Effects of the September 2005 Solar Flares and Solar Proton Events on the Middle Atmosphere in WACCM

Pettit, Joshua; Randall, C. E.; Marsh, Daniel R.; Bardeen, Charles G.; Qian, Liying; Jackman, Charles H.; Woods, T. N.; Coster, A. J.; Harvey, V. Lynn

doi:10.1029/2018ja025294

Cited by 21 publications

(19 citation statements)

References 68 publications

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“…Each simulation used a horizontal grid of 2.5°× 1.875°(longitude × latitude), and a 30 min time step. Previous versions of WACCM have been used for a variety of purposes, such as simulating climate change between the industrial revolution and the twenty-first century [72], as well as investigating the effects of solar flares on the middle atmosphere [73]. This same model version has also previously been used in the context of exoplanets [74][75][76][77].…”

Section: Atmospheric Modelling Using Waccm6mentioning

confidence: 99%

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A revised lower estimate of ozone columns during Earth’s oxygenated history

et al. 2022

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The history of molecular oxygen (O 2 ) in Earth’s atmosphere is still debated; however, geological evidence supports at least two major episodes where O 2 increased by an order of magnitude or more: the Great Oxidation Event (GOE) and the Neoproterozoic Oxidation Event. O 2 concentrations have likely fluctuated (between 10 −3 and 1.5 times the present atmospheric level) since the GOE ∼2.4 Gyr ago, resulting in a time-varying ozone (O 3 ) layer. Using a three-dimensional chemistry-climate model, we simulate changes in O 3 in Earth’s atmosphere since the GOE and consider the implications for surface habitability, and glaciation during the Mesoproterozoic. We find lower O 3 columns (reduced by up to 4.68 times for a given O 2 level) compared to previous work; hence, higher fluxes of biologically harmful UV radiation would have reached the surface. Reduced O 3 leads to enhanced tropospheric production of the hydroxyl radical (OH) which then substantially reduces the lifetime of methane (CH 4 ). We show that a CH 4 supported greenhouse effect during the Mesoproterozoic is highly unlikely. The reduced O 3 columns we simulate have important implications for astrobiological and terrestrial habitability, demonstrating the relevance of three-dimensional chemistry-climate simulations when assessing paleoclimates and the habitability of faraway worlds.

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Section: Atmospheric Modelling Using Waccm6mentioning

confidence: 99%

“…Additionally, the real atmosphere is three-dimensional and varies temporally, and the O 3 layer can be influenced by biologically produced gases (e.g. O 2 , CH 4 ), asteroid or comet impacts [138], solar activity and flares [73], as well as volcanic emissions [61].…”

Section: Habitability and Increased Uv Radiationmentioning

confidence: 99%

A revised lower estimate of ozone columns during Earth’s oxygenated history

et al. 2022

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“…However, Jackman et al (2011) show that higher energies contribute very little to the total ozone or NO y impact. We only consider protons, and not the X-ray flares that are associated with some SPEs -in the polar regions we can assume that the proton effect is the dominant one, at least for large SPEs (Pettit et al, 2018).…”

Section: Waccm-d Simulationsmentioning

confidence: 99%

Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: the importance of lower ionospheric chemistry

et al. 2020

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Abstract. Atmospheric effects of solar proton events (SPEs) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, odd hydrogen and odd nitrogen are produced during SPEs, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the strongest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e., in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase in mesospheric HNO3 or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 strongest SPEs which occurred in the years 1989–2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O3, HOx (OH + HO2), Clx (Cl + ClO), HNO3, NOx (NO + NO2) and H2O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O3 and NOx and a weaker response in HOx and introduces changes in HNO3 and Clx. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.

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Section: Waccm-d Simulationsmentioning

confidence: 99%

Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: importance of lower ionospheric chemistry

Kalakoski¹,

Verronen²,

Seppälä³

et al. 2020

Preprint

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Abstract. Atmospheric effects of solar proton events (SPE) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, SPEs cause production of odd hydrogen and odd nitrogen, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the largest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e. in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase of mesospheric HNO3 or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 largest SPEs that occurred in years 1989&#8211;2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O3, HOx (OH&#8201;+&#8201;HO2), Clx (Cl&#8201;+&#8201;ClO), HNO3, NOx (NO&#8201;+&#8201;NO2) and H2O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O3 and NOx, weaker response in HOx and introduces changes in HNO3 and Clx. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.

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Effects of the September 2005 Solar Flares and Solar Proton Events on the Middle Atmosphere in WACCM

Cited by 21 publications

References 68 publications

A revised lower estimate of ozone columns during Earth’s oxygenated history

A revised lower estimate of ozone columns during Earth’s oxygenated history

Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: the importance of lower ionospheric chemistry

Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: importance of lower ionospheric chemistry

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