scholarly journals The 1985 Southern Hemisphere mid-latitude total column ozone anomaly

2007 ◽  
Vol 7 (21) ◽  
pp. 5625-5637 ◽  
Author(s):  
G. E. Bodeker ◽  
H. Garny ◽  
D. Smale ◽  
M. Dameris ◽  
R. Deckert
Keyword(s):  
Solar Cycle ◽  
Southern Hemisphere ◽  
Climate Model ◽  
Quasi Biennial Oscillation ◽  
Total Column Ozone ◽  
Column Ozone ◽  
Biennial Oscillation ◽  
Total Column ◽  
Daily Total

Abstract. One of the most significant events in the evolution of the ozone layer over southern mid-latitudes since the late 1970s was the large decrease observed in 1985. This event remains unexplained and a detailed investigation of the mechanisms responsible for the event has not previously been undertaken. In this study, the 1985 Southern Hemisphere mid-latitude total column ozone anomaly is analyzed in detail based on observed daily total column ozone fields, stratospheric dynamical fields, and calculated diagnostics of stratospheric mixing. The 1985 anomaly appears to result from a combination of (i) an anomaly in the meridional circulation resulting from the westerly phase of the equatorial quasi-biennial oscillation (QBO), (ii) weaker transport of ozone from its tropical mid-stratosphere source across the sub-tropical barrier to mid-latitudes related to the particular phasing of the QBO with respect to the annual cycle, and (iii) a solar cycle induced reduction in ozone. Similar QBO and solar cycle influences prevailed in 1997 and 2006 when again total column ozone was found to be suppressed over southern mid-latitudes. The results based on observations are compared and contrasted with analyses of ozone and dynamical fields from the ECHAM4.L39(DLR)/CHEM coupled chemistry-climate model (hereafter referred to as E39C). Equatorial winds in the E39C model are nudged towards observed winds between 10° S and 10° N and the ability of this model to produce an ozone anomaly in 1985, similar to that observed, confirms the role of the QBO in effecting the anomaly.

scholarly journals The 1985 southern hemisphere mid-latitude total column ozone anomaly

2007 ◽  
Vol 7 (3) ◽  
pp. 7137-7169
Author(s):  
G. E. Bodeker ◽  
H. Garny ◽  
D. Smale ◽  
M. Dameris ◽  
R. Deckert
Keyword(s):  
Southern Hemisphere ◽  
Atmospheric Chemistry ◽  
Climate Model ◽  
Transport Models ◽  
Quasi Biennial Oscillation ◽  
Total Column Ozone ◽  
Local Reduction ◽  
Column Ozone ◽  
Total Column

Abstract. One of the most significant events in the evolution of the ozone layer over southern mid-latitudes since the late 1970s was the large decrease observed in 1985. This event remains unexplained and most state-of-the-art atmospheric chemistry-transport models are unable to reproduce it. In this study, the 1985 southern hemisphere mid-latitude total column ozone anomaly is analyzed in detail based on observed daily total column ozone fields, stratospheric dynamical fields, and calculated diagnostics of stratospheric mixing. The 1985 anomaly appears to result from a combination of (i) an anomaly in the meridional circulation resulting from the westerly phase of the equatorial quasi-biennial oscillation (QBO), (ii) weaker transport of ozone from its tropical mid-stratosphere source across the sub-tropical barrier to mid-latitudes related to the particular phasing of the QBO with respect to the annual cycle, and (iii) a solar cycle induced local reduction in ozone. The results based on observations are compared and contrasted with analyses of ozone and dynamical fields from the ECHAM4.L39(DLR)/CHEM coupled chemistry-climate model (hereafter referred to as E39C). Equatorial winds in the E39C model are nudged towards observed winds between 10° S and 10° N and the ability of this model to produce an ozone anomaly in 1985, similar to that observed, confirms the role of the QBO in the anomaly.

scholarly journals A global historical ozone data set and prominent features of stratospheric variability prior to 1979

2013 ◽  
Vol 13 (18) ◽  
pp. 9623-9639 ◽  
Author(s):  
S. Brönnimann ◽  
J. Bhend ◽  
J. Franke ◽  
S. Flückiger ◽  
A. M. Fischer ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Greenhouse Gases ◽  
Southern Oscillation ◽  
Observation Error ◽  
Quasi Biennial Oscillation ◽  
Data Set ◽  
Total Column Ozone ◽  
Ozone Data ◽  
Column Ozone ◽  
Total Column

