scholarly journals Rapid increase in dichloromethane emissions from China inferred through atmospheric observations

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Minde An ◽  
Luke M. Western ◽  
Daniel Say ◽  
Liqu Chen ◽  
Tom Claxton ◽  
...  
Keyword(s):  
Eastern China ◽  
Montreal Protocol ◽  
Successful Implementation ◽  
Annual Increase ◽  
Global Emission ◽  
Atmospheric Observations ◽  
Antarctic Ozone ◽  
Ozone Depleting Substances ◽  
The Antarctic ◽  
Antarctic Ozone Hole

AbstractWith the successful implementation of the Montreal Protocol on Substances that Deplete the Ozone Layer, the atmospheric abundance of ozone-depleting substances continues to decrease slowly and the Antarctic ozone hole is showing signs of recovery. However, growing emissions of unregulated short-lived anthropogenic chlorocarbons are offsetting some of these gains. Here, we report an increase in emissions from China of the industrially produced chlorocarbon, dichloromethane (CH2Cl2). The emissions grew from 231 (213–245) Gg yr−1 in 2011 to 628 (599–658) Gg yr−1 in 2019, with an average annual increase of 13 (12–15) %, primarily from eastern China. The overall increase in CH2Cl2 emissions from China has the same magnitude as the global emission rise of 354 (281−427) Gg yr−1 over the same period. If global CH2Cl2 emissions remain at 2019 levels, they could lead to a delay in Antarctic ozone recovery of around 5 years compared to a scenario with no CH2Cl2 emissions.

scholarly journals Dynamical modes associated with the Antarctic ozone hole

2009 ◽  
Vol 9 (15) ◽  
pp. 5403-5416 ◽  
Author(s):  
B. C. Weare
Keyword(s):  
Transport Processes ◽  
Ozone Hole ◽  
Mixing Ratio ◽  
Asymmetric Mode ◽  
Maximum Covariance Analysis ◽  
Antarctic Ozone ◽  
Ozone Depleting Substances ◽  
The Antarctic ◽  
Ozone Variations ◽  
Antarctic Ozone Hole

Abstract. Generalized Maximum Covariance Analysis (GMCA) has been developed and applied to diagnosing the dynamical modes associated with variations in the Antarctic spring ozone hole. GMCA is used to identify the most important patterns of co-variability between interannual ozone mixing ratio variations in the Antarctic region and temperature, zonal, meridional and vertical velocities between 100 and 10 hPa in the same region. The most important two pairs of GMCA time coefficients show large year-to-year variations and trends, which are connected with the growth of the Antarctic Ozone Hole and the increase of ozone depleting substances. The associated spatial patterns of ozone variations may be characterized as being quasi-symmetric and asymmetric about the pole. These patterns of ozone variations are associated with comparable patterns of variations of temperature and winds through most of the vertical domain. The year 2000 is shown to be dominated by the asymmetric mode, whereas the adjacent year 2001 is dominated by the quasi-symmetric mode. A case study, focusing on the asymmetric differences between these two years, shows the magnitude of the ozone mixing ratio, temperature and zonal wind differences to be in the range of 2 e–6 kg/kg, 10°C and 10 m/s, respectively. Budget calculations show that transport processes contribute substantially to the ozone and temperature changes in the middle stratosphere over the Antarctic continent. However, both radiative and chemical processes also play important roles in the changes.

scholarly journals Delay in recovery of the Antarctic ozone hole from unexpected CFC-11 emissions

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
S. S. Dhomse ◽  
W. Feng ◽  
S. A. Montzka ◽  
R. Hossaini ◽  
J. Keeble ◽  
...  
Keyword(s):  
Montreal Protocol ◽  
Ozone Hole ◽  
Atmospheric Variability ◽  
Gas Emissions ◽  
Model Simulations ◽  
The Future ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
The Impact ◽  
Antarctic Ozone Hole

AbstractThe Antarctic ozone hole is decreasing in size but this recovery will be affected by atmospheric variability and any unexpected changes in chlorinated source gas emissions. Here, using model simulations, we show that the ozone hole will largely cease to occur by 2065 given compliance with the Montreal Protocol. If the unusual meteorology of 2002 is repeated, an ozone-hole-free-year could occur as soon as the early 2020s by some metrics. The recently discovered increase in CFC-11 emissions of ~ 13 Gg yr−1 may delay recovery. So far the impact on ozone is small, but if these emissions indicate production for foam use much more CFC-11 may be leaked in the future. Assuming such production over 10 years, disappearance of the ozone hole will be delayed by a few years, although there are significant uncertainties. Continued, substantial future CFC-11 emissions of 67 Gg yr−1 would delay Antarctic ozone recovery by well over a decade.

