Response of middle atmosphere chemistry and dynamics to volcanically elevated sulfate aerosol: Three‐dimensional coupled model simulations

Al-Saadi, J. A.; Pierce, R. Bradley; Fairlie, T. D.; Kleb, M. M.; Eckman, Richard S.; Grose, W. L.; Natarajan, M.; Olson, J. R.

doi:10.1029/2000jd000185

Cited by 22 publications

(40 citation statements)

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“…Quantifying the impact of volcanic aerosols on stratospheric ozone chemistry is difficult as chemical and dynamical (radiative) effects occur simultaneously (Pitari and Rizi, 1993;Robock, 2000;Al-Saadi et al, 2001;Aquila et al, 2013). The model is a CTM driven by ECMWF offline meteorological data and does not describe radiative processes.…”

Section: Discussionmentioning

confidence: 99%

“…We have also excluded dynamical and radiative effects on the ozone response, which have been shown to be of primary importance when dense volcanic clouds are present (e.g. Pitari and Rizi, 1993;Tie et al, 1994;Al-Saadi et al, 2001). In a forthcoming study it would be interesting to compare dynamical or radiative and chemical effects of moderate volcanic eruptions on stratospheric ozone using chemistry-climate models with full sulfur chemistry and aerosol-dynamics interactive calculations.…”

Section: Discussionmentioning

confidence: 99%

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Impact of a moderate volcanic eruption on chemistry in the lower stratosphere: balloon-borne observations and model calculations

et al. 2017

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Abstract. The major volcanic eruption of Mount Pinatubo in 1991 has been shown to have significant effects on stratospheric chemistry and ozone depletion even at midlatitudes. Since then, only "moderate" but recurrent volcanic eruptions have modulated the stratospheric aerosol loading and are assumed to be one cause for the reported increase in the global aerosol content over the past 15 years. This particularly enhanced aerosol context raises questions about the effects on stratospheric chemistry which depend on the latitude, altitude and season of injection. In this study, we focus on the midlatitude Sarychev volcano eruption in June 2009, which injected 0.9 Tg of sulfur dioxide (about 20 times less than Pinatubo) into a lower stratosphere mainly governed by high-stratospheric temperatures. Together with in situ measurements of aerosol amounts, we analyse high-resolution in situ and/or remote-sensing observations of NO 2 , HNO 3 and BrO from balloon-borne infrared and UV-visible spectrometers launched in Sweden in August-September 2009. It is shown that differences between observations and threedimensional (3-D) chemistry-transport model (CTM) outputs are not due to transport calculation issues but rather reflect the chemical impact of the volcanic plume below 19 km altitude. Good measurement-model agreement is obtained when the CTM is driven by volcanic aerosol loadings derived from in situ or space-borne data. As a result of enhanced N 2 O 5 hydrolysis in the Sarychev volcanic aerosol conditions, the model calculates reductions of ∼ 45 % and increases of ∼ 11 % in NO 2 and HNO 3 amounts respectively over the August-September 2009 period. The decrease in NO x abundances is limited due to the expected saturation effect for high aerosol loadings. The links between the various chemical catalytic cycles involving chlorine, bromine, nitrogen and HO x compounds in the lower stratosphere are discussed. The increased BrO amounts (∼ 22 %) compare rather well with the balloon-borne observations when volcanic aerosol levels are accounted for in the CTM and appear to be mainly controlled by the coupling with nitrogen chemistry rather than by enhanced BrONO 2 hydrolysis. We show Published by Copernicus Publications on behalf of the European Geosciences Union. 2230G. Berthet et al.: Impact of a moderate volcanic eruption on chemistry in the lower stratosphere that the chlorine partitioning is significantly controlled by enhanced BrONO 2 hydrolysis. However, simulated effects of the Sarychev eruption on chlorine activation are very limited in the high-temperature conditions in the stratosphere in the period considered, inhibiting the effect of ClONO 2 hydrolysis. As a consequence, the simulated chemical ozone loss due to the Sarychev aerosols is low with a reduction of −22 ppbv (−1.5 %) of the ozone budget around 16 km. This is at least 10 times lower than the maximum ozone depletion from chemical processes (up to −20 %) reported in the Northern Hemisphere lower stratosphere over the first year following the Pinatubo erupti...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Impact of a moderate volcanic eruption on chemistry in the lower stratosphere: balloon-borne observations and model calculations

et al. 2017

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“…A number of investigators have wondered to what extent the eruption of Mt. Pinatubo may have affected the SC‐like and trend terms for ozone [e.g., Lee and Smith , 2003; Al‐Saadi et al , 2001]. Furthermore, Crooks and Gray [2005] point out that there were interactions between the QBO and ENSO that were altering the zonal winds of the subtropical middle stratosphere both prior to and just following the eruption of Mt.…”

Section: Trends In Haloe Ozonementioning

confidence: 99%

On the response of Halogen Occultation Experiment (HALOE) stratospheric ozone and temperature to the 11‐year solar cycle forcing

