scholarly journals Forecasts and assimilation experiments of the Antarctic ozone hole 2008

2011 ◽  
Vol 11 (5) ◽  
pp. 1961-1977 ◽  
Author(s):  
J. Flemming ◽  
A. Inness ◽  
L. Jones ◽  
H. J. Eskes ◽  
V. Huijnen ◽  
...  
Keyword(s):  
Transport Model ◽  
Initial Conditions ◽  
Stratospheric Ozone ◽  
Satellite Observations ◽  
Ozone Hole ◽  
Chemical Mechanism ◽  
Ozone Monitoring Instrument ◽  
Variable Effect ◽  
Antarctic Ozone ◽  
Antarctic Ozone Hole

Abstract. The 2008 Antarctic ozone hole was one of the largest and most long-lived in recent years. Predictions of the ozone hole were made in near-real time (NRT) and hindcast mode with the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The forecasts were carried out both with and without assimilation of satellite observations from multiple instruments to provide more realistic initial conditions. Three different chemistry schemes were applied for the description of stratospheric ozone chemistry: (i) a linearization of the ozone chemistry, (ii) the stratospheric chemical mechanism of the Model of Ozone and Related Chemical Tracers, version 3, (MOZART-3) and (iii) the relaxation to climatology as implemented in the Transport Model, version 5, (TM5). The IFS uses the latter two schemes by means of a two-way coupled system. Without assimilation, the forecasts showed model-specific shortcomings in predicting start time, extent and duration of the ozone hole. The assimilation of satellite observations from the Microwave Limb Sounder (MLS), the Ozone Monitoring Instrument (OMI), the Solar Backscattering Ultraviolet radiometer (SBUV-2) and the SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) led to a significant improvement of the forecasts when compared with total columns and vertical profiles from ozone sondes. The combined assimilation of observations from multiple instruments helped to overcome limitations of the ultraviolet (UV) sensors at low solar elevation over Antarctica. The assimilation of data from MLS was crucial to obtain a good agreement with the observed ozone profiles both in the polar stratosphere and troposphere. The ozone analyses by the three model configurations were very similar despite the different underlying chemistry schemes. Using ozone analyses as initial conditions had a very beneficial but variable effect on the predictability of the ozone hole over 15 days. The initialized forecasts with the MOZART-3 chemistry produced the best predictions of the increasing ozone hole whereas the linear scheme showed the best results during the ozonehole closure.

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

2017 ◽  
Vol 17 (3) ◽  
pp. 1673-1688 ◽  
Author(s):  
Rafael P. Fernandez ◽  
Douglas E. Kinnison ◽  
Jean-Francois Lamarque ◽  
Simone Tilmes ◽  
Alfonso Saiz-Lopez
Keyword(s):  
21St Century ◽  
Stratospheric Ozone ◽  
Montreal Protocol ◽  
Ozone Hole ◽  
Community Atmosphere Model ◽  
Hole Area ◽  
Photochemical Decomposition ◽  
Antarctic Ozone ◽  
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, which is 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 (Community Atmosphere Model with Chemistry, version 4.0) does not introduce a significant delay of the modelled ozone return date to 1980 October levels, but instead affects 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 the 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.

Large Increase in Incident Shortwave Radiation due to the Ozone Hole Offset by High Climatological Albedo over Antarctica

2017 ◽  
Vol 30 (13) ◽  
pp. 4883-4890 ◽  
Author(s):  
G. Chiodo ◽  
L. M. Polvani ◽  
M. Previdi
Keyword(s):  
Surface Temperature ◽  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Surface Energy Budget ◽  
Ozone Hole ◽  
Radiative Heating ◽  
Shortwave Radiation ◽  
Stratospheric Ozone Depletion ◽  
Continental Scale

