Quantifying Denitrification and Its Effect on Ozone Recovery

Tabazadeh, A.; Santee, M. L.; Danilin, M. Y.; Pumphrey, Hugh C.; Newman, Paul A.; Hamill, Patrick; Mergenthaler, J. L.

doi:10.1126/science.288.5470.1407

Cited by 141 publications

(138 citation statements)

References 60 publications

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“…Potentially, a denitrified Arctic stratosphere in early spring is primed for ozone destruction because reactive nitrogen that can mediate ozone loss (by sequestering active chlorine) has been removed from the stratosphere. In fact, a number of studies have shown that massive denitrification in the Arctic can increase ozone loss by about 30% in a nonvolcanic stratosphere (17,18), which is in accord with the results shown in Fig. 3.…”

Section: Model Simulationssupporting

confidence: 80%

“…3 vortex-averaged denitrification fields (Insets) are shown for the winter of 1999-2000 for four cases. As shown (13,17,18), denitrification is enhanced in a colder (by 4 K) nonvolcanic atmosphere. Most of the denitrification in a nonvolcanic atmosphere is caused by sedimentation of large NAD (or NAT) particles (13).…”

Section: Model Simulationsmentioning

confidence: 95%

“…Stratospheric variations in aerosol optical depth can significantly affect heterogeneous chemistry that leads to ozone depletion because particle surface areas are directly proportional to the optical depth. Below we consider how the continuous presence of volcanic cloudy-like conditions in the Arctic can affect springtime ozone loss processes (13)(14)(15)(16)(17)(18) in a cold year such as the winter of 1999-2000.…”

Section: Volcanic Aerosol Effectsmentioning

confidence: 99%

“…We used a coupled chemistry-microphysics trajectory model (15,16) to evaluate the effects of volcanic perturbations on Arctic ozone loss processes under current and possible future colder conditions (13,17,18,21). In Fig.…”

Section: Model Simulationsmentioning

confidence: 99%

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Arctic “ozone hole” in a cold volcanic stratosphere

Tabazadeh

Drdla

Schoeberl

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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Optical depth records indicate that volcanic aerosols from major eruptions often produce clouds that have greater surface area than typical Arctic polar stratospheric clouds (PSCs). A trajectory cloudchemistry model is used to study how volcanic aerosols could affect springtime Arctic ozone loss processes, such as chlorine activation and denitrification, in a cold winter within the current range of natural variability. Several studies indicate that severe denitrification can increase Arctic ozone loss by up to 30%. We show large PSC particles that cause denitrification in a nonvolcanic stratosphere cannot efficiently form in a volcanic environment. However, volcanic aerosols, when present at low altitudes, where Arctic PSCs cannot form, can extend the vertical range of chemical ozone loss in the lower stratosphere. Chemical processing on volcanic aerosols over a 10-km altitude range could increase the current levels of springtime column ozone loss by up to 70% independent of denitrification. Climate models predict that the lower stratosphere is cooling as a result of greenhouse gas built-up in the troposphere. The magnitude of column ozone loss calculated here for the 1999 -2000 Arctic winter, in an assumed volcanic state, is similar to that projected for a colder future nonvolcanic stratosphere in the 2010 decade.E ruptions with a volcanic explosivity index (VEI) of 4 or higher produce significant stratospheric injections (1, 2). Sulfur dioxide (2), the most important atmospheric component of volcanic emissions, is converted into sulfate aerosols after injection into the stratosphere. More than 100 eruptions with VEIs Ն 4 are thought to have occurred in the past 500 years (1). However, only about half of all large eruptions are sulfur-rich (2, 3). Both the 1982 El Chichon (VEI ϭ 4) (4) and 1991 Mt. Pinatubo (VEI ϭ 5) (5) eruptions were sulfur-rich, producing volcanic clouds in the stratosphere that lasted for a number of years (6). On the other hand, the relatively sulfur-poor eruption of Mt. St. Helens (VEI ϭ 5) (2, 7) in 1980 contributed very little sulfate mass to the stratospheric aerosol layer (6). The fact that Mt. St. Helens' plume was emitted at an angle also reduced the amount of possible stratospheric injections by this volcano. Nevertheless, large sulfate-rich eruptions are common (6). Therefore, it is important to understand to what extent these eruptions could affect the Arctic ozone layer in the next 30 years or so, while anthropogenic chlorine levels are still sufficiently high [Ϸ3 parts per billion in volume (ppbv)] to cause severe ozone depletion (8, 9).Model simulations (10) have shown that the early rapid growth of the Antarctic ''ozone hole'' in the early 1980s may have been influenced (in part) by a number of large volcanic eruptions. The goal of this study is to explore how a large eruption could affect Arctic ozone loss processes, such as chlorine activation and denitrification, in a cold year within the current range of natural variability. It is projected that the Arctic climate may be ...

