes in the atmosphere of Titan

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