Despite increasing scientific scrutiny in recent years, the direct impact of the ozone hole on surface temperatures over Antarctica remains uncertain. Here, this question is explored by using the Community Earth System Model–Whole Atmosphere Community Climate Model (CESM-WACCM), contrasting two ensembles of runs with and without stratospheric ozone depletion. It is found that, during austral spring, the ozone hole leads to a surprisingly large increase in surface downwelling shortwave (SW) radiation over Antarctica of 3.8 W m−2 in clear sky and 1.8 W m−2 in all sky. However, despite this large increase in incident SW radiation, no ozone-induced surface warming is seen in the model. It is shown that the lack of a surface temperature response is due to reflection of most of the increased downward SW, resulting in an insignificant change to the net SW radiative heating. To first order, this reflection is simply due to the high climatological surface albedo of the Antarctic snow (97% in visible SW), resulting in a net zero ozone-induced surface SW forcing. In addition, it is shown that stratospheric ozone depletion has a negligible effect on longwave (LW) radiation and other components of the surface energy budget. These results suggest a minimal role for ozone depletion in forcing Antarctic surface temperature trends on a continental scale.

scholarly journals The Antarctic ozone hole during 2015 and 2016

2019 ◽  
Vol 69 (1) ◽  
pp. 16
Author(s):  
Matthew B. Tully ◽  
Andrew R. Klekociuk ◽  
Paul B. Krummel ◽  
H. Peter Gies ◽  
Simon P. Alexander ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Ozone Depletion ◽  
Volcanic Eruption ◽  
Stratospheric Aerosol ◽  
Satellite Observations ◽  
Ozone Hole ◽  
Maximum Area ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Antarctic Ozone Hole

We reviewed the 2015 and 2016 Antarctic ozone holes, making use of a variety of ground-based and spacebased measurements of ozone and ultraviolet radiation, supplemented by meteorological reanalyses. The ozone hole of 2015 was one of the most severe on record with respect to maximum area and integrated deficit and was notably longlasting, with many values above previous extremes in October, November and December. In contrast, all assessed metrics for the 2016 ozone hole were at or below their median values for the 37 ozone holes since 1979 for which adequate satellite observations exist. The 2015 ozone hole was influenced both by very cold conditions and enhanced ozone depletion caused by stratospheric aerosol resulting from the April 2015 volcanic eruption of Calbuco (Chile).

scholarly journals Forecasts and assimilation experiments of the Antarctic Ozone Hole 2008

2010 ◽  
Vol 10 (4) ◽  
pp. 9173-9217 ◽  
Author(s):  
J. Flemming ◽  
A. Inness ◽  
L. Jones ◽  
H. J. Eskes ◽  
V. Huijnen ◽  
...  
Keyword(s):  
Transport Model ◽  
Initial Conditions ◽  
Stratospheric Ozone ◽  
Satellite Observations ◽  
Ozone Hole ◽  
Chemical Mechanism ◽  
Ozone Monitoring Instrument ◽  
Start Time ◽  
Antarctic Ozone ◽  
Antarctic Ozone Hole

Abstract. The 2008 Antarctic ozone hole was one of the largest and most long-lived in recent years. Predictions of the ozone hole were made in near-real time (NRT) and hindcast mode with the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The forecasts were carried out both with and without assimilation of satellite observations from multiple instruments to provide more realistic initial conditions. Three different chemistry schemes were applied for the description of stratospheric ozone chemistry: (i) a linearization of the ozone chemistry, (ii) the stratospheric chemical mechanism of the MOZART-3 chemical transport model (CTM) and (iii) the relaxation to a climatology as implemented in the TM5 CTM. The IFS uses the latter two schemes by means of a two-way coupled system. Without assimilation, the forecasts showed model-specific shortcomings in predicting start time, extent and duration of the ozone hole. The assimilation of satellite observations from the Microwave Limb Sounder (MLS), the Ozone Monitoring Instrument (OMI), the Solar Backscattering Ultraviolet radiometer (SBUV-2) and the SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) led to a significant improvement of the forecasts when compared with total columns and vertical profiles from ozone sondes. The combined assimilation of observations from multiple instruments helped to overcome limitations of the ultraviolet (UV) sensors at low solar elevation over Antarctica. The assimilation of data from MLS was crucial to obtain a good agreement with the observed ozone profiles both in the polar stratosphere and troposphere. The ozone analyses by the three model configurations were very similar despite the different underlying chemistry schemes. During the chemically instigated development of the ozone hole, differences quickly developed in the initialized forecasts by the different schemes. The predictions of the ozone-hole closure, which is driven mainly by dynamical processes, benefited from the initialization over a much longer forecast length. The characteristics of the individual chemistry schemes became apparent after the third forecast day but the forecasts were still close to the respective analyses. The initialization with ozone analyses was beneficial up to at least 15 days.

