Technical Note: SWIFT – a fast semi-empirical model for polar stratospheric ozone loss

Abstract. An extremely fast model to estimate the degree of stratospheric ozone depletion during polar winters is described. It is based on a set of coupled differential equations that simulate the seasonal evolution of vortex-averaged hydrogen chloride (HCl), nitric acid (HNO3), chlorine nitrate (ClONO2), active forms of chlorine (ClOx = Cl + ClO + 2 ClOOCl) and ozone (O3) on isentropic levels within the polar vortices. Terms in these equations account for the chemical and physical processes driving the time rate of change of these species. Eight empirical fit coefficients associated with these terms are derived by iteratively fitting the equations to vortex-averaged satellite-based measurements of HCl, HNO3 and ClONO2 and observationally derived ozone loss rates. The system of differential equations is not stiff and can be solved with a time step of one day, allowing many years to be processed per second on a standard PC. The inputs required are the daily fractions of the vortex area covered by polar stratospheric clouds and the fractions of the vortex area exposed to sunlight. The resultant model, SWIFT (Semi-empirical Weighted Iterative Fit Technique), provides a fast yet accurate method to simulate ozone loss rates in polar regions. SWIFT's capabilities are demonstrated by comparing measured and modeled total ozone loss outside of the training period.

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Technical Note: SWIFT – a fast semi-empirical model for polar stratospheric ozone loss

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-6545-2014 ◽

2014 ◽

Vol 14 (13) ◽

pp. 6545-6555 ◽

Cited By ~ 3

Author(s):

M. Rex ◽

S. Kremser ◽

P. Huck ◽

G. Bodeker ◽

I. Wohltmann ◽

...

Keyword(s):

Differential Equations ◽

Stratospheric Ozone ◽

Accurate Method ◽

Technical Note ◽

Rate Of Change ◽

Polar Regions ◽

Time Step ◽

Ozone Loss ◽

Semi Empirical ◽

Loss Rates

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A Match-based approach to the estimation of polar stratospheric ozone loss using Aura Microwave Limb Sounder observations

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-9945-2015 ◽

2015 ◽

Vol 15 (17) ◽

pp. 9945-9963 ◽

Cited By ~ 21

Author(s):

N. J. Livesey ◽

M. L. Santee ◽

G. L. Manney

Keyword(s):

Stratospheric Ozone ◽

Potential Temperature ◽

Polar Vortex ◽

Rate Of Change ◽

The Arctic ◽

Air Mass ◽

Ozone Loss ◽

Chemical Destruction ◽

Induced Changes ◽

The Impact

Abstract. The well-established "Match" approach to quantifying chemical destruction of ozone in the polar lower stratosphere is applied to ozone observations from the Microwave Limb Sounder (MLS) on NASA's Aura spacecraft. Quantification of ozone loss requires distinguishing transport- and chemically induced changes in ozone abundance. This is accomplished in the Match approach by examining cases where trajectories indicate that the same air mass has been observed on multiple occasions. The method was pioneered using ozonesonde observations, for which hundreds of matched ozone observations per winter are typically available. The dense coverage of the MLS measurements, particularly at polar latitudes, allows matches to be made to thousands of observations each day. This study is enabled by recently developed MLS Lagrangian trajectory diagnostic (LTD) support products. Sensitivity studies indicate that the largest influence on the ozone loss estimates are the value of potential vorticity (PV) used to define the edge of the polar vortex (within which matched observations must lie) and the degree to which the PV of an air mass is allowed to vary between matched observations. Applying Match calculations to MLS observations of nitrous oxide, a long-lived tracer whose expected rate of change is negligible on the weekly to monthly timescales considered here, enables quantification of the impact of transport errors on the Match-based ozone loss estimates. Our loss estimates are generally in agreement with previous estimates for selected Arctic winters, though indicating smaller losses than many other studies. Arctic ozone losses are greatest during the 2010/11 winter, as seen in prior studies, with 2.0 ppmv (parts per million by volume) loss estimated at 450 K potential temperature (~ 18 km altitude). As expected, Antarctic winter ozone losses are consistently greater than those for the Arctic, with less interannual variability (e.g., ranging between 2.3 and 3.0 ppmv at 450 K). This study exemplifies the insights into atmospheric processes that can be obtained by applying the Match methodology to a densely sampled observation record such as that from Aura MLS.

