WACCM‐D—Improved modeling of nitric acid and active chlorine during energetic particle precipitation

Szeląg, Monika E.; Verronen, Pekka T.; Marsh, Daniel R.; Päivärinta, S.-M.; Plane, J. M. C.

doi:10.1002/2015jd024173

Cited by 41 publications

(94 citation statements)

References 47 publications

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“…In the SH, the daily-varying enhancements also occur when the HNO 3 abundance is increasing as the winter approaches, while it is decreasing in the NH (see Figure 1). Figure 2 (right), we note that the HNO 3 increase due to the April 2010 EEP event in WACCM-D is much smaller than the corresponding increase after the January 2005 SPE, discussed by Andersson et al (2016). They found an increase in HNO 3 of 0.5-1.0 ppb near 70-75 km during the SPE (their Figure 9, top) in the NH.…”

Section: Monthly Mean Polar-averaged Distributions Of Ion Clustersmentioning

confidence: 71%

“…This variant of WACCM called WACCM-D, where D stands for the D-layer of the ionosphere (below the mesopause), is described in detail by Verronen et al (2016). Andersson et al (2016) investigated the chemical effects of the SPE of 2005, in particular on HNO 3 , and showed that the production of HNO 3 increased by 2 orders of magnitude between 40 and 70 km, bringing WACCM-D closer to the MLS satellite observations. The aim of this paper is to investigate, through a case study, the effect of EEP events on the distribution of HNO 3 and relevant ion clusters in the new WACCM-D model in comparison to the standard WACCM, in the presence of medium-to-high energy electron (MEE) forcing.…”

Section: Introductionmentioning

confidence: 99%

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Mesospheric Nitric Acid Enhancements During Energetic Electron Precipitation Events Simulated by WACCM‐D

et al. 2018

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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 chemistry-climate models. We investigate such nitric acid enhancements resulting from energetic electron precipitation events using a recently developed variant of the Whole Atmosphere Community Climate Model (WACCM) that includes a sophisticated ion chemistry tailored for the D-layer of the ionosphere (50-90 km), namely, WACCM-D. Using the specified dynamics mode, that is, nudging dynamics in the troposphere and stratosphere to meteorological reanalyses, we perform a 1-year-long simulation (July 2009-June 2010) and contrast WACCM-D with the standard WACCM. Both WACCM and WACCM-D simulations are performed with and without forcing from medium-to-high energy electron precipitation, allowing a better representation of the energetic electrons penetrating into the mesosphere. We demonstrate the effects of the strong particle precipitation events which occurred during April and May 2010 on nitric acid and on key ion cluster species, as well as other relevant species of the nitrogen family. The 1-year-long simulation allows the event-related changes in neutral and ionic species to be placed in the context of their annual cycle. We especially highlight the role played by medium-to-high energy electrons in triggering ion cluster chemistry and ion-ion recombinations in the mesosphere and lower thermosphere during the precipitation event, leading to enhanced production of nitric acid and raising its abundance by 2 orders of magnitude from 10 À4 to a few 10 À2 ppb.Both SPEs and energetic electron precipitation (EEP) lead first to the formation of primary ions such as O + , O + 2 , N + 2 , and N + through dissociation and dissociative ionization. These ions are then involved in fast ionchemistry reactions, ultimately producing NO x and hydrogen oxides (HO x ; e.g., see Sinnhuber et al., 2012 for a review). The chemistry of ion clusters plays a key role in the production of the neutral nitrogen species. Ion clusters are groups of m molecules tied to a positive or negative ion. For example, m water molecules can form the hydrated water cluster H + (H 2 O) m , or else other water clusters like NO 3 À (H 2 O) m or NO + (H 2 O) m . The

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Section: Monthly Mean Polar-averaged Distributions Of Ion Clustersmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Mesospheric Nitric Acid Enhancements During Energetic Electron Precipitation Events Simulated by WACCM‐D

et al. 2018

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“…For a comprehensive description of WACCM-D and its lower ionospheric performance, see Verronen et al (2016). Andersson et al (2016) showed that the addition of D region ion chemistry into WACCM significantly improves modeling of polar HNO 3 , HCl, ClO, OH, and NO x and that WACCM-D can model atmospheric effects of the January 2005 SPE (event 58 in this study, max 5,040 pfu) as compared to Aura/MLS observations. SD-WACCM-D (WACCM4) was run for the time periods of the 62 SPEs examined in this study with preconfigured specified dynamics driven by MERRA 19 × 2 (Rienecker et al, 2011) meteorological fields for the year 2000 with a 6-hr time resolution.…”