scholarly journals Nadir ozone profile retrieval from SCIAMACHY and its application to the Antarctic ozone hole in the period 2003–2011

2017 ◽  
Author(s):  
Sweta Shah ◽  
Olaf Tuinder ◽  
Jacob van Peet ◽  
Adrianus de Laat ◽  
Piet Stammes
Keyword(s):  
Spectral Response ◽  
Stratospheric Ozone ◽  
Ozone Hole ◽  
Retrieval Algorithm ◽  
Latitude Range ◽  
Ozone Profile ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Ozone Column ◽  
Antarctic Ozone Hole

Abstract. The depletion of the Antarctic ozone layer and its changing vertical distribution has been monitored closely by satellites in the past decades ever since the Antarctic ozone hole was discovered in the 1980's. Ozone profile retrieval from nadir-viewing satellites operating in the ultraviolet-visible range requires accurate calibration of level-1 (L1) radiance data. Here we study the effects of calibration on the derived level-2 (L2) ozone profiles and apply the retrieval to the Antarctic ozone hole region. We retrieve nadir ozone profiles from the SCIAMACHY instrument that flew on-board Envisat using the Ozone ProfilE Retrieval Algorithm) (OPERA) developed at KNMI with a focus on the stratospheric ozone. We study and assess the quality of these profiles and compare retrieved (L2) products from L1 SCIAMACHY versions 7 and 8 indicated as respectively (v7, v8) data from the years 2003–2011 without further radiometric correction. From validation of the profiles against ozone sonde measurements, we find that the v8 performs better due to correction for the scan-angle dependency of the instrument's optical degradation. The instrument spectral response function can still be improved for the L1 v8 data with a shift and squeeze. We find that the contribution from this improvement is a few percent residue reduction compared to a reference in the solar irradiance spectra. Validation for the years 2003 and 2009 with ozone sondes shows deviations of SCIAMACHY ozone profiles of 0.8 %–15 % in the stratosphere and 2.5 %–100 % in the troposphere, depending on the latitude and the L1 version used. Using L1 v8 for the years 2003–2011 leads to deviations of ~ 1 %–11 % in stratospheric ozone and ~ 1 %–45 % in tropospheric ozone. Application of SCIAMACHY v8 data on the Antarctic ozone hole shows that most ozone is depleted in the latitude range from 70° S to 90° S. The minimum integrated ozone column consistently occurs around 15 September for the years 2003–2011. Furthermore from the ozone profiles for all these years we observe that the value of ozone column per layer reduces to almost zero at a pressure of 100 hPa in the latitude range of 70° S to 90° S, as was found from other observations.

scholarly journals Drivers of the Recent Tropical Expansion in the Southern Hemisphere: Changing SSTs or Ozone Depletion?

2015 ◽  
Vol 28 (16) ◽  
pp. 6581-6586 ◽  
Author(s):  
Darryn W. Waugh ◽  
Chaim I. Garfinkel ◽  
Lorenzo M. Polvani
Keyword(s):  
Ozone Depletion ◽  
Meta Analysis ◽  
Stratospheric Ozone ◽  
Austral Summer ◽  
Hadley Cell ◽  
Sea Surface ◽  
Relative Role ◽  
Stratospheric Ozone Depletion ◽  
Antarctic Ozone

