Nitric Oxide Response to the April 2010 Electron Precipitation Event: Using WACCM and WACCM‐D With and Without Medium‐Energy Electrons

Smith‐Johnsen, Christine; Marsh, Daniel R.; Orsolini, Yvan; Tyssøy, Hilde Nesse; Hendrickx, Koen; Sandanger, Marit Irene; Ødegaard, Linn-Kristine Glesnes; Stordal, Frøde

doi:10.1029/2018ja025418

Cited by 36 publications

(46 citation statements)

References 39 publications

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“…That even the baseline simulation shows a high bias would argue that too much auroral EEP and/or too-rapid descent in the MLT also contributes to the bias. An overestimate of auroral EEP is consistent with the WACCM results for the northern hemisphere winter of 2004 reported by Randall et al (2015), but inconsistent with the WACCM simulations of a geomagnetic storm in April 2010 reported by Smith-Johnsen et al (2018). The possibility that the bias is caused by too-rapid (or prolonged) descent is revisited below in the discussion of Figure 8.…”

Section: Journal Of Geophysical Research: Space Physicsmentioning

confidence: 66%

“…Water cluster chemistry can have a significant impact on odd nitrogen in the mesosphere, but is not included in the default model . As shown by Newnham et al (2018) and Smith-Johnsen et al (2018), SD-WACCM-D describes the mesosphere and lower thermosphere chemistry during geomagnetically active times more accurately than regular WACCM. For simplicity, for the remainder of the paper we refer to the model used as WACCM, but it should be understood that this is the specified dynamics version of WACCM4 with D-region chemistry.…”

Section: Numerical Simulations and Observationsmentioning

confidence: 94%

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Atmospheric Effects of >30‐keV Energetic Electron Precipitation in the Southern Hemisphere Winter During 2003

Pettit

Randall

Peck³

et al. 2019

JGR Space Physics

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The atmospheric effects of precipitating electrons are not fully understood, and uncertainties are large for electrons with energies greater than ~30 keV. These electrons are underrepresented in modeling studies today, primarily because valid measurements of their precipitating spectral energy fluxes are lacking. This paper compares simulations from the Whole Atmosphere Community Climate Model (WACCM) that incorporated two different estimates of precipitating electron fluxes for electrons with energies greater than 30 keV. The estimates are both based on data from the Polar Orbiting Environmental Satellite Medium Energy Proton and Electron Detector (MEPED) instruments but differ in several significant ways. Most importantly, only one of the estimates includes both the 0° and 90° telescopes from the MEPED instrument. Comparisons are presented between the WACCM results and satellite observations poleward of 30°S during the austral winter of 2003, a period of significant energetic electron precipitation. Both of the model simulations forced with precipitating electrons with energies >30 keV match the observed descent of reactive odd nitrogen better than a baseline simulation that included auroral electrons, but no higher energy electrons. However, the simulation that included both telescopes shows substantially better agreement with observations, particularly at midlatitudes. The results indicate that including energies >30 keV and the full range of pitch angles to calculate precipitating electron fluxes is necessary for improving simulations of the atmospheric effects of energetic electron precipitation.

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Section: Journal Of Geophysical Research: Space Physicsmentioning

confidence: 66%

Section: Numerical Simulations and Observationsmentioning

confidence: 94%

Atmospheric Effects of >30‐keV Energetic Electron Precipitation in the Southern Hemisphere Winter During 2003

Pettit

Randall

Peck³

et al. 2019

JGR Space Physics

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“…High-top models notoriously underestimate this effect, the cause being insufficient vertical transport and/or missing medium-energy electrons (e.g., Funke et al, 2017;Holt et al, 2013;Orsolini et al, 2017;Randall et al, 2015). Smith-Johnsen et al (2018) showed better agreement with observations when D region chemistry was added to the Whole Atmosphere Community Climate Model (WACCM) but the NO underestimate persisted between 90 and 110 km. Recent studies have shown that either constraining the model up to 90 km or assimilating mesospheric data improves the representation of the EPP IE Sassi et al, 2018;Siskind et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Mesospheric Polar Vortices in WACCM