Abstract. We present a vertically resolved zonal mean monthly mean global ozone data set spanning the period 1901 to 2007, called HISTOZ.1.0. It is based on a new approach that combines information from an ensemble of chemistry climate model (CCM) simulations with historical total column ozone information. The CCM simulations incorporate important external drivers of stratospheric chemistry and dynamics (in particular solar and volcanic effects, greenhouse gases and ozone depleting substances, sea surface temperatures, and the quasi-biennial oscillation). The historical total column ozone observations include ground-based measurements from the 1920s onward and satellite observations from 1970 to 1976. An off-line data assimilation approach is used to combine model simulations, observations, and information on the observation error. The period starting in 1979 was used for validation with existing ozone data sets and therefore only ground-based measurements were assimilated. Results demonstrate considerable skill from the CCM simulations alone. Assimilating observations provides additional skill for total column ozone. With respect to the vertical ozone distribution, assimilating observations increases on average the correlation with a reference data set, but does not decrease the mean squared error. Analyses of HISTOZ.1.0 with respect to the effects of El Niño–Southern Oscillation (ENSO) and of the 11 yr solar cycle on stratospheric ozone from 1934 to 1979 qualitatively confirm previous studies that focussed on the post-1979 period. The ENSO signature exhibits a much clearer imprint of a change in strength of the Brewer–Dobson circulation compared to the post-1979 period. The imprint of the 11 yr solar cycle is slightly weaker in the earlier period. Furthermore, the total column ozone increase from the 1950s to around 1970 at northern mid-latitudes is briefly discussed. Indications for contributions of a tropospheric ozone increase, greenhouse gases, and changes in atmospheric circulation are found. Finally, the paper points at several possible future improvements of HISTOZ.1.0.

scholarly journals Interannual Variability and Trends of Extratropical Ozone. Part II: Southern Hemisphere

2008 ◽  
Vol 65 (10) ◽  
pp. 3030-3041 ◽  
Author(s):  
Xun Jiang ◽  
Steven Pawson ◽  
Charles D. Camp ◽  
J. Eric Nielsen ◽  
Run-Lie Shia ◽  
...  
Keyword(s):  
Interannual Variability ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Climate Model ◽  
Observation System ◽  
Stationary Waves ◽  
Quasi Biennial Oscillation ◽  
Total Column Ozone ◽  
The Third ◽  
Column Ozone

A principal component analysis (PCA) is applied to the Southern Hemisphere (SH) total column ozone following the method established for analyzing the data in the Northern Hemisphere (NH) in a companion paper. The interannual variability (IAV) of extratropical O3 in the SH is characterized by four main modes, which account for 75% of the total variance. The first two leading modes are approximately zonally symmetric and relate to the Southern Hemisphere annular mode and the quasi-biennial oscillation. The third and fourth modes exhibit wavenumber-1 structures. Contrary to the Northern Hemisphere, the third and fourth modes are not related to stationary waves. Similar results are obtained for the 30–100-hPa geopotential thickness. The decreasing O3 trend in the SH is captured in the first mode. The largest trend is at the South Pole, with value ∼−2 Dobson Units (DU) yr−1. Both the spatial pattern and trends in the column ozone are captured by the Goddard Earth Observation System chemistry–climate model (GEOS-CCM) in the SH.

scholarly journals On the relationship between total ozone and atmospheric dynamics and chemistry at mid-latitudes – Part 1: Statistical models and spatial fingerprints of atmospheric dynamics and chemistry

2012 ◽  
Vol 12 (5) ◽  
pp. 13161-13199 ◽  
Author(s):  
L. Frossard ◽  
H. E. Rieder ◽  
M. Ribatet ◽  
J. Staehelin ◽  
J. A. Maeder ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Statistical Models ◽  
Total Ozone ◽  
Volcanic Eruptions ◽  
Atmospheric Dynamics ◽  
Quasi Biennial Oscillation ◽  
Total Column Ozone ◽  
Value Analysis ◽  
Column Ozone ◽  
Total Column