Abstract Observational evidence indicates that the southern edge of the Hadley cell (HC) has shifted southward during austral summer in recent decades. However, there is no consensus on the cause of this shift, with several studies reaching opposite conclusions as to the relative role of changes in sea surface temperatures (SSTs) and stratospheric ozone depletion in causing this shift. Here, the authors perform a meta-analysis of the extant literature on this subject and quantitatively compare the results of all published studies that have used single-forcing model integrations to isolate the role of different factors on the HC expansion during austral summer. It is shown that the weight of the evidence clearly points to stratospheric ozone depletion as the dominant driver of the tropical summertime expansion over the period in which an ozone hole was formed (1979 to late 1990s), although SST trends have contributed to trends since then. Studies that have claimed SSTs as the major driver of tropical expansion since 1979 have used prescribed ozone fields that underrepresent the observed Antarctic ozone depletion.

scholarly journals The Antarctic ozone hole during 2017

2019 ◽  
Vol 69 (1) ◽  
pp. 29
Author(s):  
Andrew R. Klekociuk ◽  
Matthew B. Tully ◽  
Paul B. Krummel ◽  
Oleksandr Evtushevsky ◽  
Volodymyr Kravchenko ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Wave Activity ◽  
Ozone Hole ◽  
Quasi Biennial Oscillation ◽  
Ozone Loss ◽  
Hole Making ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Antarctic Ozone Hole

We review the 2017 Antarctic ozone hole, making use of various meteorological reanalyses, and in-situ, satellite and ground-based measurements of ozone and related trace gases, and ground-based measurements of ultraviolet radiation. The 2017 ozone hole was associated with relatively high-ozone concentrations over the Antarctic region compared to other years, and our analysis ranked it in the smallest 25% of observed ozone holes in terms of size. The severity of stratospheric ozone loss was comparable with that which occurred in 2002 (when the stratospheric vortex exhibited an unprecedented major warming) and most years prior to 1989 (which were early in the development of the ozone hole). Disturbances to the polar vortex in August and September that were associated with intervals of anomalous planetary wave activity resulted in significant erosion of the polar vortex and the mitigation of the overall level of ozone depletion. The enhanced wave activity was favoured by below-average westerly winds at high southern latitudes during winter, and the prevailing easterly phase of the quasi-biennial oscillation (QBO). Using proxy information on the chemical make-up of the polar vortex based on the analysis of nitrous oxide and the likely influence of the QBO, we suggest that the concentration of inorganic chlorine, which plays a key role in ozone loss, was likely similar to that in 2014 and 2016, when the ozone hole was larger than that in 2017. Finally, we found that the overall severity of Antarctic ozone loss in 2017 was largely dictated by the timing of the disturbances to the polar vortex rather than interannual variability in the level of inorganic chlorine.

scholarly journals Strong Dynamical Modulation of the Cooling of the Polar Stratosphere Associated with the Antarctic Ozone Hole

2012 ◽  
Vol 26 (2) ◽  
pp. 662-668 ◽  
Author(s):  
Andrew Orr ◽  
Thomas J. Bracegirdle ◽  
J. Scott Hosking ◽  
Wuhu Feng ◽  
Howard K. Roscoe ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Model Simulation ◽  
Early Summer ◽  
Ozone Hole ◽  
Radiative Cooling ◽  
Cold Anomaly ◽  
Antarctic Ozone ◽  
Polar Stratosphere ◽  
The Antarctic ◽  
Antarctic Ozone Hole

Abstract A model simulation forced by prescribed ozone depletion shows strong dynamical modulation of the springtime cooling of the polar stratosphere associated with the Antarctic ozone hole. The authors find that in late spring the anomalous radiative cooling in response to ozone depletion is almost canceled above ~100 hPa by an increase in dynamical heating. Between ~300 and ~100 hPa, however, it is enhanced by a reduction in dynamical heating, resulting in the descent of the cold anomaly down to the tropopause. In early summer increased dynamical heating dominates as the radiative cooling diminishes so that the cold anomaly associated with the delayed breakup of the stratospheric vortex is reduced. The anomalous dynamical heating is driven by changes in the Brewer–Dobson circulation arising primarily from the dissipation of resolved-scale waves. The model changes are broadly consistent with trends from reanalysis and offline diagnoses of heating rates using a radiation scheme. These results help one to understand dynamically induced change in the evolution and timing of the stratospheric vortex in recent decades and will help to enable improved simulation of the Southern Hemisphere climate.

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