QUASI-BIENNIAL OSCILLATION OF ZONAL WIND IN THE EQUATORIAL STRATOSPHERE AND ITS INFLUENCE ON INTERANNUAL FLUCTUATIONS IN THE DEPTH OF THE ANTARCTIC OZONE HOLE

2021 ◽  
pp. 5-15
Author(s):  
I. P. Gabis ◽  
Keyword(s):  
Ozone Hole ◽  
Anthropogenic Factors ◽  
Quasi Biennial Oscillation ◽  
Antarctic Ozone ◽  
Interannual Fluctuations ◽  
Ozone Depleting Substances ◽  
The Antarctic ◽  
Biennial Oscillation ◽  
Antarctic Ozone Hole

The Antarctic ozone hole is observed annually in spring due to the complex influence of photochemical and dynamical processes. The increased concentration of ozone-depleting substances in the atmosphere causes a long-term negative trend in total ozone (TO). Intense interannual fluctuations in TO against a background of the long-term trend associated with dynamic atmospheric processes do not allow assessing definitely the direction of the trend (growth/decline) in the recent years. Studying the dependence of interannual fluctuations in the ozone hole intensity on the equatorial quasi-biennial oscillation (QBO) allows identifying natural causes of variations and assessing the trend due to anthropogenic factors. The long-term QBO forecast allows predicting different phenomena that depend on the QBO.

Global and regional emission estimates for three ozone-depleting hydrochlorofluoro-carbons (HCFCs) with no known end-uses

2020 ◽  
Author(s):  
Martin Vollmer ◽  
Keyword(s):  
Eastern China ◽  
Montreal Protocol ◽  
Lagrangian Model ◽  
Vienna Convention ◽  
Fully Integrated ◽  
First Results ◽  
Atmospheric Observations ◽  
Ozone Depleting Substances ◽  
Phase Out ◽  
Global Emissions

<p>We present first results on atmospheric abundances and inferred emissions of the previously undetected ozone depleting hydrochlorofluorocarbon HCFC-132b (1,2-dichloro-1,1-difluoroethane). In addition we report significant updates on observations and inferred emissions for HCFC-133a (2-chloro-1,1,1-trifluoroethane) and HCFC-31 (chlorofluoromethane). All three compounds are Ozone Depleting Substances (ODSs) and their productions are regulated under the Montreal Protocol on Substances that Deplete the Ozone Layer. However, they are not known as end-user products from which potential emissions to the atmosphere could occur. Rather, we hypothesize that the compounds are emitted as byproducts during the production of hydrofluorocarbons (HFCs). If this holds true, then the phase-out regulations of the Protocol do not apply to them, nevertheless the Protocol's overarching Vienna Convention encourages the parties to minimize such ODS byproduct emissions.</p><p>In-situ fully intercalibrated high-precision measurements of the recently discovered HCFC-132b have been made for several years at the stations of the Advanced Global Atmospheric Gases Experiment (AGAGE) and are complemented with measurements from archived air samples (1978 – present) of the Cape Grim Air Archive. Based on these measurements we reconstruct global HCFC-132b trends showing its first appearance in the atmosphere in the late 1990s, followed by a general growth in the atmosphere to current globally-averaged mole fractions of approx. 0.13 ppt (picomol mol<sup>-1</sup>). Global emissions, which are derived from these observations using the AGAGE 12-box model, show a general increase to approx. 1 Gg yr<sup>-1</sup> in 2019. Observation-based top-down regional emission estimates for the East-Asian region, as derived from a Bayesian inversion with the FLEXPART Lagrangian model, can explain all of the global emissions within the uncertainties of the method. Half of these emissions are allocated to Eastern China, a region where enhanced emissions for other ODSs were previously found. Emissions from Europe are comparably insignificant, but an analysis of the source locations supports the hypothesis that HCFC-132b emissions are a byproduct from HFC production. In addition to HCFC-132b, we present significant updates on observations of HCFC-133a and HCFC-31. HCFC-133a measurements are now fully integrated into the AGAGE network and provide a wealth of atmospheric observations. Similar to HCFC-132b, we show, for example, that abundances and global emissions of these two compounds have generally increased over the last few years.</p>

scholarly journals Impact of biogenic very short-lived bromine on the Antarctic ozone hole during the 21<sup>st</sup> century

2016 ◽  
Author(s):  
Rafael P. Fernandez ◽  
Douglas E. Kinnison ◽  
Jean-Francois Lamarque ◽  
Simone Tilmes ◽  
Alfonso Saiz-Lopez
Keyword(s):  
Stratospheric Ozone ◽  
Montreal Protocol ◽  
Ozone Hole ◽  
Hole Area ◽  
Climate Simulations ◽  
Photochemical Decomposition ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
The Impact ◽  
Antarctic Ozone Hole

Abstract. Active bromine released from the photochemical decomposition of biogenic very short-lived bromocarbons (VSLBr) enhances stratospheric ozone depletion. Based on a dual set of 1960–2100 coupled chemistry-climate simulations (i.e. with and without VSLBr), we show that the maximum Antarctic ozone hole depletion increases by up to 14 % when natural VSLBr are considered, in better agreement with ozone observations. The impact of the additional 5 pptv VSLBr on Antarctic ozone is most evident in the periphery of the ozone hole, producing an expansion of the ozone hole area of ~5 million km2, which is equivalent in magnitude to the recently estimated Antarctic ozone healing due to the implementation of the Montreal Protocol. We find that the inclusion of VSLBr in CAM-Chem does not introduce a significant delay of the modelled ozone return date to 1980 October levels, but instead affect the depth and duration of the simulated ozone hole. Our analysis further shows that total bromine-catalysed ozone destruction in the lower stratosphere surpasses that of chlorine by year 2070, and indicates that natural VSLBr chemistry would dominate Antarctic ozone seasonality before the end of the 21st century. This work suggests a large influence of biogenic bromine on the future Antarctic ozone layer.