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Comment on "Cosmic-ray-driven reaction and greenhouse effect of halogenated molecules: Culprits for atmospheric ozone depletion and global climate change"

International Journal of Modern Physics B ◽

10.1142/s0217979214820013 ◽

2014 ◽

Vol 28 (13) ◽

pp. 1482001 ◽

Cited By ~ 3

Author(s):

Rolf Müller ◽

Jens-Uwe Grooß

Keyword(s):

Climate Change ◽

Sea Level ◽

Total Ozone ◽

Stratospheric Ozone ◽

Cosmic Ray ◽

Alternative Mechanism ◽

Ozone Loss ◽

Global Sea Level ◽

The Impact ◽

Loss Rates

Lu's "cosmic-ray-driven electron-induced reaction (CRE) theory" is based on the assumption that the CRE reaction of halogenated molecules (e.g., chlorofluorocarbons (CFCs), HCl, ClONO2) adsorbed or trapped in polar stratospheric clouds in the winter polar stratosphere is the key step in forming photoactive halogen species that are the cause of the springtime ozone hole. This theory has been extended to a warming theory of halogenated molecules for climate change. In this comment, we discuss the chemical and physical foundations of these theories and the conclusions derived from the theories. First, it is unclear whether the loss rates of halogenated molecules induced by dissociative electron attachment (DEA) observed in the laboratory can also be interpreted as atmospheric loss rates, but even if this were the case, the impact of DEA-induced reactions on polar chlorine activation and ozone loss in the stratosphere is limited. Second, we falsify several conclusions that are reported on the basis of the CRE theory: There is no polar ozone loss in darkness, there is no apparent 11-year periodicity in polar total ozone measurements, the age of air in the polar lower stratosphere is much older than 1–2 years, and the reported detection of a pronounced recovery (by about 20–25%) in Antarctic total ozone measurements by the year 2010 is in error. There are also conclusions about the future development of sea ice and global sea level which are fundamentally flawed because Archimedes' principle is neglected. Many elements of the CRE theory are based solely on correlations between certain datasets which are no substitute for providing physical and chemical mechanisms causing a particular behavior noticeable in observations. In summary, the CRE theory cannot be considered as an independent, alternative mechanism for polar stratospheric ozone loss and the conclusions on recent and future surface temperature and global sea level change do not have a physical basis.

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Match observations in the Arctic winter 1996/97: High stratospheric ozone loss rates correlate with low temperatures deep inside the polar vortex

Geophysical Research Letters ◽

10.1029/1999gl010811 ◽

2000 ◽

Vol 27 (2) ◽

pp. 205-208 ◽

Cited By ~ 50

Author(s):

A. Schulz ◽

M. Rex ◽

J. Steger ◽

N. R. P. Harris ◽

G. O. Braathen ◽

...

Keyword(s):

Low Temperatures ◽

Stratospheric Ozone ◽

Polar Vortex ◽

The Arctic ◽

Ozone Loss ◽

Loss Rates

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A Match-based approach to the estimation of polar stratospheric ozone loss using Aura Microwave Limb Sounder observations

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-10041-2015 ◽

2015 ◽

Vol 15 (7) ◽

pp. 10041-10083 ◽

Cited By ~ 2

Author(s):

N. J. Livesey ◽

M. L. Santee ◽

G. L. Manney

Keyword(s):

Stratospheric Ozone ◽

Potential Temperature ◽

Polar Vortex ◽

Rate Of Change ◽

The Arctic ◽

Ozone Loss ◽

Chemically Induced ◽

Chemical Destruction ◽

Induced Changes ◽

The Impact

Abstract. The well-established "Match" approach to quantifying chemical destruction of ozone in the polar lower stratosphere is applied to ozone observations from the Microwave Limb Sounder (MLS) on NASA's Aura spacecraft. Quantification of ozone loss requires distinguishing transport- and chemically induced changes in ozone abundance. This is accomplished in the Match approach by examining cases where trajectories indicate that the same airmass has been observed on multiple occasions. The method was pioneered using ozone sonde observations, for which hundreds of matched ozone observations per winter are typically available. The dense coverage of the MLS measurements, particularly at polar latitudes, allows matches to be made to thousands of observations each day. This study is enabled by recently developed MLS Lagrangian Trajectory Diagnostic (LTD) support products. Sensitivity studies indicate that the largest influence on the ozone loss estimates are the value of potential vorticity (PV) used to define the edge of the polar vortex (within which matched observations must lie) and the degree to which the PV of an airmass is allowed to vary between matched observations. Applying Match calculations to MLS observations of nitrous oxide, a long-lived tracer whose expected rate of change on these timescales is negligible, enables quantification of the impact of transport errors on the Match-based ozone loss estimates. Our loss estimates are generally in agreement with previous estimates for selected Arctic winters, though indicating smaller losses than many other studies. Arctic ozone losses are greatest during the 2010/11 winter, as seen in prior studies, with 2.0 ppmv (parts per million by volume) loss estimated at 450 K potential temperature. As expected, Antarctic winter ozone losses are consistently greater than those for the Arctic, with less interannual variability (e.g., ranging between 2.3 and 3.0 ppmv at 450 K). This study exemplifies the insights into atmospheric processes that can be obtained by applying the Match methodology to a densely sampled observation record such as that from Aura MLS.