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Section: Model Simulationssupporting

confidence: 80%

Section: Model Simulationsmentioning

confidence: 95%

Section: Volcanic Aerosol Effectsmentioning

confidence: 99%

Section: Model Simulationsmentioning

confidence: 99%

See 2 more Smart Citations

Arctic “ozone hole” in a cold volcanic stratosphere

Tabazadeh

Drdla

Schoeberl

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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“…Several CTM studies have shown that denitrification in mid-winter can increase springtime Arctic ozone loss by reducing HNO 3 concentrations in the lower stratosphere, thus reducing the rate of ClO x deactivation and extending the ozone loss period (e.g. Chipperfield and Pyle, 1998;Waibel et al, 1999;Tabazadeh et al, 2000;.…”

Section: Introductionmentioning

confidence: 99%

Testing our understanding of Arctic denitrification using MIPAS-E satellite measurements in winter 2002/2003

et al. 2006

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Abstract. Observations of gas-phase HNO 3 and N 2 O in the polar stratosphere from the Michelson Interferometer for Passive Atmospheric Sounding aboard the ENVISAT satellite (MIPAS-E) were made during the cold Arctic winter of 2002/2003. Vortex temperatures were unusually low in early winter and remained favourable for polar stratospheric cloud formation and denitrification until mid-January. MIPAS-E observations provide the first dataset with sufficient coverage of the polar vortex in mid-winter which enables a reasonable estimate of the timing of onset and spatial distribution of denitrification of the Arctic lower stratosphere to be performed. We use the observations from MIPAS-E to test the evolution of denitrification in the DLAPSE (Denitrification by Lagrangian Particle Sedimentation) microphysical denitrification model coupled to the SLIMCAT chemical transport model. In addition, the predicted denitrification from a simple equilibrium nitric acid trihydrate-based scheme is also compared with MIPAS-E. Modelled denitrification is compared with in-vortex NO y and N 2 O observations from the balloon-borne MarkIV interferometer in mid-December. Denitrification was clearly observed by MIPAS-E in midDecember 2002 and reached 80% in the core of the vortex by early January 2003. The DLAPSE model is broadly able to capture both the timing of onset and the spatial distribution of the observed denitrification. A simple thermodynamic equilibrium scheme is able to reproduce the observed denitrification in the core of the vortex but overestimates denitrification closer to the vortex edge. This study also suggests that the onset of denitrification in simple thermodynamic schemes may be earlier than in the MIPAS-E observations.

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Environmental UV Radiation: Impact on Ecosystems and Human Health and Predictive Models

Ghetti¹,

Checcucci²,

Bornman³

2006

Nato Science Series: IV: Earth and Environmental Sciences

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Sub-Series I. Life and Behavioural Sciences IOS Press II. Mathematics, Physics and Chemistry III. Computer and Systems Science IOS Press IV. Earth and Environmental Sciences Advanced Study Institutes are high-level tutorial courses offering in-depth study of latest advances in a field. Advanced Research Workshops are expert meetings aimed at critical assessment of a field, and identification of directions for future action.As a consequence of the restructuring of the NATO Science Programme in 1999, the NATO Science Series was re-organized to the four sub-series noted above. Please consult the following web sites for information on previous volumes published in the Series.

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Quantifying Denitrification and Its Effect on Ozone Recovery

Cited by 141 publications

References 60 publications

Arctic “ozone hole” in a cold volcanic stratosphere

Arctic “ozone hole” in a cold volcanic stratosphere

Testing our understanding of Arctic denitrification using MIPAS-E satellite measurements in winter 2002/2003

Environmental UV Radiation: Impact on Ecosystems and Human Health and Predictive Models

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