Chemical ozone loss in the Arctic winter 1991–1992

Tilmes, Simone; Müller, Rolf; Salawitch, R. J.; Schmidt, Ulrich; Webster, Christopher R.; Oelhaf, H.; Camy‐Peyret, C.; Russell, James M.

doi:10.5194/acp-8-1897-2008

Cited by 25 publications

(21 citation statements)

References 51 publications

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“…The influence of the sulfate aerosol on stratospheric ozone was particularly observable after the eruptions of El Chichón (Hofmann and Solomon, 1989) and Mt. Pinatubo (Portmann et al, 1996;Tilmes et al, 2008b).…”

mentioning

confidence: 94%

Heterogeneous chlorine activation on stratospheric aerosols and clouds in the Arctic polar vortex

Wegner¹,

Grooß²,

Hobe³

et al. 2012

Atmos. Chem. Phys.

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Abstract. Chlorine activation in the Arctic is investigated by examining different parameterizations for uptake coefficients on stratospheric aerosols, high-resolution in-situ measurements and vortex-wide satellite observations. The parameterizations for heterogeneous chemistry on liquid aerosols are most sensitive to temperature with the reaction rates doubling for every 1 K increase in temperature. However, differences between the currently available parameterizations are negligible. For Nitric Acid Trihydrate particles (NAT) the major factors of uncertainty are the number density of nucleated particles and different parameterizations for heterogeneous chemistry. These two factors induce an uncertainty that covers several orders of magnitude on the reaction rate. Nonetheless, since predicted reaction rates on liquid aerosols always exceed those on NAT, the overall uncertainty for chlorine activation is small. In-situ observations of ClO x from Arctic winters in 2005 and 2010 are used to evaluate the heterogeneous chemistry parameterizations. The conditions for these measurements proved to be very different between those two winters with HCl being the limiting reacting partner for the 2005 measurements and ClONO 2 for the 2010 measurements. Modeled levels of chlorine activation are in very good agreement with the in-situ observations and the surface area provided by Polar Stratospheric Clouds (PSCs) has only a limited impact on modeled chlorine activation. This indicates that the parameterizations give a good representation of the processes in the atmosphere. Back-trajectories started on the location of the observations in 2005 indicate temperatures on the threshold for PSC formation, hence the surface area is mainly provided by the background aerosol. Still, the model shows additional chlorine activation during this time-frame, providing cautionary evidence for chlorine activation even in the absence of PSCs. Vortex-averaged satellite observations by the MLS instrument also show no definite connection between chlorine activation and PSC formation. The inter -and intra-annual variability of vortex-average HCl and HNO 3 based on MLS observations is examined for the Arctic winters 2004/2005 to 2010/2011. These observations show that removal of HCl and HNO 3 from the gas-phase are not correlated. HNO 3 loss exhibits great inter-annual variability depending on prevailing temperatures while HCl loss is continuous through December without considerable inter-or intra-annual variability. Only the recovery of HCl in late winter depends on the level of denitrification. Hence, the occurrence of HNO 3 containing PSC particles does not seem to have a significant effect on the speed of initial chlorine activation on a vortex-wide scale.

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mentioning

confidence: 94%

Heterogeneous chlorine activation on stratospheric aerosols and clouds in the Arctic polar vortex

Wegner¹,

Grooß²,

Hobe³

et al. 2012

Atmos. Chem. Phys.

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“…The June 1991 eruption of Mount Pinatubo was a large-magnitude eruption, with a volcanic explosivity index (VEI, as defined in Newhall and Self, 1982) of 6, that had a significant impact on the stratospheric aerosol layer and hence climate (Bluth et al, 1992;Sato et al, 1993;Ammann et al, 2003): global aerosol optical depth (AOD) (in the visible) was enhanced, reaching up to 0.15, causing a surface cooling of up to 0.5 • C (Douglass and Knox, 2005;Wunderlich and Mitchell, 2017). In addition, stratospheric halogens (bromine and chlorine, which are present at elevated post-industrial concentrations in the stratosphere as a consequence of past anthropogenic chlorofluorocarbon (CFC) emissions) became activated through reactions on the volcanic aerosol, causing substantial depletion of stratospheric ozone and larger polar ozone holes Solomon et al, 1996;Tilmes et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Here, we present model simulations of stratospheric aerosol evolution and chemistry following the moderatemagnitude 2009 Sarychev eruption using the global Community Earth System Model version 1.0 (CESM1) (Marsh et al, 2013), with its Whole Atmosphere Community Climate Model (WACCM) module for the simulation of the atmosphere, along with the sectional Community Aerosol and Radiation Model for Atmospheres module (CARMA; Toon et al, 1988) to simulate aerosol microphysics. The sectional scheme distributes particles according to their size over 30 size bins, enabling the evolution of the particle size distribution to be traced in detail with no a priori assumptions on particle size.…”

Section: Introductionmentioning

confidence: 99%

Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations

Lurton

Jégou²,

Berthet³

et al. 2018

Atmos. Chem. Phys.