Abstract. We use models for mean and extreme values of total column ozone on spatial scales to analyze "fingerprints" of atmospheric dynamics and chemistry on long-term ozone changes at northern and southern mid-latitudes. The r-largest order statistics method is used for pointwise analysis of extreme events in low and high total ozone (termed ELOs and EHOs, respectively). For the corresponding mean value analysis a pointwise autoregressive moving average model (ARMA) is used. The statistical models include important atmospheric covariates to describe the dynamical and chemical state of the atmosphere: the solar cycle, the Quasi-Biennial Oscillation (QBO), ozone depleting substances (ODS) in terms of equivalent effective stratospheric chlorine (EESC), the North Atlantic Oscillation (NAO), the Antarctic Oscillation (AAO), the El~Niño/Southern Oscillation (ENSO), and aerosol load after the volcanic eruptions of El Chichón and Mt. Pinatubo. The influence of the individual covariates on mean and extreme levels in total column ozone is derived on a grid cell basis. The results show that "fingerprints", i.e., significant influence, of dynamical and chemical features are captured in both the "bulk" and the tails of the ozone distribution, respectively described by means and EHOs/ELOs. While results for the solar cycle, QBO and EESC are in good agreement with findings of earlier studies, unprecedented spatial fingerprints are retrieved for the dynamical covariates.

scholarly journals Assessment of the Latitudinal Behavior of Total Column Ozone at Nine Discrete 1º-Wide Latitude Bands, from TOMS and OMI Data

2013 ◽  
Vol 7 (1) ◽  
pp. 92-109 ◽  
Author(s):  
Jose Luis Pinedo ◽  
Fernando Mireles-Garcia ◽  
Carlos Rios ◽  
Victor Manuel Garcia-Saldivar ◽  
J. Ignacio Davila-Rangel ◽  
...  
Keyword(s):  
Annual Variation ◽  
Polar Regions ◽  
Total Ozone Mapping Spectrometer ◽  
Ozone Monitoring Instrument ◽  
Quasi Biennial Oscillation ◽  
Total Column Ozone ◽  
Abrupt Changes ◽  
Column Ozone ◽  
Biennial Oscillation ◽  
Total Column

Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument OMI Version 8 data, from November 1978 to February 2013, have been used to retrieve the shape and amplitude of the daily mean of the total column ozone (TCO) and their associated dispersion over eleven selected 1°-wide latitude bands. Their inter-annual variation at 44.5° S, 23.5° S, 23.5° N, 44.5° N and 59.5° N shows a quasi-regular periodic behavior. However, Polar Regions exhibit abrupt changes, whereas at the Equator a complex perturbation of periodicity is highlighted, which could be associated to the effect of the quasi-biennial oscillation (QBO). The discrete 1°-wide latitude bands show a stabilization of TCO levels from the late nineties, but they do not display a generalized recovery. Indeed, at the Equator, between 1997 and 2013, a 1.4% per decade decrease in the total column ozone is exhibited, which may be significant given that during the 1987-1994 period the decrease was only of 0.5%. Additionally, the discrete bands reveal the appearance of a perturbation of the inter-annual ozone variations at 59.5° S, in contrast to regular behavior in the Northern Hemisphere and at other latitudes. The perturbation apparently begins in the 1980-1984 time series and is clear and systematic after 1998.

scholarly journals Analysis of Arctic Spring Ozone Anomaly in the Phases of QBO and 11-year Solar Cycle for 1979–2011

2021 ◽  
Author(s):  
Yousuke Yamashita ◽  
Hideharu Akiyoshi ◽  
Masaaki Takahashi
Keyword(s):  
Solar Cycle ◽  
Climate Model ◽  
Polar Vortex ◽  
Reanalysis Data ◽  
Early Spring ◽  
The Arctic ◽  
Negative Anomaly ◽  
Late Winter ◽  
Quasi Biennial Oscillation ◽  
Biennial Oscillation