scholarly journals Dynamical modes associated with the Antarctic ozone hole

2009 ◽  
Vol 9 (1) ◽  
pp. 5055-5086
Author(s):  
B. C. Weare
Keyword(s):  
Transport Processes ◽  
Ozone Hole ◽  
Mixing Ratio ◽  
Asymmetric Mode ◽  
Maximum Covariance Analysis ◽  
Antarctic Ozone ◽  
Ozone Depleting Substances ◽  
The Antarctic ◽  
Ozone Variations ◽  
Antarctic Ozone Hole

Abstract. Generalized Maximum Covariance Analysis (GMCA) has been developed and applied to diagnosing the dynamical modes associated with variations in the Antarctic spring ozone hole. GMCA is used to identify the most important patterns of co-variability between interannual ozone mixing ratio variations in the Antarctic region and temperature, zonal, meridional and vertical velocities between 100 and 10 hPa in the same region. The most important two pairs of GMCA time coefficients show large year-to-year variations and trends, which are connected with the growth of the Antarctic Ozone Hole and the increase of ozone depleting substances. The associated spatial patterns of ozone variations may be characterized as being quasi-symmetric and asymmetric about the pole. These patterns of ozone variations are associated with comparable patterns of variations of temperature and winds through most of the vertical domain. The year 2000 is shown to be dominated by the asymmetric mode, whereas the adjacent year 2001 is dominated by the quasi-symmetric mode. A case study, focusing on the asymmetric differences between these two years, shows the magnitude of the ozone mixing ratio, temperature and zonal wind differences to be in the range of 2 e-6, 10°C and 10 m/s, respectively. Budget calculations show that transport processes contribute substantially to the ozone and temperature changes in the middle stratosphere over the Antarctic continent. However, both radiative and chemical processes also play important roles in the changes.

The discovery of the Antarctic ozone hole

Nature ◽  
2019 ◽  
Vol 575 (7781) ◽  
pp. 46-47 ◽  
Author(s):  
Susan Solomon
Keyword(s):  
Ozone Hole ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Antarctic Ozone Hole

scholarly journals How sensitive is the recovery of stratospheric ozone to changes in concentrations of very short-lived bromocarbons?

2014 ◽  
Vol 14 (19) ◽  
pp. 10431-10438 ◽  
Author(s):  
X. Yang ◽  
N. L. Abraham ◽  
A. T. Archibald ◽  
P. Braesicke ◽  
J. Keeble ◽  
...  
Keyword(s):  
Climate Model ◽  
Stratospheric Ozone ◽  
Montreal Protocol ◽  
Background Concentrations ◽  
Future Situation ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
The Impact ◽  
Ozone Column ◽  
Policy Question

Abstract. Naturally produced very short-lived substances (VSLS) account for almost a quarter of the current stratospheric inorganic bromine, Bry. Following VSLS oxidation, bromine radicals (Br and BrO) can catalytically destroy ozone. The extent to which possible increases in surface emissions or transport of these VSLS bromocarbons to the stratosphere could counteract the effect of halogen reductions under the Montreal Protocol is an important policy question. Here, by using a chemistry–climate model, UM-UKCA, we investigate the impact of a hypothetical doubling (an increase of 5 ppt Bry) of VSLS bromocarbons on ozone and how the resulting ozone changes depend on the background concentrations of chlorine and bromine. Our model experiments indicate that for the 5 ppt increase in Bry from VSLS, the ozone decrease in the lowermost stratosphere of the Southern Hemisphere (SH) may reach up to 10% in the annual mean; the ozone decrease in the Northern Hemisphere (NH) is smaller (4–6%). The largest impact on the ozone column is found in the Antarctic spring. There is a significantly larger ozone decrease following the doubling of the VSLS burden under a high stratospheric chlorine background than under a low chlorine background, indicating the importance of the inter-halogen reactions. For example, the decline in the high-latitude, lower-stratospheric ozone concentration as a function of Bry is higher by about 30–40% when stratospheric Cly is ~ 3 ppb (present day), compared with Cly of ~ 0.8 ppb (a pre-industrial or projected future situation). Bromine will play an important role in the future ozone layer. However, even if bromine levels from natural VSLS were to increase significantly later this century, changes in the concentration of ozone will likely be dominated by the decrease in anthropogenic chlorine. Our calculation suggests that for a 5 ppt increase in Bry from VSLS, the Antarctic ozone hole recovery date could be delayed by approximately 6–8 years, depending on Cly levels.

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