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Abstract. Volcanic eruptions impact climate through the injection of sulfur dioxide (SO2), which is oxidized to form sulfuric acid aerosol particles that can enhance the stratospheric aerosol optical depth (SAOD). Besides large-magnitude eruptions, moderate-magnitude eruptions such as Kasatochi in 2008 and Sarychev Peak in 2009 can have a significant impact on stratospheric aerosol and hence climate. However, uncertainties remain in quantifying the atmospheric and climatic impacts of the 2009 Sarychev Peak eruption due to limitations in previous model representations of volcanic aerosol microphysics and particle size, whilst biases have been identified in satellite estimates of post-eruption SAOD. In addition, the 2009 Sarychev Peak eruption co-injected hydrogen chloride (HCl) alongside SO2, whose potential stratospheric chemistry impacts have not been investigated to date. We present a study of the stratospheric SO2–particle–HCl processing and impacts following Sarychev Peak eruption, using the Community Earth System Model version 1.0 (CESM1) Whole Atmosphere Community Climate Model (WACCM) – Community Aerosol and Radiation Model for Atmospheres (CARMA) sectional aerosol microphysics model (with no a priori assumption on particle size). The Sarychev Peak 2009 eruption injected 0.9 Tg of SO2 into the upper troposphere and lower stratosphere (UTLS), enhancing the aerosol load in the Northern Hemisphere. The post-eruption evolution of the volcanic SO2 in space and time are well reproduced by the model when compared to Infrared Atmospheric Sounding Interferometer (IASI) satellite data. Co-injection of 27 Gg HCl causes a lengthening of the SO2 lifetime and a slight delay in the formation of aerosols, and acts to enhance the destruction of stratospheric ozone and mono-nitrogen oxides (NOx) compared to the simulation with volcanic SO2 only. We therefore highlight the need to account for volcanic halogen chemistry when simulating the impact of eruptions such as Sarychev on stratospheric chemistry. The model-simulated evolution of effective radius (reff) reflects new particle formation followed by particle growth that enhances reff to reach up to 0.2 µm on zonal average. Comparisons of the model-simulated particle number and size distributions to balloon-borne in situ stratospheric observations over Kiruna, Sweden, in August and September 2009, and over Laramie, USA, in June and November 2009 show good agreement and quantitatively confirm the post-eruption particle enhancement. We show that the model-simulated SAOD is consistent with that derived from the Optical Spectrograph and InfraRed Imager System (OSIRIS) when both the saturation bias of OSIRIS and the fact that extinction profiles may terminate well above the tropopause are taken into account. Previous modelling studies (involving assumptions on particle size) that reported agreement with (biased) post-eruption estimates of SAOD derived from OSIRIS likely underestimated the climate impact of the 2009 Sarychev Peak eruption.

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“…5). Large volcanic eruptions can increase stratospheric aerosol surface areas, causing enhanced chlorine activation (Toon et al, 1993) and ozone loss (e.g., Hofmann and Solomon, 1989;Hofmann and Oltmans, 1993;Portmann et al, 1996;Deshler et al, 1996;Tabazadeh et al, 2002;Rex et al, 2004;Solomon et al, 2005;Tilmes et al, 2008b). Portmann et al (1996) investigated the interannual variability of Antarctic ozone loss and emphasised the Fig.…”

Section: The Chlorine Activation Threshold: T Aclmentioning

confidence: 99%

Temperature thresholds for chlorine activation and ozone loss in the polar stratosphere

Drdla

Müller²

2012

Ann. Geophys.

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122

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Abstract. Low stratospheric temperatures are known to be responsible for heterogeneous chlorine activation that leads to polar ozone depletion. Here, we discuss the temperature threshold below which substantial chlorine activation occurs. We suggest that the onset of chlorine activation is dominated by reactions on cold binary aerosol particles, without the formation of polar stratospheric clouds (PSCs), i.e. without any significant uptake of HNO 3 from the gas phase. Using reaction rates on cold binary aerosol in a model of stratospheric chemistry, a chlorine activation threshold temperature, T ACL , is derived. At typical stratospheric conditions, T ACL is similar in value to T NAT (within 1-2 K), the highest temperature at which nitric acid trihydrate (NAT) can exist. T NAT is still in use to parameterise the threshold temperature for the onset of chlorine activation. However, perturbations can cause T ACL to differ from T NAT : T ACL is dependent upon H 2 O and potential temperature, but unlike T NAT is not dependent upon HNO 3 . Furthermore, in contrast to T NAT , T ACL is dependent upon the stratospheric sulfate aerosol loading and thus provides a means to estimate the impact on polar ozone of strong volcanic eruptions and some geo-engineering options, which are discussed. A parameterisation of T ACL is provided here, allowing it to be calculated for low solar elevation (or high solar zenith angle) over a comprehensive range of stratospheric conditions. Considering T ACL as a proxy for chlorine activation cannot replace a detailed model calculation, and polar ozone loss is influenced by other factors apart from the initial chlorine activation. However, T ACL provides a more accurate description of the temperature conditions necessary for chlorine activation and ozone loss in the polar stratosphere than T NAT .

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Chemical ozone loss in the Arctic winter 1991–1992

Cited by 25 publications

References 51 publications

Heterogeneous chlorine activation on stratospheric aerosols and clouds in the Arctic polar vortex

Heterogeneous chlorine activation on stratospheric aerosols and clouds in the Arctic polar vortex

Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations

Temperature thresholds for chlorine activation and ozone loss in the polar stratosphere

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