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Evidence for slowdown in stratospheric ozone loss: first stage of ozone recovery

Nature ◽

10.1038/news030728-5 ◽

2003 ◽

Keyword(s):

Stratospheric Ozone ◽

Ozone Loss

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Technical Note: Quantification of interferences of wet chemical HONO LOPAP measurements under simulated polar conditions

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-6813-2008 ◽

2008 ◽

Vol 8 (22) ◽

pp. 6813-6822 ◽

Cited By ~ 51

Author(s):

J. Kleffmann ◽

P. Wiesen

Keyword(s):

Technical Note ◽

Swiss Alps ◽

Pollution Level ◽

Research Station ◽

Polar Regions ◽

Alpine Research ◽

Absorption Photometer ◽

Present Pilot Study ◽

Good Agreement

Abstract. In the present pilot study, an optimized LOPAP instrument (LOng Path Absorption Photometer) for the detection of nitrous acid (HONO) in the atmosphere (DL 0.2 pptV) was tested at the high alpine research station Jungfraujoch at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range <0.5–50 pptV with an average of 7.5 pptV were observed at the Jungfraujoch. The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the active correction of interferences is of paramount importance for the determination of reliable HONO data.

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The evolution of turbulent bursts: the b—ε model

European Journal of Applied Mathematics ◽

10.1017/s0956792500001601 ◽

1994 ◽

Vol 5 (4) ◽

pp. 537-557 ◽

Cited By ~ 5

Author(s):

M. Bertsch ◽

R. Dal Passo ◽

R. Kersner

Keyword(s):

Partial Differential Equations ◽

Energy Dissipation ◽

Energy Density ◽

Differential Equations ◽

Dissipation Rate ◽

Turbulent Energy ◽

Energy Dissipation Rate ◽

Self Similar ◽

FINITE ELEMENT METHODS FOR NONLINEAR ACOUSTICS IN FLUIDS

Journal of Computational Acoustics ◽

10.1142/s0218396x0700338x ◽

2007 ◽

Vol 15 (03) ◽

pp. 353-375 ◽

Cited By ~ 14

Author(s):

TIMOTHY WALSH ◽

MONICA TORRES

Keyword(s):

Finite Element ◽

Partial Differential Equations ◽

Differential Equations ◽

Nonlinear Acoustics ◽

Time Step ◽

Partial Differential ◽

Time Step Size ◽

Finite Element Discretizations ◽

Acoustic Fluid ◽

Element Discretizations

In this paper, weak formulations and finite element discretizations of the governing partial differential equations of three-dimensional nonlinear acoustics in absorbing fluids are presented. The fluid equations are considered in an Eulerian framework, rather than a displacement framework, since in the latter case the corresponding finite element formulations suffer from spurious modes and numerical instabilities. When taken with the governing partial differential equations of a solid body and the continuity conditions, a coupled formulation is derived. The change in solid/fluid interface conditions when going from a linear acoustic fluid to a nonlinear acoustic fluid is demonstrated. Finite element discretizations of the coupled problem are then derived, and verification examples are presented that demonstrate the correctness of the implementations. We demonstrate that the time step size necessary to resolve the wave decreases as steepening occurs. Finally, simulation results are presented on a resonating acoustic cavity, and a coupled elastic/acoustic system consisting of a fluid-filled spherical tank.

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Record springtime stratospheric ozone depletion at 80°N in 2020

10.5194/egusphere-egu21-8892 ◽

2021 ◽

Author(s):

Ramina Alwarda ◽

Kristof Bognar ◽

Kimberly Strong ◽

Martyn Chipperfield ◽

Sandip Dhomse ◽

...

Keyword(s):

Ozone Depletion ◽

Transport Model ◽

Stratospheric Ozone ◽

Polar Vortex ◽

The Arctic ◽

Optical Absorption Spectroscopy ◽

Chemical Transport Model ◽

Polar Stratospheric Clouds ◽

Ozone Loss ◽

Stratospheric Clouds

The Arctic winter of 2019-2020 was characterized by an unusually persistent polar vortex and temperatures in the lower stratosphere that were consistently below the threshold for the formation of polar stratospheric clouds (PSCs). These conditions led to ozone loss that is comparable to the Antarctic ozone hole. Ground-based measurements from a suite of instruments at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Canada (80.05&#176;N, 86.42&#176;W) were used to investigate chemical ozone depletion. The vortex was located above Eureka longer than in any previous year in the 20-year dataset and lidar measurements provided evidence of polar stratospheric clouds (PSCs) above Eureka. Additionally, UV-visible zenith-sky Differential Optical Absorption Spectroscopy (DOAS) measurements showed record ozone loss in the 20-year dataset, evidence of denitrification along with the slowest increase of NO2 during spring, as well as enhanced reactive halogen species (OClO and BrO). Complementary measurements of HCl and ClONO2 (chlorine reservoir species) from a Fourier transform infrared (FTIR) spectrometer showed unusually low columns that were comparable to 2011, the previous year with significant chemical ozone depletion. Record low values of HNO3 in the FTIR dataset are in accordance with the evidence of PSCs and a denitrified atmosphere. Estimates of chemical ozone loss were derived using passive ozone from the SLIMCAT offline chemical transport model to account for dynamical contributions to the stratospheric ozone budget.

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