et al. 2019

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This work evaluates the wintertime mesospheric polar vortices in the Whole Atmosphere Community Climate Model. Mesospheric altitudes are where high‐top models underestimate the concentration of nitrogen oxides produced by energetic particle precipitation. For this reason, we seek to determine the extent to which the observed mesospheric vortex size and frequency of occurrence is reproduced by the model. We compare 13 years (2005–2017) of “specified dynamics” Whole Atmosphere Community Climate Model (where meteorology in the troposphere and stratosphere is constrained by observations) to Sounding of the Atmosphere using Broadband Emission Radiometry and Mesospheric Limb Sounder observations. Near 75 km, the model reproduces observed winter mesospheric vortex frequency of occurrence rates and size reasonably well. The simulated Antarctic mesospheric vortex is displaced toward the Pacific longitude sector, and the Arctic mesospheric vortex is present 10–20% less often over the pole but ~5% more often in midlatitudes, particularly over the continents. These differences are attributed to larger planetary waves in the model. There are significant differences between the modeled and observed mean polar winter circulation near 90 km. Model‐measurement differences suggest that the simulated Antarctic mesospheric vortex does not extend to high enough altitudes, and the Arctic mesospheric vortex is too displaced from the pole. Despite these differences, the model accurately captures the evolution of structural changes to the mesospheric vortex following prolonged sudden stratospheric warmings. Thus, we conclude that model underestimates of nitrogen oxides produced by energetic particle precipitation after these warmings are not due to a misrepresentation of the mesospheric vortex strength and size below 80 km.

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“…This layer in WACCM is placed at a higher altitude throughout almost the entire year, with a six kilometre difference as compared to SOFIE during winter. Auroral electron precipitation in WACCM has a characteristic energy of 2 keV, corresponding to a maximum energy deposition at an altitude of 110 km, but increasing this characteristic energy does not sufficiently lower the NO peak layer (Smith-Johnsen et al, 2017a).…”

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confidence: 99%

Production and transport mechanisms of NO in observations and models

Hendrickx

Megner

Marsh

et al. 2018

Preprint

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Abstract. A reservoir of Nitric Oxide (NO) in the lower thermosphere efficiently cools the atmosphere after periods of enhanced geomagnetic activity. Transport from this reservoir to the stratosphere within the winter polar vortex allows NO to deplete ozone levels and thereby affect the middle atmospheric heat budget. As more climate models resolve the mesosphere and lower thermosphere (MLT) region, the need for an improved representation of NO related processes increases. This work presents a detailed comparison of NO in the Antarctic MLT region between observations made by the Solar Occultation for Ice 5 Experiment (SOFIE) instrument onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite and simulations performed by the Whole Atmosphere Community Climate Model with Specified Dynamics (SD-WACCM). We investigate 7 years of SOFIE observations and focus on the Southern hemisphere, rather than on dynamical variability in the Northern hemisphere or a specific geomagnetic perturbed event. The morphology of the simulated NO is in agreement with observations though the long term mean is too high and the short term variability is too low. Number densities are more similar during winter, though 10 the altitude of peak densities, which reaches between 102 -106 km in WACCM and between 98-104 km in SOFIE, is most separated during winter. Using multiple linear regressions and superposed epoch analyses we investigate how well the NO production and transport are represented in the model. The impact of geomagnetic activity is shown to drive NO variations in the lower thermosphere similarly across both datasets. The dynamical transport from the lower thermosphere into the mesosphere during polar winter is found to agree very well, with a descent rate of about 2.2 km/day in the 80 -110 km region in 15 both datasets. The downward transported NO fluxes are however too low in WACCM, which is likely due to medium energy electrons and D-region chemistry that are not represented in the model.

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Nitric Oxide Response to the April 2010 Electron Precipitation Event: Using WACCM and WACCM‐D With and Without Medium‐Energy Electrons

Cited by 36 publications

References 39 publications

Atmospheric Effects of >30‐keV Energetic Electron Precipitation in the Southern Hemisphere Winter During 2003

Atmospheric Effects of >30‐keV Energetic Electron Precipitation in the Southern Hemisphere Winter During 2003

Evaluation of the Mesospheric Polar Vortices in WACCM

Production and transport mechanisms of NO in observations and models

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