Remsberg¹

2008

J. Geophys. Res.

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[1] Results are presented on responses in 14-year (1991-2005) time series of stratospheric ozone and temperature from the Halogen Occultation Experiment (HALOE) of the Upper Atmosphere Research Satellite (UARS) to a solar cycle (SC-like) variation. The ozone time series are for ten, 20-degree-wide, latitude bins from 45°S to 45°N and for thirteen ''half-Umkehr'' layers of about 2.5 km thickness and extending from 63 hPa to 0.7 hPa. The temperature time series analyses were restricted to pressure levels in the range of 2 hPa to 0.7 hPa. Multiple linear regression (MLR) techniques were applied to each of the 130 time series of bin-averaged, sunrise plus sunset ozone points over that latitude/pressure domain. A simple, 11-year periodic term and a linear trend term were added to the final MLR models after their seasonal and interannual terms had been determined. Where the amplitudes of the 11-year terms are significant, they are in phase with those of the more standard proxies for the solar UV flux. The maximum minus minimum response for ozone is on the order of 2 to 3% from about 2 to 5 hPa and for the latitudes of 45°S to 45°N. There is also a significant maximum minus minimum response on the order of 1 K for temperature between 15°S and 15°N and from 2 to 0.7 hPa. The associated linear trends for ozone are near zero in the upper stratosphere. It is noted, however, that effects of the changes in total chlorine during this 14-year period were not accounted for explicitly and that their omission can be a confounding effect for both the analyzed solar cycle responses and the linear terms, especially for tropical upper stratospheric ozone. It is concluded that the solar occultation technique of HALOE provided adequate sampling and sufficient vertical resolution for obtaining the solar cycle response in stratospheric ozone.

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“…The chemical module of the LaRC LCTM is from the NASA Langley Interactive Modeling project for Atmospheric Chemistry and Transport (IMPACT) model [ Al‐Saadi et al , 2002; Pierce et al , 2000; Eckman et al , 1995], which is a coupled 3D chemical‐dynamical model of the troposphere and stratosphere. The implementation of the chemical module in the LaRC LCTM is described by Pierce et al [1999] and recent developments are described here.…”

Section: The Larc Lagrangian Chemical Transport Model (Larc Lctm)mentioning

confidence: 99%

Large‐scale chemical evolution of the Arctic vortex during the 1999/2000 winter: HALOE/POAM III Lagrangian photochemical modeling for the SAGE III—Ozone Loss and Validation Experiment (SOLVE) campaign

et al. 2002

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[1] The LaRC Lagrangian Chemical Transport Model (LaRC LCTM) is used to simulate the kinematic and chemical evolution of an ensemble of trajectories initialized from Halogen Occultation Experiment (HALOE) and Polar Ozone and Aerosol Measurement (POAM) III atmospheric soundings over the SAGE III-Ozone Loss and Validation Experiment (SOLVE) campaign period. Initial mixing ratios of species which are not measured by HALOE or POAM III are specified using sunrise and sunset constituent CH 4 and constituent PV regressions obtained from the LaRC IMPACT model, a global three dimensional general circulation and photochemical model. Ensemble averaging of the trajectory chemical characteristics provides a vortex-average perspective of the photochemical state of the Arctic vortex. The vortex-averaged evolution of ozone, chlorine, nitrogen species, and ozone photochemical loss rates is presented. Enhanced chlorine catalyzed ozone loss begins in mid-January above 500 K, and the altitude of the peak loss gradually descends during the rest of the simulation. Peak vortex averaged loss rates of over 60 ppbv/day occur in early March at 450 K. Vortex averaged loss rates decline after midMarch. The accumulated photochemical ozone loss during the period from 1 December 1999 to 30 March 2000 peaks at 450 K with net losses of near 2.2 ppmv. The predicted distributions of CH 4 , O 3 , denitrification, and chlorine activation are compared to the distributions obtained from in situ measurements to evaluate the accuracy of the simulations. The comparisons show best agreement when diffusive tendencies are included in the model calculations, highlighting the importance of this process in the Arctic vortex. Sensitivity tests examining the large-scale influence of orographically generated gravitywave temperature anomalies are also presented. Results from this sensitivity study show that mountain-wave temperature perturbations contribute an additional 2-8% O 3 loss during the 1999/2000 winter.

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Response of middle atmosphere chemistry and dynamics to volcanically elevated sulfate aerosol: Three‐dimensional coupled model simulations

Cited by 22 publications

References 54 publications

Impact of a moderate volcanic eruption on chemistry in the lower stratosphere: balloon-borne observations and model calculations

Impact of a moderate volcanic eruption on chemistry in the lower stratosphere: balloon-borne observations and model calculations

On the response of Halogen Occultation Experiment (HALOE) stratospheric ozone and temperature to the 11‐year solar cycle forcing

Large‐scale chemical evolution of the Arctic vortex during the 1999/2000 winter: HALOE/POAM III Lagrangian photochemical modeling for the SAGE III—Ozone Loss and Validation Experiment (SOLVE) campaign

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