Section: Modelingmentioning

confidence: 99%

Cosmic Noise Absorption During Solar Proton Events in WACCM‐D and Riometer Observations

et al. 2019

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Solar proton events (SPEs) cause large‐scale ionization in the middle atmosphere leading to ozone loss and changes in the energy budget of the middle atmosphere. The accurate implementation of SPEs and other particle ionization sources in climate models is necessary to understand the role of energetic particle precipitation in climate variability. We use riometer observations from 16 riometer stations and the Whole Atmosphere Community Climate Model with added D region ion chemistry (WACCM‐D) to study the spatial and temporal extent of cosmic noise absorption (CNA) during 62 SPEs from 2000 to 2005. We also present a correction method for the nonlinear response of observed CNA during intense absorption events. We find that WACCM‐D can reproduce the observed CNA well with some need for future improvement and testing of the used energetic particle precipitation forcing. The average absolute difference between the model and the observations is found to be less than 0.5 dB poleward of about 66° geomagnetic latitude, and increasing with decreasing latitude to about 1 dB equatorward of about 66° geomagnetic latitude. The differences are largest during twilight conditions where the modeled changes in CNA are more abrupt compared to observations. An overestimation of about 1° to 3° geomagnetic latitude in the extent of the CNA is observed due to the fixed proton cutoff latitude in the model. An unexplained underestimation of CNA by the model during sunlit conditions is observed at stations within the polar cap during 18 of the studied events.

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“…The SIC model chemical scheme includes 70 ions, of which 41 are positive and 29 negative, and 34 neutral species with simple vertical transport (molecular and eddy diffusion). WACCM‐D (Verronen et al, ) includes a D ‐region ion scheme of 307 reactions of 20 positive ions and 21 negative ions, allowing the 3‐D global model to account for substantial HNO 3 enhancements observed in the mesosphere at altitudes ~50–80 km after major SPEs (Andersson et al, ). WACCM‐SIC (Kovács et al, ) includes a more complete set of ion‐neutral reactions from the detailed D ‐region ion chemistry in the SIC model, while ion‐ion recombination reactions are included for three major positive ions (NO + , H + (H 2 O) 3 , and H + (H 2 O) 4 ) and three major negative ions (O 2 − , CO 3 − , and NO 3 − ).…”

Section: Introductionmentioning

confidence: 99%

Observations and Modeling of Increased Nitric Oxide in the Antarctic Polar Middle Atmosphere Associated With Geomagnetic Storm‐Driven Energetic Electron Precipitation

et al. 2018

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Nitric oxide (NO) produced in the polar middle and upper atmosphere by energetic particle precipitation depletes ozone in the mesosphere and, following vertical transport in the winter polar vortex, in the stratosphere. Medium‐energy electron (MEE) ionization by 30–1,000 keV electrons during geomagnetic storms may have a significant role in mesospheric NO production. However, questions remain about the relative importance of direct NO production by MEE at altitudes ~60–90 km versus indirect NO originating from auroral ionization above 90 km. We investigate potential drivers of NO variability in the southern‐hemisphere mesosphere and lower thermosphere during 2013–2014. Contrasting geomagnetic activity occurred during the two austral winters, with more numerous moderate storms in the 2013 winter. Ground‐based millimeter‐wave observations of NO from Halley, Antarctica, are compared with measurements by the Solar Occultation For Ice Experiment (SOFIE) spaceborne spectrometer. NO partial columns over the altitude range 65–140 km from the two observational data sets show large day‐to‐day variability and significant disagreement, with Halley values on average 49% higher than the corresponding SOFIE data. SOFIE NO number densities, zonally averaged over geomagnetic latitudes −59° to −65°, are up to 3 × 108/cm3 higher in the winter of 2013 compared to 2014. Comparisons with a new version of the Whole Atmosphere Community Climate Model, which includes detailed D‐region ion chemistry (WACCM‐SIC) and MEE ionization rates, show that the model underestimates NO in the winter lower mesosphere whereas thermospheric abundances are too high. This indicates the need to further improve and verify WACCM‐SIC with respect to MEE ionization, thermospheric NO chemistry, and vertical transport.

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WACCM‐D—Improved modeling of nitric acid and active chlorine during energetic particle precipitation

Abstract: Key points.

Cited by 41 publications

References 47 publications

Mesospheric Nitric Acid Enhancements During Energetic Electron Precipitation Events Simulated by WACCM‐D

Mesospheric Nitric Acid Enhancements During Energetic Electron Precipitation Events Simulated by WACCM‐D

Cosmic Noise Absorption During Solar Proton Events in WACCM‐D and Riometer Observations

Observations and Modeling of Increased Nitric Oxide in the Antarctic Polar Middle Atmosphere Associated With Geomagnetic Storm‐Driven Energetic Electron Precipitation

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