How different would tropospheric oxidation be over an ice‐free Arctic?

Voulgarakis, Apostolos; Yang, Xin; Pyle, J. A.

doi:10.1029/2009gl040541

Cited by 16 publications

(19 citation statements)

References 29 publications

(30 reference statements)

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“…A recent calculation demonstrates that the sea salt produced in association with blowing snow events could be a significant bromine source (Yang et al, 2008), which is consistent with recent insitu measurements of higher bromide levels in blowing snow in coastal Antarctica (Jones et al, 2009). Inclusion of this source in the Arctic has a significant effect on tropospheric BrO and oxidation (through ozone and OH) (Voulgarakis et al, 2009).…”

Section: Introductionsupporting

confidence: 67%

Snow-sourced bromine and its implications for polar tropospheric ozone

et al. 2010

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Abstract. In the last two decades, significant depletion of boundary layer ozone (ozone depletion events, ODEs) has been observed in both Arctic and Antarctic spring. ODEs are attributed to catalytic destruction by bromine radicals (Br plus BrO), especially during bromine explosion events (BEs), when high concentrations of BrO periodically occur. However, neither the exact source of bromine nor the mechanism for sustaining the observed high BrO concentrations is completely understood. Here, by considering the production of sea salt aerosol from snow lying on sea ice during blowing snow events and the subsequent release of bromine, we successfully simulate the BEs using a global chemistry transport model. We find that heterogeneous reactions play an important role in sustaining a high fraction of the total inorganic bromine as BrO. We also find that emissions of bromine associated with blowing snow contribute significantly to BrO at mid-latitudes. Modeled tropospheric BrO columns generally compare well with the tropospheric BrO columns retrieved from the GOME satellite instrument (Global Ozone Monitoring Experiment). The additional blowing snow bromine source, identified here, reduces modeled high latitude lower tropospheric ozone amounts by up to an average 8% in polar spring.

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Section: Introductionsupporting

confidence: 67%

Snow-sourced bromine and its implications for polar tropospheric ozone

et al. 2010

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“…Ozone recovery in the three simulations assuming reduced halogen (ORLM, ORHM, ORCC) does indeed result in generally decreased rates of photolysis of ozone in the O 3 + hv → O( 1 D) channel by roughly 1% in summer, but those changes are mostly insignificant for the 10 year runs considered here (Figure ). Significant decreases of approximately 10% occur in the near‐surface O 3 → O( 1 D) photolysis rate during summer over sea in the Arctic and Antarctic (in the CC and ORCC simulations); these are due to a reduction of sea ice cover in these runs under climate change (of about 2/3 in August), which causes the surface albedo to decrease [ Voulgarakis et al ., ]. Note that in the model, sea ice albedo is in the range of 0.57–0.8, depending on snow cover.…”

Section: Sensitivity To Climate Change Ozone Recovery and Increasinmentioning

confidence: 99%

Impacts of climate change, ozone recovery, and increasing methane on surface ozone and the tropospheric oxidizing capacity

et al. 2013

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[1] Using a stratosphere-troposphere chemistry-climate model, we compare the impacts of climate change, stratospheric ozone recovery, and methane increases on surface ozone and the tropospheric oxidizing capacity by 2050. Methane increases lead to a decreasing OH, particularly in the northern subtropics during summer. Stratospheric ozone recovery causes small increases of surface OH driven by increased stratosphere-troposphere exchange, occurring during parts of the year in the southern extratropics. Tropospheric warming is also associated with increasing OH, maximizing in the Northern Hemisphere in northern summer. In combination, OH is anticipated to decrease by approximately 8% in the tropospheric average by 2050 in the scenario considered here. In conjunction with these changes to OH, we model substantial changes in surface ozone in both hemispheres. Methane increases alone will lead to increasing surface ozone by up to 2-3 ppbv in the zonal mean, maximizing around 30 N. This increase is exacerbated during austral winter when increased stratosphere-troposphere flux of ozone causes an increase in surface ozone in the southern extratropics. Both increases are partially offset by decreases in surface ozone of up to 2 ppbv in the zonal mean, with substantial zonal asymmetries, due to global warming. We model substantial changes in the methane lifetime caused by the three factors. In the Arctic during summer, disappearing sea ice, in an ice-albedo feedback, causes substantially reduced surface ozone. Of the three factors considered here, methane increases are found to exert the strongest influence on surface ozone.

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“…A reduction in Arctic sea ice would reduce the importance of this process in the chemistry of the Arctic atmosphere. In chemistry model simulations, Voulgarakis et al (2009) found large spring ozone increases (up to 50-60%) over the Arctic, due mainly to a reduction in the impact of bromine chemistry, caused by sea-ice retreat. Tropospheric ozone has a relatively small radiative impact (warming), although the effect is greater over bright surfaces (Shindell et al 2006).…”

Section: Ozone and Bromine (Marine)mentioning

confidence: 99%

Feedbacks and Interactions: From the Arctic Cryosphere to the Climate System

Callaghan

Johansson

Key

et al. 2011

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Changes in the Arctic's climate are a result of complex interactions between the cryosphere, atmosphere, ocean, and biosphere. More feedbacks from the cryosphere to climate warming are positive and result in further warming than are negative, resulting in a reduced rate of warming or cooling. Feedbacks operate at different spatial scales; many, such as those operating through albedo and evapotranspiration, will have significant local effects that together could result in global impacts. Some processes, such as changes in carbon dioxide (CO 2 ) emissions, are likely to have very small global effects but uncertainty is high whereas others, such as subsea methane (CH 4 ) emissions, could have large global effects. Some cryospheric processes in the Arctic have teleconnections with other regions and major changes in the cryosphere have been largely a result of large-scale processes, particularly atmospheric and oceanic circulation. With continued climate warming it is highly likely that the cryospheric components will play an increasingly important climatic role. However, the net effect of all the feedbacks is difficult to assess because of the variability in spatial and temporal scales over which they operate. Furthermore, general circulation models (GCMs) do not include all major feedbacks while those included may not be accurately parameterized. The lack of full coupling between surface dynamics and the atmosphere is a major gap in current GCMs.

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How different would tropospheric oxidation be over an ice‐free Arctic?

Cited by 16 publications

References 29 publications

Snow-sourced bromine and its implications for polar tropospheric ozone

Snow-sourced bromine and its implications for polar tropospheric ozone

Impacts of climate change, ozone recovery, and increasing methane on surface ozone and the tropospheric oxidizing capacity

Feedbacks and Interactions: From the Arctic Cryosphere to the Climate System

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