Arctic ozone amount in winter to spring shows large year-to-year variation. This study investigates Arctic spring ozone in relation to the phase of quasi-biennial oscillation (QBO)/the 11-year solar cycle, using satellite observations, reanalysis data, and outputs of a chemistry climate model (CCM) during the period of 1979–2011. For this duration, we found that the composite mean of the Northern Hemisphere high-latitude total ozone in the QBO-westerly (QBO-W)/solar minimum (Smin) phase is slightly smaller than those averaged for the QBO-W/Smax and QBO-E/Smax years in March. An analysis of a passive ozone tracer in the CCM simulation indicates that this negative anomaly is primarily caused by transport. The negative anomaly is consistent with a weakening of the residual mean downward motion in the polar lower stratosphere. The contribution of chemical processes estimated using the column amount difference between ozone and the passive ozone tracer is between 10–20% of the total anomaly in March. The lower ozone levels in the Arctic spring during the QBO-W/Smin years are associated with a stronger Arctic polar vortex from late winter to early spring, which is linked to the reduced occurrence of sudden stratospheric warming in the winter during the QBO-W/Smin years.

scholarly journals Simple measures of ozone depletion in the polar stratosphere

2008 ◽  
Vol 8 (2) ◽  
pp. 251-264 ◽  
Author(s):  
R. Müller ◽  
J.-U. Grooß ◽  
C. Lemmen ◽  
D. Heinze ◽  
M. Dameris ◽  
...  
Keyword(s):  
Total Ozone ◽  
Climate Model ◽  
The Arctic ◽  
Total Column Ozone ◽  
Ozone Loss ◽  
Break Up ◽  
Column Ozone ◽  
The Impact ◽  
Polar Ozone ◽  
Daily Total

Abstract. We investigate the extent to which quantities that are based on total column ozone are applicable as measures of ozone loss in the polar vortices. Such quantities have been used frequently in ozone assessments by the World Meteorological Organization (WMO) and also to assess the performance of chemistry-climate models. The most commonly considered quantities are March and October mean column ozone poleward of geometric latitude 63° and the spring minimum of daily total ozone minima poleward of a given latitude. Particularly in the Arctic, the former measure is affected by vortex variability and vortex break-up in spring. The minimum of daily total ozone minima poleward of a particular latitude is debatable, insofar as it relies on one single measurement or model grid point. We find that, for Arctic conditions, this minimum value often occurs in air outside the polar vortex, both in the observations and in a chemistry-climate model. Neither of the two measures shows a good correlation with chemical ozone loss in the vortex deduced from observations. We recommend that the minimum of daily minima should no longer be used when comparing polar ozone loss in observations and models. As an alternative to the March and October mean column polar ozone we suggest considering the minimum of daily average total ozone poleward of 63° equivalent latitude in spring (except for winters with an early vortex break-up). Such a definition both obviates relying on one single data point and reduces the impact of year-to-year variability in the Arctic vortex break-up on ozone loss measures. Further, this measure shows a reasonable correlation (r=–0.75) with observed chemical ozone loss. Nonetheless, simple measures of polar ozone loss must be used with caution; if possible, it is preferable to use more sophisticated measures that include additional information to disentangle the impact of transport and chemistry on ozone.

scholarly journals Ozone sensitivity to varying greenhouse gases and ozone-depleting substances in CCMI simulations

2017 ◽  
Author(s):  
Olaf Morgenstern ◽  
Hideharu Akiyoshi ◽  
Yousuke Yamashita ◽  
Douglas E. Kinnison ◽  
Rolando R. Garcia ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Climate Model ◽  
Phase 1 ◽  
Coupled Model ◽  
Total Column Ozone ◽  
Ozone Sensitivity ◽  
Intercomparison Project ◽  
Ozone Depleting Substances ◽  
Column Ozone ◽  
Total Column

Abstract. Ozone fields simulated for the Chemistry-Climate Model Initiative (CCMI) will be used as forcing data in the 6th Coupled Model Intercomparison Project (CMIP6). Here we assess, using reference and sensitivity simulations produced for phase 1 of CCMI, the suitability of CCMI-1 model results for this process, investigating the degree of consistency amongst models regarding their responses to variations in individual forcings. We consider the influences of methane, nitrous oxide, a combination of chlorinated or brominated ozone-depleting substances (ODSs), and a combination of carbon dioxide and other greenhouse gases (GHGs). We find varying degrees of consistency in the models' responses in ozone to these individual forcings, including some considerable disagreement. In particular, the response of total-column ozone to these forcings is less consistent across the multi-model ensemble than profile comparisons. The likely cause of this is lower-stratospheric transport and dynamical responses exhibiting substantial inter-model differences. The findings imply that the ozone fields derived from CCMI-1 are subject to considerable uncertainties regarding the impacts of these anthropogenic forcings.

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